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8,237 | Don Quixote | Don Quixote is a Spanish epic novel by Miguel de Cervantes. It was originally published in two parts, in 1605 and 1615. Considered a founding work of Western literature, it is often labelled as the first modern novel and one of the greatest works ever written. Don Quixote is also one of the most-translated books in the world and one of the best-selling novels of all time.
The plot revolves around the adventures of a member of the lowest nobility, an hidalgo from La Mancha named Alonso Quijano, who reads so many chivalric romances that he loses his mind and decides to become a knight-errant (caballero andante) to revive chivalry and serve his nation, under the name Don Quixote de la Mancha. He recruits as his squire a simple farm labourer, Sancho Panza, who brings a unique, earthy wit to Don Quixote's lofty rhetoric. In the first part of the book, Don Quixote does not see the world for what it is and prefers to imagine that he is living out a knightly story meant for the annals of all time. However, as Salvador de Madariaga pointed out in his Guía del lector del Quijote (1972 [1926]), referring to "the Sanchification of Don Quixote and the Quixotization of Sancho", as "Sancho's spirit ascends from reality to illusion, Don Quixote's declines from illusion to reality".
The book had a major influence on the literary community, as evidenced by direct references in Alexandre Dumas' The Three Musketeers (1844), and Edmond Rostand's Cyrano de Bergerac (1897) as well as the word quixotic. Mark Twain referred to the book as having "swept the world's admiration for the mediaeval chivalry-silliness out of existence".
For Cervantes and the readers of his day, Don Quixote was a one-volume book published in 1605, divided internally into four parts, not the first part of a two-part set. The mention in the 1605 book of further adventures yet to be told was totally conventional, did not indicate any authorial plans for a continuation, and was not taken seriously by the book's first readers.
Cervantes, in a metafictional narrative, writes that the first chapters were taken from "the archives of La Mancha", and the rest were translated from an Arabic text by the Moorish historian Cide Hamete Benengeli.
Alonso Quixano is an hidalgo nearing 50 years of age who lives in an unspecified region of La Mancha with his niece and housekeeper. While he lives a frugal life, as an avid reader of chivalric romances, he is full of fantasies about chivalry. Eventually, he goes mad and decides to become a knight errant. To that end, he dons an old suit of armor, renames himself "Don Quixote", names his old workhorse "Rocinante", and designates Aldonza Lorenzo (a slaughterhouse worker with a famed hand for salting pork) his lady love, renaming her Dulcinea del Toboso.
As he travels in search of adventure, he arrives at an inn that he believes to be a castle, calls the prostitutes he meets there "ladies", and demands that the innkeeper, whom he takes to be the lord of the castle, dub him a knight. The innkeeper agrees. Quixote starts the night holding vigil at the inn's horse trough, which Quixote imagines to be a chapel. He then becomes involved in a fight with muleteers who try to remove his armor from the horse trough so that they can water their mules. In a pretended ceremony, the innkeeper dubs him a knight to be rid of him and sends him on his way.
Quixote encounters a servant named Andres who is tied to a tree and who is being beaten by his master over disputed wages. Quixote orders the master to stop beating Andres and untie him and makes the master swear to treat Andres fairly. However, the beating is resumed, and redoubled, as soon as Quixote leaves.
Quixote then encounters traders from Toledo. He challenges them to agree that Dulcinea del Toboso is the most beautiful woman in the world. One of them demands to see her picture so that he can decide for himself. Enraged, Quixote charges at them but his horse stumbles, causing him to fall. One of the traders beats up Quixote, who is left at the side of the road until a neighboring peasant brings him back home.
While Quixote lies unconscious in his bed, his niece, the housekeeper, the parish curate, and the local barber burn most of his chivalric and other books. They seal up the room which contained the library, later telling Quixote that it was done by a wizard.
Don Quixote asks his neighbour, the poor farm labourer Sancho Panza, to be his squire, promising him a petty governorship. Sancho agrees and they sneak away at dawn. Their adventures together begin with Quixote's attack on some windmills which he believes to be ferocious giants. They next encounter two Benedictine friars and, nearby, an unrelated lady in a carriage. Quixote takes the friars to be enchanters who are holding the lady captive, knocks one of them from his horse, and is challenged by an armed Basque travelling with the company. The combat ends with the lady leaving her carriage and commanding those travelling with her to "surrender" to Quixote.
After a friendly encounter with some goatherds and a less friendly one with some Yanguesan porters driving Galician ponies, Quixote and Sancho return to the "castle" (inn), where a mix-up involving a servant girl's romantic rendezvous with another guest results in a brawl. Quixote explains to Sancho that the castle is enchanted. They decide to leave, but Quixote, following the example of the fictional knights, leaves without paying. Sancho ends up wrapped in a blanket and tossed in the air by several mischievous guests at the inn before he manages to follow.
After further adventures involving a dead body, a legendary helmet (in Quixote's mind), and a group of galley slaves, they wander into the Sierra Morena. There they encounter the dejected and mostly mad Cardenio, who relates his story. Quixote decides to imitate Cardenio and live like a hermit. He sends Sancho to deliver a letter to Dulcinea, but instead Sancho finds the barber and priest from his village. They make a plan to trick Quixote into coming home, recruiting Dorotea, a woman they discover in the forest, to pose as the Princess Micomicona, a damsel in distress.
The plan works and Quixote and the group return to the inn, though Quixote is now convinced, thanks to a lie told by Sancho when asked about the letter, that Dulcinea wants to see him. At the inn, several other plots intersect and are resolved. Meanwhile, a sleepwalking Quixote does battle with some wineskins which he takes to be the giant who stole the princess Micomicona's kingdom. An officer of the Santa Hermandad arrives with a warrant for Quixote's arrest for freeing the galley slaves, but the priest begs for the officer to have mercy on account of Quixote's insanity. The officer agrees and Quixote is locked in a cage which he is made to think is an enchantment. He has a learned conversation with a Toledo canon he encounters by chance on the road, in which the canon expresses his scorn for untruthful chivalric books, but Don Quixote defends them. The group stops to eat and lets Quixote out of the cage; he gets into a fight with a goatherd and with a group of pilgrims, who beat him into submission, before he is finally brought home.
The narrator ends the story by saying that he has found manuscripts of Quixote's further adventures.
Although the two parts are now published as a single work, Don Quixote, Part Two was a sequel published ten years after the original novel. In an early example of metafiction, Part Two assumes that several of its characters have read the first part of the novel and are thus familiar with the history and peculiarities of the two protagonists.
Don Quixote and Sancho are on their way to El Toboso to meet Dulcinea, with Sancho aware that his story about Dulcinea was a complete fabrication. They reach the city at daybreak and decide to enter at nightfall. However, a bad omen frightens Quixote into retreat and they quickly leave. Sancho is instead sent out alone by Quixote to meet Dulcinea and act as a go-between. Sancho's luck brings three peasant girls along the road and he quickly tells Quixote that they are Dulcinea and her ladies-in-waiting and as beautiful as ever. Since Quixote only sees the peasant girls, Sancho goes on to pretend that an enchantment of some sort is at work.
A duke and duchess encounter the duo. These nobles have read Part One of the story and are themselves very fond of books of chivalry. They decide to play along for their own amusement, beginning a string of imagined adventures and practical jokes. As part of one prank, Quixote and Sancho are led to believe that the only way to release Dulcinea from her spell is for Sancho to give himself three thousand three hundred lashes. Sancho naturally resists this course of action, leading to friction with his master. Under the duke's patronage, Sancho eventually gets his promised governorship, though it is false, and he proves to be a wise and practical ruler before all ends in humiliation. Near the end, Don Quixote reluctantly sways towards sanity.
Quixote battles the Knight of the White Moon (a young man from Quixote's hometown who had earlier posed as the Knight of Mirrors) on the beach in Barcelona. Defeated, Quixote submits to prearranged chivalric terms: the vanquished must obey the will of the conqueror. He is ordered to lay down his arms and cease his acts of chivalry for a period of one year, by which time his friends and relatives hope he will be cured.
On the way back home, Quixote and Sancho "resolve" the disenchantment of Dulcinea. Upon returning to his village, Quixote announces his plan to retire to the countryside as a shepherd, but his housekeeper urges him to stay at home. Soon after, he retires to his bed with a deathly illness, and later awakes from a dream, having fully become Alonso Quixano once more. Sancho tries to restore his faith and his interest in Dulcinea, but Quixano only renounces his previous ambition and apologizes for the harm he has caused. He dictates his will, which includes a provision that his niece will be disinherited if she marries a man who reads books of chivalry.
After Quixano dies, the author emphasizes that there are no more adventures to relate and that any further books about Don Quixote would be spurious.
Don Quixote, Part One contains a number of stories which do not directly involve the two main characters, but which are narrated by some of the picaresque figures encountered by the Don and Sancho during their travels. The longest and best known of these is "El Curioso Impertinente" (The Ill-Advised Curiosity), found in Part One, Book Four. This story, read to a group of travelers at an inn, tells of a Florentine nobleman, Anselmo, who becomes obsessed with testing his wife's fidelity and talks his close friend Lothario into attempting to seduce her, with disastrous results for all.
In Part Two, the author acknowledges the criticism of his digressions in Part One and promises to concentrate the narrative on the central characters (although at one point he laments that his narrative muse has been constrained in this manner). Nevertheless, "Part Two" contains several back narratives related by peripheral characters.
Several abridged editions have been published which delete some or all of the extra tales in order to concentrate on the central narrative.
The story within a story relates that, for no particular reason, Anselmo decides to test the fidelity of his wife, Camilla, and asks his friend, Lothario, to seduce her. Thinking that to be madness, Lothario reluctantly agrees, and soon reports to Anselmo that Camilla is a faithful wife. Anselmo learns that Lothario has lied and attempted no seduction. He makes Lothario promise to try in earnest and leaves town to make this easier. Lothario tries and Camilla writes letters to her husband telling him of the attempts by Lothario and asking him to return. Anselmo makes no reply and does not return. Lothario then falls in love with Camilla, who eventually reciprocates; an affair between them ensues, but is not disclosed to Anselmo, and their affair continues after Anselmo returns.
One day, Lothario sees a man leaving Camilla's house and jealously presumes she has taken another lover. He tells Anselmo that, at last, he has been successful and arranges a time and place for Anselmo to see the seduction. Before this rendezvous, however, Lothario learns that the man was the lover of Camilla's maid. He and Camilla then contrive to deceive Anselmo further: When Anselmo watches them, she refuses Lothario, protests her love for her husband, and stabs herself lightly in the breast. Anselmo is reassured of her fidelity. The affair restarts with Anselmo none the wiser.
Later, the maid's lover is discovered by Anselmo. Fearing that Anselmo will kill her, the maid says she will tell Anselmo a secret the next day. Anselmo tells Camilla that this is to happen, and Camilla expects that her affair is to be revealed. Lothario and Camilla flee that night. The maid flees the next day. Anselmo searches for them in vain before learning from a stranger of his wife's affair. He starts to write the story, but dies of grief before he can finish. Lothario is killed in battle soon afterward and Camilla dies of grief.
The novel's farcical elements make use of punning and similar verbal playfulness. Character-naming in Don Quixote makes ample figural use of contradiction, inversion, and irony, such as the names Rocinante (a reversal) and Dulcinea (an allusion to illusion), and the word quixote itself, possibly a pun on quijada (jaw) but certainly cuixot (Catalan: thighs), a reference to a horse's rump.
As a military term, the word quijote refers to cuisses, part of a full suit of plate armour protecting the thighs. The Spanish suffix -ote denotes the augmentative—for example, grande means large, but grandote means extra large, with grotesque connotations. Following this example, Quixote would suggest 'The Great Quijano', an oxymoronic play on words that makes much sense in light of the character's delusions of grandeur.
Cervantes wrote his work in Early Modern Spanish, heavily borrowing from Old Spanish, the medieval form of the language. The language of Don Quixote, although still containing archaisms, is far more understandable to modern Spanish readers than is, for instance, the completely medieval Spanish of the Poema de mio Cid, a kind of Spanish that is as different from Cervantes' language as Middle English is from Modern English. The Old Castilian language was also used to show the higher class that came with being a knight errant.
In Don Quixote, there are basically two different types of Castilian: Old Castilian is spoken only by Don Quixote, while the rest of the roles speak a contemporary (late 16th century) version of Spanish. The Old Castilian of Don Quixote is a humoristic resource—he copies the language spoken in the chivalric books that made him mad; and many times, when he talks nobody is able to understand him because his language is too old. This humorous effect is more difficult to see nowadays because the reader must be able to distinguish the two old versions of the language, but when the book was published it was much celebrated. (English translations can get some sense of the effect by having Don Quixote use King James Bible or Shakespearean English, or even Middle English.)
In Old Castilian, the letter x represented the sound written sh in modern English, so the name was originally pronounced [kiˈʃote]. However, as Old Castilian evolved towards modern Spanish, a sound change caused it to be pronounced with a voiceless velar fricative [x] sound (like the Scots or German ch), and today the Spanish pronunciation of "Quixote" is [kiˈxote]. The original pronunciation is reflected in languages such as Asturian, Leonese, Galician, Catalan, Italian, Portuguese, Turkish and French, where it is pronounced with a "sh" or "ch" sound; the French opera Don Quichotte is one of the best-known modern examples of this pronunciation.
Today, English speakers generally attempt something close to the modern Spanish pronunciation of Quixote (Quijote), as /kiːˈhoʊti/, although the traditional English spelling-based pronunciation with the value of the letter x in modern English is still sometimes used, resulting in /ˈkwɪksət/ or /ˈkwɪksoʊt/. In Australian English, the preferred pronunciation amongst members of the educated classes was /ˈkwɪksət/ until well into the 1970s, as part of a tendency for the upper class to "anglicise its borrowing ruthlessly". The traditional English rendering is preserved in the pronunciation of the adjectival form quixotic, i.e., /kwɪkˈsɒtɪk/, defined by Merriam-Webster as the foolishly impractical pursuit of ideals, typically marked by rash and lofty romanticism.
Harold Bloom says Don Quixote is the first modern novel, and that the protagonist is at war with Freud's reality principle, which accepts the necessity of dying. Bloom says that the novel has an endless range of meanings, but that a recurring theme is the human need to withstand suffering.
Edith Grossman, who wrote and published a highly acclaimed English translation of the novel in 2003, says that the book is mostly meant to move people into emotion using a systematic change of course, on the verge of both tragedy and comedy at the same time. Grossman has stated:
The question is that Quixote has multiple interpretations [...] and how do I deal with that in my translation. I'm going to answer your question by avoiding it [...] so when I first started reading the Quixote I thought it was the most tragic book in the world, and I would read it and weep [...] As I grew older [...] my skin grew thicker [...] and so when I was working on the translation I was actually sitting at my computer and laughing out loud. This is done [...] as Cervantes did it [...] by never letting the reader rest. You are never certain that you truly got it. Because as soon as you think you understand something, Cervantes introduces something that contradicts your premise.
The novel's structure is episodic in form. The full title is indicative of the tale's object, as ingenioso (Spanish) means "quick with inventiveness", marking the transition of modern literature from dramatic to thematic unity. The novel takes place over a long period of time, including many adventures united by common themes of the nature of reality, reading, and dialogue in general.
Although burlesque on the surface, the novel, especially in its second half, has served as an important thematic source not only in literature but also in much of art and music, inspiring works by Pablo Picasso and Richard Strauss. The contrasts between the tall, thin, fancy-struck and idealistic Quixote and the fat, squat, world-weary Panza is a motif echoed ever since the book's publication, and Don Quixote's imaginings are the butt of outrageous and cruel practical jokes in the novel.
Even faithful and simple Sancho is forced to deceive him at certain points. The novel is considered a satire of orthodoxy, veracity and even nationalism. In exploring the individualism of his characters, Cervantes helped lead literary practice beyond the narrow convention of the chivalric romance. He spoofs the chivalric romance through a straightforward retelling of a series of acts that redound to the knightly virtues of the hero. The character of Don Quixote became so well known in its time that the word quixotic was quickly adopted by many languages. Characters such as Sancho Panza and Don Quixote's steed, Rocinante, are emblems of Western literary culture. The phrase "tilting at windmills" to describe an act of attacking imaginary enemies (or an act of extreme idealism), derives from an iconic scene in the book.
It stands in a unique position between medieval romance and the modern novel. The former consists of disconnected stories featuring the same characters and settings with little exploration of the inner life of even the main character. The latter are usually focused on the psychological evolution of their characters. In Part I, Quixote imposes himself on his environment. By Part II, people know about him through "having read his adventures", and so, he needs to do less to maintain his image. By his deathbed, he has regained his sanity, and is once more "Alonso Quixano the Good".
Sources for Don Quixote include the Castilian novel Amadis de Gaula, which had enjoyed great popularity throughout the 16th century. Another prominent source, which Cervantes evidently admires more, is Tirant lo Blanch, which the priest describes in Chapter VI of Quixote as "the best book in the world." (However, the sense in which it was "best" is much debated among scholars. Since the 19th century, the passage has been called "the most difficult passage of Don Quixote".) The scene of the book burning gives an excellent list of Cervantes's likes and dislikes about literature.
Cervantes makes a number of references to the Italian poem Orlando furioso. In chapter 10 of the first part of the novel, Don Quixote says he must take the magical helmet of Mambrino, an episode from Canto I of Orlando, and itself a reference to Matteo Maria Boiardo's Orlando innamorato. The interpolated story in chapter 33 of Part four of the First Part is a retelling of a tale from Canto 43 of Orlando, regarding a man who tests the fidelity of his wife.
Another important source appears to have been Apuleius's The Golden Ass, one of the earliest known novels, a picaresque from late classical antiquity. The wineskins episode near the end of the interpolated tale "The Curious Impertinent" in chapter 35 of the first part of Don Quixote is a clear reference to Apuleius, and recent scholarship suggests that the moral philosophy and the basic trajectory of Apuleius's novel are fundamental to Cervantes' program. Similarly, many of both Sancho's adventures in Part II and proverbs throughout are taken from popular Spanish and Italian folklore.
Cervantes' experiences as a galley slave in Algiers also influenced Quixote.
Medical theories may have also influenced Cervantes' literary process. Cervantes had familial ties to the distinguished medical community. His father, Rodrigo de Cervantes, and his great-grandfather, Juan Díaz de Torreblanca, were surgeons. Additionally, his sister, Andrea de Cervantes, was a nurse. He also befriended many individuals involved in the medical field, in that he knew medical author Francisco Díaz, an expert in urology, and royal doctor Antonio Ponce de Santa Cruz who served as a personal doctor to both Philip III and Philip IV of Spain.
Apart from the personal relations Cervantes maintained within the medical field, Cervantes' personal life was defined by an interest in medicine. He frequently visited patients from the Hospital de Inocentes in Sevilla. Furthermore, Cervantes explored medicine in his personal library. His library contained more than 200 volumes and included books like Examen de Ingenios, by Juan Huarte and Practica y teórica de cirugía, by Dionisio Daza Chacón that defined medical literature and medical theories of his time.
Researchers Isabel Sanchez Duque and Francisco Javier Escudero have found that Cervantes was a friend of the family Villaseñor, which was involved in a combat with Francisco de Acuña. Both sides combated disguised as medieval knights in the road from El Toboso to Miguel Esteban in 1581. They also found a person called Rodrigo Quijada, who bought the title of nobility of "hidalgo", and created diverse conflicts with the help of a squire.
It is not certain when Cervantes began writing Part Two of Don Quixote, but he had probably not proceeded much further than Chapter LIX by late July 1614. In about September, however, a spurious Part Two, entitled Second Volume of the Ingenious Gentleman Don Quixote of La Mancha: by the Licenciado (doctorate) Alonso Fernández de Avellaneda, of Tordesillas, was published in Tarragona by an unidentified Aragonese who was an admirer of Lope de Vega, rival of Cervantes. It was translated into English by William Augustus Yardley, Esquire in two volumes in 1784.
Some modern scholars suggest that Don Quixote's fictional encounter with Avellaneda's book in Chapter 59 of Part II should not be taken as the date that Cervantes encountered it, which may have been much earlier.
Avellaneda's identity has been the subject of many theories, but there is no consensus as to who he was. In its prologue, the author gratuitously insulted Cervantes, who took offense and responded; the last half of Chapter LIX and most of the following chapters of Cervantes's Segunda Parte lend some insight into the effects upon him; Cervantes manages to work in some subtle digs at Avellaneda's own work, and in his preface to Part II, comes very near to criticizing Avellaneda directly.
In his introduction to The Portable Cervantes, Samuel Putnam, a noted translator of Cervantes' novel, calls Avellaneda's version "one of the most disgraceful performances in history".
The second part of Cervantes' Don Quixote, finished as a direct result of the Avellaneda book, has come to be regarded by some literary critics as superior to the first part, because of its greater depth of characterization, its discussions, mostly between Quixote and Sancho, on diverse subjects, and its philosophical insights. In Cervantes's Segunda Parte, Don Quixote visits a printing-house in Barcelona and finds Avellaneda's Second Part being printed there, in an early example of metafiction. Don Quixote and Sancho Panza also meet one of the characters from Avellaneda's book, Don Alvaro Tarfe, and make him swear that the “other” Quixote and Sancho are impostors.
Cervantes' story takes place on the plains of La Mancha, specifically the comarca of Campo de Montiel.
En un lugar de La Mancha, de cuyo nombre no quiero acordarme, no ha mucho tiempo que vivía un hidalgo de los de lanza en astillero, adarga antigua, rocín flaco y galgo corredor.(Somewhere in La Mancha, in a place whose name I do not care to remember, a gentleman lived not long ago, one of those who has a lance and ancient shield on a shelf and keeps a skinny nag and a greyhound for racing.)
The location of the village to which Cervantes alludes in the opening sentence of Don Quixote has been the subject of debate since its publication over four centuries ago. Indeed, Cervantes deliberately omits the name of the village, giving an explanation in the final chapter:
Such was the end of the Ingenious Gentleman of La Mancha, whose village Cide Hamete would not indicate precisely, in order to leave all the towns and villages of La Mancha to contend among themselves for the right to adopt him and claim him as a son, as the seven cities of Greece contended for Homer.
In 2004, a multidisciplinary team of academics from Complutense University, led by Francisco Parra Luna, Manuel Fernández Nieto, and Santiago Petschen Verdaguer, deduced that the village was that of Villanueva de los Infantes. Their findings were published in a paper titled "'El Quijote' como un sistema de distancias/tiempos: hacia la localización del lugar de la Mancha", which was later published as a book: El enigma resuelto del Quijote. The result was replicated in two subsequent investigations: "La determinación del lugar de la Mancha como problema estadístico" and "The Kinematics of the Quixote and the Identity of the 'Place in La Mancha'".
Translators of Don Quixote, such as John Ormsby, have commented that the region of La Mancha is one of the most desertlike, unremarkable regions of Spain, the least romantic and fanciful place that one would imagine as the home of a courageous knight.
On the other hand, as Borges points out:
I suspect that in Don Quixote, it does not rain a single time. The landscapes described by Cervantes have nothing in common with the landscapes of Castile: they are conventional landscapes, full of meadows, streams, and copses that belong in an Italian novel.
The story also takes place in El Toboso where Don Quixote goes to seek Dulcinea's blessings.
Don Quixote is said to reflect the Spanish society in which Cervantes lived and wrote. Spain's status as a world power was declining, and the Spanish national treasury was bankrupt due to expensive foreign wars. Spanish cultural dominance was also waning as the Protestant Reformation had put the Spanish Roman Catholic Church on the defensive, which had led to the establishment of the Spanish Inquisition. Meanwhile, the hidalgo class was losing relevance because of changes in Spanish society which made the high ideals of chivalry obsolete.
Don Quixote continues to be the origin of replication for authors. In 2002 the Norwegian Nobel Institute conducted a study among writers from 55 countries, the majority voted Don Quixote "the greatest work of fiction ever written".
The opening sentence of the book created a classic Spanish cliché with the phrase de cuyo nombre no quiero acordarme ("whose name I do not wish to recall"): En un lugar de la Mancha, de cuyo nombre no quiero acordarme, no hace mucho tiempo que vivía un hidalgo de los de lanza en astillero, adarga antigua, rocín flaco y galgo corredor. ("In a village of La Mancha, whose name I do not wish to recall, there lived, not very long ago, one of those gentlemen with a lance in the lance-rack, an ancient shield, a skinny old horse, and a fast greyhound.")
Don Quixote alongside its many translations, has also provided a number of idioms and expressions to the English language. Examples with their own articles include the phrase "the pot calling the kettle black" and the adjective "quixotic."
Tilting at windmills is an English idiom that means "attacking imaginary enemies". The expression is derived from Don Quixote, and the word "tilt" in this context refers to jousting. This phrase is sometimes also expressed as "charging at windmills" or "fighting the windmills".
The phrase is sometimes used to describe either confrontations where adversaries are incorrectly perceived, or courses of action that are based on misinterpreted or misapplied heroic, romantic, or idealistic justifications. It may also connote an inopportune, unfounded, and vain effort against adversaries real or imagined.
In July 1604, Cervantes sold the rights of El ingenioso hidalgo don Quixote de la Mancha (known as Don Quixote, Part I) to the publisher-bookseller Francisco de Robles for an unknown sum. License to publish was granted in September, the printing was finished in December, and the book came out on 16 January 1605.
The novel was an immediate success. Most of the 400 copies of the first edition were sent to the New World, with the publisher hoping to get a better price in the Americas. Although most of them disappeared in a shipwreck near La Havana, approximately 70 copies reached Lima, from where they were sent to Cuzco, in the heart of the defunct Inca Empire.
No sooner was it in the hands of the public than preparations were made to issue derivative (pirated) editions. In 1614 a fake second part was published by a mysterious author under the pen name Avellaneda. This author was never satisfactorily identified. This rushed Cervantes into writing and publishing a genuine second part in 1615, which was a year before his own death. Don Quixote had been growing in favour, and its author's name was now known beyond the Pyrenees. By August 1605, there were two Madrid editions, two published in Lisbon, and one in Valencia. Publisher Francisco de Robles secured additional copyrights for Aragon and Portugal for a second edition.
Sale of these publishing rights deprived Cervantes of further financial profit on Part One. In 1607, an edition was printed in Brussels. Robles, the Madrid publisher, found it necessary to meet demand with a third edition, a seventh publication in all, in 1608. Popularity of the book in Italy was such that a Milan bookseller issued an Italian edition in 1610. Yet another Brussels edition was called for in 1611. Since then, numerous editions have been released and in total, the novel is believed to have sold more than 500 million copies worldwide. The work has been produced in numerous editions and languages, the Cervantes Collection, at the State Library of New South Wales includes over 1,100 editions. These were collected, by Ben Haneman, over a period of thirty years.
In 1613, Cervantes published the Novelas ejemplares, dedicated to the Maecenas of the day, the Conde de Lemos. Eight and a half years after Part One had appeared came the first hint of a forthcoming Segunda Parte (Part Two). "You shall see shortly", Cervantes says, "the further exploits of Don Quixote and humours of Sancho Panza." Don Quixote, Part Two, published by the same press as its predecessor, appeared late in 1615, and quickly reprinted in Brussels and Valencia (1616) and Lisbon (1617). Parts One and Two were published as one edition in Barcelona in 1617. Historically, Cervantes' work has been said to have "smiled Spain's chivalry away", suggesting that Don Quixote as a chivalric satire contributed to the demise of Spanish Chivalry.
There are many translations of the book, and it has been adapted many times in shortened versions. Many derivative editions were also written at the time, as was the custom of envious or unscrupulous writers. Seven years after the Parte Primera appeared, Don Quixote had been translated into French, German, Italian, and English, with the first French translation of 'Part II' appearing in 1618, and the first English translation in 1620. One abridged adaptation, authored by Agustín Sánchez, runs slightly over 150 pages, cutting away about 750 pages.
Thomas Shelton's English translation of the First Part appeared in 1612 while Cervantes was still alive, although there is no evidence that Shelton had met the author. Although Shelton's version is cherished by some, according to John Ormsby and Samuel Putnam, it was far from satisfactory as a carrying over of Cervantes' text. Shelton's translation of the novel's Second Part appeared in 1620.
Near the end of the 17th century, John Phillips, a nephew of poet John Milton, published what Putnam considered the worst English translation. The translation, as literary critics claim, was not based on Cervantes' text but mostly on a French work by Filleau de Saint-Martin and on notes which Thomas Shelton had written.
Around 1700, a version by Pierre Antoine Motteux appeared. Motteux's translation enjoyed lasting popularity; it was reprinted as the Modern Library Series edition of the novel until recent times. Nonetheless, future translators would find much to fault in Motteux's version: Samuel Putnam criticized "the prevailing slapstick quality of this work, especially where Sancho Panza is involved, the obtrusion of the obscene where it is found in the original, and the slurring of difficulties through omissions or expanding upon the text". John Ormsby considered Motteux's version "worse than worthless", and denounced its "infusion of Cockney flippancy and facetiousness" into the original.
The proverb "The proof of the pudding is in the eating" is widely attributed to Cervantes. The Spanish word for pudding (budín), however, does not appear in the original text but premieres in the Motteux translation. In Smollett's translation of 1755 he notes that the original text reads literally "you will see when the eggs are fried", meaning "time will tell".
A translation by Captain John Stevens, which revised Thomas Shelton's version, also appeared in 1700, but its publication was overshadowed by the simultaneous release of Motteux's translation.
In 1742, the Charles Jervas translation appeared, posthumously. Through a printer's error, it came to be known, and is still known, as "the Jarvis translation". It was the most scholarly and accurate English translation of the novel up to that time, but future translator John Ormsby points out in his own introduction to the novel that the Jarvis translation has been criticized as being too stiff. Nevertheless, it became the most frequently reprinted translation of the novel until about 1885. Another 18th-century translation into English was that of Tobias Smollett, himself a novelist, first published in 1755. Like the Jarvis translation, it continues to be reprinted today.
A translation by Alexander James Duffield appeared in 1881 and another by Henry Edward Watts in 1888. Most modern translators take as their model the 1885 translation by John Ormsby.
An expurgated children's version, under the title The Story of Don Quixote, was published in 1922 (available on Project Gutenberg). It leaves out the risqué sections as well as chapters that young readers might consider dull, and embellishes a great deal on Cervantes' original text. The title page actually gives credit to the two editors as if they were the authors, and omits any mention of Cervantes.
The most widely read English-language translations of the mid-20th century are by Samuel Putnam (1949), J. M. Cohen (1950; Penguin Classics), and Walter Starkie (1957). The last English translation of the novel in the 20th century was by Burton Raffel, published in 1996. The 21st century has already seen five new translations of the novel into English. The first is by John D. Rutherford and the second by Edith Grossman. Reviewing the novel in The New York Times, Carlos Fuentes called Grossman's translation a "major literary achievement" and another called it the "most transparent and least impeded among more than a dozen English translations going back to the 17th century."
In 2005, the year of the novel's 400th anniversary, Tom Lathrop published a new English translation of the novel, based on a lifetime of specialized study of the novel and its history. The fourth translation of the 21st century was released in 2006 by former university librarian James H. Montgomery, 26 years after he had begun it, in an attempt to "recreate the sense of the original as closely as possible, though not at the expense of Cervantes' literary style."
In 2011, another translation by Gerald J. Davis appeared. It is the latest and the fifth translation of the 21st century, though it is self published via Lulu.com.
Reviewing the English translations as a whole, Daniel Eisenberg stated that there is no one translation ideal for every purpose, but expressed a preference for those of Putnam and the revision of Ormsby's translation by Douglas and Jones. | [
{
"paragraph_id": 0,
"text": "Don Quixote is a Spanish epic novel by Miguel de Cervantes. It was originally published in two parts, in 1605 and 1615. Considered a founding work of Western literature, it is often labelled as the first modern novel and one of the greatest works ever written. Don Quixote is also one of the most-translated books in the world and one of the best-selling novels of all time.",
"title": ""
},
{
"paragraph_id": 1,
"text": "The plot revolves around the adventures of a member of the lowest nobility, an hidalgo from La Mancha named Alonso Quijano, who reads so many chivalric romances that he loses his mind and decides to become a knight-errant (caballero andante) to revive chivalry and serve his nation, under the name Don Quixote de la Mancha. He recruits as his squire a simple farm labourer, Sancho Panza, who brings a unique, earthy wit to Don Quixote's lofty rhetoric. In the first part of the book, Don Quixote does not see the world for what it is and prefers to imagine that he is living out a knightly story meant for the annals of all time. However, as Salvador de Madariaga pointed out in his Guía del lector del Quijote (1972 [1926]), referring to \"the Sanchification of Don Quixote and the Quixotization of Sancho\", as \"Sancho's spirit ascends from reality to illusion, Don Quixote's declines from illusion to reality\".",
"title": ""
},
{
"paragraph_id": 2,
"text": "The book had a major influence on the literary community, as evidenced by direct references in Alexandre Dumas' The Three Musketeers (1844), and Edmond Rostand's Cyrano de Bergerac (1897) as well as the word quixotic. Mark Twain referred to the book as having \"swept the world's admiration for the mediaeval chivalry-silliness out of existence\".",
"title": ""
},
{
"paragraph_id": 3,
"text": "For Cervantes and the readers of his day, Don Quixote was a one-volume book published in 1605, divided internally into four parts, not the first part of a two-part set. The mention in the 1605 book of further adventures yet to be told was totally conventional, did not indicate any authorial plans for a continuation, and was not taken seriously by the book's first readers.",
"title": "Summary"
},
{
"paragraph_id": 4,
"text": "Cervantes, in a metafictional narrative, writes that the first chapters were taken from \"the archives of La Mancha\", and the rest were translated from an Arabic text by the Moorish historian Cide Hamete Benengeli.",
"title": "Summary"
},
{
"paragraph_id": 5,
"text": "Alonso Quixano is an hidalgo nearing 50 years of age who lives in an unspecified region of La Mancha with his niece and housekeeper. While he lives a frugal life, as an avid reader of chivalric romances, he is full of fantasies about chivalry. Eventually, he goes mad and decides to become a knight errant. To that end, he dons an old suit of armor, renames himself \"Don Quixote\", names his old workhorse \"Rocinante\", and designates Aldonza Lorenzo (a slaughterhouse worker with a famed hand for salting pork) his lady love, renaming her Dulcinea del Toboso.",
"title": "Summary"
},
{
"paragraph_id": 6,
"text": "As he travels in search of adventure, he arrives at an inn that he believes to be a castle, calls the prostitutes he meets there \"ladies\", and demands that the innkeeper, whom he takes to be the lord of the castle, dub him a knight. The innkeeper agrees. Quixote starts the night holding vigil at the inn's horse trough, which Quixote imagines to be a chapel. He then becomes involved in a fight with muleteers who try to remove his armor from the horse trough so that they can water their mules. In a pretended ceremony, the innkeeper dubs him a knight to be rid of him and sends him on his way.",
"title": "Summary"
},
{
"paragraph_id": 7,
"text": "Quixote encounters a servant named Andres who is tied to a tree and who is being beaten by his master over disputed wages. Quixote orders the master to stop beating Andres and untie him and makes the master swear to treat Andres fairly. However, the beating is resumed, and redoubled, as soon as Quixote leaves.",
"title": "Summary"
},
{
"paragraph_id": 8,
"text": "Quixote then encounters traders from Toledo. He challenges them to agree that Dulcinea del Toboso is the most beautiful woman in the world. One of them demands to see her picture so that he can decide for himself. Enraged, Quixote charges at them but his horse stumbles, causing him to fall. One of the traders beats up Quixote, who is left at the side of the road until a neighboring peasant brings him back home.",
"title": "Summary"
},
{
"paragraph_id": 9,
"text": "While Quixote lies unconscious in his bed, his niece, the housekeeper, the parish curate, and the local barber burn most of his chivalric and other books. They seal up the room which contained the library, later telling Quixote that it was done by a wizard.",
"title": "Summary"
},
{
"paragraph_id": 10,
"text": "Don Quixote asks his neighbour, the poor farm labourer Sancho Panza, to be his squire, promising him a petty governorship. Sancho agrees and they sneak away at dawn. Their adventures together begin with Quixote's attack on some windmills which he believes to be ferocious giants. They next encounter two Benedictine friars and, nearby, an unrelated lady in a carriage. Quixote takes the friars to be enchanters who are holding the lady captive, knocks one of them from his horse, and is challenged by an armed Basque travelling with the company. The combat ends with the lady leaving her carriage and commanding those travelling with her to \"surrender\" to Quixote.",
"title": "Summary"
},
{
"paragraph_id": 11,
"text": "After a friendly encounter with some goatherds and a less friendly one with some Yanguesan porters driving Galician ponies, Quixote and Sancho return to the \"castle\" (inn), where a mix-up involving a servant girl's romantic rendezvous with another guest results in a brawl. Quixote explains to Sancho that the castle is enchanted. They decide to leave, but Quixote, following the example of the fictional knights, leaves without paying. Sancho ends up wrapped in a blanket and tossed in the air by several mischievous guests at the inn before he manages to follow.",
"title": "Summary"
},
{
"paragraph_id": 12,
"text": "After further adventures involving a dead body, a legendary helmet (in Quixote's mind), and a group of galley slaves, they wander into the Sierra Morena. There they encounter the dejected and mostly mad Cardenio, who relates his story. Quixote decides to imitate Cardenio and live like a hermit. He sends Sancho to deliver a letter to Dulcinea, but instead Sancho finds the barber and priest from his village. They make a plan to trick Quixote into coming home, recruiting Dorotea, a woman they discover in the forest, to pose as the Princess Micomicona, a damsel in distress.",
"title": "Summary"
},
{
"paragraph_id": 13,
"text": "The plan works and Quixote and the group return to the inn, though Quixote is now convinced, thanks to a lie told by Sancho when asked about the letter, that Dulcinea wants to see him. At the inn, several other plots intersect and are resolved. Meanwhile, a sleepwalking Quixote does battle with some wineskins which he takes to be the giant who stole the princess Micomicona's kingdom. An officer of the Santa Hermandad arrives with a warrant for Quixote's arrest for freeing the galley slaves, but the priest begs for the officer to have mercy on account of Quixote's insanity. The officer agrees and Quixote is locked in a cage which he is made to think is an enchantment. He has a learned conversation with a Toledo canon he encounters by chance on the road, in which the canon expresses his scorn for untruthful chivalric books, but Don Quixote defends them. The group stops to eat and lets Quixote out of the cage; he gets into a fight with a goatherd and with a group of pilgrims, who beat him into submission, before he is finally brought home.",
"title": "Summary"
},
{
"paragraph_id": 14,
"text": "The narrator ends the story by saying that he has found manuscripts of Quixote's further adventures.",
"title": "Summary"
},
{
"paragraph_id": 15,
"text": "Although the two parts are now published as a single work, Don Quixote, Part Two was a sequel published ten years after the original novel. In an early example of metafiction, Part Two assumes that several of its characters have read the first part of the novel and are thus familiar with the history and peculiarities of the two protagonists.",
"title": "Summary"
},
{
"paragraph_id": 16,
"text": "Don Quixote and Sancho are on their way to El Toboso to meet Dulcinea, with Sancho aware that his story about Dulcinea was a complete fabrication. They reach the city at daybreak and decide to enter at nightfall. However, a bad omen frightens Quixote into retreat and they quickly leave. Sancho is instead sent out alone by Quixote to meet Dulcinea and act as a go-between. Sancho's luck brings three peasant girls along the road and he quickly tells Quixote that they are Dulcinea and her ladies-in-waiting and as beautiful as ever. Since Quixote only sees the peasant girls, Sancho goes on to pretend that an enchantment of some sort is at work.",
"title": "Summary"
},
{
"paragraph_id": 17,
"text": "A duke and duchess encounter the duo. These nobles have read Part One of the story and are themselves very fond of books of chivalry. They decide to play along for their own amusement, beginning a string of imagined adventures and practical jokes. As part of one prank, Quixote and Sancho are led to believe that the only way to release Dulcinea from her spell is for Sancho to give himself three thousand three hundred lashes. Sancho naturally resists this course of action, leading to friction with his master. Under the duke's patronage, Sancho eventually gets his promised governorship, though it is false, and he proves to be a wise and practical ruler before all ends in humiliation. Near the end, Don Quixote reluctantly sways towards sanity.",
"title": "Summary"
},
{
"paragraph_id": 18,
"text": "Quixote battles the Knight of the White Moon (a young man from Quixote's hometown who had earlier posed as the Knight of Mirrors) on the beach in Barcelona. Defeated, Quixote submits to prearranged chivalric terms: the vanquished must obey the will of the conqueror. He is ordered to lay down his arms and cease his acts of chivalry for a period of one year, by which time his friends and relatives hope he will be cured.",
"title": "Summary"
},
{
"paragraph_id": 19,
"text": "On the way back home, Quixote and Sancho \"resolve\" the disenchantment of Dulcinea. Upon returning to his village, Quixote announces his plan to retire to the countryside as a shepherd, but his housekeeper urges him to stay at home. Soon after, he retires to his bed with a deathly illness, and later awakes from a dream, having fully become Alonso Quixano once more. Sancho tries to restore his faith and his interest in Dulcinea, but Quixano only renounces his previous ambition and apologizes for the harm he has caused. He dictates his will, which includes a provision that his niece will be disinherited if she marries a man who reads books of chivalry.",
"title": "Summary"
},
{
"paragraph_id": 20,
"text": "After Quixano dies, the author emphasizes that there are no more adventures to relate and that any further books about Don Quixote would be spurious.",
"title": "Summary"
},
{
"paragraph_id": 21,
"text": "Don Quixote, Part One contains a number of stories which do not directly involve the two main characters, but which are narrated by some of the picaresque figures encountered by the Don and Sancho during their travels. The longest and best known of these is \"El Curioso Impertinente\" (The Ill-Advised Curiosity), found in Part One, Book Four. This story, read to a group of travelers at an inn, tells of a Florentine nobleman, Anselmo, who becomes obsessed with testing his wife's fidelity and talks his close friend Lothario into attempting to seduce her, with disastrous results for all.",
"title": "Summary"
},
{
"paragraph_id": 22,
"text": "In Part Two, the author acknowledges the criticism of his digressions in Part One and promises to concentrate the narrative on the central characters (although at one point he laments that his narrative muse has been constrained in this manner). Nevertheless, \"Part Two\" contains several back narratives related by peripheral characters.",
"title": "Summary"
},
{
"paragraph_id": 23,
"text": "Several abridged editions have been published which delete some or all of the extra tales in order to concentrate on the central narrative.",
"title": "Summary"
},
{
"paragraph_id": 24,
"text": "The story within a story relates that, for no particular reason, Anselmo decides to test the fidelity of his wife, Camilla, and asks his friend, Lothario, to seduce her. Thinking that to be madness, Lothario reluctantly agrees, and soon reports to Anselmo that Camilla is a faithful wife. Anselmo learns that Lothario has lied and attempted no seduction. He makes Lothario promise to try in earnest and leaves town to make this easier. Lothario tries and Camilla writes letters to her husband telling him of the attempts by Lothario and asking him to return. Anselmo makes no reply and does not return. Lothario then falls in love with Camilla, who eventually reciprocates; an affair between them ensues, but is not disclosed to Anselmo, and their affair continues after Anselmo returns.",
"title": "Summary"
},
{
"paragraph_id": 25,
"text": "One day, Lothario sees a man leaving Camilla's house and jealously presumes she has taken another lover. He tells Anselmo that, at last, he has been successful and arranges a time and place for Anselmo to see the seduction. Before this rendezvous, however, Lothario learns that the man was the lover of Camilla's maid. He and Camilla then contrive to deceive Anselmo further: When Anselmo watches them, she refuses Lothario, protests her love for her husband, and stabs herself lightly in the breast. Anselmo is reassured of her fidelity. The affair restarts with Anselmo none the wiser.",
"title": "Summary"
},
{
"paragraph_id": 26,
"text": "Later, the maid's lover is discovered by Anselmo. Fearing that Anselmo will kill her, the maid says she will tell Anselmo a secret the next day. Anselmo tells Camilla that this is to happen, and Camilla expects that her affair is to be revealed. Lothario and Camilla flee that night. The maid flees the next day. Anselmo searches for them in vain before learning from a stranger of his wife's affair. He starts to write the story, but dies of grief before he can finish. Lothario is killed in battle soon afterward and Camilla dies of grief.",
"title": "Summary"
},
{
"paragraph_id": 27,
"text": "The novel's farcical elements make use of punning and similar verbal playfulness. Character-naming in Don Quixote makes ample figural use of contradiction, inversion, and irony, such as the names Rocinante (a reversal) and Dulcinea (an allusion to illusion), and the word quixote itself, possibly a pun on quijada (jaw) but certainly cuixot (Catalan: thighs), a reference to a horse's rump.",
"title": "Style and interpretations"
},
{
"paragraph_id": 28,
"text": "As a military term, the word quijote refers to cuisses, part of a full suit of plate armour protecting the thighs. The Spanish suffix -ote denotes the augmentative—for example, grande means large, but grandote means extra large, with grotesque connotations. Following this example, Quixote would suggest 'The Great Quijano', an oxymoronic play on words that makes much sense in light of the character's delusions of grandeur.",
"title": "Style and interpretations"
},
{
"paragraph_id": 29,
"text": "Cervantes wrote his work in Early Modern Spanish, heavily borrowing from Old Spanish, the medieval form of the language. The language of Don Quixote, although still containing archaisms, is far more understandable to modern Spanish readers than is, for instance, the completely medieval Spanish of the Poema de mio Cid, a kind of Spanish that is as different from Cervantes' language as Middle English is from Modern English. The Old Castilian language was also used to show the higher class that came with being a knight errant.",
"title": "Style and interpretations"
},
{
"paragraph_id": 30,
"text": "In Don Quixote, there are basically two different types of Castilian: Old Castilian is spoken only by Don Quixote, while the rest of the roles speak a contemporary (late 16th century) version of Spanish. The Old Castilian of Don Quixote is a humoristic resource—he copies the language spoken in the chivalric books that made him mad; and many times, when he talks nobody is able to understand him because his language is too old. This humorous effect is more difficult to see nowadays because the reader must be able to distinguish the two old versions of the language, but when the book was published it was much celebrated. (English translations can get some sense of the effect by having Don Quixote use King James Bible or Shakespearean English, or even Middle English.)",
"title": "Style and interpretations"
},
{
"paragraph_id": 31,
"text": "In Old Castilian, the letter x represented the sound written sh in modern English, so the name was originally pronounced [kiˈʃote]. However, as Old Castilian evolved towards modern Spanish, a sound change caused it to be pronounced with a voiceless velar fricative [x] sound (like the Scots or German ch), and today the Spanish pronunciation of \"Quixote\" is [kiˈxote]. The original pronunciation is reflected in languages such as Asturian, Leonese, Galician, Catalan, Italian, Portuguese, Turkish and French, where it is pronounced with a \"sh\" or \"ch\" sound; the French opera Don Quichotte is one of the best-known modern examples of this pronunciation.",
"title": "Style and interpretations"
},
{
"paragraph_id": 32,
"text": "Today, English speakers generally attempt something close to the modern Spanish pronunciation of Quixote (Quijote), as /kiːˈhoʊti/, although the traditional English spelling-based pronunciation with the value of the letter x in modern English is still sometimes used, resulting in /ˈkwɪksət/ or /ˈkwɪksoʊt/. In Australian English, the preferred pronunciation amongst members of the educated classes was /ˈkwɪksət/ until well into the 1970s, as part of a tendency for the upper class to \"anglicise its borrowing ruthlessly\". The traditional English rendering is preserved in the pronunciation of the adjectival form quixotic, i.e., /kwɪkˈsɒtɪk/, defined by Merriam-Webster as the foolishly impractical pursuit of ideals, typically marked by rash and lofty romanticism.",
"title": "Style and interpretations"
},
{
"paragraph_id": 33,
"text": "Harold Bloom says Don Quixote is the first modern novel, and that the protagonist is at war with Freud's reality principle, which accepts the necessity of dying. Bloom says that the novel has an endless range of meanings, but that a recurring theme is the human need to withstand suffering.",
"title": "Style and interpretations"
},
{
"paragraph_id": 34,
"text": "Edith Grossman, who wrote and published a highly acclaimed English translation of the novel in 2003, says that the book is mostly meant to move people into emotion using a systematic change of course, on the verge of both tragedy and comedy at the same time. Grossman has stated:",
"title": "Style and interpretations"
},
{
"paragraph_id": 35,
"text": "The question is that Quixote has multiple interpretations [...] and how do I deal with that in my translation. I'm going to answer your question by avoiding it [...] so when I first started reading the Quixote I thought it was the most tragic book in the world, and I would read it and weep [...] As I grew older [...] my skin grew thicker [...] and so when I was working on the translation I was actually sitting at my computer and laughing out loud. This is done [...] as Cervantes did it [...] by never letting the reader rest. You are never certain that you truly got it. Because as soon as you think you understand something, Cervantes introduces something that contradicts your premise.",
"title": "Style and interpretations"
},
{
"paragraph_id": 36,
"text": "The novel's structure is episodic in form. The full title is indicative of the tale's object, as ingenioso (Spanish) means \"quick with inventiveness\", marking the transition of modern literature from dramatic to thematic unity. The novel takes place over a long period of time, including many adventures united by common themes of the nature of reality, reading, and dialogue in general.",
"title": "Style and interpretations"
},
{
"paragraph_id": 37,
"text": "Although burlesque on the surface, the novel, especially in its second half, has served as an important thematic source not only in literature but also in much of art and music, inspiring works by Pablo Picasso and Richard Strauss. The contrasts between the tall, thin, fancy-struck and idealistic Quixote and the fat, squat, world-weary Panza is a motif echoed ever since the book's publication, and Don Quixote's imaginings are the butt of outrageous and cruel practical jokes in the novel.",
"title": "Style and interpretations"
},
{
"paragraph_id": 38,
"text": "Even faithful and simple Sancho is forced to deceive him at certain points. The novel is considered a satire of orthodoxy, veracity and even nationalism. In exploring the individualism of his characters, Cervantes helped lead literary practice beyond the narrow convention of the chivalric romance. He spoofs the chivalric romance through a straightforward retelling of a series of acts that redound to the knightly virtues of the hero. The character of Don Quixote became so well known in its time that the word quixotic was quickly adopted by many languages. Characters such as Sancho Panza and Don Quixote's steed, Rocinante, are emblems of Western literary culture. The phrase \"tilting at windmills\" to describe an act of attacking imaginary enemies (or an act of extreme idealism), derives from an iconic scene in the book.",
"title": "Style and interpretations"
},
{
"paragraph_id": 39,
"text": "It stands in a unique position between medieval romance and the modern novel. The former consists of disconnected stories featuring the same characters and settings with little exploration of the inner life of even the main character. The latter are usually focused on the psychological evolution of their characters. In Part I, Quixote imposes himself on his environment. By Part II, people know about him through \"having read his adventures\", and so, he needs to do less to maintain his image. By his deathbed, he has regained his sanity, and is once more \"Alonso Quixano the Good\".",
"title": "Style and interpretations"
},
{
"paragraph_id": 40,
"text": "Sources for Don Quixote include the Castilian novel Amadis de Gaula, which had enjoyed great popularity throughout the 16th century. Another prominent source, which Cervantes evidently admires more, is Tirant lo Blanch, which the priest describes in Chapter VI of Quixote as \"the best book in the world.\" (However, the sense in which it was \"best\" is much debated among scholars. Since the 19th century, the passage has been called \"the most difficult passage of Don Quixote\".) The scene of the book burning gives an excellent list of Cervantes's likes and dislikes about literature.",
"title": "Background"
},
{
"paragraph_id": 41,
"text": "Cervantes makes a number of references to the Italian poem Orlando furioso. In chapter 10 of the first part of the novel, Don Quixote says he must take the magical helmet of Mambrino, an episode from Canto I of Orlando, and itself a reference to Matteo Maria Boiardo's Orlando innamorato. The interpolated story in chapter 33 of Part four of the First Part is a retelling of a tale from Canto 43 of Orlando, regarding a man who tests the fidelity of his wife.",
"title": "Background"
},
{
"paragraph_id": 42,
"text": "Another important source appears to have been Apuleius's The Golden Ass, one of the earliest known novels, a picaresque from late classical antiquity. The wineskins episode near the end of the interpolated tale \"The Curious Impertinent\" in chapter 35 of the first part of Don Quixote is a clear reference to Apuleius, and recent scholarship suggests that the moral philosophy and the basic trajectory of Apuleius's novel are fundamental to Cervantes' program. Similarly, many of both Sancho's adventures in Part II and proverbs throughout are taken from popular Spanish and Italian folklore.",
"title": "Background"
},
{
"paragraph_id": 43,
"text": "Cervantes' experiences as a galley slave in Algiers also influenced Quixote.",
"title": "Background"
},
{
"paragraph_id": 44,
"text": "Medical theories may have also influenced Cervantes' literary process. Cervantes had familial ties to the distinguished medical community. His father, Rodrigo de Cervantes, and his great-grandfather, Juan Díaz de Torreblanca, were surgeons. Additionally, his sister, Andrea de Cervantes, was a nurse. He also befriended many individuals involved in the medical field, in that he knew medical author Francisco Díaz, an expert in urology, and royal doctor Antonio Ponce de Santa Cruz who served as a personal doctor to both Philip III and Philip IV of Spain.",
"title": "Background"
},
{
"paragraph_id": 45,
"text": "Apart from the personal relations Cervantes maintained within the medical field, Cervantes' personal life was defined by an interest in medicine. He frequently visited patients from the Hospital de Inocentes in Sevilla. Furthermore, Cervantes explored medicine in his personal library. His library contained more than 200 volumes and included books like Examen de Ingenios, by Juan Huarte and Practica y teórica de cirugía, by Dionisio Daza Chacón that defined medical literature and medical theories of his time.",
"title": "Background"
},
{
"paragraph_id": 46,
"text": "Researchers Isabel Sanchez Duque and Francisco Javier Escudero have found that Cervantes was a friend of the family Villaseñor, which was involved in a combat with Francisco de Acuña. Both sides combated disguised as medieval knights in the road from El Toboso to Miguel Esteban in 1581. They also found a person called Rodrigo Quijada, who bought the title of nobility of \"hidalgo\", and created diverse conflicts with the help of a squire.",
"title": "Background"
},
{
"paragraph_id": 47,
"text": "It is not certain when Cervantes began writing Part Two of Don Quixote, but he had probably not proceeded much further than Chapter LIX by late July 1614. In about September, however, a spurious Part Two, entitled Second Volume of the Ingenious Gentleman Don Quixote of La Mancha: by the Licenciado (doctorate) Alonso Fernández de Avellaneda, of Tordesillas, was published in Tarragona by an unidentified Aragonese who was an admirer of Lope de Vega, rival of Cervantes. It was translated into English by William Augustus Yardley, Esquire in two volumes in 1784.",
"title": "Background"
},
{
"paragraph_id": 48,
"text": "Some modern scholars suggest that Don Quixote's fictional encounter with Avellaneda's book in Chapter 59 of Part II should not be taken as the date that Cervantes encountered it, which may have been much earlier.",
"title": "Background"
},
{
"paragraph_id": 49,
"text": "Avellaneda's identity has been the subject of many theories, but there is no consensus as to who he was. In its prologue, the author gratuitously insulted Cervantes, who took offense and responded; the last half of Chapter LIX and most of the following chapters of Cervantes's Segunda Parte lend some insight into the effects upon him; Cervantes manages to work in some subtle digs at Avellaneda's own work, and in his preface to Part II, comes very near to criticizing Avellaneda directly.",
"title": "Background"
},
{
"paragraph_id": 50,
"text": "In his introduction to The Portable Cervantes, Samuel Putnam, a noted translator of Cervantes' novel, calls Avellaneda's version \"one of the most disgraceful performances in history\".",
"title": "Background"
},
{
"paragraph_id": 51,
"text": "The second part of Cervantes' Don Quixote, finished as a direct result of the Avellaneda book, has come to be regarded by some literary critics as superior to the first part, because of its greater depth of characterization, its discussions, mostly between Quixote and Sancho, on diverse subjects, and its philosophical insights. In Cervantes's Segunda Parte, Don Quixote visits a printing-house in Barcelona and finds Avellaneda's Second Part being printed there, in an early example of metafiction. Don Quixote and Sancho Panza also meet one of the characters from Avellaneda's book, Don Alvaro Tarfe, and make him swear that the “other” Quixote and Sancho are impostors.",
"title": "Background"
},
{
"paragraph_id": 52,
"text": "Cervantes' story takes place on the plains of La Mancha, specifically the comarca of Campo de Montiel.",
"title": "Background"
},
{
"paragraph_id": 53,
"text": "En un lugar de La Mancha, de cuyo nombre no quiero acordarme, no ha mucho tiempo que vivía un hidalgo de los de lanza en astillero, adarga antigua, rocín flaco y galgo corredor.(Somewhere in La Mancha, in a place whose name I do not care to remember, a gentleman lived not long ago, one of those who has a lance and ancient shield on a shelf and keeps a skinny nag and a greyhound for racing.)",
"title": "Background"
},
{
"paragraph_id": 54,
"text": "The location of the village to which Cervantes alludes in the opening sentence of Don Quixote has been the subject of debate since its publication over four centuries ago. Indeed, Cervantes deliberately omits the name of the village, giving an explanation in the final chapter:",
"title": "Background"
},
{
"paragraph_id": 55,
"text": "Such was the end of the Ingenious Gentleman of La Mancha, whose village Cide Hamete would not indicate precisely, in order to leave all the towns and villages of La Mancha to contend among themselves for the right to adopt him and claim him as a son, as the seven cities of Greece contended for Homer.",
"title": "Background"
},
{
"paragraph_id": 56,
"text": "In 2004, a multidisciplinary team of academics from Complutense University, led by Francisco Parra Luna, Manuel Fernández Nieto, and Santiago Petschen Verdaguer, deduced that the village was that of Villanueva de los Infantes. Their findings were published in a paper titled \"'El Quijote' como un sistema de distancias/tiempos: hacia la localización del lugar de la Mancha\", which was later published as a book: El enigma resuelto del Quijote. The result was replicated in two subsequent investigations: \"La determinación del lugar de la Mancha como problema estadístico\" and \"The Kinematics of the Quixote and the Identity of the 'Place in La Mancha'\".",
"title": "Background"
},
{
"paragraph_id": 57,
"text": "Translators of Don Quixote, such as John Ormsby, have commented that the region of La Mancha is one of the most desertlike, unremarkable regions of Spain, the least romantic and fanciful place that one would imagine as the home of a courageous knight.",
"title": "Background"
},
{
"paragraph_id": 58,
"text": "On the other hand, as Borges points out:",
"title": "Background"
},
{
"paragraph_id": 59,
"text": "I suspect that in Don Quixote, it does not rain a single time. The landscapes described by Cervantes have nothing in common with the landscapes of Castile: they are conventional landscapes, full of meadows, streams, and copses that belong in an Italian novel.",
"title": "Background"
},
{
"paragraph_id": 60,
"text": "The story also takes place in El Toboso where Don Quixote goes to seek Dulcinea's blessings.",
"title": "Background"
},
{
"paragraph_id": 61,
"text": "Don Quixote is said to reflect the Spanish society in which Cervantes lived and wrote. Spain's status as a world power was declining, and the Spanish national treasury was bankrupt due to expensive foreign wars. Spanish cultural dominance was also waning as the Protestant Reformation had put the Spanish Roman Catholic Church on the defensive, which had led to the establishment of the Spanish Inquisition. Meanwhile, the hidalgo class was losing relevance because of changes in Spanish society which made the high ideals of chivalry obsolete.",
"title": "Background"
},
{
"paragraph_id": 62,
"text": "Don Quixote continues to be the origin of replication for authors. In 2002 the Norwegian Nobel Institute conducted a study among writers from 55 countries, the majority voted Don Quixote \"the greatest work of fiction ever written\".",
"title": "Legacy"
},
{
"paragraph_id": 63,
"text": "The opening sentence of the book created a classic Spanish cliché with the phrase de cuyo nombre no quiero acordarme (\"whose name I do not wish to recall\"): En un lugar de la Mancha, de cuyo nombre no quiero acordarme, no hace mucho tiempo que vivía un hidalgo de los de lanza en astillero, adarga antigua, rocín flaco y galgo corredor. (\"In a village of La Mancha, whose name I do not wish to recall, there lived, not very long ago, one of those gentlemen with a lance in the lance-rack, an ancient shield, a skinny old horse, and a fast greyhound.\")",
"title": "Legacy"
},
{
"paragraph_id": 64,
"text": "Don Quixote alongside its many translations, has also provided a number of idioms and expressions to the English language. Examples with their own articles include the phrase \"the pot calling the kettle black\" and the adjective \"quixotic.\"",
"title": "Legacy"
},
{
"paragraph_id": 65,
"text": "Tilting at windmills is an English idiom that means \"attacking imaginary enemies\". The expression is derived from Don Quixote, and the word \"tilt\" in this context refers to jousting. This phrase is sometimes also expressed as \"charging at windmills\" or \"fighting the windmills\".",
"title": "Legacy"
},
{
"paragraph_id": 66,
"text": "The phrase is sometimes used to describe either confrontations where adversaries are incorrectly perceived, or courses of action that are based on misinterpreted or misapplied heroic, romantic, or idealistic justifications. It may also connote an inopportune, unfounded, and vain effort against adversaries real or imagined.",
"title": "Legacy"
},
{
"paragraph_id": 67,
"text": "In July 1604, Cervantes sold the rights of El ingenioso hidalgo don Quixote de la Mancha (known as Don Quixote, Part I) to the publisher-bookseller Francisco de Robles for an unknown sum. License to publish was granted in September, the printing was finished in December, and the book came out on 16 January 1605.",
"title": "Publication"
},
{
"paragraph_id": 68,
"text": "The novel was an immediate success. Most of the 400 copies of the first edition were sent to the New World, with the publisher hoping to get a better price in the Americas. Although most of them disappeared in a shipwreck near La Havana, approximately 70 copies reached Lima, from where they were sent to Cuzco, in the heart of the defunct Inca Empire.",
"title": "Publication"
},
{
"paragraph_id": 69,
"text": "No sooner was it in the hands of the public than preparations were made to issue derivative (pirated) editions. In 1614 a fake second part was published by a mysterious author under the pen name Avellaneda. This author was never satisfactorily identified. This rushed Cervantes into writing and publishing a genuine second part in 1615, which was a year before his own death. Don Quixote had been growing in favour, and its author's name was now known beyond the Pyrenees. By August 1605, there were two Madrid editions, two published in Lisbon, and one in Valencia. Publisher Francisco de Robles secured additional copyrights for Aragon and Portugal for a second edition.",
"title": "Publication"
},
{
"paragraph_id": 70,
"text": "Sale of these publishing rights deprived Cervantes of further financial profit on Part One. In 1607, an edition was printed in Brussels. Robles, the Madrid publisher, found it necessary to meet demand with a third edition, a seventh publication in all, in 1608. Popularity of the book in Italy was such that a Milan bookseller issued an Italian edition in 1610. Yet another Brussels edition was called for in 1611. Since then, numerous editions have been released and in total, the novel is believed to have sold more than 500 million copies worldwide. The work has been produced in numerous editions and languages, the Cervantes Collection, at the State Library of New South Wales includes over 1,100 editions. These were collected, by Ben Haneman, over a period of thirty years.",
"title": "Publication"
},
{
"paragraph_id": 71,
"text": "In 1613, Cervantes published the Novelas ejemplares, dedicated to the Maecenas of the day, the Conde de Lemos. Eight and a half years after Part One had appeared came the first hint of a forthcoming Segunda Parte (Part Two). \"You shall see shortly\", Cervantes says, \"the further exploits of Don Quixote and humours of Sancho Panza.\" Don Quixote, Part Two, published by the same press as its predecessor, appeared late in 1615, and quickly reprinted in Brussels and Valencia (1616) and Lisbon (1617). Parts One and Two were published as one edition in Barcelona in 1617. Historically, Cervantes' work has been said to have \"smiled Spain's chivalry away\", suggesting that Don Quixote as a chivalric satire contributed to the demise of Spanish Chivalry.",
"title": "Publication"
},
{
"paragraph_id": 72,
"text": "There are many translations of the book, and it has been adapted many times in shortened versions. Many derivative editions were also written at the time, as was the custom of envious or unscrupulous writers. Seven years after the Parte Primera appeared, Don Quixote had been translated into French, German, Italian, and English, with the first French translation of 'Part II' appearing in 1618, and the first English translation in 1620. One abridged adaptation, authored by Agustín Sánchez, runs slightly over 150 pages, cutting away about 750 pages.",
"title": "Publication"
},
{
"paragraph_id": 73,
"text": "Thomas Shelton's English translation of the First Part appeared in 1612 while Cervantes was still alive, although there is no evidence that Shelton had met the author. Although Shelton's version is cherished by some, according to John Ormsby and Samuel Putnam, it was far from satisfactory as a carrying over of Cervantes' text. Shelton's translation of the novel's Second Part appeared in 1620.",
"title": "Publication"
},
{
"paragraph_id": 74,
"text": "Near the end of the 17th century, John Phillips, a nephew of poet John Milton, published what Putnam considered the worst English translation. The translation, as literary critics claim, was not based on Cervantes' text but mostly on a French work by Filleau de Saint-Martin and on notes which Thomas Shelton had written.",
"title": "Publication"
},
{
"paragraph_id": 75,
"text": "Around 1700, a version by Pierre Antoine Motteux appeared. Motteux's translation enjoyed lasting popularity; it was reprinted as the Modern Library Series edition of the novel until recent times. Nonetheless, future translators would find much to fault in Motteux's version: Samuel Putnam criticized \"the prevailing slapstick quality of this work, especially where Sancho Panza is involved, the obtrusion of the obscene where it is found in the original, and the slurring of difficulties through omissions or expanding upon the text\". John Ormsby considered Motteux's version \"worse than worthless\", and denounced its \"infusion of Cockney flippancy and facetiousness\" into the original.",
"title": "Publication"
},
{
"paragraph_id": 76,
"text": "The proverb \"The proof of the pudding is in the eating\" is widely attributed to Cervantes. The Spanish word for pudding (budín), however, does not appear in the original text but premieres in the Motteux translation. In Smollett's translation of 1755 he notes that the original text reads literally \"you will see when the eggs are fried\", meaning \"time will tell\".",
"title": "Publication"
},
{
"paragraph_id": 77,
"text": "A translation by Captain John Stevens, which revised Thomas Shelton's version, also appeared in 1700, but its publication was overshadowed by the simultaneous release of Motteux's translation.",
"title": "Publication"
},
{
"paragraph_id": 78,
"text": "In 1742, the Charles Jervas translation appeared, posthumously. Through a printer's error, it came to be known, and is still known, as \"the Jarvis translation\". It was the most scholarly and accurate English translation of the novel up to that time, but future translator John Ormsby points out in his own introduction to the novel that the Jarvis translation has been criticized as being too stiff. Nevertheless, it became the most frequently reprinted translation of the novel until about 1885. Another 18th-century translation into English was that of Tobias Smollett, himself a novelist, first published in 1755. Like the Jarvis translation, it continues to be reprinted today.",
"title": "Publication"
},
{
"paragraph_id": 79,
"text": "A translation by Alexander James Duffield appeared in 1881 and another by Henry Edward Watts in 1888. Most modern translators take as their model the 1885 translation by John Ormsby.",
"title": "Publication"
},
{
"paragraph_id": 80,
"text": "An expurgated children's version, under the title The Story of Don Quixote, was published in 1922 (available on Project Gutenberg). It leaves out the risqué sections as well as chapters that young readers might consider dull, and embellishes a great deal on Cervantes' original text. The title page actually gives credit to the two editors as if they were the authors, and omits any mention of Cervantes.",
"title": "Publication"
},
{
"paragraph_id": 81,
"text": "The most widely read English-language translations of the mid-20th century are by Samuel Putnam (1949), J. M. Cohen (1950; Penguin Classics), and Walter Starkie (1957). The last English translation of the novel in the 20th century was by Burton Raffel, published in 1996. The 21st century has already seen five new translations of the novel into English. The first is by John D. Rutherford and the second by Edith Grossman. Reviewing the novel in The New York Times, Carlos Fuentes called Grossman's translation a \"major literary achievement\" and another called it the \"most transparent and least impeded among more than a dozen English translations going back to the 17th century.\"",
"title": "Publication"
},
{
"paragraph_id": 82,
"text": "In 2005, the year of the novel's 400th anniversary, Tom Lathrop published a new English translation of the novel, based on a lifetime of specialized study of the novel and its history. The fourth translation of the 21st century was released in 2006 by former university librarian James H. Montgomery, 26 years after he had begun it, in an attempt to \"recreate the sense of the original as closely as possible, though not at the expense of Cervantes' literary style.\"",
"title": "Publication"
},
{
"paragraph_id": 83,
"text": "In 2011, another translation by Gerald J. Davis appeared. It is the latest and the fifth translation of the 21st century, though it is self published via Lulu.com.",
"title": "Publication"
},
{
"paragraph_id": 84,
"text": "Reviewing the English translations as a whole, Daniel Eisenberg stated that there is no one translation ideal for every purpose, but expressed a preference for those of Putnam and the revision of Ormsby's translation by Douglas and Jones.",
"title": "List of English translations"
}
] | Don Quixote is a Spanish epic novel by Miguel de Cervantes. It was originally published in two parts, in 1605 and 1615. Considered a founding work of Western literature, it is often labelled as the first modern novel and one of the greatest works ever written. Don Quixote is also one of the most-translated books in the world and one of the best-selling novels of all time. The plot revolves around the adventures of a member of the lowest nobility, an hidalgo from La Mancha named Alonso Quijano, who reads so many chivalric romances that he loses his mind and decides to become a knight-errant to revive chivalry and serve his nation, under the name Don Quixote de la Mancha. He recruits as his squire a simple farm labourer, Sancho Panza, who brings a unique, earthy wit to Don Quixote's lofty rhetoric. In the first part of the book, Don Quixote does not see the world for what it is and prefers to imagine that he is living out a knightly story meant for the annals of all time. However, as Salvador de Madariaga pointed out in his Guía del lector del Quijote, referring to "the Sanchification of Don Quixote and the Quixotization of Sancho", as "Sancho's spirit ascends from reality to illusion, Don Quixote's declines from illusion to reality". The book had a major influence on the literary community, as evidenced by direct references in Alexandre Dumas' The Three Musketeers (1844), and Edmond Rostand's Cyrano de Bergerac (1897) as well as the word quixotic. Mark Twain referred to the book as having "swept the world's admiration for the mediaeval chivalry-silliness out of existence". | 2001-08-18T00:10:04Z | 2023-12-27T15:12:33Z | [
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] | https://en.wikipedia.org/wiki/Don_Quixote |
8,239 | Dylan | Dylan may refer to: | [
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] | Dylan may refer to: | 2001-10-30T20:29:42Z | 2023-11-12T14:23:08Z | [
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] | https://en.wikipedia.org/wiki/Dylan |
8,240 | Dada | Dada (/ˈdɑːdɑː/) or Dadaism was an art movement of the European avant-garde in the early 20th century, with early centres in Zürich, Switzerland, at the Cabaret Voltaire (in 1916), founded by Hugo Ball with his companion Emmy Hennings, and in Berlin in 1917. New York Dada began c. 1915, and after 1920 Dada flourished in Paris. Dadaist activities lasted until the mid 1920s.
Developed in reaction to World War I, the Dada movement consisted of artists who rejected the logic, reason, and aestheticism of modern capitalist society, instead expressing nonsense, irrationality, and anti-bourgeois protest in their works. The art of the movement began primarily as performance art, but eventually spanned visual, literary, and sound media, including collage, sound poetry, cut-up writing, and sculpture. Dadaist artists expressed their discontent toward violence, war, and nationalism and maintained political affinities with radical politics on the left-wing and far-left politics.
There is no consensus on the origin of the movement's name; a common story is that the German artist Richard Huelsenbeck slid a paper knife (letter-opener) at random into a dictionary, where it landed on "dada", a colloquial French term for a hobby horse. Jean Arp wrote that Tristan Tzara invented the word at 6 p.m. on 6 February 1916, in the Café de la Terrasse in Zürich. Others note that it suggests the first words of a child, evoking a childishness and absurdity that appealed to the group. Still others speculate that the word might have been chosen to evoke a similar meaning (or no meaning at all) in any language, reflecting the movement's internationalism.
The roots of Dada lie in pre-war avant-garde. The term anti-art, a precursor to Dada, was coined by Marcel Duchamp around 1913 to characterize works that challenge accepted definitions of art. Cubism and the development of collage and abstract art would inform the movement's detachment from the constraints of reality and convention. The work of French poets, Italian Futurists and the German Expressionists would influence Dada's rejection of the tight correlation between words and meaning. Works such as Ubu Roi (1896) by Alfred Jarry and the ballet Parade (1916–17) by Erik Satie would also be characterized as proto-Dadaist works. The Dada movement's principles were first collected in Hugo Ball's Dada Manifesto in 1916. Ball is seen as the founder of the Dada movement.
The Dadaist movement included public gatherings, demonstrations, and publication of art/literary journals; passionate coverage of art, politics, and culture were topics often discussed in a variety of media. Key figures in the movement included Jean Arp, Johannes Baader, Hugo Ball, Marcel Duchamp, Max Ernst, Elsa von Freytag-Loringhoven, George Grosz, Raoul Hausmann, John Heartfield, Emmy Hennings, Hannah Höch, Richard Huelsenbeck, Francis Picabia, Man Ray, Hans Richter, Kurt Schwitters, Sophie Taeuber-Arp, Tristan Tzara, and Beatrice Wood, among others. The movement influenced later styles like the avant-garde and downtown music movements, and groups including Surrealism, nouveau réalisme, pop art and Fluxus.
Dada was an informal international movement, with participants in Europe and North America. The beginnings of Dada correspond with the outbreak of World War I. For many participants, the movement was a protest against the bourgeois nationalist and colonialist interests, which many Dadaists believed were the root cause of the war, and against the cultural and intellectual conformity—in art and more broadly in society—that corresponded to the war.
Avant-garde circles outside France knew of pre-war Parisian developments. They had seen (or participated in) Cubist exhibitions held at Galeries Dalmau, Barcelona (1912), Galerie Der Sturm in Berlin (1912), the Armory Show in New York (1913), SVU Mánes in Prague (1914), several Jack of Diamonds exhibitions in Moscow and at Moderne Kunstkring, Amsterdam (between 1911 and 1915). Futurism developed in response to the work of various artists. Dada subsequently combined these approaches.
Many Dadaists believed that the 'reason' and 'logic' of bourgeois capitalist society had led people into war. They expressed their rejection of that ideology in artistic expression that appeared to reject logic and embrace chaos and irrationality. For example, George Grosz later recalled that his Dadaist art was intended as a protest "against this world of mutual destruction".
According to Hans Richter Dada was not art: it was "anti-art". Dada represented the opposite of everything which art stood for. Where art was concerned with traditional aesthetics, Dada ignored aesthetics. If art was to appeal to sensibilities, Dada was intended to offend.
Additionally, Dada attempted to reflect onto human perception and the chaotic nature of society. Tristan Tzara proclaimed, "Everything is Dada, too. Beware of Dada. Anti-dadaism is a disease: selfkleptomania, man's normal condition, is Dada. But the real Dadas are against Dada".
As Hugo Ball expressed it, "For us, art is not an end in itself ... but it is an opportunity for the true perception and criticism of the times we live in."
A reviewer from the American Art News stated at the time that "Dada philosophy is the sickest, most paralyzing and most destructive thing that has ever originated from the brain of man." Art historians have described Dada as being, in large part, a "reaction to what many of these artists saw as nothing more than an insane spectacle of collective homicide".
Years later, Dada artists described the movement as "a phenomenon bursting forth in the midst of the postwar economic and moral crisis, a savior, a monster, which would lay waste to everything in its path... [It was] a systematic work of destruction and demoralization... In the end it became nothing but an act of sacrilege."
To quote Dona Budd's The Language of Art Knowledge,
Dada was born out of negative reaction to the horrors of the First World War. This international movement was begun by a group of artists and poets associated with the Cabaret Voltaire in Zürich. Dada rejected reason and logic, prizing nonsense, irrationality and intuition. The origin of the name Dada is unclear; some believe that it is a nonsensical word. Others maintain that it originates from the Romanian artists Tristan Tzara's and Marcel Janco's frequent use of the words "da, da," meaning "yes, yes" in the Romanian language. Another theory says that the name "Dada" came during a meeting of the group when a paper knife stuck into a French–German dictionary happened to point to 'dada', a French word for 'hobbyhorse'.
The movement primarily involved visual arts, literature, poetry, art manifestos, art theory, theatre, and graphic design, and concentrated its anti-war politics through a rejection of the prevailing standards in art through anti-art cultural works.
The creations of Duchamp, Picabia, Man Ray, and others between 1915 and 1917 eluded the term Dada at the time, and "New York Dada" came to be seen as a post facto invention of Duchamp. At the outset of the 1920s the term Dada flourished in Europe with the help of Duchamp and Picabia, who had both returned from New York. Notwithstanding, Dadaists such as Tzara and Richter claimed European precedence. Art historian David Hopkins notes:
Ironically, though, Duchamp's late activities in New York, along with the machinations of Picabia, re-cast Dada's history. Dada's European chroniclers—primarily Richter, Tzara, and Huelsenbeck—would eventually become preoccupied with establishing the pre-eminence of Zurich and Berlin at the foundations of Dada, but it proved to be Duchamp who was most strategically brilliant in manipulating the genealogy of this avant-garde formation, deftly turning New York Dada from a late-comer into an originating force.
Dada emerged from a period of artistic and literary movements like Futurism, Cubism and Expressionism; centered mainly in Italy, France and Germany respectively, in those years. However, unlike the earlier movements Dada was able to establish a broad base of support, giving rise to a movement that was international in scope. Its adherents were based in cities all over the world including New York, Zürich, Berlin, Paris and others. There were regional differences like an emphasis on literature in Zürich and political protest in Berlin.
Prominent Dadaists published manifestos, but the movement was loosely organized and there was no central hierarchy. On 14 July 1916, Ball originated the seminal Dada Manifesto. Tzara wrote a second Dada manifesto, considered important Dada reading, which was published in 1918. Tzara's manifesto articulated the concept of "Dadaist disgust"—the contradiction implicit in avant-garde works between the criticism and affirmation of modernist reality. In the Dadaist perspective modern art and culture are considered a type of fetishization where the objects of consumption (including organized systems of thought like philosophy and morality) are chosen, much like a preference for cake or cherries, to fill a void.
The shock and scandal the movement inflamed was deliberate; Dadaist magazines were banned and their exhibits closed. Some of the artists even faced imprisonment. These provocations were part of the entertainment but, over time, audiences' expectations eventually outpaced the movement's capacity to deliver. As the artists' well-known "sarcastic laugh" started to come from the audience, the provocations of Dadaists began to lose their impact. Dada was an active movement during years of political turmoil from 1916 when European countries were actively engaged in World War I, the conclusion of which, in 1918, set the stage for a new political order.
There is some disagreement about where Dada originated. The movement is commonly accepted by most art historians and those who lived during this period to have identified with the Cabaret Voltaire (housed inside the Holländische Meierei bar in Zürich) co-founded by poet and cabaret singer Emmy Hennings and Hugo Ball. Some sources propose a Romanian origin, arguing that Dada was an offshoot of a vibrant artistic tradition that transposed to Switzerland when a group of Jewish modernist artists, including Tristan Tzara, Marcel Janco, and Arthur Segal settled in Zürich. Before World War I, similar art had already existed in Bucharest and other Eastern European cities; it is likely that Dada's catalyst was the arrival in Zürich of artists like Tzara and Janco.
The name Cabaret Voltaire was a reference to the French philosopher Voltaire, whose novel Candide mocked the religious and philosophical dogmas of the day. Opening night was attended by Ball, Tzara, Jean Arp, and Janco. These artists along with others like Sophie Taeuber, Richard Huelsenbeck and Hans Richter started putting on performances at the Cabaret Voltaire and using art to express their disgust with the war and the interests that inspired it.
Having left Germany and Romania during World War I, the artists arrived in politically neutral Switzerland. They used abstraction to fight against the social, political, and cultural ideas of that time. They used shock art, provocation, and "vaudevilleian excess" to subvert the conventions they believed had caused the Great War. The Dadaists believed those ideas to be a byproduct of bourgeois society that was so apathetic it would wage war against itself rather than challenge the status quo:
We had lost confidence in our culture. Everything had to be demolished. We would begin again after the tabula rasa. At the Cabaret Voltaire we began by shocking common sense, public opinion, education, institutions, museums, good taste, in short, the whole prevailing order.
Ball said that Janco's mask and costume designs, inspired by Romanian folk art, made "the horror of our time, the paralyzing background of events" visible. According to Ball, performances were accompanied by a "balalaika orchestra playing delightful folk-songs". Influenced by African music, arrhythmic drumming and jazz were common at Dada gatherings.
After the cabaret closed down, Dada activities moved on to a new gallery, and Hugo Ball left for Bern. Tzara began a relentless campaign to spread Dada ideas. He bombarded French and Italian artists and writers with letters, and soon emerged as the Dada leader and master strategist. The Cabaret Voltaire re-opened, and is still in the same place at the Spiegelgasse 1 in the Niederdorf.
Zürich Dada, with Tzara at the helm, published the art and literature review Dada beginning in July 1917, with five editions from Zürich and the final two from Paris.
Other artists, such as André Breton and Philippe Soupault, created "literature groups to help extend the influence of Dada".
After the fighting of the First World War had ended in the armistice of November 1918, most of the Zürich Dadaists returned to their home countries, and some began Dada activities in other cities. Others, such as the Swiss native Sophie Taeuber, would remain in Zürich into the 1920s.
"Berlin was a city of tightened stomachers, of mounting, thundering hunger, where hidden rage was transformed into a boundless money lust, and men's minds were concentrating more and more on questions of naked existence... Fear was in everybody's bones" – Richard Hülsenbeck
Raoul Hausmann, who helped establish Dada in Berlin, published his manifesto Synthethic Cino of Painting in 1918 where he attacked Expressionism and the art critics who promoted it. Dada is envisioned in contrast to art forms, such as Expressionism, that appeal to viewers' emotional states: "the exploitation of so-called echoes of the soul". In Hausmann's conception of Dada, new techniques of creating art would open doors to explore new artistic impulses. Fragmented use of real world stimuli allowed an expression of reality that was radically different from other forms of art:
A child's discarded doll or a brightly colored rag are more necessary expressions than those of some ass who seeks to immortalize himself in oils in finite parlors.
The groups in Germany were not as strongly anti-art as other groups. Their activity and art were more political and social, with corrosive manifestos and propaganda, satire, public demonstrations and overt political activities. The intensely political and war-torn environment of Berlin had a dramatic impact on the ideas of Berlin Dadaists. Conversely, New York's geographic distance from the war spawned its more theoretically-driven, less political nature. According to Hans Richter, a Dadaist who was in Berlin yet “aloof from active participation in Berlin Dada”, several distinguishing characteristics of the Dada movement there included: “its political element and its technical discoveries in painting and literature”; “inexhaustible energy”; “mental freedom which included the abolition of everything”; and “members intoxicated with their own power in a way that had no relation to the real world”, who would “turn their rebelliousness even against each other”.
In February 1918, while the Great War was approaching its climax, Huelsenbeck gave his first Dada speech in Berlin, and he produced a Dada manifesto later in the year. Following the October Revolution in Russia, by then out of the war, Hannah Höch and George Grosz used Dada to express communist sympathies. Grosz, together with John Heartfield, Höch and Hausmann developed the technique of photomontage during this period. Johannes Baader, the uninhibited Oberdada, was the “crowbar” of the Berlin movement's direct action according to Hans Richter and is credited with creating the first giant collages, according to Raoul Hausmann.
After the war, the artists published a series of short-lived political magazines and held the First International Dada Fair, 'the greatest project yet conceived by the Berlin Dadaists', in the summer of 1920. As well as work by the main members of Berlin Dada – Grosz, Raoul Hausmann, Hannah Höch, Johannes Baader, Huelsenbeck and Heartfield – the exhibition also included the work of Otto Dix, Francis Picabia, Jean Arp, Max Ernst, Rudolf Schlichter, Johannes Baargeld and others. In all, over 200 works were exhibited, surrounded by incendiary slogans, some of which also ended up written on the walls of the Nazi's Entartete Kunst exhibition in 1937. Despite high ticket prices, the exhibition lost money, with only one recorded sale.
The Berlin group published periodicals such as Club Dada, Der Dada, Everyman His Own Football, and Dada Almanach. They also established a political party, the Central Council of Dada for the World Revolution.
In Cologne, Ernst, Baargeld, and Arp launched a controversial Dada exhibition in 1920 which focused on nonsense and anti-bourgeois sentiments. Cologne's Early Spring Exhibition was set up in a pub, and required that participants walk past urinals while being read lewd poetry by a woman in a communion dress. The police closed the exhibition on grounds of obscenity, but it was re-opened when the charges were dropped.
Like Zürich, New York City was a refuge for writers and artists from the First World War. Soon after arriving from France in 1915, Marcel Duchamp and Francis Picabia met American artist Man Ray. By 1916 the three of them became the center of radical anti-art activities in the United States. American Beatrice Wood, who had been studying in France, soon joined them, along with Elsa von Freytag-Loringhoven. Arthur Cravan, fleeing conscription in France, was also in New York for a time. Much of their activity centered in Alfred Stieglitz's gallery, 291, and the home of Walter and Louise Arensberg.
The New Yorkers, though not particularly organized, called their activities Dada, but they did not issue manifestos. They issued challenges to art and culture through publications such as The Blind Man, Rongwrong, and New York Dada in which they criticized the traditionalist basis for museum art. New York Dada lacked the disillusionment of European Dada and was instead driven by a sense of irony and humor. In his book Adventures in the arts: informal chapters on painters, vaudeville and poets Marsden Hartley included an essay on "The Importance of Being 'Dada' ".
During this time Duchamp began exhibiting "readymades" (everyday objects found or purchased and declared art) such as a bottle rack, and was active in the Society of Independent Artists. In 1917 he submitted the now famous Fountain, a urinal signed R. Mutt, to the Society of Independent Artists exhibition but they rejected the piece. First an object of scorn within the arts community, the Fountain has since become almost canonized by some as one of the most recognizable modernist works of sculpture. Art world experts polled by the sponsors of the 2004 Turner Prize, Gordon's gin, voted it "the most influential work of modern art".
As recent scholarship documents, the work is still controversial. Duchamp indicated in a 1917 letter to his sister that a female friend was centrally involved in the conception of this work: "One of my female friends who had adopted the pseudonym Richard Mutt sent me a porcelain urinal as a sculpture." The piece is in line with the scatological aesthetics of Duchamp's neighbour, the Baroness Elsa von Freytag-Loringhoven. In an attempt to "pay homage to the spirit of Dada" a performance artist named Pierre Pinoncelli made a crack in a replica of The Fountain with a hammer in January 2006; he also urinated on it in 1993.
Picabia's travels tied New York, Zürich and Paris groups together during the Dadaist period. For seven years he also published the Dada periodical 391 in Barcelona, New York City, Zürich, and Paris from 1917 through 1924.
By 1921, most of the original players moved to Paris where Dada had experienced its last major incarnation.
The French avant-garde kept abreast of Dada activities in Zürich with regular communications from Tristan Tzara (whose pseudonym means "sad in country," a name chosen to protest the treatment of Jews in his native Romania), who exchanged letters, poems, and magazines with Guillaume Apollinaire, André Breton, Max Jacob, Clément Pansaers, and other French writers, critics and artists.
Paris had arguably been the classical music capital of the world since the advent of musical Impressionism in the late 19th century. One of its practitioners, Erik Satie, collaborated with Picasso and Cocteau in a mad, scandalous ballet called Parade. First performed by the Ballets Russes in 1917, it succeeded in creating a scandal but in a different way than Stravinsky's Le Sacre du printemps had done almost five years earlier. This was a ballet that was clearly parodying itself, something traditional ballet patrons would obviously have serious issues with.
Dada in Paris surged in 1920 when many of the originators converged there. Inspired by Tzara, Paris Dada soon issued manifestos, organized demonstrations, staged performances and produced a number of journals (the final two editions of Dada, Le Cannibale, and Littérature featured Dada in several editions.)
The first introduction of Dada artwork to the Parisian public was at the Salon des Indépendants in 1921. Jean Crotti exhibited works associated with Dada including a work entitled, Explicatif bearing the word Tabu. In the same year Tzara staged his Dadaist play The Gas Heart to howls of derision from the audience. When it was re-staged in 1923 in a more professional production, the play provoked a theatre riot (initiated by André Breton) that heralded the split within the movement that was to produce Surrealism. Tzara's last attempt at a Dadaist drama was his "ironic tragedy" Handkerchief of Clouds in 1924.
In the Netherlands the Dada movement centered mainly around Theo van Doesburg, best known for establishing the De Stijl movement and magazine of the same name. Van Doesburg mainly focused on poetry, and included poems from many well-known Dada writers in De Stijl such as Hugo Ball, Hans Arp and Kurt Schwitters. Van Doesburg and Thijs Rinsema [nl] (a cordwainer and artist in Drachten) became friends of Schwitters, and together they organized the so-called Dutch Dada campaign in 1923, where van Doesburg promoted a leaflet about Dada (entitled What is Dada?), Schwitters read his poems, Vilmos Huszár demonstrated a mechanical dancing doll and Nelly van Doesburg (Theo's wife), played avant-garde compositions on piano.
Van Doesburg wrote Dada poetry himself in De Stijl, although under a pseudonym, I.K. Bonset, which was only revealed after his death in 1931. 'Together' with I.K. Bonset, he also published a short-lived Dutch Dada magazine called Mécano (1922–23). Another Dutchman identified by K. Schippers in his study of the movement in the Netherlands was the Groningen typographer H. N. Werkman, who was in touch with van Doesburg and Schwitters while editing his own magazine, The Next Call (1923–6). Two more artists mentioned by Schippers were German-born and eventually settled in the Netherlands. These were Otto van Rees, who had taken part in the liminal exhibitions at the Café Voltaire in Zürich, and Paul Citroen.
Though Dada itself was unknown in Georgia until at least 1920, from 1917 until 1921 a group of poets called themselves Le Degré 41", or "Le Degré Quarante et Un" (English, "The 41st Degree") (referring both to the latitude of Tbilisi, Georgia and to the Celsius temperature of a high fever [equal to 105.8 Fahrenheit]) organized along Dadaist lines. The most important figure in this group was Iliazd (Ilia Zdanevich), whose radical typographical designs visually echo the publications of the Dadaists.
After his flight to Paris in 1921, he collaborated with Dadaists on publications and events. For example, when Tristan Tzara was banned from holding seminars in Théâtre Michel in 1923, Iliazd booked the venue on his behalf for the performance, "The Bearded Heart Soirée", and designed the flyer.
In Yugoslavia, alongside the new art movement Zenitism, there was significant Dada activity between 1920 and 1922, run mainly by Dragan Aleksić and including work by Mihailo S. Petrov, Ljubomir Micić and Branko Ve Poljanski. Aleksić used the term "Yougo-Dada" and is known to have been in contact with Raoul Hausmann, Kurt Schwitters, and Tristan Tzara.
The Dada movement in Italy, based in Mantua, was met with distaste and failed to make a significant impact in the world of art. It published a magazine for a short time and held an exhibition in Rome, featuring paintings, quotations from Tristan Tzara, and original epigrams such as "True Dada is against Dada". One member of this group was Julius Evola, who went on to become an eminent scholar of occultism, as well as a right-wing philosopher.
A prominent Dada group in Japan was Mavo, founded in July 1923 by Tomoyoshi Murayama, and Yanase Masamu later joined by Tatsuo Okada. Other prominent artists were Jun Tsuji, Eisuke Yoshiyuki, Shinkichi Takahashi and Katué Kitasono.
In Tsuburaya Productions's Ultra Series, an alien named Dada was inspired by the Dadaism movement, with said character first appearing in episode 28 of the 1966 tokusatsu series, Ultraman, its design by character artist Toru Narita. Dada's design is primarily monochromatic, and features numerous sharp lines and alternating black and white stripes, in reference to the movement and, in particular, to chessboard and Go patterns. On May 19, 2016, in celebration to the 100 year anniversary of Dadaism in Tokyo, the Ultra Monster was invited to meet the Swiss Ambassador Urs Bucher.
Butoh, the Japanese dance-form originating in 1959, can be considered to have direct connections to the spirit of the Dada movement, as Tatsumi Hijikata, one of Butoh's founders, "was influenced early in his career by Dadaism".
Dada in itself was relatively unknown in Russia, however, avant-garde art was widespread due to the Bolsheviks' revolutionary agenda. The Nichevoki [ru], a literary group sharing Dadaist ideals achieved infamy after one of its members suggested that Vladimir Mayakovsky should go to the "Pampushka" (Pameatnik Pushkina – Pushkin monument) on the "Tverbul" (Tverskoy Boulevard) to clean the shoes of anyone who desired it, after Mayakovsky declared that he was going to cleanse Russian literature. For more information on Dadaism's influence upon Russian avant-garde art, see the book Russian Dada 1914–1924.
Often overlooked when discussing the history and foundations of Dada, it is necessary to shed light on the female artists who created and inspired art and artists alike. These women were often times in platonic or romantic relationships with the male Dadaists mentioned above but are rarely written past the relative ties. However, each artist made vital contributions to the movement. Other notable mentions that do not include the artists below are: Suzanne Duchamp, Elsa von Freytag-Loringhoven, Emmy Hennings, Beatrice Wood, Clara Tice, and Ella Bergmann-Michel.
Hannah Höch of Berlin is considered to be the only female Dadaist in Berlin at the time of the movement. During this time, she was in a relationship with Raoul Hausmann who also was a Dada artist. She channeled the same anti-war and anti-government (Weimar Republic) in her works but brought out a feminist lens on the themes. With her works primarily of collage and photomontage, she often used precise placement or detailed titles to callout the misogynistic ways she and other women were treated.
Sophie Taeuber-Arp was a Swiss artist, teacher, and dancer who produced various types of fine art and handicraft pieces. While married to Dadaist Jean Arp, Taeuber-Arp was known in the Dada community for her performative dancing. As such, she worked with choreographer Rudolf von Laban and was written by Tristan Tarza for her dancing skills.
London-born Mina Loy was known for being active in the literary sector of the New York Dada scene. She spent time writing poetry, creating Dada magazines, and acting and writing in plays. She contributed writing to Dada journal The Blind Man and Marchel Duchamp's Rongwrong.
Dadists used shock, nihilism, negativity, paradox, randomness, subconscious forces and antinomianism to subvert established traditions in the aftermath of the Great War. Tzara's 1920 manifesto proposed cutting words from a newspaper and randomly selecting fragments to write poetry, a process in which the synchronous universe itself becomes an active agent in creating the art. A poem written using this technique would be a "fruit" of the words that were clipped from the article.
In literary arts Dadaists focused on poetry, particularly the so-called sound poetry invented by Hugo Ball. Dadaist poems attacked traditional conceptions of poetry, including structure, order, as well as the interplay of sound and the meaning of language. For Dadaists, the existing system by which information is articulated robs language of its dignity. The dismantling of language and poetic conventions are Dadaist attempts to restore language to its purest and most innocent form: "With these sound poem, we wanted to dispense with a language which journalism had made desolate and impossible."
Simultaneous poems (or poèmes simultanés) were recited by a group of speakers who, collectively, produced a chaotic and confusing set of voices. These poems are considered manifestations of modernity including advertising, technology, and conflict. Unlike movements such as Expressionism, Dadaism did not take a negative view of modernity and the urban life. The chaotic urban and futuristic world is considered natural terrain that opens up new ideas for life and art.
Dada was not confined to the visual and literary arts; its influence reached into sound and music. These movements exerted a pervasive influence on 20th-century music, especially on mid-century avant-garde composers based in New York—among them Edgard Varèse, Stefan Wolpe, John Cage, and Morton Feldman. Kurt Schwitters developed what he called sound poems, while Francis Picabia and Georges Ribemont-Dessaignes composed Dada music performed at the Festival Dada in Paris on 26 May 1920. Other composers such as Erwin Schulhoff, Hans Heusser and Alberto Savinio all wrote Dada music, while members of Les Six collaborated with members of the Dada movement and had their works performed at Dada gatherings. Erik Satie also dabbled with Dadaist ideas during his career.
While broadly based, the movement was unstable. By 1924 in Paris, Dada was melding into Surrealism, and artists had gone on to other ideas and movements, including Surrealism, social realism and other forms of modernism. Some theorists argue that Dada was actually the beginning of postmodern art.
By the dawn of the Second World War, many of the European Dadaists had emigrated to the United States. Some (Otto Freundlich, Walter Serner) died in death camps under Adolf Hitler, who actively persecuted the kind of "degenerate art" that he considered Dada to represent. The movement became less active as post-war optimism led to the development of new movements in art and literature.
Dada is a named influence and reference of various anti-art and political and cultural movements, including the Situationist International and culture jamming groups like the Cacophony Society. Upon breaking up in July 2012, anarchist pop band Chumbawamba issued a statement which compared their own legacy with that of the Dada art movement.
At the same time that the Zürich Dadaists were making noise and spectacle at the Cabaret Voltaire, Lenin was planning his revolutionary plans for Russia in a nearby apartment. Tom Stoppard used this coincidence as a premise for his play Travesties (1974), which includes Tzara, Lenin, and James Joyce as characters. French writer Dominique Noguez imagined Lenin as a member of the Dada group in his tongue-in-cheek Lénine Dada (1989).
The former building of the Cabaret Voltaire fell into disrepair until it was occupied from January to March 2002, by a group proclaiming themselves Neo-Dadaists, led by Mark Divo. The group included Jan Thieler, Ingo Giezendanner, Aiana Calugar, Lennie Lee, and Dan Jones. After their eviction, the space was turned into a museum dedicated to the history of Dada. The work of Lee and Jones remained on the walls of the new museum.
Several notable retrospectives have examined the influence of Dada upon art and society. In 1967, a large Dada retrospective was held in Paris. In 2006, the Museum of Modern Art in New York City mounted a Dada exhibition in partnership with the National Gallery of Art in Washington, D.C., and the Centre Pompidou in Paris. The LTM label has released a large number of Dada-related sound recordings, including interviews with artists such as Tzara, Picabia, Schwitters, Arp, and Huelsenbeck, and musical repertoire including Satie, Ribemont-Dessaignes, Picabia, and Nelly van Doesburg.
Musician Frank Zappa was a self-proclaimed Dadaist after learning of the movement:
In the early days, I didn't even know what to call the stuff my life was made of. You can imagine my delight when I discovered that someone in a distant land had the same idea—AND a nice, short name for it.
David Bowie adapted William S. Burrough's cut-up technique for writing lyrics and Kurt Cobain also admittedly used this method for many of his Nirvana lyrics, including "In Bloom".
Dadaism also blurred the line between literary and visual arts:
Dada is the groundwork to abstract art and sound poetry, a starting point for performance art, a prelude to postmodernism, an influence on pop art, a celebration of antiart to be later embraced for anarcho-political uses in the 1960s and the movement that laid the foundation for Surrealism.
The Dadaists imitated the techniques developed during the cubist movement through the pasting of cut pieces of paper items, but extended their art to encompass items such as transportation tickets, maps, plastic wrappers, etc. to portray aspects of life, rather than representing objects viewed as still life. They also invented the “chance collage" technique, involving dropping torn scraps of paper onto a larger sheet and then pasting the pieces wherever they landed.
Cut-up technique is an extension of collage to words themselves, Tristan Tzara describes this in the Dada Manifesto:
TO MAKE A DADAIST POEM Take a newspaper. Take some scissors. Choose from this paper an article of the length you want to make your poem. Cut out the article. Next carefully cut out each of the words that makes up this article and put them all in a bag. Shake gently. Next take out each cutting one after the other. Copy conscientiously in the order in which they left the bag. The poem will resemble you. And there you are – an infinitely original author of charming sensibility, even though unappreciated by the vulgar herd.
The Dadaists – the "monteurs" (mechanics) – used scissors and glue rather than paintbrushes and paints to express their views of modern life through images presented by the media. A variation on the collage technique, photomontage utilized actual or reproductions of real photographs printed in the press. In Cologne, Max Ernst used images from the First World War to illustrate messages of the destruction of war. Although the Berlin photomontages were assembled, like engines, the (non)relationships among the disparate elements were more rhetorical than real.
The assemblages were three-dimensional variations of the collage – the assembly of everyday objects to produce meaningful or meaningless (relative to the war) pieces of work including war objects and trash. Objects were nailed, screwed or fastened together in different fashions. Assemblages could be seen in the round or could be hung on a wall.
Marcel Duchamp began to view the manufactured objects of his collection as objects of art, which he called "readymades". He would add signatures and titles to some, converting them into artwork that he called "readymade aided" or "rectified readymades". Duchamp wrote: "One important characteristic was the short sentence which I occasionally inscribed on the 'readymade.' That sentence, instead of describing the object like a title, was meant to carry the mind of the spectator towards other regions more verbal. Sometimes I would add a graphic detail of presentation which in order to satisfy my craving for alliterations, would be called 'readymade aided.'" One such example of Duchamp's readymade works is the urinal that was turned onto its back, signed "R. Mutt", titled Fountain, and submitted to the Society of Independent Artists exhibition that year, though it was not displayed.
Many young artists in America embraced the theories and ideas espoused by Duchamp. Robert Rauschenberg in particular was very influenced by Dadaism and tended to use found objects in his collages as a means of dissolving the boundary between high and low culture.
Sources
Manifestos | [
{
"paragraph_id": 0,
"text": "Dada (/ˈdɑːdɑː/) or Dadaism was an art movement of the European avant-garde in the early 20th century, with early centres in Zürich, Switzerland, at the Cabaret Voltaire (in 1916), founded by Hugo Ball with his companion Emmy Hennings, and in Berlin in 1917. New York Dada began c. 1915, and after 1920 Dada flourished in Paris. Dadaist activities lasted until the mid 1920s.",
"title": ""
},
{
"paragraph_id": 1,
"text": "Developed in reaction to World War I, the Dada movement consisted of artists who rejected the logic, reason, and aestheticism of modern capitalist society, instead expressing nonsense, irrationality, and anti-bourgeois protest in their works. The art of the movement began primarily as performance art, but eventually spanned visual, literary, and sound media, including collage, sound poetry, cut-up writing, and sculpture. Dadaist artists expressed their discontent toward violence, war, and nationalism and maintained political affinities with radical politics on the left-wing and far-left politics.",
"title": ""
},
{
"paragraph_id": 2,
"text": "There is no consensus on the origin of the movement's name; a common story is that the German artist Richard Huelsenbeck slid a paper knife (letter-opener) at random into a dictionary, where it landed on \"dada\", a colloquial French term for a hobby horse. Jean Arp wrote that Tristan Tzara invented the word at 6 p.m. on 6 February 1916, in the Café de la Terrasse in Zürich. Others note that it suggests the first words of a child, evoking a childishness and absurdity that appealed to the group. Still others speculate that the word might have been chosen to evoke a similar meaning (or no meaning at all) in any language, reflecting the movement's internationalism.",
"title": ""
},
{
"paragraph_id": 3,
"text": "The roots of Dada lie in pre-war avant-garde. The term anti-art, a precursor to Dada, was coined by Marcel Duchamp around 1913 to characterize works that challenge accepted definitions of art. Cubism and the development of collage and abstract art would inform the movement's detachment from the constraints of reality and convention. The work of French poets, Italian Futurists and the German Expressionists would influence Dada's rejection of the tight correlation between words and meaning. Works such as Ubu Roi (1896) by Alfred Jarry and the ballet Parade (1916–17) by Erik Satie would also be characterized as proto-Dadaist works. The Dada movement's principles were first collected in Hugo Ball's Dada Manifesto in 1916. Ball is seen as the founder of the Dada movement.",
"title": ""
},
{
"paragraph_id": 4,
"text": "The Dadaist movement included public gatherings, demonstrations, and publication of art/literary journals; passionate coverage of art, politics, and culture were topics often discussed in a variety of media. Key figures in the movement included Jean Arp, Johannes Baader, Hugo Ball, Marcel Duchamp, Max Ernst, Elsa von Freytag-Loringhoven, George Grosz, Raoul Hausmann, John Heartfield, Emmy Hennings, Hannah Höch, Richard Huelsenbeck, Francis Picabia, Man Ray, Hans Richter, Kurt Schwitters, Sophie Taeuber-Arp, Tristan Tzara, and Beatrice Wood, among others. The movement influenced later styles like the avant-garde and downtown music movements, and groups including Surrealism, nouveau réalisme, pop art and Fluxus.",
"title": ""
},
{
"paragraph_id": 5,
"text": "Dada was an informal international movement, with participants in Europe and North America. The beginnings of Dada correspond with the outbreak of World War I. For many participants, the movement was a protest against the bourgeois nationalist and colonialist interests, which many Dadaists believed were the root cause of the war, and against the cultural and intellectual conformity—in art and more broadly in society—that corresponded to the war.",
"title": "Overview"
},
{
"paragraph_id": 6,
"text": "Avant-garde circles outside France knew of pre-war Parisian developments. They had seen (or participated in) Cubist exhibitions held at Galeries Dalmau, Barcelona (1912), Galerie Der Sturm in Berlin (1912), the Armory Show in New York (1913), SVU Mánes in Prague (1914), several Jack of Diamonds exhibitions in Moscow and at Moderne Kunstkring, Amsterdam (between 1911 and 1915). Futurism developed in response to the work of various artists. Dada subsequently combined these approaches.",
"title": "Overview"
},
{
"paragraph_id": 7,
"text": "Many Dadaists believed that the 'reason' and 'logic' of bourgeois capitalist society had led people into war. They expressed their rejection of that ideology in artistic expression that appeared to reject logic and embrace chaos and irrationality. For example, George Grosz later recalled that his Dadaist art was intended as a protest \"against this world of mutual destruction\".",
"title": "Overview"
},
{
"paragraph_id": 8,
"text": "According to Hans Richter Dada was not art: it was \"anti-art\". Dada represented the opposite of everything which art stood for. Where art was concerned with traditional aesthetics, Dada ignored aesthetics. If art was to appeal to sensibilities, Dada was intended to offend.",
"title": "Overview"
},
{
"paragraph_id": 9,
"text": "Additionally, Dada attempted to reflect onto human perception and the chaotic nature of society. Tristan Tzara proclaimed, \"Everything is Dada, too. Beware of Dada. Anti-dadaism is a disease: selfkleptomania, man's normal condition, is Dada. But the real Dadas are against Dada\".",
"title": "Overview"
},
{
"paragraph_id": 10,
"text": "As Hugo Ball expressed it, \"For us, art is not an end in itself ... but it is an opportunity for the true perception and criticism of the times we live in.\"",
"title": "Overview"
},
{
"paragraph_id": 11,
"text": "A reviewer from the American Art News stated at the time that \"Dada philosophy is the sickest, most paralyzing and most destructive thing that has ever originated from the brain of man.\" Art historians have described Dada as being, in large part, a \"reaction to what many of these artists saw as nothing more than an insane spectacle of collective homicide\".",
"title": "Overview"
},
{
"paragraph_id": 12,
"text": "Years later, Dada artists described the movement as \"a phenomenon bursting forth in the midst of the postwar economic and moral crisis, a savior, a monster, which would lay waste to everything in its path... [It was] a systematic work of destruction and demoralization... In the end it became nothing but an act of sacrilege.\"",
"title": "Overview"
},
{
"paragraph_id": 13,
"text": "To quote Dona Budd's The Language of Art Knowledge,",
"title": "Overview"
},
{
"paragraph_id": 14,
"text": "Dada was born out of negative reaction to the horrors of the First World War. This international movement was begun by a group of artists and poets associated with the Cabaret Voltaire in Zürich. Dada rejected reason and logic, prizing nonsense, irrationality and intuition. The origin of the name Dada is unclear; some believe that it is a nonsensical word. Others maintain that it originates from the Romanian artists Tristan Tzara's and Marcel Janco's frequent use of the words \"da, da,\" meaning \"yes, yes\" in the Romanian language. Another theory says that the name \"Dada\" came during a meeting of the group when a paper knife stuck into a French–German dictionary happened to point to 'dada', a French word for 'hobbyhorse'.",
"title": "Overview"
},
{
"paragraph_id": 15,
"text": "The movement primarily involved visual arts, literature, poetry, art manifestos, art theory, theatre, and graphic design, and concentrated its anti-war politics through a rejection of the prevailing standards in art through anti-art cultural works.",
"title": "Overview"
},
{
"paragraph_id": 16,
"text": "The creations of Duchamp, Picabia, Man Ray, and others between 1915 and 1917 eluded the term Dada at the time, and \"New York Dada\" came to be seen as a post facto invention of Duchamp. At the outset of the 1920s the term Dada flourished in Europe with the help of Duchamp and Picabia, who had both returned from New York. Notwithstanding, Dadaists such as Tzara and Richter claimed European precedence. Art historian David Hopkins notes:",
"title": "Overview"
},
{
"paragraph_id": 17,
"text": "Ironically, though, Duchamp's late activities in New York, along with the machinations of Picabia, re-cast Dada's history. Dada's European chroniclers—primarily Richter, Tzara, and Huelsenbeck—would eventually become preoccupied with establishing the pre-eminence of Zurich and Berlin at the foundations of Dada, but it proved to be Duchamp who was most strategically brilliant in manipulating the genealogy of this avant-garde formation, deftly turning New York Dada from a late-comer into an originating force.",
"title": "Overview"
},
{
"paragraph_id": 18,
"text": "Dada emerged from a period of artistic and literary movements like Futurism, Cubism and Expressionism; centered mainly in Italy, France and Germany respectively, in those years. However, unlike the earlier movements Dada was able to establish a broad base of support, giving rise to a movement that was international in scope. Its adherents were based in cities all over the world including New York, Zürich, Berlin, Paris and others. There were regional differences like an emphasis on literature in Zürich and political protest in Berlin.",
"title": "History"
},
{
"paragraph_id": 19,
"text": "Prominent Dadaists published manifestos, but the movement was loosely organized and there was no central hierarchy. On 14 July 1916, Ball originated the seminal Dada Manifesto. Tzara wrote a second Dada manifesto, considered important Dada reading, which was published in 1918. Tzara's manifesto articulated the concept of \"Dadaist disgust\"—the contradiction implicit in avant-garde works between the criticism and affirmation of modernist reality. In the Dadaist perspective modern art and culture are considered a type of fetishization where the objects of consumption (including organized systems of thought like philosophy and morality) are chosen, much like a preference for cake or cherries, to fill a void.",
"title": "History"
},
{
"paragraph_id": 20,
"text": "The shock and scandal the movement inflamed was deliberate; Dadaist magazines were banned and their exhibits closed. Some of the artists even faced imprisonment. These provocations were part of the entertainment but, over time, audiences' expectations eventually outpaced the movement's capacity to deliver. As the artists' well-known \"sarcastic laugh\" started to come from the audience, the provocations of Dadaists began to lose their impact. Dada was an active movement during years of political turmoil from 1916 when European countries were actively engaged in World War I, the conclusion of which, in 1918, set the stage for a new political order.",
"title": "History"
},
{
"paragraph_id": 21,
"text": "There is some disagreement about where Dada originated. The movement is commonly accepted by most art historians and those who lived during this period to have identified with the Cabaret Voltaire (housed inside the Holländische Meierei bar in Zürich) co-founded by poet and cabaret singer Emmy Hennings and Hugo Ball. Some sources propose a Romanian origin, arguing that Dada was an offshoot of a vibrant artistic tradition that transposed to Switzerland when a group of Jewish modernist artists, including Tristan Tzara, Marcel Janco, and Arthur Segal settled in Zürich. Before World War I, similar art had already existed in Bucharest and other Eastern European cities; it is likely that Dada's catalyst was the arrival in Zürich of artists like Tzara and Janco.",
"title": "History"
},
{
"paragraph_id": 22,
"text": "The name Cabaret Voltaire was a reference to the French philosopher Voltaire, whose novel Candide mocked the religious and philosophical dogmas of the day. Opening night was attended by Ball, Tzara, Jean Arp, and Janco. These artists along with others like Sophie Taeuber, Richard Huelsenbeck and Hans Richter started putting on performances at the Cabaret Voltaire and using art to express their disgust with the war and the interests that inspired it.",
"title": "History"
},
{
"paragraph_id": 23,
"text": "Having left Germany and Romania during World War I, the artists arrived in politically neutral Switzerland. They used abstraction to fight against the social, political, and cultural ideas of that time. They used shock art, provocation, and \"vaudevilleian excess\" to subvert the conventions they believed had caused the Great War. The Dadaists believed those ideas to be a byproduct of bourgeois society that was so apathetic it would wage war against itself rather than challenge the status quo:",
"title": "History"
},
{
"paragraph_id": 24,
"text": "We had lost confidence in our culture. Everything had to be demolished. We would begin again after the tabula rasa. At the Cabaret Voltaire we began by shocking common sense, public opinion, education, institutions, museums, good taste, in short, the whole prevailing order.",
"title": "History"
},
{
"paragraph_id": 25,
"text": "Ball said that Janco's mask and costume designs, inspired by Romanian folk art, made \"the horror of our time, the paralyzing background of events\" visible. According to Ball, performances were accompanied by a \"balalaika orchestra playing delightful folk-songs\". Influenced by African music, arrhythmic drumming and jazz were common at Dada gatherings.",
"title": "History"
},
{
"paragraph_id": 26,
"text": "After the cabaret closed down, Dada activities moved on to a new gallery, and Hugo Ball left for Bern. Tzara began a relentless campaign to spread Dada ideas. He bombarded French and Italian artists and writers with letters, and soon emerged as the Dada leader and master strategist. The Cabaret Voltaire re-opened, and is still in the same place at the Spiegelgasse 1 in the Niederdorf.",
"title": "History"
},
{
"paragraph_id": 27,
"text": "Zürich Dada, with Tzara at the helm, published the art and literature review Dada beginning in July 1917, with five editions from Zürich and the final two from Paris.",
"title": "History"
},
{
"paragraph_id": 28,
"text": "Other artists, such as André Breton and Philippe Soupault, created \"literature groups to help extend the influence of Dada\".",
"title": "History"
},
{
"paragraph_id": 29,
"text": "After the fighting of the First World War had ended in the armistice of November 1918, most of the Zürich Dadaists returned to their home countries, and some began Dada activities in other cities. Others, such as the Swiss native Sophie Taeuber, would remain in Zürich into the 1920s.",
"title": "History"
},
{
"paragraph_id": 30,
"text": "\"Berlin was a city of tightened stomachers, of mounting, thundering hunger, where hidden rage was transformed into a boundless money lust, and men's minds were concentrating more and more on questions of naked existence... Fear was in everybody's bones\" – Richard Hülsenbeck",
"title": "History"
},
{
"paragraph_id": 31,
"text": "Raoul Hausmann, who helped establish Dada in Berlin, published his manifesto Synthethic Cino of Painting in 1918 where he attacked Expressionism and the art critics who promoted it. Dada is envisioned in contrast to art forms, such as Expressionism, that appeal to viewers' emotional states: \"the exploitation of so-called echoes of the soul\". In Hausmann's conception of Dada, new techniques of creating art would open doors to explore new artistic impulses. Fragmented use of real world stimuli allowed an expression of reality that was radically different from other forms of art:",
"title": "History"
},
{
"paragraph_id": 32,
"text": "A child's discarded doll or a brightly colored rag are more necessary expressions than those of some ass who seeks to immortalize himself in oils in finite parlors.",
"title": "History"
},
{
"paragraph_id": 33,
"text": "The groups in Germany were not as strongly anti-art as other groups. Their activity and art were more political and social, with corrosive manifestos and propaganda, satire, public demonstrations and overt political activities. The intensely political and war-torn environment of Berlin had a dramatic impact on the ideas of Berlin Dadaists. Conversely, New York's geographic distance from the war spawned its more theoretically-driven, less political nature. According to Hans Richter, a Dadaist who was in Berlin yet “aloof from active participation in Berlin Dada”, several distinguishing characteristics of the Dada movement there included: “its political element and its technical discoveries in painting and literature”; “inexhaustible energy”; “mental freedom which included the abolition of everything”; and “members intoxicated with their own power in a way that had no relation to the real world”, who would “turn their rebelliousness even against each other”.",
"title": "History"
},
{
"paragraph_id": 34,
"text": "In February 1918, while the Great War was approaching its climax, Huelsenbeck gave his first Dada speech in Berlin, and he produced a Dada manifesto later in the year. Following the October Revolution in Russia, by then out of the war, Hannah Höch and George Grosz used Dada to express communist sympathies. Grosz, together with John Heartfield, Höch and Hausmann developed the technique of photomontage during this period. Johannes Baader, the uninhibited Oberdada, was the “crowbar” of the Berlin movement's direct action according to Hans Richter and is credited with creating the first giant collages, according to Raoul Hausmann.",
"title": "History"
},
{
"paragraph_id": 35,
"text": "After the war, the artists published a series of short-lived political magazines and held the First International Dada Fair, 'the greatest project yet conceived by the Berlin Dadaists', in the summer of 1920. As well as work by the main members of Berlin Dada – Grosz, Raoul Hausmann, Hannah Höch, Johannes Baader, Huelsenbeck and Heartfield – the exhibition also included the work of Otto Dix, Francis Picabia, Jean Arp, Max Ernst, Rudolf Schlichter, Johannes Baargeld and others. In all, over 200 works were exhibited, surrounded by incendiary slogans, some of which also ended up written on the walls of the Nazi's Entartete Kunst exhibition in 1937. Despite high ticket prices, the exhibition lost money, with only one recorded sale.",
"title": "History"
},
{
"paragraph_id": 36,
"text": "The Berlin group published periodicals such as Club Dada, Der Dada, Everyman His Own Football, and Dada Almanach. They also established a political party, the Central Council of Dada for the World Revolution.",
"title": "History"
},
{
"paragraph_id": 37,
"text": "In Cologne, Ernst, Baargeld, and Arp launched a controversial Dada exhibition in 1920 which focused on nonsense and anti-bourgeois sentiments. Cologne's Early Spring Exhibition was set up in a pub, and required that participants walk past urinals while being read lewd poetry by a woman in a communion dress. The police closed the exhibition on grounds of obscenity, but it was re-opened when the charges were dropped.",
"title": "History"
},
{
"paragraph_id": 38,
"text": "Like Zürich, New York City was a refuge for writers and artists from the First World War. Soon after arriving from France in 1915, Marcel Duchamp and Francis Picabia met American artist Man Ray. By 1916 the three of them became the center of radical anti-art activities in the United States. American Beatrice Wood, who had been studying in France, soon joined them, along with Elsa von Freytag-Loringhoven. Arthur Cravan, fleeing conscription in France, was also in New York for a time. Much of their activity centered in Alfred Stieglitz's gallery, 291, and the home of Walter and Louise Arensberg.",
"title": "History"
},
{
"paragraph_id": 39,
"text": "The New Yorkers, though not particularly organized, called their activities Dada, but they did not issue manifestos. They issued challenges to art and culture through publications such as The Blind Man, Rongwrong, and New York Dada in which they criticized the traditionalist basis for museum art. New York Dada lacked the disillusionment of European Dada and was instead driven by a sense of irony and humor. In his book Adventures in the arts: informal chapters on painters, vaudeville and poets Marsden Hartley included an essay on \"The Importance of Being 'Dada' \".",
"title": "History"
},
{
"paragraph_id": 40,
"text": "During this time Duchamp began exhibiting \"readymades\" (everyday objects found or purchased and declared art) such as a bottle rack, and was active in the Society of Independent Artists. In 1917 he submitted the now famous Fountain, a urinal signed R. Mutt, to the Society of Independent Artists exhibition but they rejected the piece. First an object of scorn within the arts community, the Fountain has since become almost canonized by some as one of the most recognizable modernist works of sculpture. Art world experts polled by the sponsors of the 2004 Turner Prize, Gordon's gin, voted it \"the most influential work of modern art\".",
"title": "History"
},
{
"paragraph_id": 41,
"text": "As recent scholarship documents, the work is still controversial. Duchamp indicated in a 1917 letter to his sister that a female friend was centrally involved in the conception of this work: \"One of my female friends who had adopted the pseudonym Richard Mutt sent me a porcelain urinal as a sculpture.\" The piece is in line with the scatological aesthetics of Duchamp's neighbour, the Baroness Elsa von Freytag-Loringhoven. In an attempt to \"pay homage to the spirit of Dada\" a performance artist named Pierre Pinoncelli made a crack in a replica of The Fountain with a hammer in January 2006; he also urinated on it in 1993.",
"title": "History"
},
{
"paragraph_id": 42,
"text": "Picabia's travels tied New York, Zürich and Paris groups together during the Dadaist period. For seven years he also published the Dada periodical 391 in Barcelona, New York City, Zürich, and Paris from 1917 through 1924.",
"title": "History"
},
{
"paragraph_id": 43,
"text": "By 1921, most of the original players moved to Paris where Dada had experienced its last major incarnation.",
"title": "History"
},
{
"paragraph_id": 44,
"text": "The French avant-garde kept abreast of Dada activities in Zürich with regular communications from Tristan Tzara (whose pseudonym means \"sad in country,\" a name chosen to protest the treatment of Jews in his native Romania), who exchanged letters, poems, and magazines with Guillaume Apollinaire, André Breton, Max Jacob, Clément Pansaers, and other French writers, critics and artists.",
"title": "History"
},
{
"paragraph_id": 45,
"text": "Paris had arguably been the classical music capital of the world since the advent of musical Impressionism in the late 19th century. One of its practitioners, Erik Satie, collaborated with Picasso and Cocteau in a mad, scandalous ballet called Parade. First performed by the Ballets Russes in 1917, it succeeded in creating a scandal but in a different way than Stravinsky's Le Sacre du printemps had done almost five years earlier. This was a ballet that was clearly parodying itself, something traditional ballet patrons would obviously have serious issues with.",
"title": "History"
},
{
"paragraph_id": 46,
"text": "Dada in Paris surged in 1920 when many of the originators converged there. Inspired by Tzara, Paris Dada soon issued manifestos, organized demonstrations, staged performances and produced a number of journals (the final two editions of Dada, Le Cannibale, and Littérature featured Dada in several editions.)",
"title": "History"
},
{
"paragraph_id": 47,
"text": "The first introduction of Dada artwork to the Parisian public was at the Salon des Indépendants in 1921. Jean Crotti exhibited works associated with Dada including a work entitled, Explicatif bearing the word Tabu. In the same year Tzara staged his Dadaist play The Gas Heart to howls of derision from the audience. When it was re-staged in 1923 in a more professional production, the play provoked a theatre riot (initiated by André Breton) that heralded the split within the movement that was to produce Surrealism. Tzara's last attempt at a Dadaist drama was his \"ironic tragedy\" Handkerchief of Clouds in 1924.",
"title": "History"
},
{
"paragraph_id": 48,
"text": "In the Netherlands the Dada movement centered mainly around Theo van Doesburg, best known for establishing the De Stijl movement and magazine of the same name. Van Doesburg mainly focused on poetry, and included poems from many well-known Dada writers in De Stijl such as Hugo Ball, Hans Arp and Kurt Schwitters. Van Doesburg and Thijs Rinsema [nl] (a cordwainer and artist in Drachten) became friends of Schwitters, and together they organized the so-called Dutch Dada campaign in 1923, where van Doesburg promoted a leaflet about Dada (entitled What is Dada?), Schwitters read his poems, Vilmos Huszár demonstrated a mechanical dancing doll and Nelly van Doesburg (Theo's wife), played avant-garde compositions on piano.",
"title": "History"
},
{
"paragraph_id": 49,
"text": "Van Doesburg wrote Dada poetry himself in De Stijl, although under a pseudonym, I.K. Bonset, which was only revealed after his death in 1931. 'Together' with I.K. Bonset, he also published a short-lived Dutch Dada magazine called Mécano (1922–23). Another Dutchman identified by K. Schippers in his study of the movement in the Netherlands was the Groningen typographer H. N. Werkman, who was in touch with van Doesburg and Schwitters while editing his own magazine, The Next Call (1923–6). Two more artists mentioned by Schippers were German-born and eventually settled in the Netherlands. These were Otto van Rees, who had taken part in the liminal exhibitions at the Café Voltaire in Zürich, and Paul Citroen.",
"title": "History"
},
{
"paragraph_id": 50,
"text": "Though Dada itself was unknown in Georgia until at least 1920, from 1917 until 1921 a group of poets called themselves Le Degré 41\", or \"Le Degré Quarante et Un\" (English, \"The 41st Degree\") (referring both to the latitude of Tbilisi, Georgia and to the Celsius temperature of a high fever [equal to 105.8 Fahrenheit]) organized along Dadaist lines. The most important figure in this group was Iliazd (Ilia Zdanevich), whose radical typographical designs visually echo the publications of the Dadaists.",
"title": "History"
},
{
"paragraph_id": 51,
"text": "After his flight to Paris in 1921, he collaborated with Dadaists on publications and events. For example, when Tristan Tzara was banned from holding seminars in Théâtre Michel in 1923, Iliazd booked the venue on his behalf for the performance, \"The Bearded Heart Soirée\", and designed the flyer.",
"title": "History"
},
{
"paragraph_id": 52,
"text": "In Yugoslavia, alongside the new art movement Zenitism, there was significant Dada activity between 1920 and 1922, run mainly by Dragan Aleksić and including work by Mihailo S. Petrov, Ljubomir Micić and Branko Ve Poljanski. Aleksić used the term \"Yougo-Dada\" and is known to have been in contact with Raoul Hausmann, Kurt Schwitters, and Tristan Tzara.",
"title": "History"
},
{
"paragraph_id": 53,
"text": "The Dada movement in Italy, based in Mantua, was met with distaste and failed to make a significant impact in the world of art. It published a magazine for a short time and held an exhibition in Rome, featuring paintings, quotations from Tristan Tzara, and original epigrams such as \"True Dada is against Dada\". One member of this group was Julius Evola, who went on to become an eminent scholar of occultism, as well as a right-wing philosopher.",
"title": "History"
},
{
"paragraph_id": 54,
"text": "A prominent Dada group in Japan was Mavo, founded in July 1923 by Tomoyoshi Murayama, and Yanase Masamu later joined by Tatsuo Okada. Other prominent artists were Jun Tsuji, Eisuke Yoshiyuki, Shinkichi Takahashi and Katué Kitasono.",
"title": "History"
},
{
"paragraph_id": 55,
"text": "In Tsuburaya Productions's Ultra Series, an alien named Dada was inspired by the Dadaism movement, with said character first appearing in episode 28 of the 1966 tokusatsu series, Ultraman, its design by character artist Toru Narita. Dada's design is primarily monochromatic, and features numerous sharp lines and alternating black and white stripes, in reference to the movement and, in particular, to chessboard and Go patterns. On May 19, 2016, in celebration to the 100 year anniversary of Dadaism in Tokyo, the Ultra Monster was invited to meet the Swiss Ambassador Urs Bucher.",
"title": "History"
},
{
"paragraph_id": 56,
"text": "Butoh, the Japanese dance-form originating in 1959, can be considered to have direct connections to the spirit of the Dada movement, as Tatsumi Hijikata, one of Butoh's founders, \"was influenced early in his career by Dadaism\".",
"title": "History"
},
{
"paragraph_id": 57,
"text": "Dada in itself was relatively unknown in Russia, however, avant-garde art was widespread due to the Bolsheviks' revolutionary agenda. The Nichevoki [ru], a literary group sharing Dadaist ideals achieved infamy after one of its members suggested that Vladimir Mayakovsky should go to the \"Pampushka\" (Pameatnik Pushkina – Pushkin monument) on the \"Tverbul\" (Tverskoy Boulevard) to clean the shoes of anyone who desired it, after Mayakovsky declared that he was going to cleanse Russian literature. For more information on Dadaism's influence upon Russian avant-garde art, see the book Russian Dada 1914–1924.",
"title": "History"
},
{
"paragraph_id": 58,
"text": "Often overlooked when discussing the history and foundations of Dada, it is necessary to shed light on the female artists who created and inspired art and artists alike. These women were often times in platonic or romantic relationships with the male Dadaists mentioned above but are rarely written past the relative ties. However, each artist made vital contributions to the movement. Other notable mentions that do not include the artists below are: Suzanne Duchamp, Elsa von Freytag-Loringhoven, Emmy Hennings, Beatrice Wood, Clara Tice, and Ella Bergmann-Michel.",
"title": "Women of Dada"
},
{
"paragraph_id": 59,
"text": "Hannah Höch of Berlin is considered to be the only female Dadaist in Berlin at the time of the movement. During this time, she was in a relationship with Raoul Hausmann who also was a Dada artist. She channeled the same anti-war and anti-government (Weimar Republic) in her works but brought out a feminist lens on the themes. With her works primarily of collage and photomontage, she often used precise placement or detailed titles to callout the misogynistic ways she and other women were treated.",
"title": "Women of Dada"
},
{
"paragraph_id": 60,
"text": "Sophie Taeuber-Arp was a Swiss artist, teacher, and dancer who produced various types of fine art and handicraft pieces. While married to Dadaist Jean Arp, Taeuber-Arp was known in the Dada community for her performative dancing. As such, she worked with choreographer Rudolf von Laban and was written by Tristan Tarza for her dancing skills.",
"title": "Women of Dada"
},
{
"paragraph_id": 61,
"text": "London-born Mina Loy was known for being active in the literary sector of the New York Dada scene. She spent time writing poetry, creating Dada magazines, and acting and writing in plays. She contributed writing to Dada journal The Blind Man and Marchel Duchamp's Rongwrong.",
"title": "Women of Dada"
},
{
"paragraph_id": 62,
"text": "Dadists used shock, nihilism, negativity, paradox, randomness, subconscious forces and antinomianism to subvert established traditions in the aftermath of the Great War. Tzara's 1920 manifesto proposed cutting words from a newspaper and randomly selecting fragments to write poetry, a process in which the synchronous universe itself becomes an active agent in creating the art. A poem written using this technique would be a \"fruit\" of the words that were clipped from the article.",
"title": "Poetry"
},
{
"paragraph_id": 63,
"text": "In literary arts Dadaists focused on poetry, particularly the so-called sound poetry invented by Hugo Ball. Dadaist poems attacked traditional conceptions of poetry, including structure, order, as well as the interplay of sound and the meaning of language. For Dadaists, the existing system by which information is articulated robs language of its dignity. The dismantling of language and poetic conventions are Dadaist attempts to restore language to its purest and most innocent form: \"With these sound poem, we wanted to dispense with a language which journalism had made desolate and impossible.\"",
"title": "Poetry"
},
{
"paragraph_id": 64,
"text": "Simultaneous poems (or poèmes simultanés) were recited by a group of speakers who, collectively, produced a chaotic and confusing set of voices. These poems are considered manifestations of modernity including advertising, technology, and conflict. Unlike movements such as Expressionism, Dadaism did not take a negative view of modernity and the urban life. The chaotic urban and futuristic world is considered natural terrain that opens up new ideas for life and art.",
"title": "Poetry"
},
{
"paragraph_id": 65,
"text": "Dada was not confined to the visual and literary arts; its influence reached into sound and music. These movements exerted a pervasive influence on 20th-century music, especially on mid-century avant-garde composers based in New York—among them Edgard Varèse, Stefan Wolpe, John Cage, and Morton Feldman. Kurt Schwitters developed what he called sound poems, while Francis Picabia and Georges Ribemont-Dessaignes composed Dada music performed at the Festival Dada in Paris on 26 May 1920. Other composers such as Erwin Schulhoff, Hans Heusser and Alberto Savinio all wrote Dada music, while members of Les Six collaborated with members of the Dada movement and had their works performed at Dada gatherings. Erik Satie also dabbled with Dadaist ideas during his career.",
"title": "Music"
},
{
"paragraph_id": 66,
"text": "While broadly based, the movement was unstable. By 1924 in Paris, Dada was melding into Surrealism, and artists had gone on to other ideas and movements, including Surrealism, social realism and other forms of modernism. Some theorists argue that Dada was actually the beginning of postmodern art.",
"title": "Legacy"
},
{
"paragraph_id": 67,
"text": "By the dawn of the Second World War, many of the European Dadaists had emigrated to the United States. Some (Otto Freundlich, Walter Serner) died in death camps under Adolf Hitler, who actively persecuted the kind of \"degenerate art\" that he considered Dada to represent. The movement became less active as post-war optimism led to the development of new movements in art and literature.",
"title": "Legacy"
},
{
"paragraph_id": 68,
"text": "Dada is a named influence and reference of various anti-art and political and cultural movements, including the Situationist International and culture jamming groups like the Cacophony Society. Upon breaking up in July 2012, anarchist pop band Chumbawamba issued a statement which compared their own legacy with that of the Dada art movement.",
"title": "Legacy"
},
{
"paragraph_id": 69,
"text": "At the same time that the Zürich Dadaists were making noise and spectacle at the Cabaret Voltaire, Lenin was planning his revolutionary plans for Russia in a nearby apartment. Tom Stoppard used this coincidence as a premise for his play Travesties (1974), which includes Tzara, Lenin, and James Joyce as characters. French writer Dominique Noguez imagined Lenin as a member of the Dada group in his tongue-in-cheek Lénine Dada (1989).",
"title": "Legacy"
},
{
"paragraph_id": 70,
"text": "The former building of the Cabaret Voltaire fell into disrepair until it was occupied from January to March 2002, by a group proclaiming themselves Neo-Dadaists, led by Mark Divo. The group included Jan Thieler, Ingo Giezendanner, Aiana Calugar, Lennie Lee, and Dan Jones. After their eviction, the space was turned into a museum dedicated to the history of Dada. The work of Lee and Jones remained on the walls of the new museum.",
"title": "Legacy"
},
{
"paragraph_id": 71,
"text": "Several notable retrospectives have examined the influence of Dada upon art and society. In 1967, a large Dada retrospective was held in Paris. In 2006, the Museum of Modern Art in New York City mounted a Dada exhibition in partnership with the National Gallery of Art in Washington, D.C., and the Centre Pompidou in Paris. The LTM label has released a large number of Dada-related sound recordings, including interviews with artists such as Tzara, Picabia, Schwitters, Arp, and Huelsenbeck, and musical repertoire including Satie, Ribemont-Dessaignes, Picabia, and Nelly van Doesburg.",
"title": "Legacy"
},
{
"paragraph_id": 72,
"text": "Musician Frank Zappa was a self-proclaimed Dadaist after learning of the movement:",
"title": "Legacy"
},
{
"paragraph_id": 73,
"text": "In the early days, I didn't even know what to call the stuff my life was made of. You can imagine my delight when I discovered that someone in a distant land had the same idea—AND a nice, short name for it.",
"title": "Legacy"
},
{
"paragraph_id": 74,
"text": "David Bowie adapted William S. Burrough's cut-up technique for writing lyrics and Kurt Cobain also admittedly used this method for many of his Nirvana lyrics, including \"In Bloom\".",
"title": "Legacy"
},
{
"paragraph_id": 75,
"text": "Dadaism also blurred the line between literary and visual arts:",
"title": "Art techniques developed"
},
{
"paragraph_id": 76,
"text": "Dada is the groundwork to abstract art and sound poetry, a starting point for performance art, a prelude to postmodernism, an influence on pop art, a celebration of antiart to be later embraced for anarcho-political uses in the 1960s and the movement that laid the foundation for Surrealism.",
"title": "Art techniques developed"
},
{
"paragraph_id": 77,
"text": "The Dadaists imitated the techniques developed during the cubist movement through the pasting of cut pieces of paper items, but extended their art to encompass items such as transportation tickets, maps, plastic wrappers, etc. to portray aspects of life, rather than representing objects viewed as still life. They also invented the “chance collage\" technique, involving dropping torn scraps of paper onto a larger sheet and then pasting the pieces wherever they landed.",
"title": "Art techniques developed"
},
{
"paragraph_id": 78,
"text": "Cut-up technique is an extension of collage to words themselves, Tristan Tzara describes this in the Dada Manifesto:",
"title": "Art techniques developed"
},
{
"paragraph_id": 79,
"text": "TO MAKE A DADAIST POEM Take a newspaper. Take some scissors. Choose from this paper an article of the length you want to make your poem. Cut out the article. Next carefully cut out each of the words that makes up this article and put them all in a bag. Shake gently. Next take out each cutting one after the other. Copy conscientiously in the order in which they left the bag. The poem will resemble you. And there you are – an infinitely original author of charming sensibility, even though unappreciated by the vulgar herd.",
"title": "Art techniques developed"
},
{
"paragraph_id": 80,
"text": "The Dadaists – the \"monteurs\" (mechanics) – used scissors and glue rather than paintbrushes and paints to express their views of modern life through images presented by the media. A variation on the collage technique, photomontage utilized actual or reproductions of real photographs printed in the press. In Cologne, Max Ernst used images from the First World War to illustrate messages of the destruction of war. Although the Berlin photomontages were assembled, like engines, the (non)relationships among the disparate elements were more rhetorical than real.",
"title": "Art techniques developed"
},
{
"paragraph_id": 81,
"text": "The assemblages were three-dimensional variations of the collage – the assembly of everyday objects to produce meaningful or meaningless (relative to the war) pieces of work including war objects and trash. Objects were nailed, screwed or fastened together in different fashions. Assemblages could be seen in the round or could be hung on a wall.",
"title": "Art techniques developed"
},
{
"paragraph_id": 82,
"text": "Marcel Duchamp began to view the manufactured objects of his collection as objects of art, which he called \"readymades\". He would add signatures and titles to some, converting them into artwork that he called \"readymade aided\" or \"rectified readymades\". Duchamp wrote: \"One important characteristic was the short sentence which I occasionally inscribed on the 'readymade.' That sentence, instead of describing the object like a title, was meant to carry the mind of the spectator towards other regions more verbal. Sometimes I would add a graphic detail of presentation which in order to satisfy my craving for alliterations, would be called 'readymade aided.'\" One such example of Duchamp's readymade works is the urinal that was turned onto its back, signed \"R. Mutt\", titled Fountain, and submitted to the Society of Independent Artists exhibition that year, though it was not displayed.",
"title": "Art techniques developed"
},
{
"paragraph_id": 83,
"text": "Many young artists in America embraced the theories and ideas espoused by Duchamp. Robert Rauschenberg in particular was very influenced by Dadaism and tended to use found objects in his collages as a means of dissolving the boundary between high and low culture.",
"title": "Art techniques developed"
},
{
"paragraph_id": 84,
"text": "Sources",
"title": "References"
},
{
"paragraph_id": 85,
"text": "Manifestos",
"title": "External links"
}
] | Dada or Dadaism was an art movement of the European avant-garde in the early 20th century, with early centres in Zürich, Switzerland, at the Cabaret Voltaire, founded by Hugo Ball with his companion Emmy Hennings, and in Berlin in 1917. New York Dada began c. 1915, and after 1920 Dada flourished in Paris. Dadaist activities lasted until the mid 1920s. Developed in reaction to World War I, the Dada movement consisted of artists who rejected the logic, reason, and aestheticism of modern capitalist society, instead expressing nonsense, irrationality, and anti-bourgeois protest in their works. The art of the movement began primarily as performance art, but eventually spanned visual, literary, and sound media, including collage, sound poetry, cut-up writing, and sculpture. Dadaist artists expressed their discontent toward violence, war, and nationalism and maintained political affinities with radical politics on the left-wing and far-left politics. There is no consensus on the origin of the movement's name; a common story is that the German artist Richard Huelsenbeck slid a paper knife (letter-opener) at random into a dictionary, where it landed on "dada", a colloquial French term for a hobby horse. Jean Arp wrote that Tristan Tzara invented the word at 6 p.m. on 6 February 1916, in the Café de la Terrasse in Zürich. Others note that it suggests the first words of a child, evoking a childishness and absurdity that appealed to the group. Still others speculate that the word might have been chosen to evoke a similar meaning in any language, reflecting the movement's internationalism. The roots of Dada lie in pre-war avant-garde. The term anti-art, a precursor to Dada, was coined by Marcel Duchamp around 1913 to characterize works that challenge accepted definitions of art. Cubism and the development of collage and abstract art would inform the movement's detachment from the constraints of reality and convention. The work of French poets, Italian Futurists and the German Expressionists would influence Dada's rejection of the tight correlation between words and meaning. Works such as Ubu Roi (1896) by Alfred Jarry and the ballet Parade (1916–17) by Erik Satie would also be characterized as proto-Dadaist works. The Dada movement's principles were first collected in Hugo Ball's Dada Manifesto in 1916. Ball is seen as the founder of the Dada movement. The Dadaist movement included public gatherings, demonstrations, and publication of art/literary journals; passionate coverage of art, politics, and culture were topics often discussed in a variety of media. Key figures in the movement included Jean Arp, Johannes Baader, Hugo Ball, Marcel Duchamp, Max Ernst, Elsa von Freytag-Loringhoven, George Grosz, Raoul Hausmann, John Heartfield, Emmy Hennings, Hannah Höch, Richard Huelsenbeck, Francis Picabia, Man Ray, Hans Richter, Kurt Schwitters, Sophie Taeuber-Arp, Tristan Tzara, and Beatrice Wood, among others. The movement influenced later styles like the avant-garde and downtown music movements, and groups including Surrealism, nouveau réalisme, pop art and Fluxus. | 2001-11-04T02:26:07Z | 2023-12-30T18:15:38Z | [
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] | https://en.wikipedia.org/wiki/Dada |
8,242 | Debian | Debian (/ˈdɛbiən/), also known as Debian GNU/Linux, is a Linux distribution composed of free and open-source software and proprietary software developed by the community-supported Debian Project, which was established by Ian Murdock on August 16, 1993. The first version of Debian (0.01) was released on September 15, 1993, and its first stable version (1.1) was released on June 17, 1996. The Debian Stable branch is the most popular edition for personal computers and servers. Debian is also the basis for many other distributions, like PureOS, Ubuntu, Pardus, and Linux Mint.
Debian is one of the oldest operating systems based on the Linux kernel and, as of September 2023, the second oldest Linux distribution still in active development, only behind Slackware. The project is coordinated over the Internet by a team of volunteers guided by the Debian Project Leader and three foundational documents: the Debian Social Contract, the Debian Constitution, and the Debian Free Software Guidelines. New distributions are updated continually, and the next candidate is released after a time-based freeze.
Since its founding until 2022, Debian has been developed openly and distributed freely according to some of the principles of the GNU Project. Because of this, the Free Software Foundation sponsored the project from November 1994 to November 1995. On June 16, 1997, the Debian Project founded the nonprofit organization Software in the Public Interest to continue financially supporting development.
Debian distribution codenames are based on the names of characters from the Toy Story films. Debian's unstable trunk is named after Sid, a character who regularly destroyed his toys.
First announced on August 16, 1993, Debian was founded by Ian Murdock, who initially called the system "the Debian Linux Release". The word "Debian" was formed as a portmanteau of the first name of his then-girlfriend (later ex-wife) Debra Lynn and his own first name. Before Debian's release, the Softlanding Linux System (SLS) had been a popular Linux distribution and the basis for Slackware. The perceived poor maintenance and prevalence of bugs in SLS motivated Murdock to launch a new distribution.
Debian 0.01, released on September 15, 1993, was the first of several internal releases. Version 0.90 was the first public release, providing support through mailing lists hosted at Pixar. The release included the Debian Linux Manifesto, outlining Murdock's view for the new operating system. In it he called for the creation of a distribution to be maintained "openly in the spirit of Linux and GNU."
The Debian project released the 0.9x versions in 1994 and 1995. During this time it was sponsored by the Free Software Foundation for one year. Ian Murdock delegated the base system, the core packages of Debian, to Bruce Perens and Murdock focused on the management of the growing project. The first ports to non-IA-32 architectures began in 1995, and Debian 1.1 was released in 1996. By that time and thanks to Ian Jackson, the dpkg package manager was already an essential part of Debian.
In 1996, Bruce Perens assumed the project leadership. Perens was a controversial leader, regarded as authoritarian and strongly attached to Debian. He drafted a social contract and edited suggestions from a month-long discussion into the Debian Social Contract and the Debian Free Software Guidelines. After the FSF withdrew their sponsorship in the midst of the free software vs. open source debate, Perens initiated the creation of the legal umbrella organization Software in the Public Interest instead of seeking renewed involvement with the FSF. He led the conversion of the project from a.out to ELF. He created the BusyBox program to make it possible to run a Debian installer on a single floppy disk, and wrote a new installer. By the time Debian 1.2 was released, the project had grown to nearly two hundred volunteers. Perens left the project in 1998.
Ian Jackson became the leader in 1998. Debian 2.0 introduced the second official port, m68k. During this time the first port to a non-Linux kernel, Debian GNU/Hurd, was started. On December 2, the first Debian Constitution was ratified.
From 1999, the project leader was elected yearly. The Advanced Packaging Tool was deployed with Debian 2.1. The number of applicants was overwhelming and the project established the new member process. The first Debian derivatives, namely Libranet, Corel Linux and Stormix's Storm Linux, were started in 1999. The 2.2 release in 2000 was dedicated to Joel Klecker, a developer who died of Duchenne muscular dystrophy.
In late 2000, the project reorganized the archive with new package "pools" and created the Testing distribution, made up of packages considered stable, to reduce the freeze for the next release. In the same year, developers began holding an annual conference called DebConf with talks and workshops for developers and technical users. In May 2001, Hewlett-Packard announced plans to base its Linux development on Debian.
In July 2002, the project released version 3.0, code-named Woody, the first release to include cryptographic software, a free licensed KDE and internationalization. During these last release cycles, the Debian project drew considerable criticism from the free software community because of the long time between stable releases.
Some events disturbed the project while working on Sarge, as Debian servers were attacked by fire and hackers. One of the most memorable was the Vancouver prospectus. After a meeting held in Vancouver, release manager Steve Langasek announced a plan to reduce the number of supported ports to four in order to shorten future release cycles. There was a large reaction because the proposal looked more like a decision and because such a drop would damage Debian's aim to be "the universal operating system".
The first version of the Debian-based Ubuntu, named "4.10 Warty Warthog", was released on October 20, 2004. Because it was distributed as a free download, it became one of the most popular and successful operating systems with more than "40 million users" according to Canonical Ltd. However, Murdock was critical of the differences between Ubuntu packages and Debian, stating that it leads to incompatibilities.
The 3.1 Sarge release was made in June 2005. This release updated 73% of the software and included over 9,000 new packages. A new installer with a modular design, Debian-Installer, allowed installations with RAID, XFS and LVM support, improved hardware detection, made installations easier for novice users, and was translated into almost forty languages. An installation manual and release notes were in ten and fifteen languages respectively. The efforts of Skolelinux, Debian-Med and Debian-Accessibility raised the number of packages that were educational, had a medical affiliation, and ones made for people with disabilities.
In 2006, as a result of a much-publicized dispute, Mozilla software was rebranded in Debian, with Firefox forked as Iceweasel and Thunderbird as Icedove. The Mozilla Corporation stated that software with unapproved modifications could not be distributed under the Firefox trademark. Two reasons that Debian modifies the Firefox software are to change the non-free artwork and to provide security patches. In February 2016, it was announced that Mozilla and Debian had reached an agreement and Iceweasel would revert to the name Firefox; similar agreement was anticipated for Icedove/Thunderbird.
A fund-raising experiment, Dunc-Tank, was created to solve the release cycle problem and release managers were paid to work full-time; in response, unpaid developers slowed down their work and the release was delayed. Debian 4.0 (Etch) was released in April 2007, featuring the x86-64 port and a graphical installer. Debian 5.0 (Lenny) was released in February 2009, supporting Marvell's Orion platform and netbooks such as the Asus Eee PC. The release was dedicated to Thiemo Seufer, a developer who died in a car crash.
In July 2009, the policy of time-based development freezes on a two-year cycle was announced. Time-based freezes are intended to blend the predictability of time based releases with Debian's policy of feature based releases, and to reduce overall freeze time. The Squeeze cycle was going to be especially short; however, this initial schedule was abandoned. In September 2010, the backports service became official, providing more recent versions of some software for the stable release.
Debian 6.0 (Squeeze) was released in February 2011, featuring Debian GNU/kFreeBSD as a technology preview, along with adding a dependency-based boot system, and moving problematic firmware to the non-free section. Debian 7.0 (Wheezy) was released in May 2013, featuring multiarch support. Debian 8.0 (Jessie) was released in April 2015, using systemd as the new init system. Debian 9.0 (Stretch) was released in June 2017, with nftables as a replacement for iptables, support for Flatpak apps, and MariaDB as the replacement for MySQL. Debian 10.0 (Buster) was released in July 2019, adding support for Secure Boot and enabling AppArmor by default. Debian 11.0 (Bullseye) was released in August 2021, enabling persistency in the system journal, adding support for driverless scanning, and containing kernel-level support for exFAT filesystems. Debian 12.0 (Bookworm) was released on June 10, 2023, including various improvements and features, increasing the supported Linux Kernel to version 6.1, and leveraging new "Emerald" artwork. Debian is still in development and new packages are uploaded to unstable every day.
Debian used to be released as a very large set of CDs for each architecture, but with the release of Debian 9 (Stretch) in 2017, many of the images have been dropped from the archive but remain buildable via jigdo.
Throughout Debian's lifetime, both the Debian distribution and its website have won various awards from different organizations, including Server Distribution of the Year 2011, The best Linux distro of 2011, and a Best of the Net award for October 1998.
On December 2, 2015, Microsoft announced that they would offer Debian GNU/Linux as an endorsed distribution on the Azure cloud platform. Microsoft has also added a user environment to their Windows 10 desktop operating system called Windows Subsystem for Linux that offers a Debian subset.
Debian has access to online repositories that contain over 51,000 packages. Debian officially contains only free software, but non-free software can be downloaded and installed from the Debian repositories. Debian includes popular free programs such as LibreOffice, Firefox web browser, Evolution mail, K3b disc burner, VLC media player, GIMP image editor, and Evince document viewer. Debian is a popular choice for servers, for example as the operating system component of a LAMP stack.
Several flavors of the Linux kernel exist for each port. For example, the i386 port has flavors for IA-32 PCs supporting Physical Address Extension and real-time computing, for older PCs, and for x86-64 PCs. The Linux kernel does not officially contain firmware lacking source code, although such firmware is available in non-free packages and alternative installation media.
Debian offers CD and DVD images specifically built for Xfce, GNOME, KDE, MATE, Cinnamon, LXDE, and LXQt. MATE support was added in 2014, and Cinnamon support was added with Debian 8.0 Jessie. Less common window managers such as Enlightenment, Openbox, Fluxbox, IceWM, Window Maker and others are available.
The default desktop environment of version 7.0 Wheezy was temporarily switched to Xfce, because GNOME 3 did not fit on the first CD of the set. The default for the version 8.0 Jessie was changed again to Xfce in November 2013, and back to GNOME in September 2014.
Several parts of Debian are translated into languages other than American English, including package descriptions, configuration messages, documentation and the website. The level of software localization depends on the language, ranging from the highly supported German and French to the barely translated Creek and Samoan. The Debian 10 installer is available in 76 languages.
Multimedia support has been problematic in Debian regarding codecs threatened by possible patent infringements, lacking source code, or under too restrictive licenses. Even though packages with problems related to their distribution could go into the non-free area, software such as libdvdcss is not hosted at Debian .
A notable third party repository exists, formerly named Debian-multimedia.org, providing software not present in Debian such as Windows codecs, libdvdcss and the Adobe Flash Player. Even though this repository is maintained by Christian Marillat, a Debian developer, it is not part of the project and is not hosted on a Debian server. The repository provides packages already included in Debian, interfering with the official maintenance. Eventually, project leader Stefano Zacchiroli asked Marillat to either settle an agreement about the packaging or to stop using the "Debian" name. Marillat chose the latter and renamed the repository to deb-multimedia.org. The repository was so popular that the switchover was announced by the official blog of the Debian project.
Debian offers DVD and CD images for installation that can be downloaded using BitTorrent or jigdo. Physical discs can also be bought from retailers. The full sets are made up of several discs (the amd64 port consists of 13 DVDs or 84 CDs), but only the first disc is required for installation, as the installer can retrieve software not contained in the first disc image from online repositories.
Debian offers different network installation methods. A minimal install of Debian is available via the netinst CD, whereby Debian is installed with just a base and later added software can be downloaded from the Internet. Another option is to boot the installer from the network.
The default bootstrap loader is GNU GRUB version 2, though the package name is simply grub, while version 1 was renamed to grub-legacy. This conflicts with distros (e.g., Fedora Linux), where grub version 2 is named grub2.
The default desktop may be chosen from the DVD boot menu among GNOME, KDE Plasma, Xfce and LXDE, and from special disc 1 CDs.
Debian releases live install images for CDs, DVDs and USB thumb drives, for IA-32 and x86-64 architectures, and with a choice of desktop environments. These Debian Live images allow users to boot from removable media and run Debian without affecting the contents of their computer. A full install of Debian to the computer's hard drive can be initiated from the live image environment. Personalized images can be built with the live-build tool for discs, USB drives and for network booting purposes. Installation images are hybrid on some architectures and can be used to create a bootable USB drive (Live USB).
Package management operations can be performed with different tools available on Debian, from the lowest level command dpkg to graphical front-ends like Synaptic. The recommended standard for administering packages on a Debian system is the apt toolset.
dpkg provides the low-level infrastructure for package management. The dpkg database contains the list of installed software on the current system. The dpkg command tool does not know about repositories. The command can work with local .deb package files, and information from the dpkg database.
An Advanced Packaging Tool (APT) allows administering an installed Debian system to retrieve and resolve package dependencies from repositories. APT tools share dependency information and cached packages.
GDebi is an APT tool which can be used in command-line and on the GUI. GDebi can install a local .deb file via the command line like the dpkg command, but with access to repositories to resolve dependencies. Other graphical front-ends for APT include Software Center, Synaptic and Apper.
GNOME Software is a graphical front-end for PackageKit, which itself can work on top of various software packaging systems.
The Debian Free Software Guidelines (DFSG) define the distinctive meaning of the word "free" as in "free and open-source software". Packages that comply with these guidelines, usually under the GNU General Public License, Modified BSD License or Artistic License, are included inside the main area; otherwise, they are included inside the non-free and contrib areas. These last two areas are not distributed within the official installation media, but they can be adopted manually.
Non-free includes packages that do not comply with the DFSG, such as documentation with invariant sections and proprietary software, and legally questionable packages. Contrib includes packages which do comply with the DFSG but fail other requirements. For example, they may depend on packages which are in non-free or requires such for building them.
Richard Stallman and the Free Software Foundation have criticized the Debian project for hosting the non-free repository and because the contrib and non-free areas are easily accessible, an opinion echoed by some in Debian including the former project leader Wichert Akkerman. The internal dissent in the Debian project regarding the non-free section has persisted, but the last time it came to a vote in 2004, the majority decided to keep it.
The most popular optional Linux cross-distribution package manager are graphical (front-ends) package managers. They are available within the official Debian Repository but are not installed by default. They are widely popular with both Debian users and Debian software developers who are interested in installing the most recent versions of application or using the cross-distribution package manager built-in sandbox environment. While at the same time remaining in control of the security.
Four most popular cross-distribution package managers, sorted in alphabetical order:
Three branches of Debian (also called releases, distributions or suites) are regularly maintained:
Other branches in Debian:
The snapshot archive provides older versions of the branches. They may be used to install a specific older version of some software.
Stable and oldstable get minor updates, called point releases; as of August 2021, the stable release is version 11.7, released on April 29, 2023; 7 months ago (2023-04-29), and the oldstable release is version 10.10.
The numbering scheme for the point releases up to Debian 4.0 was to include the letter r (for revision) after the main version number and then the number of the point release; for example, the latest point release of version 4.0 is 4.0r9. This scheme was chosen because a new dotted version would make the old one look obsolete and vendors would have trouble selling their CDs.
From Debian 5.0, the numbering scheme of point releases was changed, conforming to the GNU version numbering standard; the first point release of Debian 5.0 was 5.0.1 instead of 5.0r1. The numbering scheme was once again changed for the first Debian 7 update, which was version 7.1. The r scheme is no longer in use, but point release announcements include a note about not throwing away old CDs.
The Debian "swirl" logo was designed by Raul Silva in 1999 as part of a contest to replace the semi-official logo that had been used. The winner of the contest received an @Debian.org email address, and a set of Debian 2.1 install CDs for the architecture of their choice. Initially, the swirl was magic smoke arising from an also included bottle of an Arabian-style genie presented in black profile, but shortly after was reduced to the red smoke swirl for situations where space or multiple colours were not an option, and before long the bottle version effectively was superseded. There has been no official statement from the Debian project on the logo's meaning, but at the time of the logo's selection, it was suggested that the logo represented the magic smoke ( or the genie ) that made computers work.
One theory about the origin of the Debian logo is that Buzz Lightyear, the chosen character for the first named Debian release, has a swirl in his chin. Stefano Zacchiroli also suggested that this swirl is the Debian one. Buzz Lightyear's swirl is a more likely candidate as the codenames for Debian are names of Toy Story characters. The former Debian project leader Bruce Perens used to work for Pixar and is credited as a studio tools engineer on Toy Story 2 (1999).
Hardware requirements are at least those of the kernel and the GNU toolsets. Debian's recommended system requirements depend on the level of installation, which corresponds to increased numbers of installed components:
The real minimum memory requirements depend on the architecture and may be much less than the numbers listed in this table. It is possible to install Debian with 170 MB of RAM for x86-64; the installer will run in low memory mode and it is recommended to create a swap partition. The installer for z/Architecture requires about 20 MB of RAM, but relies on network hardware. Similarly, disk space requirements, which depend on the packages to be installed, can be reduced by manually selecting the packages needed. As of May 2019, no Pure Blend exists that would lower the hardware requirements easily.
It is possible to run graphical user interfaces on older or low-end systems, but the installation of window managers instead of desktop environments is recommended, as desktop environments are more resource intensive. Requirements for individual software vary widely and must be considered, with those of the base operating environment.
As of the upcoming Trixie release, the official ports are:
Unofficial ports are available as part of the unstable distribution:
Debian supports a variety of ARM-based NAS devices. The NSLU2 was supported by the installer in Debian 4.0 and 5.0, and Martin Michlmayr is providing installation tarballs since version 6.0. Other supported NAS devices are the Buffalo Kurobox Pro, GLAN Tank, Thecus N2100 and QNAP Turbo Stations.
Devices based on the Kirkwood system on a chip (SoC) are supported too, such as the SheevaPlug plug computer and OpenRD products. There are efforts to run Debian on mobile devices, but this is not a project goal yet since the Debian Linux kernel maintainers would not apply the needed patches. Nevertheless, there are packages for resource-limited systems.
There are efforts to support Debian on wireless access points. Debian is known to run on set-top boxes. Work is ongoing to support the AM335x processor, which is used in electronic point of service solutions. Debian may be customized to run on cash machines.
BeagleBoard, a low-power open-source hardware single-board computer (made by Texas Instruments) has switched to Debian Linux preloaded on its Beaglebone Black board's flash.
Roqos Core, manufactured by Roqos, is a x86-64 based IPS firewall router running Debian Linux.
Debian's policies and team efforts focus on collaborative software development and testing processes. As a result, a new major release tends to occur every two years with revision releases that fix security issues and important problems. The Debian project is a volunteer organization with three foundational documents:
Debian developers are organized in a web of trust. There are at present about one thousand active Debian developers, but it is possible to contribute to the project without being an official developer.
The project maintains official mailing lists and conferences for communication and coordination between developers. For issues with single packages and other tasks, a public bug tracking system is used by developers and end users. Internet Relay Chat is also used for communication among developers and to provide real time help.
Debian is supported by donations made to organizations authorized by the leader. The largest supporter is Software in the Public Interest, the owner of the Debian trademark, manager of the monetary donations and umbrella organization for various other community free software projects.
A Project Leader is elected once per year by the developers. The leader has special powers, but they are not absolute, and appoints delegates to perform specialized tasks. Delegates make decisions as they think is best, taking into account technical criteria and consensus. By way of a General Resolution, the developers may recall the leader, reverse a decision made by the leader or a delegate, amend foundational documents and make other binding decisions. The voting method is based on the Schulze method (Cloneproof Schwartz Sequential Dropping).
Project leadership is distributed occasionally. Branden Robinson was helped by the Project Scud, a team of developers that assisted the leader, but there were concerns that such leadership would split Debian into two developer classes. Anthony Towns created a supplemental position, Second In Charge (2IC), that shared some powers of the leader. Steve McIntyre was 2IC and had a 2IC himself.
One important role in Debian's leadership is that of a release manager. The release team sets goals for the next release, supervises the processes and decides when to release. The team is led by the next release managers and stable release managers. Release assistants were introduced in 2003.
The Debian Project has an influx of applicants wishing to become developers. These applicants must undergo a vetting process which establishes their identity, motivation, understanding of the project's principles, and technical competence. This process has become much harder throughout the years.
Debian developers join the project for many reasons. Some that have been cited include:
Debian developers may resign their positions at any time or, when deemed necessary, they can be expelled. Those who follow the retiring protocol are granted the "emeritus" status and they may regain their membership through a shortened new member process.
Each software package has a maintainer that may be either one person or a team of Debian developers and non-developer maintainers. The maintainer keeps track of upstream releases, and ensures that the package coheres with the rest of the distribution and meets the standards of quality of Debian. Packages may include modifications introduced by Debian to achieve compliance with Debian Policy, even to fix non-Debian specific bugs, although coordination with upstream developers is advised.
The maintainer releases a new version by uploading the package to the "incoming" system, which verifies the integrity of the packages and their digital signatures. If the package is found to be valid, it is installed in the package archive into an area called the "pool" and distributed every day to hundreds of mirrors worldwide. The upload must be signed using OpenPGP-compatible software. All Debian developers have individual cryptographic key pairs. Developers are responsible for any package they upload even if the packaging was prepared by another contributor.
Initially, an accepted package is only available in the unstable branch. For a package to become a candidate for the next release, it must migrate to the Testing branch by meeting the following:
Thus, a release-critical bug in a new version of a shared library on which many packages depend may prevent those packages from entering Testing, because the updated library must meet the requirements too. From the branch viewpoint, the migration process happens twice per day, rendering Testing in perpetual beta.
Periodically, the release team publishes guidelines to the developers in order to ready the release. A new release occurs after a freeze, when all important software is reasonably up-to-date in the Testing branch and any other significant issues are solved. At that time, all packages in the testing branch become the new stable branch. Although freeze dates are time-based, release dates are not, which are announced by the release managers a couple of weeks beforehand.
A version of a package can belong to more than one branch, usually testing and unstable. It is possible for a package to keep the same version between stable releases and be part of oldstable, stable, testing and unstable at the same time. Each branch can be seen as a collection of pointers into the package "pool" mentioned above.
One way to resolve the challenge of a release-critical bug in a new application version is the use of optional package managers. They allow software developers to use sandbox environments, while at the same time remaining in control of security. Another benefit of a cross-distribution package manager is that they allow application developers to directly provide updates to users without going through distributions, and without having to package and test the application separately for each distribution.
A new stable branch of Debian gets released approximately every 2 years. It will receive official support for about 3 years with update for major security or usability fixes. Point releases will be available every several months as determined by Stable Release Managers (SRM).
Debian also launched its Long Term Support (LTS) project since Debian 6 (Debian Squeeze). For each Debian release, it will receive two years of extra security updates provided by LTS Team after its End Of Life (EOL). However, no point releases will be made. Now each Debian release can receive 5 years of security support in total.
The Debian project handles security through public disclosure. Debian security advisories are compatible with the Common Vulnerabilities and Exposures dictionary, are usually coordinated with other free software vendors and are published the same day a vulnerability is made public. There used to be a security audit project that focused on packages in the stable release looking for security bugs; Steve Kemp, who started the project, retired in 2011 but resumed his activities and applied to rejoin in 2014.
The stable branch is supported by the Debian security team; oldstable is supported for one year. Although Squeeze is not officially supported, Debian is coordinating an effort to provide long-term support (LTS) until February 2016, five years after the initial release, but only for the IA-32 and x86-64 platforms. Testing is supported by the testing security team, but does not receive updates in as timely a manner as stable. Unstable's security is left for the package maintainers.
The Debian project offers documentation and tools to harden a Debian installation both manually and automatically. AppArmor support is available and enabled by default since Buster. Debian provides an optional hardening wrapper, and does not harden all of its software by default using gcc features such as PIE and buffer overflow protection, unlike operating systems such as OpenBSD, but tries to build as many packages as possible with hardening flags.
In May 2008, a Debian developer discovered that the OpenSSL package distributed with Debian and derivatives such as Ubuntu made a variety of security keys vulnerable to a random number generator attack, since only 32,767 different keys were generated. The security weakness was caused by changes made in 2006 by another Debian developer in response to memory debugger warnings. The complete resolution procedure was cumbersome because patching the security hole was not enough; it involved regenerating all affected keys and certificates.
The cost of developing all of the packages included in Debian 5.0 Lenny (323 million lines of code) has been estimated to be about US$8 billion, using one method based on the COCOMO model. As of 2016, Black Duck Open Hub estimates that the current codebase (74 million lines of code) would cost about US$1.4 billion to develop, using a different method based on the same model.
A large number of forks and derivatives have been built upon Debian over the years. Among the more notable are Ubuntu, developed by Canonical Ltd. and first released in 2004, which has surpassed Debian in popularity with desktop users; Knoppix, first released in the year 2000 and one of the first distributions optimized to boot from external storage; and Devuan, which gained attention in 2014 when it forked in disagreement over Debian's adoption of the systemd software suite, and has been mirroring Debian releases since 2017. The Linux Mint Debian Edition (LMDE) uses Debian Stable as the software source base since 2014.
Debian is one of the most popular Linux distributions, and many other distributions have been created from the Debian codebase. As of 2021, DistroWatch lists 121 active Debian derivatives. The Debian project provides its derivatives with guidelines for best practices and encourages derivatives to merge their work back into Debian.
Debian Pure Blends are subsets of a Debian release configured out-of-the-box for users with particular skills and interests. For example, Debian Jr. is made for children, while Debian Science is for researchers and scientists. The complete Debian distribution includes all available Debian Pure Blends. "Debian Blend" (without "Pure") is a term for a Debian-based distribution that strives to become part of mainstream Debian, and have its extra features included in future releases.
Debian GNU/kFreeBSD is a discontinued Debian flavor. It used the FreeBSD kernel and GNU userland. The majority of software in Debian GNU/kFreeBSD was built from the same sources as Debian, with some kernel packages from FreeBSD. The k in kFreeBSD is an abbreviation for kernel, which refers to the FreeBSD kernel. Before discontinuing the project, Debian maintained i386 and amd64 ports. The last version of Debian kFreeBSD was Debian 8 (Jessie) RC3. Debian GNU/kFreeBSD was created in 2002. It was included in Debian 6.0 (Squeeze) as a technology preview, and in Debian 7.0 (Wheezy) as an official port. Debian GNU/kFreeBSD was discontinued as an officially supported platform as of Debian 8.0. Debian developers cited OSS, pf, jails, NDIS, and ZFS as reasons for being interested in the FreeBSD kernel. It has not been updated since Debian 8. From July 2019, the operating system continues to be maintained unofficially.As of July 2023, the development of Debian GNU/kFreeBSD has officially terminated due to the lack of interest and developers.
Debian GNU/Hurd is a flavor based on the Hurd microkernel, instead of Linux. Debian GNU/Hurd has been in development since 1998, and made a formal release in May 2013, with 78% of the software packaged for Debian GNU/Linux ported to the GNU Hurd. Hurd is not yet an official Debian release, and is maintained and developed as an unofficial port. Debian GNU/Hurd is distributed as an installer CD (running the official Debian installer) or ready-to-run virtual disk image (Live CD, Live USB). The CD uses the IA-32 architecture, making it compatible with IA-32 and x86-64 PCs. The current version of Debian GNU/Hurd is 2023, published in June 2023. | [
{
"paragraph_id": 0,
"text": "Debian (/ˈdɛbiən/), also known as Debian GNU/Linux, is a Linux distribution composed of free and open-source software and proprietary software developed by the community-supported Debian Project, which was established by Ian Murdock on August 16, 1993. The first version of Debian (0.01) was released on September 15, 1993, and its first stable version (1.1) was released on June 17, 1996. The Debian Stable branch is the most popular edition for personal computers and servers. Debian is also the basis for many other distributions, like PureOS, Ubuntu, Pardus, and Linux Mint.",
"title": ""
},
{
"paragraph_id": 1,
"text": "Debian is one of the oldest operating systems based on the Linux kernel and, as of September 2023, the second oldest Linux distribution still in active development, only behind Slackware. The project is coordinated over the Internet by a team of volunteers guided by the Debian Project Leader and three foundational documents: the Debian Social Contract, the Debian Constitution, and the Debian Free Software Guidelines. New distributions are updated continually, and the next candidate is released after a time-based freeze.",
"title": ""
},
{
"paragraph_id": 2,
"text": "Since its founding until 2022, Debian has been developed openly and distributed freely according to some of the principles of the GNU Project. Because of this, the Free Software Foundation sponsored the project from November 1994 to November 1995. On June 16, 1997, the Debian Project founded the nonprofit organization Software in the Public Interest to continue financially supporting development.",
"title": ""
},
{
"paragraph_id": 3,
"text": "Debian distribution codenames are based on the names of characters from the Toy Story films. Debian's unstable trunk is named after Sid, a character who regularly destroyed his toys.",
"title": "History"
},
{
"paragraph_id": 4,
"text": "First announced on August 16, 1993, Debian was founded by Ian Murdock, who initially called the system \"the Debian Linux Release\". The word \"Debian\" was formed as a portmanteau of the first name of his then-girlfriend (later ex-wife) Debra Lynn and his own first name. Before Debian's release, the Softlanding Linux System (SLS) had been a popular Linux distribution and the basis for Slackware. The perceived poor maintenance and prevalence of bugs in SLS motivated Murdock to launch a new distribution.",
"title": "History"
},
{
"paragraph_id": 5,
"text": "Debian 0.01, released on September 15, 1993, was the first of several internal releases. Version 0.90 was the first public release, providing support through mailing lists hosted at Pixar. The release included the Debian Linux Manifesto, outlining Murdock's view for the new operating system. In it he called for the creation of a distribution to be maintained \"openly in the spirit of Linux and GNU.\"",
"title": "History"
},
{
"paragraph_id": 6,
"text": "The Debian project released the 0.9x versions in 1994 and 1995. During this time it was sponsored by the Free Software Foundation for one year. Ian Murdock delegated the base system, the core packages of Debian, to Bruce Perens and Murdock focused on the management of the growing project. The first ports to non-IA-32 architectures began in 1995, and Debian 1.1 was released in 1996. By that time and thanks to Ian Jackson, the dpkg package manager was already an essential part of Debian.",
"title": "History"
},
{
"paragraph_id": 7,
"text": "In 1996, Bruce Perens assumed the project leadership. Perens was a controversial leader, regarded as authoritarian and strongly attached to Debian. He drafted a social contract and edited suggestions from a month-long discussion into the Debian Social Contract and the Debian Free Software Guidelines. After the FSF withdrew their sponsorship in the midst of the free software vs. open source debate, Perens initiated the creation of the legal umbrella organization Software in the Public Interest instead of seeking renewed involvement with the FSF. He led the conversion of the project from a.out to ELF. He created the BusyBox program to make it possible to run a Debian installer on a single floppy disk, and wrote a new installer. By the time Debian 1.2 was released, the project had grown to nearly two hundred volunteers. Perens left the project in 1998.",
"title": "History"
},
{
"paragraph_id": 8,
"text": "Ian Jackson became the leader in 1998. Debian 2.0 introduced the second official port, m68k. During this time the first port to a non-Linux kernel, Debian GNU/Hurd, was started. On December 2, the first Debian Constitution was ratified.",
"title": "History"
},
{
"paragraph_id": 9,
"text": "From 1999, the project leader was elected yearly. The Advanced Packaging Tool was deployed with Debian 2.1. The number of applicants was overwhelming and the project established the new member process. The first Debian derivatives, namely Libranet, Corel Linux and Stormix's Storm Linux, were started in 1999. The 2.2 release in 2000 was dedicated to Joel Klecker, a developer who died of Duchenne muscular dystrophy.",
"title": "History"
},
{
"paragraph_id": 10,
"text": "In late 2000, the project reorganized the archive with new package \"pools\" and created the Testing distribution, made up of packages considered stable, to reduce the freeze for the next release. In the same year, developers began holding an annual conference called DebConf with talks and workshops for developers and technical users. In May 2001, Hewlett-Packard announced plans to base its Linux development on Debian.",
"title": "History"
},
{
"paragraph_id": 11,
"text": "In July 2002, the project released version 3.0, code-named Woody, the first release to include cryptographic software, a free licensed KDE and internationalization. During these last release cycles, the Debian project drew considerable criticism from the free software community because of the long time between stable releases.",
"title": "History"
},
{
"paragraph_id": 12,
"text": "Some events disturbed the project while working on Sarge, as Debian servers were attacked by fire and hackers. One of the most memorable was the Vancouver prospectus. After a meeting held in Vancouver, release manager Steve Langasek announced a plan to reduce the number of supported ports to four in order to shorten future release cycles. There was a large reaction because the proposal looked more like a decision and because such a drop would damage Debian's aim to be \"the universal operating system\".",
"title": "History"
},
{
"paragraph_id": 13,
"text": "The first version of the Debian-based Ubuntu, named \"4.10 Warty Warthog\", was released on October 20, 2004. Because it was distributed as a free download, it became one of the most popular and successful operating systems with more than \"40 million users\" according to Canonical Ltd. However, Murdock was critical of the differences between Ubuntu packages and Debian, stating that it leads to incompatibilities.",
"title": "History"
},
{
"paragraph_id": 14,
"text": "The 3.1 Sarge release was made in June 2005. This release updated 73% of the software and included over 9,000 new packages. A new installer with a modular design, Debian-Installer, allowed installations with RAID, XFS and LVM support, improved hardware detection, made installations easier for novice users, and was translated into almost forty languages. An installation manual and release notes were in ten and fifteen languages respectively. The efforts of Skolelinux, Debian-Med and Debian-Accessibility raised the number of packages that were educational, had a medical affiliation, and ones made for people with disabilities.",
"title": "History"
},
{
"paragraph_id": 15,
"text": "In 2006, as a result of a much-publicized dispute, Mozilla software was rebranded in Debian, with Firefox forked as Iceweasel and Thunderbird as Icedove. The Mozilla Corporation stated that software with unapproved modifications could not be distributed under the Firefox trademark. Two reasons that Debian modifies the Firefox software are to change the non-free artwork and to provide security patches. In February 2016, it was announced that Mozilla and Debian had reached an agreement and Iceweasel would revert to the name Firefox; similar agreement was anticipated for Icedove/Thunderbird.",
"title": "History"
},
{
"paragraph_id": 16,
"text": "A fund-raising experiment, Dunc-Tank, was created to solve the release cycle problem and release managers were paid to work full-time; in response, unpaid developers slowed down their work and the release was delayed. Debian 4.0 (Etch) was released in April 2007, featuring the x86-64 port and a graphical installer. Debian 5.0 (Lenny) was released in February 2009, supporting Marvell's Orion platform and netbooks such as the Asus Eee PC. The release was dedicated to Thiemo Seufer, a developer who died in a car crash.",
"title": "History"
},
{
"paragraph_id": 17,
"text": "In July 2009, the policy of time-based development freezes on a two-year cycle was announced. Time-based freezes are intended to blend the predictability of time based releases with Debian's policy of feature based releases, and to reduce overall freeze time. The Squeeze cycle was going to be especially short; however, this initial schedule was abandoned. In September 2010, the backports service became official, providing more recent versions of some software for the stable release.",
"title": "History"
},
{
"paragraph_id": 18,
"text": "Debian 6.0 (Squeeze) was released in February 2011, featuring Debian GNU/kFreeBSD as a technology preview, along with adding a dependency-based boot system, and moving problematic firmware to the non-free section. Debian 7.0 (Wheezy) was released in May 2013, featuring multiarch support. Debian 8.0 (Jessie) was released in April 2015, using systemd as the new init system. Debian 9.0 (Stretch) was released in June 2017, with nftables as a replacement for iptables, support for Flatpak apps, and MariaDB as the replacement for MySQL. Debian 10.0 (Buster) was released in July 2019, adding support for Secure Boot and enabling AppArmor by default. Debian 11.0 (Bullseye) was released in August 2021, enabling persistency in the system journal, adding support for driverless scanning, and containing kernel-level support for exFAT filesystems. Debian 12.0 (Bookworm) was released on June 10, 2023, including various improvements and features, increasing the supported Linux Kernel to version 6.1, and leveraging new \"Emerald\" artwork. Debian is still in development and new packages are uploaded to unstable every day.",
"title": "History"
},
{
"paragraph_id": 19,
"text": "Debian used to be released as a very large set of CDs for each architecture, but with the release of Debian 9 (Stretch) in 2017, many of the images have been dropped from the archive but remain buildable via jigdo.",
"title": "History"
},
{
"paragraph_id": 20,
"text": "Throughout Debian's lifetime, both the Debian distribution and its website have won various awards from different organizations, including Server Distribution of the Year 2011, The best Linux distro of 2011, and a Best of the Net award for October 1998.",
"title": "History"
},
{
"paragraph_id": 21,
"text": "On December 2, 2015, Microsoft announced that they would offer Debian GNU/Linux as an endorsed distribution on the Azure cloud platform. Microsoft has also added a user environment to their Windows 10 desktop operating system called Windows Subsystem for Linux that offers a Debian subset.",
"title": "History"
},
{
"paragraph_id": 22,
"text": "Debian has access to online repositories that contain over 51,000 packages. Debian officially contains only free software, but non-free software can be downloaded and installed from the Debian repositories. Debian includes popular free programs such as LibreOffice, Firefox web browser, Evolution mail, K3b disc burner, VLC media player, GIMP image editor, and Evince document viewer. Debian is a popular choice for servers, for example as the operating system component of a LAMP stack.",
"title": "Features"
},
{
"paragraph_id": 23,
"text": "Several flavors of the Linux kernel exist for each port. For example, the i386 port has flavors for IA-32 PCs supporting Physical Address Extension and real-time computing, for older PCs, and for x86-64 PCs. The Linux kernel does not officially contain firmware lacking source code, although such firmware is available in non-free packages and alternative installation media.",
"title": "Features"
},
{
"paragraph_id": 24,
"text": "Debian offers CD and DVD images specifically built for Xfce, GNOME, KDE, MATE, Cinnamon, LXDE, and LXQt. MATE support was added in 2014, and Cinnamon support was added with Debian 8.0 Jessie. Less common window managers such as Enlightenment, Openbox, Fluxbox, IceWM, Window Maker and others are available.",
"title": "Features"
},
{
"paragraph_id": 25,
"text": "The default desktop environment of version 7.0 Wheezy was temporarily switched to Xfce, because GNOME 3 did not fit on the first CD of the set. The default for the version 8.0 Jessie was changed again to Xfce in November 2013, and back to GNOME in September 2014.",
"title": "Features"
},
{
"paragraph_id": 26,
"text": "Several parts of Debian are translated into languages other than American English, including package descriptions, configuration messages, documentation and the website. The level of software localization depends on the language, ranging from the highly supported German and French to the barely translated Creek and Samoan. The Debian 10 installer is available in 76 languages.",
"title": "Features"
},
{
"paragraph_id": 27,
"text": "Multimedia support has been problematic in Debian regarding codecs threatened by possible patent infringements, lacking source code, or under too restrictive licenses. Even though packages with problems related to their distribution could go into the non-free area, software such as libdvdcss is not hosted at Debian .",
"title": "Features"
},
{
"paragraph_id": 28,
"text": "A notable third party repository exists, formerly named Debian-multimedia.org, providing software not present in Debian such as Windows codecs, libdvdcss and the Adobe Flash Player. Even though this repository is maintained by Christian Marillat, a Debian developer, it is not part of the project and is not hosted on a Debian server. The repository provides packages already included in Debian, interfering with the official maintenance. Eventually, project leader Stefano Zacchiroli asked Marillat to either settle an agreement about the packaging or to stop using the \"Debian\" name. Marillat chose the latter and renamed the repository to deb-multimedia.org. The repository was so popular that the switchover was announced by the official blog of the Debian project.",
"title": "Features"
},
{
"paragraph_id": 29,
"text": "Debian offers DVD and CD images for installation that can be downloaded using BitTorrent or jigdo. Physical discs can also be bought from retailers. The full sets are made up of several discs (the amd64 port consists of 13 DVDs or 84 CDs), but only the first disc is required for installation, as the installer can retrieve software not contained in the first disc image from online repositories.",
"title": "Distribution"
},
{
"paragraph_id": 30,
"text": "Debian offers different network installation methods. A minimal install of Debian is available via the netinst CD, whereby Debian is installed with just a base and later added software can be downloaded from the Internet. Another option is to boot the installer from the network.",
"title": "Distribution"
},
{
"paragraph_id": 31,
"text": "The default bootstrap loader is GNU GRUB version 2, though the package name is simply grub, while version 1 was renamed to grub-legacy. This conflicts with distros (e.g., Fedora Linux), where grub version 2 is named grub2.",
"title": "Distribution"
},
{
"paragraph_id": 32,
"text": "The default desktop may be chosen from the DVD boot menu among GNOME, KDE Plasma, Xfce and LXDE, and from special disc 1 CDs.",
"title": "Distribution"
},
{
"paragraph_id": 33,
"text": "Debian releases live install images for CDs, DVDs and USB thumb drives, for IA-32 and x86-64 architectures, and with a choice of desktop environments. These Debian Live images allow users to boot from removable media and run Debian without affecting the contents of their computer. A full install of Debian to the computer's hard drive can be initiated from the live image environment. Personalized images can be built with the live-build tool for discs, USB drives and for network booting purposes. Installation images are hybrid on some architectures and can be used to create a bootable USB drive (Live USB).",
"title": "Distribution"
},
{
"paragraph_id": 34,
"text": "Package management operations can be performed with different tools available on Debian, from the lowest level command dpkg to graphical front-ends like Synaptic. The recommended standard for administering packages on a Debian system is the apt toolset.",
"title": "Packages"
},
{
"paragraph_id": 35,
"text": "dpkg provides the low-level infrastructure for package management. The dpkg database contains the list of installed software on the current system. The dpkg command tool does not know about repositories. The command can work with local .deb package files, and information from the dpkg database.",
"title": "Packages"
},
{
"paragraph_id": 36,
"text": "An Advanced Packaging Tool (APT) allows administering an installed Debian system to retrieve and resolve package dependencies from repositories. APT tools share dependency information and cached packages.",
"title": "Packages"
},
{
"paragraph_id": 37,
"text": "GDebi is an APT tool which can be used in command-line and on the GUI. GDebi can install a local .deb file via the command line like the dpkg command, but with access to repositories to resolve dependencies. Other graphical front-ends for APT include Software Center, Synaptic and Apper.",
"title": "Packages"
},
{
"paragraph_id": 38,
"text": "GNOME Software is a graphical front-end for PackageKit, which itself can work on top of various software packaging systems.",
"title": "Packages"
},
{
"paragraph_id": 39,
"text": "The Debian Free Software Guidelines (DFSG) define the distinctive meaning of the word \"free\" as in \"free and open-source software\". Packages that comply with these guidelines, usually under the GNU General Public License, Modified BSD License or Artistic License, are included inside the main area; otherwise, they are included inside the non-free and contrib areas. These last two areas are not distributed within the official installation media, but they can be adopted manually.",
"title": "Packages"
},
{
"paragraph_id": 40,
"text": "Non-free includes packages that do not comply with the DFSG, such as documentation with invariant sections and proprietary software, and legally questionable packages. Contrib includes packages which do comply with the DFSG but fail other requirements. For example, they may depend on packages which are in non-free or requires such for building them.",
"title": "Packages"
},
{
"paragraph_id": 41,
"text": "Richard Stallman and the Free Software Foundation have criticized the Debian project for hosting the non-free repository and because the contrib and non-free areas are easily accessible, an opinion echoed by some in Debian including the former project leader Wichert Akkerman. The internal dissent in the Debian project regarding the non-free section has persisted, but the last time it came to a vote in 2004, the majority decided to keep it.",
"title": "Packages"
},
{
"paragraph_id": 42,
"text": "The most popular optional Linux cross-distribution package manager are graphical (front-ends) package managers. They are available within the official Debian Repository but are not installed by default. They are widely popular with both Debian users and Debian software developers who are interested in installing the most recent versions of application or using the cross-distribution package manager built-in sandbox environment. While at the same time remaining in control of the security.",
"title": "Packages"
},
{
"paragraph_id": 43,
"text": "Four most popular cross-distribution package managers, sorted in alphabetical order:",
"title": "Packages"
},
{
"paragraph_id": 44,
"text": "Three branches of Debian (also called releases, distributions or suites) are regularly maintained:",
"title": "Branches"
},
{
"paragraph_id": 45,
"text": "Other branches in Debian:",
"title": "Branches"
},
{
"paragraph_id": 46,
"text": "The snapshot archive provides older versions of the branches. They may be used to install a specific older version of some software.",
"title": "Branches"
},
{
"paragraph_id": 47,
"text": "Stable and oldstable get minor updates, called point releases; as of August 2021, the stable release is version 11.7, released on April 29, 2023; 7 months ago (2023-04-29), and the oldstable release is version 10.10.",
"title": "Branches"
},
{
"paragraph_id": 48,
"text": "The numbering scheme for the point releases up to Debian 4.0 was to include the letter r (for revision) after the main version number and then the number of the point release; for example, the latest point release of version 4.0 is 4.0r9. This scheme was chosen because a new dotted version would make the old one look obsolete and vendors would have trouble selling their CDs.",
"title": "Branches"
},
{
"paragraph_id": 49,
"text": "From Debian 5.0, the numbering scheme of point releases was changed, conforming to the GNU version numbering standard; the first point release of Debian 5.0 was 5.0.1 instead of 5.0r1. The numbering scheme was once again changed for the first Debian 7 update, which was version 7.1. The r scheme is no longer in use, but point release announcements include a note about not throwing away old CDs.",
"title": "Branches"
},
{
"paragraph_id": 50,
"text": "The Debian \"swirl\" logo was designed by Raul Silva in 1999 as part of a contest to replace the semi-official logo that had been used. The winner of the contest received an @Debian.org email address, and a set of Debian 2.1 install CDs for the architecture of their choice. Initially, the swirl was magic smoke arising from an also included bottle of an Arabian-style genie presented in black profile, but shortly after was reduced to the red smoke swirl for situations where space or multiple colours were not an option, and before long the bottle version effectively was superseded. There has been no official statement from the Debian project on the logo's meaning, but at the time of the logo's selection, it was suggested that the logo represented the magic smoke ( or the genie ) that made computers work.",
"title": "Branding"
},
{
"paragraph_id": 51,
"text": "One theory about the origin of the Debian logo is that Buzz Lightyear, the chosen character for the first named Debian release, has a swirl in his chin. Stefano Zacchiroli also suggested that this swirl is the Debian one. Buzz Lightyear's swirl is a more likely candidate as the codenames for Debian are names of Toy Story characters. The former Debian project leader Bruce Perens used to work for Pixar and is credited as a studio tools engineer on Toy Story 2 (1999).",
"title": "Branding"
},
{
"paragraph_id": 52,
"text": "Hardware requirements are at least those of the kernel and the GNU toolsets. Debian's recommended system requirements depend on the level of installation, which corresponds to increased numbers of installed components:",
"title": "Hardware"
},
{
"paragraph_id": 53,
"text": "The real minimum memory requirements depend on the architecture and may be much less than the numbers listed in this table. It is possible to install Debian with 170 MB of RAM for x86-64; the installer will run in low memory mode and it is recommended to create a swap partition. The installer for z/Architecture requires about 20 MB of RAM, but relies on network hardware. Similarly, disk space requirements, which depend on the packages to be installed, can be reduced by manually selecting the packages needed. As of May 2019, no Pure Blend exists that would lower the hardware requirements easily.",
"title": "Hardware"
},
{
"paragraph_id": 54,
"text": "It is possible to run graphical user interfaces on older or low-end systems, but the installation of window managers instead of desktop environments is recommended, as desktop environments are more resource intensive. Requirements for individual software vary widely and must be considered, with those of the base operating environment.",
"title": "Hardware"
},
{
"paragraph_id": 55,
"text": "As of the upcoming Trixie release, the official ports are:",
"title": "Hardware"
},
{
"paragraph_id": 56,
"text": "Unofficial ports are available as part of the unstable distribution:",
"title": "Hardware"
},
{
"paragraph_id": 57,
"text": "Debian supports a variety of ARM-based NAS devices. The NSLU2 was supported by the installer in Debian 4.0 and 5.0, and Martin Michlmayr is providing installation tarballs since version 6.0. Other supported NAS devices are the Buffalo Kurobox Pro, GLAN Tank, Thecus N2100 and QNAP Turbo Stations.",
"title": "Hardware"
},
{
"paragraph_id": 58,
"text": "Devices based on the Kirkwood system on a chip (SoC) are supported too, such as the SheevaPlug plug computer and OpenRD products. There are efforts to run Debian on mobile devices, but this is not a project goal yet since the Debian Linux kernel maintainers would not apply the needed patches. Nevertheless, there are packages for resource-limited systems.",
"title": "Hardware"
},
{
"paragraph_id": 59,
"text": "There are efforts to support Debian on wireless access points. Debian is known to run on set-top boxes. Work is ongoing to support the AM335x processor, which is used in electronic point of service solutions. Debian may be customized to run on cash machines.",
"title": "Hardware"
},
{
"paragraph_id": 60,
"text": "BeagleBoard, a low-power open-source hardware single-board computer (made by Texas Instruments) has switched to Debian Linux preloaded on its Beaglebone Black board's flash.",
"title": "Hardware"
},
{
"paragraph_id": 61,
"text": "Roqos Core, manufactured by Roqos, is a x86-64 based IPS firewall router running Debian Linux.",
"title": "Hardware"
},
{
"paragraph_id": 62,
"text": "Debian's policies and team efforts focus on collaborative software development and testing processes. As a result, a new major release tends to occur every two years with revision releases that fix security issues and important problems. The Debian project is a volunteer organization with three foundational documents:",
"title": "Organization"
},
{
"paragraph_id": 63,
"text": "Debian developers are organized in a web of trust. There are at present about one thousand active Debian developers, but it is possible to contribute to the project without being an official developer.",
"title": "Organization"
},
{
"paragraph_id": 64,
"text": "The project maintains official mailing lists and conferences for communication and coordination between developers. For issues with single packages and other tasks, a public bug tracking system is used by developers and end users. Internet Relay Chat is also used for communication among developers and to provide real time help.",
"title": "Organization"
},
{
"paragraph_id": 65,
"text": "Debian is supported by donations made to organizations authorized by the leader. The largest supporter is Software in the Public Interest, the owner of the Debian trademark, manager of the monetary donations and umbrella organization for various other community free software projects.",
"title": "Organization"
},
{
"paragraph_id": 66,
"text": "A Project Leader is elected once per year by the developers. The leader has special powers, but they are not absolute, and appoints delegates to perform specialized tasks. Delegates make decisions as they think is best, taking into account technical criteria and consensus. By way of a General Resolution, the developers may recall the leader, reverse a decision made by the leader or a delegate, amend foundational documents and make other binding decisions. The voting method is based on the Schulze method (Cloneproof Schwartz Sequential Dropping).",
"title": "Organization"
},
{
"paragraph_id": 67,
"text": "Project leadership is distributed occasionally. Branden Robinson was helped by the Project Scud, a team of developers that assisted the leader, but there were concerns that such leadership would split Debian into two developer classes. Anthony Towns created a supplemental position, Second In Charge (2IC), that shared some powers of the leader. Steve McIntyre was 2IC and had a 2IC himself.",
"title": "Organization"
},
{
"paragraph_id": 68,
"text": "One important role in Debian's leadership is that of a release manager. The release team sets goals for the next release, supervises the processes and decides when to release. The team is led by the next release managers and stable release managers. Release assistants were introduced in 2003.",
"title": "Organization"
},
{
"paragraph_id": 69,
"text": "The Debian Project has an influx of applicants wishing to become developers. These applicants must undergo a vetting process which establishes their identity, motivation, understanding of the project's principles, and technical competence. This process has become much harder throughout the years.",
"title": "Organization"
},
{
"paragraph_id": 70,
"text": "Debian developers join the project for many reasons. Some that have been cited include:",
"title": "Organization"
},
{
"paragraph_id": 71,
"text": "Debian developers may resign their positions at any time or, when deemed necessary, they can be expelled. Those who follow the retiring protocol are granted the \"emeritus\" status and they may regain their membership through a shortened new member process.",
"title": "Organization"
},
{
"paragraph_id": 72,
"text": "Each software package has a maintainer that may be either one person or a team of Debian developers and non-developer maintainers. The maintainer keeps track of upstream releases, and ensures that the package coheres with the rest of the distribution and meets the standards of quality of Debian. Packages may include modifications introduced by Debian to achieve compliance with Debian Policy, even to fix non-Debian specific bugs, although coordination with upstream developers is advised.",
"title": "Development"
},
{
"paragraph_id": 73,
"text": "The maintainer releases a new version by uploading the package to the \"incoming\" system, which verifies the integrity of the packages and their digital signatures. If the package is found to be valid, it is installed in the package archive into an area called the \"pool\" and distributed every day to hundreds of mirrors worldwide. The upload must be signed using OpenPGP-compatible software. All Debian developers have individual cryptographic key pairs. Developers are responsible for any package they upload even if the packaging was prepared by another contributor.",
"title": "Development"
},
{
"paragraph_id": 74,
"text": "Initially, an accepted package is only available in the unstable branch. For a package to become a candidate for the next release, it must migrate to the Testing branch by meeting the following:",
"title": "Development"
},
{
"paragraph_id": 75,
"text": "Thus, a release-critical bug in a new version of a shared library on which many packages depend may prevent those packages from entering Testing, because the updated library must meet the requirements too. From the branch viewpoint, the migration process happens twice per day, rendering Testing in perpetual beta.",
"title": "Development"
},
{
"paragraph_id": 76,
"text": "Periodically, the release team publishes guidelines to the developers in order to ready the release. A new release occurs after a freeze, when all important software is reasonably up-to-date in the Testing branch and any other significant issues are solved. At that time, all packages in the testing branch become the new stable branch. Although freeze dates are time-based, release dates are not, which are announced by the release managers a couple of weeks beforehand.",
"title": "Development"
},
{
"paragraph_id": 77,
"text": "A version of a package can belong to more than one branch, usually testing and unstable. It is possible for a package to keep the same version between stable releases and be part of oldstable, stable, testing and unstable at the same time. Each branch can be seen as a collection of pointers into the package \"pool\" mentioned above.",
"title": "Development"
},
{
"paragraph_id": 78,
"text": "One way to resolve the challenge of a release-critical bug in a new application version is the use of optional package managers. They allow software developers to use sandbox environments, while at the same time remaining in control of security. Another benefit of a cross-distribution package manager is that they allow application developers to directly provide updates to users without going through distributions, and without having to package and test the application separately for each distribution.",
"title": "Development"
},
{
"paragraph_id": 79,
"text": "A new stable branch of Debian gets released approximately every 2 years. It will receive official support for about 3 years with update for major security or usability fixes. Point releases will be available every several months as determined by Stable Release Managers (SRM).",
"title": "Development"
},
{
"paragraph_id": 80,
"text": "Debian also launched its Long Term Support (LTS) project since Debian 6 (Debian Squeeze). For each Debian release, it will receive two years of extra security updates provided by LTS Team after its End Of Life (EOL). However, no point releases will be made. Now each Debian release can receive 5 years of security support in total.",
"title": "Development"
},
{
"paragraph_id": 81,
"text": "The Debian project handles security through public disclosure. Debian security advisories are compatible with the Common Vulnerabilities and Exposures dictionary, are usually coordinated with other free software vendors and are published the same day a vulnerability is made public. There used to be a security audit project that focused on packages in the stable release looking for security bugs; Steve Kemp, who started the project, retired in 2011 but resumed his activities and applied to rejoin in 2014.",
"title": "Development"
},
{
"paragraph_id": 82,
"text": "The stable branch is supported by the Debian security team; oldstable is supported for one year. Although Squeeze is not officially supported, Debian is coordinating an effort to provide long-term support (LTS) until February 2016, five years after the initial release, but only for the IA-32 and x86-64 platforms. Testing is supported by the testing security team, but does not receive updates in as timely a manner as stable. Unstable's security is left for the package maintainers.",
"title": "Development"
},
{
"paragraph_id": 83,
"text": "The Debian project offers documentation and tools to harden a Debian installation both manually and automatically. AppArmor support is available and enabled by default since Buster. Debian provides an optional hardening wrapper, and does not harden all of its software by default using gcc features such as PIE and buffer overflow protection, unlike operating systems such as OpenBSD, but tries to build as many packages as possible with hardening flags.",
"title": "Development"
},
{
"paragraph_id": 84,
"text": "In May 2008, a Debian developer discovered that the OpenSSL package distributed with Debian and derivatives such as Ubuntu made a variety of security keys vulnerable to a random number generator attack, since only 32,767 different keys were generated. The security weakness was caused by changes made in 2006 by another Debian developer in response to memory debugger warnings. The complete resolution procedure was cumbersome because patching the security hole was not enough; it involved regenerating all affected keys and certificates.",
"title": "Development"
},
{
"paragraph_id": 85,
"text": "The cost of developing all of the packages included in Debian 5.0 Lenny (323 million lines of code) has been estimated to be about US$8 billion, using one method based on the COCOMO model. As of 2016, Black Duck Open Hub estimates that the current codebase (74 million lines of code) would cost about US$1.4 billion to develop, using a different method based on the same model.",
"title": "Development"
},
{
"paragraph_id": 86,
"text": "A large number of forks and derivatives have been built upon Debian over the years. Among the more notable are Ubuntu, developed by Canonical Ltd. and first released in 2004, which has surpassed Debian in popularity with desktop users; Knoppix, first released in the year 2000 and one of the first distributions optimized to boot from external storage; and Devuan, which gained attention in 2014 when it forked in disagreement over Debian's adoption of the systemd software suite, and has been mirroring Debian releases since 2017. The Linux Mint Debian Edition (LMDE) uses Debian Stable as the software source base since 2014.",
"title": "Forks and derivatives"
},
{
"paragraph_id": 87,
"text": "Debian is one of the most popular Linux distributions, and many other distributions have been created from the Debian codebase. As of 2021, DistroWatch lists 121 active Debian derivatives. The Debian project provides its derivatives with guidelines for best practices and encourages derivatives to merge their work back into Debian.",
"title": "Forks and derivatives"
},
{
"paragraph_id": 88,
"text": "Debian Pure Blends are subsets of a Debian release configured out-of-the-box for users with particular skills and interests. For example, Debian Jr. is made for children, while Debian Science is for researchers and scientists. The complete Debian distribution includes all available Debian Pure Blends. \"Debian Blend\" (without \"Pure\") is a term for a Debian-based distribution that strives to become part of mainstream Debian, and have its extra features included in future releases.",
"title": "Forks and derivatives"
},
{
"paragraph_id": 89,
"text": "Debian GNU/kFreeBSD is a discontinued Debian flavor. It used the FreeBSD kernel and GNU userland. The majority of software in Debian GNU/kFreeBSD was built from the same sources as Debian, with some kernel packages from FreeBSD. The k in kFreeBSD is an abbreviation for kernel, which refers to the FreeBSD kernel. Before discontinuing the project, Debian maintained i386 and amd64 ports. The last version of Debian kFreeBSD was Debian 8 (Jessie) RC3. Debian GNU/kFreeBSD was created in 2002. It was included in Debian 6.0 (Squeeze) as a technology preview, and in Debian 7.0 (Wheezy) as an official port. Debian GNU/kFreeBSD was discontinued as an officially supported platform as of Debian 8.0. Debian developers cited OSS, pf, jails, NDIS, and ZFS as reasons for being interested in the FreeBSD kernel. It has not been updated since Debian 8. From July 2019, the operating system continues to be maintained unofficially.As of July 2023, the development of Debian GNU/kFreeBSD has officially terminated due to the lack of interest and developers.",
"title": "Forks and derivatives"
},
{
"paragraph_id": 90,
"text": "Debian GNU/Hurd is a flavor based on the Hurd microkernel, instead of Linux. Debian GNU/Hurd has been in development since 1998, and made a formal release in May 2013, with 78% of the software packaged for Debian GNU/Linux ported to the GNU Hurd. Hurd is not yet an official Debian release, and is maintained and developed as an unofficial port. Debian GNU/Hurd is distributed as an installer CD (running the official Debian installer) or ready-to-run virtual disk image (Live CD, Live USB). The CD uses the IA-32 architecture, making it compatible with IA-32 and x86-64 PCs. The current version of Debian GNU/Hurd is 2023, published in June 2023.",
"title": "Forks and derivatives"
}
] | Debian, also known as Debian GNU/Linux, is a Linux distribution composed of free and open-source software and proprietary software developed by the community-supported Debian Project, which was established by Ian Murdock on August 16, 1993. The first version of Debian (0.01) was released on September 15, 1993, and its first stable version (1.1) was released on June 17, 1996. The Debian Stable branch is the most popular edition for personal computers and servers. Debian is also the basis for many other distributions, like PureOS, Ubuntu, Pardus, and Linux Mint. Debian is one of the oldest operating systems based on the Linux kernel and, as of September 2023, the second oldest Linux distribution still in active development, only behind Slackware. The project is coordinated over the Internet by a team of volunteers guided by the Debian Project Leader and three foundational documents: the Debian Social Contract, the Debian Constitution, and the Debian Free Software Guidelines. New distributions are updated continually, and the next candidate is released after a time-based freeze. Since its founding until 2022, Debian has been developed openly and distributed freely according to some of the principles of the GNU Project. Because of this, the Free Software Foundation sponsored the project from November 1994 to November 1995. On June 16, 1997, the Debian Project founded the nonprofit organization Software in the Public Interest to continue financially supporting development. | 2001-10-02T05:49:10Z | 2023-12-30T23:35:47Z | [
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] | https://en.wikipedia.org/wiki/Debian |
8,243 | Doonesbury | Doonesbury is a comic strip by American cartoonist Garry Trudeau that chronicles the adventures and lives of an array of characters of various ages, professions, and backgrounds, from the President of the United States to the title character, Michael Doonesbury, who has progressed from a college student to a youthful senior citizen over the decades.
Created in "the throes of '60s and '70s counterculture", and frequently political in nature, Doonesbury features characters representing a range of affiliations, but the cartoon is noted for a liberal viewpoint. The name "Doonesbury" is a combination of the word doone (American prep school slang for someone who is clueless, inattentive, or careless) and the surname of Charles Pillsbury, Trudeau's roommate at Yale University.
Doonesbury is written and penciled by Garry Trudeau, then inked and lettered by an assistant, Don Carlton, then Todd Pound. Sunday strips are colored by George Corsillo. Doonesbury was a daily strip through most of its existence, but since February 2014 it has run repeat strips Monday through Saturday, and new strips on Sunday.
Doonesbury began as a continuation of Bull Tales, which appeared in the Yale University student newspaper, the Yale Daily News, from 1968 to 1970. It focused on local campus events at Yale.
Doonesbury proper debuted as a daily strip in twenty-eight newspapers on October 26, 1970 (it being the first strip from Universal Press Syndicate). A Sunday strip began on March 21, 1971. Many of the early strips were reprints of the Bull Tales cartoons, with some changes to the drawings and plots. B. D.'s helmet changed from having a "Y" (for Yale) to a star (for the fictional Walden College). Mike and B. D. started Doonesbury as roommates; they were not roommates in Bull Tales.
Doonesbury became known for its social and political commentary. By the 2010s, it was syndicated in approximately 1,400 newspapers worldwide.
In May 1975, Doonesbury became the first daily comic strip to win a Pulitzer Prize, taking the award for Editorial Cartooning. That year, U.S. President Gerald Ford told the Radio and Television Correspondents' Association at their annual dinner, "There are only three major vehicles to keep us informed as to what is going on in Washington: the electronic media, the print media, and Doonesbury, not necessarily in that order."
Trudeau took a 22-month hiatus, from January 2, 1983, to September 30, 1984. Before the break in the strip, the characters were eternal college students, living in a commune together near Walden College, which was modeled after Trudeau's alma mater, Yale. During the break, Trudeau helped create a Broadway musical of the strip, showing the graduation of the main characters. The Broadway adaptation opened at the Biltmore Theatre on November 21, 1983, and played 104 performances. Elizabeth Swados composed the music for Trudeau's book and lyrics.
The strip resumed some time after the events in the musical, with further changes having taken place after the end of the musical's plot. Mike, Mark, Zonker, B.D., and Boopsie were all now graduates; B.D. and Boopsie were living in Malibu, California, where B.D. was a third-string quarterback for the Los Angeles Rams, and Boopsie was making a living from walk-on and cameo roles. Mark was living in Washington, D.C., working for National Public Radio. Michael and J.J. had gotten married, and Mike had dropped out of business school to start work in an advertising agency in New York City. Zonker, still not ready for the "real world", was living with Mike and J.J. until he was accepted as a medical student at his Uncle Duke's "Baby Doc College" in Haiti.
Prior to the hiatus, the strip's characters had aged only slightly. But when Trudeau returned to Doonesbury, the characters began to age in something close to real time, as in Gasoline Alley and For Better or for Worse, Since then, the main characters' ages and career developments have tracked that of standard media portrayals of baby boomers, with jobs in advertising, law enforcement, and the dot-com boom. Current events are mirrored through the original characters, their offspring (the "second generation"), and occasional new characters.
Garry Trudeau received the National Cartoonist Society Newspaper Comic Strip Award for 1994, and their Reuben Award for 1995 for his work on the strip.
Doonesbury's syndicate, Universal Uclick, announced on May 29, 2013, that the comic strip would go on hiatus from June 10 to Labor Day of that year while Garry Trudeau worked on his streaming video comedy Alpha House, which was picked up by Amazon Studios. "Doonesbury Flashbacks" were offered during those weeks, but due to the unusually long hiatus, some newspapers opted to run different comic strips instead. Sunday strips returned as scheduled, but the daily strip's hiatus was extended until November 2013.
After Alpha House was renewed for a second season in February 2014, Trudeau announced that he would now produce only Sunday strips for the foreseeable future. Since March 3, 2014, the strip has offered reruns starting from the very beginning of its history as opposed to the recent ones that re-run when Trudeau is on vacation. Alpha House was cancelled in 2016, but Trudeau did not return to drawing Monday-to-Saturday strips, and continued his Sunday-only schedule.
In a 2018 interview with Rolling Stone, Trudeau said that while Donald Trump appears in only a limited number of strips, "for the last two years, he's been subtext in almost all of them."
In 1977, Trudeau wrote a script for a 26-minute animated special, A Doonesbury Special, which was produced and directed by Trudeau along with John Hubley (who died during the storyboarding stage) and Faith Hubley. The special was first broadcast by NBC on November 27, 1977. It won a Special Jury Award at the Cannes International Film Festival for best short film, and received an Oscar nomination (for best animated short film), both in 1978. Voice actors for the special included Barbara Harris, William Sloane Coffin, Jr., Jack Gilford and Will Jordan. Also included were "Stop in the Middle" and "I Do Believe", two songs "sung" by the character Jimmy Thudpucker (actually actor/singer/songwriter/producer James Allen "Jimmy" Brewer), also part of the "Special". While the compositions and performances were credited to "Jimmy Thudpucker", they were in fact co-written and sung by Brewer, who also co-wrote and provided the vocals for "Ginny's Song", a 1976 single on the Warner Bros. label, and Jimmy Thudpucker's Greatest Hits, an LP released by Windsong Records, John Denver's subsidiary of RCA Records.
With the exception of Walden College, Trudeau has frequently used real-life settings, based on real scenarios, but with fictional results. Because of lead times, real-world events have rendered some of Trudeau's comics unusable, such as a 1973 series featuring John Ehrlichman, a 1989 series set in Tiananmen Square in Beijing, China, a 1993 series involving Zoë Baird, and a 2005 series involving Harriet Miers. Trudeau has also displayed fluency in various forms of jargon, including those of real estate agents, flight attendants, computer scientists, journalists, presidential aides, and soldiers in Iraq.
The unnamed college attended by the main characters was later given the name "Walden College", revealed to be in Connecticut (the same state as Yale), and depicted as devolving into a third-rate institution under the weight of grade inflation, slipping academic standards, and the end of tenure, issues that Trudeau has consistently revisited since the original characters graduated. Some of the second generation of Doonesbury characters have attended Walden, a venue Trudeau uses to advance his concerns about academic standards in the United States.
President King, the leader of Walden College, was originally intended as a parody of Kingman Brewster, President of Yale, but all that remains of that is a certain physical resemblance.
Even though Doonesbury frequently features real-life U.S. politicians, they are rarely depicted with their real faces. Originally, strips featuring the President of the United States would show an external view of the White House, with dialogue emerging from inside. During the Gerald Ford administration, characters would be shown speaking to Ford at press conferences, and fictional dialogue supposedly spoken by Ford would be written as coming "off-panel". Similarly, while having several characters as students in a class taught by Henry Kissinger, the dialogue made up for Kissinger would also come from "off-panel" (although Kissinger had earlier appeared as a character with his face shown in a 1972 series of strips in which he met Mark Slackmeyer while the latter was on a trip to Washington). Sometimes hands, or in rare cases, the back of heads would also be seen.
Later, personal symbols reflecting some aspect of their character came into use. These included:
The long career of the series and continual use of real-life political figures, analysts note, have led to some uncanny cases of the cartoon foreshadowing a national shift in the politicians' political fortunes. Tina Gianoulis in St. James Encyclopedia of Popular Culture observes that "In 1971, well before the conservative Reagan years, a forward-looking B.D. called Ronald Reagan his 'hero'. In 1984, almost ten years before Congressman Newt Gingrich became Speaker of the House, another character worried that he would 'wake up someday in a country run by Newt Gingrich.'" In its 2003 series "John Kerry: A Candidate in the Making" on the 2004 presidential race, The Boston Globe reprinted and discussed 1971 Doonesbury cartoons of the young Kerry's Vietnam War protest speeches.
Doonesbury has a large group of recurring characters, with 24 currently listed at the strip's website. There, it notes that "readers new to Doonesbury sometimes experience a temporary bout of character shock", as the sheer number of characters (and the historical connections among them) can be overwhelming.
The main characters are a group who attended the fictional Walden College during the strip's first 12 years, and moved into a commune together in April 1972. Most of the other characters first appeared as family members, friends, or other acquaintances. The original Walden Commune residents were Mike Doonesbury, Zonker Harris, Mark Slackmeyer, Nichole, Bernie, and DiDi. In September 1972, Joanie Caucus joined the comic, meeting Mike and Mark in Colorado and eventually moving into the commune. They were later joined by B.D. and his girlfriend (later wife) Boopsie, upon B.D.'s return from Vietnam. Nichole, DiDi, and Bernie were mostly phased out in subsequent years, and Zonker's Uncle Duke was introduced as the most prominent character outside the Walden group, and the main link to many secondary characters.
The Walden students graduated in 1983, after which the strip began to progress in something closer to real time. Their spouses and developing families became more important after this: Joanie's daughter J.J. Caucus married Mike and they had a daughter, Alex Doonesbury. They divorced, Mike married Kim Rosenthal, a Vietnamese refugee (who had appeared in the strip as a baby adopted by a Jewish family just after the fall of Saigon; see Operation Babylift), and J.J. married Zeke Brenner, her former boyfriend and Uncle Duke's former groundskeeper. Joanie married Rick Redfern, and they had a son, Jeff. Uncle Duke and Roland Hedley have also appeared often, frequently in more topical settings unconnected to the main characters. In more recent years the second generation has taken prominence as they have grown to college age: Jeff Redfern, Alex Doonesbury, Zonker's nephew Zipper Harris, and Uncle Duke's son Earl.
Doonesbury has covered numerous political and social issues, some of which were pioneering and others that drew criticism:
Charles M. Schulz of Peanuts called Trudeau "unprofessional" for taking a long sabbatical. (See also, similar comments by Schulz about sabbaticals taken by Bill Watterson.) Nor was the return of the strip itself greeted with universal acclaim; in 1985, Saturday Review listed Trudeau as one of the country's "Most Overrated People in American Arts and Letters", commenting that the "most publicized return since MacArthur's has produced a strip that is predictable, mean-spirited, and not as funny as before."
Doonesbury has angered, irritated, or been rebuked by many of the political figures that have appeared or been referred to in the strip over the years. A 1984 series of strips showing Vice President George H. W. Bush placing his manhood in a blind trust—in parody of Bush's use of that financial instrument to fend off concerns that his governmental decisions would be influenced by his investment holdings—brought the politician to complain, "Doonesbury's carrying water for the opposition. Trudeau is coming out of deep left field."
Some conservatives have intensely criticized Doonesbury. Several examples are cited in the Milestones section of the strip's website. The strip has also met criticism from its readers almost since it began syndicated publication. For example, when Lacey Davenport's husband Dick, in the last moments before his death, calls on God, several conservative pundits called the strip blasphemous. The sequence of Dick Davenport's final bird-watching and fatal heart attack was run in November 1986.
Liberal politicians skewered by Trudeau in the strip have also complained, including Democrats such as former U.S. House Speaker Tip O'Neill and California Governor Jerry Brown.
Strips about post-World War II American wars have also generated controversy, including Vietnam, Grenada, Panama and both Gulf Wars.
After many letter-writing campaigns demanding the removal of the strip were unsuccessful, conservatives changed their tactics, and instead of writing to newspaper editors, they began writing to one of the printers who prints the color Sunday comics. In 2005, Continental Features refused to continue printing the Sunday Doonesbury, causing it to disappear from the 38 Sunday papers that Continental Features printed. Of the 38, only one newspaper, The Anniston Star in Anniston, Alabama, continued to carry the Sunday Doonesbury, though of necessity in black and white.
Some newspapers have dealt with the criticism by moving the strip from the comics page to the editorial page, because many people believe that a politically based comic strip like Doonesbury does not belong in a traditionally child-friendly comics section. The Lincoln Journal started the trend in 1973. In some papers (such as the Tulsa World and Orlando Sentinel) Doonesbury appears on the opinions page alongside Mallard Fillmore, a politically conservative comic strip. | [
{
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"text": "Doonesbury is a comic strip by American cartoonist Garry Trudeau that chronicles the adventures and lives of an array of characters of various ages, professions, and backgrounds, from the President of the United States to the title character, Michael Doonesbury, who has progressed from a college student to a youthful senior citizen over the decades.",
"title": ""
},
{
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"text": "Created in \"the throes of '60s and '70s counterculture\", and frequently political in nature, Doonesbury features characters representing a range of affiliations, but the cartoon is noted for a liberal viewpoint. The name \"Doonesbury\" is a combination of the word doone (American prep school slang for someone who is clueless, inattentive, or careless) and the surname of Charles Pillsbury, Trudeau's roommate at Yale University.",
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{
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"text": "Doonesbury is written and penciled by Garry Trudeau, then inked and lettered by an assistant, Don Carlton, then Todd Pound. Sunday strips are colored by George Corsillo. Doonesbury was a daily strip through most of its existence, but since February 2014 it has run repeat strips Monday through Saturday, and new strips on Sunday.",
"title": ""
},
{
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"text": "Doonesbury began as a continuation of Bull Tales, which appeared in the Yale University student newspaper, the Yale Daily News, from 1968 to 1970. It focused on local campus events at Yale.",
"title": "History"
},
{
"paragraph_id": 4,
"text": "Doonesbury proper debuted as a daily strip in twenty-eight newspapers on October 26, 1970 (it being the first strip from Universal Press Syndicate). A Sunday strip began on March 21, 1971. Many of the early strips were reprints of the Bull Tales cartoons, with some changes to the drawings and plots. B. D.'s helmet changed from having a \"Y\" (for Yale) to a star (for the fictional Walden College). Mike and B. D. started Doonesbury as roommates; they were not roommates in Bull Tales.",
"title": "History"
},
{
"paragraph_id": 5,
"text": "Doonesbury became known for its social and political commentary. By the 2010s, it was syndicated in approximately 1,400 newspapers worldwide.",
"title": "History"
},
{
"paragraph_id": 6,
"text": "In May 1975, Doonesbury became the first daily comic strip to win a Pulitzer Prize, taking the award for Editorial Cartooning. That year, U.S. President Gerald Ford told the Radio and Television Correspondents' Association at their annual dinner, \"There are only three major vehicles to keep us informed as to what is going on in Washington: the electronic media, the print media, and Doonesbury, not necessarily in that order.\"",
"title": "History"
},
{
"paragraph_id": 7,
"text": "Trudeau took a 22-month hiatus, from January 2, 1983, to September 30, 1984. Before the break in the strip, the characters were eternal college students, living in a commune together near Walden College, which was modeled after Trudeau's alma mater, Yale. During the break, Trudeau helped create a Broadway musical of the strip, showing the graduation of the main characters. The Broadway adaptation opened at the Biltmore Theatre on November 21, 1983, and played 104 performances. Elizabeth Swados composed the music for Trudeau's book and lyrics.",
"title": "History"
},
{
"paragraph_id": 8,
"text": "The strip resumed some time after the events in the musical, with further changes having taken place after the end of the musical's plot. Mike, Mark, Zonker, B.D., and Boopsie were all now graduates; B.D. and Boopsie were living in Malibu, California, where B.D. was a third-string quarterback for the Los Angeles Rams, and Boopsie was making a living from walk-on and cameo roles. Mark was living in Washington, D.C., working for National Public Radio. Michael and J.J. had gotten married, and Mike had dropped out of business school to start work in an advertising agency in New York City. Zonker, still not ready for the \"real world\", was living with Mike and J.J. until he was accepted as a medical student at his Uncle Duke's \"Baby Doc College\" in Haiti.",
"title": "History"
},
{
"paragraph_id": 9,
"text": "Prior to the hiatus, the strip's characters had aged only slightly. But when Trudeau returned to Doonesbury, the characters began to age in something close to real time, as in Gasoline Alley and For Better or for Worse, Since then, the main characters' ages and career developments have tracked that of standard media portrayals of baby boomers, with jobs in advertising, law enforcement, and the dot-com boom. Current events are mirrored through the original characters, their offspring (the \"second generation\"), and occasional new characters.",
"title": "History"
},
{
"paragraph_id": 10,
"text": "Garry Trudeau received the National Cartoonist Society Newspaper Comic Strip Award for 1994, and their Reuben Award for 1995 for his work on the strip.",
"title": "History"
},
{
"paragraph_id": 11,
"text": "Doonesbury's syndicate, Universal Uclick, announced on May 29, 2013, that the comic strip would go on hiatus from June 10 to Labor Day of that year while Garry Trudeau worked on his streaming video comedy Alpha House, which was picked up by Amazon Studios. \"Doonesbury Flashbacks\" were offered during those weeks, but due to the unusually long hiatus, some newspapers opted to run different comic strips instead. Sunday strips returned as scheduled, but the daily strip's hiatus was extended until November 2013.",
"title": "History"
},
{
"paragraph_id": 12,
"text": "After Alpha House was renewed for a second season in February 2014, Trudeau announced that he would now produce only Sunday strips for the foreseeable future. Since March 3, 2014, the strip has offered reruns starting from the very beginning of its history as opposed to the recent ones that re-run when Trudeau is on vacation. Alpha House was cancelled in 2016, but Trudeau did not return to drawing Monday-to-Saturday strips, and continued his Sunday-only schedule.",
"title": "History"
},
{
"paragraph_id": 13,
"text": "In a 2018 interview with Rolling Stone, Trudeau said that while Donald Trump appears in only a limited number of strips, \"for the last two years, he's been subtext in almost all of them.\"",
"title": "History"
},
{
"paragraph_id": 14,
"text": "In 1977, Trudeau wrote a script for a 26-minute animated special, A Doonesbury Special, which was produced and directed by Trudeau along with John Hubley (who died during the storyboarding stage) and Faith Hubley. The special was first broadcast by NBC on November 27, 1977. It won a Special Jury Award at the Cannes International Film Festival for best short film, and received an Oscar nomination (for best animated short film), both in 1978. Voice actors for the special included Barbara Harris, William Sloane Coffin, Jr., Jack Gilford and Will Jordan. Also included were \"Stop in the Middle\" and \"I Do Believe\", two songs \"sung\" by the character Jimmy Thudpucker (actually actor/singer/songwriter/producer James Allen \"Jimmy\" Brewer), also part of the \"Special\". While the compositions and performances were credited to \"Jimmy Thudpucker\", they were in fact co-written and sung by Brewer, who also co-wrote and provided the vocals for \"Ginny's Song\", a 1976 single on the Warner Bros. label, and Jimmy Thudpucker's Greatest Hits, an LP released by Windsong Records, John Denver's subsidiary of RCA Records.",
"title": "History"
},
{
"paragraph_id": 15,
"text": "With the exception of Walden College, Trudeau has frequently used real-life settings, based on real scenarios, but with fictional results. Because of lead times, real-world events have rendered some of Trudeau's comics unusable, such as a 1973 series featuring John Ehrlichman, a 1989 series set in Tiananmen Square in Beijing, China, a 1993 series involving Zoë Baird, and a 2005 series involving Harriet Miers. Trudeau has also displayed fluency in various forms of jargon, including those of real estate agents, flight attendants, computer scientists, journalists, presidential aides, and soldiers in Iraq.",
"title": "Style"
},
{
"paragraph_id": 16,
"text": "The unnamed college attended by the main characters was later given the name \"Walden College\", revealed to be in Connecticut (the same state as Yale), and depicted as devolving into a third-rate institution under the weight of grade inflation, slipping academic standards, and the end of tenure, issues that Trudeau has consistently revisited since the original characters graduated. Some of the second generation of Doonesbury characters have attended Walden, a venue Trudeau uses to advance his concerns about academic standards in the United States.",
"title": "Style"
},
{
"paragraph_id": 17,
"text": "President King, the leader of Walden College, was originally intended as a parody of Kingman Brewster, President of Yale, but all that remains of that is a certain physical resemblance.",
"title": "Style"
},
{
"paragraph_id": 18,
"text": "Even though Doonesbury frequently features real-life U.S. politicians, they are rarely depicted with their real faces. Originally, strips featuring the President of the United States would show an external view of the White House, with dialogue emerging from inside. During the Gerald Ford administration, characters would be shown speaking to Ford at press conferences, and fictional dialogue supposedly spoken by Ford would be written as coming \"off-panel\". Similarly, while having several characters as students in a class taught by Henry Kissinger, the dialogue made up for Kissinger would also come from \"off-panel\" (although Kissinger had earlier appeared as a character with his face shown in a 1972 series of strips in which he met Mark Slackmeyer while the latter was on a trip to Washington). Sometimes hands, or in rare cases, the back of heads would also be seen.",
"title": "Style"
},
{
"paragraph_id": 19,
"text": "Later, personal symbols reflecting some aspect of their character came into use. These included:",
"title": "Style"
},
{
"paragraph_id": 20,
"text": "The long career of the series and continual use of real-life political figures, analysts note, have led to some uncanny cases of the cartoon foreshadowing a national shift in the politicians' political fortunes. Tina Gianoulis in St. James Encyclopedia of Popular Culture observes that \"In 1971, well before the conservative Reagan years, a forward-looking B.D. called Ronald Reagan his 'hero'. In 1984, almost ten years before Congressman Newt Gingrich became Speaker of the House, another character worried that he would 'wake up someday in a country run by Newt Gingrich.'\" In its 2003 series \"John Kerry: A Candidate in the Making\" on the 2004 presidential race, The Boston Globe reprinted and discussed 1971 Doonesbury cartoons of the young Kerry's Vietnam War protest speeches.",
"title": "Style"
},
{
"paragraph_id": 21,
"text": "Doonesbury has a large group of recurring characters, with 24 currently listed at the strip's website. There, it notes that \"readers new to Doonesbury sometimes experience a temporary bout of character shock\", as the sheer number of characters (and the historical connections among them) can be overwhelming.",
"title": "Characters"
},
{
"paragraph_id": 22,
"text": "The main characters are a group who attended the fictional Walden College during the strip's first 12 years, and moved into a commune together in April 1972. Most of the other characters first appeared as family members, friends, or other acquaintances. The original Walden Commune residents were Mike Doonesbury, Zonker Harris, Mark Slackmeyer, Nichole, Bernie, and DiDi. In September 1972, Joanie Caucus joined the comic, meeting Mike and Mark in Colorado and eventually moving into the commune. They were later joined by B.D. and his girlfriend (later wife) Boopsie, upon B.D.'s return from Vietnam. Nichole, DiDi, and Bernie were mostly phased out in subsequent years, and Zonker's Uncle Duke was introduced as the most prominent character outside the Walden group, and the main link to many secondary characters.",
"title": "Characters"
},
{
"paragraph_id": 23,
"text": "The Walden students graduated in 1983, after which the strip began to progress in something closer to real time. Their spouses and developing families became more important after this: Joanie's daughter J.J. Caucus married Mike and they had a daughter, Alex Doonesbury. They divorced, Mike married Kim Rosenthal, a Vietnamese refugee (who had appeared in the strip as a baby adopted by a Jewish family just after the fall of Saigon; see Operation Babylift), and J.J. married Zeke Brenner, her former boyfriend and Uncle Duke's former groundskeeper. Joanie married Rick Redfern, and they had a son, Jeff. Uncle Duke and Roland Hedley have also appeared often, frequently in more topical settings unconnected to the main characters. In more recent years the second generation has taken prominence as they have grown to college age: Jeff Redfern, Alex Doonesbury, Zonker's nephew Zipper Harris, and Uncle Duke's son Earl.",
"title": "Characters"
},
{
"paragraph_id": 24,
"text": "Doonesbury has covered numerous political and social issues, some of which were pioneering and others that drew criticism:",
"title": "Controversial strips and groundbreaking moments"
},
{
"paragraph_id": 25,
"text": "Charles M. Schulz of Peanuts called Trudeau \"unprofessional\" for taking a long sabbatical. (See also, similar comments by Schulz about sabbaticals taken by Bill Watterson.) Nor was the return of the strip itself greeted with universal acclaim; in 1985, Saturday Review listed Trudeau as one of the country's \"Most Overrated People in American Arts and Letters\", commenting that the \"most publicized return since MacArthur's has produced a strip that is predictable, mean-spirited, and not as funny as before.\"",
"title": "Criticism"
},
{
"paragraph_id": 26,
"text": "Doonesbury has angered, irritated, or been rebuked by many of the political figures that have appeared or been referred to in the strip over the years. A 1984 series of strips showing Vice President George H. W. Bush placing his manhood in a blind trust—in parody of Bush's use of that financial instrument to fend off concerns that his governmental decisions would be influenced by his investment holdings—brought the politician to complain, \"Doonesbury's carrying water for the opposition. Trudeau is coming out of deep left field.\"",
"title": "Criticism"
},
{
"paragraph_id": 27,
"text": "Some conservatives have intensely criticized Doonesbury. Several examples are cited in the Milestones section of the strip's website. The strip has also met criticism from its readers almost since it began syndicated publication. For example, when Lacey Davenport's husband Dick, in the last moments before his death, calls on God, several conservative pundits called the strip blasphemous. The sequence of Dick Davenport's final bird-watching and fatal heart attack was run in November 1986.",
"title": "Criticism"
},
{
"paragraph_id": 28,
"text": "Liberal politicians skewered by Trudeau in the strip have also complained, including Democrats such as former U.S. House Speaker Tip O'Neill and California Governor Jerry Brown.",
"title": "Criticism"
},
{
"paragraph_id": 29,
"text": "Strips about post-World War II American wars have also generated controversy, including Vietnam, Grenada, Panama and both Gulf Wars.",
"title": "Criticism"
},
{
"paragraph_id": 30,
"text": "After many letter-writing campaigns demanding the removal of the strip were unsuccessful, conservatives changed their tactics, and instead of writing to newspaper editors, they began writing to one of the printers who prints the color Sunday comics. In 2005, Continental Features refused to continue printing the Sunday Doonesbury, causing it to disappear from the 38 Sunday papers that Continental Features printed. Of the 38, only one newspaper, The Anniston Star in Anniston, Alabama, continued to carry the Sunday Doonesbury, though of necessity in black and white.",
"title": "Criticism"
},
{
"paragraph_id": 31,
"text": "Some newspapers have dealt with the criticism by moving the strip from the comics page to the editorial page, because many people believe that a politically based comic strip like Doonesbury does not belong in a traditionally child-friendly comics section. The Lincoln Journal started the trend in 1973. In some papers (such as the Tulsa World and Orlando Sentinel) Doonesbury appears on the opinions page alongside Mallard Fillmore, a politically conservative comic strip.",
"title": "Criticism"
}
] | Doonesbury is a comic strip by American cartoonist Garry Trudeau that chronicles the adventures and lives of an array of characters of various ages, professions, and backgrounds, from the President of the United States to the title character, Michael Doonesbury, who has progressed from a college student to a youthful senior citizen over the decades. Created in "the throes of '60s and '70s counterculture", and frequently political in nature, Doonesbury features characters representing a range of affiliations, but the cartoon is noted for a liberal viewpoint. The name "Doonesbury" is a combination of the word doone and the surname of Charles Pillsbury, Trudeau's roommate at Yale University. Doonesbury is written and penciled by Garry Trudeau, then inked and lettered by an assistant, Don Carlton,
then Todd Pound. Sunday strips are colored by George Corsillo. Doonesbury was a daily strip through most of its existence, but since February 2014 it has run repeat strips Monday through Saturday, and new strips on Sunday. | 2001-07-27T00:26:59Z | 2023-12-01T15:30:17Z | [
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] | https://en.wikipedia.org/wiki/Doonesbury |
8,244 | Dice | Dice (SG: die or dice) are small, throwable objects with marked sides that can rest in multiple positions. They are used for generating random values, commonly as part of tabletop games, including dice games, board games, role-playing games, and games of chance.
A traditional die is a cube with each of its six faces marked with a different number of dots (pips) from one to six. When thrown or rolled, the die comes to rest showing a random integer from one to six on its upper surface, with each value being equally likely. Dice may also have polyhedral or irregular shapes, may have faces marked with numerals or symbols instead of pips and may have their numbers carved out from the material of the dice instead of marked on it. Loaded dice are designed to favor some results over others for cheating or entertainment.
Dice have been used since before recorded history, and it is uncertain where they originated. It is theorized that dice developed from the practice of fortune-telling with the talus of hoofed animals, colloquially known as knucklebones. The Egyptian game of senet (played before 3000 BCE and up to the 2nd century CE) was played with flat two-sided throwsticks which indicated the number of squares a player could move, and thus functioned as a form of dice. Perhaps the oldest known dice were excavated as part of a backgammon-like game set at the Burnt City, an archeological site in south-eastern Iran, estimated to be from between 2800 and 2500 BCE. Bone dice from Skara Brae, Scotland have been dated to 3100–2400 BCE. Excavations from graves at Mohenjo-daro, an Indus Valley civilization settlement, unearthed terracotta dice dating to 2500–1900 BCE, including at least one die whose opposite sides all add up to seven, as in modern dice.
Games involving dice are mentioned in the ancient Indian Rigveda, Atharvaveda, Mahabharata and Buddhist games list. There are several biblical references to "casting lots" (Hebrew: יפילו גורל yappîlū ḡōrāl), as in Psalm 22, indicating that dicing (or a related activity) was commonplace when the psalm was composed. Knucklebones was a game of skill played in ancient Greece; a derivative form had the four sides of bones receive different values like modern dice.
Although gambling was illegal, many Romans were passionate gamblers who enjoyed dicing, which was known as aleam ludere ("to play at dice"). There were two sizes of Roman dice. Tali were large dice inscribed with one, three, four, and six on four sides. Tesserae were smaller dice with sides numbered from one to six. Twenty-sided dice date back to the 2nd century CE and from Ptolemaic Egypt as early as the 2nd century BCE.
Dominoes and playing cards originated in China as developments from dice. The transition from dice to playing cards occurred in China around the Tang dynasty (618–907 CE), and coincides with the technological transition from rolls of manuscripts to block printed books. In Japan, dice were used to play a popular game called sugoroku. There are two types of sugoroku. Ban-sugoroku is similar to backgammon and dates to the Heian period (794–1185 CE), while e-sugoroku is a racing game.
Dice are thrown onto a surface either from the hand or from a container designed for this (such as a cup, tray, or tower). The face (or corner, in cases such as tetrahedral dice, or edge, for odd-numbered long dice) of the die that is uppermost when it comes to rest provides the value of the throw.
The result of a die roll is determined by the way it is thrown, according to the laws of classical mechanics (although luck is often credited for the results of a roll). A die roll is made random by uncertainty in minor factors such as tiny movements in the thrower's hand; they are thus a crude form of hardware random number generator.
One typical contemporary dice game is craps, where two dice are thrown simultaneously and wagers are made on the total value of the two dice. Dice are frequently used to introduce randomness into board games, where they are often used to decide the distance through which a piece will move along the board (as in backgammon and Monopoly).
Common dice are small cubes, most often 1.6 cm (0.63 in) across, whose faces are numbered from one to six, usually by patterns of round dots called pips. (While the use of Arabic numerals is occasionally seen, such dice are less common.)
Opposite sides of a modern die traditionally add up to seven, requiring the 1, 2, and 3 faces to share a vertex. The faces of a die may be placed clockwise or counterclockwise about this vertex. If the 1, 2, and 3 faces run counterclockwise, the die is called "right-handed". If those faces run clockwise, the die is called "left-handed". Western dice are normally right-handed, and Chinese dice are normally left-handed.
The pips on standard six-sided dice are arranged in specific patterns as shown. Asian style dice bear similar patterns to Western ones, but the pips are closer to the center of the face; in addition, the pips are differently sized on Asian style dice, and the pips are colored red on the 1 and 4 sides. Red fours may be of Indian origin.
Non-precision dice are manufactured via the plastic injection molding process, often made of polymethyl methacrylate (PMMA). The pips or numbers on the die are a part of the mold. Different pigments can be added to the dice to make them opaque or transparent, or multiple pigments may be added to make the dice speckled or marbled.
The coloring for numbering is achieved by submerging the die entirely in paint, which is allowed to dry. The die is then polished via a tumble finishing process similar to rock polishing. The abrasive agent scrapes off all of the paint except for the indents of the numbering. A finer abrasive is then used to polish the die. This process also produces the smoother, rounded edges on the dice.
Precision casino dice may have a polished or sand finish, making them transparent or translucent respectively. Casino dice have their pips drilled, then filled flush with a paint of the same density as the material used for the dice, such that the center of gravity of the dice is as close to the geometric center as possible. This mitigates concerns that the pips will cause a small bias. All such dice are stamped with a serial number to prevent potential cheaters from substituting a die. Precision backgammon dice are made the same way; they tend to be slightly smaller and have rounded corners and edges, to allow better movement inside the dice cup and stop forceful rolls from damaging the playing surface.
The word die comes from Old French dé; from Latin datum "something which is given or played".
While the terms ace, deuce, trey, cater, cinque and sice are generally obsolete, with the names of the numbers preferred, they are still used by some professional gamblers to designate different sides of the dice. Ace is from the Latin as, meaning "a unit"; the others are 2 to 6 in Old French.
When rolling two dice, certain combinations have slang names. The term snake eyes is a roll of one pip on each die. The Online Etymology Dictionary traces use of the term as far back as 1919. The US term boxcars, also known as midnight, is a roll of six pips on each die. The pair of six pips resembles a pair of boxcars on a freight train. Many rolls have names in the game of craps.
⚀ ⚁ ⚂ ⚃ ⚄ ⚅ 🎲
Using Unicode characters, the faces can be shown in text using the range U+2680 to U+2685 or using decimal ⚀ to ⚅, and the emoji using U+1F3B2 or 🎲 from the Miscellaneous Symbols and Pictographs block.
A loaded, weighted, cheat, or crooked die is one that has been tampered with so that it will land with a specific side facing upwards more or less often than a fair die would. There are several methods for making loaded dice, including rounded faces, off-square faces, and weights. Casinos and gambling halls frequently use transparent cellulose acetate dice as tampering is easier to detect than with opaque dice.
Various shapes like two-sided or four-sided dice are documented in archaeological findings; for example, from Ancient Egypt and the Middle East. While the cubical six-sided die became the most common type in many parts of the world, other shapes were always known, like 20-sided dice in Ptolemaic and Roman times.
The modern tradition of using sets of polyhedral dice started around the end of the 1960s when non-cubical dice became popular among players of wargames, and since have been employed extensively in role-playing games and trading card games. Dice using both the numerals 6 and 9, which are reciprocally symmetric through rotation, typically distinguish them with a dot or underline.
Dice are often sold in sets, matching in color, of six different shapes. Five of the dice are shaped like the Platonic solids, whose faces are regular polygons. Aside from the cube, the other four Platonic solids have 4, 8, 12, and 20 faces, allowing for those number ranges to be generated. The only other common non-cubical die is the 10-sided die, a pentagonal trapezohedron die, whose faces are ten kites, each with two different edge lengths, three different angles, and two different kinds of vertices. Such sets frequently include a second 10-sided die either of contrasting color or numbered by tens, allowing the pair of 10-sided dice to be combined to generate numbers between 1 and 100.
Using these dice in various ways, games can closely approximate a variety of probability distributions. For instance, 10-sided dice can be rolled in pairs to produce a uniform distribution of random percentages, and summing the values of multiple dice will produce approximations to normal distributions.
Unlike other common dice, a four-sided (tetrahedral) die does not have a side that faces upward when it is at rest on a surface, so it must be read in a different way. On some four-sided dice, each face features multiple numbers, with the same number printed near each vertex on all sides. In this case, the number around the vertex pointing up is used. Alternatively, the numbers on a tetrahedral die can be placed at the middles of the edges, in which case the numbers around the base are used.
Normally, the faces on a die will be placed so opposite faces will add up to one more than the number of faces. (This is not possible with 4-sided dice and dice with an odd number of faces.) Some dice, such as those with 10 sides, are usually numbered sequentially beginning with 0, in which case the opposite faces will add to one less than the number of faces.
Some twenty-sided dice have a different arrangement used for the purpose of keeping track of an integer that counts down, such as health points. These spindown dice are arranged such that adjacent integers appear on adjacent faces, allowing the user to easily find the next lower number. They are commonly used with collectible card games.
"Uniform fair dice" are dice where all faces have equal probability of outcome due to the symmetry of the die as it is face-transitive. In addition to the Platonic solids, these theoretically include:
Two other types of polyhedra are technically not face-transitive, but are still fair dice due to symmetry:
Long dice and teetotums can in principle be made with any number of faces, including odd numbers. Long dice are based on the infinite set of prisms. All the rectangular faces are mutually face-transitive, so they are equally probable. The two ends of the prism may be rounded or capped with a pyramid, designed so that the die cannot rest on those faces. 4-sided long dice are easier to roll than tetrahedra, and are used in the traditional board games dayakattai and daldøs.
The faces of most dice are labelled using sequences of whole numbers, usually starting at one, expressed with either pips or digits. However, there are some applications that require results other than numbers. Examples include letters for Boggle, directions for Warhammer Fantasy Battle, Fudge dice, playing card symbols for poker dice, and instructions for sexual acts using sex dice.
Dice may have numbers that do not form a counting sequence starting at one. One variation on the standard die is known as the "average" die. These are six-sided dice with sides numbered 2, 3, 3, 4, 4, 5, which have the same arithmetic mean as a standard die (3.5 for a single die, 7 for a pair of dice), but have a narrower range of possible values (2 through 5 for one, 4 through 10 for a pair). They are used in some table-top wargames, where a narrower range of numbers is required. Other numbered variations include Sicherman dice and intransitive dice.
A die can be constructed in the shape of a sphere, with the addition of an internal cavity in the shape of the dual polyhedron of the desired die shape and an internal weight. The weight will settle in one of the points of the internal cavity, causing it to settle with one of the numbers uppermost. For instance, a sphere with an octahedral cavity and a small internal weight will settle with one of the 6 points of the cavity held downwards by the weight.
Many board games use dice to randomize how far pieces move or to settle conflicts. Typically, this has meant that rolling higher numbers is better. Some games, such as Axis & Allies, have inverted this system by making the lower values more potent. In the modern age, a few games and game designers have approached dice in a different way by making each side of the die similarly valuable. In Castles of Burgundy, players spend their dice to take actions based on the die's value. In this game, a six is not better than a one, or vice versa. In Quarriors (and its descendant, Dicemasters), different sides of the dice can offer completely different abilities. Several sides often give resources while others grant the player useful actions.
Dice can be used for divination and using dice for such a purpose is called cleromancy. A pair of common dice is usual, though other forms of polyhedra can be used. Tibetan Buddhists sometimes use this method of divination. It is highly likely that the Pythagoreans used the Platonic solids as dice. They referred to such dice as "the dice of the gods" and they sought to understand the universe through an understanding of geometry in polyhedra.
Polyhedral dice are commonly used in role-playing games. The fantasy role-playing game Dungeons & Dragons (D&D) is largely credited with popularizing dice in such games. Some games use only one type, like Exalted which uses only ten-sided dice. Others use numerous types for different game purposes, such as D&D, which makes use of all common polyhedral dice. Dice are usually used to determine the outcome of events. Games typically determine results either as a total on one or more dice above or below a fixed number, or a certain number of rolls above a certain number on one or more dice. Due to circumstances or character skill, the initial roll may have a number added to or subtracted from the final result, or have the player roll extra or fewer dice. To keep track of rolls easily, dice notation is frequently used.
Astrological dice are a specialized set of three 12-sided dice for divination; the first die represents the planets, the Sun, the Moon, and the nodes of the Moon, the second die represents the 12 zodiac signs, and the third represents the 12 houses. A specialized icosahedron die provides the answers of the Magic 8 Ball, conventionally used to provide answers to yes-or-no questions.
Dice can be used to generate random numbers for use in passwords and cryptography applications. The Electronic Frontier Foundation describes a method by which dice can be used to generate passphrases. Diceware is a method recommended for generating secure but memorable passphrases, by repeatedly rolling five dice and picking the corresponding word from a pre-generated list.
In many gaming contexts, especially tabletop role-playing games, shorthand notations representing different dice rolls are used. A "d" or "D" is used to indicate a die with a specific number of sides; for example,d4denotes a four-sided die. If several dice of the same type are to be rolled, this is indicated by a leading number specifying the number of dice. Hence,6d8 means the player should roll six eight-sided dice and add the results. Modifiers to a die roll can also be indicated as desired. For example, 3d6+4 instructs the player to roll three six-sided dice, calculate the total, and add four to it.
This article incorporates text from a publication now in the public domain: Chisholm, Hugh, ed. (1911). "Dice". Encyclopædia Britannica. Vol. 8 (11th ed.). Cambridge University Press. p. 176–177. | [
{
"paragraph_id": 0,
"text": "Dice (SG: die or dice) are small, throwable objects with marked sides that can rest in multiple positions. They are used for generating random values, commonly as part of tabletop games, including dice games, board games, role-playing games, and games of chance.",
"title": ""
},
{
"paragraph_id": 1,
"text": "A traditional die is a cube with each of its six faces marked with a different number of dots (pips) from one to six. When thrown or rolled, the die comes to rest showing a random integer from one to six on its upper surface, with each value being equally likely. Dice may also have polyhedral or irregular shapes, may have faces marked with numerals or symbols instead of pips and may have their numbers carved out from the material of the dice instead of marked on it. Loaded dice are designed to favor some results over others for cheating or entertainment.",
"title": ""
},
{
"paragraph_id": 2,
"text": "Dice have been used since before recorded history, and it is uncertain where they originated. It is theorized that dice developed from the practice of fortune-telling with the talus of hoofed animals, colloquially known as knucklebones. The Egyptian game of senet (played before 3000 BCE and up to the 2nd century CE) was played with flat two-sided throwsticks which indicated the number of squares a player could move, and thus functioned as a form of dice. Perhaps the oldest known dice were excavated as part of a backgammon-like game set at the Burnt City, an archeological site in south-eastern Iran, estimated to be from between 2800 and 2500 BCE. Bone dice from Skara Brae, Scotland have been dated to 3100–2400 BCE. Excavations from graves at Mohenjo-daro, an Indus Valley civilization settlement, unearthed terracotta dice dating to 2500–1900 BCE, including at least one die whose opposite sides all add up to seven, as in modern dice.",
"title": "History"
},
{
"paragraph_id": 3,
"text": "Games involving dice are mentioned in the ancient Indian Rigveda, Atharvaveda, Mahabharata and Buddhist games list. There are several biblical references to \"casting lots\" (Hebrew: יפילו גורל yappîlū ḡōrāl), as in Psalm 22, indicating that dicing (or a related activity) was commonplace when the psalm was composed. Knucklebones was a game of skill played in ancient Greece; a derivative form had the four sides of bones receive different values like modern dice.",
"title": "History"
},
{
"paragraph_id": 4,
"text": "Although gambling was illegal, many Romans were passionate gamblers who enjoyed dicing, which was known as aleam ludere (\"to play at dice\"). There were two sizes of Roman dice. Tali were large dice inscribed with one, three, four, and six on four sides. Tesserae were smaller dice with sides numbered from one to six. Twenty-sided dice date back to the 2nd century CE and from Ptolemaic Egypt as early as the 2nd century BCE.",
"title": "History"
},
{
"paragraph_id": 5,
"text": "Dominoes and playing cards originated in China as developments from dice. The transition from dice to playing cards occurred in China around the Tang dynasty (618–907 CE), and coincides with the technological transition from rolls of manuscripts to block printed books. In Japan, dice were used to play a popular game called sugoroku. There are two types of sugoroku. Ban-sugoroku is similar to backgammon and dates to the Heian period (794–1185 CE), while e-sugoroku is a racing game.",
"title": "History"
},
{
"paragraph_id": 6,
"text": "Dice are thrown onto a surface either from the hand or from a container designed for this (such as a cup, tray, or tower). The face (or corner, in cases such as tetrahedral dice, or edge, for odd-numbered long dice) of the die that is uppermost when it comes to rest provides the value of the throw.",
"title": "Use"
},
{
"paragraph_id": 7,
"text": "The result of a die roll is determined by the way it is thrown, according to the laws of classical mechanics (although luck is often credited for the results of a roll). A die roll is made random by uncertainty in minor factors such as tiny movements in the thrower's hand; they are thus a crude form of hardware random number generator.",
"title": "Use"
},
{
"paragraph_id": 8,
"text": "One typical contemporary dice game is craps, where two dice are thrown simultaneously and wagers are made on the total value of the two dice. Dice are frequently used to introduce randomness into board games, where they are often used to decide the distance through which a piece will move along the board (as in backgammon and Monopoly).",
"title": "Use"
},
{
"paragraph_id": 9,
"text": "Common dice are small cubes, most often 1.6 cm (0.63 in) across, whose faces are numbered from one to six, usually by patterns of round dots called pips. (While the use of Arabic numerals is occasionally seen, such dice are less common.)",
"title": "Construction"
},
{
"paragraph_id": 10,
"text": "Opposite sides of a modern die traditionally add up to seven, requiring the 1, 2, and 3 faces to share a vertex. The faces of a die may be placed clockwise or counterclockwise about this vertex. If the 1, 2, and 3 faces run counterclockwise, the die is called \"right-handed\". If those faces run clockwise, the die is called \"left-handed\". Western dice are normally right-handed, and Chinese dice are normally left-handed.",
"title": "Construction"
},
{
"paragraph_id": 11,
"text": "The pips on standard six-sided dice are arranged in specific patterns as shown. Asian style dice bear similar patterns to Western ones, but the pips are closer to the center of the face; in addition, the pips are differently sized on Asian style dice, and the pips are colored red on the 1 and 4 sides. Red fours may be of Indian origin.",
"title": "Construction"
},
{
"paragraph_id": 12,
"text": "Non-precision dice are manufactured via the plastic injection molding process, often made of polymethyl methacrylate (PMMA). The pips or numbers on the die are a part of the mold. Different pigments can be added to the dice to make them opaque or transparent, or multiple pigments may be added to make the dice speckled or marbled.",
"title": "Construction"
},
{
"paragraph_id": 13,
"text": "The coloring for numbering is achieved by submerging the die entirely in paint, which is allowed to dry. The die is then polished via a tumble finishing process similar to rock polishing. The abrasive agent scrapes off all of the paint except for the indents of the numbering. A finer abrasive is then used to polish the die. This process also produces the smoother, rounded edges on the dice.",
"title": "Construction"
},
{
"paragraph_id": 14,
"text": "Precision casino dice may have a polished or sand finish, making them transparent or translucent respectively. Casino dice have their pips drilled, then filled flush with a paint of the same density as the material used for the dice, such that the center of gravity of the dice is as close to the geometric center as possible. This mitigates concerns that the pips will cause a small bias. All such dice are stamped with a serial number to prevent potential cheaters from substituting a die. Precision backgammon dice are made the same way; they tend to be slightly smaller and have rounded corners and edges, to allow better movement inside the dice cup and stop forceful rolls from damaging the playing surface.",
"title": "Construction"
},
{
"paragraph_id": 15,
"text": "The word die comes from Old French dé; from Latin datum \"something which is given or played\".",
"title": "Construction"
},
{
"paragraph_id": 16,
"text": "While the terms ace, deuce, trey, cater, cinque and sice are generally obsolete, with the names of the numbers preferred, they are still used by some professional gamblers to designate different sides of the dice. Ace is from the Latin as, meaning \"a unit\"; the others are 2 to 6 in Old French.",
"title": "Construction"
},
{
"paragraph_id": 17,
"text": "When rolling two dice, certain combinations have slang names. The term snake eyes is a roll of one pip on each die. The Online Etymology Dictionary traces use of the term as far back as 1919. The US term boxcars, also known as midnight, is a roll of six pips on each die. The pair of six pips resembles a pair of boxcars on a freight train. Many rolls have names in the game of craps.",
"title": "Construction"
},
{
"paragraph_id": 18,
"text": "⚀ ⚁ ⚂ ⚃ ⚄ ⚅ 🎲",
"title": "Construction"
},
{
"paragraph_id": 19,
"text": "Using Unicode characters, the faces can be shown in text using the range U+2680 to U+2685 or using decimal ⚀ to ⚅, and the emoji using U+1F3B2 or 🎲 from the Miscellaneous Symbols and Pictographs block.",
"title": "Construction"
},
{
"paragraph_id": 20,
"text": "A loaded, weighted, cheat, or crooked die is one that has been tampered with so that it will land with a specific side facing upwards more or less often than a fair die would. There are several methods for making loaded dice, including rounded faces, off-square faces, and weights. Casinos and gambling halls frequently use transparent cellulose acetate dice as tampering is easier to detect than with opaque dice.",
"title": "Loaded dice"
},
{
"paragraph_id": 21,
"text": "Various shapes like two-sided or four-sided dice are documented in archaeological findings; for example, from Ancient Egypt and the Middle East. While the cubical six-sided die became the most common type in many parts of the world, other shapes were always known, like 20-sided dice in Ptolemaic and Roman times.",
"title": "Variants"
},
{
"paragraph_id": 22,
"text": "The modern tradition of using sets of polyhedral dice started around the end of the 1960s when non-cubical dice became popular among players of wargames, and since have been employed extensively in role-playing games and trading card games. Dice using both the numerals 6 and 9, which are reciprocally symmetric through rotation, typically distinguish them with a dot or underline.",
"title": "Variants"
},
{
"paragraph_id": 23,
"text": "Dice are often sold in sets, matching in color, of six different shapes. Five of the dice are shaped like the Platonic solids, whose faces are regular polygons. Aside from the cube, the other four Platonic solids have 4, 8, 12, and 20 faces, allowing for those number ranges to be generated. The only other common non-cubical die is the 10-sided die, a pentagonal trapezohedron die, whose faces are ten kites, each with two different edge lengths, three different angles, and two different kinds of vertices. Such sets frequently include a second 10-sided die either of contrasting color or numbered by tens, allowing the pair of 10-sided dice to be combined to generate numbers between 1 and 100.",
"title": "Variants"
},
{
"paragraph_id": 24,
"text": "Using these dice in various ways, games can closely approximate a variety of probability distributions. For instance, 10-sided dice can be rolled in pairs to produce a uniform distribution of random percentages, and summing the values of multiple dice will produce approximations to normal distributions.",
"title": "Variants"
},
{
"paragraph_id": 25,
"text": "Unlike other common dice, a four-sided (tetrahedral) die does not have a side that faces upward when it is at rest on a surface, so it must be read in a different way. On some four-sided dice, each face features multiple numbers, with the same number printed near each vertex on all sides. In this case, the number around the vertex pointing up is used. Alternatively, the numbers on a tetrahedral die can be placed at the middles of the edges, in which case the numbers around the base are used.",
"title": "Variants"
},
{
"paragraph_id": 26,
"text": "Normally, the faces on a die will be placed so opposite faces will add up to one more than the number of faces. (This is not possible with 4-sided dice and dice with an odd number of faces.) Some dice, such as those with 10 sides, are usually numbered sequentially beginning with 0, in which case the opposite faces will add to one less than the number of faces.",
"title": "Variants"
},
{
"paragraph_id": 27,
"text": "Some twenty-sided dice have a different arrangement used for the purpose of keeping track of an integer that counts down, such as health points. These spindown dice are arranged such that adjacent integers appear on adjacent faces, allowing the user to easily find the next lower number. They are commonly used with collectible card games.",
"title": "Variants"
},
{
"paragraph_id": 28,
"text": "\"Uniform fair dice\" are dice where all faces have equal probability of outcome due to the symmetry of the die as it is face-transitive. In addition to the Platonic solids, these theoretically include:",
"title": "Variants"
},
{
"paragraph_id": 29,
"text": "Two other types of polyhedra are technically not face-transitive, but are still fair dice due to symmetry:",
"title": "Variants"
},
{
"paragraph_id": 30,
"text": "Long dice and teetotums can in principle be made with any number of faces, including odd numbers. Long dice are based on the infinite set of prisms. All the rectangular faces are mutually face-transitive, so they are equally probable. The two ends of the prism may be rounded or capped with a pyramid, designed so that the die cannot rest on those faces. 4-sided long dice are easier to roll than tetrahedra, and are used in the traditional board games dayakattai and daldøs.",
"title": "Variants"
},
{
"paragraph_id": 31,
"text": "The faces of most dice are labelled using sequences of whole numbers, usually starting at one, expressed with either pips or digits. However, there are some applications that require results other than numbers. Examples include letters for Boggle, directions for Warhammer Fantasy Battle, Fudge dice, playing card symbols for poker dice, and instructions for sexual acts using sex dice.",
"title": "Variants"
},
{
"paragraph_id": 32,
"text": "Dice may have numbers that do not form a counting sequence starting at one. One variation on the standard die is known as the \"average\" die. These are six-sided dice with sides numbered 2, 3, 3, 4, 4, 5, which have the same arithmetic mean as a standard die (3.5 for a single die, 7 for a pair of dice), but have a narrower range of possible values (2 through 5 for one, 4 through 10 for a pair). They are used in some table-top wargames, where a narrower range of numbers is required. Other numbered variations include Sicherman dice and intransitive dice.",
"title": "Variants"
},
{
"paragraph_id": 33,
"text": "A die can be constructed in the shape of a sphere, with the addition of an internal cavity in the shape of the dual polyhedron of the desired die shape and an internal weight. The weight will settle in one of the points of the internal cavity, causing it to settle with one of the numbers uppermost. For instance, a sphere with an octahedral cavity and a small internal weight will settle with one of the 6 points of the cavity held downwards by the weight.",
"title": "Variants"
},
{
"paragraph_id": 34,
"text": "Many board games use dice to randomize how far pieces move or to settle conflicts. Typically, this has meant that rolling higher numbers is better. Some games, such as Axis & Allies, have inverted this system by making the lower values more potent. In the modern age, a few games and game designers have approached dice in a different way by making each side of the die similarly valuable. In Castles of Burgundy, players spend their dice to take actions based on the die's value. In this game, a six is not better than a one, or vice versa. In Quarriors (and its descendant, Dicemasters), different sides of the dice can offer completely different abilities. Several sides often give resources while others grant the player useful actions.",
"title": "Applications"
},
{
"paragraph_id": 35,
"text": "Dice can be used for divination and using dice for such a purpose is called cleromancy. A pair of common dice is usual, though other forms of polyhedra can be used. Tibetan Buddhists sometimes use this method of divination. It is highly likely that the Pythagoreans used the Platonic solids as dice. They referred to such dice as \"the dice of the gods\" and they sought to understand the universe through an understanding of geometry in polyhedra.",
"title": "Applications"
},
{
"paragraph_id": 36,
"text": "Polyhedral dice are commonly used in role-playing games. The fantasy role-playing game Dungeons & Dragons (D&D) is largely credited with popularizing dice in such games. Some games use only one type, like Exalted which uses only ten-sided dice. Others use numerous types for different game purposes, such as D&D, which makes use of all common polyhedral dice. Dice are usually used to determine the outcome of events. Games typically determine results either as a total on one or more dice above or below a fixed number, or a certain number of rolls above a certain number on one or more dice. Due to circumstances or character skill, the initial roll may have a number added to or subtracted from the final result, or have the player roll extra or fewer dice. To keep track of rolls easily, dice notation is frequently used.",
"title": "Applications"
},
{
"paragraph_id": 37,
"text": "Astrological dice are a specialized set of three 12-sided dice for divination; the first die represents the planets, the Sun, the Moon, and the nodes of the Moon, the second die represents the 12 zodiac signs, and the third represents the 12 houses. A specialized icosahedron die provides the answers of the Magic 8 Ball, conventionally used to provide answers to yes-or-no questions.",
"title": "Applications"
},
{
"paragraph_id": 38,
"text": "Dice can be used to generate random numbers for use in passwords and cryptography applications. The Electronic Frontier Foundation describes a method by which dice can be used to generate passphrases. Diceware is a method recommended for generating secure but memorable passphrases, by repeatedly rolling five dice and picking the corresponding word from a pre-generated list.",
"title": "Applications"
},
{
"paragraph_id": 39,
"text": "In many gaming contexts, especially tabletop role-playing games, shorthand notations representing different dice rolls are used. A \"d\" or \"D\" is used to indicate a die with a specific number of sides; for example,d4denotes a four-sided die. If several dice of the same type are to be rolled, this is indicated by a leading number specifying the number of dice. Hence,6d8 means the player should roll six eight-sided dice and add the results. Modifiers to a die roll can also be indicated as desired. For example, 3d6+4 instructs the player to roll three six-sided dice, calculate the total, and add four to it.",
"title": "Applications"
},
{
"paragraph_id": 40,
"text": "This article incorporates text from a publication now in the public domain: Chisholm, Hugh, ed. (1911). \"Dice\". Encyclopædia Britannica. Vol. 8 (11th ed.). Cambridge University Press. p. 176–177.",
"title": "External links"
}
] | Dice are small, throwable objects with marked sides that can rest in multiple positions. They are used for generating random values, commonly as part of tabletop games, including dice games, board games, role-playing games, and games of chance. A traditional die is a cube with each of its six faces marked with a different number of dots (pips) from one to six. When thrown or rolled, the die comes to rest showing a random integer from one to six on its upper surface, with each value being equally likely. Dice may also have polyhedral or irregular shapes, may have faces marked with numerals or symbols instead of pips and may have their numbers carved out from the material of the dice instead of marked on it. Loaded dice are designed to favor some results over others for cheating or entertainment. | 2001-07-28T06:41:54Z | 2023-12-25T08:54:41Z | [
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] | https://en.wikipedia.org/wiki/Dice |
8,246 | Dumpster diving | Dumpster diving (also totting, skipping, skip diving or skip salvage) is salvaging from large commercial, residential, industrial and construction containers for unused items discarded by their owners but deemed useful to the picker. It is not confined to dumpsters and skips specifically and may cover standard household waste containers, curb sides, landfills or small dumps.
Different terms are used to refer to different forms of this activity. For picking materials from the curbside trash collection, expressions such as curb shopping, trash picking or street scavenging are sometimes used. In the UK, if someone is primarily seeking recyclable metal, they are scrapping, and if they are picking the leftover food from farming left in the fields, they are gleaning.
People dumpster dive for items such as clothing, furniture, food, and similar items in good working condition. Some people do this out of necessity due to poverty, others do it for ideological reasons or professionally and systematically for profit.
The term "dumpster diving" emerged in the 1980s, combining "diving" with "dumpster", a large commercial trash bin. The term "Dumpster" itself comes from the Dempster Dumpster, a brand of bins manufactured by Dempster Brothers beginning in 1937. "Dumpster" became genericized by the 1970s. According to the Oxford English Dictionary, the term "dumpster diving" is chiefly found in American English and first appeared in print in 1983, with the verb "dumpster-dive" appearing a few years later. In British English, the practice may be known as "skipping", from skip, another term for this type of container.
Alternative names for the practice include bin-diving, containering, D-mart, dumpstering, totting, and skipping. In Australia, garbage picking is called "skip dipping."
The term "binner" is often used to describe individuals who collect recyclable materials for their deposit value. For example, in Vancouver, British Columbia, binners, or bottle collectors, search garbage cans and dumpsters for recyclable materials that can be redeemed for their deposit value. On average, these binners earn about $40 a day for several garbage bags full of discarded containers. Some are scammers seeking for receipts to use in committing return fraud.
The karung guni, Zabbaleen, the rag and bone man, waste picker, junk man or bin hoker are terms for people who make their living by sorting and trading trash. A similar process known as gleaning was practised in rural areas and some ancient agricultural societies, where the residue from farmers' fields was collected.
Some dumpster divers, who self-identify as freegans, aim to reduce their ecological footprint by living from dumpster-dived-goods, sometimes exclusively.
The activity is performed by people out of necessity in the developing world. Some scavengers perform in organized groups, and some organize on various internet forums and social networking websites. By reusing, or repurposing, resources destined for the landfill, dumpster diving is sometimes considered to be an environmentalist endeavor, and is thus practiced by many pro-green communities. The wastefulness of consumer society and throw-away culture compels some individuals to rescue usable items (for example, computers or smartphones, which are frequently discarded due to the extensive use of planned obsolescence in the technology industry) from destruction and divert them to those who can make use of the items.
A wide variety of things may be disposed while still repairable or in working condition, making salvage of them a source of potentially free items for personal use, or to sell for profit. Irregular, blemished or damaged items that are still otherwise functional are regularly thrown away. Discarded food that might have slight imperfections, near its expiration date, or that is simply being replaced by newer stock is often tossed out despite being still edible. Many retailers are reluctant to sell this stock at reduced prices because of the risks that people will buy it instead of the higher-priced newer stock, that extra handling time is required, and that there are liability risks. In the United Kingdom, cookery books have been written on the cooking and consumption of such foods, which has contributed to the popularity of skipping. Artists often use discarded materials retrieved from trash receptacles to create works of found objects or assemblage.
Students have been known to partake in dumpster diving to obtain high tech items for technical projects, or simply to indulge their curiosity for unusual items. Dumpster diving can additionally be used in support of academic research. Garbage picking serves as the main tool for garbologists, who study the sociology and archeology of trash in modern life. Private and government investigators may pick through garbage to obtain information for their inquiries. Illegal cigarette consumption may be deduced from discarded packages.
Dumpster diving can be hazardous, due to potential exposure to biohazardous matter, broken glass, and overall unsanitary conditions that may exist in dumpsters.
Arguments against garbage picking often focus on the health and cleanliness implications of people rummaging in trash. This exposes the dumpster divers to potential health risks, and, especially if the dumpster diver does not return the non-usable items to their previous location, may leave trash scattered around. Divers can also be seriously injured or killed by garbage collection vehicles; in January 2012, in La Jolla, Swiss-American man Alfonso de Bourbon was killed by a truck while dumpster diving.
The unauthorized taking of materials from a dumpster or other waste disposal container is commonly referred to as "garbage theft". Dumpster diving is a different idiom. Due to the typical low value of the stolen goods, garbage theft is not typically recognized as a serious crime, with laws against it frequently focusing on combating identity theft instead. Depending on the state or nation's rules surrounding low-level crime, garbage theft may be considered a form of petty theft and subject to a penalty that often entails a brief period of incarceration, a modest fine, or both. As a privacy violation, discarded medical records as trash led to a $140,000 penalty against Massachusetts billing company Goldthwait Associates and a group of pathology offices in 2013 and a $400,000 settlement between Midwest Women's Healthcare Specialists and 1,532 clients in Kansas City in 2014.
Identity theft has historically been carried out through garbage theft, with thieves utilizing bank and credit card statements discovered in trash to assume the identity of a victim or access their credit.
Criminals have been known to dumpster dive for cash receipts as part of a scheme to steal items and return them for cash, a form of return fraud known as "shoplisting." Police investigating shoplifting in Bellingham, Washington found dozens of receipts from retailers such as The Home Depot, Rite Aid and Fred Meyer, along with a list of items on the receipts. Suspects believed to have taken receipts from trash receptacles near Walmart locations were arrested for return fraud in 2016 in Madison, Wisconsin.
Since dumpsters are usually located on private premises, divers may occasionally get in trouble for trespassing while dumpster diving, though the law is enforced with varying degrees of rigor. Some businesses may lock dumpsters to prevent pickers from congregating on their property, vandalism to their property, and to limit potential liability if a dumpster diver is injured while on their property.
Police searches of discarded waste as well as similar methods are also generally not considered violations; evidence seized in this manner has been permitted in many criminal trials. In the United States this has been affirmed by numerous courts including and up to the Supreme Court, in the decision California v. Greenwood. The doctrine is not as well established in regard to civil litigation.
Companies run by private investigators specializing in such techniques have emerged as a result of the need for discreet, undetected retrieval of documents and evidence for civil and criminal trials. Private investigators have also written books on "P.I. technique" in which dumpster diving or its equivalent "wastebasket recovery" figures prominently.
In 2009, a Belgian dumpster diver and eco-activist nicknamed Ollie was detained for a month for removing food from a garbage can and was accused of theft and burglary. On February 25, 2009, he was arrested for removing food from a garbage can at an AD Delhaize supermarket in Bruges. Ollie's trial evoked protests in Belgium against restrictions from taking discarded food items.
In Ontario, Canada, the Trespass to Property Act—legislation dating back to the British North America Act of 1867—grants property owners and security guards the power to ban anyone from their premises, for any reason, permanently. This is done by issuing a notice to the intruder, who will only be breaking the law upon return. Similar laws exist in Prince Edward Island and Saskatchewan. A recent case in Canada, which involved a police officer who retrieved a discarded weapon from a trash receptacle as evidence, created some controversy. The judge ruled the policeman's actions as legal although there was no warrant present, which led some to speculate the event as validation for any Canadian citizen to raid garbage disposals.
Skipping in England and Wales may qualify as theft within the Theft Act 1968 or as common-law theft in Scotland, though there is very little enforcement in practice.
In Germany, dumpster diving is referred to as "containern", and a waste container's contents are regarded as the property of the container's owner. Therefore, taking items from such a container is viewed as theft. However, the police will routinely disregard the illegality of garbage picking since the items found are generally of low value. There has only been one known instance where people were prosecuted. In 2009 individuals were arrested on assumed burglary as they had surmounted a supermarket's fence which was then followed by a theft complaint by the owner; the case was suspended.
In the United States, the 1988 California v. Greenwood case in the U.S. Supreme Court held that there is no common law expectation of privacy for discarded materials. There are, however, limits to what can legally be taken from a company's refuse. In a 1983 Minnesota case involving the theft of customer lists from a garbage can, Tennant Company v. Advance Machine Company (355 N.W.2d 720), the owner of the discarded information was awarded $500,000 in damages.
Dumpster diving is practiced differently in developed countries than in developing countries.
In the 1960s, Jerry Schneider, using recovered instruction manuals from The Pacific Telephone & Telegraph Company, used the company's own procedures to acquire hundreds of thousands of dollars' worth of telephone equipment over several years until his arrest.
The Castle Infinity videogame, after its shutdown in 2005, was brought back from the dead by a fan rescuing its servers from the trash.
In October 2013, in North London, three men were arrested and charged under the 1824 Vagrancy Act when they were caught taking discarded food: tomatoes, mushrooms, cheese and cakes from bins behind an Iceland supermarket. The charges were dropped on 29 January 2014 after much public criticism as well as a request by Iceland's chief executive, Malcolm Walker.
In 1996, the source code for the Atari 7800 was discovered in the dumpster of the Atari office when the company closed. | [
{
"paragraph_id": 0,
"text": "Dumpster diving (also totting, skipping, skip diving or skip salvage) is salvaging from large commercial, residential, industrial and construction containers for unused items discarded by their owners but deemed useful to the picker. It is not confined to dumpsters and skips specifically and may cover standard household waste containers, curb sides, landfills or small dumps.",
"title": ""
},
{
"paragraph_id": 1,
"text": "Different terms are used to refer to different forms of this activity. For picking materials from the curbside trash collection, expressions such as curb shopping, trash picking or street scavenging are sometimes used. In the UK, if someone is primarily seeking recyclable metal, they are scrapping, and if they are picking the leftover food from farming left in the fields, they are gleaning.",
"title": ""
},
{
"paragraph_id": 2,
"text": "People dumpster dive for items such as clothing, furniture, food, and similar items in good working condition. Some people do this out of necessity due to poverty, others do it for ideological reasons or professionally and systematically for profit.",
"title": ""
},
{
"paragraph_id": 3,
"text": "The term \"dumpster diving\" emerged in the 1980s, combining \"diving\" with \"dumpster\", a large commercial trash bin. The term \"Dumpster\" itself comes from the Dempster Dumpster, a brand of bins manufactured by Dempster Brothers beginning in 1937. \"Dumpster\" became genericized by the 1970s. According to the Oxford English Dictionary, the term \"dumpster diving\" is chiefly found in American English and first appeared in print in 1983, with the verb \"dumpster-dive\" appearing a few years later. In British English, the practice may be known as \"skipping\", from skip, another term for this type of container.",
"title": "Etymology"
},
{
"paragraph_id": 4,
"text": "Alternative names for the practice include bin-diving, containering, D-mart, dumpstering, totting, and skipping. In Australia, garbage picking is called \"skip dipping.\"",
"title": "Etymology"
},
{
"paragraph_id": 5,
"text": "The term \"binner\" is often used to describe individuals who collect recyclable materials for their deposit value. For example, in Vancouver, British Columbia, binners, or bottle collectors, search garbage cans and dumpsters for recyclable materials that can be redeemed for their deposit value. On average, these binners earn about $40 a day for several garbage bags full of discarded containers. Some are scammers seeking for receipts to use in committing return fraud.",
"title": "Participants"
},
{
"paragraph_id": 6,
"text": "The karung guni, Zabbaleen, the rag and bone man, waste picker, junk man or bin hoker are terms for people who make their living by sorting and trading trash. A similar process known as gleaning was practised in rural areas and some ancient agricultural societies, where the residue from farmers' fields was collected.",
"title": "Participants"
},
{
"paragraph_id": 7,
"text": "Some dumpster divers, who self-identify as freegans, aim to reduce their ecological footprint by living from dumpster-dived-goods, sometimes exclusively.",
"title": "Participants"
},
{
"paragraph_id": 8,
"text": "The activity is performed by people out of necessity in the developing world. Some scavengers perform in organized groups, and some organize on various internet forums and social networking websites. By reusing, or repurposing, resources destined for the landfill, dumpster diving is sometimes considered to be an environmentalist endeavor, and is thus practiced by many pro-green communities. The wastefulness of consumer society and throw-away culture compels some individuals to rescue usable items (for example, computers or smartphones, which are frequently discarded due to the extensive use of planned obsolescence in the technology industry) from destruction and divert them to those who can make use of the items.",
"title": "Overview"
},
{
"paragraph_id": 9,
"text": "A wide variety of things may be disposed while still repairable or in working condition, making salvage of them a source of potentially free items for personal use, or to sell for profit. Irregular, blemished or damaged items that are still otherwise functional are regularly thrown away. Discarded food that might have slight imperfections, near its expiration date, or that is simply being replaced by newer stock is often tossed out despite being still edible. Many retailers are reluctant to sell this stock at reduced prices because of the risks that people will buy it instead of the higher-priced newer stock, that extra handling time is required, and that there are liability risks. In the United Kingdom, cookery books have been written on the cooking and consumption of such foods, which has contributed to the popularity of skipping. Artists often use discarded materials retrieved from trash receptacles to create works of found objects or assemblage.",
"title": "Overview"
},
{
"paragraph_id": 10,
"text": "Students have been known to partake in dumpster diving to obtain high tech items for technical projects, or simply to indulge their curiosity for unusual items. Dumpster diving can additionally be used in support of academic research. Garbage picking serves as the main tool for garbologists, who study the sociology and archeology of trash in modern life. Private and government investigators may pick through garbage to obtain information for their inquiries. Illegal cigarette consumption may be deduced from discarded packages.",
"title": "Overview"
},
{
"paragraph_id": 11,
"text": "Dumpster diving can be hazardous, due to potential exposure to biohazardous matter, broken glass, and overall unsanitary conditions that may exist in dumpsters.",
"title": "Overview"
},
{
"paragraph_id": 12,
"text": "Arguments against garbage picking often focus on the health and cleanliness implications of people rummaging in trash. This exposes the dumpster divers to potential health risks, and, especially if the dumpster diver does not return the non-usable items to their previous location, may leave trash scattered around. Divers can also be seriously injured or killed by garbage collection vehicles; in January 2012, in La Jolla, Swiss-American man Alfonso de Bourbon was killed by a truck while dumpster diving.",
"title": "Overview"
},
{
"paragraph_id": 13,
"text": "The unauthorized taking of materials from a dumpster or other waste disposal container is commonly referred to as \"garbage theft\". Dumpster diving is a different idiom. Due to the typical low value of the stolen goods, garbage theft is not typically recognized as a serious crime, with laws against it frequently focusing on combating identity theft instead. Depending on the state or nation's rules surrounding low-level crime, garbage theft may be considered a form of petty theft and subject to a penalty that often entails a brief period of incarceration, a modest fine, or both. As a privacy violation, discarded medical records as trash led to a $140,000 penalty against Massachusetts billing company Goldthwait Associates and a group of pathology offices in 2013 and a $400,000 settlement between Midwest Women's Healthcare Specialists and 1,532 clients in Kansas City in 2014.",
"title": "Overview"
},
{
"paragraph_id": 14,
"text": "Identity theft has historically been carried out through garbage theft, with thieves utilizing bank and credit card statements discovered in trash to assume the identity of a victim or access their credit.",
"title": "Overview"
},
{
"paragraph_id": 15,
"text": "Criminals have been known to dumpster dive for cash receipts as part of a scheme to steal items and return them for cash, a form of return fraud known as \"shoplisting.\" Police investigating shoplifting in Bellingham, Washington found dozens of receipts from retailers such as The Home Depot, Rite Aid and Fred Meyer, along with a list of items on the receipts. Suspects believed to have taken receipts from trash receptacles near Walmart locations were arrested for return fraud in 2016 in Madison, Wisconsin.",
"title": "Overview"
},
{
"paragraph_id": 16,
"text": "Since dumpsters are usually located on private premises, divers may occasionally get in trouble for trespassing while dumpster diving, though the law is enforced with varying degrees of rigor. Some businesses may lock dumpsters to prevent pickers from congregating on their property, vandalism to their property, and to limit potential liability if a dumpster diver is injured while on their property.",
"title": "Legal status"
},
{
"paragraph_id": 17,
"text": "Police searches of discarded waste as well as similar methods are also generally not considered violations; evidence seized in this manner has been permitted in many criminal trials. In the United States this has been affirmed by numerous courts including and up to the Supreme Court, in the decision California v. Greenwood. The doctrine is not as well established in regard to civil litigation.",
"title": "Legal status"
},
{
"paragraph_id": 18,
"text": "Companies run by private investigators specializing in such techniques have emerged as a result of the need for discreet, undetected retrieval of documents and evidence for civil and criminal trials. Private investigators have also written books on \"P.I. technique\" in which dumpster diving or its equivalent \"wastebasket recovery\" figures prominently.",
"title": "Legal status"
},
{
"paragraph_id": 19,
"text": "In 2009, a Belgian dumpster diver and eco-activist nicknamed Ollie was detained for a month for removing food from a garbage can and was accused of theft and burglary. On February 25, 2009, he was arrested for removing food from a garbage can at an AD Delhaize supermarket in Bruges. Ollie's trial evoked protests in Belgium against restrictions from taking discarded food items.",
"title": "Legal status"
},
{
"paragraph_id": 20,
"text": "In Ontario, Canada, the Trespass to Property Act—legislation dating back to the British North America Act of 1867—grants property owners and security guards the power to ban anyone from their premises, for any reason, permanently. This is done by issuing a notice to the intruder, who will only be breaking the law upon return. Similar laws exist in Prince Edward Island and Saskatchewan. A recent case in Canada, which involved a police officer who retrieved a discarded weapon from a trash receptacle as evidence, created some controversy. The judge ruled the policeman's actions as legal although there was no warrant present, which led some to speculate the event as validation for any Canadian citizen to raid garbage disposals.",
"title": "Legal status"
},
{
"paragraph_id": 21,
"text": "Skipping in England and Wales may qualify as theft within the Theft Act 1968 or as common-law theft in Scotland, though there is very little enforcement in practice.",
"title": "Legal status"
},
{
"paragraph_id": 22,
"text": "In Germany, dumpster diving is referred to as \"containern\", and a waste container's contents are regarded as the property of the container's owner. Therefore, taking items from such a container is viewed as theft. However, the police will routinely disregard the illegality of garbage picking since the items found are generally of low value. There has only been one known instance where people were prosecuted. In 2009 individuals were arrested on assumed burglary as they had surmounted a supermarket's fence which was then followed by a theft complaint by the owner; the case was suspended.",
"title": "Legal status"
},
{
"paragraph_id": 23,
"text": "In the United States, the 1988 California v. Greenwood case in the U.S. Supreme Court held that there is no common law expectation of privacy for discarded materials. There are, however, limits to what can legally be taken from a company's refuse. In a 1983 Minnesota case involving the theft of customer lists from a garbage can, Tennant Company v. Advance Machine Company (355 N.W.2d 720), the owner of the discarded information was awarded $500,000 in damages.",
"title": "Legal status"
},
{
"paragraph_id": 24,
"text": "Dumpster diving is practiced differently in developed countries than in developing countries.",
"title": "Items"
},
{
"paragraph_id": 25,
"text": "In the 1960s, Jerry Schneider, using recovered instruction manuals from The Pacific Telephone & Telegraph Company, used the company's own procedures to acquire hundreds of thousands of dollars' worth of telephone equipment over several years until his arrest.",
"title": "Notable instances"
},
{
"paragraph_id": 26,
"text": "The Castle Infinity videogame, after its shutdown in 2005, was brought back from the dead by a fan rescuing its servers from the trash.",
"title": "Notable instances"
},
{
"paragraph_id": 27,
"text": "In October 2013, in North London, three men were arrested and charged under the 1824 Vagrancy Act when they were caught taking discarded food: tomatoes, mushrooms, cheese and cakes from bins behind an Iceland supermarket. The charges were dropped on 29 January 2014 after much public criticism as well as a request by Iceland's chief executive, Malcolm Walker.",
"title": "Notable instances"
},
{
"paragraph_id": 28,
"text": "In 1996, the source code for the Atari 7800 was discovered in the dumpster of the Atari office when the company closed.",
"title": "Notable instances"
}
] | Dumpster diving is salvaging from large commercial, residential, industrial and construction containers for unused items discarded by their owners but deemed useful to the picker. It is not confined to dumpsters and skips specifically and may cover standard household waste containers, curb sides, landfills or small dumps. Different terms are used to refer to different forms of this activity. For picking materials from the curbside trash collection, expressions such as curb shopping, trash picking or street scavenging are sometimes used. In the UK, if someone is primarily seeking recyclable metal, they are scrapping, and if they are picking the leftover food from farming left in the fields, they are gleaning. People dumpster dive for items such as clothing, furniture, food, and similar items in good working condition. Some people do this out of necessity due to poverty, others do it for ideological reasons or professionally and systematically for profit. | 2001-07-27T09:32:45Z | 2023-12-19T08:17:26Z | [
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8,247 | Digital synthesizer | A digital synthesizer is a synthesizer that uses digital signal processing (DSP) techniques to make musical sounds. This in contrast to older analog synthesizers, which produce music using analog electronics, and samplers, which play back digital recordings of acoustic, electric, or electronic instruments. Some digital synthesizers emulate analog synthesizers; others include sampling capability in addition to digital synthesis.
The very earliest digital synthesis experiments were made with computers, as part of academic research into sound generation.
In 1957, the first programming language for computer music, MUSIC, was developed by Max Mathews on an IBM 704 at Bell Labs in 1957. It generates digital audio waveforms through direct synthesis.
Circa 1969, EMS MUSYS 3 system was developed by Peter Grogono (software), David Cockerell (hardware and interfacing) and Peter Zinovieff (system design and operation) at their London (Putney) Studio. The system ran on two mini-computers, Digital Equipment PDP-8's. These had a pair of fast D/A and A/D converters, 12,000 (12k) bytes of core memory (RAM), backed up by a hard drive of 32k and by tape storage (DecTape). The earliest digital sampling was done on that system during 1971–1972 for Harrison Birtwistle's "Chronometer" released in 1975.
In 1972–1974, Dartmouth Digital Synthesizer was developed by Dartmouth College Professors Jon Appleton and Frederick J. Hooven, in association with NED co-founders Sydney A. Alonso and Cameron W. Jones.
In 1977, Bell Labs Digital Synthesizer was developed by Hal Ales at Bell Labs.
In 1977, New England Digital (NED) released the Synclavier, the first commercial synthesizer to use purely digital sound generation and also the world's first commercial FM synthesizer.
Early commercial digital synthesizers used simple hard-wired digital circuitry to implement techniques such as additive synthesis and FM synthesis. Other techniques, such as wavetable synthesis and physical modeling, only became possible with the advent of high-speed microprocessor and digital signal processing technology. Two other early commercial digital synthesizers were the Fairlight CMI, introduced in 1979, and the New England Digital Synclavier II, introduced in 1979 as an upgrade to the original Synclavier. The Fairlight CMI was the one of the earlier sampling synthesizers, while the Synclavier originally used FM synthesis technology licensed from Yamaha, before adding the world's first 16-bit, real-time hard drive streaming sampler later in 1982. The Fairlight CMI and the Synclavier were both expensive systems, retailing for more than $20,000 in the early 1980s. The cost of digital synthesizers began falling rapidly in the early 1980s. E-mu Systems introduced the Emulator sampling synthesizer in 1982 at a retail price of $7,900. Although not as flexible or powerful as either the Fairlight CMI or the Synclavier, its lower cost and portability made it popular.
With the addition of sophisticated sequencers on board, now added to built-in effects and other features, the 'workstation' synthesizer had been born. These always include a multi-track sequencer, and can often record and play back samples, and in later years full audio tracks, to be used to record an entire song. These are usually also ROMplers, playing back samples, to give a wide variety of realistic instrument and other sounds such as drums, string instruments and wind instruments to sequence and compose songs, along with popular keyboard instrument sounds such as electric pianos and organs.
As there was still interest in analog synthesizers, and with the increase of computing power, over the 1990s another type of synthesizer arose: the analog modeling, or "virtual analog" synthesizer. These use computing power to simulate traditional analog waveforms and circuitry such as envelopes and filters, with the most popular examples of this type of instrument including the Nord Lead and Access Virus.
Digital synthesizers can now be completely emulated in software ("softsynth"), and run on conventional PC hardware. Such soft implementations require careful programming and a fast CPU to get the same latency response as their dedicated equivalents. To reduce latency, some professional sound card manufacturers have developed specialized Digital Signal Processing ([DSP]) hardware. Dedicated digital synthesizers have the advantage of a performance-friendly user interface (physical controls like buttons for selecting features and enabling functionality, and knobs for setting variable parameters). On the other hand, software synthesizers have the advantages afforded by a rich graphical display.
With focus on performance-oriented keyboards and digital computer technology, manufacturers of commercial electronic instruments created some of the earliest digital synthesizers for studio and experimental use with computers being able to handle built-in sound synthesis algorithms.
In 1973, the Japanese company Yamaha licensed the patent for frequency modulation synthesis (FM synthesis) from John Chowning, who had experimented with it at Stanford University since 1971. Yamaha's engineers began adapting Chowning's algorithm for use in a commercial digital synthesizer, adding improvements such as the "key scaling" method to avoid the introduction of distortion that normally occurred in analog systems during frequency modulation, though it would take several years before Yamaha were to release their FM digital synthesizers. In the 1970s, Yamaha were granted a number of patents, under the company's former name "Nippon Gakki Seizo Kabushiki Kaisha", evolving Chowning's early work on FM synthesis technology. Yamaha built the first prototype digital synthesizer in 1974.
Released in 1979, the Casio VL-1 was the first low budget digital synthesizer, selling for $69.95. Yamaha eventually commercialized their FM synthesis technology and released the company's first FM digital synthesizer in 1980, the Yamaha GS-1, but at an expensive retail price of $16,000.
Introduced in 1983, the Yamaha DX7 was the breakthrough digital synthesizer to have a major impact, both innovative and affordable, and thus spelling the decline of analog synthesizers. It used FM synthesis and, although it was incapable of the sampling synthesis of the Fairlight CMI, its price was around $2,000, putting it within range of a much larger number of musicians. The DX-7 was also known for its "key scaling" method to avoid distortion and for its recognizably bright tonality that was partly due to its high sampling rate of 57 kHz. It became indispensable to many music artists of the 1980s, and would become one of the best-selling synthesizers of all time.
In 1987, Roland released its own influential synthesizer of the time, the D-50. This popular synth broke new ground in affordably combining short samples and digital oscillators, as well as the innovation of built-in digital effects (reverb., chorus, equalizer). Roland called this Linear Arithmetic (LA) synthesis. This instrument is responsible for some of the very recognisable preset synthesizer sounds of the late 1980s, such as the Pizzagogo sound used on Enya's "Orinoco Flow."
It gradually became feasible to include high quality samples of existing instruments as opposed to synthesizing them. In 1988, Korg introduced the last of the hugely popular trio of digital synthesizers of the 1980s after the DX7 and D50, the M1. This heralded both the increasing popularisation of digital sample-based synthesis, and the rise of 'workstation' synthesizers. After this time, many popular modern digital synthesizers have been described as not being full synthesizers in the most precise sense, as they play back samples stored in their memory. However, they still include options to shape the sounds through use of envelopes, LFOs, filters and effects such as reverb. The Yamaha Motif and Roland Fantom series of keyboards are typical examples of this type, described as 'ROMplers'; at the same time, they are also examples of "workstation" synthesizers.
As the cost of processing power and memory fell, new types of synthesizers emerged, offering a variety of novel sound synthesis options. The Korg Oasys was one such example, packaging multiple digital synthesizers into a single unit.
An analog synthesizer creates sound using electronic circuitry, such as voltage-controlled oscillators and voltage-controlled filters. In contrast, a digital synthesizer generates a stream of numbers, often using some form of digital signal processor, which are then converted to sound using a digital-to-analog converter (DAC).
A digital synthesizer is in essence a computer with (often) a piano or organ keyboard and an LCD as a user interface. Because computer technology is rapidly advancing, it is often possible to offer more features in a digital synthesizer than in an analog synthesizer at a given price. However, both technologies have their own merit. Some forms of synthesis, such as, for instance, sampling and additive synthesis are not feasible in analog synthesizers, while on the other hand, many musicians prefer the character of analog synthesizers over their digital equivalent.
The new wave era of the 1980s first brought the digital synthesizer to the public ear. Bands like Talking Heads and Duran Duran used the digitally made sounds on some of their most popular albums. Other more pop-inspired bands like Hall & Oates began incorporating the digital synthesizer into their sound in the 1980s. Through breakthroughs in technology in the 1990s many modern synthesizers use DSP.
Working in more or less the same way, every digital synthesizer appears similar to a computer. At a steady sample rate, digital synthesis produces a stream of numbers. Sound from speakers is then produced by a conversion to analog form. Direct digital synthesis is the typical architecture for digital synthesizers. Through signal generation, voice and instrument-level processing, a signal flow is created and controlled either by MIDI capabilities or voice and instrument-level controls. | [
{
"paragraph_id": 0,
"text": "A digital synthesizer is a synthesizer that uses digital signal processing (DSP) techniques to make musical sounds. This in contrast to older analog synthesizers, which produce music using analog electronics, and samplers, which play back digital recordings of acoustic, electric, or electronic instruments. Some digital synthesizers emulate analog synthesizers; others include sampling capability in addition to digital synthesis.",
"title": ""
},
{
"paragraph_id": 1,
"text": "The very earliest digital synthesis experiments were made with computers, as part of academic research into sound generation.",
"title": "History"
},
{
"paragraph_id": 2,
"text": "In 1957, the first programming language for computer music, MUSIC, was developed by Max Mathews on an IBM 704 at Bell Labs in 1957. It generates digital audio waveforms through direct synthesis.",
"title": "History"
},
{
"paragraph_id": 3,
"text": "Circa 1969, EMS MUSYS 3 system was developed by Peter Grogono (software), David Cockerell (hardware and interfacing) and Peter Zinovieff (system design and operation) at their London (Putney) Studio. The system ran on two mini-computers, Digital Equipment PDP-8's. These had a pair of fast D/A and A/D converters, 12,000 (12k) bytes of core memory (RAM), backed up by a hard drive of 32k and by tape storage (DecTape). The earliest digital sampling was done on that system during 1971–1972 for Harrison Birtwistle's \"Chronometer\" released in 1975.",
"title": "History"
},
{
"paragraph_id": 4,
"text": "In 1972–1974, Dartmouth Digital Synthesizer was developed by Dartmouth College Professors Jon Appleton and Frederick J. Hooven, in association with NED co-founders Sydney A. Alonso and Cameron W. Jones.",
"title": "History"
},
{
"paragraph_id": 5,
"text": "In 1977, Bell Labs Digital Synthesizer was developed by Hal Ales at Bell Labs.",
"title": "History"
},
{
"paragraph_id": 6,
"text": "In 1977, New England Digital (NED) released the Synclavier, the first commercial synthesizer to use purely digital sound generation and also the world's first commercial FM synthesizer.",
"title": "History"
},
{
"paragraph_id": 7,
"text": "Early commercial digital synthesizers used simple hard-wired digital circuitry to implement techniques such as additive synthesis and FM synthesis. Other techniques, such as wavetable synthesis and physical modeling, only became possible with the advent of high-speed microprocessor and digital signal processing technology. Two other early commercial digital synthesizers were the Fairlight CMI, introduced in 1979, and the New England Digital Synclavier II, introduced in 1979 as an upgrade to the original Synclavier. The Fairlight CMI was the one of the earlier sampling synthesizers, while the Synclavier originally used FM synthesis technology licensed from Yamaha, before adding the world's first 16-bit, real-time hard drive streaming sampler later in 1982. The Fairlight CMI and the Synclavier were both expensive systems, retailing for more than $20,000 in the early 1980s. The cost of digital synthesizers began falling rapidly in the early 1980s. E-mu Systems introduced the Emulator sampling synthesizer in 1982 at a retail price of $7,900. Although not as flexible or powerful as either the Fairlight CMI or the Synclavier, its lower cost and portability made it popular.",
"title": "History"
},
{
"paragraph_id": 8,
"text": "With the addition of sophisticated sequencers on board, now added to built-in effects and other features, the 'workstation' synthesizer had been born. These always include a multi-track sequencer, and can often record and play back samples, and in later years full audio tracks, to be used to record an entire song. These are usually also ROMplers, playing back samples, to give a wide variety of realistic instrument and other sounds such as drums, string instruments and wind instruments to sequence and compose songs, along with popular keyboard instrument sounds such as electric pianos and organs.",
"title": "History"
},
{
"paragraph_id": 9,
"text": "As there was still interest in analog synthesizers, and with the increase of computing power, over the 1990s another type of synthesizer arose: the analog modeling, or \"virtual analog\" synthesizer. These use computing power to simulate traditional analog waveforms and circuitry such as envelopes and filters, with the most popular examples of this type of instrument including the Nord Lead and Access Virus.",
"title": "History"
},
{
"paragraph_id": 10,
"text": "Digital synthesizers can now be completely emulated in software (\"softsynth\"), and run on conventional PC hardware. Such soft implementations require careful programming and a fast CPU to get the same latency response as their dedicated equivalents. To reduce latency, some professional sound card manufacturers have developed specialized Digital Signal Processing ([DSP]) hardware. Dedicated digital synthesizers have the advantage of a performance-friendly user interface (physical controls like buttons for selecting features and enabling functionality, and knobs for setting variable parameters). On the other hand, software synthesizers have the advantages afforded by a rich graphical display.",
"title": "History"
},
{
"paragraph_id": 11,
"text": "With focus on performance-oriented keyboards and digital computer technology, manufacturers of commercial electronic instruments created some of the earliest digital synthesizers for studio and experimental use with computers being able to handle built-in sound synthesis algorithms.",
"title": "History"
},
{
"paragraph_id": 12,
"text": "In 1973, the Japanese company Yamaha licensed the patent for frequency modulation synthesis (FM synthesis) from John Chowning, who had experimented with it at Stanford University since 1971. Yamaha's engineers began adapting Chowning's algorithm for use in a commercial digital synthesizer, adding improvements such as the \"key scaling\" method to avoid the introduction of distortion that normally occurred in analog systems during frequency modulation, though it would take several years before Yamaha were to release their FM digital synthesizers. In the 1970s, Yamaha were granted a number of patents, under the company's former name \"Nippon Gakki Seizo Kabushiki Kaisha\", evolving Chowning's early work on FM synthesis technology. Yamaha built the first prototype digital synthesizer in 1974.",
"title": "History"
},
{
"paragraph_id": 13,
"text": "Released in 1979, the Casio VL-1 was the first low budget digital synthesizer, selling for $69.95. Yamaha eventually commercialized their FM synthesis technology and released the company's first FM digital synthesizer in 1980, the Yamaha GS-1, but at an expensive retail price of $16,000.",
"title": "History"
},
{
"paragraph_id": 14,
"text": "Introduced in 1983, the Yamaha DX7 was the breakthrough digital synthesizer to have a major impact, both innovative and affordable, and thus spelling the decline of analog synthesizers. It used FM synthesis and, although it was incapable of the sampling synthesis of the Fairlight CMI, its price was around $2,000, putting it within range of a much larger number of musicians. The DX-7 was also known for its \"key scaling\" method to avoid distortion and for its recognizably bright tonality that was partly due to its high sampling rate of 57 kHz. It became indispensable to many music artists of the 1980s, and would become one of the best-selling synthesizers of all time.",
"title": "History"
},
{
"paragraph_id": 15,
"text": "In 1987, Roland released its own influential synthesizer of the time, the D-50. This popular synth broke new ground in affordably combining short samples and digital oscillators, as well as the innovation of built-in digital effects (reverb., chorus, equalizer). Roland called this Linear Arithmetic (LA) synthesis. This instrument is responsible for some of the very recognisable preset synthesizer sounds of the late 1980s, such as the Pizzagogo sound used on Enya's \"Orinoco Flow.\"",
"title": "History"
},
{
"paragraph_id": 16,
"text": "It gradually became feasible to include high quality samples of existing instruments as opposed to synthesizing them. In 1988, Korg introduced the last of the hugely popular trio of digital synthesizers of the 1980s after the DX7 and D50, the M1. This heralded both the increasing popularisation of digital sample-based synthesis, and the rise of 'workstation' synthesizers. After this time, many popular modern digital synthesizers have been described as not being full synthesizers in the most precise sense, as they play back samples stored in their memory. However, they still include options to shape the sounds through use of envelopes, LFOs, filters and effects such as reverb. The Yamaha Motif and Roland Fantom series of keyboards are typical examples of this type, described as 'ROMplers'; at the same time, they are also examples of \"workstation\" synthesizers.",
"title": "History"
},
{
"paragraph_id": 17,
"text": "As the cost of processing power and memory fell, new types of synthesizers emerged, offering a variety of novel sound synthesis options. The Korg Oasys was one such example, packaging multiple digital synthesizers into a single unit.",
"title": "History"
},
{
"paragraph_id": 18,
"text": "An analog synthesizer creates sound using electronic circuitry, such as voltage-controlled oscillators and voltage-controlled filters. In contrast, a digital synthesizer generates a stream of numbers, often using some form of digital signal processor, which are then converted to sound using a digital-to-analog converter (DAC).",
"title": "Analog vs. digital"
},
{
"paragraph_id": 19,
"text": "A digital synthesizer is in essence a computer with (often) a piano or organ keyboard and an LCD as a user interface. Because computer technology is rapidly advancing, it is often possible to offer more features in a digital synthesizer than in an analog synthesizer at a given price. However, both technologies have their own merit. Some forms of synthesis, such as, for instance, sampling and additive synthesis are not feasible in analog synthesizers, while on the other hand, many musicians prefer the character of analog synthesizers over their digital equivalent.",
"title": "Analog vs. digital"
},
{
"paragraph_id": 20,
"text": "The new wave era of the 1980s first brought the digital synthesizer to the public ear. Bands like Talking Heads and Duran Duran used the digitally made sounds on some of their most popular albums. Other more pop-inspired bands like Hall & Oates began incorporating the digital synthesizer into their sound in the 1980s. Through breakthroughs in technology in the 1990s many modern synthesizers use DSP.",
"title": "Usage in Popular Music"
},
{
"paragraph_id": 21,
"text": "Working in more or less the same way, every digital synthesizer appears similar to a computer. At a steady sample rate, digital synthesis produces a stream of numbers. Sound from speakers is then produced by a conversion to analog form. Direct digital synthesis is the typical architecture for digital synthesizers. Through signal generation, voice and instrument-level processing, a signal flow is created and controlled either by MIDI capabilities or voice and instrument-level controls.",
"title": "Digital synthesis"
}
] | A digital synthesizer is a synthesizer that uses digital signal processing (DSP) techniques to make musical sounds. This in contrast to older analog synthesizers, which produce music using analog electronics, and samplers, which play back digital recordings of acoustic, electric, or electronic instruments. Some digital synthesizers emulate analog synthesizers; others include sampling capability in addition to digital synthesis. | 2001-07-30T13:45:30Z | 2023-12-30T05:25:28Z | [
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8,249 | Definition of music | A definition of music endeavors to give an accurate and concise explanation of music's basic attributes or essential nature and it involves a process of defining what is meant by the term music. Many authorities have suggested definitions, but defining music turns out to be more difficult than might first be imagined, and there is ongoing debate. A number of explanations start with the notion of music as organized sound, but they also highlight that this is perhaps too broad a definition and cite examples of organized sound that are not defined as music, such as human speech and sounds found in both natural and industrial environments . The problem of defining music is further complicated by the influence of culture in music cognition.
The Concise Oxford Dictionary defines music as "the art of combining vocal or instrumental sounds (or both) to produce beauty of form, harmony, and expression of emotion". However, some music genres, such as noise music and musique concrète, challenge these ideas by using sounds not widely considered as musical, beautiful or harmonious, like randomly produced electronic distortion, feedback, static, cacophony, and sounds produced using compositional processes which utilize indeterminacy.
An often-cited example of the dilemma in defining music is the work 4′33″ (1952) by the American composer John Cage (1912–1992). The written score has three movements and directs the performer(s) to appear on stage, indicate by gesture or other means when the piece begins, then make no sound throughout the duration of the piece, marking sections and the end by gesture. The audience hears only whatever ambient sounds may occur in the room. Some argue that 4′33″ is not music because, among other reasons, it contains no sounds that are conventionally considered "musical" and the composer and performer(s) exert no control over the organization of the sounds heard. Others argue it is music because the conventional definitions of musical sounds are unnecessarily and arbitrarily limited, and control over the organization of the sounds is achieved by the composer and performer(s) through their gestures that divide what is heard into specific sections and a comprehensible form.
Because of differing fundamental concepts of music, the languages of many cultures do not contain a word that can be accurately translated as "music" as that word is generally understood by Western cultures. Inuit and most North American Indian languages do not have a general term for music. Among the Aztecs, the ancient Mexican theory of rhetoric, poetry, dance, and instrumental music used the Nahuatl term In xochitl-in kwikatl to refer to a complex mix of music and other poetic verbal and non-verbal elements, and reserved the word Kwikakayotl (or cuicacayotl) only for the sung expressions. There is no term for music in Nigerian languages Tiv, Yoruba, Igbo, Efik, Birom, Hausa, Idoma, Eggon or Jarawa. Many other languages have terms which only partly cover what Western culture typically means by the term music.() The Mapuche of Argentina do not have a word for music, but they do have words for instrumental versus improvised forms (kantun), European and non-Mapuche music (kantun winka), ceremonial songs (öl), and tayil.
While some languages in West Africa have no term for music, some West African languages accept the general concepts of music.() Musiqi is the Persian word for the science and art of music, muzik being the sound and performance of music,() though some things European-influenced listeners would include, such as Quran chanting, are excluded.
Ben Watson points out that Ludwig van Beethoven's Große Fuge (1825) "sounded like noise" to his audience at the time. Indeed, Beethoven's publishers persuaded him to remove it from its original setting as the last movement of a string quartet. He did so, replacing it with a sparkling Allegro. They subsequently published it separately. Musicologist Jean-Jacques Nattiez considers the difference between noise and music nebulous, explaining that "The border between music and noise is always culturally defined—which implies that, even within a single society, this border does not always pass through the same place; in short, there is rarely a consensus ... By all accounts there is no single and intercultural universal concept defining what music might be".
An often-cited definition of music is that it is "organized sound", a term originally coined by modernist composer Edgard Varèse in reference to his own musical aesthetic. Varèse's concept of music as "organized sound" fits into his vision of "sound as living matter" and of "musical space as open rather than bounded". He conceived the elements of his music in terms of "sound-masses", likening their organization to the natural phenomenon of crystallization. Varèse thought that "to stubbornly conditioned ears, anything new in music has always been called noise", and he posed the question, "what is music but organized noises?"
The fifteenth edition of the Encyclopædia Britannica states that "while there are no sounds that can be described as inherently unmusical, musicians in each culture have tended to restrict the range of sounds they will admit." A human organizing element is often felt to be implicit in music (sounds produced by non-human agents, such as waterfalls or birds, are often described as "musical", but perhaps less often as "music"). The composer R. Murray states that the sound of classical music "has decays; it is granular; it has attacks; it fluctuates, swollen with impurities—and all this creates a musicality that comes before any 'cultural' musicality." However, in the view of semiologist Jean-Jacques Nattiez, "just as music is whatever people choose to recognize as such, noise is whatever is recognized as disturbing, unpleasant, or both". (See "music as social construct" below.)
Levi R. Bryant defines music not as a language, but as a marked-based, problem-solving method, comparable to mathematics.
Most definitions of music include a reference to sound and a list of universals of music can be generated by stating the elements (or aspects) of sound: pitch, timbre, loudness, duration, spatial location and texture.). However, in terms more specifically relating to music: following Wittgenstein, cognitive psychologist Eleanor Rosch proposes that categories are not clean cut but that something may be more or less a member of a category. As such the search for musical universals would fail and would not provide one with a valid definition. This is primarily because other cultures have different understandings in relation to the sounds that English-language writers refer to as music.
Many people do, however, share a general idea of music. The Websters definition of music is a typical example: "the science or art of ordering tones or sounds in succession, in combination, and in temporal relationships to produce a composition having unity and continuity" (Webster's Collegiate Dictionary, online edition).
This approach to the definition focuses not on the construction but on the experience of music. An extreme statement of the position has been articulated by the Italian composer Luciano Berio: "Music is everything that one listens to with the intention of listening to music". This approach permits the boundary between music and noise to change over time as the conventions of musical interpretation evolve within a culture, to be different in different cultures at any given moment, and to vary from person to person according to their experience and proclivities. It is further consistent with the subjective reality that even what would commonly be considered music is experienced as non-music if the mind is concentrating on other matters and thus not perceiving the sound's essence as music.
In his 1983 book, Music as Heard, which sets out from the phenomenological position of Husserl, Merleau-Ponty, and Ricœur, Thomas Clifton defines music as "an ordered arrangement of sounds and silences whose meaning is presentative rather than denotative ... This definition distinguishes music, as an end in itself, from compositional technique, and from sounds as purely physical objects." More precisely, "music is the actualization of the possibility of any sound whatever to present to some human being a meaning which he experiences with his body—that is to say, with his mind, his feelings, his senses, his will, and his metabolism". It is therefore "a certain reciprocal relation established between a person, his behavior, and a sounding object".
Clifton accordingly differentiates music from non-music on the basis of the human behavior involved, rather than on either the nature of compositional technique or of sounds as purely physical objects. Consequently, the distinction becomes a question of what is meant by musical behavior: "a musically behaving person is one whose very being is absorbed in the significance of the sounds being experienced." However, "It is not altogether accurate to say that this person is listening to the sounds. First, the person is doing more than listening: he is perceiving, interpreting, judging, and feeling. Second, the preposition 'to' puts too much stress on the sounds as such. Thus, the musically behaving person experiences musical significance by means of, or through, the sounds".
In this framework, Clifton finds that there are two things that separate music from non-music: (1) musical meaning is presentative, and (2) music and non-music are distinguished in the idea of personal involvement. "It is the notion of personal involvement which lends significance to the word ordered in this definition of music". This is not to be understood, however, as a sanctification of extreme relativism, since "it is precisely the 'subjective' aspect of experience which lured many writers earlier in this century down the path of sheer opinion-mongering. Later on this trend was reversed by a renewed interest in 'objective,' scientific, or otherwise non-introspective musical analysis. But we have good reason to believe that a musical experience is not a purely private thing, like seeing pink elephants, and that reporting about such an experience need not be subjective in the sense of it being a mere matter of opinion".
Clifton's task, then, is to describe musical experience and the objects of this experience which, together, are called "phenomena", and the activity of describing phenomena is called "phenomenology". It is important to stress that this definition of music says nothing about aesthetic standards.
Music is not a fact or a thing in the world, but a meaning constituted by human beings. ... To talk about such experience in a meaningful way demands several things. First, we have to be willing to let the composition speak to us, to let it reveal its own order and significance. ... Second, we have to be willing to question our assumptions about the nature and role of musical materials. ... Last, and perhaps most important, we have to be ready to admit that describing a meaningful experience is itself meaningful.
"Music, often an art/entertainment, is a total social fact whose definitions vary according to era and culture", according to Jean. It is often contrasted with noise. According to musicologist Jean-Jacques Nattiez: "The border between music and noise is always culturally defined—which implies that, even within a single society, this border does not always pass through the same place; in short, there is rarely a consensus ... By all accounts there is no single and intercultural universal concept defining what music might be". Given the above demonstration that "there is no limit to the number or the genre of variables that might intervene in a definition of the musical", an organization of definitions and elements is necessary.
Nattiez (1990, 17) describes definitions according to a tripartite semiological scheme similar to the following:
There are three levels of description, the poietic, the neutral, and the esthesic:
Table describing types of definitions of music:
Because of this range of definitions, the study of music comes in a wide variety of forms. There is the study of sound and vibration or acoustics, the cognitive study of music, the study of music theory and performance practice or music theory and ethnomusicology and the study of the reception and history of music, generally called musicology.
Composer Iannis Xenakis in "Towards a Metamusic" (chapter 7 of Formalized Music) defined music in the following way:
Sources | [
{
"paragraph_id": 0,
"text": "A definition of music endeavors to give an accurate and concise explanation of music's basic attributes or essential nature and it involves a process of defining what is meant by the term music. Many authorities have suggested definitions, but defining music turns out to be more difficult than might first be imagined, and there is ongoing debate. A number of explanations start with the notion of music as organized sound, but they also highlight that this is perhaps too broad a definition and cite examples of organized sound that are not defined as music, such as human speech and sounds found in both natural and industrial environments . The problem of defining music is further complicated by the influence of culture in music cognition.",
"title": ""
},
{
"paragraph_id": 1,
"text": "The Concise Oxford Dictionary defines music as \"the art of combining vocal or instrumental sounds (or both) to produce beauty of form, harmony, and expression of emotion\". However, some music genres, such as noise music and musique concrète, challenge these ideas by using sounds not widely considered as musical, beautiful or harmonious, like randomly produced electronic distortion, feedback, static, cacophony, and sounds produced using compositional processes which utilize indeterminacy.",
"title": ""
},
{
"paragraph_id": 2,
"text": "An often-cited example of the dilemma in defining music is the work 4′33″ (1952) by the American composer John Cage (1912–1992). The written score has three movements and directs the performer(s) to appear on stage, indicate by gesture or other means when the piece begins, then make no sound throughout the duration of the piece, marking sections and the end by gesture. The audience hears only whatever ambient sounds may occur in the room. Some argue that 4′33″ is not music because, among other reasons, it contains no sounds that are conventionally considered \"musical\" and the composer and performer(s) exert no control over the organization of the sounds heard. Others argue it is music because the conventional definitions of musical sounds are unnecessarily and arbitrarily limited, and control over the organization of the sounds is achieved by the composer and performer(s) through their gestures that divide what is heard into specific sections and a comprehensible form.",
"title": ""
},
{
"paragraph_id": 3,
"text": "Because of differing fundamental concepts of music, the languages of many cultures do not contain a word that can be accurately translated as \"music\" as that word is generally understood by Western cultures. Inuit and most North American Indian languages do not have a general term for music. Among the Aztecs, the ancient Mexican theory of rhetoric, poetry, dance, and instrumental music used the Nahuatl term In xochitl-in kwikatl to refer to a complex mix of music and other poetic verbal and non-verbal elements, and reserved the word Kwikakayotl (or cuicacayotl) only for the sung expressions. There is no term for music in Nigerian languages Tiv, Yoruba, Igbo, Efik, Birom, Hausa, Idoma, Eggon or Jarawa. Many other languages have terms which only partly cover what Western culture typically means by the term music.() The Mapuche of Argentina do not have a word for music, but they do have words for instrumental versus improvised forms (kantun), European and non-Mapuche music (kantun winka), ceremonial songs (öl), and tayil.",
"title": "Concepts of music"
},
{
"paragraph_id": 4,
"text": "While some languages in West Africa have no term for music, some West African languages accept the general concepts of music.() Musiqi is the Persian word for the science and art of music, muzik being the sound and performance of music,() though some things European-influenced listeners would include, such as Quran chanting, are excluded.",
"title": "Concepts of music"
},
{
"paragraph_id": 5,
"text": "Ben Watson points out that Ludwig van Beethoven's Große Fuge (1825) \"sounded like noise\" to his audience at the time. Indeed, Beethoven's publishers persuaded him to remove it from its original setting as the last movement of a string quartet. He did so, replacing it with a sparkling Allegro. They subsequently published it separately. Musicologist Jean-Jacques Nattiez considers the difference between noise and music nebulous, explaining that \"The border between music and noise is always culturally defined—which implies that, even within a single society, this border does not always pass through the same place; in short, there is rarely a consensus ... By all accounts there is no single and intercultural universal concept defining what music might be\".",
"title": "Music vs. noise"
},
{
"paragraph_id": 6,
"text": "An often-cited definition of music is that it is \"organized sound\", a term originally coined by modernist composer Edgard Varèse in reference to his own musical aesthetic. Varèse's concept of music as \"organized sound\" fits into his vision of \"sound as living matter\" and of \"musical space as open rather than bounded\". He conceived the elements of his music in terms of \"sound-masses\", likening their organization to the natural phenomenon of crystallization. Varèse thought that \"to stubbornly conditioned ears, anything new in music has always been called noise\", and he posed the question, \"what is music but organized noises?\"",
"title": "Definitions"
},
{
"paragraph_id": 7,
"text": "The fifteenth edition of the Encyclopædia Britannica states that \"while there are no sounds that can be described as inherently unmusical, musicians in each culture have tended to restrict the range of sounds they will admit.\" A human organizing element is often felt to be implicit in music (sounds produced by non-human agents, such as waterfalls or birds, are often described as \"musical\", but perhaps less often as \"music\"). The composer R. Murray states that the sound of classical music \"has decays; it is granular; it has attacks; it fluctuates, swollen with impurities—and all this creates a musicality that comes before any 'cultural' musicality.\" However, in the view of semiologist Jean-Jacques Nattiez, \"just as music is whatever people choose to recognize as such, noise is whatever is recognized as disturbing, unpleasant, or both\". (See \"music as social construct\" below.)",
"title": "Definitions"
},
{
"paragraph_id": 8,
"text": "Levi R. Bryant defines music not as a language, but as a marked-based, problem-solving method, comparable to mathematics.",
"title": "Definitions"
},
{
"paragraph_id": 9,
"text": "Most definitions of music include a reference to sound and a list of universals of music can be generated by stating the elements (or aspects) of sound: pitch, timbre, loudness, duration, spatial location and texture.). However, in terms more specifically relating to music: following Wittgenstein, cognitive psychologist Eleanor Rosch proposes that categories are not clean cut but that something may be more or less a member of a category. As such the search for musical universals would fail and would not provide one with a valid definition. This is primarily because other cultures have different understandings in relation to the sounds that English-language writers refer to as music.",
"title": "Definitions"
},
{
"paragraph_id": 10,
"text": "Many people do, however, share a general idea of music. The Websters definition of music is a typical example: \"the science or art of ordering tones or sounds in succession, in combination, and in temporal relationships to produce a composition having unity and continuity\" (Webster's Collegiate Dictionary, online edition).",
"title": "Definitions"
},
{
"paragraph_id": 11,
"text": "This approach to the definition focuses not on the construction but on the experience of music. An extreme statement of the position has been articulated by the Italian composer Luciano Berio: \"Music is everything that one listens to with the intention of listening to music\". This approach permits the boundary between music and noise to change over time as the conventions of musical interpretation evolve within a culture, to be different in different cultures at any given moment, and to vary from person to person according to their experience and proclivities. It is further consistent with the subjective reality that even what would commonly be considered music is experienced as non-music if the mind is concentrating on other matters and thus not perceiving the sound's essence as music.",
"title": "Definitions"
},
{
"paragraph_id": 12,
"text": "In his 1983 book, Music as Heard, which sets out from the phenomenological position of Husserl, Merleau-Ponty, and Ricœur, Thomas Clifton defines music as \"an ordered arrangement of sounds and silences whose meaning is presentative rather than denotative ... This definition distinguishes music, as an end in itself, from compositional technique, and from sounds as purely physical objects.\" More precisely, \"music is the actualization of the possibility of any sound whatever to present to some human being a meaning which he experiences with his body—that is to say, with his mind, his feelings, his senses, his will, and his metabolism\". It is therefore \"a certain reciprocal relation established between a person, his behavior, and a sounding object\".",
"title": "Specific definitions"
},
{
"paragraph_id": 13,
"text": "Clifton accordingly differentiates music from non-music on the basis of the human behavior involved, rather than on either the nature of compositional technique or of sounds as purely physical objects. Consequently, the distinction becomes a question of what is meant by musical behavior: \"a musically behaving person is one whose very being is absorbed in the significance of the sounds being experienced.\" However, \"It is not altogether accurate to say that this person is listening to the sounds. First, the person is doing more than listening: he is perceiving, interpreting, judging, and feeling. Second, the preposition 'to' puts too much stress on the sounds as such. Thus, the musically behaving person experiences musical significance by means of, or through, the sounds\".",
"title": "Specific definitions"
},
{
"paragraph_id": 14,
"text": "In this framework, Clifton finds that there are two things that separate music from non-music: (1) musical meaning is presentative, and (2) music and non-music are distinguished in the idea of personal involvement. \"It is the notion of personal involvement which lends significance to the word ordered in this definition of music\". This is not to be understood, however, as a sanctification of extreme relativism, since \"it is precisely the 'subjective' aspect of experience which lured many writers earlier in this century down the path of sheer opinion-mongering. Later on this trend was reversed by a renewed interest in 'objective,' scientific, or otherwise non-introspective musical analysis. But we have good reason to believe that a musical experience is not a purely private thing, like seeing pink elephants, and that reporting about such an experience need not be subjective in the sense of it being a mere matter of opinion\".",
"title": "Specific definitions"
},
{
"paragraph_id": 15,
"text": "Clifton's task, then, is to describe musical experience and the objects of this experience which, together, are called \"phenomena\", and the activity of describing phenomena is called \"phenomenology\". It is important to stress that this definition of music says nothing about aesthetic standards.",
"title": "Specific definitions"
},
{
"paragraph_id": 16,
"text": "Music is not a fact or a thing in the world, but a meaning constituted by human beings. ... To talk about such experience in a meaningful way demands several things. First, we have to be willing to let the composition speak to us, to let it reveal its own order and significance. ... Second, we have to be willing to question our assumptions about the nature and role of musical materials. ... Last, and perhaps most important, we have to be ready to admit that describing a meaningful experience is itself meaningful.",
"title": "Specific definitions"
},
{
"paragraph_id": 17,
"text": "\"Music, often an art/entertainment, is a total social fact whose definitions vary according to era and culture\", according to Jean. It is often contrasted with noise. According to musicologist Jean-Jacques Nattiez: \"The border between music and noise is always culturally defined—which implies that, even within a single society, this border does not always pass through the same place; in short, there is rarely a consensus ... By all accounts there is no single and intercultural universal concept defining what music might be\". Given the above demonstration that \"there is no limit to the number or the genre of variables that might intervene in a definition of the musical\", an organization of definitions and elements is necessary.",
"title": "Specific definitions"
},
{
"paragraph_id": 18,
"text": "Nattiez (1990, 17) describes definitions according to a tripartite semiological scheme similar to the following:",
"title": "Specific definitions"
},
{
"paragraph_id": 19,
"text": "There are three levels of description, the poietic, the neutral, and the esthesic:",
"title": "Specific definitions"
},
{
"paragraph_id": 20,
"text": "Table describing types of definitions of music:",
"title": "Specific definitions"
},
{
"paragraph_id": 21,
"text": "Because of this range of definitions, the study of music comes in a wide variety of forms. There is the study of sound and vibration or acoustics, the cognitive study of music, the study of music theory and performance practice or music theory and ethnomusicology and the study of the reception and history of music, generally called musicology.",
"title": "Specific definitions"
},
{
"paragraph_id": 22,
"text": "Composer Iannis Xenakis in \"Towards a Metamusic\" (chapter 7 of Formalized Music) defined music in the following way:",
"title": "Specific definitions"
},
{
"paragraph_id": 23,
"text": "Sources",
"title": "References"
}
] | A definition of music endeavors to give an accurate and concise explanation of music's basic attributes or essential nature and it involves a process of defining what is meant by the term music. Many authorities have suggested definitions, but defining music turns out to be more difficult than might first be imagined, and there is ongoing debate. A number of explanations start with the notion of music as organized sound, but they also highlight that this is perhaps too broad a definition and cite examples of organized sound that are not defined as music, such as human speech and sounds found in both natural and industrial environments. The problem of defining music is further complicated by the influence of culture in music cognition. The Concise Oxford Dictionary defines music as "the art of combining vocal or instrumental sounds to produce beauty of form, harmony, and expression of emotion". However, some music genres, such as noise music and musique concrète, challenge these ideas by using sounds not widely considered as musical, beautiful or harmonious, like randomly produced electronic distortion, feedback, static, cacophony, and sounds produced using compositional processes which utilize indeterminacy. An often-cited example of the dilemma in defining music is the work 4′33″ (1952) by the American composer John Cage (1912–1992). The written score has three movements and directs the performer(s) to appear on stage, indicate by gesture or other means when the piece begins, then make no sound throughout the duration of the piece, marking sections and the end by gesture. The audience hears only whatever ambient sounds may occur in the room. Some argue that 4′33″ is not music because, among other reasons, it contains no sounds that are conventionally considered "musical" and the composer and performer(s) exert no control over the organization of the sounds heard. Others argue it is music because the conventional definitions of musical sounds are unnecessarily and arbitrarily limited, and control over the organization of the sounds is achieved by the composer and performer(s) through their gestures that divide what is heard into specific sections and a comprehensible form. | 2001-11-05T09:52:36Z | 2023-11-12T00:53:07Z | [
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] | https://en.wikipedia.org/wiki/Definition_of_music |
8,253 | Dayton, Ohio | Dayton (/ˈdeɪtən/ ) is a city in and the county seat of Montgomery County, Ohio, United States. A small part of the city extends into Greene County. As of the 2020 census, the city proper had a population of 137,644, making it the sixth-most populous city in Ohio. Dayton anchors the state's fourth-largest metropolitan area, the Dayton metropolitan area, which had 814,049 residents. Dayton is located within Ohio's Miami Valley region, 50 miles (80 km) north of Cincinnati and 60 miles (97 km) west of Columbus. It is a principal city of the Dayton–Springfield–Sidney combined statistical area, home to a population of 1,086,512.
Dayton was founded in 1796 along the Great Miami River and named after Jonathan Dayton, a Founding Father who owned a significant amount of land in the area. It grew in the 19th century as a canal town and was home to many patents and inventors, most notably the Wright brothers, who developed the first successful motor-operated airplane. It later developed an industrialized economy and was home to the Dayton Project, a branch of the larger Manhattan Project, to develop polonium triggers used in early atomic bombs. With the decline of heavy manufacturing in the late 20th century, Dayton's businesses have diversified into a service economy.
Ohio's borders are within 500 miles (800 km) of roughly 60 percent of the country's population and manufacturing infrastructure, making Dayton a logistics hub. The city is home to Wright-Patterson Air Force Base, a significant contributor to research and development in the industrial, aeronautical, and astronautical engineering fields. Along with defense and aerospace, healthcare accounts for much of the Dayton area's economy. Significant institutions in Dayton include the Air Force Institute of Technology, Carillon Historical Park, Dayton Art Institute, Dayton Performing Arts Alliance, National Museum of the United States Air Force, and University of Dayton.
Dayton was founded on April 1, 1796, by 12 settlers known as the Thompson Party. They traveled in March from Cincinnati up the Great Miami River by pirogue and landed at what is now St. Clair Street, where they found two small camps of Native Americans. Among the Thompson Party was Benjamin Van Cleve, whose memoirs provide insights into the Ohio Valley's history. Two other groups traveling overland arrived several days later. The oldest surviving building is Newcom Tavern, which was used for various purposes, including housing Dayton's first church, which is still in existence.
In 1797, Daniel C. Cooper laid out Mad River Road, the first overland connection between Cincinnati and Dayton, opening the "Mad River Country" to settlement. Ohio was admitted into the Union in 1803, and the village of Dayton was incorporated in 1805 and chartered as a city in 1841. The city was named after Jonathan Dayton, a captain in the American Revolutionary War who signed the U.S. Constitution and owned a significant amount of land in the area. In 1827, construction on the Dayton–Cincinnati canal began, which provided a better way to transport goods from Dayton to Cincinnati and contributed significantly to Dayton's economic growth during the 1800s.
Innovation led to business growth in the region. In 1884, John Henry Patterson acquired James Ritty's National Manufacturing Company along with his cash register patents and formed the National Cash Register Company (NCR). The company manufactured the first mechanical cash registers and played a crucial role in the shaping of Dayton's reputation as an epicenter for manufacturing in the early 1900s. In 1906, Charles F. Kettering, a leading engineer at the company, helped develop the first electric cash register, which propelled NCR into the national spotlight. NCR also helped develop the US Navy Bombe, a code-breaking machine that helped crack the Enigma machine cipher during World War II.
Dayton has been the home for many patents and inventions since the 1870s. According to the National Park Service, citing information from the U.S. Patent Office, Dayton had granted more patents per capita than any other U.S. city in 1890 and ranked fifth in the nation as early as 1870. The Wright brothers, inventors of the airplane, and Charles F. Kettering, world-renowned for his numerous inventions, hailed from Dayton. The city was also home to James Ritty's Incorruptible Cashier, the first mechanical cash register, and Arthur E. Morgan's hydraulic jump, a flood prevention mechanism that helped pioneer hydraulic engineering. Paul Laurence Dunbar, an African-American poet and novelist, penned his most famous works in the late 19th century and became an integral part of the city's history.
Powered aviation began in Dayton. Orville and Wilbur Wright were the first to construct and demonstrate powered flight. Although the first flight was in Kitty Hawk, North Carolina, their Wright Flyer was built in and returned to Dayton for improvements and further flights at Huffman Field, a cow pasture eight miles (13 km) northeast of Dayton, near the current Wright-Patterson Air Force Base.
When the government tried to move development to Langley field in southern Virginia, six Dayton businessmen including Edward A. Deeds, formed the Dayton-Wright Airplane Company in Moraine and established a flying field. Deeds also opened a field to the north in the flood plain of the Great Miami River between the confluences of that river, the Stillwater River, and the Mad River, near downtown Dayton. Later named McCook Field for Alexander McDowell McCook, an American Civil War general, this became the Army Signal Corps' primary aviation research and training location. Wilbur Wright also purchased land near Huffman prairie to continue their research.
During World War I, the Army purchased 40 acres adjacent to Huffman Prairie for the Fairfield Aviation General Supply Depot. As airplanes developed more capability, they needed more runway space than McCook could offer, and a new location was sought. The Patterson family formed the Dayton Air Service Committee, Inc which held a campaign that raised $425,000 in two days and purchased 4,520.47 acres (18.2937 km) northeast of Dayton, including Wilbur Wright Field and the Huffman Prairie Flying Field. Wright Field was "formally dedicated" on October 12, 1927. After World War II, Wright Field and the adjacent Patterson Field, Dayton Army Air Field, and Clinton Army Air Field were merged as the Headquarters, Air Force Technical Base. On January 13, 1948, the facility was renamed Wright-Patterson Air Force Base.
A catastrophic flood in March 1913, known as the Great Dayton Flood, led to the creation of the Miami Conservancy District, a series of dams as well as hydraulic pumps installed around Dayton, in 1914.
Like other cities across the country, Dayton was heavily involved in the war effort during World War II. Several locations around the city hosted the Dayton Project, a branch of the larger Manhattan Project, to develop polonium triggers used in early atomic bombs. The war efforts led to a manufacturing boom throughout the city, including high demand for housing and other services. At one point, emergency housing was put into place due to a housing shortage in the region, much of which is still in use today.
Alan Turing is widely considered to be the father of theoretical computer science and artificial intelligence. He visited the National Cash Register (NCR) company in Dayton in December 1942. He was able to show that it was not necessary to build 336 Bombes, so the initial order was scaled down to 96 machines to decipher German Enigma-machine-encrypted secret messages during World War II.
Between the 1940s and the 1970s, the city saw significant growth in suburban areas from population migration. Veterans were returning from military service in large numbers seeking industrial and manufacturing jobs, a part of the local industry that was expanding rapidly. Advancements in architecture also contributed to the suburban boom. New, modernized shopping centers and the Interstate Highway System allowed workers to commute greater distances and families to live further from the downtown area. More than 127,000 homes were built in Montgomery County during the 1950s.
During this time, the city was the site of several race riots, including one in 1955 following the murder of Emmett Till, the 1966 Dayton race riot, two in 1967 (following a speech by civil rights activist H. Rap Brown and another following the police killing of an African American man), and one in 1968 as part of the nationwide King assassination riots.
Since the 1980s, however, Dayton's population has declined, mainly due to the loss of manufacturing jobs and decentralization of metropolitan areas, as well as the national housing crisis that began in 2008. While much of the state has suffered for similar reasons, the impact on Dayton has been greater than most. Dayton had the third-greatest percentage loss of population in the state since the 1980s, behind Cleveland and Youngstown. Despite this, Dayton has begun diversifying its workforce from manufacturing into other growing sectors such as healthcare and education.
In 1995, the Dayton Agreement, a peace accord between the parties to the hostilities of the conflict in Bosnia-Herzegovina and the former Yugoslavia, was negotiated at Wright-Patterson Air Force Base, near Fairborn, Ohio, from November 1 to 21.
Richard Holbrooke wrote about these events in his memoirs:
There was also a real Dayton out there, a charming Ohio city, famous as the birthplace of the Wright brothers. Its citizens energized us from the outset. Unlike the population of, say, New York City, Geneva or Washington, which would scarcely notice another conference, Daytonians were proud to be part of history. Large signs at the commercial airport hailed Dayton as the "temporary center of international peace." The local newspapers and television stations covered the story from every angle, drawing the people deeper into the proceedings. When we ventured into a restaurant or a shopping center downtown, people crowded around, saying that they were praying for us. Warren Christopher was given at least one standing ovation in a restaurant. Families on the airbase placed "candles of peace" in their front windows, and people gathered in peace vigils outside the base. One day they formed a "peace chain," although it was not large enough to surround the sprawling eight-thousand-acre base. Ohio's famous ethnic diversity was on display.
Downtown expansion that began in the 2000s has helped revitalize the city and encourage growth. Day Air Ballpark, home of the Dayton Dragons, was built in 2000. The highly successful minor league baseball team has been an integral part of Dayton's culture. In 2001, the city's public park system, Five Rivers MetroParks, built RiverScape MetroPark, an outdoor entertainment venue that attracts more than 400,000 visitors each year. A new performance arts theater, the Schuster Center, opened in 2003. A large health network in the region, Premier Health Partners, expanded its Miami Valley Hospital with a 12-story tower addition.
In 2010, the Downtown Dayton Partnership, in cooperation with the City of Dayton and community leaders, introduced the Greater Downtown Dayton Plan. It focuses on job creation and retention, infrastructure improvements, housing, recreation, and collaboration. The plan is to be implemented through the year 2020.
Dayton is known as the "Gem City". The nickname's origin is uncertain, but several theories exist. In the early 19th century, a well-known racehorse named Gem hailed from Dayton. In 1845, an article published in the Cincinnati Daily Chronicle by an author known as T stated:
In a small bend of the Great Miami River, with canals on the east and south, it can be fairly said, without infringing on the rights of others, that Dayton is the gem of all our interior towns. It possesses wealth, refinement, enterprise, and a beautiful country, beautifully developed.
In the late 1840s, Major William D. Bickham of the Dayton Journal began a campaign to nickname Dayton the "Gem City." The name was adopted by the city's Board of Trade several years later. Paul Laurence Dunbar referred to the nickname in his poem, "Toast to Dayton", as noted in the following excerpt:
She shall ever claim our duty, For she shines—the brightest gem That has ever decked with beauty Dear Ohio's diadem.
Dayton also plays a role in a nickname given to the state of Ohio, "Birthplace of Aviation." Dayton is the hometown of the Wright brothers, aviation pioneers who are credited with inventing and building the first practical airplane in history. After their first manned flights in Kitty Hawk, North Carolina, which they had chosen due to its ideal weather and climate conditions, the Wrights returned to Dayton and continued testing at nearby Huffman Prairie.
Additionally, Dayton is colloquially referred to as "Little Detroit". This nickname comes from Dayton's prominence as a Midwestern manufacturing center.
According to the United States Census Bureau, the city has a total area of 56.50 square miles (146.33 km), of which 55.65 square miles (144.13 km) is land and 0.85 square miles (2.20 km) is water.
Dayton's climate features warm, muggy summers and cold, dry winters, and is classified as a humid continental climate (Köppen Dfa). Unless otherwise noted, all normal figures quoted within the text below are from the official climatology station, Dayton International Airport, at an elevation of 1,000 ft (304.8 m) about 10 mi (16 km) to the north of downtown Dayton, which lies within the valley of the Miami River; thus temperatures there are typically cooler than in downtown.
At the airport, monthly mean temperatures range from 27.5 °F (−2.5 °C) in January to 74.1 °F (23.4 °C) in July. The highest temperature ever recorded in Dayton was 108 °F (42 °C) on July 22, 1901, and the coldest was −28 °F (−33 °C) on February 13 during the Great Blizzard of 1899. On average, there are 14 days of 90 °F (32 °C)+ highs and 4.5 nights of sub-0 °F (−18 °C) lows annually. Snow is moderate, with a normal seasonal accumulation of 23.3 in (59 cm), usually occurring from November to March, occasionally April, and rarely October. Precipitation averages 41.1 inches (1,040 mm) annually, with total rainfall peaking in May.
Dayton is subject to severe weather typical of the Midwestern United States. Tornadoes are possible from the spring to the fall. Floods, blizzards, and severe thunderstorms can also occur.
On Memorial Day of 2019, Dayton suffered extensive property damage and one death during a tornado outbreak, in which a total of 15 tornadoes touched down in the Dayton area. Although some of the tornadoes were only EF0 and remained on the ground for less than a mile, one was an EF4 measuring a half-mile-wide (805 meters), which tore through the communities of Brookville, Trotwood, Dayton, and Riverside. Several streets were closed, including portions of I-75 and North Dixie Street. 64,000 residents lost power and much of the region's water supply was cut off.
The Dayton Audubon Society is the National Audubon Society's local chapter. The Dayton chapter manages local activities contributing to the annual, hemisphere-wide Christmas Bird Count. The Chapter began participation in the National Count in 1924. The local Count was initially coordinated by Ben Blincoe, who was succeeded by Jim Hill in 1970. In the mid-1960s, the freezing of Lake Erie and associated marshlands led species of waterfowl to appear in the Dayton-area, where surface waters remained unfrozen. Nine varieties of birds have been observed every year in the Dayton area: downy woodpecker, Carolina chickadee, tufted titmouse, brown creeper, cardinal, junco, tree sparrow, song sparrow and crow.
Unlike many Midwestern cities its age, Dayton has very broad and straight downtown streets (generally two or three full lanes in each direction) that improved access to the downtown even after the automobile became popular. The main reason for the broad streets was that Dayton was a marketing and shipping center from its beginning; streets were broad to enable wagons drawn by teams of three to four pairs of oxen to turn around. Also, some of today's streets were once barge canals flanked by draw-paths.
A courthouse building was built in downtown Dayton in 1888 to supplement Dayton's original Neoclassical courthouse, which still stands. This second, "new" courthouse has since been replaced with new facilities as well as a park. The Old Court House has been a favored political campaign stop. On September 17, 1859, Abraham Lincoln delivered an address on its steps. Eight other presidents have visited the courthouse, either as presidents or during presidential campaigns: Andrew Johnson, James Garfield, John F. Kennedy, Lyndon B. Johnson, Richard Nixon, Gerald Ford, Ronald Reagan, and Bill Clinton.
The Dayton Arcade, which opened on March 3, 1904, was built in the hopes of replacing open-air markets throughout the city. Throughout the decades, the Arcade has gone through many transformations but has retained its charm. Some of its main features include a Flemish facade at the Third Street entrance, a glass dome above the Arcade rotunda, and a chateau roof line above the Third Street facade. The Dayton Arcade is currently under renovations with no official completion date set.
In 2009, the CareSource Management Group finished construction of a $55 million corporate headquarters in downtown Dayton. The 300,000-square-foot (28,000 m), 10-story building was downtown's first new office tower in more than a decade.
Dayton's two tallest buildings are the Kettering Tower at 408 ft (124 m) and the KeyBank Tower at 385 ft (117 m). Kettering Tower was originally Winters Tower, the headquarters of Winters Bank. The building was renamed after Virginia Kettering when Winters was merged into Bank One. KeyBank Tower was known as the MeadWestvaco Tower before KeyBank gained naming rights to the building in 2008.
Ted Rall said in 2015 that over the last five decades Dayton has been demolishing some of its architecturally significant buildings to reduce the city's rental vacancy rate and thus increase the occupancy rate.
Dayton's ten historic neighborhoods—Oregon District, Wright Dunbar, Dayton View, Grafton Hill, McPherson Town, Webster Station, Huffman, Kenilworth, St. Anne's Hill, and South Park—feature mostly single-family houses and mansions in the Neoclassical, Jacobethan, Tudor Revival, English Gothic, Chateauesque, Craftsman, Queen Anne, Georgian Revival, Colonial Revival, Renaissance Revival Architecture, Shingle Style Architecture, Prairie, Mission Revival, Eastlake/Italianate, American Foursquare, and Federal styles. Downtown Dayton is also a large area that encompasses several neighborhoods itself and has seen a recent uplift and revival.
Dayton's suburbs with a population of 10,000 or more include Beavercreek, Centerville, Clayton, Englewood, Fairborn, Harrison Township, Huber Heights, Kettering, Miami Township, Miamisburg, Oakwood, Riverside, Springboro, Trotwood, Vandalia, Washington Township, West Carrollton, and Xenia.
In the federal government's National Urban Policy and New Community Development Act of 1970, funding was provided for thirteen "new towns" or planned cities throughout the country. One location was set to become a suburb of Dayton and was known variously as Brookwood or Newfields. The goal was to have an entirely new suburb that would eventually house about 35,000 residents. The new town was to be located between Trotwood and Brookville, and modeled on the ideas of Ian McHarg. The project was abandoned in 1978 and most of the land became Sycamore State Park.
Dayton's population declined significantly from a peak of 262,332 residents in 1960 to only 141,759 in 2010. This was in part due to the slowdown of the region's manufacturing and the growth of Dayton's affluent suburbs including Oakwood, Englewood, Beavercreek, Springboro, Miamisburg, Kettering, and Centerville. The city's most populous ethnic group, white, declined from 78.1% in 1960 to 51.7% by 2010. Recent census estimates show a population decline since 2010.
As of the 2000 census, the median income for a household in the city was $27,523, and the median income for a family was $34,978. Males had a median income of $30,816 versus $24,937 for females. The per capita income for the city was $34,724. About 18.2% of families and 23.0% of the population were below the poverty line, including 32.0% of those under age 18 and 15.3% of those age 65 or over.
As of the 2010 census, there were 141,759 people, 58,404 households, and 31,064 families residing in the city. The population density was 2,543.2 inhabitants per square mile (981.9/km). There were 74,065 housing units at an average density of 1,330.9 per square mile (513.9/km). The racial makeup of the city was 51.7% White, 42.9% African American, 0.3% Native American, 0.9% Asian, 1.3% from other races, and 2.9% from two or more races. Hispanic or Latino of any race were 3.0% of the population.
There were 58,404 households, of which 28.3% had children under the age of 18 living with them, 25.9% were married couples living together, 21.4% had a female householder with no husband present, 5.9% had a male householder with no wife present, and 46.8% were non-families. 38.8% of all households were made up of individuals, and 11.2% had someone living alone who was 65 years of age or older. The average household size was 2.26, and the average family size was 3.03.
The median age in the city was 34.4 years. 22.9% of residents were under the age of 18; 14.2% were between the ages of 18 and 24; 25.3% were from 25 to 44; 25.8% were from 45 to 64, and 11.8% were 65 years of age or older. The gender makeup of the city was 48.7% male and 51.3% female.
Dayton's crime declined between 2003 and 2008 in key categories according to FBI Uniform Crime Reports and Dayton Police Department data. In 2009, crime continued to fall in the city of Dayton. Crime in the categories of forcible rape, aggravated assault, property crime, motor vehicle theft, robbery, burglary, theft and arson all showed declines for 2009. Overall, crime in Dayton dropped 40% over the previous year. The Dayton Police Department reported a total of 39 murders in 2016, which marked a 39.3% increase in homicides from 2015.
John Dillinger, a bank robber during the early 1930s, was captured and arrested by Dayton city police while visiting his girlfriend at a high-class boarding house in downtown Dayton.
On August 4, 2019, a mass shooting took place in Dayton. Ten people were killed, including the perpetrator; and twenty-seven were injured.
Dayton's economy is relatively diversified and vital to the overall economy of the state of Ohio. In 2008 and 2009, Site Selection magazine ranked Dayton the #1 medium-sized metropolitan area in the U.S. for economic development. Dayton is also among the top 100 metropolitan areas in both exports and export-related jobs, ranked 16 and 14 respectively by the Brookings Institution. The 2010 report placed the value of exports at $4.7 billion and the number of export-related jobs at 44,133. The Dayton Metropolitan Statistical Area ranks 4th in Ohio's Gross Domestic Product with a 2008 industry total of $33.78 billion. Additionally, Dayton ranks third among 11 major metropolitan areas in Ohio for exports to foreign countries. The Dayton Development Coalition is attempting to leverage the region's large water capacity, estimated to be 1.5 trillion gallons of renewable water aquifers, to attract new businesses. Moody's Investment Services revised Dayton's bond rating from A1 to the stronger rating of Aa2 as part of its global recalibration process. Standard & Poor's upgraded Dayton's rating from A+ to AA− in the summer of 2009.
Bloomberg Businessweek ranked Dayton in 2010 as one of the best places in the U.S. for college graduates looking for a job. Companies such as Reynolds and Reynolds, Stratacache, CareSource, DP&L (soon AES inc), LexisNexis, Kettering Health Network, Premier Health Partners, and Standard Register have their headquarters in Dayton. It is also the former home of the Speedwell Motor Car Company, MeadWestvaco (formerly known as the Mead Paper Company), and NCR. NCR was headquartered in Dayton for over 125 years and was a major innovator in computer technology.
The Dayton region gave birth to aviation and is known for its high concentration of aerospace and aviation technology. In 2009, Governor Ted Strickland designated Dayton as Ohio's aerospace innovation hub, the state's first such technology hub. Two major United States research and development organizations have leveraged Dayton's historical leadership in aviation and maintain their headquarters in the area: The National Air and Space Intelligence Center (NASIC) and the Air Force Research Laboratory (AFRL). Both have their headquarters at Wright-Patterson Air Force Base.
Several research organizations support NASIC, AFRL, and the Dayton community. The Advanced Technical Intelligence Center is a confederation of government, academic, and industry partners. The University of Dayton Research Institute (UDRI) is led by the University of Dayton. The Cognitive Technologies Division (CTD) of Applied Research Associates, Inc., which carries out human-centered research and design, is headquartered in the Dayton suburb of Fairborn. The city of Dayton has started Tech Town, a development project to attract technology-based firms and revitalize the downtown area. Tech Town is home to the world's first RFID business incubator. The University of Dayton–led Institute for Development & Commercialization of Sensor Technologies (IDCAST) at TechTown is a center for remote sensing and sensing technology. It is one of Dayton's technology business incubators housed in The Entrepreneurs Center building.
The Kettering Health Network and Premier Health Partners have a major role on the Dayton area's economy. Hospitals in the Greater Dayton area have an estimated combined employment of nearly 32,000 and a yearly economic impact of $6.8 billion. In addition, several Dayton area hospitals consistently earn top national ranking and recognition including the U.S. News & World Report's list of "America's Best Hospitals" as well as many of HealthGrades top ratings. The most notable hospitals are Miami Valley Hospital and Kettering Medical Center.
The Dayton region has several key institutes and centers for health care. The Center for Tissue Regeneration and Engineering at Dayton focuses on the science and development of human tissue regeneration. The National Center for Medical Readiness (NCMR) is also in the Dayton area. The center includes Calamityville, which is a disaster training facility. Over five years, Calamityville is estimated to have a regional economic impact of $374 million. Also, the Neurological Institute at Miami Valley Hospital is an institute focused on the diagnosis, treatment, and research of neurological disorders.
According to the city's 2019 Comprehensive Annual Financial Report, the top employers in the city proper are:
The Dayton Region ranked within the top 10% in the nation in arts and culture. In a 2012 readers' poll by American Style magazine, Dayton ranked #2 in the country among mid-size cities as an arts destination, ranking higher than larger cities such as Atlanta, St. Louis, and Cincinnati. Dayton is the home of the Dayton Art Institute.
The Benjamin and Marian Schuster Performing Arts Center in downtown Dayton is a world-class performing arts center and the home venue of the Dayton Philharmonic Orchestra, Dayton Opera, and the Dayton Ballet. In addition to philharmonic and opera performances, the Schuster Center hosts concerts, lectures, and traveling Broadway shows, and is a popular spot for weddings and other events. The historic Victoria Theatre in downtown Dayton hosts concerts, traveling Broadway shows, ballet, a summertime classic film series, and more. The Loft Theatre, also downtown, is the home of the Human Race Theatre Company. The Dayton Playhouse, in West Dayton, is the site of numerous plays and theatrical productions. Between 1957 and 1995, the Kenley Players presented live theater productions in Dayton. In 2013, John Kenley was inducted into the Dayton Theatre Hall of Fame. Dayton is also home to the Winter Guard International world finals, hosting finals for winter guard, indoor percussion, and indoor winds.
Dayton is the home to several ballet companies including:
Front Street, the largest artists' collective in Dayton, is housed in three industrial buildings on East Second Street.
The Vectren Dayton Air Show is an annual air show that takes place at the Dayton International Airport. The Vectren Dayton Airshow is one of the largest air shows in the United States.
The Dayton area is served by Five Rivers MetroParks, encompassing 14,161 acres (5,731 ha) over 23 facilities for year-round recreation, education, and conservation. In cooperation with the Miami Conservancy District, the MetroParks maintains over 70 miles (113 km) of paved, multi-use scenic trails that connect Montgomery County with Greene, Miami, Warren, and Butler counties.
Dayton was home to a thriving funk music scene from the 1970s to the early 1980s, that included bands such as Ohio Players, Roger Troutman & Zapp, Lakeside, Sun, Dayton, Heatwave, and Slave.
Dayton was also the birthplace to several influential indie and punk bands such as The Breeders, Guided by Voices, and Brainiac.
From 1996 to 1998, Dayton hosted the National Folk Festival. Since then, the annual Cityfolk Festival has continued to bring folk, ethnic, and world music and arts to Dayton. The Five Rivers MetroParks also owns and operates the PNC Second Street Market near downtown Dayton.
The Dayton area hosts several arenas and venues. South of Dayton in Kettering is the Fraze Pavilion, whose notable performances have included the Backstreet Boys, Boston, and Steve Miller Band. South of downtown, on the banks of the Great Miami River, is the University of Dayton Arena, home venue for the University of Dayton Flyers basketball teams and the location of various other events and concerts. It also hosts the Winter Guard International championships, at which hundreds of percussion and color guard ensembles from around the world compete. In addition, the Dayton Amateur Radio Association hosts the annual Dayton Hamvention, North America's largest hamfest, at the Greene County Fairgrounds in nearby Xenia. The Nutter Center, which is just east of Dayton in the suburb of Fairborn, is the home arena for athletics of Wright State University and the former Dayton Bombers hockey team. This venue is used for many concerts, community events, and various national traveling shows and performances.
The Oregon District is a historic residential and commercial district in southeast downtown Dayton. The district is populated with art galleries, specialty shops, pubs, nightclubs, and coffee houses.
The city of Dayton is also host to yearly festivals, such as the Dayton Celtic Festival, the Dayton Blues Festival, Dayton Music Fest, Urban Nights, Women in Jazz, the African American and Cultural Festival, and the Dayton Reggae Fest.
The city's fine dining restaurants include The Pine Club, a nationally known steakhouse.
Dayton is home to a variety of pizza chains that have become woven into local culture, the most notable of which are Cassano's and Marion's Piazza, both of which produce Dayton-style pizza, which has a thin, crisp, salty crust dusted on the bottom with cornmeal and topped with a thin layer of thick unsweetened sauce. Cheese and other topping ingredients are heavily distributed and spread edge-to-edge with no outer rim of crust, and the finished pizza is cut into bite-size squares.
Notable Dayton-based restaurant chains include Hot Head Burritos.
In addition to restaurants, the city is also home to Esther Price Candies, a candy and chocolate company, and Mike-sells, the oldest potato chip company in the United States.
The city began developing a reputation for its number of breweries and craft beer venues by the late 2010s.
Many major religions are represented in Dayton. Christianity is represented in Dayton by dozens of denominations and their respective churches. Notable Dayton churches include the First Lutheran Church, Sacred Heart Church, and Ginghamsburg Church. Dayton's Muslim community is largely represented by the Islamic Society of Greater Dayton (ISGD), a Muslim community that includes a mosque on Josie Street. Dayton is also home to the United Theological Seminary, one of 13 seminaries affiliated with the United Methodist Church. Judaism is represented by Temple Israel. Hinduism is represented by the Hindu Temple of Dayton. Old North Dayton also has a number of Catholic churches built by immigrants from Lithuania, Poland, Hungary, and Germany.
Tourism also accounts for one out of every 14 private sector jobs in the county. Tourism in the Dayton region is led by the National Museum of the United States Air Force at Wright-Patterson Air Force Base, the largest and oldest military aviation museum in the world. The museum draws over 1.3 million visitors per year and is one of the most-visited tourist attractions in Ohio. The museum houses the National Aviation Hall of Fame.
Other museums also play significant roles in the tourism and economy of the Dayton area. The Dayton Art Institute, a museum of fine arts, owns collections containing more than 20,000 objects spanning 5,000 years of art and archaeological history. The Dayton Art Institute was rated one of the top 10 best art museums in the United States for children. The Boonshoft Museum of Discovery is a children's museum of science with numerous exhibits, one of which includes an indoor zoo with nearly 100 different animals.
There are also some notable historical museums in the region. The Dayton Aviation Heritage National Historical Park, operated by the National Park Service, commemorates the lives and achievements of Dayton natives Orville and Wilbur Wright and Paul Laurence Dunbar. The Wright brothers' famous Wright Flyer III aircraft is housed in a museum at Carillon Historical Park. Dayton is also home to America's Packard Museum, which contains many restored historical Packard vehicles. SunWatch Indian Village/Archaeological Park, a partially reconstructed 12th-century prehistoric American Indian village, is on the south end of Dayton; it is organized around a central plaza dominated by wood posts forming an astronomical calendar. The park includes a museum where visitors can learn about the Indian history of the Miami Valley.
Dayton was named National Geographic's outdoor adventure capital of the Midwest in 2019 due in large part to the metropolitan area's revitalized Five Rivers MetroPark, extensive bicycle and jogging trail system, urban green spaces, lakes and camping areas.
In cooperation with the Miami Conservancy District, Five Rivers MetroParks hosts 340 miles of paved trails, the largest network of paved off-street trails in the United States. The regional trail system represents over 35% of the 900 miles in Ohio's off-street trail network. In 2010, the city of Troy was named "bike friendly" by the League of American Bicyclists, which gave the city the organization's bronze designation. The honorable mention made Dayton one of two cities in Ohio to receive the award, the other being Columbus, and one of 15 cities nationwide.
The Dayton area is home to several minor league and semi pro teams, as well as NCAA Division I sports programs.
The Dayton Dragons professional baseball team is a Class A minor league affiliate for the Cincinnati Reds. The Dayton Dragons are the first (and only) team in minor league baseball history to sell out an entire season before it began and was voted as one of the top 10 hottest tickets to get in all of professional sports by Sports Illustrated. The Dayton Dragons 815 consecutive sellouts surpassed the NBA's Portland Trail Blazers for the longest sellout streak across all professional sports in the U.S.
The University of Dayton and Wright State University both host NCAA basketball. The University of Dayton Arena has hosted more games in the NCAA men's basketball tournament over its history than any other venue. UD Arena is also the site of the First Round games of the NCAA Tournament. In 2012, eight teams competed for the final four spots in the NCAA basketball tournament. Wright State University's NCAA men's basketball is the Wright State Raiders and the University of Dayton's NCAA men's basketball team is the Dayton Flyers.
The Dayton Gems were a minor league ice hockey team in the International Hockey League from 1964 to 1977, 1979 to 1980, and most recently 2009 to 2012. The Dayton Bombers were an ECHL ice hockey team from 1991 to 2009. They most recently played the North Division of the ECHL's American Conference. In June 2009, it was announced the Bombers would turn in their membership back to the league.
Despite the folding of the Bombers, hockey remained in Dayton as the Dayton Gems of the International Hockey League were formed in the fall of 2009 at Hara Arena. The Gems folded after the 2011–12 season. Shortly after the Gems folded, it was announced a new team, the Dayton Demonz, would begin play in 2012 in the Federal Hockey League (FHL). The Demonz folded in 2015 and were immediately replaced by the Dayton Demolition, also in the FHL. However, the Demolition would cease operations after only one season when Hara Arena decided to close due to financial difficulties.
Dayton hosted the first American Professional Football Association game (precursor to the NFL). The game was played at Triangle Park between the Dayton Triangles and the Columbus Panhandles on October 3, 1920, and is considered one of the first professional football games ever played. Football teams in the Dayton area include the Dayton Flyers and the Dayton Sharks.
The Dayton region is also known for the many golf courses and clubs that it hosts. The Miami Valley Golf Club, Moraine Country Club, NCR Country Club, and the Pipestone Golf Course are some of the more notable courses. Also, several PGA Championships have been held at area golf courses. The Miami Valley Golf Club hosted the 1957 PGA Championship, the Moraine Country Club hosted the 1945 PGA Championship, and the NCR Country club hosted the 1969 PGA Championship. Additionally, NCR CC hosted the 1986 U.S. Women's Open, the 2005 U.S. Senior Open, the 2013 State Team Championships and most recently the 2022 Senior Women's Open. Other notable courses include the Yankee Trace Golf Club, the Beavercreek Golf Club, Dayton Meadowbrook Country Club, Sycamore Creek Country Club, Heatherwoode Golf Club, Community Golf Course, and Kitty Hawk Golf Course.
The city of Dayton is the home to the Dayton Area Rugby Club which hosts their home games at the Dayton Rugby Grounds. As of 2018, the club fields two men's and one women's side for Rugby Union and several Rugby Sevens sides. The club also hosts the annual Gem City 7's tournament.
The Dayton City Commission is composed of the mayor and four city commissioners. Each city commission member is elected at-large on a non-partisan basis for four-year, overlapping terms. All policy items are decided by the city commission, which is empowered by the City Charter to pass ordinances and resolutions, adopt regulations, and appoint the city manager. The city manager is responsible for budgeting and implementing policies and initiatives. Dayton was the first large American city to adopt the city manager (Henry Matson Waite (engineer)), form of municipal government, in 1913.
Dayton Public Schools operates 34 schools that serve 16,855 students, including:
The city of Dayton has more than 35 private schools within the city, including:
Dayton has 33 charter schools. Three of the top five charter schools named in 2011 are K–8 schools managed by National Heritage Academies. Notable charter schools include:
The Dayton area was ranked tenth for higher education among metropolitan areas in the United States by Forbes in 2009. The city is home to two major universities. The University of Dayton is a private, Catholic institution founded in 1850 by the Marianist order. It has the only American Bar Association (ABA)-approved law school in the Dayton area. The University of Dayton is Ohio's largest private university and is also home to the University of Dayton Research Institute, which ranks third in the nation for sponsored materials research, and the Center for Tissue Regeneration and Engineering at Dayton, which focuses on human tissue regeneration.
The public Wright State University became a state university in 1967. Wright State University established the National Center for Medical Readiness, a national training program for disaster preparedness and relief. Wright State's Boonshoft School of Medicine is the Dayton area's only medical school and is a leader in biomedical research.
Dayton is also home to Sinclair Community College, the largest community college at a single location in Ohio and one of the nation's largest community colleges. Sinclair is acclaimed as one of the country's best community colleges. Sinclair was founded as the YMCA college in 1887.
Other schools just outside Dayton that shape the educational landscape are Antioch College and Antioch University, both in Yellow Springs, Central State University in Wilberforce, Kettering College of Medical Arts and School of Advertising Art in Kettering, DeVry University in Beavercreek, Cedarville University, Clark State Community College and Wittenberg University in Springfield. The Air Force Institute of Technology, which was founded in 1919 and serves as a graduate school for the United States Air Force, is at the nearby Wright-Patterson Air Force Base.
Dayton is served in print by The Dayton Daily News, the city's sole remaining daily newspaper. The Dayton Daily News is owned by Cox Enterprises. The Dayton region's main business newspaper is the Dayton Business Journal. The Dayton City Paper, a community paper focused on music, art, and independent thought ceased operation in 2018. The Dayton Weekly News has been published since 1993, providing news and information to Dayton's African-American community.
There are numerous magazines produced in and for the Dayton region. The Dayton Magazine provides insight into arts, food, and events. Focus on Business is published by the Chamber of Commerce to provide awareness of companies and initiatives affecting the regional economy
Nielsen Media Research ranked the 11-county Dayton television market as the No. 62 market in the United States. The market is served by stations affiliated with major American networks including: WDTN, channel 2 – NBC, operated by Nexstar Media Group; WHIO-TV, channel 7 – CBS, operated by Cox Media Group; WPTD, channel 16 – PBS, operated by ThinkTV, which also operates WPTO, assigned to Oxford; WKEF, channel 22 – ABC/Fox, operated by Sinclair Broadcasting; WBDT, channel 26 – The CW, operated by Vaughan Media (a shell corporation of Nexstar), assigned to Springfield; WKOI-TV, channel 43 – Ion Television, assigned to Richmond, Indiana; and WRGT-TV, channel 45 – My Network TV, operated under a local marketing agreement by Sinclair Broadcasting. The nationally syndicated morning talk show The Daily Buzz originated from WBDT, the former ACME Communications property in Miamisburg, before moving to its current home in Florida.
Dayton is also served by 42 AM and FM radio stations directly, and numerous other stations are heard from elsewhere in southwest Ohio, which serve outlying suburbs and adjoining counties.
The Greater Dayton Regional Transit Authority (RTA) operates public bus routes in the Dayton metro area. In addition to routes covered by traditional diesel-powered buses, RTA has several electric trolley bus routes. The Dayton trolleybus system is the second longest-running of the five remaining trolleybus systems in the U.S., having entered service in 1933. It is the present manifestation of an electric transit service that has operated continuously in Dayton since 1888.
Dayton operates a Greyhound Station which provides inter-city bus transportation to and from Dayton. The hub is in the Greater Dayton Regional Transit Authority North-West hub in Trotwood.
Dayton International Airport lies in a northern exclave of the city and offers service to 21 markets through 10 airlines. In 2008, it served 2.9 million passengers. The Dayton International Airport is also a significant regional air freight hub hosting FedEx Express, UPS Airlines, United States Postal Service, and major commercial freight carriers.
The Dayton area also has several regional airports. The Dayton–Wright Brothers Airport is a general aviation airport owned by the City of Dayton 10 miles (16 km) south of the central business district of Dayton on Springboro Pike in Miami Township. It serves as the reliever airport for Dayton International Airport. The airport primarily serves corporate and personal aircraft users. The Dahio Trotwood Airport, also known as Dayton-New Lebanon Airport, is a privately owned, public-use airport 7 miles (11 km) west of the central business district of Dayton. The Moraine Airpark is a privately owned, public-use airport 4 miles (6.4 km) southwest of the city of Dayton.
The Dayton region is primarily served by three interstates:
Other major routes for the region include:
From 2010 through 2017, the Ohio Department of Transportation (ODOT) performed a $533 million construction project to modify, reconstruct and widen I-75 through downtown Dayton, from Edwin C Moses Blvd. to Stanley Avenue.
Dayton hosts several inter-modal freight railroad terminals. Two Class I railroads, CSX and Norfolk Southern Railway, operate switching yards in the city.
Formerly the Baltimore and Ohio Railroad, New York Central Railroad and the Pennsylvania Railroad, and afterward, Amtrak made long-distance passenger train stops at Dayton Union Station on S. Sixth Street. The last train leaving there was the National Limited in October 1979.
Dayton's sister cities are: | [
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"text": "Dayton (/ˈdeɪtən/ ) is a city in and the county seat of Montgomery County, Ohio, United States. A small part of the city extends into Greene County. As of the 2020 census, the city proper had a population of 137,644, making it the sixth-most populous city in Ohio. Dayton anchors the state's fourth-largest metropolitan area, the Dayton metropolitan area, which had 814,049 residents. Dayton is located within Ohio's Miami Valley region, 50 miles (80 km) north of Cincinnati and 60 miles (97 km) west of Columbus. It is a principal city of the Dayton–Springfield–Sidney combined statistical area, home to a population of 1,086,512.",
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{
"paragraph_id": 1,
"text": "Dayton was founded in 1796 along the Great Miami River and named after Jonathan Dayton, a Founding Father who owned a significant amount of land in the area. It grew in the 19th century as a canal town and was home to many patents and inventors, most notably the Wright brothers, who developed the first successful motor-operated airplane. It later developed an industrialized economy and was home to the Dayton Project, a branch of the larger Manhattan Project, to develop polonium triggers used in early atomic bombs. With the decline of heavy manufacturing in the late 20th century, Dayton's businesses have diversified into a service economy.",
"title": ""
},
{
"paragraph_id": 2,
"text": "Ohio's borders are within 500 miles (800 km) of roughly 60 percent of the country's population and manufacturing infrastructure, making Dayton a logistics hub. The city is home to Wright-Patterson Air Force Base, a significant contributor to research and development in the industrial, aeronautical, and astronautical engineering fields. Along with defense and aerospace, healthcare accounts for much of the Dayton area's economy. Significant institutions in Dayton include the Air Force Institute of Technology, Carillon Historical Park, Dayton Art Institute, Dayton Performing Arts Alliance, National Museum of the United States Air Force, and University of Dayton.",
"title": ""
},
{
"paragraph_id": 3,
"text": "Dayton was founded on April 1, 1796, by 12 settlers known as the Thompson Party. They traveled in March from Cincinnati up the Great Miami River by pirogue and landed at what is now St. Clair Street, where they found two small camps of Native Americans. Among the Thompson Party was Benjamin Van Cleve, whose memoirs provide insights into the Ohio Valley's history. Two other groups traveling overland arrived several days later. The oldest surviving building is Newcom Tavern, which was used for various purposes, including housing Dayton's first church, which is still in existence.",
"title": "History"
},
{
"paragraph_id": 4,
"text": "In 1797, Daniel C. Cooper laid out Mad River Road, the first overland connection between Cincinnati and Dayton, opening the \"Mad River Country\" to settlement. Ohio was admitted into the Union in 1803, and the village of Dayton was incorporated in 1805 and chartered as a city in 1841. The city was named after Jonathan Dayton, a captain in the American Revolutionary War who signed the U.S. Constitution and owned a significant amount of land in the area. In 1827, construction on the Dayton–Cincinnati canal began, which provided a better way to transport goods from Dayton to Cincinnati and contributed significantly to Dayton's economic growth during the 1800s.",
"title": "History"
},
{
"paragraph_id": 5,
"text": "Innovation led to business growth in the region. In 1884, John Henry Patterson acquired James Ritty's National Manufacturing Company along with his cash register patents and formed the National Cash Register Company (NCR). The company manufactured the first mechanical cash registers and played a crucial role in the shaping of Dayton's reputation as an epicenter for manufacturing in the early 1900s. In 1906, Charles F. Kettering, a leading engineer at the company, helped develop the first electric cash register, which propelled NCR into the national spotlight. NCR also helped develop the US Navy Bombe, a code-breaking machine that helped crack the Enigma machine cipher during World War II.",
"title": "History"
},
{
"paragraph_id": 6,
"text": "Dayton has been the home for many patents and inventions since the 1870s. According to the National Park Service, citing information from the U.S. Patent Office, Dayton had granted more patents per capita than any other U.S. city in 1890 and ranked fifth in the nation as early as 1870. The Wright brothers, inventors of the airplane, and Charles F. Kettering, world-renowned for his numerous inventions, hailed from Dayton. The city was also home to James Ritty's Incorruptible Cashier, the first mechanical cash register, and Arthur E. Morgan's hydraulic jump, a flood prevention mechanism that helped pioneer hydraulic engineering. Paul Laurence Dunbar, an African-American poet and novelist, penned his most famous works in the late 19th century and became an integral part of the city's history.",
"title": "History"
},
{
"paragraph_id": 7,
"text": "Powered aviation began in Dayton. Orville and Wilbur Wright were the first to construct and demonstrate powered flight. Although the first flight was in Kitty Hawk, North Carolina, their Wright Flyer was built in and returned to Dayton for improvements and further flights at Huffman Field, a cow pasture eight miles (13 km) northeast of Dayton, near the current Wright-Patterson Air Force Base.",
"title": "History"
},
{
"paragraph_id": 8,
"text": "When the government tried to move development to Langley field in southern Virginia, six Dayton businessmen including Edward A. Deeds, formed the Dayton-Wright Airplane Company in Moraine and established a flying field. Deeds also opened a field to the north in the flood plain of the Great Miami River between the confluences of that river, the Stillwater River, and the Mad River, near downtown Dayton. Later named McCook Field for Alexander McDowell McCook, an American Civil War general, this became the Army Signal Corps' primary aviation research and training location. Wilbur Wright also purchased land near Huffman prairie to continue their research.",
"title": "History"
},
{
"paragraph_id": 9,
"text": "During World War I, the Army purchased 40 acres adjacent to Huffman Prairie for the Fairfield Aviation General Supply Depot. As airplanes developed more capability, they needed more runway space than McCook could offer, and a new location was sought. The Patterson family formed the Dayton Air Service Committee, Inc which held a campaign that raised $425,000 in two days and purchased 4,520.47 acres (18.2937 km) northeast of Dayton, including Wilbur Wright Field and the Huffman Prairie Flying Field. Wright Field was \"formally dedicated\" on October 12, 1927. After World War II, Wright Field and the adjacent Patterson Field, Dayton Army Air Field, and Clinton Army Air Field were merged as the Headquarters, Air Force Technical Base. On January 13, 1948, the facility was renamed Wright-Patterson Air Force Base.",
"title": "History"
},
{
"paragraph_id": 10,
"text": "A catastrophic flood in March 1913, known as the Great Dayton Flood, led to the creation of the Miami Conservancy District, a series of dams as well as hydraulic pumps installed around Dayton, in 1914.",
"title": "History"
},
{
"paragraph_id": 11,
"text": "Like other cities across the country, Dayton was heavily involved in the war effort during World War II. Several locations around the city hosted the Dayton Project, a branch of the larger Manhattan Project, to develop polonium triggers used in early atomic bombs. The war efforts led to a manufacturing boom throughout the city, including high demand for housing and other services. At one point, emergency housing was put into place due to a housing shortage in the region, much of which is still in use today.",
"title": "History"
},
{
"paragraph_id": 12,
"text": "Alan Turing is widely considered to be the father of theoretical computer science and artificial intelligence. He visited the National Cash Register (NCR) company in Dayton in December 1942. He was able to show that it was not necessary to build 336 Bombes, so the initial order was scaled down to 96 machines to decipher German Enigma-machine-encrypted secret messages during World War II.",
"title": "History"
},
{
"paragraph_id": 13,
"text": "Between the 1940s and the 1970s, the city saw significant growth in suburban areas from population migration. Veterans were returning from military service in large numbers seeking industrial and manufacturing jobs, a part of the local industry that was expanding rapidly. Advancements in architecture also contributed to the suburban boom. New, modernized shopping centers and the Interstate Highway System allowed workers to commute greater distances and families to live further from the downtown area. More than 127,000 homes were built in Montgomery County during the 1950s.",
"title": "History"
},
{
"paragraph_id": 14,
"text": "During this time, the city was the site of several race riots, including one in 1955 following the murder of Emmett Till, the 1966 Dayton race riot, two in 1967 (following a speech by civil rights activist H. Rap Brown and another following the police killing of an African American man), and one in 1968 as part of the nationwide King assassination riots.",
"title": "History"
},
{
"paragraph_id": 15,
"text": "Since the 1980s, however, Dayton's population has declined, mainly due to the loss of manufacturing jobs and decentralization of metropolitan areas, as well as the national housing crisis that began in 2008. While much of the state has suffered for similar reasons, the impact on Dayton has been greater than most. Dayton had the third-greatest percentage loss of population in the state since the 1980s, behind Cleveland and Youngstown. Despite this, Dayton has begun diversifying its workforce from manufacturing into other growing sectors such as healthcare and education.",
"title": "History"
},
{
"paragraph_id": 16,
"text": "In 1995, the Dayton Agreement, a peace accord between the parties to the hostilities of the conflict in Bosnia-Herzegovina and the former Yugoslavia, was negotiated at Wright-Patterson Air Force Base, near Fairborn, Ohio, from November 1 to 21.",
"title": "History"
},
{
"paragraph_id": 17,
"text": "Richard Holbrooke wrote about these events in his memoirs:",
"title": "History"
},
{
"paragraph_id": 18,
"text": "There was also a real Dayton out there, a charming Ohio city, famous as the birthplace of the Wright brothers. Its citizens energized us from the outset. Unlike the population of, say, New York City, Geneva or Washington, which would scarcely notice another conference, Daytonians were proud to be part of history. Large signs at the commercial airport hailed Dayton as the \"temporary center of international peace.\" The local newspapers and television stations covered the story from every angle, drawing the people deeper into the proceedings. When we ventured into a restaurant or a shopping center downtown, people crowded around, saying that they were praying for us. Warren Christopher was given at least one standing ovation in a restaurant. Families on the airbase placed \"candles of peace\" in their front windows, and people gathered in peace vigils outside the base. One day they formed a \"peace chain,\" although it was not large enough to surround the sprawling eight-thousand-acre base. Ohio's famous ethnic diversity was on display.",
"title": "History"
},
{
"paragraph_id": 19,
"text": "Downtown expansion that began in the 2000s has helped revitalize the city and encourage growth. Day Air Ballpark, home of the Dayton Dragons, was built in 2000. The highly successful minor league baseball team has been an integral part of Dayton's culture. In 2001, the city's public park system, Five Rivers MetroParks, built RiverScape MetroPark, an outdoor entertainment venue that attracts more than 400,000 visitors each year. A new performance arts theater, the Schuster Center, opened in 2003. A large health network in the region, Premier Health Partners, expanded its Miami Valley Hospital with a 12-story tower addition.",
"title": "History"
},
{
"paragraph_id": 20,
"text": "In 2010, the Downtown Dayton Partnership, in cooperation with the City of Dayton and community leaders, introduced the Greater Downtown Dayton Plan. It focuses on job creation and retention, infrastructure improvements, housing, recreation, and collaboration. The plan is to be implemented through the year 2020.",
"title": "History"
},
{
"paragraph_id": 21,
"text": "Dayton is known as the \"Gem City\". The nickname's origin is uncertain, but several theories exist. In the early 19th century, a well-known racehorse named Gem hailed from Dayton. In 1845, an article published in the Cincinnati Daily Chronicle by an author known as T stated:",
"title": "History"
},
{
"paragraph_id": 22,
"text": "In a small bend of the Great Miami River, with canals on the east and south, it can be fairly said, without infringing on the rights of others, that Dayton is the gem of all our interior towns. It possesses wealth, refinement, enterprise, and a beautiful country, beautifully developed.",
"title": "History"
},
{
"paragraph_id": 23,
"text": "In the late 1840s, Major William D. Bickham of the Dayton Journal began a campaign to nickname Dayton the \"Gem City.\" The name was adopted by the city's Board of Trade several years later. Paul Laurence Dunbar referred to the nickname in his poem, \"Toast to Dayton\", as noted in the following excerpt:",
"title": "History"
},
{
"paragraph_id": 24,
"text": "She shall ever claim our duty, For she shines—the brightest gem That has ever decked with beauty Dear Ohio's diadem.",
"title": "History"
},
{
"paragraph_id": 25,
"text": "Dayton also plays a role in a nickname given to the state of Ohio, \"Birthplace of Aviation.\" Dayton is the hometown of the Wright brothers, aviation pioneers who are credited with inventing and building the first practical airplane in history. After their first manned flights in Kitty Hawk, North Carolina, which they had chosen due to its ideal weather and climate conditions, the Wrights returned to Dayton and continued testing at nearby Huffman Prairie.",
"title": "History"
},
{
"paragraph_id": 26,
"text": "Additionally, Dayton is colloquially referred to as \"Little Detroit\". This nickname comes from Dayton's prominence as a Midwestern manufacturing center.",
"title": "History"
},
{
"paragraph_id": 27,
"text": "According to the United States Census Bureau, the city has a total area of 56.50 square miles (146.33 km), of which 55.65 square miles (144.13 km) is land and 0.85 square miles (2.20 km) is water.",
"title": "Geography"
},
{
"paragraph_id": 28,
"text": "Dayton's climate features warm, muggy summers and cold, dry winters, and is classified as a humid continental climate (Köppen Dfa). Unless otherwise noted, all normal figures quoted within the text below are from the official climatology station, Dayton International Airport, at an elevation of 1,000 ft (304.8 m) about 10 mi (16 km) to the north of downtown Dayton, which lies within the valley of the Miami River; thus temperatures there are typically cooler than in downtown.",
"title": "Geography"
},
{
"paragraph_id": 29,
"text": "At the airport, monthly mean temperatures range from 27.5 °F (−2.5 °C) in January to 74.1 °F (23.4 °C) in July. The highest temperature ever recorded in Dayton was 108 °F (42 °C) on July 22, 1901, and the coldest was −28 °F (−33 °C) on February 13 during the Great Blizzard of 1899. On average, there are 14 days of 90 °F (32 °C)+ highs and 4.5 nights of sub-0 °F (−18 °C) lows annually. Snow is moderate, with a normal seasonal accumulation of 23.3 in (59 cm), usually occurring from November to March, occasionally April, and rarely October. Precipitation averages 41.1 inches (1,040 mm) annually, with total rainfall peaking in May.",
"title": "Geography"
},
{
"paragraph_id": 30,
"text": "Dayton is subject to severe weather typical of the Midwestern United States. Tornadoes are possible from the spring to the fall. Floods, blizzards, and severe thunderstorms can also occur.",
"title": "Geography"
},
{
"paragraph_id": 31,
"text": "On Memorial Day of 2019, Dayton suffered extensive property damage and one death during a tornado outbreak, in which a total of 15 tornadoes touched down in the Dayton area. Although some of the tornadoes were only EF0 and remained on the ground for less than a mile, one was an EF4 measuring a half-mile-wide (805 meters), which tore through the communities of Brookville, Trotwood, Dayton, and Riverside. Several streets were closed, including portions of I-75 and North Dixie Street. 64,000 residents lost power and much of the region's water supply was cut off.",
"title": "Geography"
},
{
"paragraph_id": 32,
"text": "The Dayton Audubon Society is the National Audubon Society's local chapter. The Dayton chapter manages local activities contributing to the annual, hemisphere-wide Christmas Bird Count. The Chapter began participation in the National Count in 1924. The local Count was initially coordinated by Ben Blincoe, who was succeeded by Jim Hill in 1970. In the mid-1960s, the freezing of Lake Erie and associated marshlands led species of waterfowl to appear in the Dayton-area, where surface waters remained unfrozen. Nine varieties of birds have been observed every year in the Dayton area: downy woodpecker, Carolina chickadee, tufted titmouse, brown creeper, cardinal, junco, tree sparrow, song sparrow and crow.",
"title": "Geography"
},
{
"paragraph_id": 33,
"text": "Unlike many Midwestern cities its age, Dayton has very broad and straight downtown streets (generally two or three full lanes in each direction) that improved access to the downtown even after the automobile became popular. The main reason for the broad streets was that Dayton was a marketing and shipping center from its beginning; streets were broad to enable wagons drawn by teams of three to four pairs of oxen to turn around. Also, some of today's streets were once barge canals flanked by draw-paths.",
"title": "Cityscape"
},
{
"paragraph_id": 34,
"text": "A courthouse building was built in downtown Dayton in 1888 to supplement Dayton's original Neoclassical courthouse, which still stands. This second, \"new\" courthouse has since been replaced with new facilities as well as a park. The Old Court House has been a favored political campaign stop. On September 17, 1859, Abraham Lincoln delivered an address on its steps. Eight other presidents have visited the courthouse, either as presidents or during presidential campaigns: Andrew Johnson, James Garfield, John F. Kennedy, Lyndon B. Johnson, Richard Nixon, Gerald Ford, Ronald Reagan, and Bill Clinton.",
"title": "Cityscape"
},
{
"paragraph_id": 35,
"text": "The Dayton Arcade, which opened on March 3, 1904, was built in the hopes of replacing open-air markets throughout the city. Throughout the decades, the Arcade has gone through many transformations but has retained its charm. Some of its main features include a Flemish facade at the Third Street entrance, a glass dome above the Arcade rotunda, and a chateau roof line above the Third Street facade. The Dayton Arcade is currently under renovations with no official completion date set.",
"title": "Cityscape"
},
{
"paragraph_id": 36,
"text": "In 2009, the CareSource Management Group finished construction of a $55 million corporate headquarters in downtown Dayton. The 300,000-square-foot (28,000 m), 10-story building was downtown's first new office tower in more than a decade.",
"title": "Cityscape"
},
{
"paragraph_id": 37,
"text": "Dayton's two tallest buildings are the Kettering Tower at 408 ft (124 m) and the KeyBank Tower at 385 ft (117 m). Kettering Tower was originally Winters Tower, the headquarters of Winters Bank. The building was renamed after Virginia Kettering when Winters was merged into Bank One. KeyBank Tower was known as the MeadWestvaco Tower before KeyBank gained naming rights to the building in 2008.",
"title": "Cityscape"
},
{
"paragraph_id": 38,
"text": "Ted Rall said in 2015 that over the last five decades Dayton has been demolishing some of its architecturally significant buildings to reduce the city's rental vacancy rate and thus increase the occupancy rate.",
"title": "Cityscape"
},
{
"paragraph_id": 39,
"text": "Dayton's ten historic neighborhoods—Oregon District, Wright Dunbar, Dayton View, Grafton Hill, McPherson Town, Webster Station, Huffman, Kenilworth, St. Anne's Hill, and South Park—feature mostly single-family houses and mansions in the Neoclassical, Jacobethan, Tudor Revival, English Gothic, Chateauesque, Craftsman, Queen Anne, Georgian Revival, Colonial Revival, Renaissance Revival Architecture, Shingle Style Architecture, Prairie, Mission Revival, Eastlake/Italianate, American Foursquare, and Federal styles. Downtown Dayton is also a large area that encompasses several neighborhoods itself and has seen a recent uplift and revival.",
"title": "Cityscape"
},
{
"paragraph_id": 40,
"text": "Dayton's suburbs with a population of 10,000 or more include Beavercreek, Centerville, Clayton, Englewood, Fairborn, Harrison Township, Huber Heights, Kettering, Miami Township, Miamisburg, Oakwood, Riverside, Springboro, Trotwood, Vandalia, Washington Township, West Carrollton, and Xenia.",
"title": "Cityscape"
},
{
"paragraph_id": 41,
"text": "In the federal government's National Urban Policy and New Community Development Act of 1970, funding was provided for thirteen \"new towns\" or planned cities throughout the country. One location was set to become a suburb of Dayton and was known variously as Brookwood or Newfields. The goal was to have an entirely new suburb that would eventually house about 35,000 residents. The new town was to be located between Trotwood and Brookville, and modeled on the ideas of Ian McHarg. The project was abandoned in 1978 and most of the land became Sycamore State Park.",
"title": "Cityscape"
},
{
"paragraph_id": 42,
"text": "Dayton's population declined significantly from a peak of 262,332 residents in 1960 to only 141,759 in 2010. This was in part due to the slowdown of the region's manufacturing and the growth of Dayton's affluent suburbs including Oakwood, Englewood, Beavercreek, Springboro, Miamisburg, Kettering, and Centerville. The city's most populous ethnic group, white, declined from 78.1% in 1960 to 51.7% by 2010. Recent census estimates show a population decline since 2010.",
"title": "Demographics"
},
{
"paragraph_id": 43,
"text": "As of the 2000 census, the median income for a household in the city was $27,523, and the median income for a family was $34,978. Males had a median income of $30,816 versus $24,937 for females. The per capita income for the city was $34,724. About 18.2% of families and 23.0% of the population were below the poverty line, including 32.0% of those under age 18 and 15.3% of those age 65 or over.",
"title": "Demographics"
},
{
"paragraph_id": 44,
"text": "As of the 2010 census, there were 141,759 people, 58,404 households, and 31,064 families residing in the city. The population density was 2,543.2 inhabitants per square mile (981.9/km). There were 74,065 housing units at an average density of 1,330.9 per square mile (513.9/km). The racial makeup of the city was 51.7% White, 42.9% African American, 0.3% Native American, 0.9% Asian, 1.3% from other races, and 2.9% from two or more races. Hispanic or Latino of any race were 3.0% of the population.",
"title": "Demographics"
},
{
"paragraph_id": 45,
"text": "There were 58,404 households, of which 28.3% had children under the age of 18 living with them, 25.9% were married couples living together, 21.4% had a female householder with no husband present, 5.9% had a male householder with no wife present, and 46.8% were non-families. 38.8% of all households were made up of individuals, and 11.2% had someone living alone who was 65 years of age or older. The average household size was 2.26, and the average family size was 3.03.",
"title": "Demographics"
},
{
"paragraph_id": 46,
"text": "The median age in the city was 34.4 years. 22.9% of residents were under the age of 18; 14.2% were between the ages of 18 and 24; 25.3% were from 25 to 44; 25.8% were from 45 to 64, and 11.8% were 65 years of age or older. The gender makeup of the city was 48.7% male and 51.3% female.",
"title": "Demographics"
},
{
"paragraph_id": 47,
"text": "Dayton's crime declined between 2003 and 2008 in key categories according to FBI Uniform Crime Reports and Dayton Police Department data. In 2009, crime continued to fall in the city of Dayton. Crime in the categories of forcible rape, aggravated assault, property crime, motor vehicle theft, robbery, burglary, theft and arson all showed declines for 2009. Overall, crime in Dayton dropped 40% over the previous year. The Dayton Police Department reported a total of 39 murders in 2016, which marked a 39.3% increase in homicides from 2015.",
"title": "Crime"
},
{
"paragraph_id": 48,
"text": "John Dillinger, a bank robber during the early 1930s, was captured and arrested by Dayton city police while visiting his girlfriend at a high-class boarding house in downtown Dayton.",
"title": "Crime"
},
{
"paragraph_id": 49,
"text": "On August 4, 2019, a mass shooting took place in Dayton. Ten people were killed, including the perpetrator; and twenty-seven were injured.",
"title": "Crime"
},
{
"paragraph_id": 50,
"text": "Dayton's economy is relatively diversified and vital to the overall economy of the state of Ohio. In 2008 and 2009, Site Selection magazine ranked Dayton the #1 medium-sized metropolitan area in the U.S. for economic development. Dayton is also among the top 100 metropolitan areas in both exports and export-related jobs, ranked 16 and 14 respectively by the Brookings Institution. The 2010 report placed the value of exports at $4.7 billion and the number of export-related jobs at 44,133. The Dayton Metropolitan Statistical Area ranks 4th in Ohio's Gross Domestic Product with a 2008 industry total of $33.78 billion. Additionally, Dayton ranks third among 11 major metropolitan areas in Ohio for exports to foreign countries. The Dayton Development Coalition is attempting to leverage the region's large water capacity, estimated to be 1.5 trillion gallons of renewable water aquifers, to attract new businesses. Moody's Investment Services revised Dayton's bond rating from A1 to the stronger rating of Aa2 as part of its global recalibration process. Standard & Poor's upgraded Dayton's rating from A+ to AA− in the summer of 2009.",
"title": "Economy"
},
{
"paragraph_id": 51,
"text": "Bloomberg Businessweek ranked Dayton in 2010 as one of the best places in the U.S. for college graduates looking for a job. Companies such as Reynolds and Reynolds, Stratacache, CareSource, DP&L (soon AES inc), LexisNexis, Kettering Health Network, Premier Health Partners, and Standard Register have their headquarters in Dayton. It is also the former home of the Speedwell Motor Car Company, MeadWestvaco (formerly known as the Mead Paper Company), and NCR. NCR was headquartered in Dayton for over 125 years and was a major innovator in computer technology.",
"title": "Economy"
},
{
"paragraph_id": 52,
"text": "The Dayton region gave birth to aviation and is known for its high concentration of aerospace and aviation technology. In 2009, Governor Ted Strickland designated Dayton as Ohio's aerospace innovation hub, the state's first such technology hub. Two major United States research and development organizations have leveraged Dayton's historical leadership in aviation and maintain their headquarters in the area: The National Air and Space Intelligence Center (NASIC) and the Air Force Research Laboratory (AFRL). Both have their headquarters at Wright-Patterson Air Force Base.",
"title": "Economy"
},
{
"paragraph_id": 53,
"text": "Several research organizations support NASIC, AFRL, and the Dayton community. The Advanced Technical Intelligence Center is a confederation of government, academic, and industry partners. The University of Dayton Research Institute (UDRI) is led by the University of Dayton. The Cognitive Technologies Division (CTD) of Applied Research Associates, Inc., which carries out human-centered research and design, is headquartered in the Dayton suburb of Fairborn. The city of Dayton has started Tech Town, a development project to attract technology-based firms and revitalize the downtown area. Tech Town is home to the world's first RFID business incubator. The University of Dayton–led Institute for Development & Commercialization of Sensor Technologies (IDCAST) at TechTown is a center for remote sensing and sensing technology. It is one of Dayton's technology business incubators housed in The Entrepreneurs Center building.",
"title": "Economy"
},
{
"paragraph_id": 54,
"text": "The Kettering Health Network and Premier Health Partners have a major role on the Dayton area's economy. Hospitals in the Greater Dayton area have an estimated combined employment of nearly 32,000 and a yearly economic impact of $6.8 billion. In addition, several Dayton area hospitals consistently earn top national ranking and recognition including the U.S. News & World Report's list of \"America's Best Hospitals\" as well as many of HealthGrades top ratings. The most notable hospitals are Miami Valley Hospital and Kettering Medical Center.",
"title": "Economy"
},
{
"paragraph_id": 55,
"text": "The Dayton region has several key institutes and centers for health care. The Center for Tissue Regeneration and Engineering at Dayton focuses on the science and development of human tissue regeneration. The National Center for Medical Readiness (NCMR) is also in the Dayton area. The center includes Calamityville, which is a disaster training facility. Over five years, Calamityville is estimated to have a regional economic impact of $374 million. Also, the Neurological Institute at Miami Valley Hospital is an institute focused on the diagnosis, treatment, and research of neurological disorders.",
"title": "Economy"
},
{
"paragraph_id": 56,
"text": "According to the city's 2019 Comprehensive Annual Financial Report, the top employers in the city proper are:",
"title": "Economy"
},
{
"paragraph_id": 57,
"text": "The Dayton Region ranked within the top 10% in the nation in arts and culture. In a 2012 readers' poll by American Style magazine, Dayton ranked #2 in the country among mid-size cities as an arts destination, ranking higher than larger cities such as Atlanta, St. Louis, and Cincinnati. Dayton is the home of the Dayton Art Institute.",
"title": "Arts and culture"
},
{
"paragraph_id": 58,
"text": "The Benjamin and Marian Schuster Performing Arts Center in downtown Dayton is a world-class performing arts center and the home venue of the Dayton Philharmonic Orchestra, Dayton Opera, and the Dayton Ballet. In addition to philharmonic and opera performances, the Schuster Center hosts concerts, lectures, and traveling Broadway shows, and is a popular spot for weddings and other events. The historic Victoria Theatre in downtown Dayton hosts concerts, traveling Broadway shows, ballet, a summertime classic film series, and more. The Loft Theatre, also downtown, is the home of the Human Race Theatre Company. The Dayton Playhouse, in West Dayton, is the site of numerous plays and theatrical productions. Between 1957 and 1995, the Kenley Players presented live theater productions in Dayton. In 2013, John Kenley was inducted into the Dayton Theatre Hall of Fame. Dayton is also home to the Winter Guard International world finals, hosting finals for winter guard, indoor percussion, and indoor winds.",
"title": "Arts and culture"
},
{
"paragraph_id": 59,
"text": "Dayton is the home to several ballet companies including:",
"title": "Arts and culture"
},
{
"paragraph_id": 60,
"text": "Front Street, the largest artists' collective in Dayton, is housed in three industrial buildings on East Second Street.",
"title": "Arts and culture"
},
{
"paragraph_id": 61,
"text": "The Vectren Dayton Air Show is an annual air show that takes place at the Dayton International Airport. The Vectren Dayton Airshow is one of the largest air shows in the United States.",
"title": "Arts and culture"
},
{
"paragraph_id": 62,
"text": "The Dayton area is served by Five Rivers MetroParks, encompassing 14,161 acres (5,731 ha) over 23 facilities for year-round recreation, education, and conservation. In cooperation with the Miami Conservancy District, the MetroParks maintains over 70 miles (113 km) of paved, multi-use scenic trails that connect Montgomery County with Greene, Miami, Warren, and Butler counties.",
"title": "Arts and culture"
},
{
"paragraph_id": 63,
"text": "Dayton was home to a thriving funk music scene from the 1970s to the early 1980s, that included bands such as Ohio Players, Roger Troutman & Zapp, Lakeside, Sun, Dayton, Heatwave, and Slave.",
"title": "Arts and culture"
},
{
"paragraph_id": 64,
"text": "Dayton was also the birthplace to several influential indie and punk bands such as The Breeders, Guided by Voices, and Brainiac.",
"title": "Arts and culture"
},
{
"paragraph_id": 65,
"text": "From 1996 to 1998, Dayton hosted the National Folk Festival. Since then, the annual Cityfolk Festival has continued to bring folk, ethnic, and world music and arts to Dayton. The Five Rivers MetroParks also owns and operates the PNC Second Street Market near downtown Dayton.",
"title": "Arts and culture"
},
{
"paragraph_id": 66,
"text": "The Dayton area hosts several arenas and venues. South of Dayton in Kettering is the Fraze Pavilion, whose notable performances have included the Backstreet Boys, Boston, and Steve Miller Band. South of downtown, on the banks of the Great Miami River, is the University of Dayton Arena, home venue for the University of Dayton Flyers basketball teams and the location of various other events and concerts. It also hosts the Winter Guard International championships, at which hundreds of percussion and color guard ensembles from around the world compete. In addition, the Dayton Amateur Radio Association hosts the annual Dayton Hamvention, North America's largest hamfest, at the Greene County Fairgrounds in nearby Xenia. The Nutter Center, which is just east of Dayton in the suburb of Fairborn, is the home arena for athletics of Wright State University and the former Dayton Bombers hockey team. This venue is used for many concerts, community events, and various national traveling shows and performances.",
"title": "Arts and culture"
},
{
"paragraph_id": 67,
"text": "The Oregon District is a historic residential and commercial district in southeast downtown Dayton. The district is populated with art galleries, specialty shops, pubs, nightclubs, and coffee houses.",
"title": "Arts and culture"
},
{
"paragraph_id": 68,
"text": "The city of Dayton is also host to yearly festivals, such as the Dayton Celtic Festival, the Dayton Blues Festival, Dayton Music Fest, Urban Nights, Women in Jazz, the African American and Cultural Festival, and the Dayton Reggae Fest.",
"title": "Arts and culture"
},
{
"paragraph_id": 69,
"text": "The city's fine dining restaurants include The Pine Club, a nationally known steakhouse.",
"title": "Arts and culture"
},
{
"paragraph_id": 70,
"text": "Dayton is home to a variety of pizza chains that have become woven into local culture, the most notable of which are Cassano's and Marion's Piazza, both of which produce Dayton-style pizza, which has a thin, crisp, salty crust dusted on the bottom with cornmeal and topped with a thin layer of thick unsweetened sauce. Cheese and other topping ingredients are heavily distributed and spread edge-to-edge with no outer rim of crust, and the finished pizza is cut into bite-size squares.",
"title": "Arts and culture"
},
{
"paragraph_id": 71,
"text": "Notable Dayton-based restaurant chains include Hot Head Burritos.",
"title": "Arts and culture"
},
{
"paragraph_id": 72,
"text": "In addition to restaurants, the city is also home to Esther Price Candies, a candy and chocolate company, and Mike-sells, the oldest potato chip company in the United States.",
"title": "Arts and culture"
},
{
"paragraph_id": 73,
"text": "The city began developing a reputation for its number of breweries and craft beer venues by the late 2010s.",
"title": "Arts and culture"
},
{
"paragraph_id": 74,
"text": "Many major religions are represented in Dayton. Christianity is represented in Dayton by dozens of denominations and their respective churches. Notable Dayton churches include the First Lutheran Church, Sacred Heart Church, and Ginghamsburg Church. Dayton's Muslim community is largely represented by the Islamic Society of Greater Dayton (ISGD), a Muslim community that includes a mosque on Josie Street. Dayton is also home to the United Theological Seminary, one of 13 seminaries affiliated with the United Methodist Church. Judaism is represented by Temple Israel. Hinduism is represented by the Hindu Temple of Dayton. Old North Dayton also has a number of Catholic churches built by immigrants from Lithuania, Poland, Hungary, and Germany.",
"title": "Arts and culture"
},
{
"paragraph_id": 75,
"text": "Tourism also accounts for one out of every 14 private sector jobs in the county. Tourism in the Dayton region is led by the National Museum of the United States Air Force at Wright-Patterson Air Force Base, the largest and oldest military aviation museum in the world. The museum draws over 1.3 million visitors per year and is one of the most-visited tourist attractions in Ohio. The museum houses the National Aviation Hall of Fame.",
"title": "Arts and culture"
},
{
"paragraph_id": 76,
"text": "Other museums also play significant roles in the tourism and economy of the Dayton area. The Dayton Art Institute, a museum of fine arts, owns collections containing more than 20,000 objects spanning 5,000 years of art and archaeological history. The Dayton Art Institute was rated one of the top 10 best art museums in the United States for children. The Boonshoft Museum of Discovery is a children's museum of science with numerous exhibits, one of which includes an indoor zoo with nearly 100 different animals.",
"title": "Arts and culture"
},
{
"paragraph_id": 77,
"text": "There are also some notable historical museums in the region. The Dayton Aviation Heritage National Historical Park, operated by the National Park Service, commemorates the lives and achievements of Dayton natives Orville and Wilbur Wright and Paul Laurence Dunbar. The Wright brothers' famous Wright Flyer III aircraft is housed in a museum at Carillon Historical Park. Dayton is also home to America's Packard Museum, which contains many restored historical Packard vehicles. SunWatch Indian Village/Archaeological Park, a partially reconstructed 12th-century prehistoric American Indian village, is on the south end of Dayton; it is organized around a central plaza dominated by wood posts forming an astronomical calendar. The park includes a museum where visitors can learn about the Indian history of the Miami Valley.",
"title": "Arts and culture"
},
{
"paragraph_id": 78,
"text": "Dayton was named National Geographic's outdoor adventure capital of the Midwest in 2019 due in large part to the metropolitan area's revitalized Five Rivers MetroPark, extensive bicycle and jogging trail system, urban green spaces, lakes and camping areas.",
"title": "Parks and recreation"
},
{
"paragraph_id": 79,
"text": "In cooperation with the Miami Conservancy District, Five Rivers MetroParks hosts 340 miles of paved trails, the largest network of paved off-street trails in the United States. The regional trail system represents over 35% of the 900 miles in Ohio's off-street trail network. In 2010, the city of Troy was named \"bike friendly\" by the League of American Bicyclists, which gave the city the organization's bronze designation. The honorable mention made Dayton one of two cities in Ohio to receive the award, the other being Columbus, and one of 15 cities nationwide.",
"title": "Parks and recreation"
},
{
"paragraph_id": 80,
"text": "The Dayton area is home to several minor league and semi pro teams, as well as NCAA Division I sports programs.",
"title": "Parks and recreation"
},
{
"paragraph_id": 81,
"text": "The Dayton Dragons professional baseball team is a Class A minor league affiliate for the Cincinnati Reds. The Dayton Dragons are the first (and only) team in minor league baseball history to sell out an entire season before it began and was voted as one of the top 10 hottest tickets to get in all of professional sports by Sports Illustrated. The Dayton Dragons 815 consecutive sellouts surpassed the NBA's Portland Trail Blazers for the longest sellout streak across all professional sports in the U.S.",
"title": "Parks and recreation"
},
{
"paragraph_id": 82,
"text": "The University of Dayton and Wright State University both host NCAA basketball. The University of Dayton Arena has hosted more games in the NCAA men's basketball tournament over its history than any other venue. UD Arena is also the site of the First Round games of the NCAA Tournament. In 2012, eight teams competed for the final four spots in the NCAA basketball tournament. Wright State University's NCAA men's basketball is the Wright State Raiders and the University of Dayton's NCAA men's basketball team is the Dayton Flyers.",
"title": "Parks and recreation"
},
{
"paragraph_id": 83,
"text": "The Dayton Gems were a minor league ice hockey team in the International Hockey League from 1964 to 1977, 1979 to 1980, and most recently 2009 to 2012. The Dayton Bombers were an ECHL ice hockey team from 1991 to 2009. They most recently played the North Division of the ECHL's American Conference. In June 2009, it was announced the Bombers would turn in their membership back to the league.",
"title": "Parks and recreation"
},
{
"paragraph_id": 84,
"text": "Despite the folding of the Bombers, hockey remained in Dayton as the Dayton Gems of the International Hockey League were formed in the fall of 2009 at Hara Arena. The Gems folded after the 2011–12 season. Shortly after the Gems folded, it was announced a new team, the Dayton Demonz, would begin play in 2012 in the Federal Hockey League (FHL). The Demonz folded in 2015 and were immediately replaced by the Dayton Demolition, also in the FHL. However, the Demolition would cease operations after only one season when Hara Arena decided to close due to financial difficulties.",
"title": "Parks and recreation"
},
{
"paragraph_id": 85,
"text": "Dayton hosted the first American Professional Football Association game (precursor to the NFL). The game was played at Triangle Park between the Dayton Triangles and the Columbus Panhandles on October 3, 1920, and is considered one of the first professional football games ever played. Football teams in the Dayton area include the Dayton Flyers and the Dayton Sharks.",
"title": "Parks and recreation"
},
{
"paragraph_id": 86,
"text": "The Dayton region is also known for the many golf courses and clubs that it hosts. The Miami Valley Golf Club, Moraine Country Club, NCR Country Club, and the Pipestone Golf Course are some of the more notable courses. Also, several PGA Championships have been held at area golf courses. The Miami Valley Golf Club hosted the 1957 PGA Championship, the Moraine Country Club hosted the 1945 PGA Championship, and the NCR Country club hosted the 1969 PGA Championship. Additionally, NCR CC hosted the 1986 U.S. Women's Open, the 2005 U.S. Senior Open, the 2013 State Team Championships and most recently the 2022 Senior Women's Open. Other notable courses include the Yankee Trace Golf Club, the Beavercreek Golf Club, Dayton Meadowbrook Country Club, Sycamore Creek Country Club, Heatherwoode Golf Club, Community Golf Course, and Kitty Hawk Golf Course.",
"title": "Parks and recreation"
},
{
"paragraph_id": 87,
"text": "The city of Dayton is the home to the Dayton Area Rugby Club which hosts their home games at the Dayton Rugby Grounds. As of 2018, the club fields two men's and one women's side for Rugby Union and several Rugby Sevens sides. The club also hosts the annual Gem City 7's tournament.",
"title": "Parks and recreation"
},
{
"paragraph_id": 88,
"text": "The Dayton City Commission is composed of the mayor and four city commissioners. Each city commission member is elected at-large on a non-partisan basis for four-year, overlapping terms. All policy items are decided by the city commission, which is empowered by the City Charter to pass ordinances and resolutions, adopt regulations, and appoint the city manager. The city manager is responsible for budgeting and implementing policies and initiatives. Dayton was the first large American city to adopt the city manager (Henry Matson Waite (engineer)), form of municipal government, in 1913.",
"title": "Government"
},
{
"paragraph_id": 89,
"text": "Dayton Public Schools operates 34 schools that serve 16,855 students, including:",
"title": "Education"
},
{
"paragraph_id": 90,
"text": "The city of Dayton has more than 35 private schools within the city, including:",
"title": "Education"
},
{
"paragraph_id": 91,
"text": "Dayton has 33 charter schools. Three of the top five charter schools named in 2011 are K–8 schools managed by National Heritage Academies. Notable charter schools include:",
"title": "Education"
},
{
"paragraph_id": 92,
"text": "The Dayton area was ranked tenth for higher education among metropolitan areas in the United States by Forbes in 2009. The city is home to two major universities. The University of Dayton is a private, Catholic institution founded in 1850 by the Marianist order. It has the only American Bar Association (ABA)-approved law school in the Dayton area. The University of Dayton is Ohio's largest private university and is also home to the University of Dayton Research Institute, which ranks third in the nation for sponsored materials research, and the Center for Tissue Regeneration and Engineering at Dayton, which focuses on human tissue regeneration.",
"title": "Education"
},
{
"paragraph_id": 93,
"text": "The public Wright State University became a state university in 1967. Wright State University established the National Center for Medical Readiness, a national training program for disaster preparedness and relief. Wright State's Boonshoft School of Medicine is the Dayton area's only medical school and is a leader in biomedical research.",
"title": "Education"
},
{
"paragraph_id": 94,
"text": "Dayton is also home to Sinclair Community College, the largest community college at a single location in Ohio and one of the nation's largest community colleges. Sinclair is acclaimed as one of the country's best community colleges. Sinclair was founded as the YMCA college in 1887.",
"title": "Education"
},
{
"paragraph_id": 95,
"text": "Other schools just outside Dayton that shape the educational landscape are Antioch College and Antioch University, both in Yellow Springs, Central State University in Wilberforce, Kettering College of Medical Arts and School of Advertising Art in Kettering, DeVry University in Beavercreek, Cedarville University, Clark State Community College and Wittenberg University in Springfield. The Air Force Institute of Technology, which was founded in 1919 and serves as a graduate school for the United States Air Force, is at the nearby Wright-Patterson Air Force Base.",
"title": "Education"
},
{
"paragraph_id": 96,
"text": "Dayton is served in print by The Dayton Daily News, the city's sole remaining daily newspaper. The Dayton Daily News is owned by Cox Enterprises. The Dayton region's main business newspaper is the Dayton Business Journal. The Dayton City Paper, a community paper focused on music, art, and independent thought ceased operation in 2018. The Dayton Weekly News has been published since 1993, providing news and information to Dayton's African-American community.",
"title": "Media"
},
{
"paragraph_id": 97,
"text": "There are numerous magazines produced in and for the Dayton region. The Dayton Magazine provides insight into arts, food, and events. Focus on Business is published by the Chamber of Commerce to provide awareness of companies and initiatives affecting the regional economy",
"title": "Media"
},
{
"paragraph_id": 98,
"text": "Nielsen Media Research ranked the 11-county Dayton television market as the No. 62 market in the United States. The market is served by stations affiliated with major American networks including: WDTN, channel 2 – NBC, operated by Nexstar Media Group; WHIO-TV, channel 7 – CBS, operated by Cox Media Group; WPTD, channel 16 – PBS, operated by ThinkTV, which also operates WPTO, assigned to Oxford; WKEF, channel 22 – ABC/Fox, operated by Sinclair Broadcasting; WBDT, channel 26 – The CW, operated by Vaughan Media (a shell corporation of Nexstar), assigned to Springfield; WKOI-TV, channel 43 – Ion Television, assigned to Richmond, Indiana; and WRGT-TV, channel 45 – My Network TV, operated under a local marketing agreement by Sinclair Broadcasting. The nationally syndicated morning talk show The Daily Buzz originated from WBDT, the former ACME Communications property in Miamisburg, before moving to its current home in Florida.",
"title": "Media"
},
{
"paragraph_id": 99,
"text": "Dayton is also served by 42 AM and FM radio stations directly, and numerous other stations are heard from elsewhere in southwest Ohio, which serve outlying suburbs and adjoining counties.",
"title": "Media"
},
{
"paragraph_id": 100,
"text": "The Greater Dayton Regional Transit Authority (RTA) operates public bus routes in the Dayton metro area. In addition to routes covered by traditional diesel-powered buses, RTA has several electric trolley bus routes. The Dayton trolleybus system is the second longest-running of the five remaining trolleybus systems in the U.S., having entered service in 1933. It is the present manifestation of an electric transit service that has operated continuously in Dayton since 1888.",
"title": "Transportation"
},
{
"paragraph_id": 101,
"text": "Dayton operates a Greyhound Station which provides inter-city bus transportation to and from Dayton. The hub is in the Greater Dayton Regional Transit Authority North-West hub in Trotwood.",
"title": "Transportation"
},
{
"paragraph_id": 102,
"text": "Dayton International Airport lies in a northern exclave of the city and offers service to 21 markets through 10 airlines. In 2008, it served 2.9 million passengers. The Dayton International Airport is also a significant regional air freight hub hosting FedEx Express, UPS Airlines, United States Postal Service, and major commercial freight carriers.",
"title": "Transportation"
},
{
"paragraph_id": 103,
"text": "The Dayton area also has several regional airports. The Dayton–Wright Brothers Airport is a general aviation airport owned by the City of Dayton 10 miles (16 km) south of the central business district of Dayton on Springboro Pike in Miami Township. It serves as the reliever airport for Dayton International Airport. The airport primarily serves corporate and personal aircraft users. The Dahio Trotwood Airport, also known as Dayton-New Lebanon Airport, is a privately owned, public-use airport 7 miles (11 km) west of the central business district of Dayton. The Moraine Airpark is a privately owned, public-use airport 4 miles (6.4 km) southwest of the city of Dayton.",
"title": "Transportation"
},
{
"paragraph_id": 104,
"text": "The Dayton region is primarily served by three interstates:",
"title": "Transportation"
},
{
"paragraph_id": 105,
"text": "Other major routes for the region include:",
"title": "Transportation"
},
{
"paragraph_id": 106,
"text": "From 2010 through 2017, the Ohio Department of Transportation (ODOT) performed a $533 million construction project to modify, reconstruct and widen I-75 through downtown Dayton, from Edwin C Moses Blvd. to Stanley Avenue.",
"title": "Transportation"
},
{
"paragraph_id": 107,
"text": "Dayton hosts several inter-modal freight railroad terminals. Two Class I railroads, CSX and Norfolk Southern Railway, operate switching yards in the city.",
"title": "Transportation"
},
{
"paragraph_id": 108,
"text": "Formerly the Baltimore and Ohio Railroad, New York Central Railroad and the Pennsylvania Railroad, and afterward, Amtrak made long-distance passenger train stops at Dayton Union Station on S. Sixth Street. The last train leaving there was the National Limited in October 1979.",
"title": "Transportation"
},
{
"paragraph_id": 109,
"text": "Dayton's sister cities are:",
"title": "Sister cities"
},
{
"paragraph_id": 110,
"text": "",
"title": "External links"
}
] | Dayton is a city in and the county seat of Montgomery County, Ohio, United States. A small part of the city extends into Greene County. As of the 2020 census, the city proper had a population of 137,644, making it the sixth-most populous city in Ohio. Dayton anchors the state's fourth-largest metropolitan area, the Dayton metropolitan area, which had 814,049 residents. Dayton is located within Ohio's Miami Valley region, 50 miles (80 km) north of Cincinnati and 60 miles (97 km) west of Columbus. It is a principal city of the Dayton–Springfield–Sidney combined statistical area, home to a population of 1,086,512. Dayton was founded in 1796 along the Great Miami River and named after Jonathan Dayton, a Founding Father who owned a significant amount of land in the area. It grew in the 19th century as a canal town and was home to many patents and inventors, most notably the Wright brothers, who developed the first successful motor-operated airplane. It later developed an industrialized economy and was home to the Dayton Project, a branch of the larger Manhattan Project, to develop polonium triggers used in early atomic bombs. With the decline of heavy manufacturing in the late 20th century, Dayton's businesses have diversified into a service economy. Ohio's borders are within 500 miles (800 km) of roughly 60 percent of the country's population and manufacturing infrastructure, making Dayton a logistics hub. The city is home to Wright-Patterson Air Force Base, a significant contributor to research and development in the industrial, aeronautical, and astronautical engineering fields. Along with defense and aerospace, healthcare accounts for much of the Dayton area's economy. Significant institutions in Dayton include the Air Force Institute of Technology, Carillon Historical Park, Dayton Art Institute, Dayton Performing Arts Alliance, National Museum of the United States Air Force, and University of Dayton. | 2001-07-28T00:59:06Z | 2023-12-28T09:19:58Z | [
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] | https://en.wikipedia.org/wiki/Dayton,_Ohio |
8,254 | Diode | A diode is a two-terminal electronic component that conducts current primarily in one direction (asymmetric conductance). It has low (ideally zero) resistance in one direction and high (ideally infinite) resistance in the other.
A semiconductor diode, the most commonly used type today, is a crystalline piece of semiconductor material with a p–n junction connected to two electrical terminals. It has an exponential current–voltage characteristic. Semiconductor diodes were the first semiconductor electronic devices. The discovery of asymmetric electrical conduction across the contact between a crystalline mineral and a metal was made by German physicist Ferdinand Braun in 1874. Today, most diodes are made of silicon, but other semiconducting materials such as gallium arsenide and germanium are also used.
The obsolete thermionic diode is a vacuum tube with two electrodes, a heated cathode and a plate, in which electrons can flow in only one direction, from cathode to plate.
Among many uses, diodes are found in rectifiers to convert alternating current (AC) power to direct current (DC), demodulation in radio receivers, and can even be used for logic or as temperature sensors. A common variant of a diode is a light-emitting diode, which is used as electric lighting and status indicators on electronic devices.
The most common function of a diode is to allow an electric current to pass in one direction (called the diode's forward direction), while blocking it in the opposite direction (the reverse direction). Therefore, the diode can be viewed as an electronic version of a check valve. This unidirectional behavior is called rectification and is used to convert alternating current (AC) to direct current (DC). As rectifiers, diodes can be used for such tasks as extracting modulation from radio signals in radio receivers.
However, diodes can have more complicated behavior than this simple on–off action, because of their nonlinear current–voltage characteristics. For instance, a diode's forward-direction voltage drop varies only a little with the current, and is more so a function of temperature; this effect can be used as a temperature sensor or as a voltage reference. And its high resistance to current flowing in the reverse direction suddenly drops to a low resistance when the reverse voltage across the diode reaches a value called the breakdown voltage. Semiconductor diodes in the forward direction also need to surpass a threshold voltage before being able to conduct electricity.
A semiconductor diode's current–voltage characteristic can be tailored by selecting the semiconductor materials and the doping impurities introduced into the materials during manufacture. These techniques are used to create special-purpose diodes that perform many different functions. For example, diodes are used to regulate voltage (Zener diodes), to protect circuits from high voltage surges (avalanche diodes), to electronically tune radio and TV receivers (varactor diodes), to generate radio-frequency oscillations (tunnel diodes, Gunn diodes, IMPATT diodes), and to produce light (light-emitting diodes). Tunnel, Gunn and IMPATT diodes exhibit negative resistance, which is useful in microwave and switching circuits.
Diodes, both vacuum and semiconductor, can be used as shot-noise generators.
Thermionic (vacuum-tube) diodes and solid-state (semiconductor) diodes were developed separately, at approximately the same time, in the early 1900s, as radio receiver detectors. Until the 1950s, vacuum diodes were used more frequently in radios because the early point-contact semiconductor diodes were less stable. In addition, most receiving sets had vacuum tubes for amplification that could easily have the thermionic diodes included in the tube (for example the 12SQ7 double diode triode), and vacuum-tube rectifiers and gas-filled rectifiers were capable of handling some high-voltage/high-current rectification tasks better than the semiconductor diodes (such as selenium rectifiers) that were available at that time.
In 1873, Frederick Guthrie observed that a grounded, white-hot metal ball brought in close proximity to an electroscope would discharge a positively charged electroscope, but not a negatively charged electroscope. In 1880, Thomas Edison observed unidirectional current between heated and unheated elements in a bulb, later called Edison effect, and was granted a patent on application of the phenomenon for use in a DC voltmeter. About 20 years later, John Ambrose Fleming (scientific adviser to the Marconi Company and former Edison employee) realized that the Edison effect could be used as a radio detector. Fleming patented the first true thermionic diode, the Fleming valve, in Britain on 16 November 1904 (followed by U.S. Patent 803,684 in November 1905). Throughout the vacuum tube era, valve diodes were used in almost all electronics such as radios, televisions, sound systems, and instrumentation. They slowly lost market share beginning in the late 1940s due to selenium rectifier technology and then to semiconductor diodes during the 1960s. Today they are still used in a few high power applications where their ability to withstand transient voltages and their robustness gives them an advantage over semiconductor devices, and in musical instrument and audiophile applications.
In 1874, German scientist Karl Ferdinand Braun discovered the "unilateral conduction" across a contact between a metal and a mineral. Indian scientist Jagadish Chandra Bose was the first to use a crystal for detecting radio waves in 1894. The crystal detector was developed into a practical device for wireless telegraphy by Greenleaf Whittier Pickard, who invented a silicon crystal detector in 1903 and received a patent for it on 20 November 1906. Other experimenters tried a variety of other minerals as detectors. Semiconductor principles were unknown to the developers of these early rectifiers. During the 1930s understanding of physics advanced and in the mid 1930s researchers at Bell Telephone Laboratories recognized the potential of the crystal detector for application in microwave technology. Researchers at Bell Labs, Western Electric, MIT, Purdue and in the UK intensively developed point-contact diodes (crystal rectifiers or crystal diodes) during World War II for application in radar. After World War II, AT&T used these in its microwave towers that criss-crossed the United States, and many radar sets use them even in the 21st century. In 1946, Sylvania began offering the 1N34 crystal diode. During the early 1950s, junction diodes were developed.
In 2022, the first superconducting diode effect without an external magnetic field was realized.
At the time of their invention, asymmetrical conduction devices were known as rectifiers. In 1919, the year tetrodes were invented, William Henry Eccles coined the term diode from the Greek roots di (from δί), meaning 'two', and ode (from οδός), meaning 'path'. The word diode however was already in use, as were triode, tetrode, pentode, hexode, as terms of multiplex telegraphy.
Although all diodes rectify, "rectifier" usually applies to diodes used for power supply, to differentiate them from diodes intended for small signal circuits.
A thermionic diode is a thermionic-valve device consisting of a sealed, evacuated glass or metal envelope containing two electrodes: a cathode and a plate. The cathode is either indirectly heated or directly heated. If indirect heating is employed, a heater is included in the envelope.
In operation, the cathode is heated to red heat, around 800–1,000 °C (1,470–1,830 °F). A directly heated cathode is made of tungsten wire and is heated by a current passed through it from an external voltage source. An indirectly heated cathode is heated by infrared radiation from a nearby heater that is formed of Nichrome wire and supplied with current provided by an external voltage source.
The operating temperature of the cathode causes it to release electrons into the vacuum, a process called thermionic emission. The cathode is coated with oxides of alkaline earth metals, such as barium and strontium oxides. These have a low work function, meaning that they more readily emit electrons than would the uncoated cathode.
The plate, not being heated, does not emit electrons; but is able to absorb them.
The alternating voltage to be rectified is applied between the cathode and the plate. When the plate voltage is positive with respect to the cathode, the plate electrostatically attracts the electrons from the cathode, so a current of electrons flows through the tube from cathode to plate. When the plate voltage is negative with respect to the cathode, no electrons are emitted by the plate, so no current can pass from the plate to the cathode.
Point-contact diodes were developed starting in the 1930s, out of the early crystal detector technology, and are now generally used in the 3 to 30 gigahertz range. Point-contact diodes use a small diameter metal wire in contact with a semiconductor crystal, and are of either non-welded contact type or welded contact type. Non-welded contact construction utilizes the Schottky barrier principle. The metal side is the pointed end of a small diameter wire that is in contact with the semiconductor crystal. In the welded contact type, a small P region is formed in the otherwise N-type crystal around the metal point during manufacture by momentarily passing a relatively large current through the device. Point contact diodes generally exhibit lower capacitance, higher forward resistance and greater reverse leakage than junction diodes.
A p–n junction diode is made of a crystal of semiconductor, usually silicon, but germanium and gallium arsenide are also used. Impurities are added to it to create a region on one side that contains negative charge carriers (electrons), called an n-type semiconductor, and a region on the other side that contains positive charge carriers (holes), called a p-type semiconductor. When the n-type and p-type materials are attached together, a momentary flow of electrons occurs from the n to the p side resulting in a third region between the two where no charge carriers are present. This region is called the depletion region because there are no charge carriers (neither electrons nor holes) in it. The diode's terminals are attached to the n-type and p-type regions. The boundary between these two regions called a p–n junction, is where the action of the diode takes place. When a sufficiently higher electrical potential is applied to the P side (the anode) than to the N side (the cathode), it allows electrons to flow through the depletion region from the N-type side to the P-type side. The junction does not allow the flow of electrons in the opposite direction when the potential is applied in reverse, creating, in a sense, an electrical check valve.
Another type of junction diode, the Schottky diode, is formed from a metal–semiconductor junction rather than a p–n junction, which reduces capacitance and increases switching speed.
A semiconductor diode's behavior in a circuit is given by its current–voltage characteristic. The shape of the curve is determined by the transport of charge carriers through the so-called depletion layer or depletion region that exists at the p–n junction between differing semiconductors. When a p–n junction is first created, conduction-band (mobile) electrons from the N-doped region diffuse into the P-doped region where there is a large population of holes (vacant places for electrons) with which the electrons "recombine". When a mobile electron recombines with a hole, both hole and electron vanish, leaving behind an immobile positively charged donor (dopant) on the N side and negatively charged acceptor (dopant) on the P side. The region around the p–n junction becomes depleted of charge carriers and thus behaves as an insulator.
However, the width of the depletion region (called the depletion width) cannot grow without limit. For each electron–hole pair recombination made, a positively charged dopant ion is left behind in the N-doped region, and a negatively charged dopant ion is created in the P-doped region. As recombination proceeds and more ions are created, an increasing electric field develops through the depletion zone that acts to slow and then finally stop recombination. At this point, there is a "built-in" potential across the depletion zone.
If an external voltage is placed across the diode with the same polarity as the built-in potential, the depletion zone continues to act as an insulator, preventing any significant electric current flow (unless electron–hole pairs are actively being created in the junction by, for instance, light; see photodiode). This is called the reverse bias phenomenon.
However, if the polarity of the external voltage opposes the built-in potential, recombination can once again proceed, resulting in a substantial electric current through the p–n junction (i.e. substantial numbers of electrons and holes recombine at the junction). Thus, if an external voltage greater than and opposite to the built-in voltage is applied, a current will flow and the diode is said to be "turned on" as it has been given an external forward bias.
For simplicity, a diode is commonly said to have a forward threshold voltage, above which it conducts and below which conduction stops. However, this is only an approximation as the forward characteristic is gradual in its current–voltage curve.
At higher currents, the forward voltage drop of the diode increases. A drop of 1 V to 1.5 V is typical at full rated current for power diodes. (See also: Rectifier § Rectifier voltage drop)
A diode's current–voltage characteristic can be approximated by four operating regions. From lower to higher bias voltages, these are:
The Shockley ideal diode equation or the diode law (named after the bipolar junction transistor co-inventor William Bradford Shockley) models the exponential current–voltage (I–V) relationship of diodes in moderate forward or reverse bias. The article Shockley diode equation provides details.
At forward voltages less than the saturation voltage, the voltage versus current characteristic curve of most diodes is not a straight line. The current can be approximated by I = I S e V D / ( n V T ) {\displaystyle I=I_{\text{S}}e^{V_{\text{D}}/(nV_{\text{T}})}} as explained in the Shockley diode equation article.
In detector and mixer applications, the current can be estimated by a Taylor's series. The odd terms can be omitted because they produce frequency components that are outside the pass band of the mixer or detector. Even terms beyond the second derivative usually need not be included because they are small compared to the second order term. The desired current component is approximately proportional to the square of the input voltage, so the response is called square law in this region.
Following the end of forwarding conduction in a p–n type diode, a reverse current can flow for a short time. The device does not attain its blocking capability until the mobile charge in the junction is depleted.
The effect can be significant when switching large currents very quickly. A certain amount of "reverse recovery time" tr (on the order of tens of nanoseconds to a few microseconds) may be required to remove the reverse recovery charge Qr from the diode. During this recovery time, the diode can actually conduct in the reverse direction. This might give rise to a large current in the reverse direction for a short time while the diode is reverse biased. The magnitude of such a reverse current is determined by the operating circuit (i.e., the series resistance) and the diode is said to be in the storage-phase. In certain real-world cases it is important to consider the losses that are incurred by this non-ideal diode effect. However, when the slew rate of the current is not so severe (e.g. Line frequency) the effect can be safely ignored. For most applications, the effect is also negligible for Schottky diodes.
The reverse current ceases abruptly when the stored charge is depleted; this abrupt stop is exploited in step recovery diodes for the generation of extremely short pulses.
Normal (p–n) diodes, which operate as described above, are usually made of doped silicon or germanium. Before the development of silicon power rectifier diodes, cuprous oxide and later selenium was used. Their low efficiency required a much higher forward voltage to be applied (typically 1.4 to 1.7 V per "cell", with multiple cells stacked so as to increase the peak inverse voltage rating for application in high voltage rectifiers), and required a large heat sink (often an extension of the diode's metal substrate), much larger than the later silicon diode of the same current ratings would require. The vast majority of all diodes are the p–n diodes found in CMOS integrated circuits, which include two diodes per pin and many other internal diodes.
The symbol used to represent a particular type of diode in a circuit diagram conveys the general electrical function to the reader. There are alternative symbols for some types of diodes, though the differences are minor. The triangle in the symbols points to the forward direction, i.e. in the direction of conventional current flow.
There are a number of common, standard and manufacturer-driven numbering and coding schemes for diodes; the two most common being the EIA/JEDEC standard and the European Pro Electron standard:
The standardized 1N-series numbering EIA370 system was introduced in the US by EIA/JEDEC (Joint Electron Device Engineering Council) about 1960. Most diodes have a 1-prefix designation (e.g., 1N4003). Among the most popular in this series were: 1N34A/1N270 (germanium signal), 1N914/1N4148 (silicon signal), 1N400x (silicon 1A power rectifier), and 1N580x (silicon 3A power rectifier).
The JIS semiconductor designation system has all semiconductor diode designations starting with "1S".
The European Pro Electron coding system for active components was introduced in 1966 and comprises two letters followed by the part code. The first letter represents the semiconductor material used for the component (A = germanium and B = silicon) and the second letter represents the general function of the part (for diodes, A = low-power/signal, B = variable capacitance, X = multiplier, Y = rectifier and Z = voltage reference); for example:
Other common numbering/coding systems (generally manufacturer-driven) include:
In optics, an equivalent device for the diode but with laser light would be the optical isolator, also known as an optical diode, that allows light to only pass in one direction. It uses a Faraday rotator as the main component.
The first use for the diode was the demodulation of amplitude modulated (AM) radio broadcasts. The history of this discovery is treated in depth in the crystal detector article. In summary, an AM signal consists of alternating positive and negative peaks of a radio carrier wave, whose amplitude or envelope is proportional to the original audio signal. The diode rectifies the AM radio frequency signal, leaving only the positive peaks of the carrier wave. The audio is then extracted from the rectified carrier wave using a simple filter and fed into an audio amplifier or transducer, which generates sound waves via audio speaker.
In microwave and millimeter wave technology, beginning in the 1930s, researchers improved and miniaturized the crystal detector. Point contact diodes (crystal diodes) and Schottky diodes are used in radar, microwave and millimeter wave detectors.
Rectifiers are constructed from diodes, where they are used to convert alternating current (AC) electricity into direct current (DC). Automotive alternators are a common example, where the diode, which rectifies the AC into DC, provides better performance than the commutator or earlier, dynamo. Similarly, diodes are also used in Cockcroft–Walton voltage multipliers to convert AC into higher DC voltages.
Since most electronic circuits can be damaged when the polarity of their power supply inputs are reversed, a series diode is sometimes used to protect against such situations. This concept is known by multiple naming variations that mean the same thing: reverse voltage protection, reverse polarity protection, and reverse battery protection.
Diodes are frequently used to conduct damaging high voltages away from sensitive electronic devices. They are usually reverse-biased (non-conducting) under normal circumstances. When the voltage rises above the normal range, the diodes become forward-biased (conducting). For example, diodes are used in (stepper motor and H-bridge) motor controller and relay circuits to de-energize coils rapidly without the damaging voltage spikes that would otherwise occur. (A diode used in such an application is called a flyback diode). Many integrated circuits also incorporate diodes on the connection pins to prevent external voltages from damaging their sensitive transistors. Specialized diodes are used to protect from over-voltages at higher power (see Diode types above).
Diode-resistor logic constructs AND and OR logic gates. Functional completeness can be achieved by adding an active device to provide inversion (as done with diode-transistor logic).
In addition to light, mentioned above, semiconductor diodes are sensitive to more energetic radiation. In electronics, cosmic rays and other sources of ionizing radiation cause noise pulses and single and multiple bit errors. This effect is sometimes exploited by particle detectors to detect radiation. A single particle of radiation, with thousands or millions of electron volt, s of energy, generates many charge carrier pairs, as its energy is deposited in the semiconductor material. If the depletion layer is large enough to catch the whole shower or to stop a heavy particle, a fairly accurate measurement of the particle's energy can be made, simply by measuring the charge conducted and without the complexity of a magnetic spectrometer, etc. These semiconductor radiation detectors need efficient and uniform charge collection and low leakage current. They are often cooled by liquid nitrogen. For longer-range (about a centimeter) particles, they need a very large depletion depth and large area. For short-range particles, they need any contact or un-depleted semiconductor on at least one surface to be very thin. The back-bias voltages are near breakdown (around a thousand volts per centimeter). Germanium and silicon are common materials. Some of these detectors sense position as well as energy. They have a finite life, especially when detecting heavy particles, because of radiation damage. Silicon and germanium are quite different in their ability to convert gamma rays to electron showers.
Semiconductor detectors for high-energy particles are used in large numbers. Because of energy loss fluctuations, accurate measurement of the energy deposited is of less use.
A diode can be used as a temperature measuring device, since the forward voltage drop across the diode depends on temperature, as in a silicon bandgap temperature sensor. From the Shockley ideal diode equation given above, it might appear that the voltage has a positive temperature coefficient (at a constant current), but usually the variation of the reverse saturation current term is more significant than the variation in the thermal voltage term. Most diodes therefore have a negative temperature coefficient, typically −2 mV/°C for silicon diodes. The temperature coefficient is approximately constant for temperatures above about 20 kelvin. Some graphs are given for 1N400x series, and CY7 cryogenic temperature sensor.
Diodes will prevent currents in unintended directions. To supply power to an electrical circuit during a power failure, the circuit can draw current from a battery. An uninterruptible power supply may use diodes in this way to ensure that the current is only drawn from the battery when necessary. Likewise, small boats typically have two circuits each with their own battery/batteries: one used for engine starting; one used for domestics. Normally, both are charged from a single alternator, and a heavy-duty split-charge diode is used to prevent the higher-charge battery (typically the engine battery) from discharging through the lower-charge battery when the alternator is not running.
Diodes are also used in electronic musical keyboards. To reduce the amount of wiring needed in electronic musical keyboards, these instruments often use keyboard matrix circuits. The keyboard controller scans the rows and columns to determine which note the player has pressed. The problem with matrix circuits is that, when several notes are pressed at once, the current can flow backward through the circuit and trigger "phantom keys" that cause "ghost" notes to play. To avoid triggering unwanted notes, most keyboard matrix circuits have diodes soldered with the switch under each key of the musical keyboard. The same principle is also used for the switch matrix in solid-state pinball machines.
Diodes can be used to limit the positive or negative excursion of a signal to a prescribed voltage.
A diode clamp circuit can take a periodic alternating current signal that oscillates between positive and negative values, and vertically displace it such that either the positive or the negative peaks occur at a prescribed level. The clamper does not restrict the peak-to-peak excursion of the signal, it moves the whole signal up or down so as to place the peaks at the reference level.
The diode's exponential current–voltage relationship is exploited to evaluate exponentiation and its inverse function the logarithm using analog voltage signals (see Operational amplifier applications §§ Exponential output and Logarithmic output).
Diodes are usually referred to as D for diode on PCBs. Sometimes the abbreviation CR for crystal rectifier is used. | [
{
"paragraph_id": 0,
"text": "A diode is a two-terminal electronic component that conducts current primarily in one direction (asymmetric conductance). It has low (ideally zero) resistance in one direction and high (ideally infinite) resistance in the other.",
"title": ""
},
{
"paragraph_id": 1,
"text": "A semiconductor diode, the most commonly used type today, is a crystalline piece of semiconductor material with a p–n junction connected to two electrical terminals. It has an exponential current–voltage characteristic. Semiconductor diodes were the first semiconductor electronic devices. The discovery of asymmetric electrical conduction across the contact between a crystalline mineral and a metal was made by German physicist Ferdinand Braun in 1874. Today, most diodes are made of silicon, but other semiconducting materials such as gallium arsenide and germanium are also used.",
"title": ""
},
{
"paragraph_id": 2,
"text": "The obsolete thermionic diode is a vacuum tube with two electrodes, a heated cathode and a plate, in which electrons can flow in only one direction, from cathode to plate.",
"title": ""
},
{
"paragraph_id": 3,
"text": "Among many uses, diodes are found in rectifiers to convert alternating current (AC) power to direct current (DC), demodulation in radio receivers, and can even be used for logic or as temperature sensors. A common variant of a diode is a light-emitting diode, which is used as electric lighting and status indicators on electronic devices.",
"title": ""
},
{
"paragraph_id": 4,
"text": "The most common function of a diode is to allow an electric current to pass in one direction (called the diode's forward direction), while blocking it in the opposite direction (the reverse direction). Therefore, the diode can be viewed as an electronic version of a check valve. This unidirectional behavior is called rectification and is used to convert alternating current (AC) to direct current (DC). As rectifiers, diodes can be used for such tasks as extracting modulation from radio signals in radio receivers.",
"title": "Main functions"
},
{
"paragraph_id": 5,
"text": "However, diodes can have more complicated behavior than this simple on–off action, because of their nonlinear current–voltage characteristics. For instance, a diode's forward-direction voltage drop varies only a little with the current, and is more so a function of temperature; this effect can be used as a temperature sensor or as a voltage reference. And its high resistance to current flowing in the reverse direction suddenly drops to a low resistance when the reverse voltage across the diode reaches a value called the breakdown voltage. Semiconductor diodes in the forward direction also need to surpass a threshold voltage before being able to conduct electricity.",
"title": "Main functions"
},
{
"paragraph_id": 6,
"text": "A semiconductor diode's current–voltage characteristic can be tailored by selecting the semiconductor materials and the doping impurities introduced into the materials during manufacture. These techniques are used to create special-purpose diodes that perform many different functions. For example, diodes are used to regulate voltage (Zener diodes), to protect circuits from high voltage surges (avalanche diodes), to electronically tune radio and TV receivers (varactor diodes), to generate radio-frequency oscillations (tunnel diodes, Gunn diodes, IMPATT diodes), and to produce light (light-emitting diodes). Tunnel, Gunn and IMPATT diodes exhibit negative resistance, which is useful in microwave and switching circuits.",
"title": "Main functions"
},
{
"paragraph_id": 7,
"text": "Diodes, both vacuum and semiconductor, can be used as shot-noise generators.",
"title": "Main functions"
},
{
"paragraph_id": 8,
"text": "Thermionic (vacuum-tube) diodes and solid-state (semiconductor) diodes were developed separately, at approximately the same time, in the early 1900s, as radio receiver detectors. Until the 1950s, vacuum diodes were used more frequently in radios because the early point-contact semiconductor diodes were less stable. In addition, most receiving sets had vacuum tubes for amplification that could easily have the thermionic diodes included in the tube (for example the 12SQ7 double diode triode), and vacuum-tube rectifiers and gas-filled rectifiers were capable of handling some high-voltage/high-current rectification tasks better than the semiconductor diodes (such as selenium rectifiers) that were available at that time.",
"title": "History"
},
{
"paragraph_id": 9,
"text": "In 1873, Frederick Guthrie observed that a grounded, white-hot metal ball brought in close proximity to an electroscope would discharge a positively charged electroscope, but not a negatively charged electroscope. In 1880, Thomas Edison observed unidirectional current between heated and unheated elements in a bulb, later called Edison effect, and was granted a patent on application of the phenomenon for use in a DC voltmeter. About 20 years later, John Ambrose Fleming (scientific adviser to the Marconi Company and former Edison employee) realized that the Edison effect could be used as a radio detector. Fleming patented the first true thermionic diode, the Fleming valve, in Britain on 16 November 1904 (followed by U.S. Patent 803,684 in November 1905). Throughout the vacuum tube era, valve diodes were used in almost all electronics such as radios, televisions, sound systems, and instrumentation. They slowly lost market share beginning in the late 1940s due to selenium rectifier technology and then to semiconductor diodes during the 1960s. Today they are still used in a few high power applications where their ability to withstand transient voltages and their robustness gives them an advantage over semiconductor devices, and in musical instrument and audiophile applications.",
"title": "History"
},
{
"paragraph_id": 10,
"text": "In 1874, German scientist Karl Ferdinand Braun discovered the \"unilateral conduction\" across a contact between a metal and a mineral. Indian scientist Jagadish Chandra Bose was the first to use a crystal for detecting radio waves in 1894. The crystal detector was developed into a practical device for wireless telegraphy by Greenleaf Whittier Pickard, who invented a silicon crystal detector in 1903 and received a patent for it on 20 November 1906. Other experimenters tried a variety of other minerals as detectors. Semiconductor principles were unknown to the developers of these early rectifiers. During the 1930s understanding of physics advanced and in the mid 1930s researchers at Bell Telephone Laboratories recognized the potential of the crystal detector for application in microwave technology. Researchers at Bell Labs, Western Electric, MIT, Purdue and in the UK intensively developed point-contact diodes (crystal rectifiers or crystal diodes) during World War II for application in radar. After World War II, AT&T used these in its microwave towers that criss-crossed the United States, and many radar sets use them even in the 21st century. In 1946, Sylvania began offering the 1N34 crystal diode. During the early 1950s, junction diodes were developed.",
"title": "History"
},
{
"paragraph_id": 11,
"text": "In 2022, the first superconducting diode effect without an external magnetic field was realized.",
"title": "History"
},
{
"paragraph_id": 12,
"text": "At the time of their invention, asymmetrical conduction devices were known as rectifiers. In 1919, the year tetrodes were invented, William Henry Eccles coined the term diode from the Greek roots di (from δί), meaning 'two', and ode (from οδός), meaning 'path'. The word diode however was already in use, as were triode, tetrode, pentode, hexode, as terms of multiplex telegraphy.",
"title": "Etymology"
},
{
"paragraph_id": 13,
"text": "Although all diodes rectify, \"rectifier\" usually applies to diodes used for power supply, to differentiate them from diodes intended for small signal circuits.",
"title": "Etymology"
},
{
"paragraph_id": 14,
"text": "A thermionic diode is a thermionic-valve device consisting of a sealed, evacuated glass or metal envelope containing two electrodes: a cathode and a plate. The cathode is either indirectly heated or directly heated. If indirect heating is employed, a heater is included in the envelope.",
"title": "Vacuum tube diodes"
},
{
"paragraph_id": 15,
"text": "In operation, the cathode is heated to red heat, around 800–1,000 °C (1,470–1,830 °F). A directly heated cathode is made of tungsten wire and is heated by a current passed through it from an external voltage source. An indirectly heated cathode is heated by infrared radiation from a nearby heater that is formed of Nichrome wire and supplied with current provided by an external voltage source.",
"title": "Vacuum tube diodes"
},
{
"paragraph_id": 16,
"text": "The operating temperature of the cathode causes it to release electrons into the vacuum, a process called thermionic emission. The cathode is coated with oxides of alkaline earth metals, such as barium and strontium oxides. These have a low work function, meaning that they more readily emit electrons than would the uncoated cathode.",
"title": "Vacuum tube diodes"
},
{
"paragraph_id": 17,
"text": "The plate, not being heated, does not emit electrons; but is able to absorb them.",
"title": "Vacuum tube diodes"
},
{
"paragraph_id": 18,
"text": "The alternating voltage to be rectified is applied between the cathode and the plate. When the plate voltage is positive with respect to the cathode, the plate electrostatically attracts the electrons from the cathode, so a current of electrons flows through the tube from cathode to plate. When the plate voltage is negative with respect to the cathode, no electrons are emitted by the plate, so no current can pass from the plate to the cathode.",
"title": "Vacuum tube diodes"
},
{
"paragraph_id": 19,
"text": "Point-contact diodes were developed starting in the 1930s, out of the early crystal detector technology, and are now generally used in the 3 to 30 gigahertz range. Point-contact diodes use a small diameter metal wire in contact with a semiconductor crystal, and are of either non-welded contact type or welded contact type. Non-welded contact construction utilizes the Schottky barrier principle. The metal side is the pointed end of a small diameter wire that is in contact with the semiconductor crystal. In the welded contact type, a small P region is formed in the otherwise N-type crystal around the metal point during manufacture by momentarily passing a relatively large current through the device. Point contact diodes generally exhibit lower capacitance, higher forward resistance and greater reverse leakage than junction diodes.",
"title": "Semiconductor diodes"
},
{
"paragraph_id": 20,
"text": "A p–n junction diode is made of a crystal of semiconductor, usually silicon, but germanium and gallium arsenide are also used. Impurities are added to it to create a region on one side that contains negative charge carriers (electrons), called an n-type semiconductor, and a region on the other side that contains positive charge carriers (holes), called a p-type semiconductor. When the n-type and p-type materials are attached together, a momentary flow of electrons occurs from the n to the p side resulting in a third region between the two where no charge carriers are present. This region is called the depletion region because there are no charge carriers (neither electrons nor holes) in it. The diode's terminals are attached to the n-type and p-type regions. The boundary between these two regions called a p–n junction, is where the action of the diode takes place. When a sufficiently higher electrical potential is applied to the P side (the anode) than to the N side (the cathode), it allows electrons to flow through the depletion region from the N-type side to the P-type side. The junction does not allow the flow of electrons in the opposite direction when the potential is applied in reverse, creating, in a sense, an electrical check valve.",
"title": "Semiconductor diodes"
},
{
"paragraph_id": 21,
"text": "Another type of junction diode, the Schottky diode, is formed from a metal–semiconductor junction rather than a p–n junction, which reduces capacitance and increases switching speed.",
"title": "Semiconductor diodes"
},
{
"paragraph_id": 22,
"text": "A semiconductor diode's behavior in a circuit is given by its current–voltage characteristic. The shape of the curve is determined by the transport of charge carriers through the so-called depletion layer or depletion region that exists at the p–n junction between differing semiconductors. When a p–n junction is first created, conduction-band (mobile) electrons from the N-doped region diffuse into the P-doped region where there is a large population of holes (vacant places for electrons) with which the electrons \"recombine\". When a mobile electron recombines with a hole, both hole and electron vanish, leaving behind an immobile positively charged donor (dopant) on the N side and negatively charged acceptor (dopant) on the P side. The region around the p–n junction becomes depleted of charge carriers and thus behaves as an insulator.",
"title": "Semiconductor diodes"
},
{
"paragraph_id": 23,
"text": "However, the width of the depletion region (called the depletion width) cannot grow without limit. For each electron–hole pair recombination made, a positively charged dopant ion is left behind in the N-doped region, and a negatively charged dopant ion is created in the P-doped region. As recombination proceeds and more ions are created, an increasing electric field develops through the depletion zone that acts to slow and then finally stop recombination. At this point, there is a \"built-in\" potential across the depletion zone.",
"title": "Semiconductor diodes"
},
{
"paragraph_id": 24,
"text": "If an external voltage is placed across the diode with the same polarity as the built-in potential, the depletion zone continues to act as an insulator, preventing any significant electric current flow (unless electron–hole pairs are actively being created in the junction by, for instance, light; see photodiode). This is called the reverse bias phenomenon.",
"title": "Semiconductor diodes"
},
{
"paragraph_id": 25,
"text": "However, if the polarity of the external voltage opposes the built-in potential, recombination can once again proceed, resulting in a substantial electric current through the p–n junction (i.e. substantial numbers of electrons and holes recombine at the junction). Thus, if an external voltage greater than and opposite to the built-in voltage is applied, a current will flow and the diode is said to be \"turned on\" as it has been given an external forward bias.",
"title": "Semiconductor diodes"
},
{
"paragraph_id": 26,
"text": "For simplicity, a diode is commonly said to have a forward threshold voltage, above which it conducts and below which conduction stops. However, this is only an approximation as the forward characteristic is gradual in its current–voltage curve.",
"title": "Semiconductor diodes"
},
{
"paragraph_id": 27,
"text": "At higher currents, the forward voltage drop of the diode increases. A drop of 1 V to 1.5 V is typical at full rated current for power diodes. (See also: Rectifier § Rectifier voltage drop)",
"title": "Semiconductor diodes"
},
{
"paragraph_id": 28,
"text": "A diode's current–voltage characteristic can be approximated by four operating regions. From lower to higher bias voltages, these are:",
"title": "Semiconductor diodes"
},
{
"paragraph_id": 29,
"text": "The Shockley ideal diode equation or the diode law (named after the bipolar junction transistor co-inventor William Bradford Shockley) models the exponential current–voltage (I–V) relationship of diodes in moderate forward or reverse bias. The article Shockley diode equation provides details.",
"title": "Semiconductor diodes"
},
{
"paragraph_id": 30,
"text": "At forward voltages less than the saturation voltage, the voltage versus current characteristic curve of most diodes is not a straight line. The current can be approximated by I = I S e V D / ( n V T ) {\\displaystyle I=I_{\\text{S}}e^{V_{\\text{D}}/(nV_{\\text{T}})}} as explained in the Shockley diode equation article.",
"title": "Semiconductor diodes"
},
{
"paragraph_id": 31,
"text": "In detector and mixer applications, the current can be estimated by a Taylor's series. The odd terms can be omitted because they produce frequency components that are outside the pass band of the mixer or detector. Even terms beyond the second derivative usually need not be included because they are small compared to the second order term. The desired current component is approximately proportional to the square of the input voltage, so the response is called square law in this region.",
"title": "Semiconductor diodes"
},
{
"paragraph_id": 32,
"text": "Following the end of forwarding conduction in a p–n type diode, a reverse current can flow for a short time. The device does not attain its blocking capability until the mobile charge in the junction is depleted.",
"title": "Semiconductor diodes"
},
{
"paragraph_id": 33,
"text": "The effect can be significant when switching large currents very quickly. A certain amount of \"reverse recovery time\" tr (on the order of tens of nanoseconds to a few microseconds) may be required to remove the reverse recovery charge Qr from the diode. During this recovery time, the diode can actually conduct in the reverse direction. This might give rise to a large current in the reverse direction for a short time while the diode is reverse biased. The magnitude of such a reverse current is determined by the operating circuit (i.e., the series resistance) and the diode is said to be in the storage-phase. In certain real-world cases it is important to consider the losses that are incurred by this non-ideal diode effect. However, when the slew rate of the current is not so severe (e.g. Line frequency) the effect can be safely ignored. For most applications, the effect is also negligible for Schottky diodes.",
"title": "Semiconductor diodes"
},
{
"paragraph_id": 34,
"text": "The reverse current ceases abruptly when the stored charge is depleted; this abrupt stop is exploited in step recovery diodes for the generation of extremely short pulses.",
"title": "Semiconductor diodes"
},
{
"paragraph_id": 35,
"text": "Normal (p–n) diodes, which operate as described above, are usually made of doped silicon or germanium. Before the development of silicon power rectifier diodes, cuprous oxide and later selenium was used. Their low efficiency required a much higher forward voltage to be applied (typically 1.4 to 1.7 V per \"cell\", with multiple cells stacked so as to increase the peak inverse voltage rating for application in high voltage rectifiers), and required a large heat sink (often an extension of the diode's metal substrate), much larger than the later silicon diode of the same current ratings would require. The vast majority of all diodes are the p–n diodes found in CMOS integrated circuits, which include two diodes per pin and many other internal diodes.",
"title": "Semiconductor diodes"
},
{
"paragraph_id": 36,
"text": "The symbol used to represent a particular type of diode in a circuit diagram conveys the general electrical function to the reader. There are alternative symbols for some types of diodes, though the differences are minor. The triangle in the symbols points to the forward direction, i.e. in the direction of conventional current flow.",
"title": "Semiconductor diodes"
},
{
"paragraph_id": 37,
"text": "There are a number of common, standard and manufacturer-driven numbering and coding schemes for diodes; the two most common being the EIA/JEDEC standard and the European Pro Electron standard:",
"title": "Semiconductor diodes"
},
{
"paragraph_id": 38,
"text": "The standardized 1N-series numbering EIA370 system was introduced in the US by EIA/JEDEC (Joint Electron Device Engineering Council) about 1960. Most diodes have a 1-prefix designation (e.g., 1N4003). Among the most popular in this series were: 1N34A/1N270 (germanium signal), 1N914/1N4148 (silicon signal), 1N400x (silicon 1A power rectifier), and 1N580x (silicon 3A power rectifier).",
"title": "Semiconductor diodes"
},
{
"paragraph_id": 39,
"text": "The JIS semiconductor designation system has all semiconductor diode designations starting with \"1S\".",
"title": "Semiconductor diodes"
},
{
"paragraph_id": 40,
"text": "The European Pro Electron coding system for active components was introduced in 1966 and comprises two letters followed by the part code. The first letter represents the semiconductor material used for the component (A = germanium and B = silicon) and the second letter represents the general function of the part (for diodes, A = low-power/signal, B = variable capacitance, X = multiplier, Y = rectifier and Z = voltage reference); for example:",
"title": "Semiconductor diodes"
},
{
"paragraph_id": 41,
"text": "Other common numbering/coding systems (generally manufacturer-driven) include:",
"title": "Semiconductor diodes"
},
{
"paragraph_id": 42,
"text": "In optics, an equivalent device for the diode but with laser light would be the optical isolator, also known as an optical diode, that allows light to only pass in one direction. It uses a Faraday rotator as the main component.",
"title": "Related devices"
},
{
"paragraph_id": 43,
"text": "The first use for the diode was the demodulation of amplitude modulated (AM) radio broadcasts. The history of this discovery is treated in depth in the crystal detector article. In summary, an AM signal consists of alternating positive and negative peaks of a radio carrier wave, whose amplitude or envelope is proportional to the original audio signal. The diode rectifies the AM radio frequency signal, leaving only the positive peaks of the carrier wave. The audio is then extracted from the rectified carrier wave using a simple filter and fed into an audio amplifier or transducer, which generates sound waves via audio speaker.",
"title": "Applications"
},
{
"paragraph_id": 44,
"text": "In microwave and millimeter wave technology, beginning in the 1930s, researchers improved and miniaturized the crystal detector. Point contact diodes (crystal diodes) and Schottky diodes are used in radar, microwave and millimeter wave detectors.",
"title": "Applications"
},
{
"paragraph_id": 45,
"text": "Rectifiers are constructed from diodes, where they are used to convert alternating current (AC) electricity into direct current (DC). Automotive alternators are a common example, where the diode, which rectifies the AC into DC, provides better performance than the commutator or earlier, dynamo. Similarly, diodes are also used in Cockcroft–Walton voltage multipliers to convert AC into higher DC voltages.",
"title": "Applications"
},
{
"paragraph_id": 46,
"text": "Since most electronic circuits can be damaged when the polarity of their power supply inputs are reversed, a series diode is sometimes used to protect against such situations. This concept is known by multiple naming variations that mean the same thing: reverse voltage protection, reverse polarity protection, and reverse battery protection.",
"title": "Applications"
},
{
"paragraph_id": 47,
"text": "Diodes are frequently used to conduct damaging high voltages away from sensitive electronic devices. They are usually reverse-biased (non-conducting) under normal circumstances. When the voltage rises above the normal range, the diodes become forward-biased (conducting). For example, diodes are used in (stepper motor and H-bridge) motor controller and relay circuits to de-energize coils rapidly without the damaging voltage spikes that would otherwise occur. (A diode used in such an application is called a flyback diode). Many integrated circuits also incorporate diodes on the connection pins to prevent external voltages from damaging their sensitive transistors. Specialized diodes are used to protect from over-voltages at higher power (see Diode types above).",
"title": "Applications"
},
{
"paragraph_id": 48,
"text": "Diode-resistor logic constructs AND and OR logic gates. Functional completeness can be achieved by adding an active device to provide inversion (as done with diode-transistor logic).",
"title": "Applications"
},
{
"paragraph_id": 49,
"text": "In addition to light, mentioned above, semiconductor diodes are sensitive to more energetic radiation. In electronics, cosmic rays and other sources of ionizing radiation cause noise pulses and single and multiple bit errors. This effect is sometimes exploited by particle detectors to detect radiation. A single particle of radiation, with thousands or millions of electron volt, s of energy, generates many charge carrier pairs, as its energy is deposited in the semiconductor material. If the depletion layer is large enough to catch the whole shower or to stop a heavy particle, a fairly accurate measurement of the particle's energy can be made, simply by measuring the charge conducted and without the complexity of a magnetic spectrometer, etc. These semiconductor radiation detectors need efficient and uniform charge collection and low leakage current. They are often cooled by liquid nitrogen. For longer-range (about a centimeter) particles, they need a very large depletion depth and large area. For short-range particles, they need any contact or un-depleted semiconductor on at least one surface to be very thin. The back-bias voltages are near breakdown (around a thousand volts per centimeter). Germanium and silicon are common materials. Some of these detectors sense position as well as energy. They have a finite life, especially when detecting heavy particles, because of radiation damage. Silicon and germanium are quite different in their ability to convert gamma rays to electron showers.",
"title": "Applications"
},
{
"paragraph_id": 50,
"text": "Semiconductor detectors for high-energy particles are used in large numbers. Because of energy loss fluctuations, accurate measurement of the energy deposited is of less use.",
"title": "Applications"
},
{
"paragraph_id": 51,
"text": "A diode can be used as a temperature measuring device, since the forward voltage drop across the diode depends on temperature, as in a silicon bandgap temperature sensor. From the Shockley ideal diode equation given above, it might appear that the voltage has a positive temperature coefficient (at a constant current), but usually the variation of the reverse saturation current term is more significant than the variation in the thermal voltage term. Most diodes therefore have a negative temperature coefficient, typically −2 mV/°C for silicon diodes. The temperature coefficient is approximately constant for temperatures above about 20 kelvin. Some graphs are given for 1N400x series, and CY7 cryogenic temperature sensor.",
"title": "Applications"
},
{
"paragraph_id": 52,
"text": "Diodes will prevent currents in unintended directions. To supply power to an electrical circuit during a power failure, the circuit can draw current from a battery. An uninterruptible power supply may use diodes in this way to ensure that the current is only drawn from the battery when necessary. Likewise, small boats typically have two circuits each with their own battery/batteries: one used for engine starting; one used for domestics. Normally, both are charged from a single alternator, and a heavy-duty split-charge diode is used to prevent the higher-charge battery (typically the engine battery) from discharging through the lower-charge battery when the alternator is not running.",
"title": "Applications"
},
{
"paragraph_id": 53,
"text": "Diodes are also used in electronic musical keyboards. To reduce the amount of wiring needed in electronic musical keyboards, these instruments often use keyboard matrix circuits. The keyboard controller scans the rows and columns to determine which note the player has pressed. The problem with matrix circuits is that, when several notes are pressed at once, the current can flow backward through the circuit and trigger \"phantom keys\" that cause \"ghost\" notes to play. To avoid triggering unwanted notes, most keyboard matrix circuits have diodes soldered with the switch under each key of the musical keyboard. The same principle is also used for the switch matrix in solid-state pinball machines.",
"title": "Applications"
},
{
"paragraph_id": 54,
"text": "Diodes can be used to limit the positive or negative excursion of a signal to a prescribed voltage.",
"title": "Applications"
},
{
"paragraph_id": 55,
"text": "A diode clamp circuit can take a periodic alternating current signal that oscillates between positive and negative values, and vertically displace it such that either the positive or the negative peaks occur at a prescribed level. The clamper does not restrict the peak-to-peak excursion of the signal, it moves the whole signal up or down so as to place the peaks at the reference level.",
"title": "Applications"
},
{
"paragraph_id": 56,
"text": "The diode's exponential current–voltage relationship is exploited to evaluate exponentiation and its inverse function the logarithm using analog voltage signals (see Operational amplifier applications §§ Exponential output and Logarithmic output).",
"title": "Applications"
},
{
"paragraph_id": 57,
"text": "Diodes are usually referred to as D for diode on PCBs. Sometimes the abbreviation CR for crystal rectifier is used.",
"title": "Abbreviations"
}
] | A diode is a two-terminal electronic component that conducts current primarily in one direction. It has low resistance in one direction and high resistance in the other. A semiconductor diode, the most commonly used type today, is a crystalline piece of semiconductor material with a p–n junction connected to two electrical terminals. It has an exponential current–voltage characteristic. Semiconductor diodes were the first semiconductor electronic devices. The discovery of asymmetric electrical conduction across the contact between a crystalline mineral and a metal was made by German physicist Ferdinand Braun in 1874. Today, most diodes are made of silicon, but other semiconducting materials such as gallium arsenide and germanium are also used. The obsolete thermionic diode is a vacuum tube with two electrodes, a heated cathode and a plate, in which electrons can flow in only one direction, from cathode to plate. Among many uses, diodes are found in rectifiers to convert alternating current (AC) power to direct current (DC), demodulation in radio receivers, and can even be used for logic or as temperature sensors. A common variant of a diode is a light-emitting diode, which is used as electric lighting and status indicators on electronic devices. | 2001-09-10T03:09:34Z | 2023-10-28T13:17:28Z | [
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8,256 | Drexel University | Drexel University is a private research university with its main campus in Philadelphia, Pennsylvania. Drexel's undergraduate school was founded in 1891 by Anthony J. Drexel, a financier and philanthropist. Founded as Drexel Institute of Art, Science and Industry, it was renamed Drexel Institute of Technology in 1936, before assuming its current name in 1970.
As of 2020, more than 24,000 students were enrolled in over 70 undergraduate programs and more than 100 master's, doctoral, and professional programs at the university.
Drexel's cooperative education program (co-op) is a unique aspect of the school's degree programs, offering students the opportunity to gain up to 18 months of paid, full-time work experience in a field relevant to their undergraduate major or graduate degree program prior to graduation.
Drexel University was founded in 1891 as the Drexel Institute of Art, Science and Industry by Anthony J. Drexel, a Philadelphia financier and philanthropist. The original mission of the institution was to provide educational opportunities in the "practical arts and sciences" for women and men of all backgrounds.
In 1936, the institution was renamed as the Drexel Institute of Technology; in 1970, it was renamed again as the Drexel Institute of Technology. It gained university status, and was finally named Drexel University.
Despite changes during its first century, the university has remained a privately controlled, non-sectarian, coeducational center of higher learning committed to practical education and hands-on experience in an occupational setting. The central aspect of Drexel University's focus on career preparation, in the form of its cooperative education program, was introduced in 1919. Participating students alternate periods of classroom-based study with periods of full-time, practical work experience related to one's academic major and career interests.
Between 1995 and 2009, Drexel University underwent a period of significant change to its programs, enrollment, and facilities under the leadership of Dr. Constantine Papadakis, the university's president during that time. Papadakis oversaw Drexel's largest expansion in its history, with a 471 percent increase in its endowment and a 102 percent increase in student enrollment. He oversaw improved performance in collegiate rankings, the implementation of a more selective approach to admissions, and a more rigorous academic program at all levels. In 2007, Drexel was the host of the 2008 Democratic presidential candidate debate in Philadelphia, televised by MSNBC.
In 2002, Drexel University acquired and assumed management of the former MCP Hahnemann University, creating the Drexel University College of Medicine. In 2006, the university established the Thomas R. Kline School of Law, and in 2011 the School of Law achieved full accreditation by the American Bar Association.
Constantine Papadakis died of pneumonia in April 2009 while still employed as the university's president. His successor, John Anderson Fry, was previously the president of Franklin & Marshall College and executive vice president of the University of Pennsylvania.
Under Fry's leadership, Drexel has continued its expansion, including the July 2011 acquisition of The Academy of Natural Sciences.
The College of Arts and Sciences was formed in 1990 when Drexel merged the two existing College of Sciences and College of Humanities together.
The College of Media Arts and Design "fosters the study, exploration and management of the arts: media, design, the performing and visual". The college offers 18 undergraduate programs and nine graduate programs, in modern art and design fields that range from architecture, graphic design and dance to fashion design and television management. Its wide range of programs has helped the college earn full accreditation from the National Association of Schools of Art and Design, the National Architectural Accrediting Board, and the Council for Interior Design Accreditation.
The Bennett S. LeBow College of Business history dates to the founding in 1891 of the Drexel Institute, that later became Drexel University, and of its Business Department in 1896. Today LeBow offers thirteen undergraduate majors, eight graduate programs, and two doctoral programs; 22 percent of Drexel University's undergraduate students are enrolled in a LeBow College of Business program.
The LeBow College of Business has been ranked as the 38th best private business school in the nation. Its online MBA program is ranked 14th in the world by the Financial Times; the publication also ranks the undergraduate business program at LeBow as 19th in the United States. The part-time MBA program ranks 1st in academic quality in the 2015 edition of Business Insider's rankings. Undergraduate and graduate entrepreneurship programs are ranked 19th in the country by the Princeton Review. Lebow College of Business's Master of Finance program is ranked 101st in the world by the 2020 QS World University Rankings.
Economics programs at the LeBow College of Business are housed within the School of Economics. In addition to the undergraduate program in economics, the school is home to an M.S. in Economics program as well as a PhD program in economics. Faculty members in the School of Economics have been published in the American Economic Review, RAND Journal of Economics, and Review of Economics and Statistics. The school has been ranked among the best in the world for its extensive research into matters of international trade.
Drexel's College of Engineering is one of its oldest and largest academic colleges, and served as the original focus of the career-oriented school upon its founding in 1891. The College of Engineering is home to several notable alumni, including two astronauts; financier Bennett S. LeBow, for whom the university's College of Business is named; and Paul Baran, inventor of the packet-switched network. Today, Drexel University's College of Engineering, which is home to 19 percent of the undergraduate student body, is known for creating the world's first engineering degree in appropriate technology. The college is also one of only 17 U.S. universities to offer a bachelor's degree in architectural engineering, and only one of five private institutions to do so.
The 2009 edition of U.S. News & World Report ranks the undergraduate engineering program as the 52nd-best in the nation.
The engineering curriculum used by the school was originally called E4 (Enhanced Educational Experience for Engineers) which was established in 1986 and funded in part by the Engineering Directorate of the National Science Foundation.
In 1988, the program evolved into tDEC (the Drexel Engineering Curriculum) which is composed of two full years of rigorous core engineering courses which encompass the freshman and sophomore years of the engineering student. The College of Engineering hasn't used the tDEC curriculum since approximately 2005.
The College of Computing and Informatics is a recent addition to Drexel University, though its programs have been offered to students for many years. The college was formed by the consolidation of the former College of Information Science & Technology (often called the "iSchool"), the Department of Computer Science, and the Computing and Security Technology program. Undergraduate and graduate programs in computer science, software engineering, data science, information systems, and computer security are offered by the college.
The Drexel University College of Medicine was added to the colleges and schools of the university in 2002, having been formed upon the acquisition of MCP Hahnemann University. In addition to its M.D. program, the College of Medicine offers more than 40 graduate programs in its Graduate School of Biomedical Sciences and Professional Studies.
The Graduate School of Biomedical Sciences and Professional studies offers both Master of Science and Doctor of Philosophy degree programs in fields like biochemistry, biotechnology, clinical research, and forensic science. The school also serves as the center for biomedical research at Drexel University.
Founded in 1961 as the United States' first Biomedical Engineering and Science Institute, the School of Biomedical Engineering, Science and Health Systems focuses on the emerging field of biomedical science at the undergraduate, graduate, and doctoral levels. Primary research areas within the school include bioinformatics, biomechanics, biomaterials, neuroengineering, and cardiovascular engineering.
Formed in 2002 along with the College of Medicine, Drexel's College of Nursing and Health Professions offers more than 25 programs to undergraduate and graduate students in the fields of nursing, nutrition, health sciences, health services, and radiologic technology. The college's research into matters of nutrition and rehabilitation have garnered approximately $2.9 million in external research funding on an annual basis. The physician assistant program at Drexel's College of Nursing and Health Professions is ranked in the top 15 such programs in the United States; its anesthesia programs and physical therapy programs are, respectively, ranked as top-50 programs nationwide.
Established in 1892, the department now known as the College of Professional Studies has focused exclusively on educational programs and pursuits for nontraditional adult learners. Today, the Goodwin College of Professional Studies offers several options designed for adult learners at all stages of career and educational development. Bachelor of Science degree completion programs are offered in part-time evening or weekend formats; graduate programs and doctoral programs are offered at the graduate level, as are self-paced "continuing education" courses and nearly a dozen self-paced certification programs.
The Pennoni Honors College, named for Drexel alumnus and trustee Dr. C.R. "Chuck" Pennoni '63, '66, Hon. '92, and his wife Annette, recognizes and promotes excellence among Drexel students. Students admitted to the Honors College live together and take many of the same classes; the college provides these students with access to unique cultural and social activities and a unique guest speaker series. Students are also involved in the university's Honors Student Advisory Committee and have the opportunity to take part in Drexel's "Alternative Spring Break", an international study tour held each spring.
Upon its founding in 2006, the Thomas R. Kline School of Law, originally known as the Earle Mack School of Law, was the first law school founded in Philadelphia in more than three decades. The School of Law offers L.L.M. and Master of Legal Studies degrees, in addition to the flagship Juris Doctor program, and uniquely offers cooperative education as part of its curriculum across all programs. In 2015, Bloomberg Business ranked the Kline School of Law as the second most underrated law school in the United States.
One of the oldest schools within Drexel University, the modern School of Education dates back to the 1891 founding of the school. Originally, the Department of Education offered teacher training to women as one of its original, career-focused degree programs. Today, the School of Education offers a coeducational approach to teacher training at the elementary and secondary levels for undergraduates. Other undergraduate programs include those focused on the intersection between learning and technology, teacher certification for non-education majors, and a minor in education for students with an interest in instruction. Graduate degrees offered by the School of Education include those in administration and leadership, special education, higher education, mathematics education, international education, and educational creativity and innovation. Doctoral degrees are offered in educational leadership and learning technologies.
The School of Public Health states that its mission is to "provide education, conduct research, and partner with communities and organizations to improve the health of populations". To that end, the school offers both a B.S. and a minor in public health for undergraduate students as well as several options for students pursuing graduate and doctoral degrees in the field. At the graduate level, the Dornsife School offers both a Master of Public Health and an Executive Master of Public Health, as well as an M.S. in biostatistics and an M.S. in epidemiology. Two Doctor of Public Health degrees are also offered, as isa Doctor of Philosophy in epidemiology. The school's graduate and doctoral students are heavily invested in the research activities of the Dornsife School of Public Health, which has helped the school attract annual funding for its four research centers.
The Center for Hospitality and Sport Management was formed in 2013, in an effort to house and consolidate academic programs in hospitality, tourism management, the culinary arts, and sport management. Academic programs combine the unique skills required of the sports and hospitality industries with the principles and curriculum espoused by the management programs within Drexel's LeBow College of Business.
Focusing specifically on the skills required to successfully start and launch a business, the Charles D. Close School of Entrepreneurship is the first and only freestanding school of entrepreneurship in the United States. Undergraduate students take part in a B.A. program in entrepreneurship and innovation, while graduate students a combined Master of Science degree in biomedicine and entrepreneurship. Minors in entrepreneurship are also offered to undergraduate students.
Housed within the Close School is the Baiada Institute for Entrepreneurship. The institute serves as an incubator for Drexel student startups, providing resources and mentorships to students and some post-graduates who are starting their own business while enrolled in one of the Close School's degree programs or academic minors.
Drexel University launched its first Internet-based education program, a master's degree in Library & Information Science, in 1996. In 2001, Drexel created its wholly owned, for-profit online education subsidiary, Drexel e-Learning, Inc., better known as Drexel University Online. It was announced in October 2013 that Drexel University Online would no longer be a for-profit venture, but rather become an internal division within the university to better serve its online student population. Although headquartered in Philadelphia, Drexel announced a new Washington, D.C., location in December 2012 to serve as both an academic and outreach center, catering to the online student population.
Drexel University Online founded the National Distance Learning Week, in conjunction with the United States Distance Learning Association, in 2007. In September 2010, Drexel University Online received the Sloan-C award for institution-wide excellence in online education indicating that it had exceptional programs of "demonstrably high quality" at the regional and national levels and across disciplines. Drexel University Online won the 2008 United States Distance Learning Association's Best Practices Awards for Distance Learning Programming. In 2007, the online education subsidiary had a revenue of $40 million. In March 2013, Drexel Online had more than 7,000 unique students from all 50 states and more than 20 countries pursuing a bachelor's, master's, or certificate. As of December 2013, Drexel University Online offers more than 100 fully accredited master's degrees, bachelor's degrees and certificate programs.
Drexel's longstanding cooperative education, or "co-op" program is one of the largest and oldest in the United States. Drexel has a fully internet-based job database, where students can submit résumés and request interviews with any of the thousands of companies that offer positions. Students also have the option of obtaining a co-op via independent search. A student graduating from Drexel's 5-year degree program typically has a total of 18 months of co-op with up to three different companies. The majority of co-ops are paid, averaging $18,720 per 6-month period, however this figure changes with major. About one third of Drexel graduates are offered full-time positions by their co-op employers right after graduation.
Drexel is classified among "R1: Doctoral Universities – Very High Research Activity". The university was ranked 51st in the 2018 edition of the "Top 100 Worldwide Universities Granted U.S. Utility Patents" list released by the National Academy of Inventors and the Intellectual Property Owners Association.
In its 2024 rankings, U.S. News & World Report ranked Drexel tied for 98th among national universities in the United States, tied for 18th in the "Most Innovative Schools" category, 95th in "Best Value Schools", and tied for 273rd in "Top Performers on Social Mobility.
In its 2018 rankings, Times Higher Education World University Rankings and The Wall Street Journal ranked Drexel 74th among national universities and 351st-400th among international universities.
In its 2018 rankings, Forbes ranked Drexel 24th among STEM universities. In 2019, it also ranked Drexel 226th among 650 national universities, liberal arts colleges and service academies, 120th among research universities, 154th among private universities, and 96th among universities in the Northeast.
In 2016, Bloomberg Businessweek ranked the undergraduate business program 78th in the country. In 2014, Business Insider ranked Drexel's graduate business school 19th in the country for networking.
Drexel University's programs are divided across three Philadelphia-area campuses: the University City Campus, the Center City Campus and the Queen Lane College of Medicine Campus.
The 77-acre (31 ha) University City Main Campus of Drexel University is located just west of the Schuylkill River in the University City district of Philadelphia. It is Drexel's largest and oldest campus; the campus contains the university's administrative offices and serves as the main academic center for students. The northern, residential portion of the main campus is located in the Powelton Village section of West Philadelphia. The two prominent performing stages at Drexel University are the Mandell Theater and the Main Auditorium. The Main Auditorium dates back to the founding of Drexel and construction of its main hall. It features over 1000 seats, and a pipe organ installed in 1928. The organ was purchased by Saturday Evening Post publisher Cyrus H. K. Curtis after he had donated a similar organ, the Curtis Organ, to nearby University of Pennsylvania and it was suggested that he do the same for Drexel. The 424-seat Mandell Theater was built in 1973 and features a more performance-oriented stage, including a full fly system, modern stage lighting facilities, stadium seating, and accommodations for wheelchairs. It is used for the semiannual spring musical, as well as various plays and many events.
The Queen Lane Campus was purchased by Drexel University as part of its acquisition of MCP Hahnemann University. It is located in the East Falls neighborhood of northwest Philadelphia and is primarily utilized by first- and second-year medical students, and researchers. A free shuttle is available, connecting the Queen Lane Campus to the Center City Hahnemann and University City Main campuses.
The Center City Campus is in the middle of Philadelphia, straddling the Vine Street Expressway between Broad and 15th Streets. Shuttle service is offered between the Center City Campus and both the University City and Queen Lane campuses of the university.
In 2011, The Academy of Natural Sciences entered into an agreement to become a subsidiary of Drexel University. Founded in 1812, the Academy of Natural Sciences is America's oldest natural history museum and is a world leader in biodiversity and environmental research.
On January 5, 2009, Drexel University opened the Center for Graduate Studies in Sacramento, California. Eventually renamed Drexel University Sacramento upon the addition of an undergraduate program in business administration, the campus also offered an Ed.D. program in Educational Leadership and Management and master's degree programs in Business Administration, Finance, Higher Education, Human Resource Development, Public Health, and Interdepartmental Medical Science. On March 5, 2015, Drexel University announced the closure of the Sacramento campus, with an 18-month "phase out" period designed to allow current students to complete their degrees.
The Graduate Student Association "advocates the interests and addresses concerns of graduate students at Drexel; strives to enhance graduate student life at the University in all aspects, from academic to campus security; and provides a formal means of communication between graduate students and the University community".
Drexel has an approximate Jewish population of 5% and has both a Chabad House and a Hillel. Both provide services to Jewish and non-Jewish students at Drexel. Due to an increase in the number of Orthodox Jewish students the Hillel has hot kosher food Monday through Thursday . There is also an eruv which is jointly managed by Jewish students from Drexel and the University of Pennsylvania.
DUTV is Drexel's Philadelphia cable television station. The student operated station is part of the Paul F. Harron Studios at Drexel University. The purpose of DUTV is to provide "the people of Philadelphia with quality educational television, and providing Drexel students the opportunity to gain experience in television management and production". The Programing includes an eclectic variety of shows from a bi-monthly news show, DNews, to old films, talk shows dealing with important current issues and music appreciation shows. Over 75 percent of DUTV's programming is student produced.
The Triangle has been the university's newspaper since 1926 and currently publishes on a biweekly basis every Friday of the academic term. The Triangle has won several Mark of Excellence Awards which honor the best in Student Journalism from the Society of Professional Journalists. First place in Editorial Writing (2000), General Column Writing (2000), Second place in Editorial Writing (2001), and third place in Sports Column Writing (2001). In 2004, it won two National Pacemaker Awards for excellence in college newspapers. In December 2019 The Triangle announced the creation of their podcasting division, "Tri-Pod,", which debuted on January 10, 2020. Tri-Pod had two podcasts, "Last Call". and "Mark and Jair Explain Sports".
The school yearbook was first published in 1911 and named the Lexerd in 1913. Prior to the publishing of a campus-wide yearbook in 1911 The Hanseatic and The Eccentric were both published in 1896 as class books.
Drexel requires all non-commuting first- and second-year students to live in one of its ten residence halls or in "university approved housing".
Second-year students have the option of living in a residence hall designated for upperclassmen, or "university approved housing". The residence halls for upperclassmen are North and Caneris Halls. North Hall operates under the For Students By Students Residential Experience Engagement Model, developed by the Residential Living Office. There are many apartments that are university approved that second-year students can choose to live in. Three of the largest apartment buildings that fit this description are Chestnut Square, University Crossings, and The Summit, all owned by American Campus Communities. Many other students live in smaller apartment buildings or individual townhouse-style apartments in Powelton Village. A second-year student can choose one of the already listed university approved housing options or petition the university to add a new property to the approved list.
Drexel University recognizes over 250 student organizations in the following categories:
Approximately 12 percent of Drexel's undergraduate population are members of a social Greek-letter organization. There are currently fourteen Interfraternity Council (IFC) chapters, seven Panhellenic Council (PHC) chapters and thirteen Multi-cultural Greek Council (MGC) chapters.
Drexel's school mascot is a dragon known as "Mario the Magnificent", named in honor of alumnus and Board of Trustees member Mario V. Mascioli. The Dragon has been the mascot of the school since around the mid-1920s; the first written reference to the Dragons occurred in 1928, when the football team was called "The Dragons in The Triangle". Before becoming known as the Dragons, the athletic teams had been known by such names as the Blue & Gold, the Engineers, and the Drexelites. The school's sports teams, now known as the Drexel Dragons, participate in the NCAA's Division I as a member of the Coastal Athletic Association. They do not currently field a varsity football team.
In addition to its NCAA Division I teams, Drexel University is home to 33 active club teams including men's ice hockey, lacrosse, water polo, squash, triathlon, and cycling. Other club teams include soccer, baseball, rugby, field hockey, and roller hockey. The club teams operate under the direction of the Club Sports Council and the Recreational Sports Office.
Since its founding the university has graduated over 100,000 alumni. Certificate-earning alumni such as artist Violet Oakley and illustrator Frank Schoonover reflect the early emphasis on art as part of the university's curriculum. With World War II, the university's technical programs swelled, and as a result Drexel graduated alumni such as Paul Baran, one of the founding fathers of the Internet and one of the inventors of the packet switching network, and Norman Joseph Woodland, the inventor of barcode technology. In addition to its emphasis on technology Drexel has graduated several notable athletes such as National Basketball Association (NBA) basketball players Michael Anderson, Damion Lee, and Malik Rose, and several notable business people such as Raj Gupta, former president and Chief executive officer (CEO) of Rohm and Haas, and Kenneth C. Dahlberg, former CEO of Science Applications International Corporation (SAIC). Alassane Dramane Ouattara President of the Republic of Ivory Coast. In 2018, Tirthak Saha -a 2016 graduate of the ECE school - was named to the Forbes 30 Under 30 list for achievements in the Energy field.
In 1991, the university's centennial anniversary, Drexel created an association called the Drexel 100, for alumni who have demonstrated excellence work, philanthropy, or public service. After the creation of the association 100 alumni were inducted in 1992 and since then the induction process has been on a biennial basis. In 2006 164 total alumni had been inducted into the association.
Drexel University created the annual $100,000 Anthony J. Drexel Exceptional Achievement Award to recognize a faculty member from a U.S. institution whose work transforms both research and the society it serves. The first recipient was bioengineer James J. Collins of Boston University (now at MIT) and the Howard Hughes Medical Institute.
In 2004, in conjunction with BAYADA Home Health Care, Drexel University's College of Nursing and Health Professions created the BAYADA Award for Technological Innovation in Nursing Education and Practice. The award honors nursing educators and practicing nurses whose innovation leads to improved patient care or improved nursing education. | [
{
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"text": "Drexel University is a private research university with its main campus in Philadelphia, Pennsylvania. Drexel's undergraduate school was founded in 1891 by Anthony J. Drexel, a financier and philanthropist. Founded as Drexel Institute of Art, Science and Industry, it was renamed Drexel Institute of Technology in 1936, before assuming its current name in 1970.",
"title": ""
},
{
"paragraph_id": 1,
"text": "As of 2020, more than 24,000 students were enrolled in over 70 undergraduate programs and more than 100 master's, doctoral, and professional programs at the university.",
"title": ""
},
{
"paragraph_id": 2,
"text": "Drexel's cooperative education program (co-op) is a unique aspect of the school's degree programs, offering students the opportunity to gain up to 18 months of paid, full-time work experience in a field relevant to their undergraduate major or graduate degree program prior to graduation.",
"title": ""
},
{
"paragraph_id": 3,
"text": "Drexel University was founded in 1891 as the Drexel Institute of Art, Science and Industry by Anthony J. Drexel, a Philadelphia financier and philanthropist. The original mission of the institution was to provide educational opportunities in the \"practical arts and sciences\" for women and men of all backgrounds.",
"title": "History"
},
{
"paragraph_id": 4,
"text": "In 1936, the institution was renamed as the Drexel Institute of Technology; in 1970, it was renamed again as the Drexel Institute of Technology. It gained university status, and was finally named Drexel University.",
"title": "History"
},
{
"paragraph_id": 5,
"text": "Despite changes during its first century, the university has remained a privately controlled, non-sectarian, coeducational center of higher learning committed to practical education and hands-on experience in an occupational setting. The central aspect of Drexel University's focus on career preparation, in the form of its cooperative education program, was introduced in 1919. Participating students alternate periods of classroom-based study with periods of full-time, practical work experience related to one's academic major and career interests.",
"title": "History"
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{
"paragraph_id": 6,
"text": "Between 1995 and 2009, Drexel University underwent a period of significant change to its programs, enrollment, and facilities under the leadership of Dr. Constantine Papadakis, the university's president during that time. Papadakis oversaw Drexel's largest expansion in its history, with a 471 percent increase in its endowment and a 102 percent increase in student enrollment. He oversaw improved performance in collegiate rankings, the implementation of a more selective approach to admissions, and a more rigorous academic program at all levels. In 2007, Drexel was the host of the 2008 Democratic presidential candidate debate in Philadelphia, televised by MSNBC.",
"title": "History"
},
{
"paragraph_id": 7,
"text": "In 2002, Drexel University acquired and assumed management of the former MCP Hahnemann University, creating the Drexel University College of Medicine. In 2006, the university established the Thomas R. Kline School of Law, and in 2011 the School of Law achieved full accreditation by the American Bar Association.",
"title": "History"
},
{
"paragraph_id": 8,
"text": "Constantine Papadakis died of pneumonia in April 2009 while still employed as the university's president. His successor, John Anderson Fry, was previously the president of Franklin & Marshall College and executive vice president of the University of Pennsylvania.",
"title": "History"
},
{
"paragraph_id": 9,
"text": "Under Fry's leadership, Drexel has continued its expansion, including the July 2011 acquisition of The Academy of Natural Sciences.",
"title": "History"
},
{
"paragraph_id": 10,
"text": "The College of Arts and Sciences was formed in 1990 when Drexel merged the two existing College of Sciences and College of Humanities together.",
"title": "Academics"
},
{
"paragraph_id": 11,
"text": "The College of Media Arts and Design \"fosters the study, exploration and management of the arts: media, design, the performing and visual\". The college offers 18 undergraduate programs and nine graduate programs, in modern art and design fields that range from architecture, graphic design and dance to fashion design and television management. Its wide range of programs has helped the college earn full accreditation from the National Association of Schools of Art and Design, the National Architectural Accrediting Board, and the Council for Interior Design Accreditation.",
"title": "Academics"
},
{
"paragraph_id": 12,
"text": "The Bennett S. LeBow College of Business history dates to the founding in 1891 of the Drexel Institute, that later became Drexel University, and of its Business Department in 1896. Today LeBow offers thirteen undergraduate majors, eight graduate programs, and two doctoral programs; 22 percent of Drexel University's undergraduate students are enrolled in a LeBow College of Business program.",
"title": "Academics"
},
{
"paragraph_id": 13,
"text": "The LeBow College of Business has been ranked as the 38th best private business school in the nation. Its online MBA program is ranked 14th in the world by the Financial Times; the publication also ranks the undergraduate business program at LeBow as 19th in the United States. The part-time MBA program ranks 1st in academic quality in the 2015 edition of Business Insider's rankings. Undergraduate and graduate entrepreneurship programs are ranked 19th in the country by the Princeton Review. Lebow College of Business's Master of Finance program is ranked 101st in the world by the 2020 QS World University Rankings.",
"title": "Academics"
},
{
"paragraph_id": 14,
"text": "Economics programs at the LeBow College of Business are housed within the School of Economics. In addition to the undergraduate program in economics, the school is home to an M.S. in Economics program as well as a PhD program in economics. Faculty members in the School of Economics have been published in the American Economic Review, RAND Journal of Economics, and Review of Economics and Statistics. The school has been ranked among the best in the world for its extensive research into matters of international trade.",
"title": "Academics"
},
{
"paragraph_id": 15,
"text": "Drexel's College of Engineering is one of its oldest and largest academic colleges, and served as the original focus of the career-oriented school upon its founding in 1891. The College of Engineering is home to several notable alumni, including two astronauts; financier Bennett S. LeBow, for whom the university's College of Business is named; and Paul Baran, inventor of the packet-switched network. Today, Drexel University's College of Engineering, which is home to 19 percent of the undergraduate student body, is known for creating the world's first engineering degree in appropriate technology. The college is also one of only 17 U.S. universities to offer a bachelor's degree in architectural engineering, and only one of five private institutions to do so.",
"title": "Academics"
},
{
"paragraph_id": 16,
"text": "The 2009 edition of U.S. News & World Report ranks the undergraduate engineering program as the 52nd-best in the nation.",
"title": "Academics"
},
{
"paragraph_id": 17,
"text": "The engineering curriculum used by the school was originally called E4 (Enhanced Educational Experience for Engineers) which was established in 1986 and funded in part by the Engineering Directorate of the National Science Foundation.",
"title": "Academics"
},
{
"paragraph_id": 18,
"text": "In 1988, the program evolved into tDEC (the Drexel Engineering Curriculum) which is composed of two full years of rigorous core engineering courses which encompass the freshman and sophomore years of the engineering student. The College of Engineering hasn't used the tDEC curriculum since approximately 2005.",
"title": "Academics"
},
{
"paragraph_id": 19,
"text": "The College of Computing and Informatics is a recent addition to Drexel University, though its programs have been offered to students for many years. The college was formed by the consolidation of the former College of Information Science & Technology (often called the \"iSchool\"), the Department of Computer Science, and the Computing and Security Technology program. Undergraduate and graduate programs in computer science, software engineering, data science, information systems, and computer security are offered by the college.",
"title": "Academics"
},
{
"paragraph_id": 20,
"text": "The Drexel University College of Medicine was added to the colleges and schools of the university in 2002, having been formed upon the acquisition of MCP Hahnemann University. In addition to its M.D. program, the College of Medicine offers more than 40 graduate programs in its Graduate School of Biomedical Sciences and Professional Studies.",
"title": "Academics"
},
{
"paragraph_id": 21,
"text": "The Graduate School of Biomedical Sciences and Professional studies offers both Master of Science and Doctor of Philosophy degree programs in fields like biochemistry, biotechnology, clinical research, and forensic science. The school also serves as the center for biomedical research at Drexel University.",
"title": "Academics"
},
{
"paragraph_id": 22,
"text": "Founded in 1961 as the United States' first Biomedical Engineering and Science Institute, the School of Biomedical Engineering, Science and Health Systems focuses on the emerging field of biomedical science at the undergraduate, graduate, and doctoral levels. Primary research areas within the school include bioinformatics, biomechanics, biomaterials, neuroengineering, and cardiovascular engineering.",
"title": "Academics"
},
{
"paragraph_id": 23,
"text": "Formed in 2002 along with the College of Medicine, Drexel's College of Nursing and Health Professions offers more than 25 programs to undergraduate and graduate students in the fields of nursing, nutrition, health sciences, health services, and radiologic technology. The college's research into matters of nutrition and rehabilitation have garnered approximately $2.9 million in external research funding on an annual basis. The physician assistant program at Drexel's College of Nursing and Health Professions is ranked in the top 15 such programs in the United States; its anesthesia programs and physical therapy programs are, respectively, ranked as top-50 programs nationwide.",
"title": "Academics"
},
{
"paragraph_id": 24,
"text": "Established in 1892, the department now known as the College of Professional Studies has focused exclusively on educational programs and pursuits for nontraditional adult learners. Today, the Goodwin College of Professional Studies offers several options designed for adult learners at all stages of career and educational development. Bachelor of Science degree completion programs are offered in part-time evening or weekend formats; graduate programs and doctoral programs are offered at the graduate level, as are self-paced \"continuing education\" courses and nearly a dozen self-paced certification programs.",
"title": "Academics"
},
{
"paragraph_id": 25,
"text": "The Pennoni Honors College, named for Drexel alumnus and trustee Dr. C.R. \"Chuck\" Pennoni '63, '66, Hon. '92, and his wife Annette, recognizes and promotes excellence among Drexel students. Students admitted to the Honors College live together and take many of the same classes; the college provides these students with access to unique cultural and social activities and a unique guest speaker series. Students are also involved in the university's Honors Student Advisory Committee and have the opportunity to take part in Drexel's \"Alternative Spring Break\", an international study tour held each spring.",
"title": "Academics"
},
{
"paragraph_id": 26,
"text": "Upon its founding in 2006, the Thomas R. Kline School of Law, originally known as the Earle Mack School of Law, was the first law school founded in Philadelphia in more than three decades. The School of Law offers L.L.M. and Master of Legal Studies degrees, in addition to the flagship Juris Doctor program, and uniquely offers cooperative education as part of its curriculum across all programs. In 2015, Bloomberg Business ranked the Kline School of Law as the second most underrated law school in the United States.",
"title": "Academics"
},
{
"paragraph_id": 27,
"text": "One of the oldest schools within Drexel University, the modern School of Education dates back to the 1891 founding of the school. Originally, the Department of Education offered teacher training to women as one of its original, career-focused degree programs. Today, the School of Education offers a coeducational approach to teacher training at the elementary and secondary levels for undergraduates. Other undergraduate programs include those focused on the intersection between learning and technology, teacher certification for non-education majors, and a minor in education for students with an interest in instruction. Graduate degrees offered by the School of Education include those in administration and leadership, special education, higher education, mathematics education, international education, and educational creativity and innovation. Doctoral degrees are offered in educational leadership and learning technologies.",
"title": "Academics"
},
{
"paragraph_id": 28,
"text": "The School of Public Health states that its mission is to \"provide education, conduct research, and partner with communities and organizations to improve the health of populations\". To that end, the school offers both a B.S. and a minor in public health for undergraduate students as well as several options for students pursuing graduate and doctoral degrees in the field. At the graduate level, the Dornsife School offers both a Master of Public Health and an Executive Master of Public Health, as well as an M.S. in biostatistics and an M.S. in epidemiology. Two Doctor of Public Health degrees are also offered, as isa Doctor of Philosophy in epidemiology. The school's graduate and doctoral students are heavily invested in the research activities of the Dornsife School of Public Health, which has helped the school attract annual funding for its four research centers.",
"title": "Academics"
},
{
"paragraph_id": 29,
"text": "The Center for Hospitality and Sport Management was formed in 2013, in an effort to house and consolidate academic programs in hospitality, tourism management, the culinary arts, and sport management. Academic programs combine the unique skills required of the sports and hospitality industries with the principles and curriculum espoused by the management programs within Drexel's LeBow College of Business.",
"title": "Academics"
},
{
"paragraph_id": 30,
"text": "Focusing specifically on the skills required to successfully start and launch a business, the Charles D. Close School of Entrepreneurship is the first and only freestanding school of entrepreneurship in the United States. Undergraduate students take part in a B.A. program in entrepreneurship and innovation, while graduate students a combined Master of Science degree in biomedicine and entrepreneurship. Minors in entrepreneurship are also offered to undergraduate students.",
"title": "Academics"
},
{
"paragraph_id": 31,
"text": "Housed within the Close School is the Baiada Institute for Entrepreneurship. The institute serves as an incubator for Drexel student startups, providing resources and mentorships to students and some post-graduates who are starting their own business while enrolled in one of the Close School's degree programs or academic minors.",
"title": "Academics"
},
{
"paragraph_id": 32,
"text": "Drexel University launched its first Internet-based education program, a master's degree in Library & Information Science, in 1996. In 2001, Drexel created its wholly owned, for-profit online education subsidiary, Drexel e-Learning, Inc., better known as Drexel University Online. It was announced in October 2013 that Drexel University Online would no longer be a for-profit venture, but rather become an internal division within the university to better serve its online student population. Although headquartered in Philadelphia, Drexel announced a new Washington, D.C., location in December 2012 to serve as both an academic and outreach center, catering to the online student population.",
"title": "Academics"
},
{
"paragraph_id": 33,
"text": "Drexel University Online founded the National Distance Learning Week, in conjunction with the United States Distance Learning Association, in 2007. In September 2010, Drexel University Online received the Sloan-C award for institution-wide excellence in online education indicating that it had exceptional programs of \"demonstrably high quality\" at the regional and national levels and across disciplines. Drexel University Online won the 2008 United States Distance Learning Association's Best Practices Awards for Distance Learning Programming. In 2007, the online education subsidiary had a revenue of $40 million. In March 2013, Drexel Online had more than 7,000 unique students from all 50 states and more than 20 countries pursuing a bachelor's, master's, or certificate. As of December 2013, Drexel University Online offers more than 100 fully accredited master's degrees, bachelor's degrees and certificate programs.",
"title": "Academics"
},
{
"paragraph_id": 34,
"text": "Drexel's longstanding cooperative education, or \"co-op\" program is one of the largest and oldest in the United States. Drexel has a fully internet-based job database, where students can submit résumés and request interviews with any of the thousands of companies that offer positions. Students also have the option of obtaining a co-op via independent search. A student graduating from Drexel's 5-year degree program typically has a total of 18 months of co-op with up to three different companies. The majority of co-ops are paid, averaging $18,720 per 6-month period, however this figure changes with major. About one third of Drexel graduates are offered full-time positions by their co-op employers right after graduation.",
"title": "Academics"
},
{
"paragraph_id": 35,
"text": "Drexel is classified among \"R1: Doctoral Universities – Very High Research Activity\". The university was ranked 51st in the 2018 edition of the \"Top 100 Worldwide Universities Granted U.S. Utility Patents\" list released by the National Academy of Inventors and the Intellectual Property Owners Association.",
"title": "Academics"
},
{
"paragraph_id": 36,
"text": "In its 2024 rankings, U.S. News & World Report ranked Drexel tied for 98th among national universities in the United States, tied for 18th in the \"Most Innovative Schools\" category, 95th in \"Best Value Schools\", and tied for 273rd in \"Top Performers on Social Mobility.",
"title": "Academics"
},
{
"paragraph_id": 37,
"text": "In its 2018 rankings, Times Higher Education World University Rankings and The Wall Street Journal ranked Drexel 74th among national universities and 351st-400th among international universities.",
"title": "Academics"
},
{
"paragraph_id": 38,
"text": "In its 2018 rankings, Forbes ranked Drexel 24th among STEM universities. In 2019, it also ranked Drexel 226th among 650 national universities, liberal arts colleges and service academies, 120th among research universities, 154th among private universities, and 96th among universities in the Northeast.",
"title": "Academics"
},
{
"paragraph_id": 39,
"text": "In 2016, Bloomberg Businessweek ranked the undergraduate business program 78th in the country. In 2014, Business Insider ranked Drexel's graduate business school 19th in the country for networking.",
"title": "Academics"
},
{
"paragraph_id": 40,
"text": "Drexel University's programs are divided across three Philadelphia-area campuses: the University City Campus, the Center City Campus and the Queen Lane College of Medicine Campus.",
"title": "Campuses"
},
{
"paragraph_id": 41,
"text": "The 77-acre (31 ha) University City Main Campus of Drexel University is located just west of the Schuylkill River in the University City district of Philadelphia. It is Drexel's largest and oldest campus; the campus contains the university's administrative offices and serves as the main academic center for students. The northern, residential portion of the main campus is located in the Powelton Village section of West Philadelphia. The two prominent performing stages at Drexel University are the Mandell Theater and the Main Auditorium. The Main Auditorium dates back to the founding of Drexel and construction of its main hall. It features over 1000 seats, and a pipe organ installed in 1928. The organ was purchased by Saturday Evening Post publisher Cyrus H. K. Curtis after he had donated a similar organ, the Curtis Organ, to nearby University of Pennsylvania and it was suggested that he do the same for Drexel. The 424-seat Mandell Theater was built in 1973 and features a more performance-oriented stage, including a full fly system, modern stage lighting facilities, stadium seating, and accommodations for wheelchairs. It is used for the semiannual spring musical, as well as various plays and many events.",
"title": "Campuses"
},
{
"paragraph_id": 42,
"text": "The Queen Lane Campus was purchased by Drexel University as part of its acquisition of MCP Hahnemann University. It is located in the East Falls neighborhood of northwest Philadelphia and is primarily utilized by first- and second-year medical students, and researchers. A free shuttle is available, connecting the Queen Lane Campus to the Center City Hahnemann and University City Main campuses.",
"title": "Campuses"
},
{
"paragraph_id": 43,
"text": "The Center City Campus is in the middle of Philadelphia, straddling the Vine Street Expressway between Broad and 15th Streets. Shuttle service is offered between the Center City Campus and both the University City and Queen Lane campuses of the university.",
"title": "Campuses"
},
{
"paragraph_id": 44,
"text": "In 2011, The Academy of Natural Sciences entered into an agreement to become a subsidiary of Drexel University. Founded in 1812, the Academy of Natural Sciences is America's oldest natural history museum and is a world leader in biodiversity and environmental research.",
"title": "Campuses"
},
{
"paragraph_id": 45,
"text": "On January 5, 2009, Drexel University opened the Center for Graduate Studies in Sacramento, California. Eventually renamed Drexel University Sacramento upon the addition of an undergraduate program in business administration, the campus also offered an Ed.D. program in Educational Leadership and Management and master's degree programs in Business Administration, Finance, Higher Education, Human Resource Development, Public Health, and Interdepartmental Medical Science. On March 5, 2015, Drexel University announced the closure of the Sacramento campus, with an 18-month \"phase out\" period designed to allow current students to complete their degrees.",
"title": "Campuses"
},
{
"paragraph_id": 46,
"text": "The Graduate Student Association \"advocates the interests and addresses concerns of graduate students at Drexel; strives to enhance graduate student life at the University in all aspects, from academic to campus security; and provides a formal means of communication between graduate students and the University community\".",
"title": "Student life"
},
{
"paragraph_id": 47,
"text": "Drexel has an approximate Jewish population of 5% and has both a Chabad House and a Hillel. Both provide services to Jewish and non-Jewish students at Drexel. Due to an increase in the number of Orthodox Jewish students the Hillel has hot kosher food Monday through Thursday . There is also an eruv which is jointly managed by Jewish students from Drexel and the University of Pennsylvania.",
"title": "Student life"
},
{
"paragraph_id": 48,
"text": "DUTV is Drexel's Philadelphia cable television station. The student operated station is part of the Paul F. Harron Studios at Drexel University. The purpose of DUTV is to provide \"the people of Philadelphia with quality educational television, and providing Drexel students the opportunity to gain experience in television management and production\". The Programing includes an eclectic variety of shows from a bi-monthly news show, DNews, to old films, talk shows dealing with important current issues and music appreciation shows. Over 75 percent of DUTV's programming is student produced.",
"title": "Student life"
},
{
"paragraph_id": 49,
"text": "The Triangle has been the university's newspaper since 1926 and currently publishes on a biweekly basis every Friday of the academic term. The Triangle has won several Mark of Excellence Awards which honor the best in Student Journalism from the Society of Professional Journalists. First place in Editorial Writing (2000), General Column Writing (2000), Second place in Editorial Writing (2001), and third place in Sports Column Writing (2001). In 2004, it won two National Pacemaker Awards for excellence in college newspapers. In December 2019 The Triangle announced the creation of their podcasting division, \"Tri-Pod,\", which debuted on January 10, 2020. Tri-Pod had two podcasts, \"Last Call\". and \"Mark and Jair Explain Sports\".",
"title": "Student life"
},
{
"paragraph_id": 50,
"text": "The school yearbook was first published in 1911 and named the Lexerd in 1913. Prior to the publishing of a campus-wide yearbook in 1911 The Hanseatic and The Eccentric were both published in 1896 as class books.",
"title": "Student life"
},
{
"paragraph_id": 51,
"text": "Drexel requires all non-commuting first- and second-year students to live in one of its ten residence halls or in \"university approved housing\".",
"title": "Student life"
},
{
"paragraph_id": 52,
"text": "Second-year students have the option of living in a residence hall designated for upperclassmen, or \"university approved housing\". The residence halls for upperclassmen are North and Caneris Halls. North Hall operates under the For Students By Students Residential Experience Engagement Model, developed by the Residential Living Office. There are many apartments that are university approved that second-year students can choose to live in. Three of the largest apartment buildings that fit this description are Chestnut Square, University Crossings, and The Summit, all owned by American Campus Communities. Many other students live in smaller apartment buildings or individual townhouse-style apartments in Powelton Village. A second-year student can choose one of the already listed university approved housing options or petition the university to add a new property to the approved list.",
"title": "Student life"
},
{
"paragraph_id": 53,
"text": "Drexel University recognizes over 250 student organizations in the following categories:",
"title": "Student life"
},
{
"paragraph_id": 54,
"text": "Approximately 12 percent of Drexel's undergraduate population are members of a social Greek-letter organization. There are currently fourteen Interfraternity Council (IFC) chapters, seven Panhellenic Council (PHC) chapters and thirteen Multi-cultural Greek Council (MGC) chapters.",
"title": "Student life"
},
{
"paragraph_id": 55,
"text": "Drexel's school mascot is a dragon known as \"Mario the Magnificent\", named in honor of alumnus and Board of Trustees member Mario V. Mascioli. The Dragon has been the mascot of the school since around the mid-1920s; the first written reference to the Dragons occurred in 1928, when the football team was called \"The Dragons in The Triangle\". Before becoming known as the Dragons, the athletic teams had been known by such names as the Blue & Gold, the Engineers, and the Drexelites. The school's sports teams, now known as the Drexel Dragons, participate in the NCAA's Division I as a member of the Coastal Athletic Association. They do not currently field a varsity football team.",
"title": "Athletics"
},
{
"paragraph_id": 56,
"text": "In addition to its NCAA Division I teams, Drexel University is home to 33 active club teams including men's ice hockey, lacrosse, water polo, squash, triathlon, and cycling. Other club teams include soccer, baseball, rugby, field hockey, and roller hockey. The club teams operate under the direction of the Club Sports Council and the Recreational Sports Office.",
"title": "Athletics"
},
{
"paragraph_id": 57,
"text": "Since its founding the university has graduated over 100,000 alumni. Certificate-earning alumni such as artist Violet Oakley and illustrator Frank Schoonover reflect the early emphasis on art as part of the university's curriculum. With World War II, the university's technical programs swelled, and as a result Drexel graduated alumni such as Paul Baran, one of the founding fathers of the Internet and one of the inventors of the packet switching network, and Norman Joseph Woodland, the inventor of barcode technology. In addition to its emphasis on technology Drexel has graduated several notable athletes such as National Basketball Association (NBA) basketball players Michael Anderson, Damion Lee, and Malik Rose, and several notable business people such as Raj Gupta, former president and Chief executive officer (CEO) of Rohm and Haas, and Kenneth C. Dahlberg, former CEO of Science Applications International Corporation (SAIC). Alassane Dramane Ouattara President of the Republic of Ivory Coast. In 2018, Tirthak Saha -a 2016 graduate of the ECE school - was named to the Forbes 30 Under 30 list for achievements in the Energy field.",
"title": "Alumni"
},
{
"paragraph_id": 58,
"text": "In 1991, the university's centennial anniversary, Drexel created an association called the Drexel 100, for alumni who have demonstrated excellence work, philanthropy, or public service. After the creation of the association 100 alumni were inducted in 1992 and since then the induction process has been on a biennial basis. In 2006 164 total alumni had been inducted into the association.",
"title": "Alumni"
},
{
"paragraph_id": 59,
"text": "Drexel University created the annual $100,000 Anthony J. Drexel Exceptional Achievement Award to recognize a faculty member from a U.S. institution whose work transforms both research and the society it serves. The first recipient was bioengineer James J. Collins of Boston University (now at MIT) and the Howard Hughes Medical Institute.",
"title": "Awards"
},
{
"paragraph_id": 60,
"text": "In 2004, in conjunction with BAYADA Home Health Care, Drexel University's College of Nursing and Health Professions created the BAYADA Award for Technological Innovation in Nursing Education and Practice. The award honors nursing educators and practicing nurses whose innovation leads to improved patient care or improved nursing education.",
"title": "Awards"
}
] | Drexel University is a private research university with its main campus in Philadelphia, Pennsylvania. Drexel's undergraduate school was founded in 1891 by Anthony J. Drexel, a financier and philanthropist. Founded as Drexel Institute of Art, Science and Industry, it was renamed Drexel Institute of Technology in 1936, before assuming its current name in 1970. As of 2020, more than 24,000 students were enrolled in over 70 undergraduate programs and more than 100 master's, doctoral, and professional programs at the university. Drexel's cooperative education program (co-op) is a unique aspect of the school's degree programs, offering students the opportunity to gain up to 18 months of paid, full-time work experience in a field relevant to their undergraduate major or graduate degree program prior to graduation. | 2001-07-28T21:05:42Z | 2023-12-28T02:07:06Z | [
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8,258 | Daedalus | In Greek mythology, Daedalus (UK: /ˈdiːdələs/, US: /ˈdɛdələs/; Greek: Δαίδαλος; Latin: Daedalus; Etruscan: Taitale) was a skillful architect and craftsman, seen as a symbol of wisdom, knowledge and power. He is the father of Icarus, the uncle of Perdix, and possibly also the father of Iapyx. Among his most famous creations are the wooden cow for Pasiphaë, the Labyrinth for King Minos of Crete which imprisoned the Minotaur, and wings that he and his son Icarus used to attempt to escape Crete. It was during this escape that Icarus did not heed his father's warnings and flew too close to the sun; the wax holding his wings together melted and Icarus fell to his death.
The name Daidalos seems to be attested in Linear B, a writing system used to record Mycenaean Greek. The name appears in the form da-da-re-jo-de, possibly referring to a sanctuary.
Daedalus's parentage was supplied as a later addition, with various authors attributing different parents to him. His father is claimed to be either Eupalamus, Metion, or Palamaon. Similarly, his mother was either Alcippe, Iphinoe, Phrasmede or Merope, daughter of King Erechtheus. Daedalus had two sons: Icarus and Iapyx, along with a nephew named either Talos, Calos, or Perdix.
The Athenians made Cretan-born Daedalus Athenian-born, the grandson of the ancient king Erechtheus, claiming that Daedalus fled to Crete after killing his nephew.
Daedalus is first mentioned in roughly 1400 BC on the Knossian Linear B tablets. He is later mentioned by Homer as the creator of a dancing floor for Ariadne, similar to that which Hephaestus placed on the Shield of Achilles. It is clear that Daedalus was not an original character of Homer's. Rather, Homer was referencing mythology that his audience was already familiar with.
Daedalus is not mentioned again in literature until the fifth century BC, but he is widely praised as an inventor, artist, and architect, though classical sources disagree on which inventions exactly are attributable to him. In Pliny's Natural History (7.198) he is credited with inventing carpentry, including tools like the axe, saw, glue, and more. Supposedly, he first invented masts and sails for ships for the navy of King Minos. He is also said to have carved statues so spirited they appeared to be living and moving. Pausanias, in traveling around Greece, attributed to Daedalus numerous archaic wooden cult figures (see xoana) that impressed him. In fact, so many other statues and artworks are attributed to Daedalus by Pausanias and various other sources that likely many of them were never made by him.
Daedalus gave his name, eponymously, to many Greek craftsmen and many Greek contraptions and inventions that represented dextrous skill. A specific sort of early Greek sculptures are named Daedalic sculpture in his honor. In Boeotia there was a festival, the Daedala, in which a temporary wooden altar was fashioned and an effigy was made from an oak-tree and dressed in bridal attire. It was carried in a cart with a woman who acted as bridesmaid. The image was called daedala. Some sources claim that the daedala did not receive their name from Daedalus, but the opposite. Pausanias claims that Daedalus was not the name given to the inventor at birth, but that he was named so later after the daedala.
Daedalus was so proud of his achievements that he could not bear the idea of a rival. His sister had placed her son under his charge to be taught the mechanical arts as an apprentice. His nephew is named variously as Perdix, Talos, or Calos, although some sources say that Perdix was the name of Daedalus' sister. The nephew showed striking evidence of ingenuity. Finding the spine of a fish on the seashore, he took a piece of iron and notched it on the edge, and thus invented the saw. He put two pieces of iron together, connecting them at one end with a rivet, and sharpening the other ends, and made a pair of compasses. Daedalus was so envious of his nephew's accomplishments that he attempted to murder him by throwing him down from the Acropolis in Athens. Athena saved his nephew and turned him into a partridge. Tried and convicted for this murder attempt, Daedalus left Athens and fled to Crete.
Daedalus created the Labyrinth on Crete, in which the Minotaur was kept.
Poseidon had given a white bull to King Minos to use it as a sacrifice. Instead, the king kept the bull for himself and sacrificed another. As revenge, Poseidon, with the help of Aphrodite, made King Minos's wife, Pasiphaë, lust for the bull. Pasiphaë asked Daedalus to help her. Daedalus built a hollow, wooden cow, covered in real cow hide for Pasiphaë, so she could mate with the bull. As a result, Pasiphaë gave birth to the Minotaur, a creature with the body of a man, but the head and tail of a bull. King Minos ordered the Minotaur to be imprisoned and guarded in the Labyrinth built by Daedalus for that purpose.
In the story of the Labyrinth as told by the Hellenes, the Athenian hero Theseus is challenged to kill the Minotaur, finding his way back out with the help of Ariadne's thread. It is Daedalus himself who gives Ariadne the clue as to how to escape the labyrinth.
Ignoring Homer, later writers envisaged the Labyrinth as an edifice rather than a single dancing path to the center and out again, and gave it numerous winding passages and turns that opened into one another, seeming to have neither beginning nor end. Ovid, in his Metamorphoses, suggests that Daedalus constructed the Labyrinth so cunningly that he himself could barely escape it after he built it.
The most familiar literary telling explaining Daedalus' wings is a late one by Ovid in his Metamorphoses.
After Theseus and Ariadne eloped together, Daedalus and his son Icarus were imprisoned by King Minos in the labyrinth that he had built. He could not leave Crete by sea, as King Minos kept a strict watch on all vessels, permitting none to sail without being carefully searched. Since Minos controlled the land routes as well, Daedalus set to work to make wings for himself and his son Icarus. Using bird feathers of various sizes, thread, and beeswax, he shaped them to resemble a bird's wings. When both were prepared for flight, Daedalus warned Icarus not to fly too high, because the heat of the sun would melt the beeswax (holding his feathers together) and the wings would break, nor too low, because the sea foam would soak the feathers and make them heavy and he would fall. After Daedalus and Icarus had passed Samos, Delos, and Lebynthos, Icarus disobeyed his father and began to soar upward toward the sun. He flew too close to the sun. Without any warning, the sun melted the wax (which held the feathers together) and they fell off. Icarus kept flapping his "wings". But he realized he had no feathers left. He was only flapping his featherless arms. The feathers --one by one-- fell like snowflakes, and down, down, and down he went into the sea (where he sank to the bottom and drowned). Seeing Icarus' wings floating in the sea, Daedalus wept, cursed his art, and (after finding Icarus's dead body on an island shore) buried Icarus's body on the island shore. Then he named the island Icaria in the memory of his child. The southeast end of the Aegean Sea where Icarus fell into the water was also called "Mare Icarium" or the Icarian Sea.
In a twist of fate, a partridge, presumably the nephew Daedalus murdered, mocked Daedalus as he buried his son. The fall and death of Icarus is seemingly portrayed as punishment for Daedalus's murder of his nephew.
After burying Icarus, Daedalus traveled to Camicus in Sicily, where he stayed as a guest under the protection of King Cocalus. There Daedalus built a temple to Apollo, and hung up his wings as an offering to the god. In an invention of Virgil (Aeneid VI), Daedalus flies to Cumae and founds his temple there, rather than in Sicily.
Minos, meanwhile, searched for Daedalus by traveling from city to city asking a riddle. He presented a spiral seashell and asked for a string to be run through it. When he reached Camicus, King Cocalus, knowing Daedalus would be able to solve the riddle, accepted the shell and gave it to Daedalus. Daedalus tied the string to an ant which, lured by a drop of honey at one end, walked through the seashell stringing it all the way through. With the riddle solved, Minos realized that Daedalus was in the court of King Cocalus and insisted he be handed over. Cocalus agreed to do so, but convinced Minos to take a bath first. In the bath, Cocalus' daughters killed Minos, possibly by pouring boiling water over his body. In some versions, it is Cocalus that kills Minos in the bath. Other variants say that Daedalus himself poured the boiling water, or that he had built the pipes that could supply hot water to the bath and this was used to instead pour boiling water on him.
At least two locations are associated with the death of Daedalus. One version of the story says he retired to the Cretan colony of Telmessos, ruled by Minos's estranged brother Sarpedon, and while wandering outside the city, he was bitten by a snake and died. A town on this site, Daidala, is said to be named after him, and is mentioned in Roman sources. Another version of the story places his death on a small island in the Nile river, where he was later worshipped.
The anecdotes are literary and late. However, in the founding tales of the Greek colony of Gela, founded in the 680s BC on the southwest coast of Sicily, a tradition was preserved that the Greeks had seized cult images wrought by Daedalus from their local predecessors, the Sicani.
Daedalus and the myths associated with him are often depicted in paintings, sculptures, and more by later artists. The myth about his flight and the fall of Icarus is especially popular in depictions. A few noteworthy pieces are included below.
There are also a number of adaptations of the myth of Daedalus and Icarus in modern literature and film, including a poem by Edward Field, several books, and band or musician names. See Daedalus (disambiguation) for more modern references. | [
{
"paragraph_id": 0,
"text": "In Greek mythology, Daedalus (UK: /ˈdiːdələs/, US: /ˈdɛdələs/; Greek: Δαίδαλος; Latin: Daedalus; Etruscan: Taitale) was a skillful architect and craftsman, seen as a symbol of wisdom, knowledge and power. He is the father of Icarus, the uncle of Perdix, and possibly also the father of Iapyx. Among his most famous creations are the wooden cow for Pasiphaë, the Labyrinth for King Minos of Crete which imprisoned the Minotaur, and wings that he and his son Icarus used to attempt to escape Crete. It was during this escape that Icarus did not heed his father's warnings and flew too close to the sun; the wax holding his wings together melted and Icarus fell to his death.",
"title": ""
},
{
"paragraph_id": 1,
"text": "The name Daidalos seems to be attested in Linear B, a writing system used to record Mycenaean Greek. The name appears in the form da-da-re-jo-de, possibly referring to a sanctuary.",
"title": "Epigraphic evidence"
},
{
"paragraph_id": 2,
"text": "Daedalus's parentage was supplied as a later addition, with various authors attributing different parents to him. His father is claimed to be either Eupalamus, Metion, or Palamaon. Similarly, his mother was either Alcippe, Iphinoe, Phrasmede or Merope, daughter of King Erechtheus. Daedalus had two sons: Icarus and Iapyx, along with a nephew named either Talos, Calos, or Perdix.",
"title": "Family"
},
{
"paragraph_id": 3,
"text": "The Athenians made Cretan-born Daedalus Athenian-born, the grandson of the ancient king Erechtheus, claiming that Daedalus fled to Crete after killing his nephew.",
"title": "Family"
},
{
"paragraph_id": 4,
"text": "Daedalus is first mentioned in roughly 1400 BC on the Knossian Linear B tablets. He is later mentioned by Homer as the creator of a dancing floor for Ariadne, similar to that which Hephaestus placed on the Shield of Achilles. It is clear that Daedalus was not an original character of Homer's. Rather, Homer was referencing mythology that his audience was already familiar with.",
"title": "Inventor, architect, artist"
},
{
"paragraph_id": 5,
"text": "Daedalus is not mentioned again in literature until the fifth century BC, but he is widely praised as an inventor, artist, and architect, though classical sources disagree on which inventions exactly are attributable to him. In Pliny's Natural History (7.198) he is credited with inventing carpentry, including tools like the axe, saw, glue, and more. Supposedly, he first invented masts and sails for ships for the navy of King Minos. He is also said to have carved statues so spirited they appeared to be living and moving. Pausanias, in traveling around Greece, attributed to Daedalus numerous archaic wooden cult figures (see xoana) that impressed him. In fact, so many other statues and artworks are attributed to Daedalus by Pausanias and various other sources that likely many of them were never made by him.",
"title": "Inventor, architect, artist"
},
{
"paragraph_id": 6,
"text": "Daedalus gave his name, eponymously, to many Greek craftsmen and many Greek contraptions and inventions that represented dextrous skill. A specific sort of early Greek sculptures are named Daedalic sculpture in his honor. In Boeotia there was a festival, the Daedala, in which a temporary wooden altar was fashioned and an effigy was made from an oak-tree and dressed in bridal attire. It was carried in a cart with a woman who acted as bridesmaid. The image was called daedala. Some sources claim that the daedala did not receive their name from Daedalus, but the opposite. Pausanias claims that Daedalus was not the name given to the inventor at birth, but that he was named so later after the daedala.",
"title": "Inventor, architect, artist"
},
{
"paragraph_id": 7,
"text": "Daedalus was so proud of his achievements that he could not bear the idea of a rival. His sister had placed her son under his charge to be taught the mechanical arts as an apprentice. His nephew is named variously as Perdix, Talos, or Calos, although some sources say that Perdix was the name of Daedalus' sister. The nephew showed striking evidence of ingenuity. Finding the spine of a fish on the seashore, he took a piece of iron and notched it on the edge, and thus invented the saw. He put two pieces of iron together, connecting them at one end with a rivet, and sharpening the other ends, and made a pair of compasses. Daedalus was so envious of his nephew's accomplishments that he attempted to murder him by throwing him down from the Acropolis in Athens. Athena saved his nephew and turned him into a partridge. Tried and convicted for this murder attempt, Daedalus left Athens and fled to Crete.",
"title": "Mythology"
},
{
"paragraph_id": 8,
"text": "Daedalus created the Labyrinth on Crete, in which the Minotaur was kept.",
"title": "Mythology"
},
{
"paragraph_id": 9,
"text": "Poseidon had given a white bull to King Minos to use it as a sacrifice. Instead, the king kept the bull for himself and sacrificed another. As revenge, Poseidon, with the help of Aphrodite, made King Minos's wife, Pasiphaë, lust for the bull. Pasiphaë asked Daedalus to help her. Daedalus built a hollow, wooden cow, covered in real cow hide for Pasiphaë, so she could mate with the bull. As a result, Pasiphaë gave birth to the Minotaur, a creature with the body of a man, but the head and tail of a bull. King Minos ordered the Minotaur to be imprisoned and guarded in the Labyrinth built by Daedalus for that purpose.",
"title": "Mythology"
},
{
"paragraph_id": 10,
"text": "In the story of the Labyrinth as told by the Hellenes, the Athenian hero Theseus is challenged to kill the Minotaur, finding his way back out with the help of Ariadne's thread. It is Daedalus himself who gives Ariadne the clue as to how to escape the labyrinth.",
"title": "Mythology"
},
{
"paragraph_id": 11,
"text": "Ignoring Homer, later writers envisaged the Labyrinth as an edifice rather than a single dancing path to the center and out again, and gave it numerous winding passages and turns that opened into one another, seeming to have neither beginning nor end. Ovid, in his Metamorphoses, suggests that Daedalus constructed the Labyrinth so cunningly that he himself could barely escape it after he built it.",
"title": "Mythology"
},
{
"paragraph_id": 12,
"text": "The most familiar literary telling explaining Daedalus' wings is a late one by Ovid in his Metamorphoses.",
"title": "Mythology"
},
{
"paragraph_id": 13,
"text": "After Theseus and Ariadne eloped together, Daedalus and his son Icarus were imprisoned by King Minos in the labyrinth that he had built. He could not leave Crete by sea, as King Minos kept a strict watch on all vessels, permitting none to sail without being carefully searched. Since Minos controlled the land routes as well, Daedalus set to work to make wings for himself and his son Icarus. Using bird feathers of various sizes, thread, and beeswax, he shaped them to resemble a bird's wings. When both were prepared for flight, Daedalus warned Icarus not to fly too high, because the heat of the sun would melt the beeswax (holding his feathers together) and the wings would break, nor too low, because the sea foam would soak the feathers and make them heavy and he would fall. After Daedalus and Icarus had passed Samos, Delos, and Lebynthos, Icarus disobeyed his father and began to soar upward toward the sun. He flew too close to the sun. Without any warning, the sun melted the wax (which held the feathers together) and they fell off. Icarus kept flapping his \"wings\". But he realized he had no feathers left. He was only flapping his featherless arms. The feathers --one by one-- fell like snowflakes, and down, down, and down he went into the sea (where he sank to the bottom and drowned). Seeing Icarus' wings floating in the sea, Daedalus wept, cursed his art, and (after finding Icarus's dead body on an island shore) buried Icarus's body on the island shore. Then he named the island Icaria in the memory of his child. The southeast end of the Aegean Sea where Icarus fell into the water was also called \"Mare Icarium\" or the Icarian Sea.",
"title": "Mythology"
},
{
"paragraph_id": 14,
"text": "In a twist of fate, a partridge, presumably the nephew Daedalus murdered, mocked Daedalus as he buried his son. The fall and death of Icarus is seemingly portrayed as punishment for Daedalus's murder of his nephew.",
"title": "Mythology"
},
{
"paragraph_id": 15,
"text": "After burying Icarus, Daedalus traveled to Camicus in Sicily, where he stayed as a guest under the protection of King Cocalus. There Daedalus built a temple to Apollo, and hung up his wings as an offering to the god. In an invention of Virgil (Aeneid VI), Daedalus flies to Cumae and founds his temple there, rather than in Sicily.",
"title": "Mythology"
},
{
"paragraph_id": 16,
"text": "Minos, meanwhile, searched for Daedalus by traveling from city to city asking a riddle. He presented a spiral seashell and asked for a string to be run through it. When he reached Camicus, King Cocalus, knowing Daedalus would be able to solve the riddle, accepted the shell and gave it to Daedalus. Daedalus tied the string to an ant which, lured by a drop of honey at one end, walked through the seashell stringing it all the way through. With the riddle solved, Minos realized that Daedalus was in the court of King Cocalus and insisted he be handed over. Cocalus agreed to do so, but convinced Minos to take a bath first. In the bath, Cocalus' daughters killed Minos, possibly by pouring boiling water over his body. In some versions, it is Cocalus that kills Minos in the bath. Other variants say that Daedalus himself poured the boiling water, or that he had built the pipes that could supply hot water to the bath and this was used to instead pour boiling water on him.",
"title": "Mythology"
},
{
"paragraph_id": 17,
"text": "At least two locations are associated with the death of Daedalus. One version of the story says he retired to the Cretan colony of Telmessos, ruled by Minos's estranged brother Sarpedon, and while wandering outside the city, he was bitten by a snake and died. A town on this site, Daidala, is said to be named after him, and is mentioned in Roman sources. Another version of the story places his death on a small island in the Nile river, where he was later worshipped.",
"title": "Mythology"
},
{
"paragraph_id": 18,
"text": "The anecdotes are literary and late. However, in the founding tales of the Greek colony of Gela, founded in the 680s BC on the southwest coast of Sicily, a tradition was preserved that the Greeks had seized cult images wrought by Daedalus from their local predecessors, the Sicani.",
"title": "Mythology"
},
{
"paragraph_id": 19,
"text": "Daedalus and the myths associated with him are often depicted in paintings, sculptures, and more by later artists. The myth about his flight and the fall of Icarus is especially popular in depictions. A few noteworthy pieces are included below.",
"title": "Later depictions in art and literature"
},
{
"paragraph_id": 20,
"text": "There are also a number of adaptations of the myth of Daedalus and Icarus in modern literature and film, including a poem by Edward Field, several books, and band or musician names. See Daedalus (disambiguation) for more modern references.",
"title": "Later depictions in art and literature"
}
] | In Greek mythology, Daedalus was a skillful architect and craftsman, seen as a symbol of wisdom, knowledge and power. He is the father of Icarus, the uncle of Perdix, and possibly also the father of Iapyx. Among his most famous creations are the wooden cow for Pasiphaë, the Labyrinth for King Minos of Crete which imprisoned the Minotaur, and wings that he and his son Icarus used to attempt to escape Crete. It was during this escape that Icarus did not heed his father's warnings and flew too close to the sun; the wax holding his wings together melted and Icarus fell to his death. | 2002-02-25T15:43:11Z | 2023-12-27T03:03:16Z | [
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] | https://en.wikipedia.org/wiki/Daedalus |
8,259 | Deception Pass | Deception Pass (Lushootseed: sčudᶻ; Samish: Xwchsónges) is a strait separating Whidbey Island from Fidalgo Island, in the northwest part of the U.S. state of Washington. It connects Skagit Bay, part of Puget Sound, with the Strait of Juan de Fuca. A pair of bridges known collectively as Deception Pass Bridge cross Deception Pass. The bridges were added to the National Register of Historic Places in 1982.
The Deception Pass area has been home to various Coast Salish tribes for thousands of years. The first Europeans to see Deception Pass were members of the 1790 expedition of Manuel Quimper on the Princesa Real. The Spanish gave it the name Boca de Flon.
A group of sailors led by Joseph Whidbey, part of the Vancouver Expedition, found and mapped Deception Pass on June 7, 1792. George Vancouver gave it the name "Deception" because it had misled him into thinking Whidbey Island was a peninsula. The "deception" was heightened due to Whidbey's failure to find the strait at first. In May 1792, Vancouver was anchored near the southern end of Whidbey Island. He sent Joseph Whidbey to explore the waters east of Whidbey Island, now known as Saratoga Passage, using small boats. Whidbey reached the northern end of Saratoga Passage and explored eastward into Skagit Bay, which is shallow and difficult to navigate. He returned south to rejoin Vancouver without having found Deception Pass. It appeared that Skagit Bay was a dead-end and that Whidbey Island and Fidalgo Island were a long peninsula attached to the mainland. In June, the expedition sailed north along the west coast of Whidbey Island. Vancouver sent Joseph Whidbey to explore inlets leading to the east. The first inlet turned out to be a "very narrow and intricate channel, which...abounded with rocks above and beneath the surface of the water". This channel led to Skagit Bay, thus separating Whidbey Island from the mainland. Vancouver apparently felt he and Joseph Whidbey had been deceived by the tricky strait. Vancouver wrote of Whidbey's efforts: "This determined [the shore they had been exploring] to be an island, which, in consequence of Mr. Whidbey’s circumnavigation, I distinguished by the name of Whidbey’s Island: and this northern pass, leading into [Skagit Bay], Deception Passage".
In the waters of Deception Pass, just east of the present-day Deception Pass Bridge, is a small island known as Ben Ure Island. The island became infamous for its activity of human smuggling of migrant Chinese people for local labor. Ben Ure and his partner Lawrence "Pirate" Kelly were quite profitable at their human smuggling business and played hide-and-seek with the United States Customs Department for years. Ure's own operation at Deception Pass in the late 1880s consisted of Ure and his Native-American wife. Local tradition has it that his wife would camp on the nearby Strawberry Island (which was visible from the open sea) and signal him with a fire on the island's summit to alert him to whether or not it was safe to attempt to bring the human cargo he illegally transported ashore. For transport, Ure would tie the people up in burlap bags so that if customs agents approached he could toss the bagged people overboard. The tidal currents carried the entrapped drowned migrants' bodies to San Juan Island to the north and west of the pass; many ended up in Dead Man's Bay.
Between 1910 and 1914, a prison rock quarry was operated on the Fidalgo Island side of the pass. Nearby barracks housed some 40 prisoners, members of an honors program out of Walla Walla State Penitentiary and the prison population was made up of several types of prisoners, including those convicted of murder. Guards stood watch at the quarry as prisoners cut the rock into gravel and loaded it onto barges at the base of the cliff atop the pass's waters. The quarried rock was then barged to the Seattle waterfront. The camp was dismantled in 1924 and although abandoned as a quarry, the remains of the camp can still be found. The location is hazardous; over the years there have been several fatal accidents when visitors have ventured onto the steep cliffs.
Upon completion on July 31, 1935, the 976-foot (297 m) span Deception Pass Bridge connected Whidbey Island to the tiny Pass Island, and Pass Island to Fidalgo Island. Prior to the bridge, travelers used an inter-island ferry to commute between Fidalgo and Whidbey islands.
Deception Pass is a dramatic seascape where the tidal flow and whirlpools beneath the twin bridges connecting Fidalgo Island to Whidbey Island move quickly. During ebb and flood tide current speed reaches about 8 knots (9.2 mph), flowing in opposite directions between ebb and flood. This swift current can lead to standing waves, large whirlpools, and roiling eddies. This swift current phenomenon can be viewed from the twin bridges' pedestrian walkways or from the trail leading below the larger south bridge from the parking lot on the Whidbey Island side. Boats can be seen waiting on either side of the pass for the current to stop or change direction before going through. Thrill-seeking kayakers go there during large tide changes to surf the standing waves and brave the class 2 and 3 rapid conditions.
Diving Deception Pass is dangerous and only for the most competent and prepared divers. There are a few times each year that the tides are right for a drift dive from the cove, under the bridge, and back to the cove as the tide changes. These must be planned well in advance by divers who know how to read currents and are aware of the dangerous conditions. However, because of the large tidal exchange, Deception Pass hosts some of the most spectacular colors and life in the Pacific Northwest. The walls and bottom are covered in colorful invertebrates, lingcod, greenlings, and barnacles everywhere.
Deception Pass is surrounded by 3,854-acre (1,560 ha) Deception Pass State Park, one of the most visited Washington state parks with over two million annual visitors.
The park was officially established in 1923, when the original 1,600 acres (650 ha) of a military reserve was transferred to Washington State Parks. The park's facilities were greatly enhanced in the 1930s when the Civilian Conservation Corps (CCC) built roads, trails, and buildings in order to develop the park. The road to West Beach was created in 1950, opening up a stretch of beach to hordes of vehicles. The former fish hatchery at Bowman Bay became a part of the park in the early 1970s. The old entrance to the park was closed in 1997 when a new entrance was created at the intersection of Highway 20 and Cornet Bay road, improving access into and out of the park.
The park's recreational facilities include campgrounds, hiking trails, beaches, and tidepools. Several miles of the Pacific Northwest Trail are within the park, most notably including the section that crosses Deception Pass on the Highway 20 bridge. In addition, the Cornet Bay Retreat Center provides cabins and dining and recreation facilities. Cornet Bay offers boat launches and fishing opportunities, while Bowman Bay has an interpretive center that explains the story of the Civilian Conservation Corps throughout Washington state. Near the center is a CCC honor statue, which can be found in 30 different states in the country. Fishing is popular in Pass Lake, on the north side of the bridge. Boat rentals and guided tours of the park are also offered.
Included in the park are ten islands: Northwest Island, Deception Island, Pass Island, Strawberry, Ben Ure, Kiket, Skagit, Hope, and Big and Little Deadman Islands. Ben Ure Island is partially privately owned. The island is not open to the public except for a small rentable cabin available via the state park, which is only accessible by rowboat.
Jonathan Raban's 1999 travel memoir Passage to Juneau describes the history of the pass and Raban's passage through it in a 30 ft yacht. The 2002 horror movie The Ring was in part filmed near the pass. The bridge is fictionalized as a toll bridge named "Desolation Bridge" in season one of The Killing. Seattle shoegaze act The Sight Below filmed the 2008 video for their track "Further Away" at Deception Pass, with Deception Island's scenic imagery prominently featured. Seattle grunge band Mudhoney named a song on their 1993 EP Five Dollar Bob's Mock Cooter Stew "Deception Pass." Seattle progressive rock band Queensrÿche filmed scenes of their video "Anybody Listening" near Deception Pass and Deception Island. | [
{
"paragraph_id": 0,
"text": "Deception Pass (Lushootseed: sčudᶻ; Samish: Xwchsónges) is a strait separating Whidbey Island from Fidalgo Island, in the northwest part of the U.S. state of Washington. It connects Skagit Bay, part of Puget Sound, with the Strait of Juan de Fuca. A pair of bridges known collectively as Deception Pass Bridge cross Deception Pass. The bridges were added to the National Register of Historic Places in 1982.",
"title": ""
},
{
"paragraph_id": 1,
"text": "The Deception Pass area has been home to various Coast Salish tribes for thousands of years. The first Europeans to see Deception Pass were members of the 1790 expedition of Manuel Quimper on the Princesa Real. The Spanish gave it the name Boca de Flon.",
"title": "History"
},
{
"paragraph_id": 2,
"text": "A group of sailors led by Joseph Whidbey, part of the Vancouver Expedition, found and mapped Deception Pass on June 7, 1792. George Vancouver gave it the name \"Deception\" because it had misled him into thinking Whidbey Island was a peninsula. The \"deception\" was heightened due to Whidbey's failure to find the strait at first. In May 1792, Vancouver was anchored near the southern end of Whidbey Island. He sent Joseph Whidbey to explore the waters east of Whidbey Island, now known as Saratoga Passage, using small boats. Whidbey reached the northern end of Saratoga Passage and explored eastward into Skagit Bay, which is shallow and difficult to navigate. He returned south to rejoin Vancouver without having found Deception Pass. It appeared that Skagit Bay was a dead-end and that Whidbey Island and Fidalgo Island were a long peninsula attached to the mainland. In June, the expedition sailed north along the west coast of Whidbey Island. Vancouver sent Joseph Whidbey to explore inlets leading to the east. The first inlet turned out to be a \"very narrow and intricate channel, which...abounded with rocks above and beneath the surface of the water\". This channel led to Skagit Bay, thus separating Whidbey Island from the mainland. Vancouver apparently felt he and Joseph Whidbey had been deceived by the tricky strait. Vancouver wrote of Whidbey's efforts: \"This determined [the shore they had been exploring] to be an island, which, in consequence of Mr. Whidbey’s circumnavigation, I distinguished by the name of Whidbey’s Island: and this northern pass, leading into [Skagit Bay], Deception Passage\".",
"title": "History"
},
{
"paragraph_id": 3,
"text": "In the waters of Deception Pass, just east of the present-day Deception Pass Bridge, is a small island known as Ben Ure Island. The island became infamous for its activity of human smuggling of migrant Chinese people for local labor. Ben Ure and his partner Lawrence \"Pirate\" Kelly were quite profitable at their human smuggling business and played hide-and-seek with the United States Customs Department for years. Ure's own operation at Deception Pass in the late 1880s consisted of Ure and his Native-American wife. Local tradition has it that his wife would camp on the nearby Strawberry Island (which was visible from the open sea) and signal him with a fire on the island's summit to alert him to whether or not it was safe to attempt to bring the human cargo he illegally transported ashore. For transport, Ure would tie the people up in burlap bags so that if customs agents approached he could toss the bagged people overboard. The tidal currents carried the entrapped drowned migrants' bodies to San Juan Island to the north and west of the pass; many ended up in Dead Man's Bay.",
"title": "History"
},
{
"paragraph_id": 4,
"text": "Between 1910 and 1914, a prison rock quarry was operated on the Fidalgo Island side of the pass. Nearby barracks housed some 40 prisoners, members of an honors program out of Walla Walla State Penitentiary and the prison population was made up of several types of prisoners, including those convicted of murder. Guards stood watch at the quarry as prisoners cut the rock into gravel and loaded it onto barges at the base of the cliff atop the pass's waters. The quarried rock was then barged to the Seattle waterfront. The camp was dismantled in 1924 and although abandoned as a quarry, the remains of the camp can still be found. The location is hazardous; over the years there have been several fatal accidents when visitors have ventured onto the steep cliffs.",
"title": "History"
},
{
"paragraph_id": 5,
"text": "Upon completion on July 31, 1935, the 976-foot (297 m) span Deception Pass Bridge connected Whidbey Island to the tiny Pass Island, and Pass Island to Fidalgo Island. Prior to the bridge, travelers used an inter-island ferry to commute between Fidalgo and Whidbey islands.",
"title": "History"
},
{
"paragraph_id": 6,
"text": "Deception Pass is a dramatic seascape where the tidal flow and whirlpools beneath the twin bridges connecting Fidalgo Island to Whidbey Island move quickly. During ebb and flood tide current speed reaches about 8 knots (9.2 mph), flowing in opposite directions between ebb and flood. This swift current can lead to standing waves, large whirlpools, and roiling eddies. This swift current phenomenon can be viewed from the twin bridges' pedestrian walkways or from the trail leading below the larger south bridge from the parking lot on the Whidbey Island side. Boats can be seen waiting on either side of the pass for the current to stop or change direction before going through. Thrill-seeking kayakers go there during large tide changes to surf the standing waves and brave the class 2 and 3 rapid conditions.",
"title": "Currents"
},
{
"paragraph_id": 7,
"text": "Diving Deception Pass is dangerous and only for the most competent and prepared divers. There are a few times each year that the tides are right for a drift dive from the cove, under the bridge, and back to the cove as the tide changes. These must be planned well in advance by divers who know how to read currents and are aware of the dangerous conditions. However, because of the large tidal exchange, Deception Pass hosts some of the most spectacular colors and life in the Pacific Northwest. The walls and bottom are covered in colorful invertebrates, lingcod, greenlings, and barnacles everywhere.",
"title": "Scuba diving"
},
{
"paragraph_id": 8,
"text": "Deception Pass is surrounded by 3,854-acre (1,560 ha) Deception Pass State Park, one of the most visited Washington state parks with over two million annual visitors.",
"title": "State park"
},
{
"paragraph_id": 9,
"text": "The park was officially established in 1923, when the original 1,600 acres (650 ha) of a military reserve was transferred to Washington State Parks. The park's facilities were greatly enhanced in the 1930s when the Civilian Conservation Corps (CCC) built roads, trails, and buildings in order to develop the park. The road to West Beach was created in 1950, opening up a stretch of beach to hordes of vehicles. The former fish hatchery at Bowman Bay became a part of the park in the early 1970s. The old entrance to the park was closed in 1997 when a new entrance was created at the intersection of Highway 20 and Cornet Bay road, improving access into and out of the park.",
"title": "State park"
},
{
"paragraph_id": 10,
"text": "The park's recreational facilities include campgrounds, hiking trails, beaches, and tidepools. Several miles of the Pacific Northwest Trail are within the park, most notably including the section that crosses Deception Pass on the Highway 20 bridge. In addition, the Cornet Bay Retreat Center provides cabins and dining and recreation facilities. Cornet Bay offers boat launches and fishing opportunities, while Bowman Bay has an interpretive center that explains the story of the Civilian Conservation Corps throughout Washington state. Near the center is a CCC honor statue, which can be found in 30 different states in the country. Fishing is popular in Pass Lake, on the north side of the bridge. Boat rentals and guided tours of the park are also offered.",
"title": "State park"
},
{
"paragraph_id": 11,
"text": "Included in the park are ten islands: Northwest Island, Deception Island, Pass Island, Strawberry, Ben Ure, Kiket, Skagit, Hope, and Big and Little Deadman Islands. Ben Ure Island is partially privately owned. The island is not open to the public except for a small rentable cabin available via the state park, which is only accessible by rowboat.",
"title": "State park"
},
{
"paragraph_id": 12,
"text": "Jonathan Raban's 1999 travel memoir Passage to Juneau describes the history of the pass and Raban's passage through it in a 30 ft yacht. The 2002 horror movie The Ring was in part filmed near the pass. The bridge is fictionalized as a toll bridge named \"Desolation Bridge\" in season one of The Killing. Seattle shoegaze act The Sight Below filmed the 2008 video for their track \"Further Away\" at Deception Pass, with Deception Island's scenic imagery prominently featured. Seattle grunge band Mudhoney named a song on their 1993 EP Five Dollar Bob's Mock Cooter Stew \"Deception Pass.\" Seattle progressive rock band Queensrÿche filmed scenes of their video \"Anybody Listening\" near Deception Pass and Deception Island.",
"title": "In popular culture"
}
] | Deception Pass is a strait separating Whidbey Island from Fidalgo Island, in the northwest part of the U.S. state of Washington. It connects Skagit Bay, part of Puget Sound, with the Strait of Juan de Fuca. A pair of bridges known collectively as Deception Pass Bridge cross Deception Pass. The bridges were added to the National Register of Historic Places in 1982. | 2002-02-25T15:51:15Z | 2023-12-07T19:19:07Z | [
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] | https://en.wikipedia.org/wiki/Deception_Pass |
8,262 | Dominoes | Dominoes is a family of tile-based games played with gaming pieces. Each domino is a rectangular tile, usually with a line dividing its face into two square ends. Each end is marked with a number of spots (also called pips or dots) or is blank. The backs of the tiles in a set are indistinguishable, either blank or having some common design. The gaming pieces make up a domino set, sometimes called a deck or pack. The traditional European domino set consists of 28 tiles, also known as pieces, bones, rocks, stones, men, cards or just dominoes, featuring all combinations of spot counts between zero and six. A domino set is a generic gaming device, similar to playing cards or dice, in that a variety of games can be played with a set. Another form of entertainment using domino pieces is the practice of domino toppling.
The earliest mention of dominoes is from Song dynasty China found in the text Former Events in Wulin by Zhou Mi (1232–1298). Modern dominoes first appeared in Italy during the 18th century, but they differ from Chinese dominoes in a number of respects, and there is no confirmed link between the two. European dominoes may have developed independently, or Italian missionaries in China may have brought the game to Europe.
The name "domino" is probably derived from the resemblance to a kind of carnival costume worn during the Venetian Carnival, often consisting of a black-hooded robe and a white mask. Despite the coinage of the word "polyomino" as a generalization, there is no connection between the word "domino" and the number 2 in any language. The most commonly played domino games are Domino Whist, Matador, and Muggins (All Fives). Other popular forms include Texas 42, Chicken Foot, Concentration, Double Fives, and Mexican Train. In Britain, the most popular league and pub game is Fives and Threes.
Dominoes have sometimes been used for divination, such as bone throwing in Chinese culture and in the African diaspora.
European-style dominoes are traditionally made of bone, silver lip ocean pearl oyster shell (mother of pearl), ivory, or a dark hardwood such as ebony, with contrasting black or white pips (inlaid or painted). Some sets feature the top half thickness in MOP, ivory, or bone, with the lower half in ebony. Alternatively, domino sets have been made from many different natural materials: stone (e.g., marble, granite or soapstone); other woods (e.g., ash, oak, redwood, and cedar); metals (e.g., brass or pewter); ceramic clay, or even frosted glass or crystal. These sets have a more novel look, and the often heavier weight makes them feel more substantial; also, such materials and the resulting products are usually much more expensive than polymer materials.
Modern commercial domino sets are usually made of synthetic materials, such as ABS or polystyrene plastics, or Bakelite and other phenolic resins; many sets approximate the look and feel of ivory while others use colored or even translucent plastics to achieve a more contemporary look. Modern sets also commonly use a different color for the dots of each different end value (one-spots might have black pips while two-spots might be green, three red, etc.) to facilitate finding matching ends. Occasionally, one may find a domino set made of card stock like that for playing cards. Such sets are lightweight, compact, and inexpensive, and like cards are more susceptible to minor disturbances such as a sudden breeze. Sometimes, the tiles have a metal pin (called a spinner or pivot) in the middle.
The traditional domino set contains one unique piece for each possible combination of two ends with zero to six spots, and is known as a double-six set because the highest-value piece has six pips on each end (the "double six"). The spots from one to six are generally arranged as they are on six-sided dice, but because blank ends having no spots are used, seven faces are possible, allowing 28 unique pieces in a double-six set.
However, this is a relatively small number especially when playing with more than four people, so many domino sets are "extended" by introducing ends with greater numbers of spots, which increases the number of unique combinations of ends and thus of pieces. Each progressively larger set increases the maximum number of pips on an end by three; so the common extended sets are double-nine (55 tiles), double-12 (91 tiles), double-15 (136 tiles), and double-18 (190 tiles), which is the maximum in practice. Larger sets such as double-21 (253 tiles) could theoretically exist, but they seem to be extremely rare if not nonexistent, as that would be far more than is normally necessary for most domino games, even with eight players. As the set becomes larger, identifying the number of pips on each domino becomes more difficult, so some large domino sets use more readable Arabic numerals instead of pips.
In China, early "domino" tiles were functionally identical to playing cards. An identifiable version of Chinese dominoes developed in the 12th or 13th century.
The oldest written mention of domino tiles in China dates to the 13th century and comes from Hangzhou where pupai (gambling plaques or tiles) and dice are listed as items sold by peddlers during the reign of Emperor Xiaozong of Song (r. 1162–1189). It is not entirely clear that pupai means dominoes, but the same term is used two centuries later by the Ming author Lu Rong (1436–1494) in a context that clearly describes domino tiles. The earliest known manual on dominoes is the Manual of the Xuanhe Period which purports to be written by Qu You (1341–1427), but some scholars believe it is a later forgery.
The traditional 32-piece Chinese domino set, made to represent each possible face of two thrown dice and thus have no blank faces, differs from the 28-piece domino set found in the West during the mid 18th century, although Chinese dominoes with blank faces were known during the 17th century. Each domino originally represented one of the 21 results of throwing two six-sided dice (2d6). One half of each domino is set with the pips from one die and the other half contains the pips from the second die. Chinese sets also introduce duplicates of some throws and divide the tiles into two suits: military and civil. Chinese dominoes are also longer than typical European ones.
Modern dominoes first appeared in Italy during the 18th century, but they differ from Chinese dominoes in a number of respects, and there is no confirmed link between the two. European dominoes may have developed independently, or Italian missionaries in China may have brought the game to Europe. Having been established in Italy, the game of dominoes spread rapidly to Austria, southern Germany and France. The game became fashionable in France in the mid-18th century. The name domino does not appear before that time, being first recorded in 1771, in the Dictionnaire de Trévoux. There are two earlier recorded meanings for the French word domino, one referring to the masquerades of the period, derived from the term for the hooded garment of a priest, the other referred to crude and brightly colored woodcuts on paper formerly popular among French peasants. The way by which this word became the name of the game of domino remains unclear. The earliest game rules in Europe describe a simple block game for two or four players. Later French rules add the variant of Domino à la Pêche ("Fishing Domino"), an early draw game as well as a three-hand game with a pool.
From France, the game was introduced to England by the late 1700s, purportedly brought in by French prisoners-of-war. The early forms of the game in England were the Block Game and Draw Game. The rules for these games were reprinted, largely unchanged, for over half a century. In 1863, a new game variously described as All Fives, Fives or Cribbage Dominoes appeared for the first time in both English and American sources; this was the first scoring game and it borrowed the counting and scoring features of cribbage, but 5 domino spots instead of 15 card points became the basic scoring unit, worth 1 game point. The game was played to 31 and employed a cribbage board to keep score. In 1864, The American Hoyle describes three new variants: Muggins, Bergen and Rounce; alongside the Block Dominoes and Draw Dominoes. In Muggins, the cribbage board was dropped, 5 spots scored 5 points, and game was now 200 for two players and 150 for three or four. Despite the name, there was no 'muggins rule' as in Cribbage to challenge a player who fails to declare his scoring combinations. This omission was rectified in the 1868 edition of The Modern Pocket Hoyle, but reprints of both rule sets continued to be produced in parallel for around twenty years before the version with the muggins rule prevailed. From around 1871, however, the names of All Fives and Muggins, became conflated and many publications issued rules for 'Muggins or All Fives' or 'Muggins or Fives' without making any distinction between the two. This confusion continues to the present day with some publications equating the names and others describing All Fives as a separate game.
In 1889, dominoes was described as having spread worldwide, "but nowhere is it more popular than in the cafés of France and Belgium. From the outset, the European game was different from the Chinese one. European domino sets contain neither the military-civilian suit distinctions of Chinese dominoes nor the duplicates that went with them. Moreover, according to Michael Dummett, in the Chinese games it is only the identity of the tile that matters; there is no concept of matching. Instead, the basic set of 28 unique tiles contains seven additional pieces, six of them representing the values that result from throwing a single die with the other half of the tile left blank, and the seventh domino representing the blank-blank (0–0) combination. Subsequently 45-piece (double eight) sets appeared in Austria and, in recent times, 55-piece (double nine) and 91-piece (double twelve) sets have been produced.
All the early games are still played today alongside games that have sprung up in the last 60 years such as Five Up, Mexican Train and Chicken Foot, the last two taking advantage of the larger domino sets available.
Some modern descriptions of All Fives are quite different from the original, having lost much of their cribbage character and incorporating a single spinner, making it identical, or closely related, to Sniff. Most published rule sets for Muggins include the rule that gives the game its name, but some modern publications omit it even though the muggins rule has been described as the unique feature of this game.
Dominoes is now played internationally. It is recognized as an "ingrained cultural activity within the Caribbean" but is also popular with the Windrush generation (who have Caribbean heritage) in the UK.
In the U.S. state of Alabama, it was illegal to play dominoes on Sunday within the state until the relevant section of the Alabama Criminal Code was repealed, effective April 21, 2015.
Dominoes (also known as bones, cards, men, pieces or tiles), are normally twice as long as they are wide, which makes it easier to re-stack pieces after use. A domino usually features a line in the middle to divide it visually into two squares, called ends. The value of either side is the number of spots or pips. In the most common variant (double-six), the values range from six pips down to none or blank. The sum of the two values, i.e. the total number of pips, may be referred to as the rank or weight of a tile; a tile may be described as "heavier" than a "lighter" one that has fewer (or no) pips.
Tiles are generally named after their two values. For instance, the following are descriptions of the tile 🁄 bearing the values two and five:
A tile that has the same pips-value on each end is called a double or doublet, and is typically referred to as double-zero 🀱, double-one 🀹, and so on. Conversely, a tile bearing different values is called a single.
Every tile which features a given number is a member of the suit of that number. A single tile is a member of two suits: for example, 🀴 belongs both to the suit of threes and the suit of blanks, or 0 suit.
In some versions the doubles can be treated as an additional suit of doubles. In these versions, the 🁡 belongs both to the suit of sixes and the suit of doubles. However, the dominant approach is that each double belongs to only one suit.
The most common domino sets commercially available are double six (with 28 tiles) and double nine (with 55 tiles). Larger sets exist and are popular for games involving several players or for players looking for long domino games.
The number of tiles in a double-n set obeys the following formula:
This formula can be simplified a little bit when n {\displaystyle n} is made equal to the total number of doubles in the domino set:
( n ) ( n + 1 ) 2 {\displaystyle {\frac {(n)(n+1)}{2}}}
The total number of pips in a double-n set is found by:
n ( n + 1 ) ( n + 2 ) 2 {\displaystyle {\frac {n(n+1)(n+2)}{2}}} i.e. the number of tiles multiplied by the maximum pip-count (n)
e.g. a 6-6 set has (7 × 8) / 2 = 56/2 = 28 tiles, the average number of pips per tile is 6 (range is from 0 to 12), giving a total pip count of 6 × 28 = 168
The most popular type of play are layout games, which fall into two main categories, blocking games and scoring games.
The most basic domino variant is for two players and requires a double-six set. The 28 tiles are shuffled face down and form the stock or boneyard. Each player draws seven tiles from the stock. Once the players begin drawing tiles, they are typically placed on-edge in front of the players, so players can see their own tiles, but not the value of their opponents' tiles. Players can thus see how many tiles remain in their opponents' hands at all times.
One player begins by downing (playing the first tile) one of their tiles. This tile starts the line of play, in which values of adjacent pairs of tile ends must match. The players alternately extend the line of play with one tile at one of its two ends; if a player is unable to place a valid tile, they must continue drawing tiles from the stock until they are able to place a tile. The game ends when one player wins by playing their last tile, or when the game is blocked because neither player can play. If that occurs, whoever caused the block receives all of the remaining player points not counting their own.
Players accrue points during game play for certain configurations, moves, or emptying one's hand. Most scoring games use variations of the draw game. If a player does not call "domino" before the tile is laid on the table, and another player says domino after the tile is laid, the first player must pick up an extra domino.
In a draw game (blocking or scoring), players are additionally allowed to draw as many tiles as desired from the stock before playing a tile, and they are not allowed to pass before the stock is (nearly) empty. The score of a game is the number of pips in the losing player's hand plus the number of pips in the stock. Most rules prescribe that two tiles need to remain in the stock. The draw game is often referred to as simply "dominoes".
Adaptations of both games can accommodate more than two players, who may play individually or in teams.
The line of play is the configuration of played tiles on the table. It starts with a single tile and typically grows in two opposite directions when players add matching tiles. In practice, players often play tiles at right angles when the line of play gets too close to the edge of the table.
The rules for the line of play often differ from one variant to another. In many rules, the doubles serve as spinners, i.e., they can be played on all four sides, causing the line of play to branch. Sometimes, the first tile is required to be a double, which serves as the only spinner. In some games such as Chicken Foot, all sides of a spinner must be occupied before anybody is allowed to play elsewhere. Matador has unusual rules for matching. Bendomino uses curved tiles, so one side of the line of play (or both) may be blocked for geometrical reasons.
In Mexican Train and other train games, the game starts with a spinner from which various trains branch off. Most trains are owned by a player and in most situations players are allowed to extend only their own train.
In blocking games, scoring happens at the end of the game. After a player has emptied their hand, thereby winning the game for the team, the score consists of the total pip count of the losing team's hands. In some rules, the pip count of the remaining stock is added. If a game is blocked because no player can move, the winner is often determined by adding the pips in players' hands.
In scoring games, each individual can potentially add to the score. For example, in Bergen, players score two points whenever they cause a configuration in which both open ends have the same value and three points if additionally one open end is formed by a double. In Muggins, players score by ensuring the total pip count of the open ends is a multiple of a certain number. In variants of Muggins, the line of play may branch due to spinners. In the common U.S. variant known as Fives players score by making the open ends a multiple of five.
In British public houses and social clubs, a scoring version of "5s-and-3s" is used. The game is normally played in pairs (two against two) and is played as a series of "ends". In each "end", the objective is for players to attach a domino from their hand to one end of those already played so that the sum of the end tiles is divisible by five or three. One point is scored for each time five or three can be divided into the sum of the two tiles, i.e. four at one end and five at the other makes nine, which is divisible by three three times, resulting in three points. Double five at one end and five at the other makes 15, which is divisible by three five times (five points) and divisible by five three times (three points) for a total of eight points.
An "end" stops when one of the players is out, i.e., has played all of their tiles. In the event no player is able to empty their hand, then the player with the lowest domino left in hand is deemed to be out and scores one point. A game consists of any number of ends with points scored in the ends accumulating towards a total. The game ends when one of the pair's total score exceeds a set number of points. A running total score is often kept on a cribbage board. 5s-and-3s is played in a number of competitive leagues in the British Isles.
Apart from the usual blocking and scoring games, also domino games of a very different character are played, such as solitaire or trick-taking games. Most of these are adaptations of card games and were once popular in certain areas to circumvent religious proscriptions against playing cards. A very simple example is a Concentration variant played with a double-six set; two tiles are considered to match if their total pip count is 12.
A popular domino game in Texas is 42. The game is similar to the card game spades. It is played with four players paired into teams. Each player draws seven tiles, and the tiles are played into tricks. Each trick counts as one point, and any domino with a multiple of five dots counts toward the total of the hand. These 35 points of "five count" and seven tricks equals 42 points, hence the name.
Dominoes is played at a professional level, similar to poker. Numerous organisations and clubs of amateur domino players exist around the world. Some organizations organize international competitions. Examples include the Anglo Caribbean Dominoes League (ACDL) in the UK which includes over 40 clubs including the Brixton Immortals.
Since April 2008, the character encoding standard Unicode includes characters that represent the double-six domino tiles. While a complete domino set has only 28 tiles, the Unicode set has "reversed" versions of the 21 tiles with different numbers on each end, a "back" image, and everything duplicated as horizontal and vertical orientations, for a total of 100 glyphs. Few fonts are known to support these glyphs. | [
{
"paragraph_id": 0,
"text": "Dominoes is a family of tile-based games played with gaming pieces. Each domino is a rectangular tile, usually with a line dividing its face into two square ends. Each end is marked with a number of spots (also called pips or dots) or is blank. The backs of the tiles in a set are indistinguishable, either blank or having some common design. The gaming pieces make up a domino set, sometimes called a deck or pack. The traditional European domino set consists of 28 tiles, also known as pieces, bones, rocks, stones, men, cards or just dominoes, featuring all combinations of spot counts between zero and six. A domino set is a generic gaming device, similar to playing cards or dice, in that a variety of games can be played with a set. Another form of entertainment using domino pieces is the practice of domino toppling.",
"title": ""
},
{
"paragraph_id": 1,
"text": "The earliest mention of dominoes is from Song dynasty China found in the text Former Events in Wulin by Zhou Mi (1232–1298). Modern dominoes first appeared in Italy during the 18th century, but they differ from Chinese dominoes in a number of respects, and there is no confirmed link between the two. European dominoes may have developed independently, or Italian missionaries in China may have brought the game to Europe.",
"title": ""
},
{
"paragraph_id": 2,
"text": "The name \"domino\" is probably derived from the resemblance to a kind of carnival costume worn during the Venetian Carnival, often consisting of a black-hooded robe and a white mask. Despite the coinage of the word \"polyomino\" as a generalization, there is no connection between the word \"domino\" and the number 2 in any language. The most commonly played domino games are Domino Whist, Matador, and Muggins (All Fives). Other popular forms include Texas 42, Chicken Foot, Concentration, Double Fives, and Mexican Train. In Britain, the most popular league and pub game is Fives and Threes.",
"title": ""
},
{
"paragraph_id": 3,
"text": "Dominoes have sometimes been used for divination, such as bone throwing in Chinese culture and in the African diaspora.",
"title": ""
},
{
"paragraph_id": 4,
"text": "European-style dominoes are traditionally made of bone, silver lip ocean pearl oyster shell (mother of pearl), ivory, or a dark hardwood such as ebony, with contrasting black or white pips (inlaid or painted). Some sets feature the top half thickness in MOP, ivory, or bone, with the lower half in ebony. Alternatively, domino sets have been made from many different natural materials: stone (e.g., marble, granite or soapstone); other woods (e.g., ash, oak, redwood, and cedar); metals (e.g., brass or pewter); ceramic clay, or even frosted glass or crystal. These sets have a more novel look, and the often heavier weight makes them feel more substantial; also, such materials and the resulting products are usually much more expensive than polymer materials.",
"title": "Construction and composition of domino sets"
},
{
"paragraph_id": 5,
"text": "Modern commercial domino sets are usually made of synthetic materials, such as ABS or polystyrene plastics, or Bakelite and other phenolic resins; many sets approximate the look and feel of ivory while others use colored or even translucent plastics to achieve a more contemporary look. Modern sets also commonly use a different color for the dots of each different end value (one-spots might have black pips while two-spots might be green, three red, etc.) to facilitate finding matching ends. Occasionally, one may find a domino set made of card stock like that for playing cards. Such sets are lightweight, compact, and inexpensive, and like cards are more susceptible to minor disturbances such as a sudden breeze. Sometimes, the tiles have a metal pin (called a spinner or pivot) in the middle.",
"title": "Construction and composition of domino sets"
},
{
"paragraph_id": 6,
"text": "The traditional domino set contains one unique piece for each possible combination of two ends with zero to six spots, and is known as a double-six set because the highest-value piece has six pips on each end (the \"double six\"). The spots from one to six are generally arranged as they are on six-sided dice, but because blank ends having no spots are used, seven faces are possible, allowing 28 unique pieces in a double-six set.",
"title": "Construction and composition of domino sets"
},
{
"paragraph_id": 7,
"text": "However, this is a relatively small number especially when playing with more than four people, so many domino sets are \"extended\" by introducing ends with greater numbers of spots, which increases the number of unique combinations of ends and thus of pieces. Each progressively larger set increases the maximum number of pips on an end by three; so the common extended sets are double-nine (55 tiles), double-12 (91 tiles), double-15 (136 tiles), and double-18 (190 tiles), which is the maximum in practice. Larger sets such as double-21 (253 tiles) could theoretically exist, but they seem to be extremely rare if not nonexistent, as that would be far more than is normally necessary for most domino games, even with eight players. As the set becomes larger, identifying the number of pips on each domino becomes more difficult, so some large domino sets use more readable Arabic numerals instead of pips.",
"title": "Construction and composition of domino sets"
},
{
"paragraph_id": 8,
"text": "In China, early \"domino\" tiles were functionally identical to playing cards. An identifiable version of Chinese dominoes developed in the 12th or 13th century.",
"title": "History"
},
{
"paragraph_id": 9,
"text": "The oldest written mention of domino tiles in China dates to the 13th century and comes from Hangzhou where pupai (gambling plaques or tiles) and dice are listed as items sold by peddlers during the reign of Emperor Xiaozong of Song (r. 1162–1189). It is not entirely clear that pupai means dominoes, but the same term is used two centuries later by the Ming author Lu Rong (1436–1494) in a context that clearly describes domino tiles. The earliest known manual on dominoes is the Manual of the Xuanhe Period which purports to be written by Qu You (1341–1427), but some scholars believe it is a later forgery.",
"title": "History"
},
{
"paragraph_id": 10,
"text": "The traditional 32-piece Chinese domino set, made to represent each possible face of two thrown dice and thus have no blank faces, differs from the 28-piece domino set found in the West during the mid 18th century, although Chinese dominoes with blank faces were known during the 17th century. Each domino originally represented one of the 21 results of throwing two six-sided dice (2d6). One half of each domino is set with the pips from one die and the other half contains the pips from the second die. Chinese sets also introduce duplicates of some throws and divide the tiles into two suits: military and civil. Chinese dominoes are also longer than typical European ones.",
"title": "History"
},
{
"paragraph_id": 11,
"text": "Modern dominoes first appeared in Italy during the 18th century, but they differ from Chinese dominoes in a number of respects, and there is no confirmed link between the two. European dominoes may have developed independently, or Italian missionaries in China may have brought the game to Europe. Having been established in Italy, the game of dominoes spread rapidly to Austria, southern Germany and France. The game became fashionable in France in the mid-18th century. The name domino does not appear before that time, being first recorded in 1771, in the Dictionnaire de Trévoux. There are two earlier recorded meanings for the French word domino, one referring to the masquerades of the period, derived from the term for the hooded garment of a priest, the other referred to crude and brightly colored woodcuts on paper formerly popular among French peasants. The way by which this word became the name of the game of domino remains unclear. The earliest game rules in Europe describe a simple block game for two or four players. Later French rules add the variant of Domino à la Pêche (\"Fishing Domino\"), an early draw game as well as a three-hand game with a pool.",
"title": "History"
},
{
"paragraph_id": 12,
"text": "From France, the game was introduced to England by the late 1700s, purportedly brought in by French prisoners-of-war. The early forms of the game in England were the Block Game and Draw Game. The rules for these games were reprinted, largely unchanged, for over half a century. In 1863, a new game variously described as All Fives, Fives or Cribbage Dominoes appeared for the first time in both English and American sources; this was the first scoring game and it borrowed the counting and scoring features of cribbage, but 5 domino spots instead of 15 card points became the basic scoring unit, worth 1 game point. The game was played to 31 and employed a cribbage board to keep score. In 1864, The American Hoyle describes three new variants: Muggins, Bergen and Rounce; alongside the Block Dominoes and Draw Dominoes. In Muggins, the cribbage board was dropped, 5 spots scored 5 points, and game was now 200 for two players and 150 for three or four. Despite the name, there was no 'muggins rule' as in Cribbage to challenge a player who fails to declare his scoring combinations. This omission was rectified in the 1868 edition of The Modern Pocket Hoyle, but reprints of both rule sets continued to be produced in parallel for around twenty years before the version with the muggins rule prevailed. From around 1871, however, the names of All Fives and Muggins, became conflated and many publications issued rules for 'Muggins or All Fives' or 'Muggins or Fives' without making any distinction between the two. This confusion continues to the present day with some publications equating the names and others describing All Fives as a separate game.",
"title": "History"
},
{
"paragraph_id": 13,
"text": "In 1889, dominoes was described as having spread worldwide, \"but nowhere is it more popular than in the cafés of France and Belgium. From the outset, the European game was different from the Chinese one. European domino sets contain neither the military-civilian suit distinctions of Chinese dominoes nor the duplicates that went with them. Moreover, according to Michael Dummett, in the Chinese games it is only the identity of the tile that matters; there is no concept of matching. Instead, the basic set of 28 unique tiles contains seven additional pieces, six of them representing the values that result from throwing a single die with the other half of the tile left blank, and the seventh domino representing the blank-blank (0–0) combination. Subsequently 45-piece (double eight) sets appeared in Austria and, in recent times, 55-piece (double nine) and 91-piece (double twelve) sets have been produced.",
"title": "History"
},
{
"paragraph_id": 14,
"text": "All the early games are still played today alongside games that have sprung up in the last 60 years such as Five Up, Mexican Train and Chicken Foot, the last two taking advantage of the larger domino sets available.",
"title": "History"
},
{
"paragraph_id": 15,
"text": "Some modern descriptions of All Fives are quite different from the original, having lost much of their cribbage character and incorporating a single spinner, making it identical, or closely related, to Sniff. Most published rule sets for Muggins include the rule that gives the game its name, but some modern publications omit it even though the muggins rule has been described as the unique feature of this game.",
"title": "History"
},
{
"paragraph_id": 16,
"text": "Dominoes is now played internationally. It is recognized as an \"ingrained cultural activity within the Caribbean\" but is also popular with the Windrush generation (who have Caribbean heritage) in the UK.",
"title": "History"
},
{
"paragraph_id": 17,
"text": "In the U.S. state of Alabama, it was illegal to play dominoes on Sunday within the state until the relevant section of the Alabama Criminal Code was repealed, effective April 21, 2015.",
"title": "History"
},
{
"paragraph_id": 18,
"text": "Dominoes (also known as bones, cards, men, pieces or tiles), are normally twice as long as they are wide, which makes it easier to re-stack pieces after use. A domino usually features a line in the middle to divide it visually into two squares, called ends. The value of either side is the number of spots or pips. In the most common variant (double-six), the values range from six pips down to none or blank. The sum of the two values, i.e. the total number of pips, may be referred to as the rank or weight of a tile; a tile may be described as \"heavier\" than a \"lighter\" one that has fewer (or no) pips.",
"title": "Tiles and suits"
},
{
"paragraph_id": 19,
"text": "Tiles are generally named after their two values. For instance, the following are descriptions of the tile 🁄 bearing the values two and five:",
"title": "Tiles and suits"
},
{
"paragraph_id": 20,
"text": "A tile that has the same pips-value on each end is called a double or doublet, and is typically referred to as double-zero 🀱, double-one 🀹, and so on. Conversely, a tile bearing different values is called a single.",
"title": "Tiles and suits"
},
{
"paragraph_id": 21,
"text": "Every tile which features a given number is a member of the suit of that number. A single tile is a member of two suits: for example, 🀴 belongs both to the suit of threes and the suit of blanks, or 0 suit.",
"title": "Tiles and suits"
},
{
"paragraph_id": 22,
"text": "In some versions the doubles can be treated as an additional suit of doubles. In these versions, the 🁡 belongs both to the suit of sixes and the suit of doubles. However, the dominant approach is that each double belongs to only one suit.",
"title": "Tiles and suits"
},
{
"paragraph_id": 23,
"text": "The most common domino sets commercially available are double six (with 28 tiles) and double nine (with 55 tiles). Larger sets exist and are popular for games involving several players or for players looking for long domino games.",
"title": "Tiles and suits"
},
{
"paragraph_id": 24,
"text": "The number of tiles in a double-n set obeys the following formula:",
"title": "Tiles and suits"
},
{
"paragraph_id": 25,
"text": "This formula can be simplified a little bit when n {\\displaystyle n} is made equal to the total number of doubles in the domino set:",
"title": "Tiles and suits"
},
{
"paragraph_id": 26,
"text": "( n ) ( n + 1 ) 2 {\\displaystyle {\\frac {(n)(n+1)}{2}}}",
"title": "Tiles and suits"
},
{
"paragraph_id": 27,
"text": "The total number of pips in a double-n set is found by:",
"title": "Tiles and suits"
},
{
"paragraph_id": 28,
"text": "n ( n + 1 ) ( n + 2 ) 2 {\\displaystyle {\\frac {n(n+1)(n+2)}{2}}} i.e. the number of tiles multiplied by the maximum pip-count (n)",
"title": "Tiles and suits"
},
{
"paragraph_id": 29,
"text": "e.g. a 6-6 set has (7 × 8) / 2 = 56/2 = 28 tiles, the average number of pips per tile is 6 (range is from 0 to 12), giving a total pip count of 6 × 28 = 168",
"title": "Tiles and suits"
},
{
"paragraph_id": 30,
"text": "The most popular type of play are layout games, which fall into two main categories, blocking games and scoring games.",
"title": "Rules"
},
{
"paragraph_id": 31,
"text": "The most basic domino variant is for two players and requires a double-six set. The 28 tiles are shuffled face down and form the stock or boneyard. Each player draws seven tiles from the stock. Once the players begin drawing tiles, they are typically placed on-edge in front of the players, so players can see their own tiles, but not the value of their opponents' tiles. Players can thus see how many tiles remain in their opponents' hands at all times.",
"title": "Rules"
},
{
"paragraph_id": 32,
"text": "One player begins by downing (playing the first tile) one of their tiles. This tile starts the line of play, in which values of adjacent pairs of tile ends must match. The players alternately extend the line of play with one tile at one of its two ends; if a player is unable to place a valid tile, they must continue drawing tiles from the stock until they are able to place a tile. The game ends when one player wins by playing their last tile, or when the game is blocked because neither player can play. If that occurs, whoever caused the block receives all of the remaining player points not counting their own.",
"title": "Rules"
},
{
"paragraph_id": 33,
"text": "Players accrue points during game play for certain configurations, moves, or emptying one's hand. Most scoring games use variations of the draw game. If a player does not call \"domino\" before the tile is laid on the table, and another player says domino after the tile is laid, the first player must pick up an extra domino.",
"title": "Rules"
},
{
"paragraph_id": 34,
"text": "In a draw game (blocking or scoring), players are additionally allowed to draw as many tiles as desired from the stock before playing a tile, and they are not allowed to pass before the stock is (nearly) empty. The score of a game is the number of pips in the losing player's hand plus the number of pips in the stock. Most rules prescribe that two tiles need to remain in the stock. The draw game is often referred to as simply \"dominoes\".",
"title": "Rules"
},
{
"paragraph_id": 35,
"text": "Adaptations of both games can accommodate more than two players, who may play individually or in teams.",
"title": "Rules"
},
{
"paragraph_id": 36,
"text": "The line of play is the configuration of played tiles on the table. It starts with a single tile and typically grows in two opposite directions when players add matching tiles. In practice, players often play tiles at right angles when the line of play gets too close to the edge of the table.",
"title": "Rules"
},
{
"paragraph_id": 37,
"text": "The rules for the line of play often differ from one variant to another. In many rules, the doubles serve as spinners, i.e., they can be played on all four sides, causing the line of play to branch. Sometimes, the first tile is required to be a double, which serves as the only spinner. In some games such as Chicken Foot, all sides of a spinner must be occupied before anybody is allowed to play elsewhere. Matador has unusual rules for matching. Bendomino uses curved tiles, so one side of the line of play (or both) may be blocked for geometrical reasons.",
"title": "Rules"
},
{
"paragraph_id": 38,
"text": "In Mexican Train and other train games, the game starts with a spinner from which various trains branch off. Most trains are owned by a player and in most situations players are allowed to extend only their own train.",
"title": "Rules"
},
{
"paragraph_id": 39,
"text": "In blocking games, scoring happens at the end of the game. After a player has emptied their hand, thereby winning the game for the team, the score consists of the total pip count of the losing team's hands. In some rules, the pip count of the remaining stock is added. If a game is blocked because no player can move, the winner is often determined by adding the pips in players' hands.",
"title": "Rules"
},
{
"paragraph_id": 40,
"text": "In scoring games, each individual can potentially add to the score. For example, in Bergen, players score two points whenever they cause a configuration in which both open ends have the same value and three points if additionally one open end is formed by a double. In Muggins, players score by ensuring the total pip count of the open ends is a multiple of a certain number. In variants of Muggins, the line of play may branch due to spinners. In the common U.S. variant known as Fives players score by making the open ends a multiple of five.",
"title": "Rules"
},
{
"paragraph_id": 41,
"text": "In British public houses and social clubs, a scoring version of \"5s-and-3s\" is used. The game is normally played in pairs (two against two) and is played as a series of \"ends\". In each \"end\", the objective is for players to attach a domino from their hand to one end of those already played so that the sum of the end tiles is divisible by five or three. One point is scored for each time five or three can be divided into the sum of the two tiles, i.e. four at one end and five at the other makes nine, which is divisible by three three times, resulting in three points. Double five at one end and five at the other makes 15, which is divisible by three five times (five points) and divisible by five three times (three points) for a total of eight points.",
"title": "Rules"
},
{
"paragraph_id": 42,
"text": "An \"end\" stops when one of the players is out, i.e., has played all of their tiles. In the event no player is able to empty their hand, then the player with the lowest domino left in hand is deemed to be out and scores one point. A game consists of any number of ends with points scored in the ends accumulating towards a total. The game ends when one of the pair's total score exceeds a set number of points. A running total score is often kept on a cribbage board. 5s-and-3s is played in a number of competitive leagues in the British Isles.",
"title": "Rules"
},
{
"paragraph_id": 43,
"text": "Apart from the usual blocking and scoring games, also domino games of a very different character are played, such as solitaire or trick-taking games. Most of these are adaptations of card games and were once popular in certain areas to circumvent religious proscriptions against playing cards. A very simple example is a Concentration variant played with a double-six set; two tiles are considered to match if their total pip count is 12.",
"title": "Rules"
},
{
"paragraph_id": 44,
"text": "A popular domino game in Texas is 42. The game is similar to the card game spades. It is played with four players paired into teams. Each player draws seven tiles, and the tiles are played into tricks. Each trick counts as one point, and any domino with a multiple of five dots counts toward the total of the hand. These 35 points of \"five count\" and seven tricks equals 42 points, hence the name.",
"title": "Rules"
},
{
"paragraph_id": 45,
"text": "Dominoes is played at a professional level, similar to poker. Numerous organisations and clubs of amateur domino players exist around the world. Some organizations organize international competitions. Examples include the Anglo Caribbean Dominoes League (ACDL) in the UK which includes over 40 clubs including the Brixton Immortals.",
"title": "Competitive play"
},
{
"paragraph_id": 46,
"text": "Since April 2008, the character encoding standard Unicode includes characters that represent the double-six domino tiles. While a complete domino set has only 28 tiles, the Unicode set has \"reversed\" versions of the 21 tiles with different numbers on each end, a \"back\" image, and everything duplicated as horizontal and vertical orientations, for a total of 100 glyphs. Few fonts are known to support these glyphs.",
"title": "Dominoes in Unicode"
}
] | Dominoes is a family of tile-based games played with gaming pieces. Each domino is a rectangular tile, usually with a line dividing its face into two square ends. Each end is marked with a number of spots or is blank. The backs of the tiles in a set are indistinguishable, either blank or having some common design. The gaming pieces make up a domino set, sometimes called a deck or pack. The traditional European domino set consists of 28 tiles, also known as pieces, bones, rocks, stones, men, cards or just dominoes, featuring all combinations of spot counts between zero and six. A domino set is a generic gaming device, similar to playing cards or dice, in that a variety of games can be played with a set. Another form of entertainment using domino pieces is the practice of domino toppling. The earliest mention of dominoes is from Song dynasty China found in the text Former Events in Wulin by Zhou Mi (1232–1298). Modern dominoes first appeared in Italy during the 18th century, but they differ from Chinese dominoes in a number of respects, and there is no confirmed link between the two. European dominoes may have developed independently, or Italian missionaries in China may have brought the game to Europe. The name "domino" is probably derived from the resemblance to a kind of carnival costume worn during the Venetian Carnival, often consisting of a black-hooded robe and a white mask. Despite the coinage of the word "polyomino" as a generalization, there is no connection between the word "domino" and the number 2 in any language.
The most commonly played domino games are Domino Whist, Matador, and Muggins. Other popular forms include Texas 42, Chicken Foot, Concentration, Double Fives, and Mexican Train. In Britain, the most popular league and pub game is Fives and Threes. Dominoes have sometimes been used for divination, such as bone throwing in Chinese culture and in the African diaspora. | 2001-08-08T10:20:30Z | 2023-12-22T11:28:33Z | [
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8,263 | Dissociation constant | In chemistry, biochemistry, and pharmacology, a dissociation constant ( K D {\displaystyle K_{D}} ) is a specific type of equilibrium constant that measures the propensity of a larger object to separate (dissociate) reversibly into smaller components, as when a complex falls apart into its component molecules, or when a salt splits up into its component ions. The dissociation constant is the inverse of the association constant. In the special case of salts, the dissociation constant can also be called an ionization constant. For a general reaction:
in which a complex A x B y {\displaystyle {\ce {A}}_{x}{\ce {B}}_{y}} breaks down into x A subunits and y B subunits, the dissociation constant is defined as
where [A], [B], and [Ax By] are the equilibrium concentrations of A, B, and the complex Ax By, respectively.
One reason for the popularity of the dissociation constant in biochemistry and pharmacology is that in the frequently encountered case where x = y = 1, KD has a simple physical interpretation: when [ A ] = K D {\displaystyle [{\ce {A}}]=K_{D}} , then [ B ] = [ AB ] {\displaystyle [{\ce {B}}]=[{\ce {AB}}]} or equivalently [ AB ] [ B ] + [ AB ] = 1 2 {\displaystyle {\tfrac {[{\ce {AB}}]}{{[{\ce {B}}]}+[{\ce {AB}}]}}={\tfrac {1}{2}}} . That is, KD, which has the dimensions of concentration, equals the concentration of free A at which half of the total molecules of B are associated with A. This simple interpretation does not apply for higher values of x or y. It also presumes the absence of competing reactions, though the derivation can be extended to explicitly allow for and describe competitive binding. It is useful as a quick description of the binding of a substance, in the same way that EC50 and IC50 describe the biological activities of substances.
Experimentally, the concentration of the molecule complex [AB] is obtained indirectly from the measurement of the concentration of a free molecules, either [A] or [B]. In principle, the total amounts of molecule [A]0 and [B]0 added to the reaction are known. They separate into free and bound components according to the mass conservation principle:
To track the concentration of the complex [AB], one substitutes the concentration of the free molecules ([A] or [B]), of the respective conservation equations, by the definition of the dissociation constant,
This yields the concentration of the complex related to the concentration of either one of the free molecules
Many biological proteins and enzymes can possess more than one binding site. Usually, when a ligand L binds with a macromolecule M, it can influence binding kinetics of other ligands L binding to the macromolecule. A simplified mechanism can be formulated if the affinity of all binding sites can be considered independent of the number of ligands bound to the macromolecule. This is valid for macromolecules composed of more than one, mostly identical, subunits. It can be then assumed that each of these n subunits are identical, symmetric and that they possess only one single binding site. Then, the concentration of bound ligands [ L ] bound {\displaystyle {\ce {[L]_{bound}}}} becomes
In this case, [ L ] bound ≠ [ LM ] {\displaystyle {\ce {[L]}}_{\text{bound}}\neq {\ce {[LM]}}} , but comprises all partially saturated forms of the macromolecule:
where the saturation occurs stepwise
For the derivation of the general binding equation a saturation function r {\displaystyle r} is defined as the quotient from the portion of bound ligand to the total amount of the macromolecule:
Even if all microscopic dissociation constants are identical, they differ from the macroscopic ones and there are differences between each binding step. The general relationship between both types of dissociation constants for n binding sites is
Hence, the ratio of bound ligand to macromolecules becomes
where ( n i ) = n ! ( n − i ) ! i ! {\displaystyle {\binom {n}{i}}={\frac {n!}{(n-i)!i!}}} is the binomial coefficient. Then, the first equation is proved by applying the binomial rule
The dissociation constant is commonly used to describe the affinity between a ligand L {\displaystyle {\ce {L}}} (such as a drug) and a protein P {\displaystyle {\ce {P}}} ; i.e., how tightly a ligand binds to a particular protein. Ligand-protein affinities are influenced by non-covalent intermolecular interactions between the two molecules such as hydrogen bonding, electrostatic interactions, hydrophobic and van der Waals forces. Affinities can also be affected by high concentrations of other macromolecules, which causes macromolecular crowding.
The formation of a ligand-protein complex LP {\displaystyle {\ce {LP}}} can be described by a two-state process
the corresponding dissociation constant is defined
where [ P ] , [ L ] {\displaystyle {\ce {[P], [L]}}} and [ LP ] {\displaystyle {\ce {[LP]}}} represent molar concentrations of the protein, ligand and complex, respectively.
The dissociation constant has molar units (M) and corresponds to the ligand concentration [ L ] {\displaystyle {\ce {[L]}}} at which half of the proteins are occupied at equilibrium, i.e., the concentration of ligand at which the concentration of protein with ligand bound [ LP ] {\displaystyle {\ce {[LP]}}} equals the concentration of protein with no ligand bound [ P ] {\displaystyle {\ce {[P]}}} . The smaller the dissociation constant, the more tightly bound the ligand is, or the higher the affinity between ligand and protein. For example, a ligand with a nanomolar (nM) dissociation constant binds more tightly to a particular protein than a ligand with a micromolar (μM) dissociation constant.
Sub-picomolar dissociation constants as a result of non-covalent binding interactions between two molecules are rare. Nevertheless, there are some important exceptions. Biotin and avidin bind with a dissociation constant of roughly 10 M = 1 fM = 0.000001 nM. Ribonuclease inhibitor proteins may also bind to ribonuclease with a similar 10 M affinity. The dissociation constant for a particular ligand-protein interaction can change significantly with solution conditions (e.g., temperature, pH and salt concentration). The effect of different solution conditions is to effectively modify the strength of any intermolecular interactions holding a particular ligand-protein complex together.
Drugs can produce harmful side effects through interactions with proteins for which they were not meant to or designed to interact. Therefore, much pharmaceutical research is aimed at designing drugs that bind to only their target proteins (Negative Design) with high affinity (typically 0.1-10 nM) or at improving the affinity between a particular drug and its in-vivo protein target (Positive Design).
In the specific case of antibodies (Ab) binding to antigen (Ag), usually the term affinity constant refers to the association constant.
This chemical equilibrium is also the ratio of the on-rate (kforward or ka) and off-rate (kback or kd) constants. Two antibodies can have the same affinity, but one may have both a high on- and off-rate constant, while the other may have both a low on- and off-rate constant.
For the deprotonation of acids, K is known as Ka, the acid dissociation constant. Stronger acids, for example sulfuric or phosphoric acid, have larger dissociation constants; weaker acids, like acetic acid, have smaller dissociation constants.
(The symbol K a {\displaystyle K_{a}} , used for the acid dissociation constant, can lead to confusion with the association constant and it may be necessary to see the reaction or the equilibrium expression to know which is meant.)
Acid dissociation constants are sometimes expressed by p K a {\displaystyle pK_{a}} , which is defined as:
This p K {\displaystyle \mathrm {p} K} notation is seen in other contexts as well; it is mainly used for covalent dissociations (i.e., reactions in which chemical bonds are made or broken) since such dissociation constants can vary greatly.
A molecule can have several acid dissociation constants. In this regard, that is depending on the number of the protons they can give up, we define monoprotic, diprotic and triprotic acids. The first (e.g., acetic acid or ammonium) have only one dissociable group, the second (carbonic acid, bicarbonate, glycine) have two dissociable groups and the third (e.g., phosphoric acid) have three dissociable groups. In the case of multiple pK values they are designated by indices: pK1, pK2, pK3 and so on. For amino acids, the pK1 constant refers to its carboxyl (-COOH) group, pK2 refers to its amino (-NH2) group and the pK3 is the pK value of its side chain.
The dissociation constant of water is denoted Kw:
The concentration of water, [H2O], is omitted by convention, which means that the value of Kw differs from the value of Keq that would be computed using that concentration.
The value of Kw varies with temperature, as shown in the table below. This variation must be taken into account when making precise measurements of quantities such as pH. | [
{
"paragraph_id": 0,
"text": "In chemistry, biochemistry, and pharmacology, a dissociation constant ( K D {\\displaystyle K_{D}} ) is a specific type of equilibrium constant that measures the propensity of a larger object to separate (dissociate) reversibly into smaller components, as when a complex falls apart into its component molecules, or when a salt splits up into its component ions. The dissociation constant is the inverse of the association constant. In the special case of salts, the dissociation constant can also be called an ionization constant. For a general reaction:",
"title": ""
},
{
"paragraph_id": 1,
"text": "in which a complex A x B y {\\displaystyle {\\ce {A}}_{x}{\\ce {B}}_{y}} breaks down into x A subunits and y B subunits, the dissociation constant is defined as",
"title": ""
},
{
"paragraph_id": 2,
"text": "where [A], [B], and [Ax By] are the equilibrium concentrations of A, B, and the complex Ax By, respectively.",
"title": ""
},
{
"paragraph_id": 3,
"text": "One reason for the popularity of the dissociation constant in biochemistry and pharmacology is that in the frequently encountered case where x = y = 1, KD has a simple physical interpretation: when [ A ] = K D {\\displaystyle [{\\ce {A}}]=K_{D}} , then [ B ] = [ AB ] {\\displaystyle [{\\ce {B}}]=[{\\ce {AB}}]} or equivalently [ AB ] [ B ] + [ AB ] = 1 2 {\\displaystyle {\\tfrac {[{\\ce {AB}}]}{{[{\\ce {B}}]}+[{\\ce {AB}}]}}={\\tfrac {1}{2}}} . That is, KD, which has the dimensions of concentration, equals the concentration of free A at which half of the total molecules of B are associated with A. This simple interpretation does not apply for higher values of x or y. It also presumes the absence of competing reactions, though the derivation can be extended to explicitly allow for and describe competitive binding. It is useful as a quick description of the binding of a substance, in the same way that EC50 and IC50 describe the biological activities of substances.",
"title": ""
},
{
"paragraph_id": 4,
"text": "Experimentally, the concentration of the molecule complex [AB] is obtained indirectly from the measurement of the concentration of a free molecules, either [A] or [B]. In principle, the total amounts of molecule [A]0 and [B]0 added to the reaction are known. They separate into free and bound components according to the mass conservation principle:",
"title": "Concentration of bound molecules"
},
{
"paragraph_id": 5,
"text": "To track the concentration of the complex [AB], one substitutes the concentration of the free molecules ([A] or [B]), of the respective conservation equations, by the definition of the dissociation constant,",
"title": "Concentration of bound molecules"
},
{
"paragraph_id": 6,
"text": "This yields the concentration of the complex related to the concentration of either one of the free molecules",
"title": "Concentration of bound molecules"
},
{
"paragraph_id": 7,
"text": "Many biological proteins and enzymes can possess more than one binding site. Usually, when a ligand L binds with a macromolecule M, it can influence binding kinetics of other ligands L binding to the macromolecule. A simplified mechanism can be formulated if the affinity of all binding sites can be considered independent of the number of ligands bound to the macromolecule. This is valid for macromolecules composed of more than one, mostly identical, subunits. It can be then assumed that each of these n subunits are identical, symmetric and that they possess only one single binding site. Then, the concentration of bound ligands [ L ] bound {\\displaystyle {\\ce {[L]_{bound}}}} becomes",
"title": "Concentration of bound molecules"
},
{
"paragraph_id": 8,
"text": "In this case, [ L ] bound ≠ [ LM ] {\\displaystyle {\\ce {[L]}}_{\\text{bound}}\\neq {\\ce {[LM]}}} , but comprises all partially saturated forms of the macromolecule:",
"title": "Concentration of bound molecules"
},
{
"paragraph_id": 9,
"text": "where the saturation occurs stepwise",
"title": "Concentration of bound molecules"
},
{
"paragraph_id": 10,
"text": "For the derivation of the general binding equation a saturation function r {\\displaystyle r} is defined as the quotient from the portion of bound ligand to the total amount of the macromolecule:",
"title": "Concentration of bound molecules"
},
{
"paragraph_id": 11,
"text": "Even if all microscopic dissociation constants are identical, they differ from the macroscopic ones and there are differences between each binding step. The general relationship between both types of dissociation constants for n binding sites is",
"title": "Concentration of bound molecules"
},
{
"paragraph_id": 12,
"text": "Hence, the ratio of bound ligand to macromolecules becomes",
"title": "Concentration of bound molecules"
},
{
"paragraph_id": 13,
"text": "where ( n i ) = n ! ( n − i ) ! i ! {\\displaystyle {\\binom {n}{i}}={\\frac {n!}{(n-i)!i!}}} is the binomial coefficient. Then, the first equation is proved by applying the binomial rule",
"title": "Concentration of bound molecules"
},
{
"paragraph_id": 14,
"text": "The dissociation constant is commonly used to describe the affinity between a ligand L {\\displaystyle {\\ce {L}}} (such as a drug) and a protein P {\\displaystyle {\\ce {P}}} ; i.e., how tightly a ligand binds to a particular protein. Ligand-protein affinities are influenced by non-covalent intermolecular interactions between the two molecules such as hydrogen bonding, electrostatic interactions, hydrophobic and van der Waals forces. Affinities can also be affected by high concentrations of other macromolecules, which causes macromolecular crowding.",
"title": "Protein-ligand binding"
},
{
"paragraph_id": 15,
"text": "The formation of a ligand-protein complex LP {\\displaystyle {\\ce {LP}}} can be described by a two-state process",
"title": "Protein-ligand binding"
},
{
"paragraph_id": 16,
"text": "the corresponding dissociation constant is defined",
"title": "Protein-ligand binding"
},
{
"paragraph_id": 17,
"text": "where [ P ] , [ L ] {\\displaystyle {\\ce {[P], [L]}}} and [ LP ] {\\displaystyle {\\ce {[LP]}}} represent molar concentrations of the protein, ligand and complex, respectively.",
"title": "Protein-ligand binding"
},
{
"paragraph_id": 18,
"text": "The dissociation constant has molar units (M) and corresponds to the ligand concentration [ L ] {\\displaystyle {\\ce {[L]}}} at which half of the proteins are occupied at equilibrium, i.e., the concentration of ligand at which the concentration of protein with ligand bound [ LP ] {\\displaystyle {\\ce {[LP]}}} equals the concentration of protein with no ligand bound [ P ] {\\displaystyle {\\ce {[P]}}} . The smaller the dissociation constant, the more tightly bound the ligand is, or the higher the affinity between ligand and protein. For example, a ligand with a nanomolar (nM) dissociation constant binds more tightly to a particular protein than a ligand with a micromolar (μM) dissociation constant.",
"title": "Protein-ligand binding"
},
{
"paragraph_id": 19,
"text": "Sub-picomolar dissociation constants as a result of non-covalent binding interactions between two molecules are rare. Nevertheless, there are some important exceptions. Biotin and avidin bind with a dissociation constant of roughly 10 M = 1 fM = 0.000001 nM. Ribonuclease inhibitor proteins may also bind to ribonuclease with a similar 10 M affinity. The dissociation constant for a particular ligand-protein interaction can change significantly with solution conditions (e.g., temperature, pH and salt concentration). The effect of different solution conditions is to effectively modify the strength of any intermolecular interactions holding a particular ligand-protein complex together.",
"title": "Protein-ligand binding"
},
{
"paragraph_id": 20,
"text": "Drugs can produce harmful side effects through interactions with proteins for which they were not meant to or designed to interact. Therefore, much pharmaceutical research is aimed at designing drugs that bind to only their target proteins (Negative Design) with high affinity (typically 0.1-10 nM) or at improving the affinity between a particular drug and its in-vivo protein target (Positive Design).",
"title": "Protein-ligand binding"
},
{
"paragraph_id": 21,
"text": "In the specific case of antibodies (Ab) binding to antigen (Ag), usually the term affinity constant refers to the association constant.",
"title": "Protein-ligand binding"
},
{
"paragraph_id": 22,
"text": "This chemical equilibrium is also the ratio of the on-rate (kforward or ka) and off-rate (kback or kd) constants. Two antibodies can have the same affinity, but one may have both a high on- and off-rate constant, while the other may have both a low on- and off-rate constant.",
"title": "Protein-ligand binding"
},
{
"paragraph_id": 23,
"text": "For the deprotonation of acids, K is known as Ka, the acid dissociation constant. Stronger acids, for example sulfuric or phosphoric acid, have larger dissociation constants; weaker acids, like acetic acid, have smaller dissociation constants.",
"title": "Acid–base reactions"
},
{
"paragraph_id": 24,
"text": "(The symbol K a {\\displaystyle K_{a}} , used for the acid dissociation constant, can lead to confusion with the association constant and it may be necessary to see the reaction or the equilibrium expression to know which is meant.)",
"title": "Acid–base reactions"
},
{
"paragraph_id": 25,
"text": "Acid dissociation constants are sometimes expressed by p K a {\\displaystyle pK_{a}} , which is defined as:",
"title": "Acid–base reactions"
},
{
"paragraph_id": 26,
"text": "This p K {\\displaystyle \\mathrm {p} K} notation is seen in other contexts as well; it is mainly used for covalent dissociations (i.e., reactions in which chemical bonds are made or broken) since such dissociation constants can vary greatly.",
"title": "Acid–base reactions"
},
{
"paragraph_id": 27,
"text": "A molecule can have several acid dissociation constants. In this regard, that is depending on the number of the protons they can give up, we define monoprotic, diprotic and triprotic acids. The first (e.g., acetic acid or ammonium) have only one dissociable group, the second (carbonic acid, bicarbonate, glycine) have two dissociable groups and the third (e.g., phosphoric acid) have three dissociable groups. In the case of multiple pK values they are designated by indices: pK1, pK2, pK3 and so on. For amino acids, the pK1 constant refers to its carboxyl (-COOH) group, pK2 refers to its amino (-NH2) group and the pK3 is the pK value of its side chain.",
"title": "Acid–base reactions"
},
{
"paragraph_id": 28,
"text": "The dissociation constant of water is denoted Kw:",
"title": "Dissociation constant of water"
},
{
"paragraph_id": 29,
"text": "The concentration of water, [H2O], is omitted by convention, which means that the value of Kw differs from the value of Keq that would be computed using that concentration.",
"title": "Dissociation constant of water"
},
{
"paragraph_id": 30,
"text": "The value of Kw varies with temperature, as shown in the table below. This variation must be taken into account when making precise measurements of quantities such as pH.",
"title": "Dissociation constant of water"
}
] | In chemistry, biochemistry, and pharmacology, a dissociation constant is a specific type of equilibrium constant that measures the propensity of a larger object to separate (dissociate) reversibly into smaller components, as when a complex falls apart into its component molecules, or when a salt splits up into its component ions. The dissociation constant is the inverse of the association constant. In the special case of salts, the dissociation constant can also be called an ionization constant. For a general reaction: in which a complex A x B y breaks down into x A subunits and y B subunits, the dissociation constant is defined as where [A], [B], and [Ax By] are the equilibrium concentrations of A, B, and the complex Ax By, respectively. One reason for the popularity of the dissociation constant in biochemistry and pharmacology is that in the frequently encountered case where x = y = 1, KD has a simple physical interpretation: when [ A ] = K D , then [ B ] = [ AB ] or equivalently [ AB ] [ B ] + [ AB ] = 1 2 . That is, KD, which has the dimensions of concentration, equals the concentration of free A at which half of the total molecules of B are associated with A. This simple interpretation does not apply for higher values of x or y. It also presumes the absence of competing reactions, though the derivation can be extended to explicitly allow for and describe competitive binding. It is useful as a quick description of the binding of a substance, in the same way that EC50 and IC50 describe the biological activities of substances. | 2023-05-30T06:51:52Z | [
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|
8,267 | Dimensional analysis | In engineering and science, dimensional analysis is the analysis of the relationships between different physical quantities by identifying their base quantities (such as length, mass, time, and electric current) and units of measurement (such as metres and grams) and tracking these dimensions as calculations or comparisons are performed. The term dimensional analysis is also used to refer to conversion of units from one dimensional unit to another, which can be used to evaluate scientific formulae.
Commensurable physical quantities are of the same kind and have the same dimension, and can be directly compared to each other, even if they are expressed in differing units of measurement; e.g., metres and feet, grams and pounds, seconds and years. Incommensurable physical quantities are of different kinds and have different dimensions, and can not be directly compared to each other, no matter what units they are expressed in, e.g. metres and grams, seconds and grams, metres and seconds. For example, asking whether a gram is larger than an hour is meaningless.
Any physically meaningful equation, or inequality, must have the same dimensions on its left and right sides, a property known as dimensional homogeneity. Checking for dimensional homogeneity is a common application of dimensional analysis, serving as a plausibility check on derived equations and computations. It also serves as a guide and constraint in deriving equations that may describe a physical system in the absence of a more rigorous derivation.
The concept of physical dimension, and of dimensional analysis, was introduced by Joseph Fourier in 1822.
The Buckingham π theorem describes how every physically meaningful equation involving n variables can be equivalently rewritten as an equation of n − m dimensionless parameters, where m is the rank of the dimensional matrix. Furthermore, and most importantly, it provides a method for computing these dimensionless parameters from the given variables.
A dimensional equation can have the dimensions reduced or eliminated through nondimensionalization, which begins with dimensional analysis, and involves scaling quantities by characteristic units of a system or physical constants of nature. This may give insight into the fundamental properties of the system, as illustrated in the examples below.
The dimension of a physical quantity can be expressed as a product of the base physical dimensions such as length, mass and time, each raised to an integer (and occasionally rational) power. The dimension of a physical quantity is more fundamental than some scale or unit used to express the amount of that physical quantity. For example, mass is a dimension, while the kilogram is a particular reference quantity chosen to express a quantity of mass. The choice of unit is arbitrary, and its choice is often based on historical precedent. Natural units, being based on only universal constants, may be thought of as being "less arbitrary".
There are many possible choices of base physical dimensions. The SI standard selects the following dimensions and corresponding dimension symbols:
The symbols are by convention usually written in roman sans serif typeface. Mathematically, the dimension of the quantity Q is given by
where a, b, c, d, e, f, g are the dimensional exponents. Other physical quantities could be defined as the base quantities, as long as they form a linearly independent basis – for instance, one could replace the dimension (I) of electric current of the SI basis with a dimension (Q) of electric charge, since Q = TI.
A quantity that has only b ≠ 0 (with all other exponents zero) is known as a geometric quantity. A quantity that has only both a ≠ 0 and b ≠ 0 is known as a kinematic quantity. A quantity that has only all of a ≠ 0, b ≠ 0, and c ≠ 0 is known as a dynamic quantity. A quantity that has all exponents null is said to have dimension one.
The unit chosen to express a physical quantity and its dimension are related, but not identical concepts. The units of a physical quantity are defined by convention and related to some standard; e.g., length may have units of metres, feet, inches, miles or micrometres; but any length always has a dimension of L, no matter what units of length are chosen to express it. Two different units of the same physical quantity have conversion factors that relate them. For example, 1 in = 2.54 cm; in this case 2.54 cm/in is the conversion factor, which is itself dimensionless. Therefore, multiplying by that conversion factor does not change the dimensions of a physical quantity.
There are also physicists who have cast doubt on the very existence of incompatible fundamental dimensions of physical quantity, although this does not invalidate the usefulness of dimensional analysis.
As examples, the dimension of the physical quantity speed v is
The dimension of the physical quantity force F is
The dimension of the physical quantity pressure P is
The dimension of the physical quantity energy E is
The dimension of the physical quantity power P is
The dimension of the physical quantity electric charge Q is
The dimension of the physical quantity electric potential difference V is
The dimension of the physical quantity capacitance C is
In dimensional analysis, Rayleigh's method is a conceptual tool used in physics, chemistry, and engineering. It expresses a functional relationship of some variables in the form of an exponential equation. It was named after Lord Rayleigh.
The method involves the following steps:
As a drawback, Rayleigh's method does not provide any information regarding number of dimensionless groups to be obtained as a result of dimensional analysis.
Many parameters and measurements in the physical sciences and engineering are expressed as a concrete number—a numerical quantity and a corresponding dimensional unit. Often a quantity is expressed in terms of several other quantities; for example, speed is a combination of length and time, e.g. 60 kilometres per hour or 1.4 kilometres per second. Compound relations with "per" are expressed with division, e.g. 60 km/h. Other relations can involve multiplication (often shown with a centered dot or juxtaposition), powers (like m for square metres), or combinations thereof.
A set of base units for a system of measurement is a conventionally chosen set of units, none of which can be expressed as a combination of the others and in terms of which all the remaining units of the system can be expressed. For example, units for length and time are normally chosen as base units. Units for volume, however, can be factored into the base units of length (m), thus they are considered derived or compound units.
Sometimes the names of units obscure the fact that they are derived units. For example, a newton (N) is a unit of force, which may be expressed as the product of mass (with unit kg) and acceleration (with unit m⋅s). The newton is defined as 1 N = 1 kg⋅m⋅s.
Percentages are dimensionless quantities, since they are ratios of two quantities with the same dimensions. In other words, the % sign can be read as "hundredths", since 1% = 1/100.
Taking a derivative with respect to a quantity divides the dimension by the dimension of the variable that is differentiated with respect to. Thus:
Likewise, taking an integral adds the dimension of the variable one is integrating with respect to, but in the numerator.
In economics, one distinguishes between stocks and flows: a stock has a unit (say, widgets or dollars), while a flow is a derivative of a stock, and has a unit of the form of this unit divided by one of time (say, dollars/year).
In some contexts, dimensional quantities are expressed as dimensionless quantities or percentages by omitting some dimensions. For example, debt-to-GDP ratios are generally expressed as percentages: total debt outstanding (dimension of currency) divided by annual GDP (dimension of currency)—but one may argue that, in comparing a stock to a flow, annual GDP should have dimensions of currency/time (dollars/year, for instance) and thus debt-to-GDP should have the unit year, which indicates that debt-to-GDP is the number of years needed for a constant GDP to pay the debt, if all GDP is spent on the debt and the debt is otherwise unchanged.
The most basic rule of dimensional analysis is that of dimensional homogeneity.
However, the dimensions form an abelian group under multiplication, so:
For example, it makes no sense to ask whether 1 hour is more, the same, or less than 1 kilometre, as these have different dimensions, nor to add 1 hour to 1 kilometre. However, it makes sense to ask whether 1 mile is more, the same, or less than 1 kilometre, being the same dimension of physical quantity even though the units are different. On the other hand, if an object travels 100 km in 2 hours, one may divide these and conclude that the object's average speed was 50 km/h.
The rule implies that in a physically meaningful expression only quantities of the same dimension can be added, subtracted, or compared. For example, if mman, mrat and Lman denote, respectively, the mass of some man, the mass of a rat and the length of that man, the dimensionally homogeneous expression mman + mrat is meaningful, but the heterogeneous expression mman + Lman is meaningless. However, mman/Lman is fine. Thus, dimensional analysis may be used as a sanity check of physical equations: the two sides of any equation must be commensurable or have the same dimensions.
Even when two physical quantities have identical dimensions, it may nevertheless be meaningless to compare or add them. For example, although torque and energy share the dimension TLM, they are fundamentally different physical quantities.
To compare, add, or subtract quantities with the same dimensions but expressed in different units, the standard procedure is first to convert them all to the same unit. For example, to compare 32 metres with 35 yards, use 1 yard = 0.9144 m to convert 35 yards to 32.004 m.
A related principle is that any physical law that accurately describes the real world must be independent of the units used to measure the physical variables. For example, Newton's laws of motion must hold true whether distance is measured in miles or kilometres. This principle gives rise to the form that a conversion factor between a unit that measures the same dimension must take: multiplication by a simple constant. It also ensures equivalence; for example, if two buildings are the same height in feet, then they must be the same height in metres.
In dimensional analysis, a ratio which converts one unit of measure into another without changing the quantity is called a conversion factor. For example, kPa and bar are both units of pressure, and 100 kPa = 1 bar. The rules of algebra allow both sides of an equation to be divided by the same expression, so this is equivalent to 100 kPa / 1 bar = 1. Since any quantity can be multiplied by 1 without changing it, the expression "100 kPa / 1 bar" can be used to convert from bars to kPa by multiplying it with the quantity to be converted, including the unit. For example, 5 bar × 100 kPa / 1 bar = 500 kPa because 5 × 100 / 1 = 500, and bar/bar cancels out, so 5 bar = 500 kPa.
Dimensional analysis is most often used in physics and chemistry – and in the mathematics thereof – but finds some applications outside of those fields as well.
A simple application of dimensional analysis to mathematics is in computing the form of the volume of an n-ball (the solid ball in n dimensions), or the area of its surface, the n-sphere: being an n-dimensional figure, the volume scales as x, while the surface area, being (n − 1)-dimensional, scales as x. Thus the volume of the n-ball in terms of the radius is Cr, for some constant C. Determining the constant takes more involved mathematics, but the form can be deduced and checked by dimensional analysis alone.
In finance, economics, and accounting, dimensional analysis is most commonly referred to in terms of the distinction between stocks and flows. More generally, dimensional analysis is used in interpreting various financial ratios, economics ratios, and accounting ratios.
In fluid mechanics, dimensional analysis is performed to obtain dimensionless pi terms or groups. According to the principles of dimensional analysis, any prototype can be described by a series of these terms or groups that describe the behaviour of the system. Using suitable pi terms or groups, it is possible to develop a similar set of pi terms for a model that has the same dimensional relationships. In other words, pi terms provide a shortcut to developing a model representing a certain prototype. Common dimensionless groups in fluid mechanics include:
The origins of dimensional analysis have been disputed by historians. The first written application of dimensional analysis has been credited to François Daviet, a student of Lagrange, in a 1799 article at the Turin Academy of Science.
This led to the conclusion that meaningful laws must be homogeneous equations in their various units of measurement, a result which was eventually later formalized in the Buckingham π theorem. Simeon Poisson also treated the same problem of the parallelogram law by Daviet, in his treatise of 1811 and 1833 (vol I, p. 39). In the second edition of 1833, Poisson explicitly introduces the term dimension instead of the Daviet homogeneity.
In 1822, the important Napoleonic scientist Joseph Fourier made the first credited important contributions based on the idea that physical laws like F = ma should be independent of the units employed to measure the physical variables.
James Clerk Maxwell played a major role in establishing modern use of dimensional analysis by distinguishing mass, length, and time as fundamental units, while referring to other units as derived. Although Maxwell defined length, time and mass to be "the three fundamental units", he also noted that gravitational mass can be derived from length and time by assuming a form of Newton's law of universal gravitation in which the gravitational constant G is taken as unity, thereby defining M = TL. By assuming a form of Coulomb's law in which the Coulomb constant ke is taken as unity, Maxwell then determined that the dimensions of an electrostatic unit of charge were Q = TLM, which, after substituting his M = TL equation for mass, results in charge having the same dimensions as mass, viz. Q = TL.
Dimensional analysis is also used to derive relationships between the physical quantities that are involved in a particular phenomenon that one wishes to understand and characterize. It was used for the first time in this way in 1872 by Lord Rayleigh, who was trying to understand why the sky is blue. Rayleigh first published the technique in his 1877 book The Theory of Sound.
The original meaning of the word dimension, in Fourier's Theorie de la Chaleur, was the numerical value of the exponents of the base units. For example, acceleration was considered to have the dimension 1 with respect to the unit of length, and the dimension −2 with respect to the unit of time. This was slightly changed by Maxwell, who said the dimensions of acceleration are TL, instead of just the exponents.
What is the period of oscillation T of a mass m attached to an ideal linear spring with spring constant k suspended in gravity of strength g? That period is the solution for T of some dimensionless equation in the variables T, m, k, and g. The four quantities have the following dimensions: T [T]; m [M]; k [M/T]; and g [L/T]. From these we can form only one dimensionless product of powers of our chosen variables, G1 = Tk/m [T · M/T / M = 1], and putting G1 = C for some dimensionless constant C gives the dimensionless equation sought. The dimensionless product of powers of variables is sometimes referred to as a dimensionless group of variables; here the term "group" means "collection" rather than mathematical group. They are often called dimensionless numbers as well.
The variable g does not occur in the group. It is easy to see that it is impossible to form a dimensionless product of powers that combines g with k, m, and T, because g is the only quantity that involves the dimension L. This implies that in this problem the g is irrelevant. Dimensional analysis can sometimes yield strong statements about the irrelevance of some quantities in a problem, or the need for additional parameters. If we have chosen enough variables to properly describe the problem, then from this argument we can conclude that the period of the mass on the spring is independent of g: it is the same on the earth or the moon. The equation demonstrating the existence of a product of powers for our problem can be written in an entirely equivalent way: T = κ m k {\displaystyle T=\kappa {\sqrt {\tfrac {m}{k}}}} , for some dimensionless constant κ (equal to C {\displaystyle {\sqrt {C}}} from the original dimensionless equation).
When faced with a case where dimensional analysis rejects a variable (g, here) that one intuitively expects to belong in a physical description of the situation, another possibility is that the rejected variable is in fact relevant, but that some other relevant variable has been omitted, which might combine with the rejected variable to form a dimensionless quantity. That is, however, not the case here.
When dimensional analysis yields only one dimensionless group, as here, there are no unknown functions, and the solution is said to be "complete" – although it still may involve unknown dimensionless constants, such as κ.
Consider the case of a vibrating wire of length ℓ (L) vibrating with an amplitude A (L). The wire has a linear density ρ (M/L) and is under tension s (LM/T), and we want to know the energy E (LM/T) in the wire. Let π1 and π2 be two dimensionless products of powers of the variables chosen, given by
The linear density of the wire is not involved. The two groups found can be combined into an equivalent form as an equation
where F is some unknown function, or, equivalently as
where f is some other unknown function. Here the unknown function implies that our solution is now incomplete, but dimensional analysis has given us something that may not have been obvious: the energy is proportional to the first power of the tension. Barring further analytical analysis, we might proceed to experiments to discover the form for the unknown function f. But our experiments are simpler than in the absence of dimensional analysis. We'd perform none to verify that the energy is proportional to the tension. Or perhaps we might guess that the energy is proportional to ℓ, and so infer that E = ℓs. The power of dimensional analysis as an aid to experiment and forming hypotheses becomes evident.
The power of dimensional analysis really becomes apparent when it is applied to situations, unlike those given above, that are more complicated, the set of variables involved are not apparent, and the underlying equations hopelessly complex. Consider, for example, a small pebble sitting on the bed of a river. If the river flows fast enough, it will actually raise the pebble and cause it to flow along with the water. At what critical velocity will this occur? Sorting out the guessed variables is not so easy as before. But dimensional analysis can be a powerful aid in understanding problems like this, and is usually the very first tool to be applied to complex problems where the underlying equations and constraints are poorly understood. In such cases, the answer may depend on a dimensionless number such as the Reynolds number, which may be interpreted by dimensional analysis.
Consider the case of a thin, solid, parallel-sided rotating disc of axial thickness t (L) and radius R (L). The disc has a density ρ (M/L), rotates at an angular velocity ω (T) and this leads to a stress S (TLM) in the material. There is a theoretical linear elastic solution, given by Lame, to this problem when the disc is thin relative to its radius, the faces of the disc are free to move axially, and the plane stress constitutive relations can be assumed to be valid. As the disc becomes thicker relative to the radius then the plane stress solution breaks down. If the disc is restrained axially on its free faces then a state of plane strain will occur. However, if this is not the case then the state of stress may only be determined though consideration of three-dimensional elasticity and there is no known theoretical solution for this case. An engineer might, therefore, be interested in establishing a relationship between the five variables. Dimensional analysis for this case leads to the following (5 − 3 = 2) non-dimensional groups:
Through the use of numerical experiments using, for example, the finite element method, the nature of the relationship between the two non-dimensional groups can be obtained as shown in the figure. As this problem only involves two non-dimensional groups, the complete picture is provided in a single plot and this can be used as a design/assessment chart for rotating discs.
The dimensions that can be formed from a given collection of basic physical dimensions, such as T, L, and M, form an abelian group: The identity is written as 1; L = 1, and the inverse of L is 1/L or L. L raised to any integer power p is a member of the group, having an inverse of L or 1/L. The operation of the group is multiplication, having the usual rules for handling exponents (L × L = L). Physically, 1/L can be interpreted as reciprocal length, and 1/T as reciprocal time (see reciprocal second).
An abelian group is equivalent to a module over the integers, with the dimensional symbol TLM corresponding to the tuple (i, j, k). When physical measured quantities (be they like-dimensioned or unlike-dimensioned) are multiplied or divided by one other, their dimensional units are likewise multiplied or divided; this corresponds to addition or subtraction in the module. When measurable quantities are raised to an integer power, the same is done to the dimensional symbols attached to those quantities; this corresponds to scalar multiplication in the module.
A basis for such a module of dimensional symbols is called a set of base quantities, and all other vectors are called derived units. As in any module, one may choose different bases, which yields different systems of units (e.g., choosing whether the unit for charge is derived from the unit for current, or vice versa).
The group identity, the dimension of dimensionless quantities, corresponds to the origin in this module, (0, 0, 0).
In certain cases, one can define fractional dimensions, specifically by formally defining fractional powers of one-dimensional vector spaces, like V. However, it is not possible to take arbitrary fractional powers of units, due to representation-theoretic obstructions.
One can work with vector spaces with given dimensions without needing to use units (corresponding to coordinate systems of the vector spaces). For example, given dimensions M and L, one has the vector spaces V and V, and can define V := V ⊗ V as the tensor product. Similarly, the dual space can be interpreted as having "negative" dimensions. This corresponds to the fact that under the natural pairing between a vector space and its dual, the dimensions cancel, leaving a dimensionless scalar.
The set of units of the physical quantities involved in a problem correspond to a set of vectors (or a matrix). The nullity describes some number (e.g., m) of ways in which these vectors can be combined to produce a zero vector. These correspond to producing (from the measurements) a number of dimensionless quantities, {π1, ..., πm}. (In fact these ways completely span the null subspace of another different space, of powers of the measurements.) Every possible way of multiplying (and exponentiating) together the measured quantities to produce something with the same unit as some derived quantity X can be expressed in the general form
Consequently, every possible commensurate equation for the physics of the system can be rewritten in the form
Knowing this restriction can be a powerful tool for obtaining new insight into the system.
The dimension of physical quantities of interest in mechanics can be expressed in terms of base dimensions T, L, and M – these form a 3-dimensional vector space. This is not the only valid choice of base dimensions, but it is the one most commonly used. For example, one might choose force, length and mass as the base dimensions (as some have done), with associated dimensions F, L, M; this corresponds to a different basis, and one may convert between these representations by a change of basis. The choice of the base set of dimensions is thus a convention, with the benefit of increased utility and familiarity. The choice of base dimensions is not entirely arbitrary, because they must form a basis: they must span the space, and be linearly independent.
For example, F, L, M form a set of fundamental dimensions because they form a basis that is equivalent to T, L, M: the former can be expressed as [F = LM/T], L, M, while the latter can be expressed as [T = (LM/F)], L, M.
On the other hand, length, velocity and time (T, L, V) do not form a set of base dimensions for mechanics, for two reasons:
Depending on the field of physics, it may be advantageous to choose one or another extended set of dimensional symbols. In electromagnetism, for example, it may be useful to use dimensions of T, L, M and Q, where Q represents the dimension of electric charge. In thermodynamics, the base set of dimensions is often extended to include a dimension for temperature, Θ. In chemistry, the amount of substance (the number of molecules divided by the Avogadro constant, ≈ 6.02×10 mol) is also defined as a base dimension, N. In the interaction of relativistic plasma with strong laser pulses, a dimensionless relativistic similarity parameter, connected with the symmetry properties of the collisionless Vlasov equation, is constructed from the plasma-, electron- and critical-densities in addition to the electromagnetic vector potential. The choice of the dimensions or even the number of dimensions to be used in different fields of physics is to some extent arbitrary, but consistency in use and ease of communications are common and necessary features.
Bridgman’s theorem restricts the type of function that can be used to define a physical quantity from general (dimensionally compounded) quantities to only products of powers of the quantities, unless some of the independent quantities are algebraically combined to yield dimensionless groups, whose functions are grouped together in the dimensionless numeric multiplying factor. This excludes polynomials of more than one term or transcendental functions not of that form.
Scalar arguments to transcendental functions such as exponential, trigonometric and logarithmic functions, or to inhomogeneous polynomials, must be dimensionless quantities. (Note: this requirement is somewhat relaxed in Siano's orientational analysis described below, in which the square of certain dimensioned quantities are dimensionless.)
While most mathematical identities about dimensionless numbers translate in a straightforward manner to dimensional quantities, care must be taken with logarithms of ratios: the identity log(a/b) = log a − log b, where the logarithm is taken in any base, holds for dimensionless numbers a and b, but it does not hold if a and b are dimensional, because in this case the left-hand side is well-defined but the right-hand side is not.
Similarly, while one can evaluate monomials (x) of dimensional quantities, one cannot evaluate polynomials of mixed degree with dimensionless coefficients on dimensional quantities: for x, the expression (3 m) = 9 m makes sense (as an area), while for x + x, the expression (3 m) + 3 m = 9 m + 3 m does not make sense.
However, polynomials of mixed degree can make sense if the coefficients are suitably chosen physical quantities that are not dimensionless. For example,
This is the height to which an object rises in time t if the acceleration of gravity is 9.8 metres per second per second and the initial upward speed is 500 metres per second. It is not necessary for t to be in seconds. For example, suppose t = 0.01 minutes. Then the first term would be
The value of a dimensional physical quantity Z is written as the product of a unit [Z] within the dimension and a dimensionless numerical value or numerical factor, n.
When like-dimensioned quantities are added or subtracted or compared, it is convenient to express them in the same unit so that the numerical values of these quantities may be directly added or subtracted. But, in concept, there is no problem adding quantities of the same dimension expressed in different units. For example, 1 metre added to 1 foot is a length, but one cannot derive that length by simply adding 1 and 1. A conversion factor, which is a ratio of like-dimensioned quantities and is equal to the dimensionless unity, is needed:
The factor 0.3048 m/ft is identical to the dimensionless 1, so multiplying by this conversion factor changes nothing. Then when adding two quantities of like dimension, but expressed in different units, the appropriate conversion factor, which is essentially the dimensionless 1, is used to convert the quantities to the same unit so that their numerical values can be added or subtracted.
Only in this manner is it meaningful to speak of adding like-dimensioned quantities of differing units.
A quantity equation, also sometimes called a complete equation, is an equation that remains valid independently of the unit of measurement used when expressing the physical quantities.
In contrast, in a numerical-value equation, just the numerical values of the quantities occur, without units. Therefore, it is only valid when each numerical values is referenced to a specific unit.
For example, a quantity equation for displacement d as speed s multiplied by time difference t would be:
for s = 5 m/s, where t and d may be expressed in any units, converted if necessary. In contrast, a corresponding numerical-value equation would be:
where T is the numeric value of t when expressed in seconds and D is the numeric value of d when expressed in metres.
Generally, the use of numerical-value equations is discouraged.
The dimensionless constants that arise in the results obtained, such as the C in the Poiseuille's Law problem and the κ in the spring problems discussed above, come from a more detailed analysis of the underlying physics and often arise from integrating some differential equation. Dimensional analysis itself has little to say about these constants, but it is useful to know that they very often have a magnitude of order unity. This observation can allow one to sometimes make "back of the envelope" calculations about the phenomenon of interest, and therefore be able to more efficiently design experiments to measure it, or to judge whether it is important, etc.
Paradoxically, dimensional analysis can be a useful tool even if all the parameters in the underlying theory are dimensionless, e.g., lattice models such as the Ising model can be used to study phase transitions and critical phenomena. Such models can be formulated in a purely dimensionless way. As we approach the critical point closer and closer, the distance over which the variables in the lattice model are correlated (the so-called correlation length, χ) becomes larger and larger. Now, the correlation length is the relevant length scale related to critical phenomena, so one can, e.g., surmise on "dimensional grounds" that the non-analytical part of the free energy per lattice site should be ~ 1/χ, where d is the dimension of the lattice.
It has been argued by some physicists, e.g., Michael J. Duff, that the laws of physics are inherently dimensionless. The fact that we have assigned incompatible dimensions to Length, Time and Mass is, according to this point of view, just a matter of convention, borne out of the fact that before the advent of modern physics, there was no way to relate mass, length, and time to each other. The three independent dimensionful constants: c, ħ, and G, in the fundamental equations of physics must then be seen as mere conversion factors to convert Mass, Time and Length into each other.
Just as in the case of critical properties of lattice models, one can recover the results of dimensional analysis in the appropriate scaling limit; e.g., dimensional analysis in mechanics can be derived by reinserting the constants ħ, c, and G (but we can now consider them to be dimensionless) and demanding that a nonsingular relation between quantities exists in the limit c → ∞, ħ → 0 and G → 0. In problems involving a gravitational field the latter limit should be taken such that the field stays finite.
Following are tables of commonly occurring expressions in physics, related to the dimensions of energy, momentum, and force.
Dimensional correctness as part of type checking has been studied since 1977. Implementations for Ada and C++ were described in 1985 and 1988. Kennedy's 1996 thesis describes an implementation in Standard ML, and later in F#. There are implementations for Haskell, OCaml, and Rust, Python, and a code checker for Fortran. Griffioen's 2019 thesis extended Kennedy's Hindley–Milner type system to support Hart's matrices. McBride and Nordvall-Forsberg show how to use dependent types to extend type systems for units of measure.
Mathematica 13.2 has a function for transformations with quantities named NondimensionalizationTransform that applies a nondimensionalization transform to an equation. Mathematica also has a function to find the dimensions of a unit such as 1 J named UnitDimensions. Mathematica also has a function that will find dimensionally equivalent combinations of a subset of physical quantities named DimensionalCombations. Mathematica can also factor out certain dimension with UnitDimensions by specifying an argument to the function UnityDimensions. For example, you can use UnityDimensions to factor out angles. In addition to UnitDimensions, Mathematica can find the dimensions of a QuantityVariable with the function QuantityVariableDimensions.
Some discussions of dimensional analysis implicitly describe all quantities as mathematical vectors. (In mathematics scalars are considered a special case of vectors; vectors can be added to or subtracted from other vectors, and, inter alia, multiplied or divided by scalars. If a vector is used to define a position, this assumes an implicit point of reference: an origin. While this is useful and often perfectly adequate, allowing many important errors to be caught, it can fail to model certain aspects of physics. A more rigorous approach requires distinguishing between position and displacement (or moment in time versus duration, or absolute temperature versus temperature change).
Consider points on a line, each with a position with respect to a given origin, and distances among them. Positions and displacements all have units of length, but their meaning is not interchangeable:
This illustrates the subtle distinction between affine quantities (ones modeled by an affine space, such as position) and vector quantities (ones modeled by a vector space, such as displacement).
Properly then, positions have dimension of affine length, while displacements have dimension of vector length. To assign a number to an affine unit, one must not only choose a unit of measurement, but also a point of reference, while to assign a number to a vector unit only requires a unit of measurement.
Thus some physical quantities are better modeled by vectorial quantities while others tend to require affine representation, and the distinction is reflected in their dimensional analysis.
This distinction is particularly important in the case of temperature, for which the numeric value of absolute zero is not the origin 0 in some scales. For absolute zero,
where the symbol ≘ means corresponds to, since although these values on the respective temperature scales correspond, they represent distinct quantities in the same way that the distances from distinct starting points to the same end point are distinct quantities, and cannot in general be equated.
For temperature differences,
(Here °R refers to the Rankine scale, not the Réaumur scale). Unit conversion for temperature differences is simply a matter of multiplying by, e.g., 1 °F / 1 K (although the ratio is not a constant value). But because some of these scales have origins that do not correspond to absolute zero, conversion from one temperature scale to another requires accounting for that. As a result, simple dimensional analysis can lead to errors if it is ambiguous whether 1 K means the absolute temperature equal to −272.15 °C, or the temperature difference equal to 1 °C.
Similar to the issue of a point of reference is the issue of orientation: a displacement in 2 or 3 dimensions is not just a length, but is a length together with a direction. (This issue does not arise in 1 dimension, or rather is equivalent to the distinction between positive and negative.) Thus, to compare or combine two dimensional quantities in a multi-dimensional space, one also needs an orientation: they need to be compared to a frame of reference.
This leads to the extensions discussed below, namely Huntley's directed dimensions and Siano's orientational analysis.
Huntley has pointed out that a dimensional analysis can become more powerful by discovering new independent dimensions in the quantities under consideration, thus increasing the rank m {\displaystyle m} of the dimensional matrix.
He introduced two approaches:
As an example of the usefulness of the first approach, suppose we wish to calculate the distance a cannonball travels when fired with a vertical velocity component V y {\displaystyle V_{\mathrm {y} }} and a horizontal velocity component V x {\displaystyle V_{\mathrm {x} }} , assuming it is fired on a flat surface. Assuming no use of directed lengths, the quantities of interest are then R, the distance travelled, with dimension L, V x {\displaystyle V_{\mathrm {x} }} , V y {\displaystyle V_{\mathrm {y} }} , both dimensioned as TL, and g the downward acceleration of gravity, with dimension TL.
With these four quantities, we may conclude that the equation for the range R may be written:
Or dimensionally
from which we may deduce that a + b + c = 1 {\displaystyle a+b+c=1} and a + b + 2 c = 0 {\displaystyle a+b+2c=0} , which leaves one exponent undetermined. This is to be expected since we have two fundamental dimensions T and L, and four parameters, with one equation.
However, if we use directed length dimensions, then V x {\displaystyle V_{\mathrm {x} }} will be dimensioned as TLx, V y {\displaystyle V_{\mathrm {y} }} as TLy, R as Lx and g as TLy. The dimensional equation becomes:
and we may solve completely as a = 1 {\displaystyle a=1} , b = 1 {\displaystyle b=1} and c = − 1 {\displaystyle c=-1} . The increase in deductive power gained by the use of directed length dimensions is apparent.
Huntley's concept of directed length dimensions however has some serious limitations:
It also is often quite difficult to assign the L, Lx, Ly, Lz, symbols to the physical variables involved in the problem of interest. He invokes a procedure that involves the "symmetry" of the physical problem. This is often very difficult to apply reliably: It is unclear as to what parts of the problem that the notion of "symmetry" is being invoked. Is it the symmetry of the physical body that forces are acting upon, or to the points, lines or areas at which forces are being applied? What if more than one body is involved with different symmetries?
Consider the spherical bubble attached to a cylindrical tube, where one wants the flow rate of air as a function of the pressure difference in the two parts. What are the Huntley extended dimensions of the viscosity of the air contained in the connected parts? What are the extended dimensions of the pressure of the two parts? Are they the same or different? These difficulties are responsible for the limited application of Huntley's directed length dimensions to real problems.
In Huntley's second approach, he holds that it is sometimes useful (e.g., in fluid mechanics and thermodynamics) to distinguish between mass as a measure of inertia (inertial mass), and mass as a measure of the quantity of matter. Quantity of matter is defined by Huntley as a quantity only proportional to inertial mass, while not implicating inertial properties. No further restrictions are added to its definition.
For example, consider the derivation of Poiseuille's Law. We wish to find the rate of mass flow of a viscous fluid through a circular pipe. Without drawing distinctions between inertial and substantial mass, we may choose as the relevant variables:
There are three fundamental variables, so the above five equations will yield two independent dimensionless variables:
If we distinguish between inertial mass with dimension M i {\displaystyle M_{\text{i}}} and quantity of matter with dimension M m {\displaystyle M_{\text{m}}} , then mass flow rate and density will use quantity of matter as the mass parameter, while the pressure gradient and coefficient of viscosity will use inertial mass. We now have four fundamental parameters, and one dimensionless constant, so that the dimensional equation may be written:
where now only C is an undetermined constant (found to be equal to π / 8 {\displaystyle \pi /8} by methods outside of dimensional analysis). This equation may be solved for the mass flow rate to yield Poiseuille's law.
Huntley's recognition of quantity of matter as an independent quantity dimension is evidently successful in the problems where it is applicable, but his definition of quantity of matter is open to interpretation, as it lacks specificity beyond the two requirements he postulated for it. For a given substance, the SI dimension amount of substance, with unit mole, does satisfy Huntley's two requirements as a measure of quantity of matter, and could be used as a quantity of matter in any problem of dimensional analysis where Huntley's concept is applicable.
Angles are, by convention, considered to be dimensionless quantities. As an example, consider again the projectile problem in which a point mass is launched from the origin (x, y) = (0, 0) at a speed v and angle θ above the x-axis, with the force of gravity directed along the negative y-axis. It is desired to find the range R, at which point the mass returns to the x-axis. Conventional analysis will yield the dimensionless variable π = R g/v, but offers no insight into the relationship between R and θ.
Siano has suggested that the directed dimensions of Huntley be replaced by using orientational symbols 1x 1y 1z to denote vector directions, and an orientationless symbol 10. Thus, Huntley's Lx becomes L1x with L specifying the dimension of length, and 1x specifying the orientation. Siano further shows that the orientational symbols have an algebra of their own. Along with the requirement that 1i = 1i, the following multiplication table for the orientation symbols results:
The orientational symbols form a group (the Klein four-group or "Viergruppe"). In this system, scalars always have the same orientation as the identity element, independent of the "symmetry of the problem". Physical quantities that are vectors have the orientation expected: a force or a velocity in the z-direction has the orientation of 1z. For angles, consider an angle θ that lies in the z-plane. Form a right triangle in the z-plane with θ being one of the acute angles. The side of the right triangle adjacent to the angle then has an orientation 1x and the side opposite has an orientation 1y. Since (using ~ to indicate orientational equivalence) tan(θ) = θ + ... ~ 1y/1x we conclude that an angle in the xy-plane must have an orientation 1y/1x = 1z, which is not unreasonable. Analogous reasoning forces the conclusion that sin(θ) has orientation 1z while cos(θ) has orientation 10. These are different, so one concludes (correctly), for example, that there are no solutions of physical equations that are of the form a cos(θ) + b sin(θ), where a and b are real scalars. An expression such as sin ( θ + π / 2 ) = cos ( θ ) {\displaystyle \sin(\theta +\pi /2)=\cos(\theta )} is not dimensionally inconsistent since it is a special case of the sum of angles formula and should properly be written:
which for a = θ {\displaystyle a=\theta } and b = π / 2 {\displaystyle b=\pi /2} yields sin ( θ 1 z + [ π / 2 ] 1 z ) = 1 z cos ( θ 1 z ) {\displaystyle \sin(\theta \,1_{\text{z}}+[\pi /2]\,1_{\text{z}})=1_{\text{z}}\cos(\theta \,1_{\text{z}})} . Siano distinguishes between geometric angles, which have an orientation in 3-dimensional space, and phase angles associated with time-based oscillations, which have no spatial orientation, i.e. the orientation of a phase angle is 1 0 {\displaystyle 1_{0}} .
The assignment of orientational symbols to physical quantities and the requirement that physical equations be orientationally homogeneous can actually be used in a way that is similar to dimensional analysis to derive more information about acceptable solutions of physical problems. In this approach, one solves the dimensional equation as far as one can. If the lowest power of a physical variable is fractional, both sides of the solution is raised to a power such that all powers are integral, putting it into normal form. The orientational equation is then solved to give a more restrictive condition on the unknown powers of the orientational symbols. The solution is then more complete than the one that dimensional analysis alone gives. Often, the added information is that one of the powers of a certain variable is even or odd.
As an example, for the projectile problem, using orientational symbols, θ, being in the xy-plane will thus have dimension 1z and the range of the projectile R will be of the form:
Dimensional homogeneity will now correctly yield a = −1 and b = 2, and orientational homogeneity requires that 1 x / ( 1 y a 1 z c ) = 1 z c + 1 = 1 {\displaystyle 1_{x}/(1_{y}^{a}1_{z}^{c})=1_{z}^{c+1}=1} . In other words, that c must be an odd integer. In fact, the required function of theta will be sin(θ)cos(θ) which is a series consisting of odd powers of θ.
It is seen that the Taylor series of sin(θ) and cos(θ) are orientationally homogeneous using the above multiplication table, while expressions like cos(θ) + sin(θ) and exp(θ) are not, and are (correctly) deemed unphysical.
Siano's orientational analysis is compatible with the conventional conception of angular quantities as being dimensionless, and within orientational analysis, the radian may still be considered a dimensionless unit. The orientational analysis of a quantity equation is carried out separately from the ordinary dimensional analysis, yielding information that supplements the dimensional analysis. | [
{
"paragraph_id": 0,
"text": "In engineering and science, dimensional analysis is the analysis of the relationships between different physical quantities by identifying their base quantities (such as length, mass, time, and electric current) and units of measurement (such as metres and grams) and tracking these dimensions as calculations or comparisons are performed. The term dimensional analysis is also used to refer to conversion of units from one dimensional unit to another, which can be used to evaluate scientific formulae.",
"title": ""
},
{
"paragraph_id": 1,
"text": "Commensurable physical quantities are of the same kind and have the same dimension, and can be directly compared to each other, even if they are expressed in differing units of measurement; e.g., metres and feet, grams and pounds, seconds and years. Incommensurable physical quantities are of different kinds and have different dimensions, and can not be directly compared to each other, no matter what units they are expressed in, e.g. metres and grams, seconds and grams, metres and seconds. For example, asking whether a gram is larger than an hour is meaningless.",
"title": ""
},
{
"paragraph_id": 2,
"text": "Any physically meaningful equation, or inequality, must have the same dimensions on its left and right sides, a property known as dimensional homogeneity. Checking for dimensional homogeneity is a common application of dimensional analysis, serving as a plausibility check on derived equations and computations. It also serves as a guide and constraint in deriving equations that may describe a physical system in the absence of a more rigorous derivation.",
"title": ""
},
{
"paragraph_id": 3,
"text": "The concept of physical dimension, and of dimensional analysis, was introduced by Joseph Fourier in 1822.",
"title": ""
},
{
"paragraph_id": 4,
"text": "The Buckingham π theorem describes how every physically meaningful equation involving n variables can be equivalently rewritten as an equation of n − m dimensionless parameters, where m is the rank of the dimensional matrix. Furthermore, and most importantly, it provides a method for computing these dimensionless parameters from the given variables.",
"title": "Formulation"
},
{
"paragraph_id": 5,
"text": "A dimensional equation can have the dimensions reduced or eliminated through nondimensionalization, which begins with dimensional analysis, and involves scaling quantities by characteristic units of a system or physical constants of nature. This may give insight into the fundamental properties of the system, as illustrated in the examples below.",
"title": "Formulation"
},
{
"paragraph_id": 6,
"text": "The dimension of a physical quantity can be expressed as a product of the base physical dimensions such as length, mass and time, each raised to an integer (and occasionally rational) power. The dimension of a physical quantity is more fundamental than some scale or unit used to express the amount of that physical quantity. For example, mass is a dimension, while the kilogram is a particular reference quantity chosen to express a quantity of mass. The choice of unit is arbitrary, and its choice is often based on historical precedent. Natural units, being based on only universal constants, may be thought of as being \"less arbitrary\".",
"title": "Formulation"
},
{
"paragraph_id": 7,
"text": "There are many possible choices of base physical dimensions. The SI standard selects the following dimensions and corresponding dimension symbols:",
"title": "Formulation"
},
{
"paragraph_id": 8,
"text": "The symbols are by convention usually written in roman sans serif typeface. Mathematically, the dimension of the quantity Q is given by",
"title": "Formulation"
},
{
"paragraph_id": 9,
"text": "where a, b, c, d, e, f, g are the dimensional exponents. Other physical quantities could be defined as the base quantities, as long as they form a linearly independent basis – for instance, one could replace the dimension (I) of electric current of the SI basis with a dimension (Q) of electric charge, since Q = TI.",
"title": "Formulation"
},
{
"paragraph_id": 10,
"text": "A quantity that has only b ≠ 0 (with all other exponents zero) is known as a geometric quantity. A quantity that has only both a ≠ 0 and b ≠ 0 is known as a kinematic quantity. A quantity that has only all of a ≠ 0, b ≠ 0, and c ≠ 0 is known as a dynamic quantity. A quantity that has all exponents null is said to have dimension one.",
"title": "Formulation"
},
{
"paragraph_id": 11,
"text": "The unit chosen to express a physical quantity and its dimension are related, but not identical concepts. The units of a physical quantity are defined by convention and related to some standard; e.g., length may have units of metres, feet, inches, miles or micrometres; but any length always has a dimension of L, no matter what units of length are chosen to express it. Two different units of the same physical quantity have conversion factors that relate them. For example, 1 in = 2.54 cm; in this case 2.54 cm/in is the conversion factor, which is itself dimensionless. Therefore, multiplying by that conversion factor does not change the dimensions of a physical quantity.",
"title": "Formulation"
},
{
"paragraph_id": 12,
"text": "There are also physicists who have cast doubt on the very existence of incompatible fundamental dimensions of physical quantity, although this does not invalidate the usefulness of dimensional analysis.",
"title": "Formulation"
},
{
"paragraph_id": 13,
"text": "As examples, the dimension of the physical quantity speed v is",
"title": "Formulation"
},
{
"paragraph_id": 14,
"text": "The dimension of the physical quantity force F is",
"title": "Formulation"
},
{
"paragraph_id": 15,
"text": "The dimension of the physical quantity pressure P is",
"title": "Formulation"
},
{
"paragraph_id": 16,
"text": "The dimension of the physical quantity energy E is",
"title": "Formulation"
},
{
"paragraph_id": 17,
"text": "The dimension of the physical quantity power P is",
"title": "Formulation"
},
{
"paragraph_id": 18,
"text": "The dimension of the physical quantity electric charge Q is",
"title": "Formulation"
},
{
"paragraph_id": 19,
"text": "The dimension of the physical quantity electric potential difference V is",
"title": "Formulation"
},
{
"paragraph_id": 20,
"text": "The dimension of the physical quantity capacitance C is",
"title": "Formulation"
},
{
"paragraph_id": 21,
"text": "In dimensional analysis, Rayleigh's method is a conceptual tool used in physics, chemistry, and engineering. It expresses a functional relationship of some variables in the form of an exponential equation. It was named after Lord Rayleigh.",
"title": "Formulation"
},
{
"paragraph_id": 22,
"text": "The method involves the following steps:",
"title": "Formulation"
},
{
"paragraph_id": 23,
"text": "As a drawback, Rayleigh's method does not provide any information regarding number of dimensionless groups to be obtained as a result of dimensional analysis.",
"title": "Formulation"
},
{
"paragraph_id": 24,
"text": "Many parameters and measurements in the physical sciences and engineering are expressed as a concrete number—a numerical quantity and a corresponding dimensional unit. Often a quantity is expressed in terms of several other quantities; for example, speed is a combination of length and time, e.g. 60 kilometres per hour or 1.4 kilometres per second. Compound relations with \"per\" are expressed with division, e.g. 60 km/h. Other relations can involve multiplication (often shown with a centered dot or juxtaposition), powers (like m for square metres), or combinations thereof.",
"title": "Concrete numbers and base units"
},
{
"paragraph_id": 25,
"text": "A set of base units for a system of measurement is a conventionally chosen set of units, none of which can be expressed as a combination of the others and in terms of which all the remaining units of the system can be expressed. For example, units for length and time are normally chosen as base units. Units for volume, however, can be factored into the base units of length (m), thus they are considered derived or compound units.",
"title": "Concrete numbers and base units"
},
{
"paragraph_id": 26,
"text": "Sometimes the names of units obscure the fact that they are derived units. For example, a newton (N) is a unit of force, which may be expressed as the product of mass (with unit kg) and acceleration (with unit m⋅s). The newton is defined as 1 N = 1 kg⋅m⋅s.",
"title": "Concrete numbers and base units"
},
{
"paragraph_id": 27,
"text": "Percentages are dimensionless quantities, since they are ratios of two quantities with the same dimensions. In other words, the % sign can be read as \"hundredths\", since 1% = 1/100.",
"title": "Concrete numbers and base units"
},
{
"paragraph_id": 28,
"text": "Taking a derivative with respect to a quantity divides the dimension by the dimension of the variable that is differentiated with respect to. Thus:",
"title": "Concrete numbers and base units"
},
{
"paragraph_id": 29,
"text": "Likewise, taking an integral adds the dimension of the variable one is integrating with respect to, but in the numerator.",
"title": "Concrete numbers and base units"
},
{
"paragraph_id": 30,
"text": "In economics, one distinguishes between stocks and flows: a stock has a unit (say, widgets or dollars), while a flow is a derivative of a stock, and has a unit of the form of this unit divided by one of time (say, dollars/year).",
"title": "Concrete numbers and base units"
},
{
"paragraph_id": 31,
"text": "In some contexts, dimensional quantities are expressed as dimensionless quantities or percentages by omitting some dimensions. For example, debt-to-GDP ratios are generally expressed as percentages: total debt outstanding (dimension of currency) divided by annual GDP (dimension of currency)—but one may argue that, in comparing a stock to a flow, annual GDP should have dimensions of currency/time (dollars/year, for instance) and thus debt-to-GDP should have the unit year, which indicates that debt-to-GDP is the number of years needed for a constant GDP to pay the debt, if all GDP is spent on the debt and the debt is otherwise unchanged.",
"title": "Concrete numbers and base units"
},
{
"paragraph_id": 32,
"text": "The most basic rule of dimensional analysis is that of dimensional homogeneity.",
"title": "Dimensional homogeneity (commensurability) "
},
{
"paragraph_id": 33,
"text": "However, the dimensions form an abelian group under multiplication, so:",
"title": "Dimensional homogeneity (commensurability) "
},
{
"paragraph_id": 34,
"text": "For example, it makes no sense to ask whether 1 hour is more, the same, or less than 1 kilometre, as these have different dimensions, nor to add 1 hour to 1 kilometre. However, it makes sense to ask whether 1 mile is more, the same, or less than 1 kilometre, being the same dimension of physical quantity even though the units are different. On the other hand, if an object travels 100 km in 2 hours, one may divide these and conclude that the object's average speed was 50 km/h.",
"title": "Dimensional homogeneity (commensurability) "
},
{
"paragraph_id": 35,
"text": "The rule implies that in a physically meaningful expression only quantities of the same dimension can be added, subtracted, or compared. For example, if mman, mrat and Lman denote, respectively, the mass of some man, the mass of a rat and the length of that man, the dimensionally homogeneous expression mman + mrat is meaningful, but the heterogeneous expression mman + Lman is meaningless. However, mman/Lman is fine. Thus, dimensional analysis may be used as a sanity check of physical equations: the two sides of any equation must be commensurable or have the same dimensions.",
"title": "Dimensional homogeneity (commensurability) "
},
{
"paragraph_id": 36,
"text": "Even when two physical quantities have identical dimensions, it may nevertheless be meaningless to compare or add them. For example, although torque and energy share the dimension TLM, they are fundamentally different physical quantities.",
"title": "Dimensional homogeneity (commensurability) "
},
{
"paragraph_id": 37,
"text": "To compare, add, or subtract quantities with the same dimensions but expressed in different units, the standard procedure is first to convert them all to the same unit. For example, to compare 32 metres with 35 yards, use 1 yard = 0.9144 m to convert 35 yards to 32.004 m.",
"title": "Dimensional homogeneity (commensurability) "
},
{
"paragraph_id": 38,
"text": "A related principle is that any physical law that accurately describes the real world must be independent of the units used to measure the physical variables. For example, Newton's laws of motion must hold true whether distance is measured in miles or kilometres. This principle gives rise to the form that a conversion factor between a unit that measures the same dimension must take: multiplication by a simple constant. It also ensures equivalence; for example, if two buildings are the same height in feet, then they must be the same height in metres.",
"title": "Dimensional homogeneity (commensurability) "
},
{
"paragraph_id": 39,
"text": "In dimensional analysis, a ratio which converts one unit of measure into another without changing the quantity is called a conversion factor. For example, kPa and bar are both units of pressure, and 100 kPa = 1 bar. The rules of algebra allow both sides of an equation to be divided by the same expression, so this is equivalent to 100 kPa / 1 bar = 1. Since any quantity can be multiplied by 1 without changing it, the expression \"100 kPa / 1 bar\" can be used to convert from bars to kPa by multiplying it with the quantity to be converted, including the unit. For example, 5 bar × 100 kPa / 1 bar = 500 kPa because 5 × 100 / 1 = 500, and bar/bar cancels out, so 5 bar = 500 kPa.",
"title": "Conversion factor"
},
{
"paragraph_id": 40,
"text": "Dimensional analysis is most often used in physics and chemistry – and in the mathematics thereof – but finds some applications outside of those fields as well.",
"title": "Applications"
},
{
"paragraph_id": 41,
"text": "A simple application of dimensional analysis to mathematics is in computing the form of the volume of an n-ball (the solid ball in n dimensions), or the area of its surface, the n-sphere: being an n-dimensional figure, the volume scales as x, while the surface area, being (n − 1)-dimensional, scales as x. Thus the volume of the n-ball in terms of the radius is Cr, for some constant C. Determining the constant takes more involved mathematics, but the form can be deduced and checked by dimensional analysis alone.",
"title": "Applications"
},
{
"paragraph_id": 42,
"text": "In finance, economics, and accounting, dimensional analysis is most commonly referred to in terms of the distinction between stocks and flows. More generally, dimensional analysis is used in interpreting various financial ratios, economics ratios, and accounting ratios.",
"title": "Applications"
},
{
"paragraph_id": 43,
"text": "In fluid mechanics, dimensional analysis is performed to obtain dimensionless pi terms or groups. According to the principles of dimensional analysis, any prototype can be described by a series of these terms or groups that describe the behaviour of the system. Using suitable pi terms or groups, it is possible to develop a similar set of pi terms for a model that has the same dimensional relationships. In other words, pi terms provide a shortcut to developing a model representing a certain prototype. Common dimensionless groups in fluid mechanics include:",
"title": "Applications"
},
{
"paragraph_id": 44,
"text": "The origins of dimensional analysis have been disputed by historians. The first written application of dimensional analysis has been credited to François Daviet, a student of Lagrange, in a 1799 article at the Turin Academy of Science.",
"title": "History"
},
{
"paragraph_id": 45,
"text": "This led to the conclusion that meaningful laws must be homogeneous equations in their various units of measurement, a result which was eventually later formalized in the Buckingham π theorem. Simeon Poisson also treated the same problem of the parallelogram law by Daviet, in his treatise of 1811 and 1833 (vol I, p. 39). In the second edition of 1833, Poisson explicitly introduces the term dimension instead of the Daviet homogeneity.",
"title": "History"
},
{
"paragraph_id": 46,
"text": "In 1822, the important Napoleonic scientist Joseph Fourier made the first credited important contributions based on the idea that physical laws like F = ma should be independent of the units employed to measure the physical variables.",
"title": "History"
},
{
"paragraph_id": 47,
"text": "James Clerk Maxwell played a major role in establishing modern use of dimensional analysis by distinguishing mass, length, and time as fundamental units, while referring to other units as derived. Although Maxwell defined length, time and mass to be \"the three fundamental units\", he also noted that gravitational mass can be derived from length and time by assuming a form of Newton's law of universal gravitation in which the gravitational constant G is taken as unity, thereby defining M = TL. By assuming a form of Coulomb's law in which the Coulomb constant ke is taken as unity, Maxwell then determined that the dimensions of an electrostatic unit of charge were Q = TLM, which, after substituting his M = TL equation for mass, results in charge having the same dimensions as mass, viz. Q = TL.",
"title": "History"
},
{
"paragraph_id": 48,
"text": "Dimensional analysis is also used to derive relationships between the physical quantities that are involved in a particular phenomenon that one wishes to understand and characterize. It was used for the first time in this way in 1872 by Lord Rayleigh, who was trying to understand why the sky is blue. Rayleigh first published the technique in his 1877 book The Theory of Sound.",
"title": "History"
},
{
"paragraph_id": 49,
"text": "The original meaning of the word dimension, in Fourier's Theorie de la Chaleur, was the numerical value of the exponents of the base units. For example, acceleration was considered to have the dimension 1 with respect to the unit of length, and the dimension −2 with respect to the unit of time. This was slightly changed by Maxwell, who said the dimensions of acceleration are TL, instead of just the exponents.",
"title": "History"
},
{
"paragraph_id": 50,
"text": "What is the period of oscillation T of a mass m attached to an ideal linear spring with spring constant k suspended in gravity of strength g? That period is the solution for T of some dimensionless equation in the variables T, m, k, and g. The four quantities have the following dimensions: T [T]; m [M]; k [M/T]; and g [L/T]. From these we can form only one dimensionless product of powers of our chosen variables, G1 = Tk/m [T · M/T / M = 1], and putting G1 = C for some dimensionless constant C gives the dimensionless equation sought. The dimensionless product of powers of variables is sometimes referred to as a dimensionless group of variables; here the term \"group\" means \"collection\" rather than mathematical group. They are often called dimensionless numbers as well.",
"title": "Examples"
},
{
"paragraph_id": 51,
"text": "The variable g does not occur in the group. It is easy to see that it is impossible to form a dimensionless product of powers that combines g with k, m, and T, because g is the only quantity that involves the dimension L. This implies that in this problem the g is irrelevant. Dimensional analysis can sometimes yield strong statements about the irrelevance of some quantities in a problem, or the need for additional parameters. If we have chosen enough variables to properly describe the problem, then from this argument we can conclude that the period of the mass on the spring is independent of g: it is the same on the earth or the moon. The equation demonstrating the existence of a product of powers for our problem can be written in an entirely equivalent way: T = κ m k {\\displaystyle T=\\kappa {\\sqrt {\\tfrac {m}{k}}}} , for some dimensionless constant κ (equal to C {\\displaystyle {\\sqrt {C}}} from the original dimensionless equation).",
"title": "Examples"
},
{
"paragraph_id": 52,
"text": "When faced with a case where dimensional analysis rejects a variable (g, here) that one intuitively expects to belong in a physical description of the situation, another possibility is that the rejected variable is in fact relevant, but that some other relevant variable has been omitted, which might combine with the rejected variable to form a dimensionless quantity. That is, however, not the case here.",
"title": "Examples"
},
{
"paragraph_id": 53,
"text": "When dimensional analysis yields only one dimensionless group, as here, there are no unknown functions, and the solution is said to be \"complete\" – although it still may involve unknown dimensionless constants, such as κ.",
"title": "Examples"
},
{
"paragraph_id": 54,
"text": "Consider the case of a vibrating wire of length ℓ (L) vibrating with an amplitude A (L). The wire has a linear density ρ (M/L) and is under tension s (LM/T), and we want to know the energy E (LM/T) in the wire. Let π1 and π2 be two dimensionless products of powers of the variables chosen, given by",
"title": "Examples"
},
{
"paragraph_id": 55,
"text": "The linear density of the wire is not involved. The two groups found can be combined into an equivalent form as an equation",
"title": "Examples"
},
{
"paragraph_id": 56,
"text": "where F is some unknown function, or, equivalently as",
"title": "Examples"
},
{
"paragraph_id": 57,
"text": "where f is some other unknown function. Here the unknown function implies that our solution is now incomplete, but dimensional analysis has given us something that may not have been obvious: the energy is proportional to the first power of the tension. Barring further analytical analysis, we might proceed to experiments to discover the form for the unknown function f. But our experiments are simpler than in the absence of dimensional analysis. We'd perform none to verify that the energy is proportional to the tension. Or perhaps we might guess that the energy is proportional to ℓ, and so infer that E = ℓs. The power of dimensional analysis as an aid to experiment and forming hypotheses becomes evident.",
"title": "Examples"
},
{
"paragraph_id": 58,
"text": "The power of dimensional analysis really becomes apparent when it is applied to situations, unlike those given above, that are more complicated, the set of variables involved are not apparent, and the underlying equations hopelessly complex. Consider, for example, a small pebble sitting on the bed of a river. If the river flows fast enough, it will actually raise the pebble and cause it to flow along with the water. At what critical velocity will this occur? Sorting out the guessed variables is not so easy as before. But dimensional analysis can be a powerful aid in understanding problems like this, and is usually the very first tool to be applied to complex problems where the underlying equations and constraints are poorly understood. In such cases, the answer may depend on a dimensionless number such as the Reynolds number, which may be interpreted by dimensional analysis.",
"title": "Examples"
},
{
"paragraph_id": 59,
"text": "Consider the case of a thin, solid, parallel-sided rotating disc of axial thickness t (L) and radius R (L). The disc has a density ρ (M/L), rotates at an angular velocity ω (T) and this leads to a stress S (TLM) in the material. There is a theoretical linear elastic solution, given by Lame, to this problem when the disc is thin relative to its radius, the faces of the disc are free to move axially, and the plane stress constitutive relations can be assumed to be valid. As the disc becomes thicker relative to the radius then the plane stress solution breaks down. If the disc is restrained axially on its free faces then a state of plane strain will occur. However, if this is not the case then the state of stress may only be determined though consideration of three-dimensional elasticity and there is no known theoretical solution for this case. An engineer might, therefore, be interested in establishing a relationship between the five variables. Dimensional analysis for this case leads to the following (5 − 3 = 2) non-dimensional groups:",
"title": "Examples"
},
{
"paragraph_id": 60,
"text": "Through the use of numerical experiments using, for example, the finite element method, the nature of the relationship between the two non-dimensional groups can be obtained as shown in the figure. As this problem only involves two non-dimensional groups, the complete picture is provided in a single plot and this can be used as a design/assessment chart for rotating discs.",
"title": "Examples"
},
{
"paragraph_id": 61,
"text": "The dimensions that can be formed from a given collection of basic physical dimensions, such as T, L, and M, form an abelian group: The identity is written as 1; L = 1, and the inverse of L is 1/L or L. L raised to any integer power p is a member of the group, having an inverse of L or 1/L. The operation of the group is multiplication, having the usual rules for handling exponents (L × L = L). Physically, 1/L can be interpreted as reciprocal length, and 1/T as reciprocal time (see reciprocal second).",
"title": "Properties"
},
{
"paragraph_id": 62,
"text": "An abelian group is equivalent to a module over the integers, with the dimensional symbol TLM corresponding to the tuple (i, j, k). When physical measured quantities (be they like-dimensioned or unlike-dimensioned) are multiplied or divided by one other, their dimensional units are likewise multiplied or divided; this corresponds to addition or subtraction in the module. When measurable quantities are raised to an integer power, the same is done to the dimensional symbols attached to those quantities; this corresponds to scalar multiplication in the module.",
"title": "Properties"
},
{
"paragraph_id": 63,
"text": "A basis for such a module of dimensional symbols is called a set of base quantities, and all other vectors are called derived units. As in any module, one may choose different bases, which yields different systems of units (e.g., choosing whether the unit for charge is derived from the unit for current, or vice versa).",
"title": "Properties"
},
{
"paragraph_id": 64,
"text": "The group identity, the dimension of dimensionless quantities, corresponds to the origin in this module, (0, 0, 0).",
"title": "Properties"
},
{
"paragraph_id": 65,
"text": "In certain cases, one can define fractional dimensions, specifically by formally defining fractional powers of one-dimensional vector spaces, like V. However, it is not possible to take arbitrary fractional powers of units, due to representation-theoretic obstructions.",
"title": "Properties"
},
{
"paragraph_id": 66,
"text": "One can work with vector spaces with given dimensions without needing to use units (corresponding to coordinate systems of the vector spaces). For example, given dimensions M and L, one has the vector spaces V and V, and can define V := V ⊗ V as the tensor product. Similarly, the dual space can be interpreted as having \"negative\" dimensions. This corresponds to the fact that under the natural pairing between a vector space and its dual, the dimensions cancel, leaving a dimensionless scalar.",
"title": "Properties"
},
{
"paragraph_id": 67,
"text": "The set of units of the physical quantities involved in a problem correspond to a set of vectors (or a matrix). The nullity describes some number (e.g., m) of ways in which these vectors can be combined to produce a zero vector. These correspond to producing (from the measurements) a number of dimensionless quantities, {π1, ..., πm}. (In fact these ways completely span the null subspace of another different space, of powers of the measurements.) Every possible way of multiplying (and exponentiating) together the measured quantities to produce something with the same unit as some derived quantity X can be expressed in the general form",
"title": "Properties"
},
{
"paragraph_id": 68,
"text": "Consequently, every possible commensurate equation for the physics of the system can be rewritten in the form",
"title": "Properties"
},
{
"paragraph_id": 69,
"text": "Knowing this restriction can be a powerful tool for obtaining new insight into the system.",
"title": "Properties"
},
{
"paragraph_id": 70,
"text": "The dimension of physical quantities of interest in mechanics can be expressed in terms of base dimensions T, L, and M – these form a 3-dimensional vector space. This is not the only valid choice of base dimensions, but it is the one most commonly used. For example, one might choose force, length and mass as the base dimensions (as some have done), with associated dimensions F, L, M; this corresponds to a different basis, and one may convert between these representations by a change of basis. The choice of the base set of dimensions is thus a convention, with the benefit of increased utility and familiarity. The choice of base dimensions is not entirely arbitrary, because they must form a basis: they must span the space, and be linearly independent.",
"title": "Properties"
},
{
"paragraph_id": 71,
"text": "For example, F, L, M form a set of fundamental dimensions because they form a basis that is equivalent to T, L, M: the former can be expressed as [F = LM/T], L, M, while the latter can be expressed as [T = (LM/F)], L, M.",
"title": "Properties"
},
{
"paragraph_id": 72,
"text": "On the other hand, length, velocity and time (T, L, V) do not form a set of base dimensions for mechanics, for two reasons:",
"title": "Properties"
},
{
"paragraph_id": 73,
"text": "Depending on the field of physics, it may be advantageous to choose one or another extended set of dimensional symbols. In electromagnetism, for example, it may be useful to use dimensions of T, L, M and Q, where Q represents the dimension of electric charge. In thermodynamics, the base set of dimensions is often extended to include a dimension for temperature, Θ. In chemistry, the amount of substance (the number of molecules divided by the Avogadro constant, ≈ 6.02×10 mol) is also defined as a base dimension, N. In the interaction of relativistic plasma with strong laser pulses, a dimensionless relativistic similarity parameter, connected with the symmetry properties of the collisionless Vlasov equation, is constructed from the plasma-, electron- and critical-densities in addition to the electromagnetic vector potential. The choice of the dimensions or even the number of dimensions to be used in different fields of physics is to some extent arbitrary, but consistency in use and ease of communications are common and necessary features.",
"title": "Properties"
},
{
"paragraph_id": 74,
"text": "Bridgman’s theorem restricts the type of function that can be used to define a physical quantity from general (dimensionally compounded) quantities to only products of powers of the quantities, unless some of the independent quantities are algebraically combined to yield dimensionless groups, whose functions are grouped together in the dimensionless numeric multiplying factor. This excludes polynomials of more than one term or transcendental functions not of that form.",
"title": "Properties"
},
{
"paragraph_id": 75,
"text": "Scalar arguments to transcendental functions such as exponential, trigonometric and logarithmic functions, or to inhomogeneous polynomials, must be dimensionless quantities. (Note: this requirement is somewhat relaxed in Siano's orientational analysis described below, in which the square of certain dimensioned quantities are dimensionless.)",
"title": "Properties"
},
{
"paragraph_id": 76,
"text": "While most mathematical identities about dimensionless numbers translate in a straightforward manner to dimensional quantities, care must be taken with logarithms of ratios: the identity log(a/b) = log a − log b, where the logarithm is taken in any base, holds for dimensionless numbers a and b, but it does not hold if a and b are dimensional, because in this case the left-hand side is well-defined but the right-hand side is not.",
"title": "Properties"
},
{
"paragraph_id": 77,
"text": "Similarly, while one can evaluate monomials (x) of dimensional quantities, one cannot evaluate polynomials of mixed degree with dimensionless coefficients on dimensional quantities: for x, the expression (3 m) = 9 m makes sense (as an area), while for x + x, the expression (3 m) + 3 m = 9 m + 3 m does not make sense.",
"title": "Properties"
},
{
"paragraph_id": 78,
"text": "However, polynomials of mixed degree can make sense if the coefficients are suitably chosen physical quantities that are not dimensionless. For example,",
"title": "Properties"
},
{
"paragraph_id": 79,
"text": "This is the height to which an object rises in time t if the acceleration of gravity is 9.8 metres per second per second and the initial upward speed is 500 metres per second. It is not necessary for t to be in seconds. For example, suppose t = 0.01 minutes. Then the first term would be",
"title": "Properties"
},
{
"paragraph_id": 80,
"text": "The value of a dimensional physical quantity Z is written as the product of a unit [Z] within the dimension and a dimensionless numerical value or numerical factor, n.",
"title": "Properties"
},
{
"paragraph_id": 81,
"text": "When like-dimensioned quantities are added or subtracted or compared, it is convenient to express them in the same unit so that the numerical values of these quantities may be directly added or subtracted. But, in concept, there is no problem adding quantities of the same dimension expressed in different units. For example, 1 metre added to 1 foot is a length, but one cannot derive that length by simply adding 1 and 1. A conversion factor, which is a ratio of like-dimensioned quantities and is equal to the dimensionless unity, is needed:",
"title": "Properties"
},
{
"paragraph_id": 82,
"text": "The factor 0.3048 m/ft is identical to the dimensionless 1, so multiplying by this conversion factor changes nothing. Then when adding two quantities of like dimension, but expressed in different units, the appropriate conversion factor, which is essentially the dimensionless 1, is used to convert the quantities to the same unit so that their numerical values can be added or subtracted.",
"title": "Properties"
},
{
"paragraph_id": 83,
"text": "Only in this manner is it meaningful to speak of adding like-dimensioned quantities of differing units.",
"title": "Properties"
},
{
"paragraph_id": 84,
"text": "A quantity equation, also sometimes called a complete equation, is an equation that remains valid independently of the unit of measurement used when expressing the physical quantities.",
"title": "Properties"
},
{
"paragraph_id": 85,
"text": "In contrast, in a numerical-value equation, just the numerical values of the quantities occur, without units. Therefore, it is only valid when each numerical values is referenced to a specific unit.",
"title": "Properties"
},
{
"paragraph_id": 86,
"text": "For example, a quantity equation for displacement d as speed s multiplied by time difference t would be:",
"title": "Properties"
},
{
"paragraph_id": 87,
"text": "for s = 5 m/s, where t and d may be expressed in any units, converted if necessary. In contrast, a corresponding numerical-value equation would be:",
"title": "Properties"
},
{
"paragraph_id": 88,
"text": "where T is the numeric value of t when expressed in seconds and D is the numeric value of d when expressed in metres.",
"title": "Properties"
},
{
"paragraph_id": 89,
"text": "Generally, the use of numerical-value equations is discouraged.",
"title": "Properties"
},
{
"paragraph_id": 90,
"text": "The dimensionless constants that arise in the results obtained, such as the C in the Poiseuille's Law problem and the κ in the spring problems discussed above, come from a more detailed analysis of the underlying physics and often arise from integrating some differential equation. Dimensional analysis itself has little to say about these constants, but it is useful to know that they very often have a magnitude of order unity. This observation can allow one to sometimes make \"back of the envelope\" calculations about the phenomenon of interest, and therefore be able to more efficiently design experiments to measure it, or to judge whether it is important, etc.",
"title": "Dimensionless concepts"
},
{
"paragraph_id": 91,
"text": "Paradoxically, dimensional analysis can be a useful tool even if all the parameters in the underlying theory are dimensionless, e.g., lattice models such as the Ising model can be used to study phase transitions and critical phenomena. Such models can be formulated in a purely dimensionless way. As we approach the critical point closer and closer, the distance over which the variables in the lattice model are correlated (the so-called correlation length, χ) becomes larger and larger. Now, the correlation length is the relevant length scale related to critical phenomena, so one can, e.g., surmise on \"dimensional grounds\" that the non-analytical part of the free energy per lattice site should be ~ 1/χ, where d is the dimension of the lattice.",
"title": "Dimensionless concepts"
},
{
"paragraph_id": 92,
"text": "It has been argued by some physicists, e.g., Michael J. Duff, that the laws of physics are inherently dimensionless. The fact that we have assigned incompatible dimensions to Length, Time and Mass is, according to this point of view, just a matter of convention, borne out of the fact that before the advent of modern physics, there was no way to relate mass, length, and time to each other. The three independent dimensionful constants: c, ħ, and G, in the fundamental equations of physics must then be seen as mere conversion factors to convert Mass, Time and Length into each other.",
"title": "Dimensionless concepts"
},
{
"paragraph_id": 93,
"text": "Just as in the case of critical properties of lattice models, one can recover the results of dimensional analysis in the appropriate scaling limit; e.g., dimensional analysis in mechanics can be derived by reinserting the constants ħ, c, and G (but we can now consider them to be dimensionless) and demanding that a nonsingular relation between quantities exists in the limit c → ∞, ħ → 0 and G → 0. In problems involving a gravitational field the latter limit should be taken such that the field stays finite.",
"title": "Dimensionless concepts"
},
{
"paragraph_id": 94,
"text": "Following are tables of commonly occurring expressions in physics, related to the dimensions of energy, momentum, and force.",
"title": "Dimensional equivalences"
},
{
"paragraph_id": 95,
"text": "Dimensional correctness as part of type checking has been studied since 1977. Implementations for Ada and C++ were described in 1985 and 1988. Kennedy's 1996 thesis describes an implementation in Standard ML, and later in F#. There are implementations for Haskell, OCaml, and Rust, Python, and a code checker for Fortran. Griffioen's 2019 thesis extended Kennedy's Hindley–Milner type system to support Hart's matrices. McBride and Nordvall-Forsberg show how to use dependent types to extend type systems for units of measure.",
"title": "Programming languages"
},
{
"paragraph_id": 96,
"text": "Mathematica 13.2 has a function for transformations with quantities named NondimensionalizationTransform that applies a nondimensionalization transform to an equation. Mathematica also has a function to find the dimensions of a unit such as 1 J named UnitDimensions. Mathematica also has a function that will find dimensionally equivalent combinations of a subset of physical quantities named DimensionalCombations. Mathematica can also factor out certain dimension with UnitDimensions by specifying an argument to the function UnityDimensions. For example, you can use UnityDimensions to factor out angles. In addition to UnitDimensions, Mathematica can find the dimensions of a QuantityVariable with the function QuantityVariableDimensions.",
"title": "Programming languages"
},
{
"paragraph_id": 97,
"text": "Some discussions of dimensional analysis implicitly describe all quantities as mathematical vectors. (In mathematics scalars are considered a special case of vectors; vectors can be added to or subtracted from other vectors, and, inter alia, multiplied or divided by scalars. If a vector is used to define a position, this assumes an implicit point of reference: an origin. While this is useful and often perfectly adequate, allowing many important errors to be caught, it can fail to model certain aspects of physics. A more rigorous approach requires distinguishing between position and displacement (or moment in time versus duration, or absolute temperature versus temperature change).",
"title": "Geometry: position vs. displacement"
},
{
"paragraph_id": 98,
"text": "Consider points on a line, each with a position with respect to a given origin, and distances among them. Positions and displacements all have units of length, but their meaning is not interchangeable:",
"title": "Geometry: position vs. displacement"
},
{
"paragraph_id": 99,
"text": "This illustrates the subtle distinction between affine quantities (ones modeled by an affine space, such as position) and vector quantities (ones modeled by a vector space, such as displacement).",
"title": "Geometry: position vs. displacement"
},
{
"paragraph_id": 100,
"text": "Properly then, positions have dimension of affine length, while displacements have dimension of vector length. To assign a number to an affine unit, one must not only choose a unit of measurement, but also a point of reference, while to assign a number to a vector unit only requires a unit of measurement.",
"title": "Geometry: position vs. displacement"
},
{
"paragraph_id": 101,
"text": "Thus some physical quantities are better modeled by vectorial quantities while others tend to require affine representation, and the distinction is reflected in their dimensional analysis.",
"title": "Geometry: position vs. displacement"
},
{
"paragraph_id": 102,
"text": "This distinction is particularly important in the case of temperature, for which the numeric value of absolute zero is not the origin 0 in some scales. For absolute zero,",
"title": "Geometry: position vs. displacement"
},
{
"paragraph_id": 103,
"text": "where the symbol ≘ means corresponds to, since although these values on the respective temperature scales correspond, they represent distinct quantities in the same way that the distances from distinct starting points to the same end point are distinct quantities, and cannot in general be equated.",
"title": "Geometry: position vs. displacement"
},
{
"paragraph_id": 104,
"text": "For temperature differences,",
"title": "Geometry: position vs. displacement"
},
{
"paragraph_id": 105,
"text": "(Here °R refers to the Rankine scale, not the Réaumur scale). Unit conversion for temperature differences is simply a matter of multiplying by, e.g., 1 °F / 1 K (although the ratio is not a constant value). But because some of these scales have origins that do not correspond to absolute zero, conversion from one temperature scale to another requires accounting for that. As a result, simple dimensional analysis can lead to errors if it is ambiguous whether 1 K means the absolute temperature equal to −272.15 °C, or the temperature difference equal to 1 °C.",
"title": "Geometry: position vs. displacement"
},
{
"paragraph_id": 106,
"text": "Similar to the issue of a point of reference is the issue of orientation: a displacement in 2 or 3 dimensions is not just a length, but is a length together with a direction. (This issue does not arise in 1 dimension, or rather is equivalent to the distinction between positive and negative.) Thus, to compare or combine two dimensional quantities in a multi-dimensional space, one also needs an orientation: they need to be compared to a frame of reference.",
"title": "Geometry: position vs. displacement"
},
{
"paragraph_id": 107,
"text": "This leads to the extensions discussed below, namely Huntley's directed dimensions and Siano's orientational analysis.",
"title": "Geometry: position vs. displacement"
},
{
"paragraph_id": 108,
"text": "Huntley has pointed out that a dimensional analysis can become more powerful by discovering new independent dimensions in the quantities under consideration, thus increasing the rank m {\\displaystyle m} of the dimensional matrix.",
"title": "Geometry: position vs. displacement"
},
{
"paragraph_id": 109,
"text": "He introduced two approaches:",
"title": "Geometry: position vs. displacement"
},
{
"paragraph_id": 110,
"text": "As an example of the usefulness of the first approach, suppose we wish to calculate the distance a cannonball travels when fired with a vertical velocity component V y {\\displaystyle V_{\\mathrm {y} }} and a horizontal velocity component V x {\\displaystyle V_{\\mathrm {x} }} , assuming it is fired on a flat surface. Assuming no use of directed lengths, the quantities of interest are then R, the distance travelled, with dimension L, V x {\\displaystyle V_{\\mathrm {x} }} , V y {\\displaystyle V_{\\mathrm {y} }} , both dimensioned as TL, and g the downward acceleration of gravity, with dimension TL.",
"title": "Geometry: position vs. displacement"
},
{
"paragraph_id": 111,
"text": "With these four quantities, we may conclude that the equation for the range R may be written:",
"title": "Geometry: position vs. displacement"
},
{
"paragraph_id": 112,
"text": "Or dimensionally",
"title": "Geometry: position vs. displacement"
},
{
"paragraph_id": 113,
"text": "from which we may deduce that a + b + c = 1 {\\displaystyle a+b+c=1} and a + b + 2 c = 0 {\\displaystyle a+b+2c=0} , which leaves one exponent undetermined. This is to be expected since we have two fundamental dimensions T and L, and four parameters, with one equation.",
"title": "Geometry: position vs. displacement"
},
{
"paragraph_id": 114,
"text": "However, if we use directed length dimensions, then V x {\\displaystyle V_{\\mathrm {x} }} will be dimensioned as TLx, V y {\\displaystyle V_{\\mathrm {y} }} as TLy, R as Lx and g as TLy. The dimensional equation becomes:",
"title": "Geometry: position vs. displacement"
},
{
"paragraph_id": 115,
"text": "and we may solve completely as a = 1 {\\displaystyle a=1} , b = 1 {\\displaystyle b=1} and c = − 1 {\\displaystyle c=-1} . The increase in deductive power gained by the use of directed length dimensions is apparent.",
"title": "Geometry: position vs. displacement"
},
{
"paragraph_id": 116,
"text": "Huntley's concept of directed length dimensions however has some serious limitations:",
"title": "Geometry: position vs. displacement"
},
{
"paragraph_id": 117,
"text": "It also is often quite difficult to assign the L, Lx, Ly, Lz, symbols to the physical variables involved in the problem of interest. He invokes a procedure that involves the \"symmetry\" of the physical problem. This is often very difficult to apply reliably: It is unclear as to what parts of the problem that the notion of \"symmetry\" is being invoked. Is it the symmetry of the physical body that forces are acting upon, or to the points, lines or areas at which forces are being applied? What if more than one body is involved with different symmetries?",
"title": "Geometry: position vs. displacement"
},
{
"paragraph_id": 118,
"text": "Consider the spherical bubble attached to a cylindrical tube, where one wants the flow rate of air as a function of the pressure difference in the two parts. What are the Huntley extended dimensions of the viscosity of the air contained in the connected parts? What are the extended dimensions of the pressure of the two parts? Are they the same or different? These difficulties are responsible for the limited application of Huntley's directed length dimensions to real problems.",
"title": "Geometry: position vs. displacement"
},
{
"paragraph_id": 119,
"text": "In Huntley's second approach, he holds that it is sometimes useful (e.g., in fluid mechanics and thermodynamics) to distinguish between mass as a measure of inertia (inertial mass), and mass as a measure of the quantity of matter. Quantity of matter is defined by Huntley as a quantity only proportional to inertial mass, while not implicating inertial properties. No further restrictions are added to its definition.",
"title": "Geometry: position vs. displacement"
},
{
"paragraph_id": 120,
"text": "For example, consider the derivation of Poiseuille's Law. We wish to find the rate of mass flow of a viscous fluid through a circular pipe. Without drawing distinctions between inertial and substantial mass, we may choose as the relevant variables:",
"title": "Geometry: position vs. displacement"
},
{
"paragraph_id": 121,
"text": "There are three fundamental variables, so the above five equations will yield two independent dimensionless variables:",
"title": "Geometry: position vs. displacement"
},
{
"paragraph_id": 122,
"text": "If we distinguish between inertial mass with dimension M i {\\displaystyle M_{\\text{i}}} and quantity of matter with dimension M m {\\displaystyle M_{\\text{m}}} , then mass flow rate and density will use quantity of matter as the mass parameter, while the pressure gradient and coefficient of viscosity will use inertial mass. We now have four fundamental parameters, and one dimensionless constant, so that the dimensional equation may be written:",
"title": "Geometry: position vs. displacement"
},
{
"paragraph_id": 123,
"text": "where now only C is an undetermined constant (found to be equal to π / 8 {\\displaystyle \\pi /8} by methods outside of dimensional analysis). This equation may be solved for the mass flow rate to yield Poiseuille's law.",
"title": "Geometry: position vs. displacement"
},
{
"paragraph_id": 124,
"text": "Huntley's recognition of quantity of matter as an independent quantity dimension is evidently successful in the problems where it is applicable, but his definition of quantity of matter is open to interpretation, as it lacks specificity beyond the two requirements he postulated for it. For a given substance, the SI dimension amount of substance, with unit mole, does satisfy Huntley's two requirements as a measure of quantity of matter, and could be used as a quantity of matter in any problem of dimensional analysis where Huntley's concept is applicable.",
"title": "Geometry: position vs. displacement"
},
{
"paragraph_id": 125,
"text": "Angles are, by convention, considered to be dimensionless quantities. As an example, consider again the projectile problem in which a point mass is launched from the origin (x, y) = (0, 0) at a speed v and angle θ above the x-axis, with the force of gravity directed along the negative y-axis. It is desired to find the range R, at which point the mass returns to the x-axis. Conventional analysis will yield the dimensionless variable π = R g/v, but offers no insight into the relationship between R and θ.",
"title": "Geometry: position vs. displacement"
},
{
"paragraph_id": 126,
"text": "Siano has suggested that the directed dimensions of Huntley be replaced by using orientational symbols 1x 1y 1z to denote vector directions, and an orientationless symbol 10. Thus, Huntley's Lx becomes L1x with L specifying the dimension of length, and 1x specifying the orientation. Siano further shows that the orientational symbols have an algebra of their own. Along with the requirement that 1i = 1i, the following multiplication table for the orientation symbols results:",
"title": "Geometry: position vs. displacement"
},
{
"paragraph_id": 127,
"text": "The orientational symbols form a group (the Klein four-group or \"Viergruppe\"). In this system, scalars always have the same orientation as the identity element, independent of the \"symmetry of the problem\". Physical quantities that are vectors have the orientation expected: a force or a velocity in the z-direction has the orientation of 1z. For angles, consider an angle θ that lies in the z-plane. Form a right triangle in the z-plane with θ being one of the acute angles. The side of the right triangle adjacent to the angle then has an orientation 1x and the side opposite has an orientation 1y. Since (using ~ to indicate orientational equivalence) tan(θ) = θ + ... ~ 1y/1x we conclude that an angle in the xy-plane must have an orientation 1y/1x = 1z, which is not unreasonable. Analogous reasoning forces the conclusion that sin(θ) has orientation 1z while cos(θ) has orientation 10. These are different, so one concludes (correctly), for example, that there are no solutions of physical equations that are of the form a cos(θ) + b sin(θ), where a and b are real scalars. An expression such as sin ( θ + π / 2 ) = cos ( θ ) {\\displaystyle \\sin(\\theta +\\pi /2)=\\cos(\\theta )} is not dimensionally inconsistent since it is a special case of the sum of angles formula and should properly be written:",
"title": "Geometry: position vs. displacement"
},
{
"paragraph_id": 128,
"text": "which for a = θ {\\displaystyle a=\\theta } and b = π / 2 {\\displaystyle b=\\pi /2} yields sin ( θ 1 z + [ π / 2 ] 1 z ) = 1 z cos ( θ 1 z ) {\\displaystyle \\sin(\\theta \\,1_{\\text{z}}+[\\pi /2]\\,1_{\\text{z}})=1_{\\text{z}}\\cos(\\theta \\,1_{\\text{z}})} . Siano distinguishes between geometric angles, which have an orientation in 3-dimensional space, and phase angles associated with time-based oscillations, which have no spatial orientation, i.e. the orientation of a phase angle is 1 0 {\\displaystyle 1_{0}} .",
"title": "Geometry: position vs. displacement"
},
{
"paragraph_id": 129,
"text": "The assignment of orientational symbols to physical quantities and the requirement that physical equations be orientationally homogeneous can actually be used in a way that is similar to dimensional analysis to derive more information about acceptable solutions of physical problems. In this approach, one solves the dimensional equation as far as one can. If the lowest power of a physical variable is fractional, both sides of the solution is raised to a power such that all powers are integral, putting it into normal form. The orientational equation is then solved to give a more restrictive condition on the unknown powers of the orientational symbols. The solution is then more complete than the one that dimensional analysis alone gives. Often, the added information is that one of the powers of a certain variable is even or odd.",
"title": "Geometry: position vs. displacement"
},
{
"paragraph_id": 130,
"text": "As an example, for the projectile problem, using orientational symbols, θ, being in the xy-plane will thus have dimension 1z and the range of the projectile R will be of the form:",
"title": "Geometry: position vs. displacement"
},
{
"paragraph_id": 131,
"text": "Dimensional homogeneity will now correctly yield a = −1 and b = 2, and orientational homogeneity requires that 1 x / ( 1 y a 1 z c ) = 1 z c + 1 = 1 {\\displaystyle 1_{x}/(1_{y}^{a}1_{z}^{c})=1_{z}^{c+1}=1} . In other words, that c must be an odd integer. In fact, the required function of theta will be sin(θ)cos(θ) which is a series consisting of odd powers of θ.",
"title": "Geometry: position vs. displacement"
},
{
"paragraph_id": 132,
"text": "It is seen that the Taylor series of sin(θ) and cos(θ) are orientationally homogeneous using the above multiplication table, while expressions like cos(θ) + sin(θ) and exp(θ) are not, and are (correctly) deemed unphysical.",
"title": "Geometry: position vs. displacement"
},
{
"paragraph_id": 133,
"text": "Siano's orientational analysis is compatible with the conventional conception of angular quantities as being dimensionless, and within orientational analysis, the radian may still be considered a dimensionless unit. The orientational analysis of a quantity equation is carried out separately from the ordinary dimensional analysis, yielding information that supplements the dimensional analysis.",
"title": "Geometry: position vs. displacement"
}
] | In engineering and science, dimensional analysis is the analysis of the relationships between different physical quantities by identifying their base quantities and units of measurement and tracking these dimensions as calculations or comparisons are performed. The term dimensional analysis is also used to refer to conversion of units from one dimensional unit to another, which can be used to evaluate scientific formulae. Commensurable physical quantities are of the same kind and have the same dimension, and can be directly compared to each other, even if they are expressed in differing units of measurement; e.g., metres and feet, grams and pounds, seconds and years. Incommensurable physical quantities are of different kinds and have different dimensions, and can not be directly compared to each other, no matter what units they are expressed in, e.g. metres and grams, seconds and grams, metres and seconds. For example, asking whether a gram is larger than an hour is meaningless. Any physically meaningful equation, or inequality, must have the same dimensions on its left and right sides, a property known as dimensional homogeneity. Checking for dimensional homogeneity is a common application of dimensional analysis, serving as a plausibility check on derived equations and computations. It also serves as a guide and constraint in deriving equations that may describe a physical system in the absence of a more rigorous derivation. The concept of physical dimension, and of dimensional analysis, was introduced by Joseph Fourier in 1822. | 2001-11-04T03:00:52Z | 2023-12-31T19:59:26Z | [
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8,270 | December 25 | December 25 is the 359th day of the year (360th in leap years) in the Gregorian calendar; six days remain until the end of the year. | [
{
"paragraph_id": 0,
"text": "December 25 is the 359th day of the year (360th in leap years) in the Gregorian calendar; six days remain until the end of the year.",
"title": ""
}
] | December 25 is the 359th day of the year in the Gregorian calendar; six days remain until the end of the year. | 2001-10-26T23:21:50Z | 2023-12-29T19:03:39Z | [
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8,271 | Digital television | Digital television (DTV) is the transmission of television signals using digital encoding, in contrast to the earlier analog television technology which used analog signals. At the time of its development it was considered an innovative advancement and represented the first significant evolution in television technology since color television in the 1950s. Modern digital television is transmitted in high-definition television (HDTV) with greater resolution than analog TV. It typically uses a widescreen aspect ratio (commonly 16:9) in contrast to the narrower format (4:3) of analog TV. It makes more economical use of scarce radio spectrum space; it can transmit up to seven channels in the same bandwidth as a single analog channel, and provides many new features that analog television cannot. A transition from analog to digital broadcasting began around 2000. Different digital television broadcasting standards have been adopted in different parts of the world; below are the more widely used standards:
Digital television's roots are tied to the availability of inexpensive, high performance computers. It was not until the 1990s that digital TV became a real possibility. Digital television was previously not practically feasible due to the impractically high bandwidth requirements of uncompressed video, requiring around 200 Mbit/s for a standard-definition television (SDTV) signal, and over 1 Gbit/s for high-definition television (HDTV).
In the mid-1980s, Toshiba released a television set with digital capabilities, using integrated circuit chips such as a microprocessor to convert analog television broadcast signals to digital video signals, enabling features such as freezing pictures and showing two channels at once. In 1986, Sony and NEC Home Electronics announced their own similar TV sets with digital video capabilities. However, they still relied on analog TV broadcast signals, with true digital TV broadcasts not yet being available at the time.
A digital TV broadcast service was proposed in 1986 by Nippon Telegraph and Telephone (NTT) and the Ministry of Posts and Telecommunication (MPT) in Japan, where there were plans to develop an "Integrated Network System" service. However, it was not possible to practically implement such a digital TV service until the adoption of motion-compensated DCT video compression formats such as MPEG made it possible in the early 1990s.
In the mid-1980s, as Japanese consumer electronics firms forged ahead with the development of HDTV technology, and as the MUSE analog format was proposed by Japan's public broadcaster NHK as a worldwide standard. Japanese advancements were seen as pacesetters that threatened to eclipse US electronics companies. Until June 1990, the Japanese MUSE standard—based on an analog system—was the front-runner among the more than 23 different technical concepts under consideration.
Between 1988 and 1991, several European organizations were working on DCT-based digital video coding standards for both SDTV and HDTV. The EU 256 project by the CMTT and ETSI, along with research by Italian broadcaster RAI, developed a DCT video codec that broadcast SDTV at 34 Mbit/s and near-studio-quality HDTV at about 70–140 Mbit/s. RAI demonstrated this with a 1990 FIFA World Cup broadcast in March 1990. An American company, General Instrument, also demonstrated the feasibility of a digital television signal in 1990. This led to the FCC being persuaded to delay its decision on an advanced television (ATV) standard until a digitally based standard could be developed.
In March 1990, when it became clear that a digital standard was feasible, the FCC made a number of critical decisions. First, the Commission declared that the new TV standard must be more than an enhanced analog signal, but be able to provide a genuine HDTV signal with at least twice the resolution of existing television images. Then, to ensure that viewers who did not wish to buy a new digital television set could continue to receive conventional television broadcasts, it dictated that the new ATV standard must be capable of being simulcast on different channels. The new ATV standard also allowed the new DTV signal to be based on entirely new design principles. Although incompatible with the existing NTSC standard, the new DTV standard would be able to incorporate many improvements.
The final standard adopted by the FCC did not produce a universal standard for scanning formats, aspect ratios, or lines of resolution. This outcome resulted from a dispute between the consumer electronics industry (joined by some broadcasters) and the computer industry (joined by the film industry and some public interest groups) over which of the two scanning processes—interlaced or progressive—is superior. Interlaced scanning, which is used in televisions worldwide, scans even-numbered lines first, then odd-numbered ones. Progressive scanning, which is the format used in computers, scans lines in sequences, from top to bottom. The computer industry argued that progressive scanning is superior because it does not flicker in the manner of interlaced scanning. It also argued that progressive scanning enables easier connections with the Internet, and is more cheaply converted to interlaced formats than vice versa. The film industry also supported progressive scanning because it offers a more efficient means of converting filmed programming into digital formats. For their part, the consumer electronics industry and broadcasters argued that interlaced scanning was the only technology that could transmit the highest quality pictures then (and currently) feasible, i.e., 1,080 lines per picture and 1,920 pixels per line. Broadcasters also favored interlaced scanning because their vast archive of interlaced programming is not readily compatible with a progressive format.
DirecTV in the US launched the first commercial digital satellite platform in May 1994, using the Digital Satellite System (DSS) standard. Digital cable broadcasts were tested and launched in the US in 1996 by TCI and Time Warner. The first digital terrestrial platform was launched in November 1998 as ONdigital in the UK, using the DVB-T standard.
Digital television supports many different picture formats defined by the broadcast television systems which are a combination of size and aspect ratio (width to height ratio).
With digital terrestrial television (DTT) broadcasting, the range of formats can be broadly divided into two categories: high-definition television (HDTV) for the transmission of high-definition video and standard-definition television (SDTV). These terms by themselves are not very precise, and many subtle intermediate cases exist.
One of several different HDTV formats that can be transmitted over DTV is: 1280 × 720 pixels in progressive scan mode (abbreviated 720p) or 1920 × 1080 pixels in interlaced video mode (1080i). Each of these uses a 16:9 aspect ratio. HDTV cannot be transmitted over analog television channels because of channel capacity issues.
SDTV, by comparison, may use one of several different formats taking the form of various aspect ratios depending on the technology used in the country of broadcast. NTSC can deliver a 640 × 480 resolution in 4:3 and 854 × 480 in 16:9, while PAL can give 768 × 576 in 4:3 and 1024 × 576 in 16:9. However, broadcasters may choose to reduce these resolutions to reduce bit rate (e.g., many DVB-T channels in the UK use a horizontal resolution of 544 or 704 pixels per line).
Each commercial broadcasting terrestrial television DTV channel in North America is allocated enough bandwidth to broadcast up to 19 megabits per second. However, the broadcaster does not need to use this entire bandwidth for just one broadcast channel. Instead, the broadcast can use Program and System Information Protocol and subdivide across several video subchannels (a.k.a. feeds) of varying quality and compression rates, including non-video datacasting services.
A broadcaster may opt to use a standard-definition (SDTV) digital signal instead of an HDTV signal, because current convention allows the bandwidth of a DTV channel (or "multiplex") to be subdivided into multiple digital subchannels, (similar to what most FM radio stations offer with HD Radio), providing multiple feeds of entirely different television programming on the same channel. This ability to provide either a single HDTV feed or multiple lower-resolution feeds is often referred to as distributing one's bit budget or multicasting. This can sometimes be arranged automatically, using a statistical multiplexer. With some implementations, image resolution may be less directly limited by bandwidth; for example in DVB-T, broadcasters can choose from several different modulation schemes, giving them the option to reduce the transmission bit rate and make reception easier for more distant or mobile viewers.
There are several different ways to receive digital television. One of the oldest means of receiving DTV (and TV in general) is from terrestrial transmitters using an antenna (known as an aerial in some countries). This delivery method is known as digital terrestrial television (DTT). With DTT, viewers are limited to channels that have a terrestrial transmitter in range of their antenna.
Other delivery methods include digital cable and digital satellite. In some countries where transmissions of TV signals are normally achieved by microwaves, digital multichannel multipoint distribution service is used. Other standards, such as digital multimedia broadcasting (DMB) and digital video broadcasting - handheld (DVB-H), have been devised to allow handheld devices such as mobile phones to receive TV signals. Another way is Internet Protocol television (IPTV), which is the delivery of TV over a computer network. Finally, an alternative way is to receive digital TV signals via the open Internet (Internet television), whether from a central streaming service or a P2P (peer-to-peer) system.
Some signals are protected by encryption and backed up with the force of law under the WIPO Copyright Treaty and national legislation implementing it, such as the US Digital Millennium Copyright Act. Access to encrypted channels can be controlled by a removable card, for example via the Common Interface or CableCard.
Digital television signals must not interfere with each other, and they must also coexist with analog television until it is phased out. The following table gives allowable signal-to-noise and signal-to-interference ratios for various interference scenarios. This table is a crucial regulatory tool for controlling the placement and power levels of stations. Digital TV is more tolerant of interference than analog TV.
People can interact with a DTV system in various ways. One can, for example, browse the electronic program guide. Modern DTV systems sometimes use a return path providing feedback from the end user to the broadcaster. This is possible over cable TV or through an Internet connection but is not possible with a standard antenna alone.
Some of these systems support video on demand using a communication channel localized to a neighborhood rather than a city (terrestrial) or an even larger area (satellite).
1seg (1-segment) is a special form of ISDB. Each channel is further divided into 13 segments. Twelve are allocated for HDTV and the other for narrow-band receivers such as mobile televisions and cell phones.
DTV has several advantages over analog television, the most significant being that digital channels take up less bandwidth, and the bandwidth allocations are flexible depending on the level of compression and resolution of the transmitted image. This means that digital broadcasters can provide more digital channels in the same space, provide high-definition television service, or provide other non-television services such as multimedia or interactivity. DTV also permits special services such as multiplexing (more than one program on the same channel), electronic program guides and additional languages (spoken or subtitled). The sale of non-television services may provide an additional revenue source to broadcasters.
Digital and analog signals react to interference differently. For example, common problems with analog television include ghosting of images, noise from weak signals, and other problems that degrade the quality of the image and sound, although the program material may still be watchable. With digital television, because of the cliff effect, reception of the digital signal must be very nearly complete; otherwise, neither audio nor video will be usable.
Analog TV began with monophonic sound and later developed multichannel television sound with two independent audio signal channels. DTV allows up to 5 audio signal channels plus a subwoofer bass channel, producing broadcasts similar in quality to movie theaters and DVDs.
Digital TV signals require less transmission power than analog TV signals to be broadcast and received satisfactorily.
DTV images have some picture defects that are not present on analog television or motion picture cinema, because of present-day limitations of bit rate and compression algorithms such as MPEG-2. This defect is sometimes referred to as mosquito noise.
Because of the way the human visual system works, defects in an image that are localized to particular features of the image or that come and go are more perceptible than defects that are uniform and constant. However, the DTV system is designed to take advantage of other limitations of the human visual system to help mask these flaws, e.g. by allowing more compression artifacts during fast motion where the eye cannot track and resolve them as easily and, conversely, minimizing artifacts in still backgrounds that, because time allows, may be closely examined in a scene.
Broadcast, cable, satellite, and Internet DTV operators control the picture quality of television signal encoders using sophisticated, neuroscience-based algorithms, such as the structural similarity index measure (SSIM) video quality measurement tool. Another tool called visual information fidelity (VIF), is used in the Netflix VMAF video quality monitoring system.
Changes in signal reception from factors such as degrading antenna connections or changing weather conditions may gradually reduce the quality of analog TV. The nature of digital TV results in a perfectly decodable video initially, until the receiving equipment starts picking up interference that overpowers the desired signal or if the signal is too weak to decode. Some equipment will show a garbled picture with significant damage, while other devices may go directly from perfectly decodable video to no video at all or lock up. This phenomenon is known as the digital cliff effect.
Block errors may occur when transmission is done with compressed images. A block error in a single frame often results in black boxes in several subsequent frames, making viewing difficult.
For remote locations, distant channels that, as analog signals, were previously usable in a snowy and degraded state may, as digital signals, be perfectly decodable or may become completely unavailable. The use of higher frequencies add to these problems, especially in cases where a clear line-of-sight from the receiving antenna to the transmitter is not available, because usually higher frequency signals can't pass through obstacles as easily.
Television sets with only analog tuners cannot decode digital transmissions. When analog broadcasting over the air ceases, users of sets with analog-only tuners may use other sources of programming (e.g. cable, recorded media) or may purchase set-top converter boxes to tune in the digital signals. In the United States, a government-sponsored coupon was available to offset the cost of an external converter box. Analog switch-off (of full-power stations) took place on December 11, 2006, in The Netherlands, June 12, 2009 in the United States for full-power stations, and later for Class-A Stations on September 1, 2016, July 24, 2011 in Japan, August 31, 2011 in Canada, February 13, 2012 in Arab states, May 1, 2012, in Germany, October 24, 2012, in the United Kingdom and Ireland, October 31, 2012 in selected Indian cities, and December 10, 2013, in Australia. Completion of analog switch-off is scheduled for December 31, 2017 in the whole of India, December 2018 in Costa Rica and around 2023 for the Philippines.
Prior to the conversion to digital TV, analog television broadcast audio for TV channels on a separate FM carrier signal from the video signal. This FM audio signal could be heard using standard radios equipped with the appropriate tuning circuits.
However, after the digital television transition, no portable radio manufacturer has yet developed an alternative method for portable radios to play just the audio signal of digital TV channels; DTV radio is not the same thing.
The adoption of a broadcast standard incompatible with existing analog receivers has created the problem of large numbers of analog receivers being discarded during digital television transition. One superintendent of public works was quoted in 2009 saying; "some of the studies I’ve read in the trade magazines say up to a quarter of American households could be throwing a TV out in the next two years following the regulation change". In 2009, an estimated 99 million analog TV receivers were sitting unused in homes in the US alone and, while some obsolete receivers are being retrofitted with converters, many more are simply dumped in landfills where they represent a source of toxic metals such as lead as well as lesser amounts of materials such as barium, cadmium and chromium.
According to one campaign group, a CRT computer monitor or TV contains an average of 8 pounds (3.6 kg) of lead. According to another source, the lead in glass of a CRT varies from 1.08 lb to 11.28 lb, depending on screen size and type, but the lead is in the form of "stable and immobile" lead oxide mixed into the glass. It is claimed that the lead can have long-term negative effects on the environment if dumped as landfill. However, the glass envelope can be recycled at suitably equipped facilities. Other portions of the receiver may be subject to disposal as hazardous material.
Local restrictions on disposal of these materials vary widely; in some cases second-hand stores have refused to accept working color television receivers for resale due to the increasing costs of disposing of unsold TVs. Those thrift stores which are still accepting donated TVs have reported significant increases in good-condition working used television receivers abandoned by viewers who often expect them not to work after digital transition.
In Michigan in 2009, one recycler estimated that as many as one household in four would dispose of or recycle a TV set in the following year. The digital television transition, migration to high-definition television receivers and the replacement of CRTs with flatscreens are all factors in the increasing number of discarded analog CRT-based television receivers. | [
{
"paragraph_id": 0,
"text": "Digital television (DTV) is the transmission of television signals using digital encoding, in contrast to the earlier analog television technology which used analog signals. At the time of its development it was considered an innovative advancement and represented the first significant evolution in television technology since color television in the 1950s. Modern digital television is transmitted in high-definition television (HDTV) with greater resolution than analog TV. It typically uses a widescreen aspect ratio (commonly 16:9) in contrast to the narrower format (4:3) of analog TV. It makes more economical use of scarce radio spectrum space; it can transmit up to seven channels in the same bandwidth as a single analog channel, and provides many new features that analog television cannot. A transition from analog to digital broadcasting began around 2000. Different digital television broadcasting standards have been adopted in different parts of the world; below are the more widely used standards:",
"title": ""
},
{
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"text": "Digital television's roots are tied to the availability of inexpensive, high performance computers. It was not until the 1990s that digital TV became a real possibility. Digital television was previously not practically feasible due to the impractically high bandwidth requirements of uncompressed video, requiring around 200 Mbit/s for a standard-definition television (SDTV) signal, and over 1 Gbit/s for high-definition television (HDTV).",
"title": "History"
},
{
"paragraph_id": 2,
"text": "In the mid-1980s, Toshiba released a television set with digital capabilities, using integrated circuit chips such as a microprocessor to convert analog television broadcast signals to digital video signals, enabling features such as freezing pictures and showing two channels at once. In 1986, Sony and NEC Home Electronics announced their own similar TV sets with digital video capabilities. However, they still relied on analog TV broadcast signals, with true digital TV broadcasts not yet being available at the time.",
"title": "History"
},
{
"paragraph_id": 3,
"text": "A digital TV broadcast service was proposed in 1986 by Nippon Telegraph and Telephone (NTT) and the Ministry of Posts and Telecommunication (MPT) in Japan, where there were plans to develop an \"Integrated Network System\" service. However, it was not possible to practically implement such a digital TV service until the adoption of motion-compensated DCT video compression formats such as MPEG made it possible in the early 1990s.",
"title": "History"
},
{
"paragraph_id": 4,
"text": "In the mid-1980s, as Japanese consumer electronics firms forged ahead with the development of HDTV technology, and as the MUSE analog format was proposed by Japan's public broadcaster NHK as a worldwide standard. Japanese advancements were seen as pacesetters that threatened to eclipse US electronics companies. Until June 1990, the Japanese MUSE standard—based on an analog system—was the front-runner among the more than 23 different technical concepts under consideration.",
"title": "History"
},
{
"paragraph_id": 5,
"text": "Between 1988 and 1991, several European organizations were working on DCT-based digital video coding standards for both SDTV and HDTV. The EU 256 project by the CMTT and ETSI, along with research by Italian broadcaster RAI, developed a DCT video codec that broadcast SDTV at 34 Mbit/s and near-studio-quality HDTV at about 70–140 Mbit/s. RAI demonstrated this with a 1990 FIFA World Cup broadcast in March 1990. An American company, General Instrument, also demonstrated the feasibility of a digital television signal in 1990. This led to the FCC being persuaded to delay its decision on an advanced television (ATV) standard until a digitally based standard could be developed.",
"title": "History"
},
{
"paragraph_id": 6,
"text": "In March 1990, when it became clear that a digital standard was feasible, the FCC made a number of critical decisions. First, the Commission declared that the new TV standard must be more than an enhanced analog signal, but be able to provide a genuine HDTV signal with at least twice the resolution of existing television images. Then, to ensure that viewers who did not wish to buy a new digital television set could continue to receive conventional television broadcasts, it dictated that the new ATV standard must be capable of being simulcast on different channels. The new ATV standard also allowed the new DTV signal to be based on entirely new design principles. Although incompatible with the existing NTSC standard, the new DTV standard would be able to incorporate many improvements.",
"title": "History"
},
{
"paragraph_id": 7,
"text": "The final standard adopted by the FCC did not produce a universal standard for scanning formats, aspect ratios, or lines of resolution. This outcome resulted from a dispute between the consumer electronics industry (joined by some broadcasters) and the computer industry (joined by the film industry and some public interest groups) over which of the two scanning processes—interlaced or progressive—is superior. Interlaced scanning, which is used in televisions worldwide, scans even-numbered lines first, then odd-numbered ones. Progressive scanning, which is the format used in computers, scans lines in sequences, from top to bottom. The computer industry argued that progressive scanning is superior because it does not flicker in the manner of interlaced scanning. It also argued that progressive scanning enables easier connections with the Internet, and is more cheaply converted to interlaced formats than vice versa. The film industry also supported progressive scanning because it offers a more efficient means of converting filmed programming into digital formats. For their part, the consumer electronics industry and broadcasters argued that interlaced scanning was the only technology that could transmit the highest quality pictures then (and currently) feasible, i.e., 1,080 lines per picture and 1,920 pixels per line. Broadcasters also favored interlaced scanning because their vast archive of interlaced programming is not readily compatible with a progressive format.",
"title": "History"
},
{
"paragraph_id": 8,
"text": "DirecTV in the US launched the first commercial digital satellite platform in May 1994, using the Digital Satellite System (DSS) standard. Digital cable broadcasts were tested and launched in the US in 1996 by TCI and Time Warner. The first digital terrestrial platform was launched in November 1998 as ONdigital in the UK, using the DVB-T standard.",
"title": "History"
},
{
"paragraph_id": 9,
"text": "Digital television supports many different picture formats defined by the broadcast television systems which are a combination of size and aspect ratio (width to height ratio).",
"title": "Technical information"
},
{
"paragraph_id": 10,
"text": "With digital terrestrial television (DTT) broadcasting, the range of formats can be broadly divided into two categories: high-definition television (HDTV) for the transmission of high-definition video and standard-definition television (SDTV). These terms by themselves are not very precise, and many subtle intermediate cases exist.",
"title": "Technical information"
},
{
"paragraph_id": 11,
"text": "One of several different HDTV formats that can be transmitted over DTV is: 1280 × 720 pixels in progressive scan mode (abbreviated 720p) or 1920 × 1080 pixels in interlaced video mode (1080i). Each of these uses a 16:9 aspect ratio. HDTV cannot be transmitted over analog television channels because of channel capacity issues.",
"title": "Technical information"
},
{
"paragraph_id": 12,
"text": "SDTV, by comparison, may use one of several different formats taking the form of various aspect ratios depending on the technology used in the country of broadcast. NTSC can deliver a 640 × 480 resolution in 4:3 and 854 × 480 in 16:9, while PAL can give 768 × 576 in 4:3 and 1024 × 576 in 16:9. However, broadcasters may choose to reduce these resolutions to reduce bit rate (e.g., many DVB-T channels in the UK use a horizontal resolution of 544 or 704 pixels per line).",
"title": "Technical information"
},
{
"paragraph_id": 13,
"text": "Each commercial broadcasting terrestrial television DTV channel in North America is allocated enough bandwidth to broadcast up to 19 megabits per second. However, the broadcaster does not need to use this entire bandwidth for just one broadcast channel. Instead, the broadcast can use Program and System Information Protocol and subdivide across several video subchannels (a.k.a. feeds) of varying quality and compression rates, including non-video datacasting services.",
"title": "Technical information"
},
{
"paragraph_id": 14,
"text": "A broadcaster may opt to use a standard-definition (SDTV) digital signal instead of an HDTV signal, because current convention allows the bandwidth of a DTV channel (or \"multiplex\") to be subdivided into multiple digital subchannels, (similar to what most FM radio stations offer with HD Radio), providing multiple feeds of entirely different television programming on the same channel. This ability to provide either a single HDTV feed or multiple lower-resolution feeds is often referred to as distributing one's bit budget or multicasting. This can sometimes be arranged automatically, using a statistical multiplexer. With some implementations, image resolution may be less directly limited by bandwidth; for example in DVB-T, broadcasters can choose from several different modulation schemes, giving them the option to reduce the transmission bit rate and make reception easier for more distant or mobile viewers.",
"title": "Technical information"
},
{
"paragraph_id": 15,
"text": "There are several different ways to receive digital television. One of the oldest means of receiving DTV (and TV in general) is from terrestrial transmitters using an antenna (known as an aerial in some countries). This delivery method is known as digital terrestrial television (DTT). With DTT, viewers are limited to channels that have a terrestrial transmitter in range of their antenna.",
"title": "Technical information"
},
{
"paragraph_id": 16,
"text": "Other delivery methods include digital cable and digital satellite. In some countries where transmissions of TV signals are normally achieved by microwaves, digital multichannel multipoint distribution service is used. Other standards, such as digital multimedia broadcasting (DMB) and digital video broadcasting - handheld (DVB-H), have been devised to allow handheld devices such as mobile phones to receive TV signals. Another way is Internet Protocol television (IPTV), which is the delivery of TV over a computer network. Finally, an alternative way is to receive digital TV signals via the open Internet (Internet television), whether from a central streaming service or a P2P (peer-to-peer) system.",
"title": "Technical information"
},
{
"paragraph_id": 17,
"text": "Some signals are protected by encryption and backed up with the force of law under the WIPO Copyright Treaty and national legislation implementing it, such as the US Digital Millennium Copyright Act. Access to encrypted channels can be controlled by a removable card, for example via the Common Interface or CableCard.",
"title": "Technical information"
},
{
"paragraph_id": 18,
"text": "Digital television signals must not interfere with each other, and they must also coexist with analog television until it is phased out. The following table gives allowable signal-to-noise and signal-to-interference ratios for various interference scenarios. This table is a crucial regulatory tool for controlling the placement and power levels of stations. Digital TV is more tolerant of interference than analog TV.",
"title": "Technical information"
},
{
"paragraph_id": 19,
"text": "People can interact with a DTV system in various ways. One can, for example, browse the electronic program guide. Modern DTV systems sometimes use a return path providing feedback from the end user to the broadcaster. This is possible over cable TV or through an Internet connection but is not possible with a standard antenna alone.",
"title": "Technical information"
},
{
"paragraph_id": 20,
"text": "Some of these systems support video on demand using a communication channel localized to a neighborhood rather than a city (terrestrial) or an even larger area (satellite).",
"title": "Technical information"
},
{
"paragraph_id": 21,
"text": "1seg (1-segment) is a special form of ISDB. Each channel is further divided into 13 segments. Twelve are allocated for HDTV and the other for narrow-band receivers such as mobile televisions and cell phones.",
"title": "Technical information"
},
{
"paragraph_id": 22,
"text": "DTV has several advantages over analog television, the most significant being that digital channels take up less bandwidth, and the bandwidth allocations are flexible depending on the level of compression and resolution of the transmitted image. This means that digital broadcasters can provide more digital channels in the same space, provide high-definition television service, or provide other non-television services such as multimedia or interactivity. DTV also permits special services such as multiplexing (more than one program on the same channel), electronic program guides and additional languages (spoken or subtitled). The sale of non-television services may provide an additional revenue source to broadcasters.",
"title": "Comparison to analog"
},
{
"paragraph_id": 23,
"text": "Digital and analog signals react to interference differently. For example, common problems with analog television include ghosting of images, noise from weak signals, and other problems that degrade the quality of the image and sound, although the program material may still be watchable. With digital television, because of the cliff effect, reception of the digital signal must be very nearly complete; otherwise, neither audio nor video will be usable.",
"title": "Comparison to analog"
},
{
"paragraph_id": 24,
"text": "Analog TV began with monophonic sound and later developed multichannel television sound with two independent audio signal channels. DTV allows up to 5 audio signal channels plus a subwoofer bass channel, producing broadcasts similar in quality to movie theaters and DVDs.",
"title": "Comparison to analog"
},
{
"paragraph_id": 25,
"text": "Digital TV signals require less transmission power than analog TV signals to be broadcast and received satisfactorily.",
"title": "Comparison to analog"
},
{
"paragraph_id": 26,
"text": "DTV images have some picture defects that are not present on analog television or motion picture cinema, because of present-day limitations of bit rate and compression algorithms such as MPEG-2. This defect is sometimes referred to as mosquito noise.",
"title": "Comparison to analog"
},
{
"paragraph_id": 27,
"text": "Because of the way the human visual system works, defects in an image that are localized to particular features of the image or that come and go are more perceptible than defects that are uniform and constant. However, the DTV system is designed to take advantage of other limitations of the human visual system to help mask these flaws, e.g. by allowing more compression artifacts during fast motion where the eye cannot track and resolve them as easily and, conversely, minimizing artifacts in still backgrounds that, because time allows, may be closely examined in a scene.",
"title": "Comparison to analog"
},
{
"paragraph_id": 28,
"text": "Broadcast, cable, satellite, and Internet DTV operators control the picture quality of television signal encoders using sophisticated, neuroscience-based algorithms, such as the structural similarity index measure (SSIM) video quality measurement tool. Another tool called visual information fidelity (VIF), is used in the Netflix VMAF video quality monitoring system.",
"title": "Comparison to analog"
},
{
"paragraph_id": 29,
"text": "Changes in signal reception from factors such as degrading antenna connections or changing weather conditions may gradually reduce the quality of analog TV. The nature of digital TV results in a perfectly decodable video initially, until the receiving equipment starts picking up interference that overpowers the desired signal or if the signal is too weak to decode. Some equipment will show a garbled picture with significant damage, while other devices may go directly from perfectly decodable video to no video at all or lock up. This phenomenon is known as the digital cliff effect.",
"title": "Comparison to analog"
},
{
"paragraph_id": 30,
"text": "Block errors may occur when transmission is done with compressed images. A block error in a single frame often results in black boxes in several subsequent frames, making viewing difficult.",
"title": "Comparison to analog"
},
{
"paragraph_id": 31,
"text": "For remote locations, distant channels that, as analog signals, were previously usable in a snowy and degraded state may, as digital signals, be perfectly decodable or may become completely unavailable. The use of higher frequencies add to these problems, especially in cases where a clear line-of-sight from the receiving antenna to the transmitter is not available, because usually higher frequency signals can't pass through obstacles as easily.",
"title": "Comparison to analog"
},
{
"paragraph_id": 32,
"text": "Television sets with only analog tuners cannot decode digital transmissions. When analog broadcasting over the air ceases, users of sets with analog-only tuners may use other sources of programming (e.g. cable, recorded media) or may purchase set-top converter boxes to tune in the digital signals. In the United States, a government-sponsored coupon was available to offset the cost of an external converter box. Analog switch-off (of full-power stations) took place on December 11, 2006, in The Netherlands, June 12, 2009 in the United States for full-power stations, and later for Class-A Stations on September 1, 2016, July 24, 2011 in Japan, August 31, 2011 in Canada, February 13, 2012 in Arab states, May 1, 2012, in Germany, October 24, 2012, in the United Kingdom and Ireland, October 31, 2012 in selected Indian cities, and December 10, 2013, in Australia. Completion of analog switch-off is scheduled for December 31, 2017 in the whole of India, December 2018 in Costa Rica and around 2023 for the Philippines.",
"title": "Comparison to analog"
},
{
"paragraph_id": 33,
"text": "Prior to the conversion to digital TV, analog television broadcast audio for TV channels on a separate FM carrier signal from the video signal. This FM audio signal could be heard using standard radios equipped with the appropriate tuning circuits.",
"title": "Comparison to analog"
},
{
"paragraph_id": 34,
"text": "However, after the digital television transition, no portable radio manufacturer has yet developed an alternative method for portable radios to play just the audio signal of digital TV channels; DTV radio is not the same thing.",
"title": "Comparison to analog"
},
{
"paragraph_id": 35,
"text": "The adoption of a broadcast standard incompatible with existing analog receivers has created the problem of large numbers of analog receivers being discarded during digital television transition. One superintendent of public works was quoted in 2009 saying; \"some of the studies I’ve read in the trade magazines say up to a quarter of American households could be throwing a TV out in the next two years following the regulation change\". In 2009, an estimated 99 million analog TV receivers were sitting unused in homes in the US alone and, while some obsolete receivers are being retrofitted with converters, many more are simply dumped in landfills where they represent a source of toxic metals such as lead as well as lesser amounts of materials such as barium, cadmium and chromium.",
"title": "Comparison to analog"
},
{
"paragraph_id": 36,
"text": "According to one campaign group, a CRT computer monitor or TV contains an average of 8 pounds (3.6 kg) of lead. According to another source, the lead in glass of a CRT varies from 1.08 lb to 11.28 lb, depending on screen size and type, but the lead is in the form of \"stable and immobile\" lead oxide mixed into the glass. It is claimed that the lead can have long-term negative effects on the environment if dumped as landfill. However, the glass envelope can be recycled at suitably equipped facilities. Other portions of the receiver may be subject to disposal as hazardous material.",
"title": "Comparison to analog"
},
{
"paragraph_id": 37,
"text": "Local restrictions on disposal of these materials vary widely; in some cases second-hand stores have refused to accept working color television receivers for resale due to the increasing costs of disposing of unsold TVs. Those thrift stores which are still accepting donated TVs have reported significant increases in good-condition working used television receivers abandoned by viewers who often expect them not to work after digital transition.",
"title": "Comparison to analog"
},
{
"paragraph_id": 38,
"text": "In Michigan in 2009, one recycler estimated that as many as one household in four would dispose of or recycle a TV set in the following year. The digital television transition, migration to high-definition television receivers and the replacement of CRTs with flatscreens are all factors in the increasing number of discarded analog CRT-based television receivers.",
"title": "Comparison to analog"
}
] | Digital television (DTV) is the transmission of television signals using digital encoding, in contrast to the earlier analog television technology which used analog signals. At the time of its development it was considered an innovative advancement and represented the first significant evolution in television technology since color television in the 1950s. Modern digital television is transmitted in high-definition television (HDTV) with greater resolution than analog TV. It typically uses a widescreen aspect ratio in contrast to the narrower format (4:3) of analog TV. It makes more economical use of scarce radio spectrum space; it can transmit up to seven channels in the same bandwidth as a single analog channel, and provides many new features that analog television cannot. A transition from analog to digital broadcasting began around 2000. Different digital television broadcasting standards have been adopted in different parts of the world; below are the more widely used standards: Digital Video Broadcasting (DVB) uses coded orthogonal frequency-division multiplexing (OFDM) modulation and supports hierarchical transmission. This standard has been adopted in Europe, Africa, Asia, and Australia, for a total of approximately 60 countries.
Advanced Television System Committee (ATSC) standard uses eight-level vestigial sideband (8VSB) for terrestrial broadcasting. This standard has been adopted by 9 countries: the United States, Canada, Mexico, South Korea, Bahamas, Jamaica, the Dominican Republic, Haiti and Suriname.
Integrated Services Digital Broadcasting (ISDB) is a system designed to provide good reception to fixed receivers and also portable or mobile receivers. It utilizes OFDM and two-dimensional interleaving. It supports hierarchical transmission of up to three layers and uses MPEG-2 video and Advanced Audio Coding. This standard has been adopted in Japan and the Philippines. ISDB-T International is an adaptation of this standard using H.264/MPEG-4 AVC, which has been adopted in most of South America and Portuguese-speaking African countries.
Digital Terrestrial Multimedia Broadcast (DTMB) adopts time-domain synchronous (TDS) OFDM technology with a pseudo-random signal frame to serve as the guard interval (GI) of the OFDM block and the training symbol. The DTMB standard has been adopted in China, including Hong Kong and Macau.
Digital Multimedia Broadcasting (DMB) is a digital radio transmission technology developed in South Korea as part of the national information technology project for sending multimedia such as TV, radio and datacasting to mobile devices such as mobile phones, laptops and GPS navigation systems. | 2001-10-31T00:10:41Z | 2023-12-02T00:35:20Z | [
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8,274 | Declaration of Arbroath | The Declaration of Arbroath (Latin: Declaratio Arbroathis; Scots: Declaration o Aiberbrothock; Scottish Gaelic: Tiomnadh Bhruis) is the name usually given to a letter, dated 6 April 1320 at Arbroath, written by Scottish barons and addressed to Pope John XXII. It constituted King Robert I's response to his excommunication for disobeying the pope's demand in 1317 for a truce in the First War of Scottish Independence. The letter asserted the antiquity of the independence of the Kingdom of Scotland, denouncing English attempts to subjugate it.
Generally believed to have been written in Arbroath Abbey by Bernard of Kilwinning (or of Linton), then Chancellor of Scotland and Abbot of Arbroath, and sealed by fifty-one magnates and nobles, the letter is the sole survivor of three created at the time. The others were a letter from the King of Scots, Robert I, and a letter from four Scottish bishops which all made similar points. The Declaration was intended to assert Scotland's status as an independent, sovereign state and defend Scotland's right to use military action when unjustly attacked.
Submitted in Latin, the Declaration was little known until the late 17th century, and is unmentioned by any of Scotland's major 16th-century historians. In the 1680s, the Latin text was printed for the first time and translated into English in the wake of the Glorious Revolution, after which time it was sometimes described as a declaration of independence.
The Declaration was part of a broader diplomatic campaign, which sought to assert Scotland's position as an independent kingdom, rather than its being a feudal land controlled by England's Norman kings, as well as to lift the excommunication of Robert the Bruce. The pope had recognised Edward I of England's claim to overlordship of Scotland in 1305 and Bruce was excommunicated by the Pope for murdering John Comyn before the altar at Greyfriars Church in Dumfries in 1306. This excommunication was lifted in 1308; subsequently the pope threatened Robert with excommunication again if Avignon's demands in 1317 for peace with England were ignored. Warfare continued, and in 1320 John XXII again excommunicated Robert I. In reply, the Declaration was composed and signed and, in response, the papacy rescinded King Robert Bruce's excommunication and thereafter addressed him using his royal title.
The wars of Scottish independence began as a result of the deaths of King Alexander III of Scotland in 1286 and his heir the "Maid of Norway" in 1290, which left the throne of Scotland vacant and the subsequent succession crisis of 1290–1296 ignited a struggle among the Competitors for the Crown of Scotland, chiefly between the House of Comyn, the House of Balliol, and the House of Bruce who all claimed the crown. After July 1296's deposition of King John Balliol by Edward of England and then February 1306's killing of John Comyn III, Robert Bruce's rivals to the throne of Scotland were gone, and Robert was crowned king at Scone that year. Edward I, the "Hammer of Scots", died in 1307; his son and successor Edward II did not renew his father's campaigns in Scotland. In 1309 a parliament held at St Andrews acknowledged Robert's right to rule, received emissaries from the Kingdom of France recognising the Bruce's title, and proclaimed the independence of the kingdom from England.
By 1314 only Edinburgh, Berwick-upon-Tweed, Roxburgh, and Stirling remained in English hands. In June 1314 the Battle of Bannockburn had secured Robert Bruce's position as King of Scots; Stirling, the Central Belt, and much of Lothian came under Robert's control while the defeated Edward II's power on escaping to England via Berwick weakened under the sway of his cousin Henry, Earl of Lancaster. King Robert was thus able to consolidate his power, and sent his brother Edward Bruce to claim the Kingdom of Ireland in 1315 with an army landed in Ulster the previous year with the help of Gaelic lords from the Isles. Edward Bruce died in 1318 without achieving success, but the Scots campaigns in Ireland and in northern England were intended to press for the recognition of Robert's crown by King Edward. At the same time, it undermined the House of Plantagenet's claims to overlordship of the British Isles and halted the Plantagenets' effort to absorb Scotland as had been done in Ireland and Wales. Thus were the Scots nobles confident in their letters to Pope John of the distinct and independent nature of Scotland's kingdom; the Declaration of Arbroath was one such. According to historian David Crouch, "The two nations were mutually hostile kingdoms and peoples, and the ancient idea of Britain as an informal empire of peoples under the English king's presidency was entirely dead."
The text describes the ancient history of Scotland, in particular the Scoti, the Gaelic forebears of the Scots who the Declaration claims have origins in Scythia Major prior to migrating via Spain to Great Britain "1,200 years from the Israelite people's crossing of the Red Sea". The Declaration describes how the Scots had "thrown out the Britons and completely destroyed the Picts", resisted the invasions of "the Norse, the Danes and the English", and "held itself ever since, free from all slavery". It then claims that in the Kingdom of Scotland, "one hundred and thirteen kings have reigned of their own Blood Royal, without interruption by foreigners". The text compares Robert Bruce with the Biblical warriors Judah Maccabee and Joshua.
The Declaration made a number of points: that Edward I of England had unjustly attacked Scotland and perpetrated atrocities; that Robert the Bruce had delivered the Scottish nation from this peril; and, most controversially, that the independence of Scotland was the prerogative of the Scottish people, rather than the King of Scots.
Some have interpreted this last point as an early expression of the concept of popular sovereignty or of support of it. It has been cited as a putative example of an early document supporting.
It has also been argued that the Declaration was not a statement of support for popular sovereignty (and that its signatories would not even have been thinking o such a concept, despite its precedent dating in written tradition at least to the Roman Empire, and t) but a statement of royal 'propaganda' supporting Bruce's faction against Balliol's by extolling his virtues among proofs of his divine right, rather than outwardly claiming the people themselves grant political power which they could be free to withdraw from. A justification was given for the rejection of King John Balliol in whose name William Wallace and Andrew de Moray had rebelled in 1297. The Declaration stated is that Bruce was able to defend Scotland from English aggression whereas King John could not. Nevertheless, the justification in terms of the people of Scotland, even though apparently not intending, primarily to put forward popular sovereignty at a principal level (especially in a modern sense) the concept of conditional legitimacy, as well as the people themselves approaches certain elementary notions of popular sovereignty. The question of the historically rigorous description and its broader significance is part of a broader controversy on the mentioned political concepts and to what extent justification in relation to the people necessarily recognition of popular sovereignty on one hand, and on the other hand of nationalist historical narratives ascribing new contemporary significance to historical documents contrary to their time.
To this man, in as much as he saved our people, and for upholding our freedom, we are bound by right as much as by his merits, and choose to follow him in all that he does.
Whatever the true intentions, the idea of a contract between King and people was advanced to the Pope as a justification for Bruce's coronation whilst John de Balliol, who had abdicated the Scottish throne, still lived as a Papal prisoner.
There is also recent scholarship that suggests that the Declaration was substantially derived from the 1317 Irish Remonstrance, also sent in protest of English actions. There are substantial similarities in content between the 1317 Irish Remonstrance and the Declaration of Arbroath, produced three years later. It is also clear that the drafters of the Declaration of Arbroath would have access to the 1317 Irish Remonstrance, it having been circulated to Scotland in addition to the Pope. It has been suggested therefore that the 1317 Remonstrance was a "prototype" for the Declaration of Arbroath, suggesting Irish-Scottish cooperation in attempts to protest against English interference.
For the full text in Latin and a translation in English, See Declaration of Arbroath on WikiSource.
There are 39 names—eight earls and thirty-one barons—at the start of the document, all of whom may have had their seals appended, probably over the space of some time, possibly weeks, with nobles sending in their seals to be used. The folded foot of the document shows that at least eleven additional barons and freeholders (who were not noble) who were not listed on the head were associated with the letter. On the extant copy of the Declaration there are only 19 seals, and of those 19 people only 12 are named within the document. It is thought likely that at least 11 more seals than the original 39 might have been appended. The Declaration was then taken to the papal court at Avignon by Sir Adam Gordon, Sir Odard de Maubuisson, and Bishop Kininmund who was not yet a bishop and probably included for his scholarship.
The Pope heeded the arguments contained in the Declaration, influenced by the offer of support from the Scots for his long-desired crusade if they no longer had to fear English invasion. He exhorted Edward II in a letter to make peace with the Scots. However, it did not lead to his recognising Robert as King of Scots, and the following year was again persuaded by the English to take their side and issued six bulls to that effect.
Eight years later, on 1 March 1328, the new English king, Edward III, signed a peace treaty between Scotland and England, the Treaty of Edinburgh–Northampton. In this treaty, which was in effect until 1333, Edward renounced all English claims to Scotland. In October 1328, the interdict on Scotland, and the excommunication of its king, were removed by the Pope.
The original copy of the Declaration that was sent to Avignon is lost. The only existing manuscript copy of the Declaration survives among Scotland's state papers, measuring 540mm wide by 675mm long (including the seals), it is held by the National Archives of Scotland in Edinburgh, a part of the National Records of Scotland.
The most widely known English language translation was made by Sir James Fergusson, formerly Keeper of the Records of Scotland, from text that he reconstructed using this extant copy and early copies of the original draft.
G. W. S. Barrow has shown that one passage in particular, often quoted from the Fergusson translation, was carefully written using different parts of The Conspiracy of Catiline by the Roman author, Sallust (86–35 BC) as the direct source:
... for, as long as but a hundred of us remain alive, never will we on any conditions be brought under English rule. It is in truth not for glory, nor riches, nor honours that we are fighting, but for freedom – for that alone, which no honest man gives up but with life itself.
Listed below are the signatories of the Declaration of Arbroath in 1320.
The letter itself is written in Latin. It uses the Latin versions of the signatories' titles, and in some cases, the spelling of names has changed over the years. This list generally uses the titles of the signatories' Wikipedia biographies.
In addition, the names of the following do not appear in the document's text, but their names are written on seal tags and their seals are present:
In 1998 former majority leader Trent Lott succeeded in instituting an annual "National Tartan Day" on 6 April by resolution of the United States Senate. US Senate Resolution 155 of 10 November 1997 states that "the Declaration of Arbroath, the Scottish Declaration of Independence, was signed on April 6, 1320 and the American Declaration of Independence was modeled [sic] on that inspirational document". However, although this influence is accepted by some historians, it is disputed by others.
In 2016 the Declaration of Arbroath was placed on the UK Memory of the World Register, part of UNESCO's Memory of the World Programme.
2020 was the 700th anniversary of the Declaration of Arbroath's composition; an Arbroath 2020 festival was arranged but postponed due to the COVID-19 pandemic. The National Museum of Scotland in Edinburgh planned to display the document to the public for the first time in fifteen years. | [
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"text": "The Declaration of Arbroath (Latin: Declaratio Arbroathis; Scots: Declaration o Aiberbrothock; Scottish Gaelic: Tiomnadh Bhruis) is the name usually given to a letter, dated 6 April 1320 at Arbroath, written by Scottish barons and addressed to Pope John XXII. It constituted King Robert I's response to his excommunication for disobeying the pope's demand in 1317 for a truce in the First War of Scottish Independence. The letter asserted the antiquity of the independence of the Kingdom of Scotland, denouncing English attempts to subjugate it.",
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},
{
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"text": "Generally believed to have been written in Arbroath Abbey by Bernard of Kilwinning (or of Linton), then Chancellor of Scotland and Abbot of Arbroath, and sealed by fifty-one magnates and nobles, the letter is the sole survivor of three created at the time. The others were a letter from the King of Scots, Robert I, and a letter from four Scottish bishops which all made similar points. The Declaration was intended to assert Scotland's status as an independent, sovereign state and defend Scotland's right to use military action when unjustly attacked.",
"title": ""
},
{
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"text": "Submitted in Latin, the Declaration was little known until the late 17th century, and is unmentioned by any of Scotland's major 16th-century historians. In the 1680s, the Latin text was printed for the first time and translated into English in the wake of the Glorious Revolution, after which time it was sometimes described as a declaration of independence.",
"title": ""
},
{
"paragraph_id": 3,
"text": "The Declaration was part of a broader diplomatic campaign, which sought to assert Scotland's position as an independent kingdom, rather than its being a feudal land controlled by England's Norman kings, as well as to lift the excommunication of Robert the Bruce. The pope had recognised Edward I of England's claim to overlordship of Scotland in 1305 and Bruce was excommunicated by the Pope for murdering John Comyn before the altar at Greyfriars Church in Dumfries in 1306. This excommunication was lifted in 1308; subsequently the pope threatened Robert with excommunication again if Avignon's demands in 1317 for peace with England were ignored. Warfare continued, and in 1320 John XXII again excommunicated Robert I. In reply, the Declaration was composed and signed and, in response, the papacy rescinded King Robert Bruce's excommunication and thereafter addressed him using his royal title.",
"title": "Overview"
},
{
"paragraph_id": 4,
"text": "The wars of Scottish independence began as a result of the deaths of King Alexander III of Scotland in 1286 and his heir the \"Maid of Norway\" in 1290, which left the throne of Scotland vacant and the subsequent succession crisis of 1290–1296 ignited a struggle among the Competitors for the Crown of Scotland, chiefly between the House of Comyn, the House of Balliol, and the House of Bruce who all claimed the crown. After July 1296's deposition of King John Balliol by Edward of England and then February 1306's killing of John Comyn III, Robert Bruce's rivals to the throne of Scotland were gone, and Robert was crowned king at Scone that year. Edward I, the \"Hammer of Scots\", died in 1307; his son and successor Edward II did not renew his father's campaigns in Scotland. In 1309 a parliament held at St Andrews acknowledged Robert's right to rule, received emissaries from the Kingdom of France recognising the Bruce's title, and proclaimed the independence of the kingdom from England.",
"title": "Overview"
},
{
"paragraph_id": 5,
"text": "By 1314 only Edinburgh, Berwick-upon-Tweed, Roxburgh, and Stirling remained in English hands. In June 1314 the Battle of Bannockburn had secured Robert Bruce's position as King of Scots; Stirling, the Central Belt, and much of Lothian came under Robert's control while the defeated Edward II's power on escaping to England via Berwick weakened under the sway of his cousin Henry, Earl of Lancaster. King Robert was thus able to consolidate his power, and sent his brother Edward Bruce to claim the Kingdom of Ireland in 1315 with an army landed in Ulster the previous year with the help of Gaelic lords from the Isles. Edward Bruce died in 1318 without achieving success, but the Scots campaigns in Ireland and in northern England were intended to press for the recognition of Robert's crown by King Edward. At the same time, it undermined the House of Plantagenet's claims to overlordship of the British Isles and halted the Plantagenets' effort to absorb Scotland as had been done in Ireland and Wales. Thus were the Scots nobles confident in their letters to Pope John of the distinct and independent nature of Scotland's kingdom; the Declaration of Arbroath was one such. According to historian David Crouch, \"The two nations were mutually hostile kingdoms and peoples, and the ancient idea of Britain as an informal empire of peoples under the English king's presidency was entirely dead.\"",
"title": "Overview"
},
{
"paragraph_id": 6,
"text": "The text describes the ancient history of Scotland, in particular the Scoti, the Gaelic forebears of the Scots who the Declaration claims have origins in Scythia Major prior to migrating via Spain to Great Britain \"1,200 years from the Israelite people's crossing of the Red Sea\". The Declaration describes how the Scots had \"thrown out the Britons and completely destroyed the Picts\", resisted the invasions of \"the Norse, the Danes and the English\", and \"held itself ever since, free from all slavery\". It then claims that in the Kingdom of Scotland, \"one hundred and thirteen kings have reigned of their own Blood Royal, without interruption by foreigners\". The text compares Robert Bruce with the Biblical warriors Judah Maccabee and Joshua.",
"title": "Overview"
},
{
"paragraph_id": 7,
"text": "The Declaration made a number of points: that Edward I of England had unjustly attacked Scotland and perpetrated atrocities; that Robert the Bruce had delivered the Scottish nation from this peril; and, most controversially, that the independence of Scotland was the prerogative of the Scottish people, rather than the King of Scots.",
"title": "Overview"
},
{
"paragraph_id": 8,
"text": "Some have interpreted this last point as an early expression of the concept of popular sovereignty or of support of it. It has been cited as a putative example of an early document supporting.",
"title": "Debates"
},
{
"paragraph_id": 9,
"text": "It has also been argued that the Declaration was not a statement of support for popular sovereignty (and that its signatories would not even have been thinking o such a concept, despite its precedent dating in written tradition at least to the Roman Empire, and t) but a statement of royal 'propaganda' supporting Bruce's faction against Balliol's by extolling his virtues among proofs of his divine right, rather than outwardly claiming the people themselves grant political power which they could be free to withdraw from. A justification was given for the rejection of King John Balliol in whose name William Wallace and Andrew de Moray had rebelled in 1297. The Declaration stated is that Bruce was able to defend Scotland from English aggression whereas King John could not. Nevertheless, the justification in terms of the people of Scotland, even though apparently not intending, primarily to put forward popular sovereignty at a principal level (especially in a modern sense) the concept of conditional legitimacy, as well as the people themselves approaches certain elementary notions of popular sovereignty. The question of the historically rigorous description and its broader significance is part of a broader controversy on the mentioned political concepts and to what extent justification in relation to the people necessarily recognition of popular sovereignty on one hand, and on the other hand of nationalist historical narratives ascribing new contemporary significance to historical documents contrary to their time.",
"title": "Debates"
},
{
"paragraph_id": 10,
"text": "To this man, in as much as he saved our people, and for upholding our freedom, we are bound by right as much as by his merits, and choose to follow him in all that he does.",
"title": "Debates"
},
{
"paragraph_id": 11,
"text": "Whatever the true intentions, the idea of a contract between King and people was advanced to the Pope as a justification for Bruce's coronation whilst John de Balliol, who had abdicated the Scottish throne, still lived as a Papal prisoner.",
"title": "Debates"
},
{
"paragraph_id": 12,
"text": "There is also recent scholarship that suggests that the Declaration was substantially derived from the 1317 Irish Remonstrance, also sent in protest of English actions. There are substantial similarities in content between the 1317 Irish Remonstrance and the Declaration of Arbroath, produced three years later. It is also clear that the drafters of the Declaration of Arbroath would have access to the 1317 Irish Remonstrance, it having been circulated to Scotland in addition to the Pope. It has been suggested therefore that the 1317 Remonstrance was a \"prototype\" for the Declaration of Arbroath, suggesting Irish-Scottish cooperation in attempts to protest against English interference.",
"title": "Debates"
},
{
"paragraph_id": 13,
"text": "For the full text in Latin and a translation in English, See Declaration of Arbroath on WikiSource.",
"title": "Text"
},
{
"paragraph_id": 14,
"text": "There are 39 names—eight earls and thirty-one barons—at the start of the document, all of whom may have had their seals appended, probably over the space of some time, possibly weeks, with nobles sending in their seals to be used. The folded foot of the document shows that at least eleven additional barons and freeholders (who were not noble) who were not listed on the head were associated with the letter. On the extant copy of the Declaration there are only 19 seals, and of those 19 people only 12 are named within the document. It is thought likely that at least 11 more seals than the original 39 might have been appended. The Declaration was then taken to the papal court at Avignon by Sir Adam Gordon, Sir Odard de Maubuisson, and Bishop Kininmund who was not yet a bishop and probably included for his scholarship.",
"title": "Signatories"
},
{
"paragraph_id": 15,
"text": "The Pope heeded the arguments contained in the Declaration, influenced by the offer of support from the Scots for his long-desired crusade if they no longer had to fear English invasion. He exhorted Edward II in a letter to make peace with the Scots. However, it did not lead to his recognising Robert as King of Scots, and the following year was again persuaded by the English to take their side and issued six bulls to that effect.",
"title": "Signatories"
},
{
"paragraph_id": 16,
"text": "Eight years later, on 1 March 1328, the new English king, Edward III, signed a peace treaty between Scotland and England, the Treaty of Edinburgh–Northampton. In this treaty, which was in effect until 1333, Edward renounced all English claims to Scotland. In October 1328, the interdict on Scotland, and the excommunication of its king, were removed by the Pope.",
"title": "Signatories"
},
{
"paragraph_id": 17,
"text": "The original copy of the Declaration that was sent to Avignon is lost. The only existing manuscript copy of the Declaration survives among Scotland's state papers, measuring 540mm wide by 675mm long (including the seals), it is held by the National Archives of Scotland in Edinburgh, a part of the National Records of Scotland.",
"title": "Manuscript"
},
{
"paragraph_id": 18,
"text": "The most widely known English language translation was made by Sir James Fergusson, formerly Keeper of the Records of Scotland, from text that he reconstructed using this extant copy and early copies of the original draft.",
"title": "Manuscript"
},
{
"paragraph_id": 19,
"text": "G. W. S. Barrow has shown that one passage in particular, often quoted from the Fergusson translation, was carefully written using different parts of The Conspiracy of Catiline by the Roman author, Sallust (86–35 BC) as the direct source:",
"title": "Manuscript"
},
{
"paragraph_id": 20,
"text": "... for, as long as but a hundred of us remain alive, never will we on any conditions be brought under English rule. It is in truth not for glory, nor riches, nor honours that we are fighting, but for freedom – for that alone, which no honest man gives up but with life itself.",
"title": "Manuscript"
},
{
"paragraph_id": 21,
"text": "Listed below are the signatories of the Declaration of Arbroath in 1320.",
"title": "List of signatories"
},
{
"paragraph_id": 22,
"text": "The letter itself is written in Latin. It uses the Latin versions of the signatories' titles, and in some cases, the spelling of names has changed over the years. This list generally uses the titles of the signatories' Wikipedia biographies.",
"title": "List of signatories"
},
{
"paragraph_id": 23,
"text": "In addition, the names of the following do not appear in the document's text, but their names are written on seal tags and their seals are present:",
"title": "List of signatories"
},
{
"paragraph_id": 24,
"text": "In 1998 former majority leader Trent Lott succeeded in instituting an annual \"National Tartan Day\" on 6 April by resolution of the United States Senate. US Senate Resolution 155 of 10 November 1997 states that \"the Declaration of Arbroath, the Scottish Declaration of Independence, was signed on April 6, 1320 and the American Declaration of Independence was modeled [sic] on that inspirational document\". However, although this influence is accepted by some historians, it is disputed by others.",
"title": "Legacy"
},
{
"paragraph_id": 25,
"text": "In 2016 the Declaration of Arbroath was placed on the UK Memory of the World Register, part of UNESCO's Memory of the World Programme.",
"title": "Legacy"
},
{
"paragraph_id": 26,
"text": "2020 was the 700th anniversary of the Declaration of Arbroath's composition; an Arbroath 2020 festival was arranged but postponed due to the COVID-19 pandemic. The National Museum of Scotland in Edinburgh planned to display the document to the public for the first time in fifteen years.",
"title": "Legacy"
}
] | The Declaration of Arbroath is the name usually given to a letter, dated 6 April 1320 at Arbroath, written by Scottish barons and addressed to Pope John XXII. It constituted King Robert I's response to his excommunication for disobeying the pope's demand in 1317 for a truce in the First War of Scottish Independence. The letter asserted the antiquity of the independence of the Kingdom of Scotland, denouncing English attempts to subjugate it. Generally believed to have been written in Arbroath Abbey by Bernard of Kilwinning, then Chancellor of Scotland and Abbot of Arbroath, and sealed by fifty-one magnates and nobles, the letter is the sole survivor of three created at the time. The others were a letter from the King of Scots, Robert I, and a letter from four Scottish bishops which all made similar points. The Declaration was intended to assert Scotland's status as an independent, sovereign state and defend Scotland's right to use military action when unjustly attacked. Submitted in Latin, the Declaration was little known until the late 17th century, and is unmentioned by any of Scotland's major 16th-century historians. In the 1680s, the Latin text was printed for the first time and translated into English in the wake of the Glorious Revolution, after which time it was sometimes described as a declaration of independence. | 2001-11-14T21:02:41Z | 2023-11-30T23:27:00Z | [
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8,276 | Digital data | Digital data, in information theory and information systems, is information represented as a string of discrete symbols, each of which can take on one of only a finite number of values from some alphabet, such as letters or digits. An example is a text document, which consists of a string of alphanumeric characters. The most common form of digital data in modern information systems is binary data, which is represented by a string of binary digits (bits) each of which can have one of two values, either 0 or 1.
Digital data can be contrasted with analog data, which is represented by a value from a continuous range of real numbers. Analog data is transmitted by an analog signal, which not only takes on continuous values but can vary continuously with time, a continuous real-valued function of time. An example is the air pressure variation in a sound wave.
The word digital comes from the same source as the words digit and digitus (the Latin word for finger), as fingers are often used for counting. Mathematician George Stibitz of Bell Telephone Laboratories used the word digital in reference to the fast electric pulses emitted by a device designed to aim and fire anti-aircraft guns in 1942. The term is most commonly used in computing and electronics, especially where real-world information is converted to binary numeric form as in digital audio and digital photography.
Since symbols (for example, alphanumeric characters) are not continuous, representing symbols digitally is rather simpler than conversion of continuous or analog information to digital. Instead of sampling and quantization as in analog-to-digital conversion, such techniques as polling and encoding are used.
A symbol input device usually consists of a group of switches that are polled at regular intervals to see which switches are switched. Data will be lost if, within a single polling interval, two switches are pressed, or a switch is pressed, released, and pressed again. This polling can be done by a specialized processor in the device to prevent burdening the main CPU. When a new symbol has been entered, the device typically sends an interrupt, in a specialized format, so that the CPU can read it.
For devices with only a few switches (such as the buttons on a joystick), the status of each can be encoded as bits (usually 0 for released and 1 for pressed) in a single word. This is useful when combinations of key presses are meaningful, and is sometimes used for passing the status of modifier keys on a keyboard (such as shift and control). But it does not scale to support more keys than the number of bits in a single byte or word.
Devices with many switches (such as a computer keyboard) usually arrange these switches in a scan matrix, with the individual switches on the intersections of x and y lines. When a switch is pressed, it connects the corresponding x and y lines together. Polling (often called scanning in this case) is done by activating each x line in sequence and detecting which y lines then have a signal, thus which keys are pressed. When the keyboard processor detects that a key has changed state, it sends a signal to the CPU indicating the scan code of the key and its new state. The symbol is then encoded or converted into a number based on the status of modifier keys and the desired character encoding.
A custom encoding can be used for a specific application with no loss of data. However, using a standard encoding such as ASCII is problematic if a symbol such as 'ß' needs to be converted but is not in the standard.
It is estimated that in the year 1986, less than 1% of the world's technological capacity to store information was digital and in 2007 it was already 94%. The year 2002 is assumed to be the year when humankind was able to store more information in digital than in analog format (the "beginning of the digital age").
Digital data come in these three states: data at rest, data in transit, and data in use. The confidentiality, integrity, and availability have to be managed during the entire lifecycle from 'birth' to the destruction of the data.
All digital information possesses common properties that distinguish it from analog data with respect to communications:
Even though digital signals are generally associated with the binary electronic digital systems used in modern electronics and computing, digital systems are actually ancient, and need not be binary or electronic. | [
{
"paragraph_id": 0,
"text": "Digital data, in information theory and information systems, is information represented as a string of discrete symbols, each of which can take on one of only a finite number of values from some alphabet, such as letters or digits. An example is a text document, which consists of a string of alphanumeric characters. The most common form of digital data in modern information systems is binary data, which is represented by a string of binary digits (bits) each of which can have one of two values, either 0 or 1.",
"title": ""
},
{
"paragraph_id": 1,
"text": "Digital data can be contrasted with analog data, which is represented by a value from a continuous range of real numbers. Analog data is transmitted by an analog signal, which not only takes on continuous values but can vary continuously with time, a continuous real-valued function of time. An example is the air pressure variation in a sound wave.",
"title": ""
},
{
"paragraph_id": 2,
"text": "The word digital comes from the same source as the words digit and digitus (the Latin word for finger), as fingers are often used for counting. Mathematician George Stibitz of Bell Telephone Laboratories used the word digital in reference to the fast electric pulses emitted by a device designed to aim and fire anti-aircraft guns in 1942. The term is most commonly used in computing and electronics, especially where real-world information is converted to binary numeric form as in digital audio and digital photography.",
"title": ""
},
{
"paragraph_id": 3,
"text": "Since symbols (for example, alphanumeric characters) are not continuous, representing symbols digitally is rather simpler than conversion of continuous or analog information to digital. Instead of sampling and quantization as in analog-to-digital conversion, such techniques as polling and encoding are used.",
"title": "Symbol to digital conversion"
},
{
"paragraph_id": 4,
"text": "A symbol input device usually consists of a group of switches that are polled at regular intervals to see which switches are switched. Data will be lost if, within a single polling interval, two switches are pressed, or a switch is pressed, released, and pressed again. This polling can be done by a specialized processor in the device to prevent burdening the main CPU. When a new symbol has been entered, the device typically sends an interrupt, in a specialized format, so that the CPU can read it.",
"title": "Symbol to digital conversion"
},
{
"paragraph_id": 5,
"text": "For devices with only a few switches (such as the buttons on a joystick), the status of each can be encoded as bits (usually 0 for released and 1 for pressed) in a single word. This is useful when combinations of key presses are meaningful, and is sometimes used for passing the status of modifier keys on a keyboard (such as shift and control). But it does not scale to support more keys than the number of bits in a single byte or word.",
"title": "Symbol to digital conversion"
},
{
"paragraph_id": 6,
"text": "Devices with many switches (such as a computer keyboard) usually arrange these switches in a scan matrix, with the individual switches on the intersections of x and y lines. When a switch is pressed, it connects the corresponding x and y lines together. Polling (often called scanning in this case) is done by activating each x line in sequence and detecting which y lines then have a signal, thus which keys are pressed. When the keyboard processor detects that a key has changed state, it sends a signal to the CPU indicating the scan code of the key and its new state. The symbol is then encoded or converted into a number based on the status of modifier keys and the desired character encoding.",
"title": "Symbol to digital conversion"
},
{
"paragraph_id": 7,
"text": "A custom encoding can be used for a specific application with no loss of data. However, using a standard encoding such as ASCII is problematic if a symbol such as 'ß' needs to be converted but is not in the standard.",
"title": "Symbol to digital conversion"
},
{
"paragraph_id": 8,
"text": "It is estimated that in the year 1986, less than 1% of the world's technological capacity to store information was digital and in 2007 it was already 94%. The year 2002 is assumed to be the year when humankind was able to store more information in digital than in analog format (the \"beginning of the digital age\").",
"title": "Symbol to digital conversion"
},
{
"paragraph_id": 9,
"text": "Digital data come in these three states: data at rest, data in transit, and data in use. The confidentiality, integrity, and availability have to be managed during the entire lifecycle from 'birth' to the destruction of the data.",
"title": "States"
},
{
"paragraph_id": 10,
"text": "All digital information possesses common properties that distinguish it from analog data with respect to communications:",
"title": "Properties of digital information"
},
{
"paragraph_id": 11,
"text": "Even though digital signals are generally associated with the binary electronic digital systems used in modern electronics and computing, digital systems are actually ancient, and need not be binary or electronic.",
"title": "Historical digital systems"
}
] | Digital data, in information theory and information systems, is information represented as a string of discrete symbols, each of which can take on one of only a finite number of values from some alphabet, such as letters or digits. An example is a text document, which consists of a string of alphanumeric characters. The most common form of digital data in modern information systems is binary data, which is represented by a string of binary digits (bits) each of which can have one of two values, either 0 or 1. Digital data can be contrasted with analog data, which is represented by a value from a continuous range of real numbers. Analog data is transmitted by an analog signal, which not only takes on continuous values but can vary continuously with time, a continuous real-valued function of time. An example is the air pressure variation in a sound wave. The word digital comes from the same source as the words digit and digitus, as fingers are often used for counting. Mathematician George Stibitz of Bell Telephone Laboratories used the word digital in reference to the fast electric pulses emitted by a device designed to aim and fire anti-aircraft guns in 1942. The term is most commonly used in computing and electronics, especially where real-world information is converted to binary numeric form as in digital audio and digital photography. | 2001-08-03T18:29:29Z | 2023-10-30T01:17:48Z | [
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8,278 | Deduction | Deduction may refer to: | [
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|
8,280 | Demon | A demon is a malevolent supernatural entity. Historically, belief in demons, or stories about demons, occurs in religion, occultism, literature, fiction, mythology, and folklore; as well as in media such as comics, video games, movies, and television series.
Belief in demons probably goes back to the Paleolithic age, stemming from humanity's fear of the unknown, the strange and the horrific. In ancient Near Eastern religions and in the Abrahamic religions, including early Judaism and ancient-medieval Christian demonology, a demon is considered a harmful spiritual entity which may cause demonic possession, calling for an exorcism. Large portions of Jewish demonology, a key influence on Christianity and Islam, originated from a later form of Zoroastrianism, and was transferred to Judaism during the Persian era.
Demons may or may not also be considered to be devils: minions of the Devil. In many traditions, demons are independent operators, with different demons causing different types of evils (destructive natural phenomena, specific diseases, etc.). In religions featuring a principal Devil (e.g. Satan) locked in an eternal struggle with God, demons are often also thought to be subordinates of the principal Devil. As lesser spirits doing the Devil's work, they have additional duties— causing humans to have sinful thoughts and tempting humans to commit sinful actions.
The original Ancient Greek word daimōn (δαίμων) did not carry negative connotations, as it denotes a spirit or divine power. The Greek conception of a daimōn notably appears in the philosophical works of Plato, where it describes the divine inspiration of Socrates.
In Christianity, morally ambivalent daimōn were replaced by demons, forces of evil only striving for corruption. Such demons are not the Greek intermediary spirits, but hostile entities, already known in Iranian beliefs. In Western esotericism and Renaissance magic, which grew out of an amalgamation of Greco-Roman magic, Jewish Aggadah and Christian demonology, a demon is believed to be a spiritual entity that may be conjured and controlled.
Belief in demons remains an important part of many modern religions and occultist traditions. Demons are still feared largely due to their alleged power to possess living creatures. In the contemporary Western occultist tradition (perhaps epitomized by the work of Aleister Crowley), a demon (such as Choronzon, which is Crowley's interpretation of the so-called "Demon of the Abyss") is a useful metaphor for certain inner psychological processes (inner demons), though some may also regard it as an objectively real phenomenon.
The Ancient Greek word δαίμων (daimōn) denotes a spirit or divine power, much like the Latin genius or numen. Daimōn most likely came from the Greek verb daiesthai ("to divide" or "distribute"). The Greek conception of a daimōn notably appears in the philosophical works of Plato, where it describes the divine inspiration of Socrates. The original Greek word daimōn does not carry the negative connotation initially understood by implementation of the Koine δαιμόνιον (daimonion), and later ascribed to any cognate words sharing the root.
The Greek terms do not have any connotations of evil or malevolence. In fact, εὐδαιμονία (eudaimonia, which literally translates as "good-spiritedness") means happiness. By the early centuries of the Roman Empire, cult statues were seen, by Pagans and their Christian neighbors alike, as inhabited by the numinous presence of the Greco-Roman gods: "Like pagans, Christians still sensed and saw the gods and their power, and as something, they had to assume, lay behind it, by an easy traditional shift of opinion they turned these pagan daimones into malevolent 'demons', the troupe of Satan. Far into the Byzantine period, Christians eyed their cities' old pagan statuary as a seat of the demons' presence. It was no longer beautiful, it was infested." The term had first acquired its negative connotations in the Septuagint translation of the Hebrew Bible into Greek, which drew on the mythology of ancient Semitic religions. This was then inherited by the Koine text of the New Testament.
The English use of demon as synonym for devils goes back at least as far as about 825. The German word (Dämon), however, is different from devil (Teufel) and demons as evil spirits, and akin to the original meaning of daimon. The Western Modern era conception of a demon, as in the Ars Goetia, derives seamlessly from the ambient popular culture of Late Antiquity.
The exact definition of "demon" in Egyptology posed a major problem for modern scholarship, since the borders between a deity and a demon are sometimes blurred and the ancient Egyptian language lacks a term for the modern English "demon". Both deities and demons can act as intermediaries to deliver messages to humans. By that, they share some resemblance to the Greek daimon. However, magical writings indicate that ancient Egyptians acknowledged the existence of malevolent demons by highlighting the demon names with red ink. Demons in this culture appeared to be subordinative and related to a specific deity, yet they may have occasionally acted independently of the divine will. The existence of demons can be related to the realm of chaos, beyond the created world. But even this negative connotation cannot be denied in light of the magical texts. The role of demons in relation to the human world remains ambivalent and largely depends on context.
Ancient Egyptian demons can be divided into two classes: "guardians" and "wanderers".> "Guardians" are tied to a specific place; their demonic activity is topographically defined and their function can be benevolent towards those who have the secret knowledge to face them. Demons protecting the underworld may prevent human souls from entering paradise. Only by knowing the right charms is the deceased able to enter the Halls of Osiris. Here, the aggressive nature of the guardian demons is motivated by the need to protect their abodes and not by their evil essence. Accordingly, demons guarded sacred places or the gates to the netherworld. During the Ptolemaic and Roman period, the guardians shifted towards the role of genius loci and they were the focus of local and private cults.
The "wanderers" are associated with possession, mental illness, death and plagues. Many of them serve as executioners for the major deities, such as Ra or Osiris, when ordered to punish humans on earth or in the netherworld. Wanderers can also be agents of chaos, arising from the world beyond creation to bring about misfortune and suffering without any divine instructions, led only by evil motivations. The influences of the wanderers can be warded off and kept at the borders of the human world by the use of magic, but they can never be destroyed. A sub-category of "wanderers" are nightmare demons, which were believed to cause nightmares by entering a human body.
The ancient Mesopotamians believed that the underworld was home to many demons, which are sometimes referred to as "offspring of arali". These demons could sometimes leave the underworld and terrorize mortals on earth. One class of demons that were believed to reside in the underworld were known as galla; their primary purpose appears to have been to drag unfortunate mortals back to Kur. They are frequently referenced in magical texts, and some texts describe them as being seven in number. Several extant poems describe the galla dragging the god Dumuzid into the underworld. Like other demons, however, galla could also be benevolent and, in a hymn from King Gudea of Lagash (c. 2144 – 2124 BCE), a minor god named Ig-alima is described as "the great galla of Girsu".
Lamashtu was a demonic goddess with the "head of a lion, the teeth of a donkey, naked breasts, a hairy body, hands stained (with blood?), long fingers and fingernails, and the feet of Anzû". She was believed to feed on the blood of human infants and was widely blamed as the cause of miscarriages and cot deaths. Although Lamashtu has traditionally been identified as a demoness, the fact that she could cause evil on her own without the permission of other deities strongly indicates that she was seen as a goddess in her own right. Mesopotamian peoples protected against her using amulets and talismans. She was believed to ride in her boat on the river of the underworld and she was associated with donkeys. She was believed to be the daughter of An.
Pazuzu is a demonic god who was well known to the Babylonians and Assyrians throughout the first millennium BCE. He is shown with "a rather canine face with abnormally bulging eyes, a scaly body, a snake-headed penis, the talons of a bird and usually wings". He was believed to be the son of the god Hanbi. He was usually regarded as evil, but he could also sometimes be a beneficent entity who protected against winds bearing pestilence and he was thought to be able to force Lamashtu back to the underworld. Amulets bearing his image were positioned in dwellings to protect infants from Lamashtu and pregnant women frequently wore amulets with his head on them as protection from her.
Šul-pa-e's name means "youthful brilliance", but he was not envisioned as youthful god. According to one tradition, he was the consort of Ninhursag, a tradition which contradicts the usual portrayal of Enki as Ninhursag's consort. In one Sumerian poem, offerings made to Šhul-pa-e in the underworld and, in later mythology, he was one of the demons of the underworld.
According to The Jewish Encyclopedia, originally published in 12 volumes from 1901 to 1906, "In Chaldean mythology the seven evil deities were known as shedu, storm-demons, represented in ox-like form." They were represented as winged bulls, derived from the colossal bulls used as protective jinn of royal palaces.
There are differing opinions in Judaism about the existence or non-existence of demons (shedim or se'irim). Some Rabbinic scholars assert that demons have existed in Talmudic times, but do not exist regularly in present. When prophecy, Divine intuition and Divine inspiration gradually decreased, the demonic powers of impurity have become correspondingly weak, too.
The Hebrew Bible mentions two classes of demonic spirits, the se'irim and the shedim. The word shedim (sing shed or sheyd) appears in two places in the Hebrew Bible. The se'irim (sing. sa'ir, "male goat") are mentioned once in Leviticus 17:7, probably a recollection of Assyrian demons in the shape of goats. The shedim, however, are not pagan demigods, but the foreign gods themselves. Both entities appear in a scriptural context of animal or child sacrifice to non-existent false gods.
Various diseases and ailments were ascribed to demons, particularly those affecting the brain and those of internal nature. Examples include catalepsy, headache, epilepsy and nightmares. There also existed a demon of blindness, "Shabriri" (lit. "dazzling glare") who rested on uncovered water at night and blinded those who drank from it.
Demons supposedly entered the body and caused the disease while overwhelming or "seizing" the victim. To cure such diseases, it was necessary to draw out the evil demons by certain incantations and talismanic performances, at which the Essenes excelled. Josephus, who spoke of demons as "spirits of the wicked which enter into men that are alive and kill them", but which could be driven out by a certain root, witnessed such a performance in the presence of the Emperor Vespasian and ascribed its origin to King Solomon. In mythology, there were few defences against Babylonian demons. The mythical mace Sharur had the power to slay demons such as Asag, a legendary gallu or edimmu of hideous strength.
In the Jerusalem Talmud, notions of shedim ("demons" or "spirits") are almost unknown or occur only very rarely, whereas in the Babylonian Talmud there are many references to shedim and magical incantations. The existence of shedim in general was not questioned by most of the Babylonian Talmudists. As a consequence of the rise of influence of the Babylonian Talmud over that of the Jerusalem Talmud, late rabbis, in general, took as fact the existence of shedim, nor did most of the medieval thinkers question their reality. However, rationalists like Maimonides and Saadia Gaon and others explicitly denied their existence, and completely rejected concepts of demons, evil spirits, negative spiritual influences, attaching and possessing spirits. They thought the essential teaching about shedim and similar spirits is, that they should not be an object of worship, not a reality to be acknowledged or feared. Their point of view eventually became mainstream Jewish understanding.
The opinion of some authors is not clear. Abraham ibn Ezra states that insane people can see the image of se'irim, when they go astray and ascribe to them powers independent from God. It is not clear from his work, if he considered these images of se'irim as manifestations of actual spirits or merely delusions. Despite academic consensus, Rabbis disputed that Maimonies denied the existence of demons entirely. He would only dispute the existence of demons in his own life time, but not that demons had existed once.
Occasionally an angel is called satan in the Babylon Talmud. But satans do not refer to demons as they remain at the service of God: "Stand not in the way of an ox when coming from the pasture, for Satan dances between his horns".
Aggadic tales from the Persian tradition describe the shedim, the mazziḳim ("harmers"), and the ruḥin ("spirits"). There were also lilin ("night spirits"), ṭelane ("shade", or "evening spirits"), ṭiharire ("midday spirits"), and ẓafrire ("morning spirits"), as well as the "demons that bring famine" and "such as cause storm and earthquake". According to some aggadic stories, demons were under the dominion of a king or chief, usually Asmodai.
In Kabbalah, demons are regarded a necessary part of the divine emanation in the material world and a byproduct of human sin (Qlippoth). After they are created, they assume an existence on their own. Demons would attach themselves to the sinner and start to multiply as an act of self-preservation. Medieval Kabbalists characterize such demons as punishing angels of destruction. They are subject to the Divine will, and do not act independently.
Other demonic entities, such as the shedim, might be considered benevolent. The Zohar classifies them as those who are like humans and submit to the Torah, and those who have no fear of God and are like animals.
The sources of demonic influence were thought to originate from the Watchers or Nephilim, who are first mentioned in Genesis 6 and are the focus of 1 Enoch Chapters 1–16, and also in Jubilees 10. The Nephilim were seen as the source of the sin and evil on Earth because they are referenced in Genesis 6:4 before the story of the Flood. In Genesis 6:5, God sees evil in the hearts of men. Ethiopic Enoch refers to Genesis 6:4–5, and provides further description of the story connecting the Nephilim to the corruption of humans. According to the Book of Enoch, sin originates when angels descend from heaven and fornicate with women, birthing giants. The Book of Enoch shows that these fallen angels can lead humans to sin through direct interaction or through providing forbidden knowledge. Most scholars understand the text, that demons originate from the evil spirits of the deceased giants, cursed by God to wander the Earth. Dale Martin disagrees with this interpretation, arguing that the ghosts of the Nephilim are distinct. The evil spirits would make the people sacrifice to the demons, but they were not demons themselves. The spirits are stated in Enoch to "corrupt, fall, be excited, and fall upon the earth, and cause sorrow".
The Book of Jubilees conveys that sin occurs when Cainan accidentally transcribes astrological knowledge used by the Watchers. This differs from Enoch in that it does not place blame on the angels. However, in Jubilees 10:4 the evil spirits of the Watchers are discussed as evil and still remain on Earth to corrupt humans. God binds only 90% of the Watchers and destroys them, leaving 10% to be ruled by Mastema. Because the evil in humans is great, only 10% would be needed to corrupt and lead humans astray. These spirits of the giants are also referred to as "the bastards" in the apotropaic prayer Songs of the Sage, which lists the names of demons the narrator hopes to expel.
To the Qumran community during the Second Temple period, this apotropaic prayer was assigned, stating: "And, I the Sage, declare the grandeur of his radiance in order to frighten and terri[fy] all the spirits of the ravaging angels and the bastard spirits, demons, Liliths, owls" (Dead Sea Scrolls, "Songs of the Sage", Lines 4–5).
In the Veda, gods (deva) and demons (asura) share both the upper world. It is only by the time of the Brahmanas that they are said to inhabit the underworld. The identification of asura with demons stems from the description of asura as "formerly gods" (pūrvadeva). The gods are said to have claimed heaven for themselves and tricked the demons, ending on earth. During the Vedic period, gods aid humans against demons. By that, gods secure their own place in heaven, using humans as tools to defeat their cosmic enemies.
Asura, in the earliest hymns of the Rigveda, originally meant any supernatural spirit, either good or bad. Since the /s/ of the Indic linguistic branch is cognate with the /h/ of the Early Iranian languages, the word asura, representing a category of celestial beings, is a cognate with Old Persian Ahura. Ancient Hinduism tells that Devas (also called suras) and Asuras are half-brothers, sons of the same father Kashyapa; although some of the Devas, such as Varuna, are also called Asuras. Later, during Puranic age, Asura and Rakshasa came to exclusively mean any of a race of anthropomorphic, powerful, possibly evil beings. Daitya (lit. sons of the mother "Diti"), Maya Danava, Rakshasa (lit. from "harm to be guarded against"), and asura are incorrectly translated into English as "demon".
With increase in asceticism during the post-Vedic period, withdrawal of sacrificial rituals was considered a threat to the gods. Ascetic humans or ascetic demons were supposed to be more powerful than gods. Pious, highly enlightened Asuras, such as Prahlada and Vibhishana, are not uncommon. The Asura are not fundamentally against the gods, nor do they tempt humans to fall. Many people metaphorically interpret the Asura as manifestations of the ignoble passions in the human mind and as symbolic devices. There were also cases of power-hungry asuras challenging various aspects of the gods, but only to be defeated eventually and seek forgiveness.
Hinduism advocates the reincarnation and transmigration of souls according to one's karma. Souls (Atman) of the dead are adjudged by the Yama and are accorded various purging punishments before being reborn. Humans that have committed extraordinary wrongs are condemned to roam as lonely, often mischief mongers, spirits for a length of time before being reborn. Many kinds of such spirits (Vetalas, Pishachas, Bhūta) are recognized in the later Hindu texts. According to Hinduism, demons are not inherently evil beings, but good by following their dharma what is being evil and deceitful. However, nothing is purely evil or good, and a demon could eventually abandon his demonic nature.
Belief in demons does not constitute an essential feature in Buddhism. However, since belief in demons were common during the rise of Buddhism, they are integrated into the cycle of Saṃsāra. Accordingly, their malevolent condition is due to their bad karma from their previous lives. When Buddhism spread, it accommodated itself with indigenous popular ideas about demons.
The Zorastrian belief in demons (Daeva, later div) had strong influence on the Abrahamic religions, especially Christianity and Islam. In hell, demons continue to torment the damned.
Book 3 of the Denkard describes demons as the opposite of the creative power of God. As such, they cannot create, but only corrupt, and thus, evil is merely the corruption of the good. Since demons can only destroy, they will ultimately destroy themselves. Chapter 30 questions the reality of demons, since their existence seem to rely on their destruction of good. Therefore, Ahriman and his demons would miss any substance and exist only as absence of good.
Manichaeism was a major religion founded in the third century AD by the Parthian prophet Mani (c. 216–274 AD), in the Sasanian Empire. One of its key concepts is the doctrine of Two Principles and Three Moments. Accordingly, the world could be described as resulting from a past moment, in which two principles (good and evil) were separate, a contemporary moment in which both principles are mixed due to an assault of the world of darkness on the realm of light, and a future moment when both principles are distinct forever. Thus, evil and demons played a significant role within Manichaean teachings.
There are numberless designations for various groups of demonic entities in Manichaean cosmology. The general term used for the beings of the world of darkness is dyw (dev). Before the demons attacked the realm of light, they have been in constant battle and intercourse against each other. It is only in the realm of darkness demons are described in their physical form. After their assault on the world above, they have been overcome by the Living Spirit, and imprisoned in the structure of the world. From that point onwards, they impact human's ethical life, and appear as personified ethical qualities, mostly greed, envy, grief, and wrath (desire for destruction).
Ibn al-Jawzi, in his work Talbīs Iblīs (devils' delusion), credits the Manichaeans with believing that each Light and Darkness (God and the Devil) consist of four bodies and one spirit. The bodies of Light (God) were referred to as angels, while the bodies of Darkness (Devil) were referred to as ifrits. Light and Darkness would multiple by angels and demons respectively.
In The Book of Giants, one of the canonical seven treatises also known from Jewish intertestamental literature, the Grigori (egrēgoroi) beget giant half-demon offspring with human woman. In the Middle Persian version of the Book of Giants they are referred to as kʾw, while in the Coptic Kephalaia as gigas. In accordance with some interpretations of Genesis 6:1–4, the giant offspring became the ancient tyrannic rulers over mankind, until overthrown by the angels of punishment. Nonetheless, these demons are still active in the microcosm, such as Āz and Āwarzōg. Views on stars (abāxtarān) are mixed. On one hand, they are regarded as light particles of the world soul fixed in the sky. On the other hand, stars are identified with powers hindering the soul from leaving the material world. The Third Messenger (Jesus) is said to have chained up demons in the sky. Their offspring, the nephilim (nĕf īlīm) or asrestar (āsarēštārān), Ašqalūn and Nebrō’ēl in particular, play instrumental roles in the creation of Adam and Eve. According to Manichaeism, the watchers, known as angels in Jewish lore, are not considered angels, but demons.
The poem begins with the kings of the Pishdadian dynasty. They defeat and subjugate the demonic divs. Tahmuras commanded the divs and became known as dīvband (binder of demons). Jamshid, the fourth king of the world, ruled over both angels and divs, and served as a high priest of Ahura Mazda (Hormozd). Like his father, he slayed many divs, however, spared some under the condition they teach him new valuable arts, such as writing in different languages. After a just reign over hundreds of years, Jamshid grew haughty and claimed, because of his wealth and power, divinity for himself. Whereupon God withdraws his blessings from him, and his people get unsatisfied with their king. With the ceasing influence of God, the devil gains power and aids Zahhak to usurp the throne. Jamshid dies sawn in two by two demons. Tricked by Ahriman (or Iblis), Zahhak grew two snakes on his shoulders and becomes the demonic serpent-king. The King Kay Kāvus fails to conquer the legendary Mazandaran, the land of divs and gets captured. To save his king, Rustam takes a journey and fights through seven trials. Divs are among the common enemies Rustam faces, the last one the Div-e Sepid, the demonic king of Mazandaran.
The div in the Shahnameh might include both demonic supernatural beings as well as evil humans.
Rustam's battle against the demonic may also have a symbolic meaning: Rustam represents wisdom and rationality, fights the demon, embodiment of passion and instinct. Rustam's victory over the White Div is also a triumph over men's lower drives, and killing the demon is a way to purge the human soul from such evil inclinations. The killing of the White Div is an inevitable act to restore the human king's eyesight. Eliminating the divs is an act of self-preservation to safeguard the good in oneself's, and the part acceptable in a regulated society.
The Algonquian people traditionally believe in a spirit called a wendigo. The spirit is believed to possess people who then become cannibals. In Athabaskan folklore, there is a belief in wechuge, a similar cannibal spirit.
The existence of demons as inherently malicious spirits within Old Testamental texts is absent. Though there are evil spirits sent by YHWH, they can hardly be called demons, since they serve and do not oppose the governing deity. First then the Hebrew Bible was translated into Greek, the "gods of other nations" were merged into a single category of demons (daimones) with implied negativity.
The Greek Daimons were associated with demi-divine entities, deities, illnesses and fortune-telling. The Jewish translators rendered them all as demons, depicting their power as nullified comparable to the description of shedim in the Tanakh. Although all these supernatural powers were translated, none were angels, despite sharing a similar function to that of the Greek Daimon. This established a dualism between the angels on God's side and negatively evaluated demons of pagan origin. Their relationship to the God-head became the main difference between angels and demons, not their degree of benevolence. Both angels and demons might be fierce and terrifying. However, the angels act always at service of the high god of the Israelites, differing from the pagan demons, who represent the powers of foreign deities. The Septuagint refers to evil spirits as demons (daimon).
Through the New Testament, demons appear 55 times, and 46 times in reference to demonic possession or exorcisms. Some old English Bible translations such as King James Version do not have the word 'demon' in their vocabulary and translate it as 'devil'. As adversaries of Jesus, demons are not morally ambivalent spirits, but evil; causes of misery, suffering, and death. They are not tempters, but the cause of pain, suffering, and maladies, both physical and mental. Temptation is reserved for the devil only. Unlike spirits in pagan beliefs, demons are not intermediary spirits who must be sacrificed for the appeasement of a deity. Possession also shows no trace of positivity, contrary to some pagan depictions of spirit possession. They are explicitly said to be ruled by the Devil or Beelzebub. Their origin is unclear, the texts take the existence of demons for granted. Many early Christians, like Irenaeus, Justin Martyr, Clement of Alexandria, and Lactantius assumed demons were ghosts of the Nephilim, known from Intertestamental writings. Because of references to Satan as the lord of demons, and evil angels of Satan throughout the New Testament, other scholars identified fallen angels with demons. Demons as entirely evil entities, who have been born evil, may not fit the proposed origin of evil in free will, taught in alternate or opposing theologies.
Demons are included in biblical interpretation. In the story of Passover, the Bible tells the story as "the Lord struck down all the firstborn in Egypt" (Exodus 12:21–29). In the Book of Jubilees, which is considered canonical only by the Ethiopian Orthodox Church, this same event is told slightly differently: "All the powers of [the demon] Mastema had been let loose to slay all the first-born in the land of Egypt. And the powers of the Lord did everything according as the Lord commanded them." (Jubilees 49:2–4)
In the Genesis flood narrative, the author explains how God was noticing "how corrupt the earth had become, for all the people on earth had corrupted their ways" (Genesis 6:12). In Jubilees, the sins of man are attributed to "the unclean demons [who] began to lead astray the children of the sons of Noah, and to make to err and destroy them" (Jubilees 10:1). In Jubilees, Mastema questions the loyalty of Abraham and tells God to "bid him offer him as a burnt offering on the altar, and Thou wilt see if he will do this command" (Jubilees 17:16). The discrepancy between the story in Jubilees and the story in Genesis 22 exists with the presence of Mastema. In Genesis, God tests the will of Abraham merely to determine whether he is a true follower, however; in Jubilees, Mastema has an agenda behind promoting the sacrifice of Abraham's son, "an even more demonic act than that of Satan in Job". In Jubilees, where Mastema, an angel tasked with tempting mortals into sin and iniquity, requests that God give him a tenth of the spirits of the children of the watchers, demons, in order to aid the process (Jubilees 10:7–9). These demons are passed into Mastema's authority, where once again, an angel is in charge of demonic spirits.
In the Testament of Solomon, written sometime in the first three centuries C.E., the demon Asmodeus explains that he is the son of an angel and a human mother. Another demon describes himself as having died in the "massacre in the age of giants". Beelzeboul, the prince of demons, appears as a fallen angel, not as a demon, but makes people worship demons as their gods.
Since Early Christianity, demonology has developed from a simple acceptance of demons to a complex study that has grown from the original ideas taken from Jewish demonology and Christian scriptures. Christian demonology is studied in depth within the Roman Catholic Church, although many other Christian churches affirm and discuss the existence of demons.
Building upon the few references to daimon in the New Testament, especially the poetry of the Book of Revelation, Christian writers of apocrypha from the second century onwards created a more complicated tapestry of beliefs about "demons" that was largely independent of Christian scripture.
While daimons were considered as both potentially benevolent or malevolent, Origen argued against Celsus that daimons are exclusively evil entities, supporting the later idea of (evil) demons. According to Origen's cosmology, increasing corruption and evil within the soul, the more estranged the soul gets from God. Therefore, Origen opined that the most evil demons are located underground. Besides the fallen angels known from Christian scriptures, Origen talks about Greek daemons, like nature spirits and giants. These creatures were thought to inhabit nature or air and nourish from pagan sacrifices roaming the earth. However, there is no functional difference between the spirits of the underworld and of earth, since both have fallen from perfection into the material world. Origen sums them up as fallen angels and thus equal to demons.
Many ascetics, like Origen and Anthony the Great, described demons as psychological powers, tempting to evil, in contrast to benevolent angels advising good. According to Life of Anthony, written in Greek around 360 by Athanasius of Alexandria, most of the time, the demons were expressed as an internal struggle, inclinations, and temptations. But after Anthony successfully resisted the demons, they would appear in human form to tempt and threaten him even more intensely.
Pseudo-Dionysius the Areopagite described evil as "defiancy" and does not give evil an ontological existence. He explains demons are deficient creatures, who willingly turn themselves towards the unreal and non-existence. Their dangerous nature results not from the power of their nature, but from their tendency to drag others into the "void" and the unreal, away from God.
Michael Psellos proposed the existence of several types of demons, deeply influenced by the material nature of the regions they dwell. The highest and most powerful demons attack the mind of people using their "imaginative action" (phantastikos) to produce illusions in the mind. The lowest demons, on the other hand, are almost mindless, gross, and grunting spirits, which try to possess people instinctively, simply attracted by the warmth and life of humans. These cause diseases, fatal accidents and animalistic behavior in their victims. They are unable to speak, while other lower types of demons might give out false oracles. The demons are divided into:
Invocation of Saints, holy men and women, especially ascetics, reading the Gospel, holy oil or water is said to drive them out. However, Psellos' schemes have been too inconsistent to answer questions about the hierarchy of fallen angels. The devil's position is impossible to assign in this scheme and it does not respond to living perceptions of felt experience and was considered rather impractical to have a lasting effect or impact on Christian demonology.
The contemporary Roman Catholic Church unequivocally teaches that angels and demons are real beings rather than just symbolic devices. The Catholic Church has a cadre of officially sanctioned exorcists which perform many exorcisms each year. The exorcists of the Catholic Church teach that demons attack humans continually but that afflicted persons can be effectively healed and protected either by the formal rite of exorcism, authorized to be performed only by bishops and those they designate, or by prayers of deliverance, which any Christian can offer for themselves or others.
At various times in Christian history, attempts have been made to classify demons according to various proposed demonic hierarchies.
In recent times, scholars doubted that independent demons exist, and rather considers them, aking to Jewish satan, to be servants of God. According to S. N. Chiu, God is shown sending a demon against Saul in 1 Samuel 16 and 18 in order to punish him for the failure to follow God's instructions, showing God as having the power to use demons for his own purposes, putting the demon under his divine authority. According to the Britannica Concise Encyclopedia, demons, despite being typically associated with evil, are often shown to be under divine control, and not acting of their own devices.
In Mandaeism, the World of Darkness (alma d-hšuka), also referred to as Sheol, is the underworld located below Tibil (Earth). It is ruled by its king Ur (Leviathan) and its queen Ruha, mother of the seven planets and twelve constellations. The great dark Ocean of Sup (or Suf) lies in the World of Darkness. The great dividing river of Hitfun, analogous to the river Styx in Greek mythology, separates the World of Darkness from the World of Light. Prominent infernal beings found in the World of Darkness include lilith, nalai (vampire), niuli (hobgoblin), gadalta (ghost), satani (Satan) and various other demons and evil spirits.
Gnosticism largely relies on Greek and Persian dualism, especially on Platonism. In accordance with Platonism, they regarded the idea as good while considering the material and conscious world to be inherently evil. The demonized star-deities of late Persian religion became associated with a demon, thus identifying the seven observable planets with an Archon (demonic ruler). These demons rule over the earth and the realm of planets, representing different desires and passions. According to Origen, the Ophites depicted the world as surrounded by the demonic Leviathan.
Like in Christianity, the term daimons was used for demons and refers to both the Archons as well as to their demonic assistants. Judas Iscariot is, in the Gospel of Judas, portrayed as the thirtheenth daimon for betraying Jesus and a supporter of the Archons.
Examples of Gnostic portrayals of demons can be found in the Apocryphon of John in which they are said to have helped construct the physical Adam and in Pistis Sophia which states they are ruled over by Hekate and punish corrupt souls.
Shayāṭīn (or Daeva of Indo-Iranian religion) are the usual terms for demons in Islamic belief. In Islam demons try to lead humans astray from God, by tempting them to sin, teaching them sorcery and cause mischief among humans. Occult practises albeit not forbidden per se, may include conjuring demons, which requires acts against God's laws and are therefore forbidden, such as illicit blood-sacrifices, abandoning prayer and rejecting fasting. Based on the Islamic view on Solomon, who is widely believed to have been a ruler over genies and demons, Islam has a rich tradition about conjuring demons. Among the demons are the devils (shayatin) and the fiends (div). Both are believed to have worked for Solomon as slaves. While the devils usually appear within a Judeo-Christian background, the div frequently feature in beliefs of Persian and Indian origin. But it is to be noted that in Islam both angels and demons are considered to be the creatures of God and so God has ultimate power over all of them. God sends devils as companions to those who want to disbelief in this world. Even the malicious div are created by God and thus have a place in the world's order.
According to exegesis of the Quran the devils are the offspring of Iblis (Satan). They are said to live until the world ceases to exist, always shadow in humans (and jinn) whispering onto their hearts to lead them astray. Prayers are used to ward off their attacks, dissolving them temporarily. As the counterpart of the angels, they are created rebellious and their abode in Hell is pre-destined. They lack free will and are bound to evil. The ifrit and marid are considered to be two more powerful classes of devils.
According to Abu Ali Bal'ami's work on the history of the world, Wahb ibn Munabbih explained that the divs were the first beings created by God. Some argue the devils were created good, but turned evil by Iblis' act of arrogance, the div were created as vicious creatures and embodiment of evil. When Iblis was still among the angels, he led an army against the spirits on the earth. Among them were the div, who formed two orders; one of which sided with the jinn and were banished with them, condemned to roam the earth. The other, treacherous div joined Iblis in battle, and was exiled to Hell with him. The div are often depicted as sorcerers whose misdeeds are not bound to temptation only. They could cause sickness, mental illnesses, or even turn humans to stone by touching. While the devils frequently appear to ordinary humans to tempt them into everything disapproved by society, the div usually appear to specific heroes.
In the Bahá'í Faith, demons are not regarded as independent evil spirits as they are in some faiths. Rather, evil spirits described in various faiths' traditions, such as Satan, fallen angels, demons and jinn, are metaphors for the base character traits a human being may acquire and manifest when he turns away from God and follows his lower nature. Belief in the existence of ghosts and earthbound spirits is rejected and considered to be the product of superstition.
While some people fear demons, or attempt to exorcise them, others willfully attempt to summon them for knowledge, assistance, or power. The ceremonial magician usually consults a grimoire, which gives the names and abilities of demons as well as detailed instructions for conjuring and controlling them. Grimoires are not limited to demons – some give instructions for the invocation of deity, a process called theurgy. The use of ceremonial magic to call demons is also known as goetia, the name taken from a section in the famous grimoire known as the Lesser Key of Solomon.
According to Rosemary Ellen Guiley, "Demons are not courted or worshipped in contemporary Wicca and Paganism. The existence of negative energies is acknowledged."
Since the Age of Enlightenment, humans have been conceptualized as autonomous individuals, independent from outer invisible forces. Previously, the world was understood to be inhabited by various spirits and demons. With the raise of the rationalistic school of thought, the existence of foreign unknown forces was increasingly rejected. Demons were explained as non-existent. Visions of demons and ghosts were explained as the products of one's own mind. By labelling local deities and demons as superstition, local religious ideas were banished, supporting the promotion of nationwide gods and religions. Because of that, demons became increasingly associated with delusions. Wilkinson Duran states that people who believe in demons are often marginalized in the USA. The notion of possession was at odds with Western philosophy, such as the American Dream and capitalism, which implies the belief that everyone is responsible for their own fate and not at the mercy of external forces.
A minority of Muslim scholars in the Medieval Age, often associated with the Muʿtazila, denied that demons (jinn, devils, divs etc.) have physicality and asserted, they could only affect the mind by waswās (Arabic: وَسْوَاس, 'demonic whisperings in the mind'). Some scholars, like ibn Sina, rejected the reality of jinn altogether. al-Jāḥiẓ and al-Masʿūdī, explained jinn and demons as a merely psychological phenomena. In his Kitāb al-Hayawān, al-Jāḥiẓ states that jinn and demons are the product of loneliness. Such a state induces people to mind-games, causing waswās. Al-Masʿūdī is similarly critical regarding the reality of demons. He states that alleged demonic encounters are the result of fear and "wrong thinking". Alleged encounters are then told to other generations in bedtime stories and poems. When they grow up, they remember such stories in a state of fear or loneliness. This encourages their imaginations, resulting in another alleged demonic encounter.
Psychologist Wilhelm Wundt remarked that "among the activities attributed by myths all over the world to demons, the harmful predominate, so that in popular belief bad demons are clearly older than good ones." Sigmund Freud developed this idea and claimed that the concept of demons was derived from the important relation of the living to the dead: "The fact that demons are always regarded as the spirits of those who have died recently shows better than anything the influence of mourning on the origin of the belief in demons."
M. Scott Peck, an American psychiatrist, wrote two books on the subject, People of the Lie: The Hope For Healing Human Evil and Glimpses of the Devil: A Psychiatrist's Personal Accounts of Possession, Exorcism, and Redemption. Peck describes in some detail several cases involving his patients. In People of the Lie he provides identifying characteristics of an evil person, whom he classified as having a character disorder. In Glimpses of the Devil Peck goes into significant detail describing how he became interested in exorcism in order to debunk the myth of possession by evil spirits – only to be convinced otherwise after encountering two cases which did not fit into any category known to psychology or psychiatry. Peck came to the conclusion that possession was a rare phenomenon related to evil and that possessed people are not actually evil; rather, they are doing battle with the forces of evil.
Although Peck's earlier work was met with widespread popular acceptance, his work on the topics of evil and possession has generated significant debate and derision. Much was made of his association with (and admiration for) the controversial Malachi Martin, a Roman Catholic priest and a former Jesuit, despite the fact that Peck consistently called Martin a liar and a manipulator. Richard Woods, a Roman Catholic priest and theologian, has claimed that Dr. Peck misdiagnosed patients based upon a lack of knowledge regarding dissociative identity disorder (formerly known as multiple personality disorder) and had apparently transgressed the boundaries of professional ethics by attempting to persuade his patients into accepting Christianity. Father Woods admitted that he has never witnessed a genuine case of demonic possession in all his years. | [
{
"paragraph_id": 0,
"text": "A demon is a malevolent supernatural entity. Historically, belief in demons, or stories about demons, occurs in religion, occultism, literature, fiction, mythology, and folklore; as well as in media such as comics, video games, movies, and television series.",
"title": ""
},
{
"paragraph_id": 1,
"text": "Belief in demons probably goes back to the Paleolithic age, stemming from humanity's fear of the unknown, the strange and the horrific. In ancient Near Eastern religions and in the Abrahamic religions, including early Judaism and ancient-medieval Christian demonology, a demon is considered a harmful spiritual entity which may cause demonic possession, calling for an exorcism. Large portions of Jewish demonology, a key influence on Christianity and Islam, originated from a later form of Zoroastrianism, and was transferred to Judaism during the Persian era.",
"title": ""
},
{
"paragraph_id": 2,
"text": "Demons may or may not also be considered to be devils: minions of the Devil. In many traditions, demons are independent operators, with different demons causing different types of evils (destructive natural phenomena, specific diseases, etc.). In religions featuring a principal Devil (e.g. Satan) locked in an eternal struggle with God, demons are often also thought to be subordinates of the principal Devil. As lesser spirits doing the Devil's work, they have additional duties— causing humans to have sinful thoughts and tempting humans to commit sinful actions.",
"title": ""
},
{
"paragraph_id": 3,
"text": "The original Ancient Greek word daimōn (δαίμων) did not carry negative connotations, as it denotes a spirit or divine power. The Greek conception of a daimōn notably appears in the philosophical works of Plato, where it describes the divine inspiration of Socrates.",
"title": ""
},
{
"paragraph_id": 4,
"text": "In Christianity, morally ambivalent daimōn were replaced by demons, forces of evil only striving for corruption. Such demons are not the Greek intermediary spirits, but hostile entities, already known in Iranian beliefs. In Western esotericism and Renaissance magic, which grew out of an amalgamation of Greco-Roman magic, Jewish Aggadah and Christian demonology, a demon is believed to be a spiritual entity that may be conjured and controlled.",
"title": ""
},
{
"paragraph_id": 5,
"text": "Belief in demons remains an important part of many modern religions and occultist traditions. Demons are still feared largely due to their alleged power to possess living creatures. In the contemporary Western occultist tradition (perhaps epitomized by the work of Aleister Crowley), a demon (such as Choronzon, which is Crowley's interpretation of the so-called \"Demon of the Abyss\") is a useful metaphor for certain inner psychological processes (inner demons), though some may also regard it as an objectively real phenomenon.",
"title": ""
},
{
"paragraph_id": 6,
"text": "The Ancient Greek word δαίμων (daimōn) denotes a spirit or divine power, much like the Latin genius or numen. Daimōn most likely came from the Greek verb daiesthai (\"to divide\" or \"distribute\"). The Greek conception of a daimōn notably appears in the philosophical works of Plato, where it describes the divine inspiration of Socrates. The original Greek word daimōn does not carry the negative connotation initially understood by implementation of the Koine δαιμόνιον (daimonion), and later ascribed to any cognate words sharing the root.",
"title": "Etymology"
},
{
"paragraph_id": 7,
"text": "The Greek terms do not have any connotations of evil or malevolence. In fact, εὐδαιμονία (eudaimonia, which literally translates as \"good-spiritedness\") means happiness. By the early centuries of the Roman Empire, cult statues were seen, by Pagans and their Christian neighbors alike, as inhabited by the numinous presence of the Greco-Roman gods: \"Like pagans, Christians still sensed and saw the gods and their power, and as something, they had to assume, lay behind it, by an easy traditional shift of opinion they turned these pagan daimones into malevolent 'demons', the troupe of Satan. Far into the Byzantine period, Christians eyed their cities' old pagan statuary as a seat of the demons' presence. It was no longer beautiful, it was infested.\" The term had first acquired its negative connotations in the Septuagint translation of the Hebrew Bible into Greek, which drew on the mythology of ancient Semitic religions. This was then inherited by the Koine text of the New Testament.",
"title": "Etymology"
},
{
"paragraph_id": 8,
"text": "The English use of demon as synonym for devils goes back at least as far as about 825. The German word (Dämon), however, is different from devil (Teufel) and demons as evil spirits, and akin to the original meaning of daimon. The Western Modern era conception of a demon, as in the Ars Goetia, derives seamlessly from the ambient popular culture of Late Antiquity.",
"title": "Etymology"
},
{
"paragraph_id": 9,
"text": "The exact definition of \"demon\" in Egyptology posed a major problem for modern scholarship, since the borders between a deity and a demon are sometimes blurred and the ancient Egyptian language lacks a term for the modern English \"demon\". Both deities and demons can act as intermediaries to deliver messages to humans. By that, they share some resemblance to the Greek daimon. However, magical writings indicate that ancient Egyptians acknowledged the existence of malevolent demons by highlighting the demon names with red ink. Demons in this culture appeared to be subordinative and related to a specific deity, yet they may have occasionally acted independently of the divine will. The existence of demons can be related to the realm of chaos, beyond the created world. But even this negative connotation cannot be denied in light of the magical texts. The role of demons in relation to the human world remains ambivalent and largely depends on context.",
"title": "Ancient Egypt"
},
{
"paragraph_id": 10,
"text": "Ancient Egyptian demons can be divided into two classes: \"guardians\" and \"wanderers\".> \"Guardians\" are tied to a specific place; their demonic activity is topographically defined and their function can be benevolent towards those who have the secret knowledge to face them. Demons protecting the underworld may prevent human souls from entering paradise. Only by knowing the right charms is the deceased able to enter the Halls of Osiris. Here, the aggressive nature of the guardian demons is motivated by the need to protect their abodes and not by their evil essence. Accordingly, demons guarded sacred places or the gates to the netherworld. During the Ptolemaic and Roman period, the guardians shifted towards the role of genius loci and they were the focus of local and private cults.",
"title": "Ancient Egypt"
},
{
"paragraph_id": 11,
"text": "The \"wanderers\" are associated with possession, mental illness, death and plagues. Many of them serve as executioners for the major deities, such as Ra or Osiris, when ordered to punish humans on earth or in the netherworld. Wanderers can also be agents of chaos, arising from the world beyond creation to bring about misfortune and suffering without any divine instructions, led only by evil motivations. The influences of the wanderers can be warded off and kept at the borders of the human world by the use of magic, but they can never be destroyed. A sub-category of \"wanderers\" are nightmare demons, which were believed to cause nightmares by entering a human body.",
"title": "Ancient Egypt"
},
{
"paragraph_id": 12,
"text": "The ancient Mesopotamians believed that the underworld was home to many demons, which are sometimes referred to as \"offspring of arali\". These demons could sometimes leave the underworld and terrorize mortals on earth. One class of demons that were believed to reside in the underworld were known as galla; their primary purpose appears to have been to drag unfortunate mortals back to Kur. They are frequently referenced in magical texts, and some texts describe them as being seven in number. Several extant poems describe the galla dragging the god Dumuzid into the underworld. Like other demons, however, galla could also be benevolent and, in a hymn from King Gudea of Lagash (c. 2144 – 2124 BCE), a minor god named Ig-alima is described as \"the great galla of Girsu\".",
"title": "Mesopotamia"
},
{
"paragraph_id": 13,
"text": "Lamashtu was a demonic goddess with the \"head of a lion, the teeth of a donkey, naked breasts, a hairy body, hands stained (with blood?), long fingers and fingernails, and the feet of Anzû\". She was believed to feed on the blood of human infants and was widely blamed as the cause of miscarriages and cot deaths. Although Lamashtu has traditionally been identified as a demoness, the fact that she could cause evil on her own without the permission of other deities strongly indicates that she was seen as a goddess in her own right. Mesopotamian peoples protected against her using amulets and talismans. She was believed to ride in her boat on the river of the underworld and she was associated with donkeys. She was believed to be the daughter of An.",
"title": "Mesopotamia"
},
{
"paragraph_id": 14,
"text": "Pazuzu is a demonic god who was well known to the Babylonians and Assyrians throughout the first millennium BCE. He is shown with \"a rather canine face with abnormally bulging eyes, a scaly body, a snake-headed penis, the talons of a bird and usually wings\". He was believed to be the son of the god Hanbi. He was usually regarded as evil, but he could also sometimes be a beneficent entity who protected against winds bearing pestilence and he was thought to be able to force Lamashtu back to the underworld. Amulets bearing his image were positioned in dwellings to protect infants from Lamashtu and pregnant women frequently wore amulets with his head on them as protection from her.",
"title": "Mesopotamia"
},
{
"paragraph_id": 15,
"text": "Šul-pa-e's name means \"youthful brilliance\", but he was not envisioned as youthful god. According to one tradition, he was the consort of Ninhursag, a tradition which contradicts the usual portrayal of Enki as Ninhursag's consort. In one Sumerian poem, offerings made to Šhul-pa-e in the underworld and, in later mythology, he was one of the demons of the underworld.",
"title": "Mesopotamia"
},
{
"paragraph_id": 16,
"text": "According to The Jewish Encyclopedia, originally published in 12 volumes from 1901 to 1906, \"In Chaldean mythology the seven evil deities were known as shedu, storm-demons, represented in ox-like form.\" They were represented as winged bulls, derived from the colossal bulls used as protective jinn of royal palaces.",
"title": "Mesopotamia"
},
{
"paragraph_id": 17,
"text": "There are differing opinions in Judaism about the existence or non-existence of demons (shedim or se'irim). Some Rabbinic scholars assert that demons have existed in Talmudic times, but do not exist regularly in present. When prophecy, Divine intuition and Divine inspiration gradually decreased, the demonic powers of impurity have become correspondingly weak, too.",
"title": "Judaism"
},
{
"paragraph_id": 18,
"text": "The Hebrew Bible mentions two classes of demonic spirits, the se'irim and the shedim. The word shedim (sing shed or sheyd) appears in two places in the Hebrew Bible. The se'irim (sing. sa'ir, \"male goat\") are mentioned once in Leviticus 17:7, probably a recollection of Assyrian demons in the shape of goats. The shedim, however, are not pagan demigods, but the foreign gods themselves. Both entities appear in a scriptural context of animal or child sacrifice to non-existent false gods.",
"title": "Judaism"
},
{
"paragraph_id": 19,
"text": "Various diseases and ailments were ascribed to demons, particularly those affecting the brain and those of internal nature. Examples include catalepsy, headache, epilepsy and nightmares. There also existed a demon of blindness, \"Shabriri\" (lit. \"dazzling glare\") who rested on uncovered water at night and blinded those who drank from it.",
"title": "Judaism"
},
{
"paragraph_id": 20,
"text": "Demons supposedly entered the body and caused the disease while overwhelming or \"seizing\" the victim. To cure such diseases, it was necessary to draw out the evil demons by certain incantations and talismanic performances, at which the Essenes excelled. Josephus, who spoke of demons as \"spirits of the wicked which enter into men that are alive and kill them\", but which could be driven out by a certain root, witnessed such a performance in the presence of the Emperor Vespasian and ascribed its origin to King Solomon. In mythology, there were few defences against Babylonian demons. The mythical mace Sharur had the power to slay demons such as Asag, a legendary gallu or edimmu of hideous strength.",
"title": "Judaism"
},
{
"paragraph_id": 21,
"text": "In the Jerusalem Talmud, notions of shedim (\"demons\" or \"spirits\") are almost unknown or occur only very rarely, whereas in the Babylonian Talmud there are many references to shedim and magical incantations. The existence of shedim in general was not questioned by most of the Babylonian Talmudists. As a consequence of the rise of influence of the Babylonian Talmud over that of the Jerusalem Talmud, late rabbis, in general, took as fact the existence of shedim, nor did most of the medieval thinkers question their reality. However, rationalists like Maimonides and Saadia Gaon and others explicitly denied their existence, and completely rejected concepts of demons, evil spirits, negative spiritual influences, attaching and possessing spirits. They thought the essential teaching about shedim and similar spirits is, that they should not be an object of worship, not a reality to be acknowledged or feared. Their point of view eventually became mainstream Jewish understanding.",
"title": "Judaism"
},
{
"paragraph_id": 22,
"text": "The opinion of some authors is not clear. Abraham ibn Ezra states that insane people can see the image of se'irim, when they go astray and ascribe to them powers independent from God. It is not clear from his work, if he considered these images of se'irim as manifestations of actual spirits or merely delusions. Despite academic consensus, Rabbis disputed that Maimonies denied the existence of demons entirely. He would only dispute the existence of demons in his own life time, but not that demons had existed once.",
"title": "Judaism"
},
{
"paragraph_id": 23,
"text": "Occasionally an angel is called satan in the Babylon Talmud. But satans do not refer to demons as they remain at the service of God: \"Stand not in the way of an ox when coming from the pasture, for Satan dances between his horns\".",
"title": "Judaism"
},
{
"paragraph_id": 24,
"text": "Aggadic tales from the Persian tradition describe the shedim, the mazziḳim (\"harmers\"), and the ruḥin (\"spirits\"). There were also lilin (\"night spirits\"), ṭelane (\"shade\", or \"evening spirits\"), ṭiharire (\"midday spirits\"), and ẓafrire (\"morning spirits\"), as well as the \"demons that bring famine\" and \"such as cause storm and earthquake\". According to some aggadic stories, demons were under the dominion of a king or chief, usually Asmodai.",
"title": "Judaism"
},
{
"paragraph_id": 25,
"text": "In Kabbalah, demons are regarded a necessary part of the divine emanation in the material world and a byproduct of human sin (Qlippoth). After they are created, they assume an existence on their own. Demons would attach themselves to the sinner and start to multiply as an act of self-preservation. Medieval Kabbalists characterize such demons as punishing angels of destruction. They are subject to the Divine will, and do not act independently.",
"title": "Judaism"
},
{
"paragraph_id": 26,
"text": "Other demonic entities, such as the shedim, might be considered benevolent. The Zohar classifies them as those who are like humans and submit to the Torah, and those who have no fear of God and are like animals.",
"title": "Judaism"
},
{
"paragraph_id": 27,
"text": "The sources of demonic influence were thought to originate from the Watchers or Nephilim, who are first mentioned in Genesis 6 and are the focus of 1 Enoch Chapters 1–16, and also in Jubilees 10. The Nephilim were seen as the source of the sin and evil on Earth because they are referenced in Genesis 6:4 before the story of the Flood. In Genesis 6:5, God sees evil in the hearts of men. Ethiopic Enoch refers to Genesis 6:4–5, and provides further description of the story connecting the Nephilim to the corruption of humans. According to the Book of Enoch, sin originates when angels descend from heaven and fornicate with women, birthing giants. The Book of Enoch shows that these fallen angels can lead humans to sin through direct interaction or through providing forbidden knowledge. Most scholars understand the text, that demons originate from the evil spirits of the deceased giants, cursed by God to wander the Earth. Dale Martin disagrees with this interpretation, arguing that the ghosts of the Nephilim are distinct. The evil spirits would make the people sacrifice to the demons, but they were not demons themselves. The spirits are stated in Enoch to \"corrupt, fall, be excited, and fall upon the earth, and cause sorrow\".",
"title": "Judaism"
},
{
"paragraph_id": 28,
"text": "The Book of Jubilees conveys that sin occurs when Cainan accidentally transcribes astrological knowledge used by the Watchers. This differs from Enoch in that it does not place blame on the angels. However, in Jubilees 10:4 the evil spirits of the Watchers are discussed as evil and still remain on Earth to corrupt humans. God binds only 90% of the Watchers and destroys them, leaving 10% to be ruled by Mastema. Because the evil in humans is great, only 10% would be needed to corrupt and lead humans astray. These spirits of the giants are also referred to as \"the bastards\" in the apotropaic prayer Songs of the Sage, which lists the names of demons the narrator hopes to expel.",
"title": "Judaism"
},
{
"paragraph_id": 29,
"text": "To the Qumran community during the Second Temple period, this apotropaic prayer was assigned, stating: \"And, I the Sage, declare the grandeur of his radiance in order to frighten and terri[fy] all the spirits of the ravaging angels and the bastard spirits, demons, Liliths, owls\" (Dead Sea Scrolls, \"Songs of the Sage\", Lines 4–5).",
"title": "Judaism"
},
{
"paragraph_id": 30,
"text": "In the Veda, gods (deva) and demons (asura) share both the upper world. It is only by the time of the Brahmanas that they are said to inhabit the underworld. The identification of asura with demons stems from the description of asura as \"formerly gods\" (pūrvadeva). The gods are said to have claimed heaven for themselves and tricked the demons, ending on earth. During the Vedic period, gods aid humans against demons. By that, gods secure their own place in heaven, using humans as tools to defeat their cosmic enemies.",
"title": "Indian religions"
},
{
"paragraph_id": 31,
"text": "Asura, in the earliest hymns of the Rigveda, originally meant any supernatural spirit, either good or bad. Since the /s/ of the Indic linguistic branch is cognate with the /h/ of the Early Iranian languages, the word asura, representing a category of celestial beings, is a cognate with Old Persian Ahura. Ancient Hinduism tells that Devas (also called suras) and Asuras are half-brothers, sons of the same father Kashyapa; although some of the Devas, such as Varuna, are also called Asuras. Later, during Puranic age, Asura and Rakshasa came to exclusively mean any of a race of anthropomorphic, powerful, possibly evil beings. Daitya (lit. sons of the mother \"Diti\"), Maya Danava, Rakshasa (lit. from \"harm to be guarded against\"), and asura are incorrectly translated into English as \"demon\".",
"title": "Indian religions"
},
{
"paragraph_id": 32,
"text": "With increase in asceticism during the post-Vedic period, withdrawal of sacrificial rituals was considered a threat to the gods. Ascetic humans or ascetic demons were supposed to be more powerful than gods. Pious, highly enlightened Asuras, such as Prahlada and Vibhishana, are not uncommon. The Asura are not fundamentally against the gods, nor do they tempt humans to fall. Many people metaphorically interpret the Asura as manifestations of the ignoble passions in the human mind and as symbolic devices. There were also cases of power-hungry asuras challenging various aspects of the gods, but only to be defeated eventually and seek forgiveness.",
"title": "Indian religions"
},
{
"paragraph_id": 33,
"text": "Hinduism advocates the reincarnation and transmigration of souls according to one's karma. Souls (Atman) of the dead are adjudged by the Yama and are accorded various purging punishments before being reborn. Humans that have committed extraordinary wrongs are condemned to roam as lonely, often mischief mongers, spirits for a length of time before being reborn. Many kinds of such spirits (Vetalas, Pishachas, Bhūta) are recognized in the later Hindu texts. According to Hinduism, demons are not inherently evil beings, but good by following their dharma what is being evil and deceitful. However, nothing is purely evil or good, and a demon could eventually abandon his demonic nature.",
"title": "Indian religions"
},
{
"paragraph_id": 34,
"text": "Belief in demons does not constitute an essential feature in Buddhism. However, since belief in demons were common during the rise of Buddhism, they are integrated into the cycle of Saṃsāra. Accordingly, their malevolent condition is due to their bad karma from their previous lives. When Buddhism spread, it accommodated itself with indigenous popular ideas about demons.",
"title": "Indian religions"
},
{
"paragraph_id": 35,
"text": "The Zorastrian belief in demons (Daeva, later div) had strong influence on the Abrahamic religions, especially Christianity and Islam. In hell, demons continue to torment the damned.",
"title": "Iranian demons"
},
{
"paragraph_id": 36,
"text": "Book 3 of the Denkard describes demons as the opposite of the creative power of God. As such, they cannot create, but only corrupt, and thus, evil is merely the corruption of the good. Since demons can only destroy, they will ultimately destroy themselves. Chapter 30 questions the reality of demons, since their existence seem to rely on their destruction of good. Therefore, Ahriman and his demons would miss any substance and exist only as absence of good.",
"title": "Iranian demons"
},
{
"paragraph_id": 37,
"text": "Manichaeism was a major religion founded in the third century AD by the Parthian prophet Mani (c. 216–274 AD), in the Sasanian Empire. One of its key concepts is the doctrine of Two Principles and Three Moments. Accordingly, the world could be described as resulting from a past moment, in which two principles (good and evil) were separate, a contemporary moment in which both principles are mixed due to an assault of the world of darkness on the realm of light, and a future moment when both principles are distinct forever. Thus, evil and demons played a significant role within Manichaean teachings.",
"title": "Iranian demons"
},
{
"paragraph_id": 38,
"text": "There are numberless designations for various groups of demonic entities in Manichaean cosmology. The general term used for the beings of the world of darkness is dyw (dev). Before the demons attacked the realm of light, they have been in constant battle and intercourse against each other. It is only in the realm of darkness demons are described in their physical form. After their assault on the world above, they have been overcome by the Living Spirit, and imprisoned in the structure of the world. From that point onwards, they impact human's ethical life, and appear as personified ethical qualities, mostly greed, envy, grief, and wrath (desire for destruction).",
"title": "Iranian demons"
},
{
"paragraph_id": 39,
"text": "Ibn al-Jawzi, in his work Talbīs Iblīs (devils' delusion), credits the Manichaeans with believing that each Light and Darkness (God and the Devil) consist of four bodies and one spirit. The bodies of Light (God) were referred to as angels, while the bodies of Darkness (Devil) were referred to as ifrits. Light and Darkness would multiple by angels and demons respectively.",
"title": "Iranian demons"
},
{
"paragraph_id": 40,
"text": "In The Book of Giants, one of the canonical seven treatises also known from Jewish intertestamental literature, the Grigori (egrēgoroi) beget giant half-demon offspring with human woman. In the Middle Persian version of the Book of Giants they are referred to as kʾw, while in the Coptic Kephalaia as gigas. In accordance with some interpretations of Genesis 6:1–4, the giant offspring became the ancient tyrannic rulers over mankind, until overthrown by the angels of punishment. Nonetheless, these demons are still active in the microcosm, such as Āz and Āwarzōg. Views on stars (abāxtarān) are mixed. On one hand, they are regarded as light particles of the world soul fixed in the sky. On the other hand, stars are identified with powers hindering the soul from leaving the material world. The Third Messenger (Jesus) is said to have chained up demons in the sky. Their offspring, the nephilim (nĕf īlīm) or asrestar (āsarēštārān), Ašqalūn and Nebrō’ēl in particular, play instrumental roles in the creation of Adam and Eve. According to Manichaeism, the watchers, known as angels in Jewish lore, are not considered angels, but demons.",
"title": "Iranian demons"
},
{
"paragraph_id": 41,
"text": "The poem begins with the kings of the Pishdadian dynasty. They defeat and subjugate the demonic divs. Tahmuras commanded the divs and became known as dīvband (binder of demons). Jamshid, the fourth king of the world, ruled over both angels and divs, and served as a high priest of Ahura Mazda (Hormozd). Like his father, he slayed many divs, however, spared some under the condition they teach him new valuable arts, such as writing in different languages. After a just reign over hundreds of years, Jamshid grew haughty and claimed, because of his wealth and power, divinity for himself. Whereupon God withdraws his blessings from him, and his people get unsatisfied with their king. With the ceasing influence of God, the devil gains power and aids Zahhak to usurp the throne. Jamshid dies sawn in two by two demons. Tricked by Ahriman (or Iblis), Zahhak grew two snakes on his shoulders and becomes the demonic serpent-king. The King Kay Kāvus fails to conquer the legendary Mazandaran, the land of divs and gets captured. To save his king, Rustam takes a journey and fights through seven trials. Divs are among the common enemies Rustam faces, the last one the Div-e Sepid, the demonic king of Mazandaran.",
"title": "Iranian demons"
},
{
"paragraph_id": 42,
"text": "The div in the Shahnameh might include both demonic supernatural beings as well as evil humans.",
"title": "Iranian demons"
},
{
"paragraph_id": 43,
"text": "Rustam's battle against the demonic may also have a symbolic meaning: Rustam represents wisdom and rationality, fights the demon, embodiment of passion and instinct. Rustam's victory over the White Div is also a triumph over men's lower drives, and killing the demon is a way to purge the human soul from such evil inclinations. The killing of the White Div is an inevitable act to restore the human king's eyesight. Eliminating the divs is an act of self-preservation to safeguard the good in oneself's, and the part acceptable in a regulated society.",
"title": "Iranian demons"
},
{
"paragraph_id": 44,
"text": "The Algonquian people traditionally believe in a spirit called a wendigo. The spirit is believed to possess people who then become cannibals. In Athabaskan folklore, there is a belief in wechuge, a similar cannibal spirit.",
"title": "Native North American demons"
},
{
"paragraph_id": 45,
"text": "The existence of demons as inherently malicious spirits within Old Testamental texts is absent. Though there are evil spirits sent by YHWH, they can hardly be called demons, since they serve and do not oppose the governing deity. First then the Hebrew Bible was translated into Greek, the \"gods of other nations\" were merged into a single category of demons (daimones) with implied negativity.",
"title": "Christianity"
},
{
"paragraph_id": 46,
"text": "The Greek Daimons were associated with demi-divine entities, deities, illnesses and fortune-telling. The Jewish translators rendered them all as demons, depicting their power as nullified comparable to the description of shedim in the Tanakh. Although all these supernatural powers were translated, none were angels, despite sharing a similar function to that of the Greek Daimon. This established a dualism between the angels on God's side and negatively evaluated demons of pagan origin. Their relationship to the God-head became the main difference between angels and demons, not their degree of benevolence. Both angels and demons might be fierce and terrifying. However, the angels act always at service of the high god of the Israelites, differing from the pagan demons, who represent the powers of foreign deities. The Septuagint refers to evil spirits as demons (daimon).",
"title": "Christianity"
},
{
"paragraph_id": 47,
"text": "Through the New Testament, demons appear 55 times, and 46 times in reference to demonic possession or exorcisms. Some old English Bible translations such as King James Version do not have the word 'demon' in their vocabulary and translate it as 'devil'. As adversaries of Jesus, demons are not morally ambivalent spirits, but evil; causes of misery, suffering, and death. They are not tempters, but the cause of pain, suffering, and maladies, both physical and mental. Temptation is reserved for the devil only. Unlike spirits in pagan beliefs, demons are not intermediary spirits who must be sacrificed for the appeasement of a deity. Possession also shows no trace of positivity, contrary to some pagan depictions of spirit possession. They are explicitly said to be ruled by the Devil or Beelzebub. Their origin is unclear, the texts take the existence of demons for granted. Many early Christians, like Irenaeus, Justin Martyr, Clement of Alexandria, and Lactantius assumed demons were ghosts of the Nephilim, known from Intertestamental writings. Because of references to Satan as the lord of demons, and evil angels of Satan throughout the New Testament, other scholars identified fallen angels with demons. Demons as entirely evil entities, who have been born evil, may not fit the proposed origin of evil in free will, taught in alternate or opposing theologies.",
"title": "Christianity"
},
{
"paragraph_id": 48,
"text": "Demons are included in biblical interpretation. In the story of Passover, the Bible tells the story as \"the Lord struck down all the firstborn in Egypt\" (Exodus 12:21–29). In the Book of Jubilees, which is considered canonical only by the Ethiopian Orthodox Church, this same event is told slightly differently: \"All the powers of [the demon] Mastema had been let loose to slay all the first-born in the land of Egypt. And the powers of the Lord did everything according as the Lord commanded them.\" (Jubilees 49:2–4)",
"title": "Christianity"
},
{
"paragraph_id": 49,
"text": "In the Genesis flood narrative, the author explains how God was noticing \"how corrupt the earth had become, for all the people on earth had corrupted their ways\" (Genesis 6:12). In Jubilees, the sins of man are attributed to \"the unclean demons [who] began to lead astray the children of the sons of Noah, and to make to err and destroy them\" (Jubilees 10:1). In Jubilees, Mastema questions the loyalty of Abraham and tells God to \"bid him offer him as a burnt offering on the altar, and Thou wilt see if he will do this command\" (Jubilees 17:16). The discrepancy between the story in Jubilees and the story in Genesis 22 exists with the presence of Mastema. In Genesis, God tests the will of Abraham merely to determine whether he is a true follower, however; in Jubilees, Mastema has an agenda behind promoting the sacrifice of Abraham's son, \"an even more demonic act than that of Satan in Job\". In Jubilees, where Mastema, an angel tasked with tempting mortals into sin and iniquity, requests that God give him a tenth of the spirits of the children of the watchers, demons, in order to aid the process (Jubilees 10:7–9). These demons are passed into Mastema's authority, where once again, an angel is in charge of demonic spirits.",
"title": "Christianity"
},
{
"paragraph_id": 50,
"text": "In the Testament of Solomon, written sometime in the first three centuries C.E., the demon Asmodeus explains that he is the son of an angel and a human mother. Another demon describes himself as having died in the \"massacre in the age of giants\". Beelzeboul, the prince of demons, appears as a fallen angel, not as a demon, but makes people worship demons as their gods.",
"title": "Christianity"
},
{
"paragraph_id": 51,
"text": "Since Early Christianity, demonology has developed from a simple acceptance of demons to a complex study that has grown from the original ideas taken from Jewish demonology and Christian scriptures. Christian demonology is studied in depth within the Roman Catholic Church, although many other Christian churches affirm and discuss the existence of demons.",
"title": "Christianity"
},
{
"paragraph_id": 52,
"text": "Building upon the few references to daimon in the New Testament, especially the poetry of the Book of Revelation, Christian writers of apocrypha from the second century onwards created a more complicated tapestry of beliefs about \"demons\" that was largely independent of Christian scripture.",
"title": "Christianity"
},
{
"paragraph_id": 53,
"text": "While daimons were considered as both potentially benevolent or malevolent, Origen argued against Celsus that daimons are exclusively evil entities, supporting the later idea of (evil) demons. According to Origen's cosmology, increasing corruption and evil within the soul, the more estranged the soul gets from God. Therefore, Origen opined that the most evil demons are located underground. Besides the fallen angels known from Christian scriptures, Origen talks about Greek daemons, like nature spirits and giants. These creatures were thought to inhabit nature or air and nourish from pagan sacrifices roaming the earth. However, there is no functional difference between the spirits of the underworld and of earth, since both have fallen from perfection into the material world. Origen sums them up as fallen angels and thus equal to demons.",
"title": "Christianity"
},
{
"paragraph_id": 54,
"text": "Many ascetics, like Origen and Anthony the Great, described demons as psychological powers, tempting to evil, in contrast to benevolent angels advising good. According to Life of Anthony, written in Greek around 360 by Athanasius of Alexandria, most of the time, the demons were expressed as an internal struggle, inclinations, and temptations. But after Anthony successfully resisted the demons, they would appear in human form to tempt and threaten him even more intensely.",
"title": "Christianity"
},
{
"paragraph_id": 55,
"text": "Pseudo-Dionysius the Areopagite described evil as \"defiancy\" and does not give evil an ontological existence. He explains demons are deficient creatures, who willingly turn themselves towards the unreal and non-existence. Their dangerous nature results not from the power of their nature, but from their tendency to drag others into the \"void\" and the unreal, away from God.",
"title": "Christianity"
},
{
"paragraph_id": 56,
"text": "Michael Psellos proposed the existence of several types of demons, deeply influenced by the material nature of the regions they dwell. The highest and most powerful demons attack the mind of people using their \"imaginative action\" (phantastikos) to produce illusions in the mind. The lowest demons, on the other hand, are almost mindless, gross, and grunting spirits, which try to possess people instinctively, simply attracted by the warmth and life of humans. These cause diseases, fatal accidents and animalistic behavior in their victims. They are unable to speak, while other lower types of demons might give out false oracles. The demons are divided into:",
"title": "Christianity"
},
{
"paragraph_id": 57,
"text": "Invocation of Saints, holy men and women, especially ascetics, reading the Gospel, holy oil or water is said to drive them out. However, Psellos' schemes have been too inconsistent to answer questions about the hierarchy of fallen angels. The devil's position is impossible to assign in this scheme and it does not respond to living perceptions of felt experience and was considered rather impractical to have a lasting effect or impact on Christian demonology.",
"title": "Christianity"
},
{
"paragraph_id": 58,
"text": "The contemporary Roman Catholic Church unequivocally teaches that angels and demons are real beings rather than just symbolic devices. The Catholic Church has a cadre of officially sanctioned exorcists which perform many exorcisms each year. The exorcists of the Catholic Church teach that demons attack humans continually but that afflicted persons can be effectively healed and protected either by the formal rite of exorcism, authorized to be performed only by bishops and those they designate, or by prayers of deliverance, which any Christian can offer for themselves or others.",
"title": "Christianity"
},
{
"paragraph_id": 59,
"text": "At various times in Christian history, attempts have been made to classify demons according to various proposed demonic hierarchies.",
"title": "Christianity"
},
{
"paragraph_id": 60,
"text": "In recent times, scholars doubted that independent demons exist, and rather considers them, aking to Jewish satan, to be servants of God. According to S. N. Chiu, God is shown sending a demon against Saul in 1 Samuel 16 and 18 in order to punish him for the failure to follow God's instructions, showing God as having the power to use demons for his own purposes, putting the demon under his divine authority. According to the Britannica Concise Encyclopedia, demons, despite being typically associated with evil, are often shown to be under divine control, and not acting of their own devices.",
"title": "Christianity"
},
{
"paragraph_id": 61,
"text": "In Mandaeism, the World of Darkness (alma d-hšuka), also referred to as Sheol, is the underworld located below Tibil (Earth). It is ruled by its king Ur (Leviathan) and its queen Ruha, mother of the seven planets and twelve constellations. The great dark Ocean of Sup (or Suf) lies in the World of Darkness. The great dividing river of Hitfun, analogous to the river Styx in Greek mythology, separates the World of Darkness from the World of Light. Prominent infernal beings found in the World of Darkness include lilith, nalai (vampire), niuli (hobgoblin), gadalta (ghost), satani (Satan) and various other demons and evil spirits.",
"title": "Mandaeism"
},
{
"paragraph_id": 62,
"text": "Gnosticism largely relies on Greek and Persian dualism, especially on Platonism. In accordance with Platonism, they regarded the idea as good while considering the material and conscious world to be inherently evil. The demonized star-deities of late Persian religion became associated with a demon, thus identifying the seven observable planets with an Archon (demonic ruler). These demons rule over the earth and the realm of planets, representing different desires and passions. According to Origen, the Ophites depicted the world as surrounded by the demonic Leviathan.",
"title": "Gnosticism"
},
{
"paragraph_id": 63,
"text": "Like in Christianity, the term daimons was used for demons and refers to both the Archons as well as to their demonic assistants. Judas Iscariot is, in the Gospel of Judas, portrayed as the thirtheenth daimon for betraying Jesus and a supporter of the Archons.",
"title": "Gnosticism"
},
{
"paragraph_id": 64,
"text": "Examples of Gnostic portrayals of demons can be found in the Apocryphon of John in which they are said to have helped construct the physical Adam and in Pistis Sophia which states they are ruled over by Hekate and punish corrupt souls.",
"title": "Gnosticism"
},
{
"paragraph_id": 65,
"text": "Shayāṭīn (or Daeva of Indo-Iranian religion) are the usual terms for demons in Islamic belief. In Islam demons try to lead humans astray from God, by tempting them to sin, teaching them sorcery and cause mischief among humans. Occult practises albeit not forbidden per se, may include conjuring demons, which requires acts against God's laws and are therefore forbidden, such as illicit blood-sacrifices, abandoning prayer and rejecting fasting. Based on the Islamic view on Solomon, who is widely believed to have been a ruler over genies and demons, Islam has a rich tradition about conjuring demons. Among the demons are the devils (shayatin) and the fiends (div). Both are believed to have worked for Solomon as slaves. While the devils usually appear within a Judeo-Christian background, the div frequently feature in beliefs of Persian and Indian origin. But it is to be noted that in Islam both angels and demons are considered to be the creatures of God and so God has ultimate power over all of them. God sends devils as companions to those who want to disbelief in this world. Even the malicious div are created by God and thus have a place in the world's order.",
"title": "Islam"
},
{
"paragraph_id": 66,
"text": "According to exegesis of the Quran the devils are the offspring of Iblis (Satan). They are said to live until the world ceases to exist, always shadow in humans (and jinn) whispering onto their hearts to lead them astray. Prayers are used to ward off their attacks, dissolving them temporarily. As the counterpart of the angels, they are created rebellious and their abode in Hell is pre-destined. They lack free will and are bound to evil. The ifrit and marid are considered to be two more powerful classes of devils.",
"title": "Islam"
},
{
"paragraph_id": 67,
"text": "According to Abu Ali Bal'ami's work on the history of the world, Wahb ibn Munabbih explained that the divs were the first beings created by God. Some argue the devils were created good, but turned evil by Iblis' act of arrogance, the div were created as vicious creatures and embodiment of evil. When Iblis was still among the angels, he led an army against the spirits on the earth. Among them were the div, who formed two orders; one of which sided with the jinn and were banished with them, condemned to roam the earth. The other, treacherous div joined Iblis in battle, and was exiled to Hell with him. The div are often depicted as sorcerers whose misdeeds are not bound to temptation only. They could cause sickness, mental illnesses, or even turn humans to stone by touching. While the devils frequently appear to ordinary humans to tempt them into everything disapproved by society, the div usually appear to specific heroes.",
"title": "Islam"
},
{
"paragraph_id": 68,
"text": "In the Bahá'í Faith, demons are not regarded as independent evil spirits as they are in some faiths. Rather, evil spirits described in various faiths' traditions, such as Satan, fallen angels, demons and jinn, are metaphors for the base character traits a human being may acquire and manifest when he turns away from God and follows his lower nature. Belief in the existence of ghosts and earthbound spirits is rejected and considered to be the product of superstition.",
"title": "Bahá'í Faith"
},
{
"paragraph_id": 69,
"text": "While some people fear demons, or attempt to exorcise them, others willfully attempt to summon them for knowledge, assistance, or power. The ceremonial magician usually consults a grimoire, which gives the names and abilities of demons as well as detailed instructions for conjuring and controlling them. Grimoires are not limited to demons – some give instructions for the invocation of deity, a process called theurgy. The use of ceremonial magic to call demons is also known as goetia, the name taken from a section in the famous grimoire known as the Lesser Key of Solomon.",
"title": "Ceremonial magic"
},
{
"paragraph_id": 70,
"text": "According to Rosemary Ellen Guiley, \"Demons are not courted or worshipped in contemporary Wicca and Paganism. The existence of negative energies is acknowledged.\"",
"title": "Wicca"
},
{
"paragraph_id": 71,
"text": "Since the Age of Enlightenment, humans have been conceptualized as autonomous individuals, independent from outer invisible forces. Previously, the world was understood to be inhabited by various spirits and demons. With the raise of the rationalistic school of thought, the existence of foreign unknown forces was increasingly rejected. Demons were explained as non-existent. Visions of demons and ghosts were explained as the products of one's own mind. By labelling local deities and demons as superstition, local religious ideas were banished, supporting the promotion of nationwide gods and religions. Because of that, demons became increasingly associated with delusions. Wilkinson Duran states that people who believe in demons are often marginalized in the USA. The notion of possession was at odds with Western philosophy, such as the American Dream and capitalism, which implies the belief that everyone is responsible for their own fate and not at the mercy of external forces.",
"title": "In modernity"
},
{
"paragraph_id": 72,
"text": "A minority of Muslim scholars in the Medieval Age, often associated with the Muʿtazila, denied that demons (jinn, devils, divs etc.) have physicality and asserted, they could only affect the mind by waswās (Arabic: وَسْوَاس, 'demonic whisperings in the mind'). Some scholars, like ibn Sina, rejected the reality of jinn altogether. al-Jāḥiẓ and al-Masʿūdī, explained jinn and demons as a merely psychological phenomena. In his Kitāb al-Hayawān, al-Jāḥiẓ states that jinn and demons are the product of loneliness. Such a state induces people to mind-games, causing waswās. Al-Masʿūdī is similarly critical regarding the reality of demons. He states that alleged demonic encounters are the result of fear and \"wrong thinking\". Alleged encounters are then told to other generations in bedtime stories and poems. When they grow up, they remember such stories in a state of fear or loneliness. This encourages their imaginations, resulting in another alleged demonic encounter.",
"title": "Psychological approach"
},
{
"paragraph_id": 73,
"text": "Psychologist Wilhelm Wundt remarked that \"among the activities attributed by myths all over the world to demons, the harmful predominate, so that in popular belief bad demons are clearly older than good ones.\" Sigmund Freud developed this idea and claimed that the concept of demons was derived from the important relation of the living to the dead: \"The fact that demons are always regarded as the spirits of those who have died recently shows better than anything the influence of mourning on the origin of the belief in demons.\"",
"title": "Psychological approach"
},
{
"paragraph_id": 74,
"text": "M. Scott Peck, an American psychiatrist, wrote two books on the subject, People of the Lie: The Hope For Healing Human Evil and Glimpses of the Devil: A Psychiatrist's Personal Accounts of Possession, Exorcism, and Redemption. Peck describes in some detail several cases involving his patients. In People of the Lie he provides identifying characteristics of an evil person, whom he classified as having a character disorder. In Glimpses of the Devil Peck goes into significant detail describing how he became interested in exorcism in order to debunk the myth of possession by evil spirits – only to be convinced otherwise after encountering two cases which did not fit into any category known to psychology or psychiatry. Peck came to the conclusion that possession was a rare phenomenon related to evil and that possessed people are not actually evil; rather, they are doing battle with the forces of evil.",
"title": "Psychological approach"
},
{
"paragraph_id": 75,
"text": "Although Peck's earlier work was met with widespread popular acceptance, his work on the topics of evil and possession has generated significant debate and derision. Much was made of his association with (and admiration for) the controversial Malachi Martin, a Roman Catholic priest and a former Jesuit, despite the fact that Peck consistently called Martin a liar and a manipulator. Richard Woods, a Roman Catholic priest and theologian, has claimed that Dr. Peck misdiagnosed patients based upon a lack of knowledge regarding dissociative identity disorder (formerly known as multiple personality disorder) and had apparently transgressed the boundaries of professional ethics by attempting to persuade his patients into accepting Christianity. Father Woods admitted that he has never witnessed a genuine case of demonic possession in all his years.",
"title": "Psychological approach"
}
] | A demon is a malevolent supernatural entity. Historically, belief in demons, or stories about demons, occurs in religion, occultism, literature, fiction, mythology, and folklore; as well as in media such as comics, video games, movies, and television series. Belief in demons probably goes back to the Paleolithic age, stemming from humanity's fear of the unknown, the strange and the horrific. In ancient Near Eastern religions and in the Abrahamic religions, including early Judaism and ancient-medieval Christian demonology, a demon is considered a harmful spiritual entity which may cause demonic possession, calling for an exorcism. Large portions of Jewish demonology, a key influence on Christianity and Islam, originated from a later form of Zoroastrianism, and was transferred to Judaism during the Persian era. Demons may or may not also be considered to be devils: minions of the Devil. In many traditions, demons are independent operators, with different demons causing different types of evils. In religions featuring a principal Devil locked in an eternal struggle with God, demons are often also thought to be subordinates of the principal Devil. As lesser spirits doing the Devil's work, they have additional duties— causing humans to have sinful thoughts and tempting humans to commit sinful actions. The original Ancient Greek word daimōn (δαίμων) did not carry negative connotations, as it denotes a spirit or divine power. The Greek conception of a daimōn notably appears in the philosophical works of Plato, where it describes the divine inspiration of Socrates. In Christianity, morally ambivalent daimōn were replaced by demons, forces of evil only striving for corruption. Such demons are not the Greek intermediary spirits, but hostile entities, already known in Iranian beliefs. In Western esotericism and Renaissance magic, which grew out of an amalgamation of Greco-Roman magic, Jewish Aggadah and Christian demonology, a demon is believed to be a spiritual entity that may be conjured and controlled. Belief in demons remains an important part of many modern religions and occultist traditions. Demons are still feared largely due to their alleged power to possess living creatures. In the contemporary Western occultist tradition, a demon is a useful metaphor for certain inner psychological processes, though some may also regard it as an objectively real phenomenon. | 2001-08-06T09:59:52Z | 2023-12-28T12:05:40Z | [
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8,286 | Domino effect | A domino effect or chain reaction is the cumulative effect produced when one event sets off a chain of similar or other events. This term is best known as a mechanical effect and is used as an analogy to a falling row of dominoes. It typically refers to a linked sequence of events where the time between successive events is relatively small.
The term domino effect can be used literally (an observed series of actual collisions) or metaphorically (causal linkages within systems such as global finance or politics). The term is used both to imply that an event is inevitable or highly likely (as it has already started to happen), and conversely to imply that an event is impossible or highly unlikely (the one domino left standing).
The mechanical domino effect is exploited in Rube Goldberg machines. | [
{
"paragraph_id": 0,
"text": "A domino effect or chain reaction is the cumulative effect produced when one event sets off a chain of similar or other events. This term is best known as a mechanical effect and is used as an analogy to a falling row of dominoes. It typically refers to a linked sequence of events where the time between successive events is relatively small.",
"title": ""
},
{
"paragraph_id": 1,
"text": "The term domino effect can be used literally (an observed series of actual collisions) or metaphorically (causal linkages within systems such as global finance or politics). The term is used both to imply that an event is inevitable or highly likely (as it has already started to happen), and conversely to imply that an event is impossible or highly unlikely (the one domino left standing).",
"title": ""
},
{
"paragraph_id": 2,
"text": "The mechanical domino effect is exploited in Rube Goldberg machines.",
"title": ""
}
] | A domino effect or chain reaction is the cumulative effect produced when one event sets off a chain of similar or other events. This term is best known as a mechanical effect and is used as an analogy to a falling row of dominoes. It typically refers to a linked sequence of events where the time between successive events is relatively small. The term domino effect can be used literally or metaphorically. The term is used both to imply that an event is inevitable or highly likely, and conversely to imply that an event is impossible or highly unlikely. The mechanical domino effect is exploited in Rube Goldberg machines. | 2001-08-08T20:53:57Z | 2023-12-17T15:15:17Z | [
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8,293 | Diffusion pump | Diffusion pumps use a high speed jet of vapor to direct gas molecules in the pump throat down into the bottom of the pump and out the exhaust. They were the first type of high vacuum pumps operating in the regime of free molecular flow, where the movement of the gas molecules can be better understood as diffusion than by conventional fluid dynamics. Invented in 1915 by Wolfgang Gaede, he named it a diffusion pump since his design was based on the finding that gas cannot diffuse against the vapor stream, but will be carried with it to the exhaust. However, the principle of operation might be more precisely described as gas-jet pump, since diffusion also plays a role in other types of high vacuum pumps. In modern textbooks, the diffusion pump is categorized as a momentum transfer pump.
The diffusion pump is widely used in both industrial and research applications. Most modern diffusion pumps use silicone oil or polyphenyl ethers as the working fluid.
In the late 19th century, most vacuums were created using a Sprengel pump, which had the advantage of being very simple to operate, and capable of achieving quite good vacuum given enough time. Compared to later pumps, however, the pumping speed was very slow and the vapor pressure of the liquid mercury limited the ultimate vacuum.
Following his invention of the molecular pump, the diffusion pump was invented in 1915 by Wolfgang Gaede, and originally used elemental mercury as the working fluid. After its invention, the design was quickly commercialized by Leybold.
It was then improved by Irving Langmuir and W. Crawford. Cecil Reginald Burch discovered the possibility of using silicone oil in 1928.
An oil diffusion pump is used to achieve higher vacuum (lower pressure) than is possible by use of positive displacement pumps alone. Although its use has been mainly associated within the high-vacuum range, down to 1×10 mbar (1×10 Pa), diffusion pumps today can produce pressures approaching 1×10 mbar (1×10 Pa) when properly used with modern fluids and accessories. The features that make the diffusion pump attractive for high and ultra-high vacuum use are its high pumping speed for all gases and low cost per unit pumping speed when compared with other types of pump used in the same vacuum range. Diffusion pumps cannot discharge directly into the atmosphere, so a mechanical forepump is typically used to maintain an outlet pressure around 0.1 mbar (10 Pa).
The oil diffusion pump is operated with an oil of low vapor pressure. The high speed jet is generated by boiling the fluid and directing the vapor through a jet assembly. Note that the oil is gaseous when entering the nozzles. Within the nozzles, the flow changes from laminar to supersonic and molecular. Often, several jets are used in series to enhance the pumping action. The outside of the diffusion pump is cooled using either air flow, water lines or a water-filled jacket. As the vapor jet hits the outer cooled shell of the diffusion pump, the working fluid condenses and is recovered and directed back to the boiler. The pumped gases continue flowing to the base of the pump at increased pressure, flowing out through the diffusion pump outlet, where they are compressed to ambient pressure by the secondary mechanical forepump and exhausted.
Unlike turbomolecular pumps and cryopumps, diffusion pumps have no moving parts and as a result are quite durable and reliable. They can function over pressure ranges of 1×10 to 1×10 mbar (1×10 to 1 Pa). They are driven only by convection and thus have a very low energy efficiency.
One major disadvantage of diffusion pumps is the tendency to backstream oil into the vacuum chamber. This oil can contaminate surfaces inside the chamber or upon contact with hot filaments or electrical discharges may result in carbonaceous or siliceous deposits. Due to backstreaming, oil diffusion pumps are not suitable for use with highly sensitive analytical equipment or other applications which require an extremely clean vacuum environment, but mercury diffusion pumps may be in the case of ultra high vacuum chambers used for metal deposition. Often cold traps and baffles are used to minimize backstreaming, although this results in some loss of pumping speed.
The oil of a diffusion pump cannot be exposed to the atmosphere when hot. If this occurs, the oil will oxidise and has to be replaced. If a fire occurs, the smoke and residue may contaminate other parts of the system.
The least expensive diffusion pump oils are based on hydrocarbons which have been purified by double-distillation. Compared with the other fluids, they have higher vapor pressure, so are usually limited to a pressure of 1×10 Torr (1.3×10 Pa). They are also the most likely to burn or explode if exposed to oxidizers.
The most common silicone oils used in diffusion pumps are trisiloxanes, which contain the chemical group Si-O-Si-O-Si, to which various phenyl groups or methyl groups are attached. These are available as the so called 702 and 703 blends, which were formerly manufactured by Dow Corning. These can be further separated into 704 and 705 oils, which are made up of the isomers of tetraphenyl tetramethyl trisiloxane and pentaphenyl trimethyl trisiloxane respectively.
For pumping reactive species, usually a polyphenyl ether based oil is used. These oils are the most chemical and heat resistant type of diffusion pump oil.
The steam ejector is a popular form of pump for vacuum distillation and freeze-drying. A jet of steam entrains the vapour that must be removed from the vacuum chamber. Steam ejectors can have single or multiple stages, with and without condensers in between the stages. While both steam ejectors and diffusion pumps use jets of vapor to entrain gas, they work on fundamentally different principles - steam ejectors rely on viscous flow and mixing to pump gas, whereas diffusion pumps use molecular diffusion. This has several consequences. In diffusion pumps, the inlet pressure can be much lower than the static pressure of jet, whereas in steam ejectors the two pressures are about the same. Also, diffusion pumps are capable of much higher compression ratios, and cannot discharge directly to atmosphere. | [
{
"paragraph_id": 0,
"text": "Diffusion pumps use a high speed jet of vapor to direct gas molecules in the pump throat down into the bottom of the pump and out the exhaust. They were the first type of high vacuum pumps operating in the regime of free molecular flow, where the movement of the gas molecules can be better understood as diffusion than by conventional fluid dynamics. Invented in 1915 by Wolfgang Gaede, he named it a diffusion pump since his design was based on the finding that gas cannot diffuse against the vapor stream, but will be carried with it to the exhaust. However, the principle of operation might be more precisely described as gas-jet pump, since diffusion also plays a role in other types of high vacuum pumps. In modern textbooks, the diffusion pump is categorized as a momentum transfer pump.",
"title": ""
},
{
"paragraph_id": 1,
"text": "The diffusion pump is widely used in both industrial and research applications. Most modern diffusion pumps use silicone oil or polyphenyl ethers as the working fluid.",
"title": ""
},
{
"paragraph_id": 2,
"text": "In the late 19th century, most vacuums were created using a Sprengel pump, which had the advantage of being very simple to operate, and capable of achieving quite good vacuum given enough time. Compared to later pumps, however, the pumping speed was very slow and the vapor pressure of the liquid mercury limited the ultimate vacuum.",
"title": "History"
},
{
"paragraph_id": 3,
"text": "Following his invention of the molecular pump, the diffusion pump was invented in 1915 by Wolfgang Gaede, and originally used elemental mercury as the working fluid. After its invention, the design was quickly commercialized by Leybold.",
"title": "History"
},
{
"paragraph_id": 4,
"text": "It was then improved by Irving Langmuir and W. Crawford. Cecil Reginald Burch discovered the possibility of using silicone oil in 1928.",
"title": "History"
},
{
"paragraph_id": 5,
"text": "An oil diffusion pump is used to achieve higher vacuum (lower pressure) than is possible by use of positive displacement pumps alone. Although its use has been mainly associated within the high-vacuum range, down to 1×10 mbar (1×10 Pa), diffusion pumps today can produce pressures approaching 1×10 mbar (1×10 Pa) when properly used with modern fluids and accessories. The features that make the diffusion pump attractive for high and ultra-high vacuum use are its high pumping speed for all gases and low cost per unit pumping speed when compared with other types of pump used in the same vacuum range. Diffusion pumps cannot discharge directly into the atmosphere, so a mechanical forepump is typically used to maintain an outlet pressure around 0.1 mbar (10 Pa).",
"title": "Oil diffusion pumps"
},
{
"paragraph_id": 6,
"text": "The oil diffusion pump is operated with an oil of low vapor pressure. The high speed jet is generated by boiling the fluid and directing the vapor through a jet assembly. Note that the oil is gaseous when entering the nozzles. Within the nozzles, the flow changes from laminar to supersonic and molecular. Often, several jets are used in series to enhance the pumping action. The outside of the diffusion pump is cooled using either air flow, water lines or a water-filled jacket. As the vapor jet hits the outer cooled shell of the diffusion pump, the working fluid condenses and is recovered and directed back to the boiler. The pumped gases continue flowing to the base of the pump at increased pressure, flowing out through the diffusion pump outlet, where they are compressed to ambient pressure by the secondary mechanical forepump and exhausted.",
"title": "Oil diffusion pumps"
},
{
"paragraph_id": 7,
"text": "Unlike turbomolecular pumps and cryopumps, diffusion pumps have no moving parts and as a result are quite durable and reliable. They can function over pressure ranges of 1×10 to 1×10 mbar (1×10 to 1 Pa). They are driven only by convection and thus have a very low energy efficiency.",
"title": "Oil diffusion pumps"
},
{
"paragraph_id": 8,
"text": "One major disadvantage of diffusion pumps is the tendency to backstream oil into the vacuum chamber. This oil can contaminate surfaces inside the chamber or upon contact with hot filaments or electrical discharges may result in carbonaceous or siliceous deposits. Due to backstreaming, oil diffusion pumps are not suitable for use with highly sensitive analytical equipment or other applications which require an extremely clean vacuum environment, but mercury diffusion pumps may be in the case of ultra high vacuum chambers used for metal deposition. Often cold traps and baffles are used to minimize backstreaming, although this results in some loss of pumping speed.",
"title": "Oil diffusion pumps"
},
{
"paragraph_id": 9,
"text": "The oil of a diffusion pump cannot be exposed to the atmosphere when hot. If this occurs, the oil will oxidise and has to be replaced. If a fire occurs, the smoke and residue may contaminate other parts of the system.",
"title": "Oil diffusion pumps"
},
{
"paragraph_id": 10,
"text": "The least expensive diffusion pump oils are based on hydrocarbons which have been purified by double-distillation. Compared with the other fluids, they have higher vapor pressure, so are usually limited to a pressure of 1×10 Torr (1.3×10 Pa). They are also the most likely to burn or explode if exposed to oxidizers.",
"title": "Oil diffusion pumps"
},
{
"paragraph_id": 11,
"text": "The most common silicone oils used in diffusion pumps are trisiloxanes, which contain the chemical group Si-O-Si-O-Si, to which various phenyl groups or methyl groups are attached. These are available as the so called 702 and 703 blends, which were formerly manufactured by Dow Corning. These can be further separated into 704 and 705 oils, which are made up of the isomers of tetraphenyl tetramethyl trisiloxane and pentaphenyl trimethyl trisiloxane respectively.",
"title": "Oil diffusion pumps"
},
{
"paragraph_id": 12,
"text": "For pumping reactive species, usually a polyphenyl ether based oil is used. These oils are the most chemical and heat resistant type of diffusion pump oil.",
"title": "Oil diffusion pumps"
},
{
"paragraph_id": 13,
"text": "The steam ejector is a popular form of pump for vacuum distillation and freeze-drying. A jet of steam entrains the vapour that must be removed from the vacuum chamber. Steam ejectors can have single or multiple stages, with and without condensers in between the stages. While both steam ejectors and diffusion pumps use jets of vapor to entrain gas, they work on fundamentally different principles - steam ejectors rely on viscous flow and mixing to pump gas, whereas diffusion pumps use molecular diffusion. This has several consequences. In diffusion pumps, the inlet pressure can be much lower than the static pressure of jet, whereas in steam ejectors the two pressures are about the same. Also, diffusion pumps are capable of much higher compression ratios, and cannot discharge directly to atmosphere.",
"title": "Steam ejectors"
}
] | Diffusion pumps use a high speed jet of vapor to direct gas molecules in the pump throat down into the bottom of the pump and out the exhaust. They were the first type of high vacuum pumps operating in the regime of free molecular flow, where the movement of the gas molecules can be better understood as diffusion than by conventional fluid dynamics. Invented in 1915 by Wolfgang Gaede, he named it a diffusion pump since his design was based on the finding that gas cannot diffuse against the vapor stream, but will be carried with it to the exhaust. However, the principle of operation might be more precisely described as gas-jet pump, since diffusion also plays a role in other types of high vacuum pumps. In modern textbooks, the diffusion pump is categorized as a momentum transfer pump. The diffusion pump is widely used in both industrial and research applications. Most modern diffusion pumps use silicone oil or polyphenyl ethers as the working fluid. | 2001-08-09T21:22:08Z | 2023-12-10T05:40:45Z | [
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8,299 | Domenico Alberti | Domenico Alberti (c. 1710 – 14 October 1746 (according to other sources: 1740)) was an Italian singer, harpsichordist, and composer.
Alberti was born in Venice and studied music with Antonio Lotti. He wrote operas, songs, and sonatas for keyboard instruments, for which he is best known today. His sonatas frequently employ arpeggiated accompaniment in the left hand in one of several patterns that are now collectively known as Alberti bass. Alberti was one of the earliest composers to use those patterns, but was not the first or only one. The most well-known of these patterns consists of regular broken chords, with the lowest note sounding first, then the highest, then the middle and then the highest again, with the pattern repeated.
Today, Alberti is regarded as a minor composer, and his works are played or recorded only irregularly. However, the Alberti bass was used by many later composers, and it became an important element in much keyboard music of the classical music era.
An example of Alberti bass (Mozart's Piano Sonata, K 545):
In his own lifetime, Alberti was known as a singer, and often used to accompany himself on the harpsichord. In 1736, he served as a page for Pietro Andrea Cappello, the Venetian ambassador to Spain. While at the Spanish court, the famous castrato singer Farinelli heard him sing. Farinelli was said to have been impressed, although Alberti was an amateur.
Alberti's best known pieces are his keyboard sonatas, although even they are very rarely performed. It is thought he wrote around 36 sonatas, of which 14 have survived. They all have two movements, each in binary form.
It is probable that Mozart's first violin sonatas, written at the age of seven, were modeled on Alberti's work. | [
{
"paragraph_id": 0,
"text": "Domenico Alberti (c. 1710 – 14 October 1746 (according to other sources: 1740)) was an Italian singer, harpsichordist, and composer.",
"title": ""
},
{
"paragraph_id": 1,
"text": "Alberti was born in Venice and studied music with Antonio Lotti. He wrote operas, songs, and sonatas for keyboard instruments, for which he is best known today. His sonatas frequently employ arpeggiated accompaniment in the left hand in one of several patterns that are now collectively known as Alberti bass. Alberti was one of the earliest composers to use those patterns, but was not the first or only one. The most well-known of these patterns consists of regular broken chords, with the lowest note sounding first, then the highest, then the middle and then the highest again, with the pattern repeated.",
"title": ""
},
{
"paragraph_id": 2,
"text": "Today, Alberti is regarded as a minor composer, and his works are played or recorded only irregularly. However, the Alberti bass was used by many later composers, and it became an important element in much keyboard music of the classical music era.",
"title": ""
},
{
"paragraph_id": 3,
"text": "An example of Alberti bass (Mozart's Piano Sonata, K 545):",
"title": ""
},
{
"paragraph_id": 4,
"text": "In his own lifetime, Alberti was known as a singer, and often used to accompany himself on the harpsichord. In 1736, he served as a page for Pietro Andrea Cappello, the Venetian ambassador to Spain. While at the Spanish court, the famous castrato singer Farinelli heard him sing. Farinelli was said to have been impressed, although Alberti was an amateur.",
"title": ""
},
{
"paragraph_id": 5,
"text": "Alberti's best known pieces are his keyboard sonatas, although even they are very rarely performed. It is thought he wrote around 36 sonatas, of which 14 have survived. They all have two movements, each in binary form.",
"title": ""
},
{
"paragraph_id": 6,
"text": "It is probable that Mozart's first violin sonatas, written at the age of seven, were modeled on Alberti's work.",
"title": ""
}
] | Domenico Alberti was an Italian singer, harpsichordist, and composer. Alberti was born in Venice and studied music with Antonio Lotti. He wrote operas, songs, and sonatas for keyboard instruments, for which he is best known today. His sonatas frequently employ arpeggiated accompaniment in the left hand in one of several patterns that are now collectively known as Alberti bass. Alberti was one of the earliest composers to use those patterns, but was not the first or only one. The most well-known of these patterns consists of regular broken chords, with the lowest note sounding first, then the highest, then the middle and then the highest again, with the pattern repeated. Today, Alberti is regarded as a minor composer, and his works are played or recorded only irregularly. However, the Alberti bass was used by many later composers, and it became an important element in much keyboard music of the classical music era. An example of Alberti bass: In his own lifetime, Alberti was known as a singer, and often used to accompany himself on the harpsichord. In 1736, he served as a page for Pietro Andrea Cappello, the Venetian ambassador to Spain. While at the Spanish court, the famous castrato singer Farinelli heard him sing. Farinelli was said to have been impressed, although Alberti was an amateur. Alberti's best known pieces are his keyboard sonatas, although even they are very rarely performed. It is thought he wrote around 36 sonatas, of which 14 have survived. They all have two movements, each in binary form. It is probable that Mozart's first violin sonatas, written at the age of seven, were modeled on Alberti's work. | 2022-11-14T07:01:56Z | [
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|
8,300 | Doris Day | Doris Day (born Doris Mary Anne Kappelhoff; April 3, 1922 – May 13, 2019) was an American actress and singer. She began her career as a big band singer in 1939, achieving commercial success in 1945 with two No. 1 recordings, "Sentimental Journey" and "My Dreams Are Getting Better All the Time" with Les Brown and His Band of Renown. She left Brown to embark on a solo career and recorded more than 650 songs from 1947 to 1967.
Day was one of the greatest Hollywood film stars of the 1950s and 1960s. Her film career began with Romance on the High Seas (1948). She starred in films of many genres, including musicals, comedies, dramas and thrillers. She played the title role in Calamity Jane (1953) and starred in Alfred Hitchcock's The Man Who Knew Too Much (1956) with James Stewart. Some of her best-known films are those in which she costarred with Rock Hudson, including Pillow Talk (1959), for which she was nominated for the Academy Award for Best Actress. She also worked with James Garner on both Move Over, Darling (1963) and The Thrill of It All (1963) and starred alongside Clark Gable, Cary Grant, James Cagney, David Niven, Ginger Rogers, Jack Lemmon, Frank Sinatra, Kirk Douglas, Lauren Bacall, James Garner and Rod Taylor in various films. After ending her film career in 1968, only briefly removed from the height of her popularity, she starred in her own television sitcom The Doris Day Show (1968–1973).
In 1989, Day was awarded the Golden Globe and the Cecil B. DeMille Award for Lifetime Achievement in Motion Pictures. In 2004, she was awarded the Presidential Medal of Freedom. In 2008, she received the Grammy Lifetime Achievement Award as well as a Legend Award from the Society of Singers. In 2011, she was awarded the Los Angeles Film Critics Association's Career Achievement Award. In 2011, Day released her 29th studio album, My Heart, which contained new material and became a UK Top 10 album. As of 2020, she was one of eight recording artists to have been the top box-office earner in the United States four times.
Day was born Doris Mary Anne Kappelhoff (named after actress Doris Kenyon) on April 3, 1922, in Cincinnati, Ohio, the daughter of German-American parents Alma Sophia (née Welz; 1895–1976) and William Joseph Kappelhoff (1892–1967). Her mother was a homemaker, and her father was a music teacher and choirmaster. Her paternal grandfather Franz Joseph Wilhelm Kappelhoff immigrated to the United States in 1875 and settled within the large German community in Cincinnati. For most of her life, Day stated that she was born in 1924, but on the occasion of her 95th birthday, the Associated Press found her birth certificate that showed a 1922 date of birth.
Day had two older brothers: Richard (1917–1919), who died before her birth, and Paul (1919–1957). Her father's infidelity caused her parents to separate in 1932 when she was 10. She developed an early interest in dance, and in the mid-1930s formed a dance duo with Jerry Doherty that performed in nationwide competitions. On October 13, 1937, while Day was riding with friends, their car collided with a freight train, and she broke her right leg, curtailing her prospects as a professional dancer.
While recovering from her car accident, Day sang along with the radio and discovered her singing talent. She later said: "During this long, boring period, I used to while away a lot of time listening to the radio, sometimes singing along with the likes of Benny Goodman, Duke Ellington, Tommy Dorsey, and Glenn Miller. But the one radio voice I listened to above others belonged to Ella Fitzgerald. There was a quality to her voice that fascinated me, and I'd sing along with her, trying to catch the subtle ways she shaded her voice, the casual yet clean way she sang the words."
Day's mother Alma arranged for Doris to receive singing lessons from Grace Raine. After three lessons, Raine told Alma that Day had "tremendous potential" and gave her three lessons per week for the price of one. Years later, Day said that Raine had a greater effect on her singing style and career than had anyone else.
During the eight months when she was receiving singing lessons, Day secured her first professional jobs as a vocalist on the WLW radio program Carlin's Carnival and in a local restaurant, Charlie Yee's Shanghai Inn. During her radio performances, she first caught the attention of Barney Rapp, who was seeking a female vocalist and asked her to audition for the job. According to Rapp, he had auditioned about 200 other singers.
In 1939, Rapp suggested the stage name Doris Day because the Kappelhoff surname was too long for marquees and he admired her rendition of the song "Day After Day". After working with Rapp, Day worked with bandleaders Jimmy James, Bob Crosby and Les Brown. In 1941, Day appeared as a singer in three Soundies with the Les Brown band.
While working with Brown, Day recorded her first hit recording, "Sentimental Journey", released in early 1945. It soon became an anthem for World War II servicemen. The song continues to be associated with Day, and she rerecorded it on several occasions, including a version for her 1971 television special. During 1945–46, Day (as vocalist with the Les Brown Band) had six other top ten hits on the Billboard chart: "My Dreams Are Getting Better All the Time", "'Tain't Me", "Till the End of Time", "You Won't Be Satisfied (Until You Break My Heart)", "The Whole World Is Singing My Song" and "I Got the Sun in the Mornin'". Les Brown said, "As a singer Doris belongs in the company of Bing Crosby and Frank Sinatra."
While singing with the Les Brown band and for nearly two years on Bob Hope's weekly radio program, Day toured extensively across the United States.
Her performance of the song "Embraceable You" impressed songwriter Jule Styne and his partner Sammy Cahn, and they recommended her for a role in Romance on the High Seas (1948). Day was cast for the role after auditioning for director Michael Curtiz. She was shocked to receive the offer and admitted to Curtiz that she was a singer without acting experience. but he appreciated her honesty and felt that "her freckles made her look like the All-American Girl."
The film provided her with a No. 2 hit recording as a soloist, "It's Magic", which occurred two months after her first No. 1 hit "Love Somebody", a duet with Buddy Clark. Day recorded "Someone Like You" before the film My Dream Is Yours (1949), which featured the song. In 1950, she collaborated as a singer with the polka musician Frankie Yankovic, and the U.S. servicemen in Korea voted her their favorite star.
Day continued to appear in light musicals such as On Moonlight Bay (1951), By the Light of the Silvery Moon (1953) and Tea For Two (1950) for Warner Bros.
Her most commercially successful film for Warner Bros. was I'll See You in My Dreams (1951), a musical biography of lyricist Gus Kahn that broke box-office records of 20 years. It was Day's fourth film directed by Curtiz. She appeared as the title character in the comedic western-themed musical Calamity Jane (1953). A song from the film, "Secret Love", won the Academy Award for Best Original Song and became Day's fourth No. 1 hit single in the United States.
Between 1950 and 1953, the albums from six of her film musicals charted in the Top 10, including three that reached No. 1. After filming Lucky Me (1954) with Bob Cummings and Young at Heart (1955) with Frank Sinatra, Day elected to not renew her contract with Warner Brothers.
During this period, Day also had her own radio program, The Doris Day Show. It was broadcast on CBS in 1952–1953.
Primarily recognized as a musical-comedy actress, Day began to accept more dramatic roles in order to broaden her range. Her dramatic star turn as singer Ruth Etting in Love Me or Leave Me (1955), with top billing above James Cagney, received critical and commercial success, becoming Day's greatest film success to that point. Cagney said that she had "the ability to project the simple, direct statement of a simple, direct idea without cluttering it," comparing her performance to that of Laurette Taylor in the Broadway production The Glass Menagerie (1945). Day felt that it was her best film performance. The film's producer Joe Pasternak said, "I was stunned that Doris did not get an Oscar nomination." The film's soundtrack album became a No. 1 hit.
Day starred in Alfred Hitchcock's suspense film The Man Who Knew Too Much (1956 film) opposite James Stewart. She sang two songs in the film, "Que Sera, Sera (Whatever Will Be, Will Be)", which won an Academy Award for Best Original Song, and "We'll Love Again". The film was Day's 10th to reach the top 10 at the box office. She played the title role in the film noir thriller Julie (1956) with Louis Jourdan.
After three successive dramatic films, Day returned to her musical/comedic roots in The Pajama Game (1957) with John Raitt, based on the Broadway play of the same name. She appeared in the Paramount comedy Teacher's Pet (1958) alongside Clark Gable and Gig Young. She costarred with Richard Widmark and Gig Young in the romantic comedy film The Tunnel of Love (1958) and with Jack Lemmon in It Happened to Jane (1959).
Billboard's annual nationwide poll of disc jockeys had ranked Day as the No. 1 female vocalist nine times in ten years (1949 through 1958), but her success and popularity as a singer was now being overshadowed by her box-office appeal.
In 1959, Day entered her most successful phase as a film actress with a series of romantic comedies beginning with Pillow Talk (1959), costarring Rock Hudson, who became a lifelong friend, and Tony Randall. Day received a nomination for an Academy Award for Best Actress, her only career Oscar nomination. Day, Hudson and Randall appeared in two more films together, Lover Come Back (1961) and Send Me No Flowers (1964).
Along with David Niven and Janis Paige, Day starred in Please Don't Eat the Daisies (1960) and with Cary Grant in the comedy That Touch of Mink (1962). During 1960 and the 1962-1964 period, she ranked No. 1 at the box office, the second woman to be No. 1 four times, an accomplishment equaled by no other actress except Shirley Temple. She set a record that has yet to be matched by receiving seven consecutive Laurel Awards as the top female box-office star.
Day teamed with James Garner starting with The Thrill of It All, followed by Move Over, Darling (both 1963). The film's theme song "Move Over Darling", cowritten by her son, reached No. 8 in the UK. Between these comedic film appearances, Day costarred with Rex Harrison in the thriller Midnight Lace (1960), an update of the stage thriller Gaslight.
Day's next film Do Not Disturb (1965) was popular with audiences, but her popularity soon waned. By the late 1960s, in the period of the emerging sexual revolution, some critics and comics dubbed Day "The World's Oldest Virgin," and she slipped from the list of top box-office stars, last appearing in the top ten with the hit film The Glass Bottom Boat (1966). Among the roles that she declined was that of Mrs. Robinson in The Graduate, a role that eventually went to Anne Bancroft. In her memoirs, Day said that she had rejected the part on moral grounds, finding the script "vulgar and offensive."
Day starred in the Western film The Ballad of Josie in 1967. That same year, Day recorded The Love Album, although it was not released until 1994. In 1968, she starred in the comedy film Where Were You When the Lights Went Out? about the Northeast blackout of November 9, 1965. Her final feature, the comedy With Six You Get Eggroll, was released in 1968.
From 1959 to 1970, Day received nine Laurel Award nominations (and won four times) for best female performance in eight comedies and one drama. From 1959 through 1969, she received six Golden Globe nominations for best female performance in three comedies, one drama (Midnight Lace), one musical (Jumbo) and her television series.
After her third husband Martin Melcher died on April 20, 1968, Day was shocked to discover that Melcher and his business partner and advisor Jerome Bernard Rosenthal had squandered her earnings, leaving her deeply in debt. Rosenthal had been her attorney since 1949 when he had represented her in her uncontested divorce action against her second husband, saxophonist George W. Weidler. Day filed suit against Rosenthal in February 1969 and won a successful decision in 1974, but she did not receive compensation until a settlement was reached in 1979.
Day also learned to her displeasure that Melcher had committed her to a television series that became The Doris Day Show.
It was awful. I was really, really not very well when Marty [Melcher] passed away, and the thought of going into TV was overpowering. But he'd signed me up for a series. And then my son Terry [Melcher] took me walking in Beverly Hills and explained that it wasn't nearly the end of it. I had also been signed up for a bunch of TV specials, all without anyone ever asking me.
Day hated the idea of performing on television but felt obligated to forge ahead with the series. The first episode of The Doris Day Show aired on September 24, 1968, and featured a rerecorded version of "Que Sera, Sera" as its theme song. Day persevered with the show, needing to work to repay her debts, but only after CBS ceded creative control to her and her son. The show enjoyed a successful five-year run, although it may be best remembered for its abrupt season-to-season changes in casting and premise.
After the end of the television show's run in 1973, Day largely retired from acting but completed two television specials, The Doris Mary Anne Kappelhoff Special (1971) and Doris Day Today (1975), and she was a guest on various shows in the 1970s.
In the 1985–86 season, Day hosted her own television talk show, Doris Day's Best Friends, on the Christian Broadcasting Network (CBN). The network canceled the show after 26 episodes despite the worldwide publicity that it had received. One episode featured Rock Hudson, who was showing the first public symptoms of AIDS, including severe weight loss and fatigue. He died from the disease later that year. Day later said, "He was very sick. But I just brushed that off and I came out and put my arms around him and said, 'Am I glad to see you'."
In October 1985, the Supreme Court of California rejected Rosenthal's appeal of the multimillion-dollar judgment awarded to Day in her suit against him for legal malpractice and upheld the conclusions of a trial court and an appeals court that Rosenthal had acted improperly. In April 1986, the U.S. Supreme Court refused to review the lower court's judgment. In June 1987, Rosenthal filed a $30 million lawsuit against lawyers whom he claimed had cheated him out of millions of dollars in real-estate investments. He named Day as a codefendant, describing her as an "unwilling, involuntary plaintiff whose consent cannot be obtained." Rosenthal claimed that much of the money that Day had lost was the result of the unwise advice of other attorneys who had suggested that she sell three hotels at a loss, as well as some oil leases in Kentucky and Ohio. He claimed that he had made the investments under a long-term plan and did not intend to sell them until they appreciated in value. Two of the hotels sold in 1970 for about $7 million, and their estimated worth in 1986 was $50 million.
Terry Melcher stated that his father's premature death saved Day from financial ruin. It was not known whether Martin Melcher had himself been duped by Rosenthal, and Day stated publicly that she believed him to be innocent of any deliberate wrongdoing, stating that he "simply trusted the wrong person." Author David Kaufman asserts that Day's former costar Louis Jourdan, maintained that Day disliked her husband, but Day's public statements regarding Melcher appear to contradict that assertion.
Day was scheduled to present, along with Patrick Swayze and Marvin Hamlisch, the award for Best Original Score Oscar at the 61st Academy Awards in March 1989, but she suffered a deep leg cut from a sprinkler and was unable to attend.
Day was inducted into the Ohio Women's Hall of Fame in 1981 and received the Cecil B. DeMille Award for career achievement in 1989. In 1994, Day's Greatest Hits album entered the British charts. Her cover of "Perhaps, Perhaps, Perhaps" was included in the soundtrack of the Australian film Strictly Ballroom.
Day participated in celebrations of her birthday with an annual Doris Day music marathon.
She declined tribute offers from the American Film Institute and the Kennedy Center Honors because they both require that recipients attend in person. In 2004, she was awarded the Presidential Medal of Freedom by President George W. Bush for her achievements in the entertainment industry and for her work on behalf of animals. President Bush stated:
In the years since, she has kept her fans and shown the breadth of her talent in television and the movies. She starred on screen with leading men from Jimmy Stewart to Ronald Reagan, from Rock Hudson to James Garner. It was a good day for America when Doris Marianne von Kappelhoff (sic) of Evanston, Ohio decided to become an entertainer. It was a good day for our fellow creatures when she gave her good heart to the cause of animal welfare. Doris Day is one of the greats, and America will always love its sweetheart.
Columnist Liz Smith and film critic Rex Reed mounted vigorous campaigns to gather support for an Academy Honorary Award for Day. According to The Hollywood Reporter, the academy had offered her the honorary Oscar multiple times, but she declined as she saw the film industry as a part of her past life. Day received a Grammy for Lifetime Achievement in Music in 2008, albeit again in absentia.
Day received Grammy Hall of Fame Awards in 1998, 1999 and 2012 for her recordings of "Sentimental Journey", "Secret Love" and "Que Sera, Sera", respectively. She was inducted into the Hit Parade Hall of Fame in 2007, and in 2010 received the first Legend Award presented by the Society of Singers.
At the age of 89, Day released My Heart in the United Kingdom on September 5, 2011, her first new album since the 1994 release of The Love Album, which had been recorded in 1967. The album is a compilation of previously unreleased recordings produced by Day's son Terry Melcher. Tracks include the 1970s Joe Cocker hit "You Are So Beautiful", the Beach Boys' "Disney Girls" and jazz standards such as "My Buddy", which Day originally sang in the film I'll See You in My Dreams (1951).
In the U.S., the album reached No. 12 on Amazon's bestseller list and helped raise funds for the Doris Day Animal League. Day became the oldest artist to score a UK Top 10 with an album featuring new material.
In January 2012, the Los Angeles Film Critics Association presented Day with a Lifetime Achievement Award.
In April 2014, Day made an unexpected public appearance to attend the annual Doris Day Animal Foundation benefit.
Clint Eastwood offered Day a role in a film that he was planning to direct in 2015, but she eventually declined.
Day granted ABC a telephone interview on her birthday in 2016 that was accompanied by photos of her life and career.
During the filming of The Man Who Knew Too Much, Day observed the mistreatment of animals in a marketplace scene and was inspired to act against animal abuse. She was so appalled at the conditions with which the animals used in filming were kept that she refused to work unless they received sufficient food and proper care. The production company erected feeding stations for the animals and fed them every day before Day would agree to return to work.
In 1971, she cofounded Actors and Others for Animals and appeared in a series of newspaper advertisements denouncing the wearing of fur along with Mary Tyler Moore, Angie Dickinson and Jayne Meadows.
In 1978, Day founded the Doris Day Pet Foundation, now the Doris Day Animal Foundation (DDAF). An independent nonprofit 501(c)(3) grant-giving public charity, DDAF funds other nonprofit causes that promote animal welfare.
To complement the Doris Day Animal Foundation, Day formed the Doris Day Animal League (DDAL) in 1987, a national nonprofit citizens' lobbying organization on behalf of animals. Day actively lobbied the United States Congress in support of legislation designed to safeguard animal welfare on a number of occasions, and in 1995 she originated the annual World Spay Day. The DDAL merged into the Humane Society of the United States (HSUS) in 2006.
The Doris Day Horse Rescue and Adoption Center, which helps abused and neglected horses, opened in 2011 in Murchison, Texas on the grounds of an animal sanctuary started by Day's late friend, author Cleveland Amory. Day contributed $250,000 toward the founding of the center.
A posthumous auction of 1,100 of Day's possessions in April 2020 generated $3 million for the Doris Day Animal Foundation.
Doris Day actively engaged in HIV/AIDS awareness for many years. Her commitment was primarily focused on raising awareness and fundraising for HIV/AIDS research. She co-organized several fundraising events for HIV/AIDS-related charities and provided financial contributions to research and support programs for individuals affected by the disease. In 2011, the Canadian magazine Gay Globe paid tribute to Doris Day by featuring her on the cover of their #79 edition.
Day's only child was music producer and songwriter Terry Melcher, who had a hit in the 1960s with "Hey Little Cobra" under the name the Rip Chords before becoming a successful producer whose acts included the Byrds, Paul Revere & the Raiders and the Beach Boys. In the late 1960s, Melcher became acquainted with Charles Manson and nearly signed him to a record deal. In August 1969, the Tate murders, orchestrated by Manson, were committed at the Benedict Canyon house that Melcher had formerly occupied. Melcher died of melanoma in November 2004.
Since the 1980s, Day owned a hotel in Carmel-by-the-Sea called the Cypress Inn, an early pet–friendly hotel that was featured in Architectural Digest in 1999.
Day was married four times. From April 1941 to February 1943, she was married to trombonist Al Jorden (1917–1967), whom she met in Barney Rapp's band. Jorden, a violent schizophrenic, committed suicide. When Day became pregnant and refused to have an abortion, he beat her in an attempt to force a miscarriage. Their son was born Terrence Paul Jorden in 1942, and he adopted the surname of Melcher when he was adopted by Day's third husband.
Her second marriage was to George William Weidler (1926–1989), a saxophonist and brother of actress Virginia Weidler, from March 30, 1946, to May 31, 1949. Weidler and Day met again several years later during a brief reconciliation and he introduced her to Christian Science.
Day married American film producer Martin Melcher (1915–1968), who produced many of her films, on April 3, 1951, her 29th birthday, and the marriage lasted until he died in April 1968. Melcher adopted Day's son Terry. As Day and Melcher were both Christian Scientists, she refused to visit a doctor for some time after experiencing symptoms that might have suggested cancer. Following Melcher's death, Day separated from the Church of Christ, Scientist and grew close to charismatic Protestants such as Kathryn Kuhlman, although she never lost interest in Christian Science teaching and practice.
Day's fourth marriage was to Barry Comden (1935–2009) from April 14, 1976, until April 2, 1982. He was the maître d'hôtel at one of Day's favorite restaurants. He knew of her great love of dogs and endeared himself to her by giving her a bag of meat scraps and bones as she left the restaurant. He later complained that Day cared more for her "animal friends" than for him.
After her retirement from films, Day lived in Carmel-by-the-Sea, California. She had many pets and adopted stray animals. She was a lifelong Republican.
In a rare interview with The Hollywood Reporter on April 4, 2019, the day after her 97th birthday, Day talked about her work on the Doris Day Animal Foundation, founded in 1978. Asked to name the favorite of her films, she answered with Calamity Jane: "I was such a tomboy growing up, and she was such a fun character to play. Of course, the music was wonderful, too—'Secret Love,' especially, is such a beautiful song."
To commemorate her birthday, Day's fans gathered in late March each year for a three-day party in Carmel-by-the-Sea, California. The event was also a fundraiser for her animal foundation. During the 2019 event, there was a special screening of her film Pillow Talk (1959) to celebrate its 60th anniversary. Speaking about the film, Day stated that she "had such fun working with my pal, Rock. We laughed our way through three films we made together and remained great friends. I miss him."
Day died of pneumonia at her home in Carmel Valley, California, on May 13, 2019, at the age of 97. Her death was announced by the Doris Day Animal Foundation. As requested by Day, the foundation announced that there would be no funeral services, grave marker or other public memorials.
Source | [
{
"paragraph_id": 0,
"text": "Doris Day (born Doris Mary Anne Kappelhoff; April 3, 1922 – May 13, 2019) was an American actress and singer. She began her career as a big band singer in 1939, achieving commercial success in 1945 with two No. 1 recordings, \"Sentimental Journey\" and \"My Dreams Are Getting Better All the Time\" with Les Brown and His Band of Renown. She left Brown to embark on a solo career and recorded more than 650 songs from 1947 to 1967.",
"title": ""
},
{
"paragraph_id": 1,
"text": "Day was one of the greatest Hollywood film stars of the 1950s and 1960s. Her film career began with Romance on the High Seas (1948). She starred in films of many genres, including musicals, comedies, dramas and thrillers. She played the title role in Calamity Jane (1953) and starred in Alfred Hitchcock's The Man Who Knew Too Much (1956) with James Stewart. Some of her best-known films are those in which she costarred with Rock Hudson, including Pillow Talk (1959), for which she was nominated for the Academy Award for Best Actress. She also worked with James Garner on both Move Over, Darling (1963) and The Thrill of It All (1963) and starred alongside Clark Gable, Cary Grant, James Cagney, David Niven, Ginger Rogers, Jack Lemmon, Frank Sinatra, Kirk Douglas, Lauren Bacall, James Garner and Rod Taylor in various films. After ending her film career in 1968, only briefly removed from the height of her popularity, she starred in her own television sitcom The Doris Day Show (1968–1973).",
"title": ""
},
{
"paragraph_id": 2,
"text": "In 1989, Day was awarded the Golden Globe and the Cecil B. DeMille Award for Lifetime Achievement in Motion Pictures. In 2004, she was awarded the Presidential Medal of Freedom. In 2008, she received the Grammy Lifetime Achievement Award as well as a Legend Award from the Society of Singers. In 2011, she was awarded the Los Angeles Film Critics Association's Career Achievement Award. In 2011, Day released her 29th studio album, My Heart, which contained new material and became a UK Top 10 album. As of 2020, she was one of eight recording artists to have been the top box-office earner in the United States four times.",
"title": ""
},
{
"paragraph_id": 3,
"text": "Day was born Doris Mary Anne Kappelhoff (named after actress Doris Kenyon) on April 3, 1922, in Cincinnati, Ohio, the daughter of German-American parents Alma Sophia (née Welz; 1895–1976) and William Joseph Kappelhoff (1892–1967). Her mother was a homemaker, and her father was a music teacher and choirmaster. Her paternal grandfather Franz Joseph Wilhelm Kappelhoff immigrated to the United States in 1875 and settled within the large German community in Cincinnati. For most of her life, Day stated that she was born in 1924, but on the occasion of her 95th birthday, the Associated Press found her birth certificate that showed a 1922 date of birth.",
"title": "Early life"
},
{
"paragraph_id": 4,
"text": "Day had two older brothers: Richard (1917–1919), who died before her birth, and Paul (1919–1957). Her father's infidelity caused her parents to separate in 1932 when she was 10. She developed an early interest in dance, and in the mid-1930s formed a dance duo with Jerry Doherty that performed in nationwide competitions. On October 13, 1937, while Day was riding with friends, their car collided with a freight train, and she broke her right leg, curtailing her prospects as a professional dancer.",
"title": "Early life"
},
{
"paragraph_id": 5,
"text": "While recovering from her car accident, Day sang along with the radio and discovered her singing talent. She later said: \"During this long, boring period, I used to while away a lot of time listening to the radio, sometimes singing along with the likes of Benny Goodman, Duke Ellington, Tommy Dorsey, and Glenn Miller. But the one radio voice I listened to above others belonged to Ella Fitzgerald. There was a quality to her voice that fascinated me, and I'd sing along with her, trying to catch the subtle ways she shaded her voice, the casual yet clean way she sang the words.\"",
"title": "Career"
},
{
"paragraph_id": 6,
"text": "Day's mother Alma arranged for Doris to receive singing lessons from Grace Raine. After three lessons, Raine told Alma that Day had \"tremendous potential\" and gave her three lessons per week for the price of one. Years later, Day said that Raine had a greater effect on her singing style and career than had anyone else.",
"title": "Career"
},
{
"paragraph_id": 7,
"text": "During the eight months when she was receiving singing lessons, Day secured her first professional jobs as a vocalist on the WLW radio program Carlin's Carnival and in a local restaurant, Charlie Yee's Shanghai Inn. During her radio performances, she first caught the attention of Barney Rapp, who was seeking a female vocalist and asked her to audition for the job. According to Rapp, he had auditioned about 200 other singers.",
"title": "Career"
},
{
"paragraph_id": 8,
"text": "In 1939, Rapp suggested the stage name Doris Day because the Kappelhoff surname was too long for marquees and he admired her rendition of the song \"Day After Day\". After working with Rapp, Day worked with bandleaders Jimmy James, Bob Crosby and Les Brown. In 1941, Day appeared as a singer in three Soundies with the Les Brown band.",
"title": "Career"
},
{
"paragraph_id": 9,
"text": "While working with Brown, Day recorded her first hit recording, \"Sentimental Journey\", released in early 1945. It soon became an anthem for World War II servicemen. The song continues to be associated with Day, and she rerecorded it on several occasions, including a version for her 1971 television special. During 1945–46, Day (as vocalist with the Les Brown Band) had six other top ten hits on the Billboard chart: \"My Dreams Are Getting Better All the Time\", \"'Tain't Me\", \"Till the End of Time\", \"You Won't Be Satisfied (Until You Break My Heart)\", \"The Whole World Is Singing My Song\" and \"I Got the Sun in the Mornin'\". Les Brown said, \"As a singer Doris belongs in the company of Bing Crosby and Frank Sinatra.\"",
"title": "Career"
},
{
"paragraph_id": 10,
"text": "While singing with the Les Brown band and for nearly two years on Bob Hope's weekly radio program, Day toured extensively across the United States.",
"title": "Career"
},
{
"paragraph_id": 11,
"text": "Her performance of the song \"Embraceable You\" impressed songwriter Jule Styne and his partner Sammy Cahn, and they recommended her for a role in Romance on the High Seas (1948). Day was cast for the role after auditioning for director Michael Curtiz. She was shocked to receive the offer and admitted to Curtiz that she was a singer without acting experience. but he appreciated her honesty and felt that \"her freckles made her look like the All-American Girl.\"",
"title": "Career"
},
{
"paragraph_id": 12,
"text": "The film provided her with a No. 2 hit recording as a soloist, \"It's Magic\", which occurred two months after her first No. 1 hit \"Love Somebody\", a duet with Buddy Clark. Day recorded \"Someone Like You\" before the film My Dream Is Yours (1949), which featured the song. In 1950, she collaborated as a singer with the polka musician Frankie Yankovic, and the U.S. servicemen in Korea voted her their favorite star.",
"title": "Career"
},
{
"paragraph_id": 13,
"text": "Day continued to appear in light musicals such as On Moonlight Bay (1951), By the Light of the Silvery Moon (1953) and Tea For Two (1950) for Warner Bros.",
"title": "Career"
},
{
"paragraph_id": 14,
"text": "Her most commercially successful film for Warner Bros. was I'll See You in My Dreams (1951), a musical biography of lyricist Gus Kahn that broke box-office records of 20 years. It was Day's fourth film directed by Curtiz. She appeared as the title character in the comedic western-themed musical Calamity Jane (1953). A song from the film, \"Secret Love\", won the Academy Award for Best Original Song and became Day's fourth No. 1 hit single in the United States.",
"title": "Career"
},
{
"paragraph_id": 15,
"text": "Between 1950 and 1953, the albums from six of her film musicals charted in the Top 10, including three that reached No. 1. After filming Lucky Me (1954) with Bob Cummings and Young at Heart (1955) with Frank Sinatra, Day elected to not renew her contract with Warner Brothers.",
"title": "Career"
},
{
"paragraph_id": 16,
"text": "During this period, Day also had her own radio program, The Doris Day Show. It was broadcast on CBS in 1952–1953.",
"title": "Career"
},
{
"paragraph_id": 17,
"text": "Primarily recognized as a musical-comedy actress, Day began to accept more dramatic roles in order to broaden her range. Her dramatic star turn as singer Ruth Etting in Love Me or Leave Me (1955), with top billing above James Cagney, received critical and commercial success, becoming Day's greatest film success to that point. Cagney said that she had \"the ability to project the simple, direct statement of a simple, direct idea without cluttering it,\" comparing her performance to that of Laurette Taylor in the Broadway production The Glass Menagerie (1945). Day felt that it was her best film performance. The film's producer Joe Pasternak said, \"I was stunned that Doris did not get an Oscar nomination.\" The film's soundtrack album became a No. 1 hit.",
"title": "Career"
},
{
"paragraph_id": 18,
"text": "Day starred in Alfred Hitchcock's suspense film The Man Who Knew Too Much (1956 film) opposite James Stewart. She sang two songs in the film, \"Que Sera, Sera (Whatever Will Be, Will Be)\", which won an Academy Award for Best Original Song, and \"We'll Love Again\". The film was Day's 10th to reach the top 10 at the box office. She played the title role in the film noir thriller Julie (1956) with Louis Jourdan.",
"title": "Career"
},
{
"paragraph_id": 19,
"text": "After three successive dramatic films, Day returned to her musical/comedic roots in The Pajama Game (1957) with John Raitt, based on the Broadway play of the same name. She appeared in the Paramount comedy Teacher's Pet (1958) alongside Clark Gable and Gig Young. She costarred with Richard Widmark and Gig Young in the romantic comedy film The Tunnel of Love (1958) and with Jack Lemmon in It Happened to Jane (1959).",
"title": "Career"
},
{
"paragraph_id": 20,
"text": "Billboard's annual nationwide poll of disc jockeys had ranked Day as the No. 1 female vocalist nine times in ten years (1949 through 1958), but her success and popularity as a singer was now being overshadowed by her box-office appeal.",
"title": "Career"
},
{
"paragraph_id": 21,
"text": "In 1959, Day entered her most successful phase as a film actress with a series of romantic comedies beginning with Pillow Talk (1959), costarring Rock Hudson, who became a lifelong friend, and Tony Randall. Day received a nomination for an Academy Award for Best Actress, her only career Oscar nomination. Day, Hudson and Randall appeared in two more films together, Lover Come Back (1961) and Send Me No Flowers (1964).",
"title": "Career"
},
{
"paragraph_id": 22,
"text": "Along with David Niven and Janis Paige, Day starred in Please Don't Eat the Daisies (1960) and with Cary Grant in the comedy That Touch of Mink (1962). During 1960 and the 1962-1964 period, she ranked No. 1 at the box office, the second woman to be No. 1 four times, an accomplishment equaled by no other actress except Shirley Temple. She set a record that has yet to be matched by receiving seven consecutive Laurel Awards as the top female box-office star.",
"title": "Career"
},
{
"paragraph_id": 23,
"text": "Day teamed with James Garner starting with The Thrill of It All, followed by Move Over, Darling (both 1963). The film's theme song \"Move Over Darling\", cowritten by her son, reached No. 8 in the UK. Between these comedic film appearances, Day costarred with Rex Harrison in the thriller Midnight Lace (1960), an update of the stage thriller Gaslight.",
"title": "Career"
},
{
"paragraph_id": 24,
"text": "Day's next film Do Not Disturb (1965) was popular with audiences, but her popularity soon waned. By the late 1960s, in the period of the emerging sexual revolution, some critics and comics dubbed Day \"The World's Oldest Virgin,\" and she slipped from the list of top box-office stars, last appearing in the top ten with the hit film The Glass Bottom Boat (1966). Among the roles that she declined was that of Mrs. Robinson in The Graduate, a role that eventually went to Anne Bancroft. In her memoirs, Day said that she had rejected the part on moral grounds, finding the script \"vulgar and offensive.\"",
"title": "Career"
},
{
"paragraph_id": 25,
"text": "Day starred in the Western film The Ballad of Josie in 1967. That same year, Day recorded The Love Album, although it was not released until 1994. In 1968, she starred in the comedy film Where Were You When the Lights Went Out? about the Northeast blackout of November 9, 1965. Her final feature, the comedy With Six You Get Eggroll, was released in 1968.",
"title": "Career"
},
{
"paragraph_id": 26,
"text": "From 1959 to 1970, Day received nine Laurel Award nominations (and won four times) for best female performance in eight comedies and one drama. From 1959 through 1969, she received six Golden Globe nominations for best female performance in three comedies, one drama (Midnight Lace), one musical (Jumbo) and her television series.",
"title": "Career"
},
{
"paragraph_id": 27,
"text": "After her third husband Martin Melcher died on April 20, 1968, Day was shocked to discover that Melcher and his business partner and advisor Jerome Bernard Rosenthal had squandered her earnings, leaving her deeply in debt. Rosenthal had been her attorney since 1949 when he had represented her in her uncontested divorce action against her second husband, saxophonist George W. Weidler. Day filed suit against Rosenthal in February 1969 and won a successful decision in 1974, but she did not receive compensation until a settlement was reached in 1979.",
"title": "Career"
},
{
"paragraph_id": 28,
"text": "Day also learned to her displeasure that Melcher had committed her to a television series that became The Doris Day Show.",
"title": "Career"
},
{
"paragraph_id": 29,
"text": "It was awful. I was really, really not very well when Marty [Melcher] passed away, and the thought of going into TV was overpowering. But he'd signed me up for a series. And then my son Terry [Melcher] took me walking in Beverly Hills and explained that it wasn't nearly the end of it. I had also been signed up for a bunch of TV specials, all without anyone ever asking me.",
"title": "Career"
},
{
"paragraph_id": 30,
"text": "Day hated the idea of performing on television but felt obligated to forge ahead with the series. The first episode of The Doris Day Show aired on September 24, 1968, and featured a rerecorded version of \"Que Sera, Sera\" as its theme song. Day persevered with the show, needing to work to repay her debts, but only after CBS ceded creative control to her and her son. The show enjoyed a successful five-year run, although it may be best remembered for its abrupt season-to-season changes in casting and premise.",
"title": "Career"
},
{
"paragraph_id": 31,
"text": "After the end of the television show's run in 1973, Day largely retired from acting but completed two television specials, The Doris Mary Anne Kappelhoff Special (1971) and Doris Day Today (1975), and she was a guest on various shows in the 1970s.",
"title": "Career"
},
{
"paragraph_id": 32,
"text": "In the 1985–86 season, Day hosted her own television talk show, Doris Day's Best Friends, on the Christian Broadcasting Network (CBN). The network canceled the show after 26 episodes despite the worldwide publicity that it had received. One episode featured Rock Hudson, who was showing the first public symptoms of AIDS, including severe weight loss and fatigue. He died from the disease later that year. Day later said, \"He was very sick. But I just brushed that off and I came out and put my arms around him and said, 'Am I glad to see you'.\"",
"title": "Career"
},
{
"paragraph_id": 33,
"text": "In October 1985, the Supreme Court of California rejected Rosenthal's appeal of the multimillion-dollar judgment awarded to Day in her suit against him for legal malpractice and upheld the conclusions of a trial court and an appeals court that Rosenthal had acted improperly. In April 1986, the U.S. Supreme Court refused to review the lower court's judgment. In June 1987, Rosenthal filed a $30 million lawsuit against lawyers whom he claimed had cheated him out of millions of dollars in real-estate investments. He named Day as a codefendant, describing her as an \"unwilling, involuntary plaintiff whose consent cannot be obtained.\" Rosenthal claimed that much of the money that Day had lost was the result of the unwise advice of other attorneys who had suggested that she sell three hotels at a loss, as well as some oil leases in Kentucky and Ohio. He claimed that he had made the investments under a long-term plan and did not intend to sell them until they appreciated in value. Two of the hotels sold in 1970 for about $7 million, and their estimated worth in 1986 was $50 million.",
"title": "Career"
},
{
"paragraph_id": 34,
"text": "Terry Melcher stated that his father's premature death saved Day from financial ruin. It was not known whether Martin Melcher had himself been duped by Rosenthal, and Day stated publicly that she believed him to be innocent of any deliberate wrongdoing, stating that he \"simply trusted the wrong person.\" Author David Kaufman asserts that Day's former costar Louis Jourdan, maintained that Day disliked her husband, but Day's public statements regarding Melcher appear to contradict that assertion.",
"title": "Career"
},
{
"paragraph_id": 35,
"text": "Day was scheduled to present, along with Patrick Swayze and Marvin Hamlisch, the award for Best Original Score Oscar at the 61st Academy Awards in March 1989, but she suffered a deep leg cut from a sprinkler and was unable to attend.",
"title": "Career"
},
{
"paragraph_id": 36,
"text": "Day was inducted into the Ohio Women's Hall of Fame in 1981 and received the Cecil B. DeMille Award for career achievement in 1989. In 1994, Day's Greatest Hits album entered the British charts. Her cover of \"Perhaps, Perhaps, Perhaps\" was included in the soundtrack of the Australian film Strictly Ballroom.",
"title": "Career"
},
{
"paragraph_id": 37,
"text": "Day participated in celebrations of her birthday with an annual Doris Day music marathon.",
"title": "Career"
},
{
"paragraph_id": 38,
"text": "She declined tribute offers from the American Film Institute and the Kennedy Center Honors because they both require that recipients attend in person. In 2004, she was awarded the Presidential Medal of Freedom by President George W. Bush for her achievements in the entertainment industry and for her work on behalf of animals. President Bush stated:",
"title": "Career"
},
{
"paragraph_id": 39,
"text": "In the years since, she has kept her fans and shown the breadth of her talent in television and the movies. She starred on screen with leading men from Jimmy Stewart to Ronald Reagan, from Rock Hudson to James Garner. It was a good day for America when Doris Marianne von Kappelhoff (sic) of Evanston, Ohio decided to become an entertainer. It was a good day for our fellow creatures when she gave her good heart to the cause of animal welfare. Doris Day is one of the greats, and America will always love its sweetheart.",
"title": "Career"
},
{
"paragraph_id": 40,
"text": "Columnist Liz Smith and film critic Rex Reed mounted vigorous campaigns to gather support for an Academy Honorary Award for Day. According to The Hollywood Reporter, the academy had offered her the honorary Oscar multiple times, but she declined as she saw the film industry as a part of her past life. Day received a Grammy for Lifetime Achievement in Music in 2008, albeit again in absentia.",
"title": "Career"
},
{
"paragraph_id": 41,
"text": "Day received Grammy Hall of Fame Awards in 1998, 1999 and 2012 for her recordings of \"Sentimental Journey\", \"Secret Love\" and \"Que Sera, Sera\", respectively. She was inducted into the Hit Parade Hall of Fame in 2007, and in 2010 received the first Legend Award presented by the Society of Singers.",
"title": "Career"
},
{
"paragraph_id": 42,
"text": "At the age of 89, Day released My Heart in the United Kingdom on September 5, 2011, her first new album since the 1994 release of The Love Album, which had been recorded in 1967. The album is a compilation of previously unreleased recordings produced by Day's son Terry Melcher. Tracks include the 1970s Joe Cocker hit \"You Are So Beautiful\", the Beach Boys' \"Disney Girls\" and jazz standards such as \"My Buddy\", which Day originally sang in the film I'll See You in My Dreams (1951).",
"title": "Career"
},
{
"paragraph_id": 43,
"text": "In the U.S., the album reached No. 12 on Amazon's bestseller list and helped raise funds for the Doris Day Animal League. Day became the oldest artist to score a UK Top 10 with an album featuring new material.",
"title": "Career"
},
{
"paragraph_id": 44,
"text": "In January 2012, the Los Angeles Film Critics Association presented Day with a Lifetime Achievement Award.",
"title": "Career"
},
{
"paragraph_id": 45,
"text": "In April 2014, Day made an unexpected public appearance to attend the annual Doris Day Animal Foundation benefit.",
"title": "Career"
},
{
"paragraph_id": 46,
"text": "Clint Eastwood offered Day a role in a film that he was planning to direct in 2015, but she eventually declined.",
"title": "Career"
},
{
"paragraph_id": 47,
"text": "Day granted ABC a telephone interview on her birthday in 2016 that was accompanied by photos of her life and career.",
"title": "Career"
},
{
"paragraph_id": 48,
"text": "During the filming of The Man Who Knew Too Much, Day observed the mistreatment of animals in a marketplace scene and was inspired to act against animal abuse. She was so appalled at the conditions with which the animals used in filming were kept that she refused to work unless they received sufficient food and proper care. The production company erected feeding stations for the animals and fed them every day before Day would agree to return to work.",
"title": "Animal-welfare and HIV/AIDS activism"
},
{
"paragraph_id": 49,
"text": "In 1971, she cofounded Actors and Others for Animals and appeared in a series of newspaper advertisements denouncing the wearing of fur along with Mary Tyler Moore, Angie Dickinson and Jayne Meadows.",
"title": "Animal-welfare and HIV/AIDS activism"
},
{
"paragraph_id": 50,
"text": "In 1978, Day founded the Doris Day Pet Foundation, now the Doris Day Animal Foundation (DDAF). An independent nonprofit 501(c)(3) grant-giving public charity, DDAF funds other nonprofit causes that promote animal welfare.",
"title": "Animal-welfare and HIV/AIDS activism"
},
{
"paragraph_id": 51,
"text": "To complement the Doris Day Animal Foundation, Day formed the Doris Day Animal League (DDAL) in 1987, a national nonprofit citizens' lobbying organization on behalf of animals. Day actively lobbied the United States Congress in support of legislation designed to safeguard animal welfare on a number of occasions, and in 1995 she originated the annual World Spay Day. The DDAL merged into the Humane Society of the United States (HSUS) in 2006.",
"title": "Animal-welfare and HIV/AIDS activism"
},
{
"paragraph_id": 52,
"text": "The Doris Day Horse Rescue and Adoption Center, which helps abused and neglected horses, opened in 2011 in Murchison, Texas on the grounds of an animal sanctuary started by Day's late friend, author Cleveland Amory. Day contributed $250,000 toward the founding of the center.",
"title": "Animal-welfare and HIV/AIDS activism"
},
{
"paragraph_id": 53,
"text": "A posthumous auction of 1,100 of Day's possessions in April 2020 generated $3 million for the Doris Day Animal Foundation.",
"title": "Animal-welfare and HIV/AIDS activism"
},
{
"paragraph_id": 54,
"text": "Doris Day actively engaged in HIV/AIDS awareness for many years. Her commitment was primarily focused on raising awareness and fundraising for HIV/AIDS research. She co-organized several fundraising events for HIV/AIDS-related charities and provided financial contributions to research and support programs for individuals affected by the disease. In 2011, the Canadian magazine Gay Globe paid tribute to Doris Day by featuring her on the cover of their #79 edition.",
"title": "Animal-welfare and HIV/AIDS activism"
},
{
"paragraph_id": 55,
"text": "Day's only child was music producer and songwriter Terry Melcher, who had a hit in the 1960s with \"Hey Little Cobra\" under the name the Rip Chords before becoming a successful producer whose acts included the Byrds, Paul Revere & the Raiders and the Beach Boys. In the late 1960s, Melcher became acquainted with Charles Manson and nearly signed him to a record deal. In August 1969, the Tate murders, orchestrated by Manson, were committed at the Benedict Canyon house that Melcher had formerly occupied. Melcher died of melanoma in November 2004.",
"title": "Personal life"
},
{
"paragraph_id": 56,
"text": "Since the 1980s, Day owned a hotel in Carmel-by-the-Sea called the Cypress Inn, an early pet–friendly hotel that was featured in Architectural Digest in 1999.",
"title": "Personal life"
},
{
"paragraph_id": 57,
"text": "Day was married four times. From April 1941 to February 1943, she was married to trombonist Al Jorden (1917–1967), whom she met in Barney Rapp's band. Jorden, a violent schizophrenic, committed suicide. When Day became pregnant and refused to have an abortion, he beat her in an attempt to force a miscarriage. Their son was born Terrence Paul Jorden in 1942, and he adopted the surname of Melcher when he was adopted by Day's third husband.",
"title": "Personal life"
},
{
"paragraph_id": 58,
"text": "Her second marriage was to George William Weidler (1926–1989), a saxophonist and brother of actress Virginia Weidler, from March 30, 1946, to May 31, 1949. Weidler and Day met again several years later during a brief reconciliation and he introduced her to Christian Science.",
"title": "Personal life"
},
{
"paragraph_id": 59,
"text": "Day married American film producer Martin Melcher (1915–1968), who produced many of her films, on April 3, 1951, her 29th birthday, and the marriage lasted until he died in April 1968. Melcher adopted Day's son Terry. As Day and Melcher were both Christian Scientists, she refused to visit a doctor for some time after experiencing symptoms that might have suggested cancer. Following Melcher's death, Day separated from the Church of Christ, Scientist and grew close to charismatic Protestants such as Kathryn Kuhlman, although she never lost interest in Christian Science teaching and practice.",
"title": "Personal life"
},
{
"paragraph_id": 60,
"text": "Day's fourth marriage was to Barry Comden (1935–2009) from April 14, 1976, until April 2, 1982. He was the maître d'hôtel at one of Day's favorite restaurants. He knew of her great love of dogs and endeared himself to her by giving her a bag of meat scraps and bones as she left the restaurant. He later complained that Day cared more for her \"animal friends\" than for him.",
"title": "Personal life"
},
{
"paragraph_id": 61,
"text": "After her retirement from films, Day lived in Carmel-by-the-Sea, California. She had many pets and adopted stray animals. She was a lifelong Republican.",
"title": "Personal life"
},
{
"paragraph_id": 62,
"text": "In a rare interview with The Hollywood Reporter on April 4, 2019, the day after her 97th birthday, Day talked about her work on the Doris Day Animal Foundation, founded in 1978. Asked to name the favorite of her films, she answered with Calamity Jane: \"I was such a tomboy growing up, and she was such a fun character to play. Of course, the music was wonderful, too—'Secret Love,' especially, is such a beautiful song.\"",
"title": "Personal life"
},
{
"paragraph_id": 63,
"text": "To commemorate her birthday, Day's fans gathered in late March each year for a three-day party in Carmel-by-the-Sea, California. The event was also a fundraiser for her animal foundation. During the 2019 event, there was a special screening of her film Pillow Talk (1959) to celebrate its 60th anniversary. Speaking about the film, Day stated that she \"had such fun working with my pal, Rock. We laughed our way through three films we made together and remained great friends. I miss him.\"",
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"text": "Day died of pneumonia at her home in Carmel Valley, California, on May 13, 2019, at the age of 97. Her death was announced by the Doris Day Animal Foundation. As requested by Day, the foundation announced that there would be no funeral services, grave marker or other public memorials.",
"title": "Personal life"
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] | Doris Day was an American actress and singer. She began her career as a big band singer in 1939, achieving commercial success in 1945 with two No. 1 recordings, "Sentimental Journey" and "My Dreams Are Getting Better All the Time" with Les Brown and His Band of Renown. She left Brown to embark on a solo career and recorded more than 650 songs from 1947 to 1967. Day was one of the greatest Hollywood film stars of the 1950s and 1960s. Her film career began with Romance on the High Seas (1948). She starred in films of many genres, including musicals, comedies, dramas and thrillers. She played the title role in Calamity Jane (1953) and starred in Alfred Hitchcock's The Man Who Knew Too Much (1956) with James Stewart. Some of her best-known films are those in which she costarred with Rock Hudson, including Pillow Talk (1959), for which she was nominated for the Academy Award for Best Actress. She also worked with James Garner on both Move Over, Darling (1963) and The Thrill of It All (1963) and starred alongside Clark Gable, Cary Grant, James Cagney, David Niven, Ginger Rogers, Jack Lemmon, Frank Sinatra, Kirk Douglas, Lauren Bacall, James Garner and Rod Taylor in various films. After ending her film career in 1968, only briefly removed from the height of her popularity, she starred in her own television sitcom The Doris Day Show (1968–1973). In 1989, Day was awarded the Golden Globe and the Cecil B. DeMille Award for Lifetime Achievement in Motion Pictures. In 2004, she was awarded the Presidential Medal of Freedom. In 2008, she received the Grammy Lifetime Achievement Award as well as a Legend Award from the Society of Singers. In 2011, she was awarded the Los Angeles Film Critics Association's Career Achievement Award. In 2011, Day released her 29th studio album, My Heart, which contained new material and became a UK Top 10 album. As of 2020, she was one of eight recording artists to have been the top box-office earner in the United States four times. | 2001-08-10T19:55:45Z | 2023-12-29T22:10:40Z | [
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8,301 | Distillation | Distillation, or classical distillation, is the process of separating the components or substances from a liquid mixture by using selective boiling and condensation, usually inside an apparatus known as a still. Dry distillation is the heating of solid materials to produce gaseous products (which may condense into liquids or solids); this may involve chemical changes such as destructive distillation or cracking. Distillation may result in essentially complete separation (resulting in nearly pure components), or it may be a partial separation that increases the concentration of selected components; in either case, the process exploits differences in the relative volatility of the mixture's components. In industrial applications, distillation is a unit operation of practically universal importance, but is a physical separation process, not a chemical reaction. An installation used for distillation, especially of distilled beverages, is a distillery. Distillation includes the following applications:
Early evidence of distillation was found on Akkadian tablets dated c. 1200 BCE describing perfumery operations. The tablets provided textual evidence that an early, primitive form of distillation was known to the Babylonians of ancient Mesopotamia.
Aristotle knew that water condensing from evaporating seawater is fresh:
I have proved by experiment that salt water evaporated forms fresh, and the vapour does not, when it condenses, condense into sea water again.
Letting seawater evaporate and condense into freshwater is not distillation, for distillation involves boiling, but the experiment may have been an important step towards distillation.
Distillation was practiced in the ancient Indian subcontinent, which is evident from baked clay retorts and receivers found at Taxila, Shaikhan Dheri, and Charsadda in Pakistan and Rang Mahal in India dating to the early centuries of the Common Era. Frank Raymond Allchin says these terracotta distill tubes were "made to imitate bamboo". These "Gandhara stills" were only capable of producing very weak liquor, as there was no efficient means of collecting the vapors at low heat.
Distillation in China may have begun during the Eastern Han dynasty (1st–2nd century CE)
Early evidence of distillation has been found related to alchemists working in Alexandria in Roman Egypt in the 1st century CE.
Distilled water has been in use since at least c. 200 CE, when Alexander of Aphrodisias described the process. Work on distilling other liquids continued in early Byzantine Egypt under Zosimus of Panopolis in the 3rd century.
Medieval Muslim chemists such as Jābir ibn Ḥayyān (Latin: Geber, ninth century) and Abū Bakr al-Rāzī (Latin: Rhazes, c. 865–925) experimented extensively with the distillation of various substances.
The distillation of wine is attested in Arabic works attributed to al-Kindī (c. 801–873 CE) and to al-Fārābī (c. 872–950), and in the 28th book of al-Zahrāwī's (Latin: Abulcasis, 936–1013) Kitāb al-Taṣrīf (later translated into Latin as Liber servatoris). In the twelfth century, recipes for the production of aqua ardens ("burning water", i.e., ethanol) by distilling wine with salt started to appear in a number of Latin works, and by the end of the thirteenth century it had become a widely known substance among Western European chemists. The works of Taddeo Alderotti (1223–1296) describe a method for concentrating alcohol involving repeated distillation through a water-cooled still, by which an alcohol purity of 90% could be obtained.
The fractional distillation of organic substances plays an important role in the works attributed to Jābir, such as in the Kitāb al-Sabʿīn ('The Book of Seventy'), translated into Latin by Gerard of Cremona (c. 1114–1187) under the title Liber de septuaginta. The Jabirian experiments with fractional distillation of animal and vegetable substances, and to a lesser degree also of mineral substances, is the main topic of the De anima in arte alkimiae, an originally Arabic work falsely attributed to Avicenna that was translated into Latin and would go on to form the most important alchemical source for Roger Bacon (c. 1220–1292).
The distillation of beverages began in the Southern Song (10th–13th century) and Jin (12th–13th century) dynasties, according to archaeological evidence. A still was found in an archaeological site in Qinglong, Hebei province, China, dating back to the 12th century. Distilled beverages were common during the Yuan dynasty (13th–14th century).
In 1500, German alchemist Hieronymus Brunschwig published Liber de arte distillandi de simplicibus (The Book of the Art of Distillation out of Simple Ingredients), the first book solely dedicated to the subject of distillation, followed in 1512 by a much expanded version. In 1651, John French published The Art of Distillation, the first major English compendium on the practice, but it has been claimed that much of it derives from Braunschweig's work. This includes diagrams with people in them showing the industrial rather than bench scale of the operation.
As alchemy evolved into the science of chemistry, vessels called retorts became used for distillations. Both alembics and retorts are forms of glassware with long necks pointing to the side at a downward angle to act as air-cooled condensers to condense the distillate and let it drip downward for collection. Later, copper alembics were invented. Riveted joints were often kept tight by using various mixtures, for instance a dough made of rye flour. These alembics often featured a cooling system around the beak, using cold water, for instance, which made the condensation of alcohol more efficient. These were called pot stills. Today, the retorts and pot stills have been largely supplanted by more efficient distillation methods in most industrial processes. However, the pot still is still widely used for the elaboration of some fine alcohols, such as cognac, Scotch whisky, Irish whiskey, tequila, rum, cachaça, and some vodkas. Pot stills made of various materials (wood, clay, stainless steel) are also used by bootleggers in various countries. Small pot stills are also sold for use in the domestic production of flower water or essential oils.
Early forms of distillation involved batch processes using one vaporization and one condensation. Purity was improved by further distillation of the condensate. Greater volumes were processed by simply repeating the distillation. Chemists reportedly carried out as many as 500 to 600 distillations in order to obtain a pure compound.
In the early 19th century, the basics of modern techniques, including pre-heating and reflux, were developed. In 1822, Anthony Perrier developed one of the first continuous stills, and then, in 1826, Robert Stein improved that design to make his patent still. In 1830, Aeneas Coffey got a patent for improving the design even further. Coffey's continuous still may be regarded as the archetype of modern petrochemical units. The French engineer Armand Savalle developed his steam regulator around 1846. In 1877, Ernest Solvay was granted a U.S. Patent for a tray column for ammonia distillation, and the same and subsequent years saw developments in this theme for oils and spirits.
With the emergence of chemical engineering as a discipline at the end of the 19th century, scientific rather than empirical methods could be applied. The developing petroleum industry in the early 20th century provided the impetus for the development of accurate design methods, such as the McCabe–Thiele method by Ernest Thiele and the Fenske equation. The first industrial plant in the United States to use distillation as a means of ocean desalination opened in Freeport, Texas in 1961 with the hope of bringing water security to the region. The availability of powerful computers has allowed direct computer simulations of distillation columns.
The application of distillation can roughly be divided into four groups: laboratory scale, industrial distillation, distillation of herbs for perfumery and medicinals (herbal distillate), and food processing. The latter two are distinctively different from the former two in that distillation is not used as a true purification method but more to transfer all volatiles from the source materials to the distillate in the processing of beverages and herbs.
The main difference between laboratory scale distillation and industrial distillation are that laboratory scale distillation is often performed on a batch basis, whereas industrial distillation often occurs continuously. In batch distillation, the composition of the source material, the vapors of the distilling compounds, and the distillate change during the distillation. In batch distillation, a still is charged (supplied) with a batch of feed mixture, which is then separated into its component fractions, which are collected sequentially from most volatile to less volatile, with the bottoms – remaining least or non-volatile fraction – removed at the end. The still can then be recharged and the process repeated.
In continuous distillation, the source materials, vapors, and distillate are kept at a constant composition by carefully replenishing the source material and removing fractions from both vapor and liquid in the system. This results in a more detailed control of the separation process.
The boiling point of a liquid is the temperature at which the vapor pressure of the liquid equals the pressure around the liquid, enabling bubbles to form without being crushed. A special case is the normal boiling point, where the vapor pressure of the liquid equals the ambient atmospheric pressure.
It is a misconception that in a liquid mixture at a given pressure, each component boils at the boiling point corresponding to the given pressure, allowing the vapors of each component to collect separately and purely. However, this does not occur, even in an idealized system. Idealized models of distillation are essentially governed by Raoult's law and Dalton's law and assume that vapor–liquid equilibria are attained.
Raoult's law states that the vapor pressure of a solution is dependent on 1) the vapor pressure of each chemical component in the solution and 2) the fraction of solution each component makes up, a.k.a. the mole fraction. This law applies to ideal solutions, or solutions that have different components but whose molecular interactions are the same as or very similar to pure solutions.
Dalton's law states that the total pressure is the sum of the partial pressures of each individual component in the mixture. When a multi-component liquid is heated, the vapor pressure of each component will rise, thus causing the total vapor pressure to rise. When the total vapor pressure reaches the pressure surrounding the liquid, boiling occurs and liquid turns to gas throughout the bulk of the liquid. A mixture with a given composition has one boiling point at a given pressure when the components are mutually soluble. A mixture of constant composition does not have multiple boiling points.
An implication of one boiling point is that lighter components never cleanly "boil first". At boiling point, all volatile components boil, but for a component, its percentage in the vapor is the same as its percentage of the total vapor pressure. Lighter components have a higher partial pressure and, thus, are concentrated in the vapor, but heavier volatile components also have a (smaller) partial pressure and necessarily vaporize also, albeit at a lower concentration in the vapor. Indeed, batch distillation and fractionation succeed by varying the composition of the mixture. In batch distillation, the batch vaporizes, which changes its composition; in fractionation, liquid higher in the fractionation column contains more lights and boils at lower temperatures. Therefore, starting from a given mixture, it appears to have a boiling range instead of a boiling point, although this is because its composition changes: each intermediate mixture has its own, singular boiling point.
The idealized model is accurate in the case of chemically similar liquids, such as benzene and toluene. In other cases, severe deviations from Raoult's law and Dalton's law are observed, most famously in the mixture of ethanol and water. These compounds, when heated together, form an azeotrope, which is when the vapor phase and liquid phase contain the same composition. Although there are computational methods that can be used to estimate the behavior of a mixture of arbitrary components, the only way to obtain accurate vapor–liquid equilibrium data is by measurement.
It is not possible to completely purify a mixture of components by distillation, as this would require each component in the mixture to have a zero partial pressure. If ultra-pure products are the goal, then further chemical separation must be applied. When a binary mixture is vaporized and the other component, e.g., a salt, has zero partial pressure for practical purposes, the process is simpler.
Heating an ideal mixture of two volatile substances, A and B, with A having the higher volatility, or lower boiling point, in a batch distillation setup (such as in an apparatus depicted in the opening figure) until the mixture is boiling results in a vapor above the liquid that contains a mixture of A and B. The ratio between A and B in the vapor will be different from the ratio in the liquid. The ratio in the liquid will be determined by how the original mixture was prepared, while the ratio in the vapor will be enriched in the more volatile compound, A (due to Raoult's Law, see above). The vapor goes through the condenser and is removed from the system. This, in turn, means that the ratio of compounds in the remaining liquid is now different from the initial ratio (i.e., more enriched in B than in the starting liquid).
The result is that the ratio in the liquid mixture is changing, becoming richer in component B. This causes the boiling point of the mixture to rise, which results in a rise in the temperature in the vapor, which results in a changing ratio of A : B in the gas phase (as distillation continues, there is an increasing proportion of B in the gas phase). This results in a slowly changing ratio of A : B in the distillate.
If the difference in vapour pressure between the two components A and B is large – generally expressed as the difference in boiling points – the mixture in the beginning of the distillation is highly enriched in component A, and when component A has distilled off, the boiling liquid is enriched in component B.
Continuous distillation is an ongoing distillation in which a liquid mixture is continuously (without interruption) fed into the process and separated fractions are removed continuously as output streams occur over time during the operation. Continuous distillation produces a minimum of two output fractions, including at least one volatile distillate fraction, which has boiled and been separately captured as a vapor and then condensed to a liquid. There is always a bottoms (or residue) fraction, which is the least volatile residue that has not been separately captured as a condensed vapor.
Continuous distillation differs from batch distillation in the respect that concentrations should not change over time. Continuous distillation can be run at a steady state for an arbitrary amount of time. For any source material of specific composition, the main variables that affect the purity of products in continuous distillation are the reflux ratio and the number of theoretical equilibrium stages, in practice determined by the number of trays or the height of packing. Reflux is a flow from the condenser back to the column, which generates a recycle that allows a better separation with a given number of trays. Equilibrium stages are ideal steps where compositions achieve vapor–liquid equilibrium, repeating the separation process and allowing better separation given a reflux ratio. A column with a high reflux ratio may have fewer stages, but it refluxes a large amount of liquid, giving a wide column with a large holdup. Conversely, a column with a low reflux ratio must have a large number of stages, thus requiring a taller column.
Both batch and continuous distillations can be improved by making use of a fractionating column on top of the distillation flask. The column improves separation by providing a larger surface area for the vapor and condensate to come into contact. This helps it remain at equilibrium for as long as possible. The column can even consist of small subsystems ('trays' or 'dishes') which all contain an enriched, boiling liquid mixture, all with their own vapor–liquid equilibrium.
There are differences between laboratory-scale and industrial-scale fractionating columns, but the principles are the same. Examples of laboratory-scale fractionating columns (in increasing efficiency) include:
Laboratory scale distillations are almost exclusively run as batch distillations. The device used in distillation, sometimes referred to as a still, consists at a minimum of a reboiler or pot in which the source material is heated, a condenser in which the heated vapor is cooled back to the liquid state, and a receiver in which the concentrated or purified liquid, called the distillate, is collected. Several laboratory scale techniques for distillation exist (see also distillation types).
A completely sealed distillation apparatus could experience extreme and rapidly varying internal pressure, which could cause it to burst open at the joints. Therefore, some path is usually left open (for instance, at the receiving flask) to allow the internal pressure to equalize with atmospheric pressure. Alternatively, a vacuum pump may be used to keep the apparatus at a lower than atmospheric pressure. If the substances involved are air- or moisture-sensitive, the connection to the atmosphere can be made through one or more drying tubes packed with materials that scavenge the undesired air components, or through bubblers that provide a movable liquid barrier. Finally, the entry of undesired air components can be prevented by pumping a low but steady flow of suitable inert gas, like nitrogen, into the apparatus.
In simple distillation, the vapor is immediately channeled into a condenser. Consequently, the distillate is not pure but rather its composition is identical to the composition of the vapors at the given temperature and pressure. That concentration follows Raoult's law.
As a result, simple distillation is effective only when the liquid boiling points differ greatly (rule of thumb is 25 °C) or when separating liquids from non-volatile solids or oils. For these cases, the vapor pressures of the components are usually different enough that the distillate may be sufficiently pure for its intended purpose.
A cutaway schematic of a simple distillation operation is shown at right. The starting liquid 15 in the boiling flask 2 is heated by a combined hotplate and magnetic stirrer 13 via a silicone oil bath (orange, 14). The vapor flows through a short Vigreux column 3, then through a Liebig condenser 5, is cooled by water (blue) that circulates through ports 6 and 7. The condensed liquid drips into the receiving flask 8, sitting in a cooling bath (blue, 16). The adapter 10 has a connection 9 that may be fitted to a vacuum pump. The components are connected by ground glass joints.
For many cases, the boiling points of the components in the mixture will be sufficiently close that Raoult's law must be taken into consideration. Therefore, fractional distillation must be used in order to separate the components by repeated vaporization-condensation cycles within a packed fractionating column. This separation, by successive distillations, is also referred to as rectification.
As the solution to be purified is heated, its vapors rise to the fractionating column. As it rises, it cools, condensing on the condenser walls and the surfaces of the packing material. Here, the condensate continues to be heated by the rising hot vapors; it vaporizes once more. However, the composition of the fresh vapors is determined once again by Raoult's law. Each vaporization-condensation cycle (called a theoretical plate) will yield a purer solution of the more volatile component. In reality, each cycle at a given temperature does not occur at exactly the same position in the fractionating column; theoretical plate is thus a concept rather than an accurate description.
More theoretical plates lead to better separations. A spinning band distillation system uses a spinning band of Teflon or metal to force the rising vapors into close contact with the descending condensate, increasing the number of theoretical plates.
Like vacuum distillation, steam distillation is a method for distilling compounds which are heat-sensitive. The temperature of the steam is easier to control than the surface of a heating element and allows a high rate of heat transfer without heating at a very high temperature. This process involves bubbling steam through a heated mixture of the raw material. By Raoult's law, some of the target compound will vaporize (in accordance with its partial pressure). The vapor mixture is cooled and condensed, usually yielding a layer of oil and a layer of water.
Steam distillation of various aromatic herbs and flowers can result in two products: an essential oil as well as a watery herbal distillate. The essential oils are often used in perfumery and aromatherapy while the watery distillates have many applications in aromatherapy, food processing and skin care.
Some compounds have very high boiling points. To boil such compounds, it is often better to lower the pressure at which such compounds are boiled instead of increasing the temperature. Once the pressure is lowered to the vapor pressure of the compound (at the given temperature), boiling and the rest of the distillation process can commence. This technique is referred to as vacuum distillation and it is commonly found in the laboratory in the form of the rotary evaporator.
This technique is also very useful for compounds which boil beyond their decomposition temperature at atmospheric pressure and which would therefore be decomposed by any attempt to boil them under atmospheric pressure.
Molecular distillation is vacuum distillation below the pressure of 0.01 torr. 0.01 torr is one order of magnitude above high vacuum, where fluids are in the free molecular flow regime, i.e., the mean free path of molecules is comparable to the size of the equipment. The gaseous phase no longer exerts significant pressure on the substance to be evaporated, and consequently, rate of evaporation no longer depends on pressure. That is, because the continuum assumptions of fluid dynamics no longer apply, mass transport is governed by molecular dynamics rather than fluid dynamics. Thus, a short path between the hot surface and the cold surface is necessary, typically by suspending a hot plate covered with a film of feed next to a cold plate with a line of sight in between. Molecular distillation is used industrially for purification of oils.
Short path distillation is a distillation technique that involves the distillate travelling a short distance, often only a few centimeters, and is normally done at reduced pressure. A classic example would be a distillation involving the distillate travelling from one glass bulb to another, without the need for a condenser separating the two chambers. This technique is often used for compounds which are unstable at high temperatures or to purify small amounts of compound. The advantage is that the heating temperature can be considerably lower (at reduced pressure) than the boiling point of the liquid at standard pressure, and the distillate only has to travel a short distance before condensing. A short path ensures that little compound is lost on the sides of the apparatus. The Kugelrohr apparatus is a kind of short path distillation method which often contains multiple chambers to collect distillate fractions.
Some compounds have high boiling points as well as being air sensitive. A simple vacuum distillation system as exemplified above can be used, whereby the vacuum is replaced with an inert gas after the distillation is complete. However, this is a less satisfactory system if one desires to collect fractions under a reduced pressure. To do this a "cow" or "pig" adaptor can be added to the end of the condenser, or for better results or for very air sensitive compounds a Perkin triangle apparatus can be used.
The Perkin triangle has means via a series of glass or Teflon taps to allows fractions to be isolated from the rest of the still, without the main body of the distillation being removed from either the vacuum or heat source, and thus can remain in a state of reflux. To do this, the sample is first isolated from the vacuum by means of the taps, the vacuum over the sample is then replaced with an inert gas (such as nitrogen or argon) and can then be stoppered and removed. A fresh collection vessel can then be added to the system, evacuated and linked back into the distillation system via the taps to collect a second fraction, and so on, until all fractions have been collected.
Zone distillation is a distillation process in a long container with partial melting of refined matter in moving liquid zone and condensation of vapor in the solid phase at condensate pulling in cold area. The process is worked in theory. When zone heater is moving from the top to the bottom of the container then solid condensate with irregular impurity distribution is forming. Then most pure part of the condensate may be extracted as product. The process may be iterated many times by moving (without turnover) the received condensate to the bottom part of the container on the place of refined matter. The irregular impurity distribution in the condensate (that is efficiency of purification) increases with the number of iterations. Zone distillation is the distillation analog of zone recrystallization. Impurity distribution in the condensate is described by known equations of zone recrystallization – with the replacement of the distribution co-efficient k of crystallization - for the separation factor α of distillation.
Non-condensable gas can be expelled from the apparatus by the vapor of relatively volatile co-solvent, which spontaneously evaporates during initial pumping, and this can be achieved with regular oil or diaphragm pump.
The unit process of evaporation may also be called "distillation":
Other uses:
Interactions between the components of the solution create properties unique to the solution, as most processes entail non-ideal mixtures, where Raoult's law does not hold. Such interactions can result in a constant-boiling azeotrope which behaves as if it were a pure compound (i.e., boils at a single temperature instead of a range). At an azeotrope, the solution contains the given component in the same proportion as the vapor, so that evaporation does not change the purity, and distillation does not effect separation. For example, ethyl alcohol and water form an azeotrope of 95.6% at 78.1 °C.
If the azeotrope is not considered sufficiently pure for use, there exist some techniques to break the azeotrope to give a pure distillate. This set of techniques are known as azeotropic distillation. Some techniques achieve this by "jumping" over the azeotropic composition (by adding another component to create a new azeotrope, or by varying the pressure). Others work by chemically or physically removing or sequestering the impurity. For example, to purify ethanol beyond 95%, a drying agent (or desiccant, such as potassium carbonate) can be added to convert the soluble water into insoluble water of crystallization. Molecular sieves are often used for this purpose as well.
Immiscible liquids, such as water and toluene, easily form azeotropes. Commonly, these azeotropes are referred to as a low boiling azeotrope because the boiling point of the azeotrope is lower than the boiling point of either pure component. The temperature and composition of the azeotrope is easily predicted from the vapor pressure of the pure components, without use of Raoult's law. The azeotrope is easily broken in a distillation set-up by using a liquid–liquid separator (a decanter) to separate the two liquid layers that are condensed overhead. Only one of the two liquid layers is refluxed to the distillation set-up.
High boiling azeotropes, such as a 20 percent by weight mixture of hydrochloric acid in water, also exist. As implied by the name, the boiling point of the azeotrope is greater than the boiling point of either pure component.
To break azeotropic distillations and cross distillation boundaries, such as in the DeRosier problem, it is necessary to increase the composition of the light key in the distillate.
The boiling points of components in an azeotrope overlap to form a band. By exposing an azeotrope to a vacuum or positive pressure, it's possible to bias the boiling point of one component away from the other by exploiting the differing vapor pressure curves of each; the curves may overlap at the azeotropic point, but are unlikely to remain identical further along the pressure axis to either side of the azeotropic point. When the bias is great enough, the two boiling points no longer overlap and so the azeotropic band disappears.
This method can remove the need to add other chemicals to a distillation, but it has two potential drawbacks.
Under negative pressure, power for a vacuum source is needed and the reduced boiling points of the distillates requires that the condenser be run cooler to prevent distillate vapors being lost to the vacuum source. Increased cooling demands will often require additional energy and possibly new equipment or a change of coolant.
Alternatively, if positive pressures are required, standard glassware can not be used, energy must be used for pressurization and there is a higher chance of side reactions occurring in the distillation, such as decomposition, due to the higher temperatures required to effect boiling.
A unidirectional distillation will rely on a pressure change in one direction, either positive or negative.
Pressure-swing distillation is essentially the same as the unidirectional distillation used to break azeotropic mixtures, but here both positive and negative pressures may be employed.
This improves the selectivity of the distillation and allows a chemist to optimize distillation by avoiding extremes of pressure and temperature that waste energy. This is particularly important in commercial applications.
One example of the application of pressure-swing distillation is during the industrial purification of ethyl acetate after its catalytic synthesis from ethanol.
Large scale industrial distillation applications include both batch and continuous fractional, vacuum, azeotropic, extractive, and steam distillation. The most widely used industrial applications of continuous, steady-state fractional distillation are in petroleum refineries, petrochemical and chemical plants and natural gas processing plants.
To control and optimize such industrial distillation, a standardized laboratory method, ASTM D86, is established. This test method extends to the atmospheric distillation of petroleum products using a laboratory batch distillation unit to quantitatively determine the boiling range characteristics of petroleum products.
Industrial distillation is typically performed in large, vertical cylindrical columns known as distillation towers or distillation columns with diameters ranging from about 0.65 to 16 metres (2 ft 2 in to 52 ft 6 in) and heights ranging from about 6 to 90 metres (20 to 295 ft) or more. When the process feed has a diverse composition, as in distilling crude oil, liquid outlets at intervals up the column allow for the withdrawal of different fractions or products having different boiling points or boiling ranges. The "lightest" products (those with the lowest boiling point) exit from the top of the columns and the "heaviest" products (those with the highest boiling point) exit from the bottom of the column and are often called the bottoms.
Industrial towers use reflux to achieve a more complete separation of products. Reflux refers to the portion of the condensed overhead liquid product from a distillation or fractionation tower that is returned to the upper part of the tower as shown in the schematic diagram of a typical, large-scale industrial distillation tower. Inside the tower, the downflowing reflux liquid provides cooling and condensation of the upflowing vapors thereby increasing the efficiency of the distillation tower. The more reflux that is provided for a given number of theoretical plates, the better the tower's separation of lower boiling materials from higher boiling materials. Alternatively, the more reflux that is provided for a given desired separation, the fewer the number of theoretical plates required. Chemical engineers must choose what combination of reflux rate and number of plates is both economically and physically feasible for the products purified in the distillation column.
Such industrial fractionating towers are also used in cryogenic air separation, producing liquid oxygen, liquid nitrogen, and high purity argon. Distillation of chlorosilanes also enables the production of high-purity silicon for use as a semiconductor.
Design and operation of a distillation tower depends on the feed and desired products. Given a simple, binary component feed, analytical methods such as the McCabe–Thiele method or the Fenske equation can be used. For a multi-component feed, simulation models are used both for design and operation. Moreover, the efficiencies of the vapor–liquid contact devices (referred to as "plates" or "trays") used in distillation towers are typically lower than that of a theoretical 100% efficient equilibrium stage. Hence, a distillation tower needs more trays than the number of theoretical vapor–liquid equilibrium stages. A variety of models have been postulated to estimate tray efficiencies.
In modern industrial uses, a packing material is used in the column instead of trays when low pressure drops across the column are required. Other factors that favor packing are: vacuum systems, smaller diameter columns, corrosive systems, systems prone to foaming, systems requiring low liquid holdup, and batch distillation. Conversely, factors that favor plate columns are: presence of solids in feed, high liquid rates, large column diameters, complex columns, columns with wide feed composition variation, columns with a chemical reaction, absorption columns, columns limited by foundation weight tolerance, low liquid rate, large turn-down ratio and those processes subject to process surges.
This packing material can either be random dumped packing (25–76 millimetres (1–3 in) wide) such as Raschig rings or structured sheet metal. Liquids tend to wet the surface of the packing and the vapors pass across this wetted surface, where mass transfer takes place. Unlike conventional tray distillation in which every tray represents a separate point of vapor–liquid equilibrium, the vapor–liquid equilibrium curve in a packed column is continuous. However, when modeling packed columns, it is useful to compute a number of "theoretical stages" to denote the separation efficiency of the packed column with respect to more traditional trays. Differently shaped packings have different surface areas and void space between packings. Both of these factors affect packing performance.
Another factor in addition to the packing shape and surface area that affects the performance of random or structured packing is the liquid and vapor distribution entering the packed bed. The number of theoretical stages required to make a given separation is calculated using a specific vapor to liquid ratio. If the liquid and vapor are not evenly distributed across the superficial tower area as it enters the packed bed, the liquid to vapor ratio will not be correct in the packed bed and the required separation will not be achieved. The packing will appear to not be working properly. The height equivalent to a theoretical plate (HETP) will be greater than expected. The problem is not the packing itself but the mal-distribution of the fluids entering the packed bed. Liquid mal-distribution is more frequently the problem than vapor. The design of the liquid distributors used to introduce the feed and reflux to a packed bed is critical to making the packing perform to it maximum efficiency. Methods of evaluating the effectiveness of a liquid distributor to evenly distribute the liquid entering a packed bed can be found in references. Considerable work has been done on this topic by Fractionation Research, Inc. (commonly known as FRI).
The goal of multi-effect distillation is to increase the energy efficiency of the process, for use in desalination, or in some cases one stage in the production of ultrapure water. The number of effects is inversely proportional to the kW·h/m of water recovered figure and refers to the volume of water recovered per unit of energy compared with single-effect distillation. One effect is roughly 636 kW·h/m:
There are many other types of multi-effect distillation processes, including one referred to as simply multi-effect distillation (MED), in which multiple chambers, with intervening heat exchangers, are employed.
Carbohydrate-containing plant materials are allowed to ferment, producing a dilute solution of ethanol in the process. Spirits such as whiskey and rum are prepared by distilling these dilute solutions of ethanol. Components other than ethanol, including water, esters, and other alcohols, are collected in the condensate, which account for the flavor of the beverage. Some of these beverages are then stored in barrels or other containers to acquire more flavor compounds and characteristic flavors. | [
{
"paragraph_id": 0,
"text": "Distillation, or classical distillation, is the process of separating the components or substances from a liquid mixture by using selective boiling and condensation, usually inside an apparatus known as a still. Dry distillation is the heating of solid materials to produce gaseous products (which may condense into liquids or solids); this may involve chemical changes such as destructive distillation or cracking. Distillation may result in essentially complete separation (resulting in nearly pure components), or it may be a partial separation that increases the concentration of selected components; in either case, the process exploits differences in the relative volatility of the mixture's components. In industrial applications, distillation is a unit operation of practically universal importance, but is a physical separation process, not a chemical reaction. An installation used for distillation, especially of distilled beverages, is a distillery. Distillation includes the following applications:",
"title": ""
},
{
"paragraph_id": 1,
"text": "Early evidence of distillation was found on Akkadian tablets dated c. 1200 BCE describing perfumery operations. The tablets provided textual evidence that an early, primitive form of distillation was known to the Babylonians of ancient Mesopotamia.",
"title": "History"
},
{
"paragraph_id": 2,
"text": "Aristotle knew that water condensing from evaporating seawater is fresh:",
"title": "History"
},
{
"paragraph_id": 3,
"text": "I have proved by experiment that salt water evaporated forms fresh, and the vapour does not, when it condenses, condense into sea water again.",
"title": "History"
},
{
"paragraph_id": 4,
"text": "Letting seawater evaporate and condense into freshwater is not distillation, for distillation involves boiling, but the experiment may have been an important step towards distillation.",
"title": "History"
},
{
"paragraph_id": 5,
"text": "Distillation was practiced in the ancient Indian subcontinent, which is evident from baked clay retorts and receivers found at Taxila, Shaikhan Dheri, and Charsadda in Pakistan and Rang Mahal in India dating to the early centuries of the Common Era. Frank Raymond Allchin says these terracotta distill tubes were \"made to imitate bamboo\". These \"Gandhara stills\" were only capable of producing very weak liquor, as there was no efficient means of collecting the vapors at low heat.",
"title": "History"
},
{
"paragraph_id": 6,
"text": "Distillation in China may have begun during the Eastern Han dynasty (1st–2nd century CE)",
"title": "History"
},
{
"paragraph_id": 7,
"text": "Early evidence of distillation has been found related to alchemists working in Alexandria in Roman Egypt in the 1st century CE.",
"title": "History"
},
{
"paragraph_id": 8,
"text": "Distilled water has been in use since at least c. 200 CE, when Alexander of Aphrodisias described the process. Work on distilling other liquids continued in early Byzantine Egypt under Zosimus of Panopolis in the 3rd century.",
"title": "History"
},
{
"paragraph_id": 9,
"text": "Medieval Muslim chemists such as Jābir ibn Ḥayyān (Latin: Geber, ninth century) and Abū Bakr al-Rāzī (Latin: Rhazes, c. 865–925) experimented extensively with the distillation of various substances.",
"title": "History"
},
{
"paragraph_id": 10,
"text": "The distillation of wine is attested in Arabic works attributed to al-Kindī (c. 801–873 CE) and to al-Fārābī (c. 872–950), and in the 28th book of al-Zahrāwī's (Latin: Abulcasis, 936–1013) Kitāb al-Taṣrīf (later translated into Latin as Liber servatoris). In the twelfth century, recipes for the production of aqua ardens (\"burning water\", i.e., ethanol) by distilling wine with salt started to appear in a number of Latin works, and by the end of the thirteenth century it had become a widely known substance among Western European chemists. The works of Taddeo Alderotti (1223–1296) describe a method for concentrating alcohol involving repeated distillation through a water-cooled still, by which an alcohol purity of 90% could be obtained.",
"title": "History"
},
{
"paragraph_id": 11,
"text": "The fractional distillation of organic substances plays an important role in the works attributed to Jābir, such as in the Kitāb al-Sabʿīn ('The Book of Seventy'), translated into Latin by Gerard of Cremona (c. 1114–1187) under the title Liber de septuaginta. The Jabirian experiments with fractional distillation of animal and vegetable substances, and to a lesser degree also of mineral substances, is the main topic of the De anima in arte alkimiae, an originally Arabic work falsely attributed to Avicenna that was translated into Latin and would go on to form the most important alchemical source for Roger Bacon (c. 1220–1292).",
"title": "History"
},
{
"paragraph_id": 12,
"text": "The distillation of beverages began in the Southern Song (10th–13th century) and Jin (12th–13th century) dynasties, according to archaeological evidence. A still was found in an archaeological site in Qinglong, Hebei province, China, dating back to the 12th century. Distilled beverages were common during the Yuan dynasty (13th–14th century).",
"title": "History"
},
{
"paragraph_id": 13,
"text": "In 1500, German alchemist Hieronymus Brunschwig published Liber de arte distillandi de simplicibus (The Book of the Art of Distillation out of Simple Ingredients), the first book solely dedicated to the subject of distillation, followed in 1512 by a much expanded version. In 1651, John French published The Art of Distillation, the first major English compendium on the practice, but it has been claimed that much of it derives from Braunschweig's work. This includes diagrams with people in them showing the industrial rather than bench scale of the operation.",
"title": "History"
},
{
"paragraph_id": 14,
"text": "As alchemy evolved into the science of chemistry, vessels called retorts became used for distillations. Both alembics and retorts are forms of glassware with long necks pointing to the side at a downward angle to act as air-cooled condensers to condense the distillate and let it drip downward for collection. Later, copper alembics were invented. Riveted joints were often kept tight by using various mixtures, for instance a dough made of rye flour. These alembics often featured a cooling system around the beak, using cold water, for instance, which made the condensation of alcohol more efficient. These were called pot stills. Today, the retorts and pot stills have been largely supplanted by more efficient distillation methods in most industrial processes. However, the pot still is still widely used for the elaboration of some fine alcohols, such as cognac, Scotch whisky, Irish whiskey, tequila, rum, cachaça, and some vodkas. Pot stills made of various materials (wood, clay, stainless steel) are also used by bootleggers in various countries. Small pot stills are also sold for use in the domestic production of flower water or essential oils.",
"title": "History"
},
{
"paragraph_id": 15,
"text": "Early forms of distillation involved batch processes using one vaporization and one condensation. Purity was improved by further distillation of the condensate. Greater volumes were processed by simply repeating the distillation. Chemists reportedly carried out as many as 500 to 600 distillations in order to obtain a pure compound.",
"title": "History"
},
{
"paragraph_id": 16,
"text": "In the early 19th century, the basics of modern techniques, including pre-heating and reflux, were developed. In 1822, Anthony Perrier developed one of the first continuous stills, and then, in 1826, Robert Stein improved that design to make his patent still. In 1830, Aeneas Coffey got a patent for improving the design even further. Coffey's continuous still may be regarded as the archetype of modern petrochemical units. The French engineer Armand Savalle developed his steam regulator around 1846. In 1877, Ernest Solvay was granted a U.S. Patent for a tray column for ammonia distillation, and the same and subsequent years saw developments in this theme for oils and spirits.",
"title": "History"
},
{
"paragraph_id": 17,
"text": "With the emergence of chemical engineering as a discipline at the end of the 19th century, scientific rather than empirical methods could be applied. The developing petroleum industry in the early 20th century provided the impetus for the development of accurate design methods, such as the McCabe–Thiele method by Ernest Thiele and the Fenske equation. The first industrial plant in the United States to use distillation as a means of ocean desalination opened in Freeport, Texas in 1961 with the hope of bringing water security to the region. The availability of powerful computers has allowed direct computer simulations of distillation columns.",
"title": "History"
},
{
"paragraph_id": 18,
"text": "The application of distillation can roughly be divided into four groups: laboratory scale, industrial distillation, distillation of herbs for perfumery and medicinals (herbal distillate), and food processing. The latter two are distinctively different from the former two in that distillation is not used as a true purification method but more to transfer all volatiles from the source materials to the distillate in the processing of beverages and herbs.",
"title": "Applications"
},
{
"paragraph_id": 19,
"text": "The main difference between laboratory scale distillation and industrial distillation are that laboratory scale distillation is often performed on a batch basis, whereas industrial distillation often occurs continuously. In batch distillation, the composition of the source material, the vapors of the distilling compounds, and the distillate change during the distillation. In batch distillation, a still is charged (supplied) with a batch of feed mixture, which is then separated into its component fractions, which are collected sequentially from most volatile to less volatile, with the bottoms – remaining least or non-volatile fraction – removed at the end. The still can then be recharged and the process repeated.",
"title": "Applications"
},
{
"paragraph_id": 20,
"text": "In continuous distillation, the source materials, vapors, and distillate are kept at a constant composition by carefully replenishing the source material and removing fractions from both vapor and liquid in the system. This results in a more detailed control of the separation process.",
"title": "Applications"
},
{
"paragraph_id": 21,
"text": "The boiling point of a liquid is the temperature at which the vapor pressure of the liquid equals the pressure around the liquid, enabling bubbles to form without being crushed. A special case is the normal boiling point, where the vapor pressure of the liquid equals the ambient atmospheric pressure.",
"title": "Idealized model"
},
{
"paragraph_id": 22,
"text": "It is a misconception that in a liquid mixture at a given pressure, each component boils at the boiling point corresponding to the given pressure, allowing the vapors of each component to collect separately and purely. However, this does not occur, even in an idealized system. Idealized models of distillation are essentially governed by Raoult's law and Dalton's law and assume that vapor–liquid equilibria are attained.",
"title": "Idealized model"
},
{
"paragraph_id": 23,
"text": "Raoult's law states that the vapor pressure of a solution is dependent on 1) the vapor pressure of each chemical component in the solution and 2) the fraction of solution each component makes up, a.k.a. the mole fraction. This law applies to ideal solutions, or solutions that have different components but whose molecular interactions are the same as or very similar to pure solutions.",
"title": "Idealized model"
},
{
"paragraph_id": 24,
"text": "Dalton's law states that the total pressure is the sum of the partial pressures of each individual component in the mixture. When a multi-component liquid is heated, the vapor pressure of each component will rise, thus causing the total vapor pressure to rise. When the total vapor pressure reaches the pressure surrounding the liquid, boiling occurs and liquid turns to gas throughout the bulk of the liquid. A mixture with a given composition has one boiling point at a given pressure when the components are mutually soluble. A mixture of constant composition does not have multiple boiling points.",
"title": "Idealized model"
},
{
"paragraph_id": 25,
"text": "An implication of one boiling point is that lighter components never cleanly \"boil first\". At boiling point, all volatile components boil, but for a component, its percentage in the vapor is the same as its percentage of the total vapor pressure. Lighter components have a higher partial pressure and, thus, are concentrated in the vapor, but heavier volatile components also have a (smaller) partial pressure and necessarily vaporize also, albeit at a lower concentration in the vapor. Indeed, batch distillation and fractionation succeed by varying the composition of the mixture. In batch distillation, the batch vaporizes, which changes its composition; in fractionation, liquid higher in the fractionation column contains more lights and boils at lower temperatures. Therefore, starting from a given mixture, it appears to have a boiling range instead of a boiling point, although this is because its composition changes: each intermediate mixture has its own, singular boiling point.",
"title": "Idealized model"
},
{
"paragraph_id": 26,
"text": "The idealized model is accurate in the case of chemically similar liquids, such as benzene and toluene. In other cases, severe deviations from Raoult's law and Dalton's law are observed, most famously in the mixture of ethanol and water. These compounds, when heated together, form an azeotrope, which is when the vapor phase and liquid phase contain the same composition. Although there are computational methods that can be used to estimate the behavior of a mixture of arbitrary components, the only way to obtain accurate vapor–liquid equilibrium data is by measurement.",
"title": "Idealized model"
},
{
"paragraph_id": 27,
"text": "It is not possible to completely purify a mixture of components by distillation, as this would require each component in the mixture to have a zero partial pressure. If ultra-pure products are the goal, then further chemical separation must be applied. When a binary mixture is vaporized and the other component, e.g., a salt, has zero partial pressure for practical purposes, the process is simpler.",
"title": "Idealized model"
},
{
"paragraph_id": 28,
"text": "Heating an ideal mixture of two volatile substances, A and B, with A having the higher volatility, or lower boiling point, in a batch distillation setup (such as in an apparatus depicted in the opening figure) until the mixture is boiling results in a vapor above the liquid that contains a mixture of A and B. The ratio between A and B in the vapor will be different from the ratio in the liquid. The ratio in the liquid will be determined by how the original mixture was prepared, while the ratio in the vapor will be enriched in the more volatile compound, A (due to Raoult's Law, see above). The vapor goes through the condenser and is removed from the system. This, in turn, means that the ratio of compounds in the remaining liquid is now different from the initial ratio (i.e., more enriched in B than in the starting liquid).",
"title": "Idealized model"
},
{
"paragraph_id": 29,
"text": "The result is that the ratio in the liquid mixture is changing, becoming richer in component B. This causes the boiling point of the mixture to rise, which results in a rise in the temperature in the vapor, which results in a changing ratio of A : B in the gas phase (as distillation continues, there is an increasing proportion of B in the gas phase). This results in a slowly changing ratio of A : B in the distillate.",
"title": "Idealized model"
},
{
"paragraph_id": 30,
"text": "If the difference in vapour pressure between the two components A and B is large – generally expressed as the difference in boiling points – the mixture in the beginning of the distillation is highly enriched in component A, and when component A has distilled off, the boiling liquid is enriched in component B.",
"title": "Idealized model"
},
{
"paragraph_id": 31,
"text": "Continuous distillation is an ongoing distillation in which a liquid mixture is continuously (without interruption) fed into the process and separated fractions are removed continuously as output streams occur over time during the operation. Continuous distillation produces a minimum of two output fractions, including at least one volatile distillate fraction, which has boiled and been separately captured as a vapor and then condensed to a liquid. There is always a bottoms (or residue) fraction, which is the least volatile residue that has not been separately captured as a condensed vapor.",
"title": "Idealized model"
},
{
"paragraph_id": 32,
"text": "Continuous distillation differs from batch distillation in the respect that concentrations should not change over time. Continuous distillation can be run at a steady state for an arbitrary amount of time. For any source material of specific composition, the main variables that affect the purity of products in continuous distillation are the reflux ratio and the number of theoretical equilibrium stages, in practice determined by the number of trays or the height of packing. Reflux is a flow from the condenser back to the column, which generates a recycle that allows a better separation with a given number of trays. Equilibrium stages are ideal steps where compositions achieve vapor–liquid equilibrium, repeating the separation process and allowing better separation given a reflux ratio. A column with a high reflux ratio may have fewer stages, but it refluxes a large amount of liquid, giving a wide column with a large holdup. Conversely, a column with a low reflux ratio must have a large number of stages, thus requiring a taller column.",
"title": "Idealized model"
},
{
"paragraph_id": 33,
"text": "Both batch and continuous distillations can be improved by making use of a fractionating column on top of the distillation flask. The column improves separation by providing a larger surface area for the vapor and condensate to come into contact. This helps it remain at equilibrium for as long as possible. The column can even consist of small subsystems ('trays' or 'dishes') which all contain an enriched, boiling liquid mixture, all with their own vapor–liquid equilibrium.",
"title": "Idealized model"
},
{
"paragraph_id": 34,
"text": "There are differences between laboratory-scale and industrial-scale fractionating columns, but the principles are the same. Examples of laboratory-scale fractionating columns (in increasing efficiency) include:",
"title": "Idealized model"
},
{
"paragraph_id": 35,
"text": "Laboratory scale distillations are almost exclusively run as batch distillations. The device used in distillation, sometimes referred to as a still, consists at a minimum of a reboiler or pot in which the source material is heated, a condenser in which the heated vapor is cooled back to the liquid state, and a receiver in which the concentrated or purified liquid, called the distillate, is collected. Several laboratory scale techniques for distillation exist (see also distillation types).",
"title": "Laboratory procedures"
},
{
"paragraph_id": 36,
"text": "A completely sealed distillation apparatus could experience extreme and rapidly varying internal pressure, which could cause it to burst open at the joints. Therefore, some path is usually left open (for instance, at the receiving flask) to allow the internal pressure to equalize with atmospheric pressure. Alternatively, a vacuum pump may be used to keep the apparatus at a lower than atmospheric pressure. If the substances involved are air- or moisture-sensitive, the connection to the atmosphere can be made through one or more drying tubes packed with materials that scavenge the undesired air components, or through bubblers that provide a movable liquid barrier. Finally, the entry of undesired air components can be prevented by pumping a low but steady flow of suitable inert gas, like nitrogen, into the apparatus.",
"title": "Laboratory procedures"
},
{
"paragraph_id": 37,
"text": "In simple distillation, the vapor is immediately channeled into a condenser. Consequently, the distillate is not pure but rather its composition is identical to the composition of the vapors at the given temperature and pressure. That concentration follows Raoult's law.",
"title": "Laboratory procedures"
},
{
"paragraph_id": 38,
"text": "As a result, simple distillation is effective only when the liquid boiling points differ greatly (rule of thumb is 25 °C) or when separating liquids from non-volatile solids or oils. For these cases, the vapor pressures of the components are usually different enough that the distillate may be sufficiently pure for its intended purpose.",
"title": "Laboratory procedures"
},
{
"paragraph_id": 39,
"text": "A cutaway schematic of a simple distillation operation is shown at right. The starting liquid 15 in the boiling flask 2 is heated by a combined hotplate and magnetic stirrer 13 via a silicone oil bath (orange, 14). The vapor flows through a short Vigreux column 3, then through a Liebig condenser 5, is cooled by water (blue) that circulates through ports 6 and 7. The condensed liquid drips into the receiving flask 8, sitting in a cooling bath (blue, 16). The adapter 10 has a connection 9 that may be fitted to a vacuum pump. The components are connected by ground glass joints.",
"title": "Laboratory procedures"
},
{
"paragraph_id": 40,
"text": "For many cases, the boiling points of the components in the mixture will be sufficiently close that Raoult's law must be taken into consideration. Therefore, fractional distillation must be used in order to separate the components by repeated vaporization-condensation cycles within a packed fractionating column. This separation, by successive distillations, is also referred to as rectification.",
"title": "Laboratory procedures"
},
{
"paragraph_id": 41,
"text": "As the solution to be purified is heated, its vapors rise to the fractionating column. As it rises, it cools, condensing on the condenser walls and the surfaces of the packing material. Here, the condensate continues to be heated by the rising hot vapors; it vaporizes once more. However, the composition of the fresh vapors is determined once again by Raoult's law. Each vaporization-condensation cycle (called a theoretical plate) will yield a purer solution of the more volatile component. In reality, each cycle at a given temperature does not occur at exactly the same position in the fractionating column; theoretical plate is thus a concept rather than an accurate description.",
"title": "Laboratory procedures"
},
{
"paragraph_id": 42,
"text": "More theoretical plates lead to better separations. A spinning band distillation system uses a spinning band of Teflon or metal to force the rising vapors into close contact with the descending condensate, increasing the number of theoretical plates.",
"title": "Laboratory procedures"
},
{
"paragraph_id": 43,
"text": "Like vacuum distillation, steam distillation is a method for distilling compounds which are heat-sensitive. The temperature of the steam is easier to control than the surface of a heating element and allows a high rate of heat transfer without heating at a very high temperature. This process involves bubbling steam through a heated mixture of the raw material. By Raoult's law, some of the target compound will vaporize (in accordance with its partial pressure). The vapor mixture is cooled and condensed, usually yielding a layer of oil and a layer of water.",
"title": "Laboratory procedures"
},
{
"paragraph_id": 44,
"text": "Steam distillation of various aromatic herbs and flowers can result in two products: an essential oil as well as a watery herbal distillate. The essential oils are often used in perfumery and aromatherapy while the watery distillates have many applications in aromatherapy, food processing and skin care.",
"title": "Laboratory procedures"
},
{
"paragraph_id": 45,
"text": "Some compounds have very high boiling points. To boil such compounds, it is often better to lower the pressure at which such compounds are boiled instead of increasing the temperature. Once the pressure is lowered to the vapor pressure of the compound (at the given temperature), boiling and the rest of the distillation process can commence. This technique is referred to as vacuum distillation and it is commonly found in the laboratory in the form of the rotary evaporator.",
"title": "Laboratory procedures"
},
{
"paragraph_id": 46,
"text": "This technique is also very useful for compounds which boil beyond their decomposition temperature at atmospheric pressure and which would therefore be decomposed by any attempt to boil them under atmospheric pressure.",
"title": "Laboratory procedures"
},
{
"paragraph_id": 47,
"text": "Molecular distillation is vacuum distillation below the pressure of 0.01 torr. 0.01 torr is one order of magnitude above high vacuum, where fluids are in the free molecular flow regime, i.e., the mean free path of molecules is comparable to the size of the equipment. The gaseous phase no longer exerts significant pressure on the substance to be evaporated, and consequently, rate of evaporation no longer depends on pressure. That is, because the continuum assumptions of fluid dynamics no longer apply, mass transport is governed by molecular dynamics rather than fluid dynamics. Thus, a short path between the hot surface and the cold surface is necessary, typically by suspending a hot plate covered with a film of feed next to a cold plate with a line of sight in between. Molecular distillation is used industrially for purification of oils.",
"title": "Laboratory procedures"
},
{
"paragraph_id": 48,
"text": "Short path distillation is a distillation technique that involves the distillate travelling a short distance, often only a few centimeters, and is normally done at reduced pressure. A classic example would be a distillation involving the distillate travelling from one glass bulb to another, without the need for a condenser separating the two chambers. This technique is often used for compounds which are unstable at high temperatures or to purify small amounts of compound. The advantage is that the heating temperature can be considerably lower (at reduced pressure) than the boiling point of the liquid at standard pressure, and the distillate only has to travel a short distance before condensing. A short path ensures that little compound is lost on the sides of the apparatus. The Kugelrohr apparatus is a kind of short path distillation method which often contains multiple chambers to collect distillate fractions.",
"title": "Laboratory procedures"
},
{
"paragraph_id": 49,
"text": "Some compounds have high boiling points as well as being air sensitive. A simple vacuum distillation system as exemplified above can be used, whereby the vacuum is replaced with an inert gas after the distillation is complete. However, this is a less satisfactory system if one desires to collect fractions under a reduced pressure. To do this a \"cow\" or \"pig\" adaptor can be added to the end of the condenser, or for better results or for very air sensitive compounds a Perkin triangle apparatus can be used.",
"title": "Laboratory procedures"
},
{
"paragraph_id": 50,
"text": "The Perkin triangle has means via a series of glass or Teflon taps to allows fractions to be isolated from the rest of the still, without the main body of the distillation being removed from either the vacuum or heat source, and thus can remain in a state of reflux. To do this, the sample is first isolated from the vacuum by means of the taps, the vacuum over the sample is then replaced with an inert gas (such as nitrogen or argon) and can then be stoppered and removed. A fresh collection vessel can then be added to the system, evacuated and linked back into the distillation system via the taps to collect a second fraction, and so on, until all fractions have been collected.",
"title": "Laboratory procedures"
},
{
"paragraph_id": 51,
"text": "Zone distillation is a distillation process in a long container with partial melting of refined matter in moving liquid zone and condensation of vapor in the solid phase at condensate pulling in cold area. The process is worked in theory. When zone heater is moving from the top to the bottom of the container then solid condensate with irregular impurity distribution is forming. Then most pure part of the condensate may be extracted as product. The process may be iterated many times by moving (without turnover) the received condensate to the bottom part of the container on the place of refined matter. The irregular impurity distribution in the condensate (that is efficiency of purification) increases with the number of iterations. Zone distillation is the distillation analog of zone recrystallization. Impurity distribution in the condensate is described by known equations of zone recrystallization – with the replacement of the distribution co-efficient k of crystallization - for the separation factor α of distillation.",
"title": "Laboratory procedures"
},
{
"paragraph_id": 52,
"text": "Non-condensable gas can be expelled from the apparatus by the vapor of relatively volatile co-solvent, which spontaneously evaporates during initial pumping, and this can be achieved with regular oil or diaphragm pump.",
"title": "Laboratory procedures"
},
{
"paragraph_id": 53,
"text": "The unit process of evaporation may also be called \"distillation\":",
"title": "Laboratory procedures"
},
{
"paragraph_id": 54,
"text": "Other uses:",
"title": "Laboratory procedures"
},
{
"paragraph_id": 55,
"text": "Interactions between the components of the solution create properties unique to the solution, as most processes entail non-ideal mixtures, where Raoult's law does not hold. Such interactions can result in a constant-boiling azeotrope which behaves as if it were a pure compound (i.e., boils at a single temperature instead of a range). At an azeotrope, the solution contains the given component in the same proportion as the vapor, so that evaporation does not change the purity, and distillation does not effect separation. For example, ethyl alcohol and water form an azeotrope of 95.6% at 78.1 °C.",
"title": "Azeotropic process"
},
{
"paragraph_id": 56,
"text": "If the azeotrope is not considered sufficiently pure for use, there exist some techniques to break the azeotrope to give a pure distillate. This set of techniques are known as azeotropic distillation. Some techniques achieve this by \"jumping\" over the azeotropic composition (by adding another component to create a new azeotrope, or by varying the pressure). Others work by chemically or physically removing or sequestering the impurity. For example, to purify ethanol beyond 95%, a drying agent (or desiccant, such as potassium carbonate) can be added to convert the soluble water into insoluble water of crystallization. Molecular sieves are often used for this purpose as well.",
"title": "Azeotropic process"
},
{
"paragraph_id": 57,
"text": "Immiscible liquids, such as water and toluene, easily form azeotropes. Commonly, these azeotropes are referred to as a low boiling azeotrope because the boiling point of the azeotrope is lower than the boiling point of either pure component. The temperature and composition of the azeotrope is easily predicted from the vapor pressure of the pure components, without use of Raoult's law. The azeotrope is easily broken in a distillation set-up by using a liquid–liquid separator (a decanter) to separate the two liquid layers that are condensed overhead. Only one of the two liquid layers is refluxed to the distillation set-up.",
"title": "Azeotropic process"
},
{
"paragraph_id": 58,
"text": "High boiling azeotropes, such as a 20 percent by weight mixture of hydrochloric acid in water, also exist. As implied by the name, the boiling point of the azeotrope is greater than the boiling point of either pure component.",
"title": "Azeotropic process"
},
{
"paragraph_id": 59,
"text": "To break azeotropic distillations and cross distillation boundaries, such as in the DeRosier problem, it is necessary to increase the composition of the light key in the distillate.",
"title": "Azeotropic process"
},
{
"paragraph_id": 60,
"text": "The boiling points of components in an azeotrope overlap to form a band. By exposing an azeotrope to a vacuum or positive pressure, it's possible to bias the boiling point of one component away from the other by exploiting the differing vapor pressure curves of each; the curves may overlap at the azeotropic point, but are unlikely to remain identical further along the pressure axis to either side of the azeotropic point. When the bias is great enough, the two boiling points no longer overlap and so the azeotropic band disappears.",
"title": "Azeotropic process"
},
{
"paragraph_id": 61,
"text": "This method can remove the need to add other chemicals to a distillation, but it has two potential drawbacks.",
"title": "Azeotropic process"
},
{
"paragraph_id": 62,
"text": "Under negative pressure, power for a vacuum source is needed and the reduced boiling points of the distillates requires that the condenser be run cooler to prevent distillate vapors being lost to the vacuum source. Increased cooling demands will often require additional energy and possibly new equipment or a change of coolant.",
"title": "Azeotropic process"
},
{
"paragraph_id": 63,
"text": "Alternatively, if positive pressures are required, standard glassware can not be used, energy must be used for pressurization and there is a higher chance of side reactions occurring in the distillation, such as decomposition, due to the higher temperatures required to effect boiling.",
"title": "Azeotropic process"
},
{
"paragraph_id": 64,
"text": "A unidirectional distillation will rely on a pressure change in one direction, either positive or negative.",
"title": "Azeotropic process"
},
{
"paragraph_id": 65,
"text": "Pressure-swing distillation is essentially the same as the unidirectional distillation used to break azeotropic mixtures, but here both positive and negative pressures may be employed.",
"title": "Azeotropic process"
},
{
"paragraph_id": 66,
"text": "This improves the selectivity of the distillation and allows a chemist to optimize distillation by avoiding extremes of pressure and temperature that waste energy. This is particularly important in commercial applications.",
"title": "Azeotropic process"
},
{
"paragraph_id": 67,
"text": "One example of the application of pressure-swing distillation is during the industrial purification of ethyl acetate after its catalytic synthesis from ethanol.",
"title": "Azeotropic process"
},
{
"paragraph_id": 68,
"text": "Large scale industrial distillation applications include both batch and continuous fractional, vacuum, azeotropic, extractive, and steam distillation. The most widely used industrial applications of continuous, steady-state fractional distillation are in petroleum refineries, petrochemical and chemical plants and natural gas processing plants.",
"title": "Industrial process"
},
{
"paragraph_id": 69,
"text": "To control and optimize such industrial distillation, a standardized laboratory method, ASTM D86, is established. This test method extends to the atmospheric distillation of petroleum products using a laboratory batch distillation unit to quantitatively determine the boiling range characteristics of petroleum products.",
"title": "Industrial process"
},
{
"paragraph_id": 70,
"text": "Industrial distillation is typically performed in large, vertical cylindrical columns known as distillation towers or distillation columns with diameters ranging from about 0.65 to 16 metres (2 ft 2 in to 52 ft 6 in) and heights ranging from about 6 to 90 metres (20 to 295 ft) or more. When the process feed has a diverse composition, as in distilling crude oil, liquid outlets at intervals up the column allow for the withdrawal of different fractions or products having different boiling points or boiling ranges. The \"lightest\" products (those with the lowest boiling point) exit from the top of the columns and the \"heaviest\" products (those with the highest boiling point) exit from the bottom of the column and are often called the bottoms.",
"title": "Industrial process"
},
{
"paragraph_id": 71,
"text": "Industrial towers use reflux to achieve a more complete separation of products. Reflux refers to the portion of the condensed overhead liquid product from a distillation or fractionation tower that is returned to the upper part of the tower as shown in the schematic diagram of a typical, large-scale industrial distillation tower. Inside the tower, the downflowing reflux liquid provides cooling and condensation of the upflowing vapors thereby increasing the efficiency of the distillation tower. The more reflux that is provided for a given number of theoretical plates, the better the tower's separation of lower boiling materials from higher boiling materials. Alternatively, the more reflux that is provided for a given desired separation, the fewer the number of theoretical plates required. Chemical engineers must choose what combination of reflux rate and number of plates is both economically and physically feasible for the products purified in the distillation column.",
"title": "Industrial process"
},
{
"paragraph_id": 72,
"text": "Such industrial fractionating towers are also used in cryogenic air separation, producing liquid oxygen, liquid nitrogen, and high purity argon. Distillation of chlorosilanes also enables the production of high-purity silicon for use as a semiconductor.",
"title": "Industrial process"
},
{
"paragraph_id": 73,
"text": "Design and operation of a distillation tower depends on the feed and desired products. Given a simple, binary component feed, analytical methods such as the McCabe–Thiele method or the Fenske equation can be used. For a multi-component feed, simulation models are used both for design and operation. Moreover, the efficiencies of the vapor–liquid contact devices (referred to as \"plates\" or \"trays\") used in distillation towers are typically lower than that of a theoretical 100% efficient equilibrium stage. Hence, a distillation tower needs more trays than the number of theoretical vapor–liquid equilibrium stages. A variety of models have been postulated to estimate tray efficiencies.",
"title": "Industrial process"
},
{
"paragraph_id": 74,
"text": "In modern industrial uses, a packing material is used in the column instead of trays when low pressure drops across the column are required. Other factors that favor packing are: vacuum systems, smaller diameter columns, corrosive systems, systems prone to foaming, systems requiring low liquid holdup, and batch distillation. Conversely, factors that favor plate columns are: presence of solids in feed, high liquid rates, large column diameters, complex columns, columns with wide feed composition variation, columns with a chemical reaction, absorption columns, columns limited by foundation weight tolerance, low liquid rate, large turn-down ratio and those processes subject to process surges.",
"title": "Industrial process"
},
{
"paragraph_id": 75,
"text": "This packing material can either be random dumped packing (25–76 millimetres (1–3 in) wide) such as Raschig rings or structured sheet metal. Liquids tend to wet the surface of the packing and the vapors pass across this wetted surface, where mass transfer takes place. Unlike conventional tray distillation in which every tray represents a separate point of vapor–liquid equilibrium, the vapor–liquid equilibrium curve in a packed column is continuous. However, when modeling packed columns, it is useful to compute a number of \"theoretical stages\" to denote the separation efficiency of the packed column with respect to more traditional trays. Differently shaped packings have different surface areas and void space between packings. Both of these factors affect packing performance.",
"title": "Industrial process"
},
{
"paragraph_id": 76,
"text": "Another factor in addition to the packing shape and surface area that affects the performance of random or structured packing is the liquid and vapor distribution entering the packed bed. The number of theoretical stages required to make a given separation is calculated using a specific vapor to liquid ratio. If the liquid and vapor are not evenly distributed across the superficial tower area as it enters the packed bed, the liquid to vapor ratio will not be correct in the packed bed and the required separation will not be achieved. The packing will appear to not be working properly. The height equivalent to a theoretical plate (HETP) will be greater than expected. The problem is not the packing itself but the mal-distribution of the fluids entering the packed bed. Liquid mal-distribution is more frequently the problem than vapor. The design of the liquid distributors used to introduce the feed and reflux to a packed bed is critical to making the packing perform to it maximum efficiency. Methods of evaluating the effectiveness of a liquid distributor to evenly distribute the liquid entering a packed bed can be found in references. Considerable work has been done on this topic by Fractionation Research, Inc. (commonly known as FRI).",
"title": "Industrial process"
},
{
"paragraph_id": 77,
"text": "The goal of multi-effect distillation is to increase the energy efficiency of the process, for use in desalination, or in some cases one stage in the production of ultrapure water. The number of effects is inversely proportional to the kW·h/m of water recovered figure and refers to the volume of water recovered per unit of energy compared with single-effect distillation. One effect is roughly 636 kW·h/m:",
"title": "Industrial process"
},
{
"paragraph_id": 78,
"text": "There are many other types of multi-effect distillation processes, including one referred to as simply multi-effect distillation (MED), in which multiple chambers, with intervening heat exchangers, are employed.",
"title": "Industrial process"
},
{
"paragraph_id": 79,
"text": "Carbohydrate-containing plant materials are allowed to ferment, producing a dilute solution of ethanol in the process. Spirits such as whiskey and rum are prepared by distilling these dilute solutions of ethanol. Components other than ethanol, including water, esters, and other alcohols, are collected in the condensate, which account for the flavor of the beverage. Some of these beverages are then stored in barrels or other containers to acquire more flavor compounds and characteristic flavors.",
"title": "In food processing"
}
] | Distillation, or classical distillation, is the process of separating the components or substances from a liquid mixture by using selective boiling and condensation, usually inside an apparatus known as a still. Dry distillation is the heating of solid materials to produce gaseous products; this may involve chemical changes such as destructive distillation or cracking. Distillation may result in essentially complete separation, or it may be a partial separation that increases the concentration of selected components; in either case, the process exploits differences in the relative volatility of the mixture's components. In industrial applications, distillation is a unit operation of practically universal importance, but is a physical separation process, not a chemical reaction. An installation used for distillation, especially of distilled beverages, is a distillery. Distillation includes the following applications: The distillation of fermented products produces distilled beverages with a high alcohol content or separates other fermentation products of commercial value.
Distillation is an effective and traditional method of desalination.
In the petroleum industry, oil stabilization is a form of partial distillation that reduces the vapor pressure of crude oil, thereby making it safe for storage and transport as well as reducing the atmospheric emissions of volatile hydrocarbons. In midstream operations at oil refineries, fractional distillation is a major class of operation for transforming crude oil into fuels and chemical feed stocks.
Cryogenic distillation leads to the separation of air into its components – notably oxygen, nitrogen, and argon – for industrial use.
In the chemical industry, large amounts of crude liquid products of chemical synthesis are distilled to separate them, either from other products, from impurities, or from unreacted starting materials. | 2001-08-17T16:18:31Z | 2023-10-26T18:17:08Z | [
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8,302 | David Hilbert | David Hilbert (/ˈhɪlbərt/; German: [ˈdaːvɪt ˈhɪlbɐt]; 23 January 1862 – 14 February 1943) was a German mathematician and one of the most influential mathematicians of the 19th and early 20th centuries. Hilbert discovered and developed a broad range of fundamental ideas including invariant theory, the calculus of variations, commutative algebra, algebraic number theory, the foundations of geometry, spectral theory of operators and its application to integral equations, mathematical physics, and the foundations of mathematics (particularly proof theory).
Hilbert adopted and defended Georg Cantor's set theory and transfinite numbers. In 1900, he presented a collection of problems that set a course for mathematical research of the 20th century.
Hilbert and his students contributed to establishing rigor and developed important tools used in modern mathematical physics. Hilbert was one of the founders of proof theory and mathematical logic.
Hilbert, the first of two children and only son of Otto and Maria Therese (Erdtmann) Hilbert, was born in the Province of Prussia, Kingdom of Prussia, either in Königsberg (according to Hilbert's own statement) or in Wehlau (known since 1946 as Znamensk) near Königsberg where his father worked at the time of his birth.
In late 1872, Hilbert entered the Friedrichskolleg Gymnasium (Collegium fridericianum, the same school that Immanuel Kant had attended 140 years before); but, after an unhappy period, he transferred to (late 1879) and graduated from (early 1880) the more science-oriented Wilhelm Gymnasium. Upon graduation, in autumn 1880, Hilbert enrolled at the University of Königsberg, the "Albertina". In early 1882, Hermann Minkowski (two years younger than Hilbert and also a native of Königsberg but had gone to Berlin for three semesters), returned to Königsberg and entered the university. Hilbert developed a lifelong friendship with the shy, gifted Minkowski.
In 1884, Adolf Hurwitz arrived from Göttingen as an Extraordinarius (i.e., an associate professor). An intense and fruitful scientific exchange among the three began, and Minkowski and Hilbert especially would exercise a reciprocal influence over each other at various times in their scientific careers. Hilbert obtained his doctorate in 1885, with a dissertation, written under Ferdinand von Lindemann, titled Über invariante Eigenschaften spezieller binärer Formen, insbesondere der Kugelfunktionen ("On the invariant properties of special binary forms, in particular the spherical harmonic functions").
Hilbert remained at the University of Königsberg as a Privatdozent (senior lecturer) from 1886 to 1895. In 1895, as a result of intervention on his behalf by Felix Klein, he obtained the position of Professor of Mathematics at the University of Göttingen. During the Klein and Hilbert years, Göttingen became the preeminent institution in the mathematical world. He remained there for the rest of his life.
Among Hilbert's students were Hermann Weyl, chess champion Emanuel Lasker, Ernst Zermelo, and Carl Gustav Hempel. John von Neumann was his assistant. At the University of Göttingen, Hilbert was surrounded by a social circle of some of the most important mathematicians of the 20th century, such as Emmy Noether and Alonzo Church.
Among his 69 Ph.D. students in Göttingen were many who later became famous mathematicians, including (with date of thesis): Otto Blumenthal (1898), Felix Bernstein (1901), Hermann Weyl (1908), Richard Courant (1910), Erich Hecke (1910), Hugo Steinhaus (1911), and Wilhelm Ackermann (1925). Between 1902 and 1939 Hilbert was editor of the Mathematische Annalen, the leading mathematical journal of the time. He was elected an International Member of the United States National Academy of Sciences in 1907.
Good, he did not have enough imagination to become a mathematician.
In 1892, Hilbert married Käthe Jerosch (1864–1945), who was the daughter of a Königsberg merchant, "an outspoken young lady with an independence of mind that matched [Hilbert's]." While at Königsberg they had their one child, Franz Hilbert [de] (1893–1969). Franz suffered throughout his life from an undiagnosed mental illness, which was a source of strain on his relationship with his father. After his son was admitted into a psychiatric clinic, Hilbert said, "From now on, I must consider myself as not having a son." His attitude toward Franz brought Käthe considerable sorrow.
Hilbert considered the mathematician Hermann Minkowski to be his "best and truest friend".
Hilbert was baptized and raised a Calvinist in the Prussian Evangelical Church. He later left the Church and became an agnostic. He also argued that mathematical truth was independent of the existence of God or other a priori assumptions. When Galileo Galilei was criticized for failing to stand up for his convictions on the Heliocentric theory, Hilbert objected: "But [Galileo] was not an idiot. Only an idiot could believe that scientific truth needs martyrdom; that may be necessary in religion, but scientific results prove themselves in due time."
Like Albert Einstein, Hilbert had closest contacts with the Berlin Group whose leading founders had studied under Hilbert in Göttingen (Kurt Grelling, Hans Reichenbach and Walter Dubislav).
Around 1925, Hilbert developed pernicious anemia, a then-untreatable vitamin deficiency whose primary symptom is exhaustion; his assistant Eugene Wigner described him as subject to "enormous fatigue" and how he "seemed quite old," and that even after eventually being diagnosed and treated, he "was hardly a scientist after 1925, and certainly not a Hilbert."
Hilbert was elected to the American Philosophical Society in 1932.
Hilbert lived to see the Nazis purge many of the prominent faculty members at University of Göttingen in 1933. Those forced out included Hermann Weyl (who had taken Hilbert's chair when he retired in 1930), Emmy Noether and Edmund Landau. One who had to leave Germany, Paul Bernays, had collaborated with Hilbert in mathematical logic, and co-authored with him the important book Grundlagen der Mathematik (which eventually appeared in two volumes, in 1934 and 1939). This was a sequel to the Hilbert–Ackermann book Principles of Mathematical Logic from 1928. Hermann Weyl's successor was Helmut Hasse.
About a year later, Hilbert attended a banquet and was seated next to the new Minister of Education, Bernhard Rust. Rust asked whether "the Mathematical Institute really suffered so much because of the departure of the Jews." Hilbert replied, "Suffered? It doesn't exist any longer, does it?"
By the time Hilbert died in 1943, the Nazis had nearly completely restaffed the university, as many of the former faculty had either been Jewish or married to Jews. Hilbert's funeral was attended by fewer than a dozen people, only two of whom were fellow academics, among them Arnold Sommerfeld, a theoretical physicist and also a native of Königsberg. News of his death only became known to the wider world several months after he died.
The epitaph on his tombstone in Göttingen consists of the famous lines he spoke at the conclusion of his retirement address to the Society of German Scientists and Physicians on 8 September 1930. The words were given in response to the Latin maxim: "Ignoramus et ignorabimus" or "We do not know and we shall not know":
The day before Hilbert pronounced these phrases at the 1930 annual meeting of the Society of German Scientists and Physicians, Kurt Gödel—in a round table discussion during the Conference on Epistemology held jointly with the Society meetings—tentatively announced the first expression of his incompleteness theorem. Gödel's incompleteness theorems show that even elementary axiomatic systems such as Peano arithmetic are either self-contradicting or contain logical propositions that are impossible to prove or disprove within that system.
Hilbert's first work on invariant functions led him to the demonstration in 1888 of his famous finiteness theorem. Twenty years earlier, Paul Gordan had demonstrated the theorem of the finiteness of generators for binary forms using a complex computational approach. Attempts to generalize his method to functions with more than two variables failed because of the enormous difficulty of the calculations involved. To solve what had become known in some circles as Gordan's Problem, Hilbert realized that it was necessary to take a completely different path. As a result, he demonstrated Hilbert's basis theorem, showing the existence of a finite set of generators, for the invariants of quantics in any number of variables, but in an abstract form. That is, while demonstrating the existence of such a set, it was not a constructive proof—it did not display "an object"—but rather, it was an existence proof and relied on use of the law of excluded middle in an infinite extension.
Hilbert sent his results to the Mathematische Annalen. Gordan, the house expert on the theory of invariants for the Mathematische Annalen, could not appreciate the revolutionary nature of Hilbert's theorem and rejected the article, criticizing the exposition because it was insufficiently comprehensive. His comment was:
Klein, on the other hand, recognized the importance of the work, and guaranteed that it would be published without any alterations. Encouraged by Klein, Hilbert extended his method in a second article, providing estimations on the maximum degree of the minimum set of generators, and he sent it once more to the Annalen. After having read the manuscript, Klein wrote to him, saying:
Without doubt this is the most important work on general algebra that the Annalen has ever published.
Later, after the usefulness of Hilbert's method was universally recognized, Gordan himself would say:
I have convinced myself that even theology has its merits.
For all his successes, the nature of his proof created more trouble than Hilbert could have imagined. Although Kronecker had conceded, Hilbert would later respond to others' similar criticisms that "many different constructions are subsumed under one fundamental idea"—in other words (to quote Reid): "Through a proof of existence, Hilbert had been able to obtain a construction"; "the proof" (i.e. the symbols on the page) was "the object". Not all were convinced. While Kronecker would die soon afterwards, his constructivist philosophy would continue with the young Brouwer and his developing intuitionist "school", much to Hilbert's torment in his later years. Indeed, Hilbert would lose his "gifted pupil" Weyl to intuitionism—"Hilbert was disturbed by his former student's fascination with the ideas of Brouwer, which aroused in Hilbert the memory of Kronecker". Brouwer the intuitionist in particular opposed the use of the Law of Excluded Middle over infinite sets (as Hilbert had used it). Hilbert responded:
Taking the Principle of the Excluded Middle from the mathematician ... is the same as ... prohibiting the boxer the use of his fists.
The text Grundlagen der Geometrie (tr.: Foundations of Geometry) published by Hilbert in 1899 proposes a formal set, called Hilbert's axioms, substituting for the traditional axioms of Euclid. They avoid weaknesses identified in those of Euclid, whose works at the time were still used textbook-fashion. It is difficult to specify the axioms used by Hilbert without referring to the publication history of the Grundlagen since Hilbert changed and modified them several times. The original monograph was quickly followed by a French translation, in which Hilbert added V.2, the Completeness Axiom. An English translation, authorized by Hilbert, was made by E.J. Townsend and copyrighted in 1902. This translation incorporated the changes made in the French translation and so is considered to be a translation of the 2nd edition. Hilbert continued to make changes in the text and several editions appeared in German. The 7th edition was the last to appear in Hilbert's lifetime. New editions followed the 7th, but the main text was essentially not revised.
Hilbert's approach signaled the shift to the modern axiomatic method. In this, Hilbert was anticipated by Moritz Pasch's work from 1882. Axioms are not taken as self-evident truths. Geometry may treat things, about which we have powerful intuitions, but it is not necessary to assign any explicit meaning to the undefined concepts. The elements, such as point, line, plane, and others, could be substituted, as Hilbert is reported to have said to Schoenflies and Kötter, by tables, chairs, glasses of beer and other such objects. It is their defined relationships that are discussed.
Hilbert first enumerates the undefined concepts: point, line, plane, lying on (a relation between points and lines, points and planes, and lines and planes), betweenness, congruence of pairs of points (line segments), and congruence of angles. The axioms unify both the plane geometry and solid geometry of Euclid in a single system.
Hilbert put forth the most influential list consisting of 23 unsolved problems at the International Congress of Mathematicians in Paris in 1900. This is generally reckoned as the most successful and deeply considered compilation of open problems ever to be produced by an individual mathematician.
After re-working the foundations of classical geometry, Hilbert could have extrapolated to the rest of mathematics. His approach differed, however, from the later "foundationalist" Russell–Whitehead or "encyclopedist" Nicolas Bourbaki, and from his contemporary Giuseppe Peano. The mathematical community as a whole could engage in problems of which he had identified as crucial aspects of important areas of mathematics.
The problem set was launched as a talk "The Problems of Mathematics" presented during the course of the Second International Congress of Mathematicians held in Paris. The introduction of the speech that Hilbert gave said:
Who among us would not be happy to lift the veil behind which is hidden the future; to gaze at the coming developments of our science and at the secrets of its development in the centuries to come? What will be the ends toward which the spirit of future generations of mathematicians will tend? What methods, what new facts will the new century reveal in the vast and rich field of mathematical thought?
He presented fewer than half the problems at the Congress, which were published in the acts of the Congress. In a subsequent publication, he extended the panorama, and arrived at the formulation of the now-canonical 23 Problems of Hilbert. See also Hilbert's twenty-fourth problem. The full text is important, since the exegesis of the questions still can be a matter of inevitable debate, whenever it is asked how many have been solved.
Some of these were solved within a short time. Others have been discussed throughout the 20th century, with a few now taken to be unsuitably open-ended to come to closure. Some continue to remain challenges.
In an account that had become standard by the mid-century, Hilbert's problem set was also a kind of manifesto that opened the way for the development of the formalist school, one of three major schools of mathematics of the 20th century. According to the formalist, mathematics is manipulation of symbols according to agreed upon formal rules. It is therefore an autonomous activity of thought. There is, however, room to doubt whether Hilbert's own views were simplistically formalist in this sense.
In 1920, Hilbert proposed a research project in metamathematics that became known as Hilbert's program. He wanted mathematics to be formulated on a solid and complete logical foundation. He believed that in principle this could be done by showing that:
He seems to have had both technical and philosophical reasons for formulating this proposal. It affirmed his dislike of what had become known as the ignorabimus, still an active issue in his time in German thought, and traced back in that formulation to Emil du Bois-Reymond.
This program is still recognizable in the most popular philosophy of mathematics, where it is usually called formalism. For example, the Bourbaki group adopted a watered-down and selective version of it as adequate to the requirements of their twin projects of (a) writing encyclopedic foundational works, and (b) supporting the axiomatic method as a research tool. This approach has been successful and influential in relation with Hilbert's work in algebra and functional analysis, but has failed to engage in the same way with his interests in physics and logic.
Hilbert wrote in 1919:
We are not speaking here of arbitrariness in any sense. Mathematics is not like a game whose tasks are determined by arbitrarily stipulated rules. Rather, it is a conceptual system possessing internal necessity that can only be so and by no means otherwise.
Hilbert published his views on the foundations of mathematics in the 2-volume work, Grundlagen der Mathematik.
Hilbert and the mathematicians who worked with him in his enterprise were committed to the project. His attempt to support axiomatized mathematics with definitive principles, which could banish theoretical uncertainties, ended in failure.
Gödel demonstrated that any non-contradictory formal system, which was comprehensive enough to include at least arithmetic, cannot demonstrate its completeness by way of its own axioms. In 1931 his incompleteness theorem showed that Hilbert's grand plan was impossible as stated. The second point cannot in any reasonable way be combined with the first point, as long as the axiom system is genuinely finitary.
Nevertheless, the subsequent achievements of proof theory at the very least clarified consistency as it relates to theories of central concern to mathematicians. Hilbert's work had started logic on this course of clarification; the need to understand Gödel's work then led to the development of recursion theory and then mathematical logic as an autonomous discipline in the 1930s. The basis for later theoretical computer science, in the work of Alonzo Church and Alan Turing, also grew directly out of this "debate".
Around 1909, Hilbert dedicated himself to the study of differential and integral equations; his work had direct consequences for important parts of modern functional analysis. In order to carry out these studies, Hilbert introduced the concept of an infinite dimensional Euclidean space, later called Hilbert space. His work in this part of analysis provided the basis for important contributions to the mathematics of physics in the next two decades, though from an unanticipated direction. Later on, Stefan Banach amplified the concept, defining Banach spaces. Hilbert spaces are an important class of objects in the area of functional analysis, particularly of the spectral theory of self-adjoint linear operators, that grew up around it during the 20th century.
Until 1912, Hilbert was almost exclusively a pure mathematician. When planning a visit from Bonn, where he was immersed in studying physics, his fellow mathematician and friend Hermann Minkowski joked he had to spend 10 days in quarantine before being able to visit Hilbert. In fact, Minkowski seems responsible for most of Hilbert's physics investigations prior to 1912, including their joint seminar on the subject in 1905.
In 1912, three years after his friend's death, Hilbert turned his focus to the subject almost exclusively. He arranged to have a "physics tutor" for himself. He started studying kinetic gas theory and moved on to elementary radiation theory and the molecular theory of matter. Even after the war started in 1914, he continued seminars and classes where the works of Albert Einstein and others were followed closely.
By 1907, Einstein had framed the fundamentals of the theory of gravity, but then struggled for nearly 8 years to put the theory into its final form. By early summer 1915, Hilbert's interest in physics had focused on general relativity, and he invited Einstein to Göttingen to deliver a week of lectures on the subject. Einstein received an enthusiastic reception at Göttingen. Over the summer, Einstein learned that Hilbert was also working on the field equations and redoubled his own efforts. During November 1915, Einstein published several papers culminating in The Field Equations of Gravitation (see Einstein field equations). Nearly simultaneously, Hilbert published "The Foundations of Physics", an axiomatic derivation of the field equations (see Einstein–Hilbert action). Hilbert fully credited Einstein as the originator of the theory and no public priority dispute concerning the field equations ever arose between the two men during their lives. See more at priority.
Additionally, Hilbert's work anticipated and assisted several advances in the mathematical formulation of quantum mechanics. His work was a key aspect of Hermann Weyl and John von Neumann's work on the mathematical equivalence of Werner Heisenberg's matrix mechanics and Erwin Schrödinger's wave equation, and his namesake Hilbert space plays an important part in quantum theory. In 1926, von Neumann showed that, if quantum states were understood as vectors in Hilbert space, they would correspond with both Schrödinger's wave function theory and Heisenberg's matrices.
Throughout this immersion in physics, Hilbert worked on putting rigor into the mathematics of physics. While highly dependent on higher mathematics, physicists tended to be "sloppy" with it. To a pure mathematician like Hilbert, this was both ugly, and difficult to understand. As he began to understand physics and how physicists were using mathematics, he developed a coherent mathematical theory for what he found – most importantly in the area of integral equations. When his colleague Richard Courant wrote the now classic Methoden der mathematischen Physik (Methods of Mathematical Physics) including some of Hilbert's ideas, he added Hilbert's name as author even though Hilbert had not directly contributed to the writing. Hilbert said "Physics is too hard for physicists", implying that the necessary mathematics was generally beyond them; the Courant-Hilbert book made it easier for them.
Hilbert unified the field of algebraic number theory with his 1897 treatise Zahlbericht (literally "report on numbers"). He also resolved a significant number-theory problem formulated by Waring in 1770. As with the finiteness theorem, he used an existence proof that shows there must be solutions for the problem rather than providing a mechanism to produce the answers. He then had little more to publish on the subject; but the emergence of Hilbert modular forms in the dissertation of a student means his name is further attached to a major area.
He made a series of conjectures on class field theory. The concepts were highly influential, and his own contribution lives on in the names of the Hilbert class field and of the Hilbert symbol of local class field theory. Results were mostly proved by 1930, after work by Teiji Takagi.
Hilbert did not work in the central areas of analytic number theory, but his name has become known for the Hilbert–Pólya conjecture, for reasons that are anecdotal.
His collected works (Gesammelte Abhandlungen) have been published several times. The original versions of his papers contained "many technical errors of varying degree"; when the collection was first published, the errors were corrected and it was found that this could be done without major changes in the statements of the theorems, with one exception—a claimed proof of the continuum hypothesis. The errors were nonetheless so numerous and significant that it took Olga Taussky-Todd three years to make the corrections. | [
{
"paragraph_id": 0,
"text": "David Hilbert (/ˈhɪlbərt/; German: [ˈdaːvɪt ˈhɪlbɐt]; 23 January 1862 – 14 February 1943) was a German mathematician and one of the most influential mathematicians of the 19th and early 20th centuries. Hilbert discovered and developed a broad range of fundamental ideas including invariant theory, the calculus of variations, commutative algebra, algebraic number theory, the foundations of geometry, spectral theory of operators and its application to integral equations, mathematical physics, and the foundations of mathematics (particularly proof theory).",
"title": ""
},
{
"paragraph_id": 1,
"text": "Hilbert adopted and defended Georg Cantor's set theory and transfinite numbers. In 1900, he presented a collection of problems that set a course for mathematical research of the 20th century.",
"title": ""
},
{
"paragraph_id": 2,
"text": "Hilbert and his students contributed to establishing rigor and developed important tools used in modern mathematical physics. Hilbert was one of the founders of proof theory and mathematical logic.",
"title": ""
},
{
"paragraph_id": 3,
"text": "Hilbert, the first of two children and only son of Otto and Maria Therese (Erdtmann) Hilbert, was born in the Province of Prussia, Kingdom of Prussia, either in Königsberg (according to Hilbert's own statement) or in Wehlau (known since 1946 as Znamensk) near Königsberg where his father worked at the time of his birth.",
"title": "Life"
},
{
"paragraph_id": 4,
"text": "In late 1872, Hilbert entered the Friedrichskolleg Gymnasium (Collegium fridericianum, the same school that Immanuel Kant had attended 140 years before); but, after an unhappy period, he transferred to (late 1879) and graduated from (early 1880) the more science-oriented Wilhelm Gymnasium. Upon graduation, in autumn 1880, Hilbert enrolled at the University of Königsberg, the \"Albertina\". In early 1882, Hermann Minkowski (two years younger than Hilbert and also a native of Königsberg but had gone to Berlin for three semesters), returned to Königsberg and entered the university. Hilbert developed a lifelong friendship with the shy, gifted Minkowski.",
"title": "Life"
},
{
"paragraph_id": 5,
"text": "In 1884, Adolf Hurwitz arrived from Göttingen as an Extraordinarius (i.e., an associate professor). An intense and fruitful scientific exchange among the three began, and Minkowski and Hilbert especially would exercise a reciprocal influence over each other at various times in their scientific careers. Hilbert obtained his doctorate in 1885, with a dissertation, written under Ferdinand von Lindemann, titled Über invariante Eigenschaften spezieller binärer Formen, insbesondere der Kugelfunktionen (\"On the invariant properties of special binary forms, in particular the spherical harmonic functions\").",
"title": "Life"
},
{
"paragraph_id": 6,
"text": "Hilbert remained at the University of Königsberg as a Privatdozent (senior lecturer) from 1886 to 1895. In 1895, as a result of intervention on his behalf by Felix Klein, he obtained the position of Professor of Mathematics at the University of Göttingen. During the Klein and Hilbert years, Göttingen became the preeminent institution in the mathematical world. He remained there for the rest of his life.",
"title": "Life"
},
{
"paragraph_id": 7,
"text": "Among Hilbert's students were Hermann Weyl, chess champion Emanuel Lasker, Ernst Zermelo, and Carl Gustav Hempel. John von Neumann was his assistant. At the University of Göttingen, Hilbert was surrounded by a social circle of some of the most important mathematicians of the 20th century, such as Emmy Noether and Alonzo Church.",
"title": "Life"
},
{
"paragraph_id": 8,
"text": "Among his 69 Ph.D. students in Göttingen were many who later became famous mathematicians, including (with date of thesis): Otto Blumenthal (1898), Felix Bernstein (1901), Hermann Weyl (1908), Richard Courant (1910), Erich Hecke (1910), Hugo Steinhaus (1911), and Wilhelm Ackermann (1925). Between 1902 and 1939 Hilbert was editor of the Mathematische Annalen, the leading mathematical journal of the time. He was elected an International Member of the United States National Academy of Sciences in 1907.",
"title": "Life"
},
{
"paragraph_id": 9,
"text": "Good, he did not have enough imagination to become a mathematician.",
"title": "Life"
},
{
"paragraph_id": 10,
"text": "In 1892, Hilbert married Käthe Jerosch (1864–1945), who was the daughter of a Königsberg merchant, \"an outspoken young lady with an independence of mind that matched [Hilbert's].\" While at Königsberg they had their one child, Franz Hilbert [de] (1893–1969). Franz suffered throughout his life from an undiagnosed mental illness, which was a source of strain on his relationship with his father. After his son was admitted into a psychiatric clinic, Hilbert said, \"From now on, I must consider myself as not having a son.\" His attitude toward Franz brought Käthe considerable sorrow.",
"title": "Life"
},
{
"paragraph_id": 11,
"text": "Hilbert considered the mathematician Hermann Minkowski to be his \"best and truest friend\".",
"title": "Life"
},
{
"paragraph_id": 12,
"text": "Hilbert was baptized and raised a Calvinist in the Prussian Evangelical Church. He later left the Church and became an agnostic. He also argued that mathematical truth was independent of the existence of God or other a priori assumptions. When Galileo Galilei was criticized for failing to stand up for his convictions on the Heliocentric theory, Hilbert objected: \"But [Galileo] was not an idiot. Only an idiot could believe that scientific truth needs martyrdom; that may be necessary in religion, but scientific results prove themselves in due time.\"",
"title": "Life"
},
{
"paragraph_id": 13,
"text": "Like Albert Einstein, Hilbert had closest contacts with the Berlin Group whose leading founders had studied under Hilbert in Göttingen (Kurt Grelling, Hans Reichenbach and Walter Dubislav).",
"title": "Life"
},
{
"paragraph_id": 14,
"text": "Around 1925, Hilbert developed pernicious anemia, a then-untreatable vitamin deficiency whose primary symptom is exhaustion; his assistant Eugene Wigner described him as subject to \"enormous fatigue\" and how he \"seemed quite old,\" and that even after eventually being diagnosed and treated, he \"was hardly a scientist after 1925, and certainly not a Hilbert.\"",
"title": "Life"
},
{
"paragraph_id": 15,
"text": "Hilbert was elected to the American Philosophical Society in 1932.",
"title": "Life"
},
{
"paragraph_id": 16,
"text": "Hilbert lived to see the Nazis purge many of the prominent faculty members at University of Göttingen in 1933. Those forced out included Hermann Weyl (who had taken Hilbert's chair when he retired in 1930), Emmy Noether and Edmund Landau. One who had to leave Germany, Paul Bernays, had collaborated with Hilbert in mathematical logic, and co-authored with him the important book Grundlagen der Mathematik (which eventually appeared in two volumes, in 1934 and 1939). This was a sequel to the Hilbert–Ackermann book Principles of Mathematical Logic from 1928. Hermann Weyl's successor was Helmut Hasse.",
"title": "Life"
},
{
"paragraph_id": 17,
"text": "About a year later, Hilbert attended a banquet and was seated next to the new Minister of Education, Bernhard Rust. Rust asked whether \"the Mathematical Institute really suffered so much because of the departure of the Jews.\" Hilbert replied, \"Suffered? It doesn't exist any longer, does it?\"",
"title": "Life"
},
{
"paragraph_id": 18,
"text": "By the time Hilbert died in 1943, the Nazis had nearly completely restaffed the university, as many of the former faculty had either been Jewish or married to Jews. Hilbert's funeral was attended by fewer than a dozen people, only two of whom were fellow academics, among them Arnold Sommerfeld, a theoretical physicist and also a native of Königsberg. News of his death only became known to the wider world several months after he died.",
"title": "Life"
},
{
"paragraph_id": 19,
"text": "The epitaph on his tombstone in Göttingen consists of the famous lines he spoke at the conclusion of his retirement address to the Society of German Scientists and Physicians on 8 September 1930. The words were given in response to the Latin maxim: \"Ignoramus et ignorabimus\" or \"We do not know and we shall not know\":",
"title": "Life"
},
{
"paragraph_id": 20,
"text": "The day before Hilbert pronounced these phrases at the 1930 annual meeting of the Society of German Scientists and Physicians, Kurt Gödel—in a round table discussion during the Conference on Epistemology held jointly with the Society meetings—tentatively announced the first expression of his incompleteness theorem. Gödel's incompleteness theorems show that even elementary axiomatic systems such as Peano arithmetic are either self-contradicting or contain logical propositions that are impossible to prove or disprove within that system.",
"title": "Life"
},
{
"paragraph_id": 21,
"text": "Hilbert's first work on invariant functions led him to the demonstration in 1888 of his famous finiteness theorem. Twenty years earlier, Paul Gordan had demonstrated the theorem of the finiteness of generators for binary forms using a complex computational approach. Attempts to generalize his method to functions with more than two variables failed because of the enormous difficulty of the calculations involved. To solve what had become known in some circles as Gordan's Problem, Hilbert realized that it was necessary to take a completely different path. As a result, he demonstrated Hilbert's basis theorem, showing the existence of a finite set of generators, for the invariants of quantics in any number of variables, but in an abstract form. That is, while demonstrating the existence of such a set, it was not a constructive proof—it did not display \"an object\"—but rather, it was an existence proof and relied on use of the law of excluded middle in an infinite extension.",
"title": "Contributions to mathematics and physics"
},
{
"paragraph_id": 22,
"text": "Hilbert sent his results to the Mathematische Annalen. Gordan, the house expert on the theory of invariants for the Mathematische Annalen, could not appreciate the revolutionary nature of Hilbert's theorem and rejected the article, criticizing the exposition because it was insufficiently comprehensive. His comment was:",
"title": "Contributions to mathematics and physics"
},
{
"paragraph_id": 23,
"text": "Klein, on the other hand, recognized the importance of the work, and guaranteed that it would be published without any alterations. Encouraged by Klein, Hilbert extended his method in a second article, providing estimations on the maximum degree of the minimum set of generators, and he sent it once more to the Annalen. After having read the manuscript, Klein wrote to him, saying:",
"title": "Contributions to mathematics and physics"
},
{
"paragraph_id": 24,
"text": "Without doubt this is the most important work on general algebra that the Annalen has ever published.",
"title": "Contributions to mathematics and physics"
},
{
"paragraph_id": 25,
"text": "Later, after the usefulness of Hilbert's method was universally recognized, Gordan himself would say:",
"title": "Contributions to mathematics and physics"
},
{
"paragraph_id": 26,
"text": "I have convinced myself that even theology has its merits.",
"title": "Contributions to mathematics and physics"
},
{
"paragraph_id": 27,
"text": "For all his successes, the nature of his proof created more trouble than Hilbert could have imagined. Although Kronecker had conceded, Hilbert would later respond to others' similar criticisms that \"many different constructions are subsumed under one fundamental idea\"—in other words (to quote Reid): \"Through a proof of existence, Hilbert had been able to obtain a construction\"; \"the proof\" (i.e. the symbols on the page) was \"the object\". Not all were convinced. While Kronecker would die soon afterwards, his constructivist philosophy would continue with the young Brouwer and his developing intuitionist \"school\", much to Hilbert's torment in his later years. Indeed, Hilbert would lose his \"gifted pupil\" Weyl to intuitionism—\"Hilbert was disturbed by his former student's fascination with the ideas of Brouwer, which aroused in Hilbert the memory of Kronecker\". Brouwer the intuitionist in particular opposed the use of the Law of Excluded Middle over infinite sets (as Hilbert had used it). Hilbert responded:",
"title": "Contributions to mathematics and physics"
},
{
"paragraph_id": 28,
"text": "Taking the Principle of the Excluded Middle from the mathematician ... is the same as ... prohibiting the boxer the use of his fists.",
"title": "Contributions to mathematics and physics"
},
{
"paragraph_id": 29,
"text": "The text Grundlagen der Geometrie (tr.: Foundations of Geometry) published by Hilbert in 1899 proposes a formal set, called Hilbert's axioms, substituting for the traditional axioms of Euclid. They avoid weaknesses identified in those of Euclid, whose works at the time were still used textbook-fashion. It is difficult to specify the axioms used by Hilbert without referring to the publication history of the Grundlagen since Hilbert changed and modified them several times. The original monograph was quickly followed by a French translation, in which Hilbert added V.2, the Completeness Axiom. An English translation, authorized by Hilbert, was made by E.J. Townsend and copyrighted in 1902. This translation incorporated the changes made in the French translation and so is considered to be a translation of the 2nd edition. Hilbert continued to make changes in the text and several editions appeared in German. The 7th edition was the last to appear in Hilbert's lifetime. New editions followed the 7th, but the main text was essentially not revised.",
"title": "Contributions to mathematics and physics"
},
{
"paragraph_id": 30,
"text": "Hilbert's approach signaled the shift to the modern axiomatic method. In this, Hilbert was anticipated by Moritz Pasch's work from 1882. Axioms are not taken as self-evident truths. Geometry may treat things, about which we have powerful intuitions, but it is not necessary to assign any explicit meaning to the undefined concepts. The elements, such as point, line, plane, and others, could be substituted, as Hilbert is reported to have said to Schoenflies and Kötter, by tables, chairs, glasses of beer and other such objects. It is their defined relationships that are discussed.",
"title": "Contributions to mathematics and physics"
},
{
"paragraph_id": 31,
"text": "Hilbert first enumerates the undefined concepts: point, line, plane, lying on (a relation between points and lines, points and planes, and lines and planes), betweenness, congruence of pairs of points (line segments), and congruence of angles. The axioms unify both the plane geometry and solid geometry of Euclid in a single system.",
"title": "Contributions to mathematics and physics"
},
{
"paragraph_id": 32,
"text": "Hilbert put forth the most influential list consisting of 23 unsolved problems at the International Congress of Mathematicians in Paris in 1900. This is generally reckoned as the most successful and deeply considered compilation of open problems ever to be produced by an individual mathematician.",
"title": "Contributions to mathematics and physics"
},
{
"paragraph_id": 33,
"text": "After re-working the foundations of classical geometry, Hilbert could have extrapolated to the rest of mathematics. His approach differed, however, from the later \"foundationalist\" Russell–Whitehead or \"encyclopedist\" Nicolas Bourbaki, and from his contemporary Giuseppe Peano. The mathematical community as a whole could engage in problems of which he had identified as crucial aspects of important areas of mathematics.",
"title": "Contributions to mathematics and physics"
},
{
"paragraph_id": 34,
"text": "The problem set was launched as a talk \"The Problems of Mathematics\" presented during the course of the Second International Congress of Mathematicians held in Paris. The introduction of the speech that Hilbert gave said:",
"title": "Contributions to mathematics and physics"
},
{
"paragraph_id": 35,
"text": "Who among us would not be happy to lift the veil behind which is hidden the future; to gaze at the coming developments of our science and at the secrets of its development in the centuries to come? What will be the ends toward which the spirit of future generations of mathematicians will tend? What methods, what new facts will the new century reveal in the vast and rich field of mathematical thought?",
"title": "Contributions to mathematics and physics"
},
{
"paragraph_id": 36,
"text": "He presented fewer than half the problems at the Congress, which were published in the acts of the Congress. In a subsequent publication, he extended the panorama, and arrived at the formulation of the now-canonical 23 Problems of Hilbert. See also Hilbert's twenty-fourth problem. The full text is important, since the exegesis of the questions still can be a matter of inevitable debate, whenever it is asked how many have been solved.",
"title": "Contributions to mathematics and physics"
},
{
"paragraph_id": 37,
"text": "Some of these were solved within a short time. Others have been discussed throughout the 20th century, with a few now taken to be unsuitably open-ended to come to closure. Some continue to remain challenges.",
"title": "Contributions to mathematics and physics"
},
{
"paragraph_id": 38,
"text": "In an account that had become standard by the mid-century, Hilbert's problem set was also a kind of manifesto that opened the way for the development of the formalist school, one of three major schools of mathematics of the 20th century. According to the formalist, mathematics is manipulation of symbols according to agreed upon formal rules. It is therefore an autonomous activity of thought. There is, however, room to doubt whether Hilbert's own views were simplistically formalist in this sense.",
"title": "Contributions to mathematics and physics"
},
{
"paragraph_id": 39,
"text": "In 1920, Hilbert proposed a research project in metamathematics that became known as Hilbert's program. He wanted mathematics to be formulated on a solid and complete logical foundation. He believed that in principle this could be done by showing that:",
"title": "Contributions to mathematics and physics"
},
{
"paragraph_id": 40,
"text": "He seems to have had both technical and philosophical reasons for formulating this proposal. It affirmed his dislike of what had become known as the ignorabimus, still an active issue in his time in German thought, and traced back in that formulation to Emil du Bois-Reymond.",
"title": "Contributions to mathematics and physics"
},
{
"paragraph_id": 41,
"text": "This program is still recognizable in the most popular philosophy of mathematics, where it is usually called formalism. For example, the Bourbaki group adopted a watered-down and selective version of it as adequate to the requirements of their twin projects of (a) writing encyclopedic foundational works, and (b) supporting the axiomatic method as a research tool. This approach has been successful and influential in relation with Hilbert's work in algebra and functional analysis, but has failed to engage in the same way with his interests in physics and logic.",
"title": "Contributions to mathematics and physics"
},
{
"paragraph_id": 42,
"text": "Hilbert wrote in 1919:",
"title": "Contributions to mathematics and physics"
},
{
"paragraph_id": 43,
"text": "We are not speaking here of arbitrariness in any sense. Mathematics is not like a game whose tasks are determined by arbitrarily stipulated rules. Rather, it is a conceptual system possessing internal necessity that can only be so and by no means otherwise.",
"title": "Contributions to mathematics and physics"
},
{
"paragraph_id": 44,
"text": "Hilbert published his views on the foundations of mathematics in the 2-volume work, Grundlagen der Mathematik.",
"title": "Contributions to mathematics and physics"
},
{
"paragraph_id": 45,
"text": "Hilbert and the mathematicians who worked with him in his enterprise were committed to the project. His attempt to support axiomatized mathematics with definitive principles, which could banish theoretical uncertainties, ended in failure.",
"title": "Contributions to mathematics and physics"
},
{
"paragraph_id": 46,
"text": "Gödel demonstrated that any non-contradictory formal system, which was comprehensive enough to include at least arithmetic, cannot demonstrate its completeness by way of its own axioms. In 1931 his incompleteness theorem showed that Hilbert's grand plan was impossible as stated. The second point cannot in any reasonable way be combined with the first point, as long as the axiom system is genuinely finitary.",
"title": "Contributions to mathematics and physics"
},
{
"paragraph_id": 47,
"text": "Nevertheless, the subsequent achievements of proof theory at the very least clarified consistency as it relates to theories of central concern to mathematicians. Hilbert's work had started logic on this course of clarification; the need to understand Gödel's work then led to the development of recursion theory and then mathematical logic as an autonomous discipline in the 1930s. The basis for later theoretical computer science, in the work of Alonzo Church and Alan Turing, also grew directly out of this \"debate\".",
"title": "Contributions to mathematics and physics"
},
{
"paragraph_id": 48,
"text": "Around 1909, Hilbert dedicated himself to the study of differential and integral equations; his work had direct consequences for important parts of modern functional analysis. In order to carry out these studies, Hilbert introduced the concept of an infinite dimensional Euclidean space, later called Hilbert space. His work in this part of analysis provided the basis for important contributions to the mathematics of physics in the next two decades, though from an unanticipated direction. Later on, Stefan Banach amplified the concept, defining Banach spaces. Hilbert spaces are an important class of objects in the area of functional analysis, particularly of the spectral theory of self-adjoint linear operators, that grew up around it during the 20th century.",
"title": "Contributions to mathematics and physics"
},
{
"paragraph_id": 49,
"text": "Until 1912, Hilbert was almost exclusively a pure mathematician. When planning a visit from Bonn, where he was immersed in studying physics, his fellow mathematician and friend Hermann Minkowski joked he had to spend 10 days in quarantine before being able to visit Hilbert. In fact, Minkowski seems responsible for most of Hilbert's physics investigations prior to 1912, including their joint seminar on the subject in 1905.",
"title": "Contributions to mathematics and physics"
},
{
"paragraph_id": 50,
"text": "In 1912, three years after his friend's death, Hilbert turned his focus to the subject almost exclusively. He arranged to have a \"physics tutor\" for himself. He started studying kinetic gas theory and moved on to elementary radiation theory and the molecular theory of matter. Even after the war started in 1914, he continued seminars and classes where the works of Albert Einstein and others were followed closely.",
"title": "Contributions to mathematics and physics"
},
{
"paragraph_id": 51,
"text": "By 1907, Einstein had framed the fundamentals of the theory of gravity, but then struggled for nearly 8 years to put the theory into its final form. By early summer 1915, Hilbert's interest in physics had focused on general relativity, and he invited Einstein to Göttingen to deliver a week of lectures on the subject. Einstein received an enthusiastic reception at Göttingen. Over the summer, Einstein learned that Hilbert was also working on the field equations and redoubled his own efforts. During November 1915, Einstein published several papers culminating in The Field Equations of Gravitation (see Einstein field equations). Nearly simultaneously, Hilbert published \"The Foundations of Physics\", an axiomatic derivation of the field equations (see Einstein–Hilbert action). Hilbert fully credited Einstein as the originator of the theory and no public priority dispute concerning the field equations ever arose between the two men during their lives. See more at priority.",
"title": "Contributions to mathematics and physics"
},
{
"paragraph_id": 52,
"text": "Additionally, Hilbert's work anticipated and assisted several advances in the mathematical formulation of quantum mechanics. His work was a key aspect of Hermann Weyl and John von Neumann's work on the mathematical equivalence of Werner Heisenberg's matrix mechanics and Erwin Schrödinger's wave equation, and his namesake Hilbert space plays an important part in quantum theory. In 1926, von Neumann showed that, if quantum states were understood as vectors in Hilbert space, they would correspond with both Schrödinger's wave function theory and Heisenberg's matrices.",
"title": "Contributions to mathematics and physics"
},
{
"paragraph_id": 53,
"text": "Throughout this immersion in physics, Hilbert worked on putting rigor into the mathematics of physics. While highly dependent on higher mathematics, physicists tended to be \"sloppy\" with it. To a pure mathematician like Hilbert, this was both ugly, and difficult to understand. As he began to understand physics and how physicists were using mathematics, he developed a coherent mathematical theory for what he found – most importantly in the area of integral equations. When his colleague Richard Courant wrote the now classic Methoden der mathematischen Physik (Methods of Mathematical Physics) including some of Hilbert's ideas, he added Hilbert's name as author even though Hilbert had not directly contributed to the writing. Hilbert said \"Physics is too hard for physicists\", implying that the necessary mathematics was generally beyond them; the Courant-Hilbert book made it easier for them.",
"title": "Contributions to mathematics and physics"
},
{
"paragraph_id": 54,
"text": "Hilbert unified the field of algebraic number theory with his 1897 treatise Zahlbericht (literally \"report on numbers\"). He also resolved a significant number-theory problem formulated by Waring in 1770. As with the finiteness theorem, he used an existence proof that shows there must be solutions for the problem rather than providing a mechanism to produce the answers. He then had little more to publish on the subject; but the emergence of Hilbert modular forms in the dissertation of a student means his name is further attached to a major area.",
"title": "Contributions to mathematics and physics"
},
{
"paragraph_id": 55,
"text": "He made a series of conjectures on class field theory. The concepts were highly influential, and his own contribution lives on in the names of the Hilbert class field and of the Hilbert symbol of local class field theory. Results were mostly proved by 1930, after work by Teiji Takagi.",
"title": "Contributions to mathematics and physics"
},
{
"paragraph_id": 56,
"text": "Hilbert did not work in the central areas of analytic number theory, but his name has become known for the Hilbert–Pólya conjecture, for reasons that are anecdotal.",
"title": "Contributions to mathematics and physics"
},
{
"paragraph_id": 57,
"text": "His collected works (Gesammelte Abhandlungen) have been published several times. The original versions of his papers contained \"many technical errors of varying degree\"; when the collection was first published, the errors were corrected and it was found that this could be done without major changes in the statements of the theorems, with one exception—a claimed proof of the continuum hypothesis. The errors were nonetheless so numerous and significant that it took Olga Taussky-Todd three years to make the corrections.",
"title": "Works"
}
] | David Hilbert was a German mathematician and one of the most influential mathematicians of the 19th and early 20th centuries. Hilbert discovered and developed a broad range of fundamental ideas including invariant theory, the calculus of variations, commutative algebra, algebraic number theory, the foundations of geometry, spectral theory of operators and its application to integral equations, mathematical physics, and the foundations of mathematics. Hilbert adopted and defended Georg Cantor's set theory and transfinite numbers. In 1900, he presented a collection of problems that set a course for mathematical research of the 20th century. Hilbert and his students contributed to establishing rigor and developed important tools used in modern mathematical physics. Hilbert was one of the founders of proof theory and mathematical logic. | 2001-11-12T18:04:33Z | 2023-12-30T20:01:14Z | [
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] | https://en.wikipedia.org/wiki/David_Hilbert |
8,303 | Down syndrome | Down syndrome or Down's syndrome, also known as trisomy 21, is a genetic disorder caused by the presence of all or part of a third copy of chromosome 21. It is usually associated with developmental delays, mild to moderate intellectual disability, and characteristic physical features. There are three types of Down syndrome, all with the same features: Trisomy 21, the most common type; Mosaic Down syndrome, and Translocation Down syndrome.
The parents of the affected individual are usually genetically normal. The probability increases from less than 0.1% in 20-year-old mothers to 3% in those of age 45. The extra chromosome is provided at conception as the egg and sperm combine. A very small percentage of 1-2% gets the additional chromosome in the embryo stage and it only impacts some of the cells in the body; this is known as Mosaic Down syndrome. Usually, babies get 23 chromosomes from each parent for a total of 46, whereas in Down syndrome, a third 21st chromosome is attached. It is believed to occur by chance, with no known behavioral activity or environmental factor that changes the probability. Down syndrome can be identified during pregnancy by prenatal screening, followed by diagnostic testing, or after birth by direct observation and genetic testing. Since the introduction of screening, Down syndrome pregnancies are often aborted (rates varying from 50 to 85% depending on maternal age, gestational age, and maternal race/ethnicity).
There is no cure for Down syndrome. Education and proper care have been shown to provide good quality of life. Some children with Down syndrome are educated in typical school classes, while others require more specialized education. Some individuals with Down syndrome graduate from high school, and a few attend post-secondary education. In adulthood, about 20% in the United States do paid work in some capacity, with many requiring a sheltered work environment. Support in financial and legal matters is often needed. Life expectancy is around 50 to 60 years in the developed world, with proper health care. Regular screening for health issues common in Down syndrome is recommended throughout the person's life.
Down syndrome is the most common chromosomal abnormality. It occurs in about 1 in 1,000 babies born each year. In the US this figure is given as one in 700 births. In 2015, Down syndrome was present in 5.4 million individuals globally and resulted in 27,000 deaths, down from 43,000 deaths in 1990. It is named after British doctor John Langdon Down, who fully described the syndrome in 1866. Some aspects of the condition were described earlier by French psychiatrist Jean-Étienne Dominique Esquirol in 1838 and French physician Édouard Séguin in 1844. The genetic cause of Down syndrome was discovered in 1959.
Those with Down syndrome nearly always have physical and intellectual disabilities. As adults, their mental abilities are typically similar to those of an 8- or 9-year-old. At the same time, their emotional and social awareness is very high. They can have poor immune function and generally reach developmental milestones at a later age. They have an increased risk of a number of health concerns, such as congenital heart defect, epilepsy, leukemia, and thyroid diseases.
People with Down syndrome may have these physical characteristics: a small chin, epicanthic folds, low muscle tone, a flat nasal bridge, a single crease of the palm, and a protruding tongue. A protruding tongue is caused by low tone and weak facial muscles, and often corrected with myofunctional exercises. Some characteristic airway features can lead to obstructive sleep apnea in around half of those with Down syndrome. Other common features include: excessive joint flexibility, extra space between big toe and second toe, single palm lines and short fingers.
Instability of the atlantoaxial joint occurs in about 1-2%. Atlantoaxial instability may cause myelopathy due to cervical spinal cord compression later in life, this often manifests as new onset weakness, problems with coordination, bowel or bladder incontinence, and gait dysfunction. Serial imaging cannot reliably predict future cervical cord compression, but changes can be seen on neurological exam. The condition is surgically corrected with spine surgery.
Growth in height is slower, resulting in adults who tend to have short stature—the average height for men is 154 cm (5 ft 1 in), and for women is 142 cm (4 ft 8 in). Individuals with Down syndrome are at increased risk for obesity as they age due to hypothyroidism, other medical issues and lifestyle. Growth charts have been developed specifically for children with Down syndrome.
This syndrome causes about a third of cases of intellectual disability. Many developmental milestones are delayed with the ability to crawl typically occurring around 8–22 months rather than 6–12 months, and the ability to walk independently typically occurring around 1–4 years rather than 9–18 months. Walking is acquired in 50% of children after 24 months.
Most individuals with Down syndrome have mild (IQ: 50–69) or moderate (IQ: 35–50) intellectual disability with some cases having severe (IQ: 20–35) difficulties. Those with mosaic Down syndrome typically have IQ scores 10–30 points higher than that. As they age, the gap tends to widen between people with Down syndrome and their same-age peers.
Commonly, individuals with Down syndrome have better language understanding than ability to speak. Babbling typically emerges around 15 months on average. 10-45% of those with Down syndrome have either a stutter or rapid and irregular speech, making it difficult to understand them. After reaching 30 years of age, some may lose their ability to speak.
They typically do fairly well with social skills. Behavior problems are not generally as great an issue as in other syndromes associated with intellectual disability. In children with Down syndrome, mental illness occurs in nearly 30% with autism occurring in 5–10%. People with Down syndrome experience a wide range of emotions. While people with Down syndrome are generally happy, symptoms of depression and anxiety may develop in early adulthood.
Children and adults with Down syndrome are at increased risk of epileptic seizures, which occur in 5–10% of children and up to 50% of adults. This includes an increased risk of a specific type of seizure called infantile spasms. Many (15%) who live 40 years or longer develop Alzheimer's disease. In those who reach 60 years of age, 50–70% have the disease.
Hearing and vision disorders occur in more than half of people with Down syndrome. Vision problems occur in 38-80% of cases. Between 20 and 50% have strabismus, in which the two eyes do not move together. Cataracts (cloudiness of the lens of the eye) occur in 15%, and may be present at birth. Keratoconus (a thin, cone-shaped cornea) and glaucoma (increased eye pressure) are also more common, as are refractive errors requiring glasses or contacts. Brushfield spots (small white or grayish/brown spots on the outer part of the iris) are present in 38 to 85% of individuals.
Hearing problems are found in 50–90% of children with Down syndrome. This is often the result of otitis media with effusion which occurs in 50–70% and chronic ear infections which occur in 40-60%. Ear infections often begin in the first year of life and are partly due to poor eustachian tube function. Excessive ear wax can also cause hearing loss due to obstruction of the outer ear canal. Even a mild degree of hearing loss can have negative consequences for speech, language understanding, and academics. It is important to rule out hearing loss as a factor in social and cognitive deterioration. Age-related hearing loss of the sensorineural type occurs at a much earlier age and affects 10–70% of people with Down syndrome.
The rate of congenital heart disease in newborns with Down syndrome is around 40%. Of those with heart disease, about 80% have an atrial septal defect or ventricular septal defect with the former being more common. Congenital heart disease can also put individuals at a higher risk of pulmonary hypertension, where arteries in the lungs narrow and cause inadequate blood oxygenation. Some of the genetic contributions to pulmonary hypertension in individuals with Down Syndrome are abnormal lung development, endothelial dysfunction, and proinflammatory genes. Mitral valve problems become common as people age, even in those without heart problems at birth. Other problems that may occur include tetralogy of Fallot and patent ductus arteriosus. People with Down syndrome have a lower risk of hardening of the arteries.
Although the overall risk of cancer in Down syndrome is not changed, the risk of testicular cancer and certain blood cancers, including acute lymphoblastic leukemia (ALL) and acute megakaryoblastic leukemia (AMKL) is increased while the risk of other non-blood cancers is decreased. People with Down syndrome are believed to have an increased risk of developing cancers derived from germ cells whether these cancers are blood- or non-blood-related.
Leukemia is 10 to 15 times more common in children with Down syndrome. In particular, acute lymphoblastic leukemia is 20 times more common and the megakaryoblastic form of acute myeloid leukemia (acute megakaryoblastic leukemia), is 500 times more common. Acute megakaryoblastic leukemia (AMKL) is a leukemia of megakaryoblasts, the precursors cells to megakaryocytes which form blood platelets. Acute lymphoblastic leukemia in Down syndrome accounts for 1–3% of all childhood cases of ALL. It occurs most often in those older than nine years or having a white blood cell count greater than 50,000 per microliter and is rare in those younger than one year old. ALL in Down syndrome tends to have poorer outcomes than other cases of ALL in people without Down syndrome.
In Down syndrome, AMKL is typically preceded by transient myeloproliferative disease (TMD), a disorder of blood cell production in which non-cancerous megakaryoblasts with a mutation in the GATA1 gene rapidly divide during the later period of pregnancy. The condition affects 3–10% of babies with Down. While it often spontaneously resolves within three months of birth, it can cause serious blood, liver, or other complications. In about 10% of cases, TMD progresses to AMKL during the three months to five years following its resolution.
People with Down syndrome have a lower risk of all major solid cancers, including those of lung, breast, and cervix, with the lowest relative rates occurring in those aged 50 years or older. This low risk is thought to be due to an increase in the expression of tumor suppressor genes present on chromosome 21. One exception is testicular germ cell cancer which occurs at a higher rate in Down syndrome.
Problems of the thyroid gland occur in 20–50% of individuals with Down syndrome. Low thyroid is the most common form, occurring in almost half of all individuals. Thyroid problems can be due to a poorly or nonfunctioning thyroid at birth (known as congenital hypothyroidism) which occurs in 1% or can develop later due to an attack on the thyroid by the immune system resulting in Graves' disease or autoimmune hypothyroidism. Type 1 diabetes mellitus is also more common.
Constipation occurs in nearly half of people with Down syndrome and may result in changes in behavior. One potential cause is Hirschsprung's disease, occurring in 2–15%, which is due to a lack of nerve cells controlling the colon. Other congenital problems can include duodenal atresia, imperforate anus and gastroesophageal reflux disease. Celiac disease affects about 7–20%
People with Down syndrome tend to be more susceptible to gingivitis as well as early, severe periodontal disease, necrotising ulcerative gingivitis, and early tooth loss, especially in the lower front teeth. While plaque and poor oral hygiene are contributing factors, the severity of these periodontal diseases cannot be explained solely by external factors. Research suggests that the severity is likely a result of a weakened immune system. The weakened immune system also contributes to increased incidence of yeast infections in the mouth (from Candida albicans).
People with Down syndrome also tend to have a more alkaline saliva resulting in a greater resistance to tooth decay, despite decreased quantities of saliva, less effective oral hygiene habits, and higher plaque indexes.
Higher rates of tooth wear and bruxism are also common. Other common oral manifestations of Down syndrome include enlarged hypotonic tongue, crusted and hypotonic lips, mouth breathing, narrow palate with crowded teeth, class III malocclusion with an underdeveloped maxilla and posterior crossbite, delayed exfoliation of baby teeth and delayed eruption of adult teeth, shorter roots on teeth, and often missing and malformed (usually smaller) teeth. Less common manifestations include cleft lip and palate and enamel hypocalcification (20% prevalence).
Taurodontism, an elongation of the pulp chamber, has a high prevalence in people with DS.
Males with Down syndrome usually do not father children, while females have lower rates of fertility relative to those who are unaffected. Fertility is estimated to be present in 30–50% of females. Menopause usually occurs at an earlier age. The poor fertility in males is thought to be due to problems with sperm development; however, it may also be related to not being sexually active. As of 2006, three instances of males with Down syndrome fathering children and 26 cases of females having children have been reported. Without assisted reproductive technologies, around half of the children of someone with Down syndrome will also have the syndrome.
The cause of the extra full or partial chromosome is still unknown. Most of the time, Down syndrome is caused by a random mistake in cell division during early development of the fetus, but not inherited, and there is no scientific research which shows that environmental factors or the parents' activities contribute to Down syndrome. The only factor that has been linked to the increased chance of having a baby with Down syndrome is advanced parental age. This is mostly associated with advanced maternal age but about 10 per cent of cases are associated with advanced paternal age.
Down syndrome is caused by having three copies of the genes on chromosome 21, rather than the usual two. The parents of the affected individual are typically genetically normal. Those who have one child with Down syndrome have about a 1% possibility of having a second child with the syndrome, if both parents are found to have normal karyotypes.
The extra chromosome content can arise through several different ways. The most common cause (about 92–95% of cases) is a complete extra copy of chromosome 21, resulting in trisomy 21. In 1-2.5% of cases, some of the cells in the body are normal and others have trisomy 21, known as mosaic Down syndrome. The other common mechanisms that can give rise to Down syndrome include: a Robertsonian translocation, isochromosome, or ring chromosome. These contain additional material from chromosome 21 and occur in about 2.5% of cases. An isochromosome results when the two long arms of a chromosome separate together rather than the long and short arm separating together during egg or sperm development.
Down syndrome (also known by the karyotype 47,XX,+21 for females and 47,XY,+21 for males) is mostly caused by a failure of the 21st chromosome to separate during egg or sperm development, known as nondisjunction. As a result, a sperm or egg cell is produced with an extra copy of chromosome 21; this cell thus has 24 chromosomes. When combined with a normal cell from the other parent, the baby has 47 chromosomes, with three copies of chromosome 21. About 88% of cases of trisomy 21 result from nonseparation of the chromosomes in the mother, 8% from nonseparation in the father, and 3% after the egg and sperm have merged.
Mosaic Down syndrome is diagnosed when there is a mixture of two types of cells: some cells have three copies of chromosome 21 but some cells have the typical two copies of chromosome 21. This type is the least common form of Down syndrome and accounts for only about 1% of all cases. Children with mosaic Down syndrome may have the same features as other children with Down syndrome. However, they may have fewer characteristics of the condition due to the presence of some (or many) cells with a typical number of chromosomes.
The extra chromosome 21 material may also occur due to a Robertsonian translocation in 2–4% of cases. In this translocation Down syndrome, the long arm of chromosome 21 is attached to another chromosome, often chromosome 14. In a male affected with Down syndrome, it results in a karyotype of 46XY,t(14q21q). This may be a new mutation or previously present in one of the parents. The parent with such a translocation is usually normal physically and mentally; however, during production of egg or sperm cells, a higher chance of creating reproductive cells with extra chromosome 21 material exists. This results in a 15% chance of having a child with Down syndrome when the mother is affected and a less than 5% probability if the father is affected. The probability of this type of Down syndrome is not related to the mother's age. Some children without Down syndrome may inherit the translocation and have a higher probability of having children of their own with Down syndrome. In this case it is sometimes known as familial Down syndrome.
The extra genetic material present in Down syndrome results in overexpression of a portion of the 310 genes located on chromosome 21. This overexpression has been estimated at 50%, due to the third copy of the chromosome present. Some research has suggested the Down syndrome critical region is located at bands 21q22.1–q22.3, with this area including genes for the amyloid precursor protein, superoxide dismutase, and likely the ETS2 proto oncogene. Other research, however, has not confirmed these findings. MicroRNAs are also proposed to be involved.
The dementia that occurs in Down syndrome is due to an excess of amyloid beta peptide produced in the brain and is similar to Alzheimer's disease, which also involves amyloid beta build-up. Amyloid beta is processed from amyloid precursor protein, the gene for which is located on chromosome 21. Senile plaques and neurofibrillary tangles are present in nearly all by 35 years of age, though dementia may not be present. It is hypothesized that those with Down syndrome lack a normal number of lymphocytes and produce less antibodies which is said to present an increased risk of infection.
Down syndrome is associated with an increased risk of some chronic diseases that are typically associated with older age such as Alzheimer's disease. It is believed that accelerated aging occurs and increases the biological age of tissues, but molecular evidence for this hypothesis is sparse. According to a biomarker of tissue age known as epigenetic clock, it is hypothesized that trisomy 21 increases the age of blood and brain tissue (on average by 6.6 years).
Guidelines recommend screening for Down syndrome to be offered to all pregnant women, regardless of age. A number of tests are used, with varying levels of accuracy. They are typically used in combination to increase the detection rate. None can be definitive, thus if screening is positive, either amniocentesis or chorionic villus sampling is required to confirm the diagnosis.
When screening tests predict a high possibility of Down syndrome, a more invasive diagnostic test (amniocentesis or chorionic villus sampling) is needed to confirm the diagnosis.
Prenatal ultrasound can be used to screen for Down syndrome. Findings that indicate increased chances when seen at 14 to 24 weeks of gestation include a small or no nasal bone, large ventricles, nuchal fold thickness, and an abnormal right subclavian artery, among others. The presence or absence of many markers is more accurate. Increased fetal nuchal translucency (NT) indicates an increased possibility of Down syndrome picking up 75–80% of cases and being falsely positive in 6%.
Several blood markers can be measured to predict the chances of Down syndrome during the first or second trimester. Testing in both trimesters is sometimes recommended and test results are often combined with ultrasound results. In the second trimester, often two or three tests are used in combination with two or three of: α-fetoprotein, unconjugated estriol, total hCG, and free βhCG detecting about 60–70% of cases.
Testing of the mother's blood for fetal DNA is being studied and appears promising in the first trimester. The International Society for Prenatal Diagnosis considers it a reasonable screening option for those women whose pregnancies are at a high likelihood of trisomy 21. Accuracy has been reported at 98.6% in the first trimester of pregnancy. Confirmatory testing by invasive techniques (amniocentesis, CVS) is still required to confirm the screening result.
For combinations of ultrasonography and non-genetic blood tests, screening in both the first and second trimesters is better than just screening in the first trimester. The different screening techniques in use are able to pick up 90–95% of cases, with a false-positive rate of 2–5%. If Down syndrome occurs in one in 500 pregnancies with a 90% detection rate and the test used has a 5% false-positive rate, this means, of 20 women who test positive on screening, only one will not have a fetus with Down syndrome confirmed. If the screening test has a 2% false-positive rate, this means, of 50 women who test positive on screening, one will not have a fetus with Down syndrome.
Amniocentesis and chorionic villus sampling are more reliable tests, but they increase the risk of miscarriage by between 0.5-1%. The risk of limb problems may be increased in the offspring if chorionic villus sampling is performed before 10 weeks.
The risk from the procedure is greater the earlier it is performed, thus amniocentesis is not recommended before 15 weeks gestational age and chorionic villus sampling before 10 weeks gestational age.
About 92% of pregnancies in Europe with a diagnosis of Down syndrome are terminated. As a result, there is almost no one with Down syndrome in Iceland and Denmark, where screening is commonplace. In the United States, the termination rate after diagnosis is around 75%, but varies from 61 to 93%, depending on the population surveyed. Rates are lower among women who are younger and have decreased over time. When asked if they would have a termination if their fetus tested positive, 23–33% said yes, when high-risk pregnant women were asked, 46–86% said yes, and when women who screened positive are asked, 89–97% say yes.
The diagnosis can often be suspected based on the child's physical appearance at birth. Informing the parents of a diagnosis needs to be made as soon as possible, with care and sensitivity. Even an uncertain diagnosis needs to be informed of in the same way. This allows for a longer time for processing the information.
An analysis of the child's chromosomes is needed to confirm the diagnosis, and to determine if a translocation is present, as this may help determine the chances of the child's parents having further children with Down syndrome.
Efforts such as early childhood intervention, therapies, screening for common medical issues, a good family environment, and work-related training can improve the development of children with Down syndrome and provide good quality of life. Common therapies utilized include physical therapy, occupational therapy and speech therapy. Education and proper care can provide a positive quality of life. Typical childhood vaccinations are recommended.
A number of health organizations have issued recommendations for screening those with Down syndrome for particular diseases. This is recommended to be done systematically.
At birth, all children should get an electrocardiogram and ultrasound of the heart. Surgical repair of heart problems may be required as early as three months of age. Heart valve problems may occur in young adults, and further ultrasound evaluation may be needed in adolescents and in early adulthood. Due to the elevated risk of testicular cancer, some recommend checking the person's testicles yearly.
Some people with Down syndrome experience hearing loss. In this instance, hearing aids or other amplification devices can be useful for language learning. Speech therapy may be useful and is recommended to be started around nine months of age. As those with Down syndrome typically have good hand-eye coordination, learning sign language is a helpful communication tool. Augmentative and alternative communication methods, such as pointing, body language, objects, or pictures, are often used to help with communication. Behavioral issues and mental illness are typically managed with counseling or medications.
Education programs before reaching school age may be useful. School-age children with Down syndrome may benefit from inclusive education (whereby students of differing abilities are placed in classes with their peers of the same age), provided some adjustments are made to the curriculum. In the United States, the Individuals with Disabilities Education Act of 1975 requires public schools generally to allow attendance by students with Down syndrome.
Individuals with Down syndrome may learn better visually. Drawing may help with language, speech, and reading skills. Children with Down syndrome still often have difficulty with sentence structure and grammar, as well as developing the ability to speak clearly. Several types of early intervention can help with cognitive development. Efforts to develop motor skills include physical therapy, speech and language therapy, and occupational therapy. Physical therapy focuses specifically on motor development and teaching children to interact with their environment. Speech and language therapy can help prepare for later language. Lastly, occupational therapy can help with skills needed for later independence.
Tympanostomy tubes are often needed and often more than one set during the person's childhood. Tonsillectomy is also often done to help with sleep apnea and throat infections. Surgery does not correct every instance of sleep apnea and a continuous positive airway pressure (CPAP) machine may be useful in those cases.
Efforts to prevent respiratory syncytial virus (RSV) infection with human monoclonal antibodies should be considered, especially in those with heart problems. In those who develop dementia there is no evidence for memantine, donepezil, rivastigmine, or galantamine.
Between 5-15% of children with Down syndrome in Sweden attend regular school. Some graduate from high school; however, most do not. Of those with intellectual disability in the United States who attended high school about 40% graduated. Many learn to read and write and some are able to do paid work. In adulthood about 20% in the United States do paid work in some capacity. In Sweden, however, less than 1% have regular jobs. Many are able to live semi-independently, but they often require help with financial, medical, and legal matters. Those with mosaic Down syndrome usually have better outcomes.
Individuals with Down syndrome have a higher risk of early death than the general population. This is most often from heart problems or infections. Following improved medical care, particularly for heart and gastrointestinal problems, the life expectancy has increased. This increase has been from 12 years in 1912, to 25 years in the 1980s, to 50 to 60 years in the developed world in the 2000s. Data collected between the 1985–2003 showed between 4-12% infants with Down syndrome die in the first year of life. The probability of long-term survival is partly determined by the presence of heart problems. From research at the turn of the century, it tracked those with congenital heart problems, showing 60% survived to at least 10 years and 50% survived to at least 30 years of age. The research failed to track further aging beyond 30 years. In those without heart problems, 85% studied survived to at least 10 years and 80% survived to at least 30 years of age. It is estimated that 10% lived to 70 years of age in the early 2000s. Much of this data is outdated and life expectancy has drastically improved with more equitable healthcare and continuous advancement of surgical practice. The National Down Syndrome Society provides information regarding raising a child with Down syndrome.
Down syndrome is the most common chromosomal abnormality in humans. Globally, as of 2010, Down syndrome occurs in about 1 per 1,000 births and results in about 17,000 deaths. More children are born with Down syndrome in countries where abortion is not allowed and in countries where pregnancy more commonly occurs at a later age. About 1.4 per 1,000 live births in the United States and 1.1 per 1,000 live births in Norway are affected. In the 1950s, in the United States, it occurred in 2 per 1,000 live births with the decrease since then due to prenatal screening and abortions. The number of pregnancies with Down syndrome is more than two times greater with many spontaneously aborting. It is the cause of 8% of all congenital disorders.
Maternal age affects the chances of having a pregnancy with Down syndrome. At age 20, the chance is 1 in 1,441; at age 30, it is 1 in 959; at age 40, it is 1 in 84; and at age 50 it is 1 in 44. Although the probability increases with maternal age, 70% of children with Down syndrome are born to women 35 years of age and younger, because younger people have more children. The father's older age is also a risk factor in women older than 35, but not in women younger than 35, and may partly explain the increase in risk as women age.
English physician John Langdon Down first described Down syndrome in 1862, recognizing it as a distinct type of mental disability, and again in a more widely published report in 1866. Édouard Séguin described it as separate from cretinism in 1844. By the 20th century, Down syndrome had become the most recognizable form of mental disability.
Due to his perception that children with Down syndrome shared facial similarities with those of Blumenbach's Mongolian race, John Langdon Down used the term "mongoloid". He felt that the existence of Down syndrome confirmed that all peoples were genetically related. In the 1950s with discovery of the underlying cause as being related to chromosomes, concerns about the race-based nature of the name increased.
In 1961, a group of nineteen scientists suggested that "mongolism" had "misleading connotations" and had become "an embarrassing term". The World Health Organization (WHO) dropped the term in 1965 after a request by the delegation from the Mongolian People's Republic. While this racist terminology continued to be used until the late twentieth century, it is now considered unacceptable and is no longer in common use.
In antiquity, many infants with disabilities were either killed or abandoned. In June 2020, the earliest incidence of Down syndrome was found in genomic evidence from an infant that was buried before 3200 BC at Poulnabrone dolmen in Ireland. Researchers believe that a number of historical pieces of art portray Down syndrome, including pottery from the pre-Columbian Tumaco-La Tolita culture in present-day Colombia and Ecuador, and the 16th-century painting The Adoration of the Christ Child.
In the 20th century, many individuals with Down syndrome were institutionalized, few of the associated medical problems were treated, and most people died in infancy or early adulthood. With the rise of the eugenics movement, 33 of the then 48 U.S. states and several countries began programs of forced sterilization of individuals with Down syndrome and comparable degrees of disability. Action T4 in Nazi Germany saw the systematic murder of people with Down syndrome made public policy.
With the discovery of karyotype techniques in the 1950s it became possible to identify abnormalities of chromosomal number or shape. In 1959 Jérôme Lejeune reported the discovery that Down syndrome resulted from an extra chromosome. However, Lejeune's claim to the discovery has been disputed, and in 2014 the Scientific Council of the French Federation of Human Genetics unanimously awarded its Grand Prize to his colleague Marthe Gautier for her role in this discovery. The discovery took place in the laboratory of Raymond Turpin at the Hôpital Trousseau in Paris, France. Jérôme Lejeune and Marthe Gautier were both his students.
As a result of this discovery, the condition became known as trisomy 21. Even before the discovery of its cause, the presence of the syndrome in all races, its association with older maternal age, and its rarity of recurrence had been noticed. Medical texts had assumed it was caused by a combination of inheritable factors that had not been identified. Other theories had focused on injuries sustained during birth.
Down syndrome is named after John Langdon Down. He was the first person to provide an accurate description of the syndrome. His research that was published in 1866 earned him the recognition as the Father of the syndrome. While others had previously recognized components of the condition, John Langdon Down described the syndrome as a distinct, unique medical condition.
In 1975, the United States National Institutes of Health (NIH) convened a conference to standardize the naming and recommended replacing the possessive form, "Down's syndrome" with "Down syndrome". However, both the possessive and nonpossessive forms remain in use by the general population. The term "trisomy 21" is also commonly used.
Most obstetricians argue that not offering screening for Down syndrome is unethical. As it is a medically reasonable procedure, per informed consent, people should at least be given information about it. It will then be the woman's choice, based on her personal beliefs, how much or how little screening she wishes. When results from testing become available, it is also considered unethical not to give the results to the person in question.
Some bioethicists deem it reasonable for parents to select a child who would have the highest well-being. One criticism of this reasoning is that it often values those with disabilities less. Some parents argue that Down syndrome should not be prevented or cured and that eliminating Down syndrome amounts to genocide. The disability rights movement does not have a position on screening, although some members consider testing and abortion discriminatory. Some in the United States who are anti-abortion support abortion if the fetus is disabled, while others do not. Of a group of 40 mothers in the United States who have had one child with Down syndrome, half agreed to screening in the next pregnancy.
Within the US, some Protestant denominations see abortion as acceptable when a fetus has Down syndrome while Orthodox Christianity and Roman Catholicism do not. Some of those against screening refer to it as a form of eugenics. Disagreement exists within Islam regarding the acceptability of abortion in those carrying a fetus with Down syndrome. Some Islamic countries allow abortion, while others do not. Parents may be stigmatized whichever decision they make.
Advocacy groups for individuals with Down syndrome began to be formed after the Second World War. These were organizations advocating for the inclusion of people with Down syndrome into the general school system and for a greater understanding of the condition among the general population, as well as groups providing support for families with children living with Down syndrome. Before this individuals with Down syndrome were often placed in mental hospitals or asylums. Organizations included the Royal Society for Handicapped Children and Adults founded in the UK in 1946 by Judy Fryd, Kobato Kai founded in Japan in 1964, the National Down Syndrome Congress founded in the United States in 1973 by Kathryn McGee and others, and the National Down Syndrome Society founded in 1979 in the United States. The first Roman Catholic order of nuns for women with Down Syndrome, Little Sisters Disciples of the Lamb, was founded in 1985 in France.
The first World Down Syndrome Day was held on 21 March 2006. The day and month were chosen to correspond with 21 and trisomy, respectively. It was recognized by the United Nations General Assembly in 2011.
Efforts are underway to determine how the extra chromosome 21 material causes Down syndrome, as currently this is unknown, and to develop treatments to improve intelligence in those with the syndrome. Two efforts being studied are the use stem cells and gene therapy. Other methods being studied include the use of antioxidants, gamma secretase inhibition, adrenergic agonists, and memantine. Research is often carried out on an animal model, the Ts65Dn mouse.
Down syndrome may also occur in hominids other than humans. In great apes chromosome 22 corresponds to the human chromosome 21 and thus trisomy 22 causes Down syndrome in apes. The condition was observed in a common chimpanzee in 1969 and a Bornean orangutan in 1979, but neither lived very long. The common chimpanzee Kanako (born around 1993, in Japan) has become the longest-lived known example of this condition. Kanako has some of the same symptoms that are common in human Down syndrome. It is unknown how common this condition is in chimps, but it is plausible it could be roughly as common as Down syndrome is in humans.
Individuals
Television and film | [
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"text": "The parents of the affected individual are usually genetically normal. The probability increases from less than 0.1% in 20-year-old mothers to 3% in those of age 45. The extra chromosome is provided at conception as the egg and sperm combine. A very small percentage of 1-2% gets the additional chromosome in the embryo stage and it only impacts some of the cells in the body; this is known as Mosaic Down syndrome. Usually, babies get 23 chromosomes from each parent for a total of 46, whereas in Down syndrome, a third 21st chromosome is attached. It is believed to occur by chance, with no known behavioral activity or environmental factor that changes the probability. Down syndrome can be identified during pregnancy by prenatal screening, followed by diagnostic testing, or after birth by direct observation and genetic testing. Since the introduction of screening, Down syndrome pregnancies are often aborted (rates varying from 50 to 85% depending on maternal age, gestational age, and maternal race/ethnicity).",
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{
"paragraph_id": 2,
"text": "There is no cure for Down syndrome. Education and proper care have been shown to provide good quality of life. Some children with Down syndrome are educated in typical school classes, while others require more specialized education. Some individuals with Down syndrome graduate from high school, and a few attend post-secondary education. In adulthood, about 20% in the United States do paid work in some capacity, with many requiring a sheltered work environment. Support in financial and legal matters is often needed. Life expectancy is around 50 to 60 years in the developed world, with proper health care. Regular screening for health issues common in Down syndrome is recommended throughout the person's life.",
"title": ""
},
{
"paragraph_id": 3,
"text": "Down syndrome is the most common chromosomal abnormality. It occurs in about 1 in 1,000 babies born each year. In the US this figure is given as one in 700 births. In 2015, Down syndrome was present in 5.4 million individuals globally and resulted in 27,000 deaths, down from 43,000 deaths in 1990. It is named after British doctor John Langdon Down, who fully described the syndrome in 1866. Some aspects of the condition were described earlier by French psychiatrist Jean-Étienne Dominique Esquirol in 1838 and French physician Édouard Séguin in 1844. The genetic cause of Down syndrome was discovered in 1959.",
"title": ""
},
{
"paragraph_id": 4,
"text": "Those with Down syndrome nearly always have physical and intellectual disabilities. As adults, their mental abilities are typically similar to those of an 8- or 9-year-old. At the same time, their emotional and social awareness is very high. They can have poor immune function and generally reach developmental milestones at a later age. They have an increased risk of a number of health concerns, such as congenital heart defect, epilepsy, leukemia, and thyroid diseases.",
"title": "Signs and symptoms"
},
{
"paragraph_id": 5,
"text": "People with Down syndrome may have these physical characteristics: a small chin, epicanthic folds, low muscle tone, a flat nasal bridge, a single crease of the palm, and a protruding tongue. A protruding tongue is caused by low tone and weak facial muscles, and often corrected with myofunctional exercises. Some characteristic airway features can lead to obstructive sleep apnea in around half of those with Down syndrome. Other common features include: excessive joint flexibility, extra space between big toe and second toe, single palm lines and short fingers.",
"title": "Signs and symptoms"
},
{
"paragraph_id": 6,
"text": "Instability of the atlantoaxial joint occurs in about 1-2%. Atlantoaxial instability may cause myelopathy due to cervical spinal cord compression later in life, this often manifests as new onset weakness, problems with coordination, bowel or bladder incontinence, and gait dysfunction. Serial imaging cannot reliably predict future cervical cord compression, but changes can be seen on neurological exam. The condition is surgically corrected with spine surgery.",
"title": "Signs and symptoms"
},
{
"paragraph_id": 7,
"text": "Growth in height is slower, resulting in adults who tend to have short stature—the average height for men is 154 cm (5 ft 1 in), and for women is 142 cm (4 ft 8 in). Individuals with Down syndrome are at increased risk for obesity as they age due to hypothyroidism, other medical issues and lifestyle. Growth charts have been developed specifically for children with Down syndrome.",
"title": "Signs and symptoms"
},
{
"paragraph_id": 8,
"text": "This syndrome causes about a third of cases of intellectual disability. Many developmental milestones are delayed with the ability to crawl typically occurring around 8–22 months rather than 6–12 months, and the ability to walk independently typically occurring around 1–4 years rather than 9–18 months. Walking is acquired in 50% of children after 24 months.",
"title": "Signs and symptoms"
},
{
"paragraph_id": 9,
"text": "Most individuals with Down syndrome have mild (IQ: 50–69) or moderate (IQ: 35–50) intellectual disability with some cases having severe (IQ: 20–35) difficulties. Those with mosaic Down syndrome typically have IQ scores 10–30 points higher than that. As they age, the gap tends to widen between people with Down syndrome and their same-age peers.",
"title": "Signs and symptoms"
},
{
"paragraph_id": 10,
"text": "Commonly, individuals with Down syndrome have better language understanding than ability to speak. Babbling typically emerges around 15 months on average. 10-45% of those with Down syndrome have either a stutter or rapid and irregular speech, making it difficult to understand them. After reaching 30 years of age, some may lose their ability to speak.",
"title": "Signs and symptoms"
},
{
"paragraph_id": 11,
"text": "They typically do fairly well with social skills. Behavior problems are not generally as great an issue as in other syndromes associated with intellectual disability. In children with Down syndrome, mental illness occurs in nearly 30% with autism occurring in 5–10%. People with Down syndrome experience a wide range of emotions. While people with Down syndrome are generally happy, symptoms of depression and anxiety may develop in early adulthood.",
"title": "Signs and symptoms"
},
{
"paragraph_id": 12,
"text": "Children and adults with Down syndrome are at increased risk of epileptic seizures, which occur in 5–10% of children and up to 50% of adults. This includes an increased risk of a specific type of seizure called infantile spasms. Many (15%) who live 40 years or longer develop Alzheimer's disease. In those who reach 60 years of age, 50–70% have the disease.",
"title": "Signs and symptoms"
},
{
"paragraph_id": 13,
"text": "Hearing and vision disorders occur in more than half of people with Down syndrome. Vision problems occur in 38-80% of cases. Between 20 and 50% have strabismus, in which the two eyes do not move together. Cataracts (cloudiness of the lens of the eye) occur in 15%, and may be present at birth. Keratoconus (a thin, cone-shaped cornea) and glaucoma (increased eye pressure) are also more common, as are refractive errors requiring glasses or contacts. Brushfield spots (small white or grayish/brown spots on the outer part of the iris) are present in 38 to 85% of individuals.",
"title": "Signs and symptoms"
},
{
"paragraph_id": 14,
"text": "Hearing problems are found in 50–90% of children with Down syndrome. This is often the result of otitis media with effusion which occurs in 50–70% and chronic ear infections which occur in 40-60%. Ear infections often begin in the first year of life and are partly due to poor eustachian tube function. Excessive ear wax can also cause hearing loss due to obstruction of the outer ear canal. Even a mild degree of hearing loss can have negative consequences for speech, language understanding, and academics. It is important to rule out hearing loss as a factor in social and cognitive deterioration. Age-related hearing loss of the sensorineural type occurs at a much earlier age and affects 10–70% of people with Down syndrome.",
"title": "Signs and symptoms"
},
{
"paragraph_id": 15,
"text": "The rate of congenital heart disease in newborns with Down syndrome is around 40%. Of those with heart disease, about 80% have an atrial septal defect or ventricular septal defect with the former being more common. Congenital heart disease can also put individuals at a higher risk of pulmonary hypertension, where arteries in the lungs narrow and cause inadequate blood oxygenation. Some of the genetic contributions to pulmonary hypertension in individuals with Down Syndrome are abnormal lung development, endothelial dysfunction, and proinflammatory genes. Mitral valve problems become common as people age, even in those without heart problems at birth. Other problems that may occur include tetralogy of Fallot and patent ductus arteriosus. People with Down syndrome have a lower risk of hardening of the arteries.",
"title": "Signs and symptoms"
},
{
"paragraph_id": 16,
"text": "Although the overall risk of cancer in Down syndrome is not changed, the risk of testicular cancer and certain blood cancers, including acute lymphoblastic leukemia (ALL) and acute megakaryoblastic leukemia (AMKL) is increased while the risk of other non-blood cancers is decreased. People with Down syndrome are believed to have an increased risk of developing cancers derived from germ cells whether these cancers are blood- or non-blood-related.",
"title": "Signs and symptoms"
},
{
"paragraph_id": 17,
"text": "Leukemia is 10 to 15 times more common in children with Down syndrome. In particular, acute lymphoblastic leukemia is 20 times more common and the megakaryoblastic form of acute myeloid leukemia (acute megakaryoblastic leukemia), is 500 times more common. Acute megakaryoblastic leukemia (AMKL) is a leukemia of megakaryoblasts, the precursors cells to megakaryocytes which form blood platelets. Acute lymphoblastic leukemia in Down syndrome accounts for 1–3% of all childhood cases of ALL. It occurs most often in those older than nine years or having a white blood cell count greater than 50,000 per microliter and is rare in those younger than one year old. ALL in Down syndrome tends to have poorer outcomes than other cases of ALL in people without Down syndrome.",
"title": "Signs and symptoms"
},
{
"paragraph_id": 18,
"text": "In Down syndrome, AMKL is typically preceded by transient myeloproliferative disease (TMD), a disorder of blood cell production in which non-cancerous megakaryoblasts with a mutation in the GATA1 gene rapidly divide during the later period of pregnancy. The condition affects 3–10% of babies with Down. While it often spontaneously resolves within three months of birth, it can cause serious blood, liver, or other complications. In about 10% of cases, TMD progresses to AMKL during the three months to five years following its resolution.",
"title": "Signs and symptoms"
},
{
"paragraph_id": 19,
"text": "People with Down syndrome have a lower risk of all major solid cancers, including those of lung, breast, and cervix, with the lowest relative rates occurring in those aged 50 years or older. This low risk is thought to be due to an increase in the expression of tumor suppressor genes present on chromosome 21. One exception is testicular germ cell cancer which occurs at a higher rate in Down syndrome.",
"title": "Signs and symptoms"
},
{
"paragraph_id": 20,
"text": "Problems of the thyroid gland occur in 20–50% of individuals with Down syndrome. Low thyroid is the most common form, occurring in almost half of all individuals. Thyroid problems can be due to a poorly or nonfunctioning thyroid at birth (known as congenital hypothyroidism) which occurs in 1% or can develop later due to an attack on the thyroid by the immune system resulting in Graves' disease or autoimmune hypothyroidism. Type 1 diabetes mellitus is also more common.",
"title": "Signs and symptoms"
},
{
"paragraph_id": 21,
"text": "Constipation occurs in nearly half of people with Down syndrome and may result in changes in behavior. One potential cause is Hirschsprung's disease, occurring in 2–15%, which is due to a lack of nerve cells controlling the colon. Other congenital problems can include duodenal atresia, imperforate anus and gastroesophageal reflux disease. Celiac disease affects about 7–20%",
"title": "Signs and symptoms"
},
{
"paragraph_id": 22,
"text": "People with Down syndrome tend to be more susceptible to gingivitis as well as early, severe periodontal disease, necrotising ulcerative gingivitis, and early tooth loss, especially in the lower front teeth. While plaque and poor oral hygiene are contributing factors, the severity of these periodontal diseases cannot be explained solely by external factors. Research suggests that the severity is likely a result of a weakened immune system. The weakened immune system also contributes to increased incidence of yeast infections in the mouth (from Candida albicans).",
"title": "Signs and symptoms"
},
{
"paragraph_id": 23,
"text": "People with Down syndrome also tend to have a more alkaline saliva resulting in a greater resistance to tooth decay, despite decreased quantities of saliva, less effective oral hygiene habits, and higher plaque indexes.",
"title": "Signs and symptoms"
},
{
"paragraph_id": 24,
"text": "Higher rates of tooth wear and bruxism are also common. Other common oral manifestations of Down syndrome include enlarged hypotonic tongue, crusted and hypotonic lips, mouth breathing, narrow palate with crowded teeth, class III malocclusion with an underdeveloped maxilla and posterior crossbite, delayed exfoliation of baby teeth and delayed eruption of adult teeth, shorter roots on teeth, and often missing and malformed (usually smaller) teeth. Less common manifestations include cleft lip and palate and enamel hypocalcification (20% prevalence).",
"title": "Signs and symptoms"
},
{
"paragraph_id": 25,
"text": "Taurodontism, an elongation of the pulp chamber, has a high prevalence in people with DS.",
"title": "Signs and symptoms"
},
{
"paragraph_id": 26,
"text": "Males with Down syndrome usually do not father children, while females have lower rates of fertility relative to those who are unaffected. Fertility is estimated to be present in 30–50% of females. Menopause usually occurs at an earlier age. The poor fertility in males is thought to be due to problems with sperm development; however, it may also be related to not being sexually active. As of 2006, three instances of males with Down syndrome fathering children and 26 cases of females having children have been reported. Without assisted reproductive technologies, around half of the children of someone with Down syndrome will also have the syndrome.",
"title": "Signs and symptoms"
},
{
"paragraph_id": 27,
"text": "The cause of the extra full or partial chromosome is still unknown. Most of the time, Down syndrome is caused by a random mistake in cell division during early development of the fetus, but not inherited, and there is no scientific research which shows that environmental factors or the parents' activities contribute to Down syndrome. The only factor that has been linked to the increased chance of having a baby with Down syndrome is advanced parental age. This is mostly associated with advanced maternal age but about 10 per cent of cases are associated with advanced paternal age.",
"title": "Cause"
},
{
"paragraph_id": 28,
"text": "Down syndrome is caused by having three copies of the genes on chromosome 21, rather than the usual two. The parents of the affected individual are typically genetically normal. Those who have one child with Down syndrome have about a 1% possibility of having a second child with the syndrome, if both parents are found to have normal karyotypes.",
"title": "Cause"
},
{
"paragraph_id": 29,
"text": "The extra chromosome content can arise through several different ways. The most common cause (about 92–95% of cases) is a complete extra copy of chromosome 21, resulting in trisomy 21. In 1-2.5% of cases, some of the cells in the body are normal and others have trisomy 21, known as mosaic Down syndrome. The other common mechanisms that can give rise to Down syndrome include: a Robertsonian translocation, isochromosome, or ring chromosome. These contain additional material from chromosome 21 and occur in about 2.5% of cases. An isochromosome results when the two long arms of a chromosome separate together rather than the long and short arm separating together during egg or sperm development.",
"title": "Cause"
},
{
"paragraph_id": 30,
"text": "Down syndrome (also known by the karyotype 47,XX,+21 for females and 47,XY,+21 for males) is mostly caused by a failure of the 21st chromosome to separate during egg or sperm development, known as nondisjunction. As a result, a sperm or egg cell is produced with an extra copy of chromosome 21; this cell thus has 24 chromosomes. When combined with a normal cell from the other parent, the baby has 47 chromosomes, with three copies of chromosome 21. About 88% of cases of trisomy 21 result from nonseparation of the chromosomes in the mother, 8% from nonseparation in the father, and 3% after the egg and sperm have merged.",
"title": "Cause"
},
{
"paragraph_id": 31,
"text": "Mosaic Down syndrome is diagnosed when there is a mixture of two types of cells: some cells have three copies of chromosome 21 but some cells have the typical two copies of chromosome 21. This type is the least common form of Down syndrome and accounts for only about 1% of all cases. Children with mosaic Down syndrome may have the same features as other children with Down syndrome. However, they may have fewer characteristics of the condition due to the presence of some (or many) cells with a typical number of chromosomes.",
"title": "Cause"
},
{
"paragraph_id": 32,
"text": "The extra chromosome 21 material may also occur due to a Robertsonian translocation in 2–4% of cases. In this translocation Down syndrome, the long arm of chromosome 21 is attached to another chromosome, often chromosome 14. In a male affected with Down syndrome, it results in a karyotype of 46XY,t(14q21q). This may be a new mutation or previously present in one of the parents. The parent with such a translocation is usually normal physically and mentally; however, during production of egg or sperm cells, a higher chance of creating reproductive cells with extra chromosome 21 material exists. This results in a 15% chance of having a child with Down syndrome when the mother is affected and a less than 5% probability if the father is affected. The probability of this type of Down syndrome is not related to the mother's age. Some children without Down syndrome may inherit the translocation and have a higher probability of having children of their own with Down syndrome. In this case it is sometimes known as familial Down syndrome.",
"title": "Cause"
},
{
"paragraph_id": 33,
"text": "The extra genetic material present in Down syndrome results in overexpression of a portion of the 310 genes located on chromosome 21. This overexpression has been estimated at 50%, due to the third copy of the chromosome present. Some research has suggested the Down syndrome critical region is located at bands 21q22.1–q22.3, with this area including genes for the amyloid precursor protein, superoxide dismutase, and likely the ETS2 proto oncogene. Other research, however, has not confirmed these findings. MicroRNAs are also proposed to be involved.",
"title": "Mechanism"
},
{
"paragraph_id": 34,
"text": "The dementia that occurs in Down syndrome is due to an excess of amyloid beta peptide produced in the brain and is similar to Alzheimer's disease, which also involves amyloid beta build-up. Amyloid beta is processed from amyloid precursor protein, the gene for which is located on chromosome 21. Senile plaques and neurofibrillary tangles are present in nearly all by 35 years of age, though dementia may not be present. It is hypothesized that those with Down syndrome lack a normal number of lymphocytes and produce less antibodies which is said to present an increased risk of infection.",
"title": "Mechanism"
},
{
"paragraph_id": 35,
"text": "Down syndrome is associated with an increased risk of some chronic diseases that are typically associated with older age such as Alzheimer's disease. It is believed that accelerated aging occurs and increases the biological age of tissues, but molecular evidence for this hypothesis is sparse. According to a biomarker of tissue age known as epigenetic clock, it is hypothesized that trisomy 21 increases the age of blood and brain tissue (on average by 6.6 years).",
"title": "Mechanism"
},
{
"paragraph_id": 36,
"text": "Guidelines recommend screening for Down syndrome to be offered to all pregnant women, regardless of age. A number of tests are used, with varying levels of accuracy. They are typically used in combination to increase the detection rate. None can be definitive, thus if screening is positive, either amniocentesis or chorionic villus sampling is required to confirm the diagnosis.",
"title": "Diagnosis"
},
{
"paragraph_id": 37,
"text": "When screening tests predict a high possibility of Down syndrome, a more invasive diagnostic test (amniocentesis or chorionic villus sampling) is needed to confirm the diagnosis.",
"title": "Diagnosis"
},
{
"paragraph_id": 38,
"text": "Prenatal ultrasound can be used to screen for Down syndrome. Findings that indicate increased chances when seen at 14 to 24 weeks of gestation include a small or no nasal bone, large ventricles, nuchal fold thickness, and an abnormal right subclavian artery, among others. The presence or absence of many markers is more accurate. Increased fetal nuchal translucency (NT) indicates an increased possibility of Down syndrome picking up 75–80% of cases and being falsely positive in 6%.",
"title": "Diagnosis"
},
{
"paragraph_id": 39,
"text": "Several blood markers can be measured to predict the chances of Down syndrome during the first or second trimester. Testing in both trimesters is sometimes recommended and test results are often combined with ultrasound results. In the second trimester, often two or three tests are used in combination with two or three of: α-fetoprotein, unconjugated estriol, total hCG, and free βhCG detecting about 60–70% of cases.",
"title": "Diagnosis"
},
{
"paragraph_id": 40,
"text": "Testing of the mother's blood for fetal DNA is being studied and appears promising in the first trimester. The International Society for Prenatal Diagnosis considers it a reasonable screening option for those women whose pregnancies are at a high likelihood of trisomy 21. Accuracy has been reported at 98.6% in the first trimester of pregnancy. Confirmatory testing by invasive techniques (amniocentesis, CVS) is still required to confirm the screening result.",
"title": "Diagnosis"
},
{
"paragraph_id": 41,
"text": "For combinations of ultrasonography and non-genetic blood tests, screening in both the first and second trimesters is better than just screening in the first trimester. The different screening techniques in use are able to pick up 90–95% of cases, with a false-positive rate of 2–5%. If Down syndrome occurs in one in 500 pregnancies with a 90% detection rate and the test used has a 5% false-positive rate, this means, of 20 women who test positive on screening, only one will not have a fetus with Down syndrome confirmed. If the screening test has a 2% false-positive rate, this means, of 50 women who test positive on screening, one will not have a fetus with Down syndrome.",
"title": "Diagnosis"
},
{
"paragraph_id": 42,
"text": "Amniocentesis and chorionic villus sampling are more reliable tests, but they increase the risk of miscarriage by between 0.5-1%. The risk of limb problems may be increased in the offspring if chorionic villus sampling is performed before 10 weeks.",
"title": "Diagnosis"
},
{
"paragraph_id": 43,
"text": "The risk from the procedure is greater the earlier it is performed, thus amniocentesis is not recommended before 15 weeks gestational age and chorionic villus sampling before 10 weeks gestational age.",
"title": "Diagnosis"
},
{
"paragraph_id": 44,
"text": "About 92% of pregnancies in Europe with a diagnosis of Down syndrome are terminated. As a result, there is almost no one with Down syndrome in Iceland and Denmark, where screening is commonplace. In the United States, the termination rate after diagnosis is around 75%, but varies from 61 to 93%, depending on the population surveyed. Rates are lower among women who are younger and have decreased over time. When asked if they would have a termination if their fetus tested positive, 23–33% said yes, when high-risk pregnant women were asked, 46–86% said yes, and when women who screened positive are asked, 89–97% say yes.",
"title": "Diagnosis"
},
{
"paragraph_id": 45,
"text": "The diagnosis can often be suspected based on the child's physical appearance at birth. Informing the parents of a diagnosis needs to be made as soon as possible, with care and sensitivity. Even an uncertain diagnosis needs to be informed of in the same way. This allows for a longer time for processing the information.",
"title": "Diagnosis"
},
{
"paragraph_id": 46,
"text": "An analysis of the child's chromosomes is needed to confirm the diagnosis, and to determine if a translocation is present, as this may help determine the chances of the child's parents having further children with Down syndrome.",
"title": "Diagnosis"
},
{
"paragraph_id": 47,
"text": "Efforts such as early childhood intervention, therapies, screening for common medical issues, a good family environment, and work-related training can improve the development of children with Down syndrome and provide good quality of life. Common therapies utilized include physical therapy, occupational therapy and speech therapy. Education and proper care can provide a positive quality of life. Typical childhood vaccinations are recommended.",
"title": "Management"
},
{
"paragraph_id": 48,
"text": "A number of health organizations have issued recommendations for screening those with Down syndrome for particular diseases. This is recommended to be done systematically.",
"title": "Management"
},
{
"paragraph_id": 49,
"text": "At birth, all children should get an electrocardiogram and ultrasound of the heart. Surgical repair of heart problems may be required as early as three months of age. Heart valve problems may occur in young adults, and further ultrasound evaluation may be needed in adolescents and in early adulthood. Due to the elevated risk of testicular cancer, some recommend checking the person's testicles yearly.",
"title": "Management"
},
{
"paragraph_id": 50,
"text": "Some people with Down syndrome experience hearing loss. In this instance, hearing aids or other amplification devices can be useful for language learning. Speech therapy may be useful and is recommended to be started around nine months of age. As those with Down syndrome typically have good hand-eye coordination, learning sign language is a helpful communication tool. Augmentative and alternative communication methods, such as pointing, body language, objects, or pictures, are often used to help with communication. Behavioral issues and mental illness are typically managed with counseling or medications.",
"title": "Management"
},
{
"paragraph_id": 51,
"text": "Education programs before reaching school age may be useful. School-age children with Down syndrome may benefit from inclusive education (whereby students of differing abilities are placed in classes with their peers of the same age), provided some adjustments are made to the curriculum. In the United States, the Individuals with Disabilities Education Act of 1975 requires public schools generally to allow attendance by students with Down syndrome.",
"title": "Management"
},
{
"paragraph_id": 52,
"text": "Individuals with Down syndrome may learn better visually. Drawing may help with language, speech, and reading skills. Children with Down syndrome still often have difficulty with sentence structure and grammar, as well as developing the ability to speak clearly. Several types of early intervention can help with cognitive development. Efforts to develop motor skills include physical therapy, speech and language therapy, and occupational therapy. Physical therapy focuses specifically on motor development and teaching children to interact with their environment. Speech and language therapy can help prepare for later language. Lastly, occupational therapy can help with skills needed for later independence.",
"title": "Management"
},
{
"paragraph_id": 53,
"text": "Tympanostomy tubes are often needed and often more than one set during the person's childhood. Tonsillectomy is also often done to help with sleep apnea and throat infections. Surgery does not correct every instance of sleep apnea and a continuous positive airway pressure (CPAP) machine may be useful in those cases.",
"title": "Management"
},
{
"paragraph_id": 54,
"text": "Efforts to prevent respiratory syncytial virus (RSV) infection with human monoclonal antibodies should be considered, especially in those with heart problems. In those who develop dementia there is no evidence for memantine, donepezil, rivastigmine, or galantamine.",
"title": "Management"
},
{
"paragraph_id": 55,
"text": "Between 5-15% of children with Down syndrome in Sweden attend regular school. Some graduate from high school; however, most do not. Of those with intellectual disability in the United States who attended high school about 40% graduated. Many learn to read and write and some are able to do paid work. In adulthood about 20% in the United States do paid work in some capacity. In Sweden, however, less than 1% have regular jobs. Many are able to live semi-independently, but they often require help with financial, medical, and legal matters. Those with mosaic Down syndrome usually have better outcomes.",
"title": "Prognosis"
},
{
"paragraph_id": 56,
"text": "Individuals with Down syndrome have a higher risk of early death than the general population. This is most often from heart problems or infections. Following improved medical care, particularly for heart and gastrointestinal problems, the life expectancy has increased. This increase has been from 12 years in 1912, to 25 years in the 1980s, to 50 to 60 years in the developed world in the 2000s. Data collected between the 1985–2003 showed between 4-12% infants with Down syndrome die in the first year of life. The probability of long-term survival is partly determined by the presence of heart problems. From research at the turn of the century, it tracked those with congenital heart problems, showing 60% survived to at least 10 years and 50% survived to at least 30 years of age. The research failed to track further aging beyond 30 years. In those without heart problems, 85% studied survived to at least 10 years and 80% survived to at least 30 years of age. It is estimated that 10% lived to 70 years of age in the early 2000s. Much of this data is outdated and life expectancy has drastically improved with more equitable healthcare and continuous advancement of surgical practice. The National Down Syndrome Society provides information regarding raising a child with Down syndrome.",
"title": "Prognosis"
},
{
"paragraph_id": 57,
"text": "Down syndrome is the most common chromosomal abnormality in humans. Globally, as of 2010, Down syndrome occurs in about 1 per 1,000 births and results in about 17,000 deaths. More children are born with Down syndrome in countries where abortion is not allowed and in countries where pregnancy more commonly occurs at a later age. About 1.4 per 1,000 live births in the United States and 1.1 per 1,000 live births in Norway are affected. In the 1950s, in the United States, it occurred in 2 per 1,000 live births with the decrease since then due to prenatal screening and abortions. The number of pregnancies with Down syndrome is more than two times greater with many spontaneously aborting. It is the cause of 8% of all congenital disorders.",
"title": "Epidemiology"
},
{
"paragraph_id": 58,
"text": "Maternal age affects the chances of having a pregnancy with Down syndrome. At age 20, the chance is 1 in 1,441; at age 30, it is 1 in 959; at age 40, it is 1 in 84; and at age 50 it is 1 in 44. Although the probability increases with maternal age, 70% of children with Down syndrome are born to women 35 years of age and younger, because younger people have more children. The father's older age is also a risk factor in women older than 35, but not in women younger than 35, and may partly explain the increase in risk as women age.",
"title": "Epidemiology"
},
{
"paragraph_id": 59,
"text": "English physician John Langdon Down first described Down syndrome in 1862, recognizing it as a distinct type of mental disability, and again in a more widely published report in 1866. Édouard Séguin described it as separate from cretinism in 1844. By the 20th century, Down syndrome had become the most recognizable form of mental disability.",
"title": "History"
},
{
"paragraph_id": 60,
"text": "Due to his perception that children with Down syndrome shared facial similarities with those of Blumenbach's Mongolian race, John Langdon Down used the term \"mongoloid\". He felt that the existence of Down syndrome confirmed that all peoples were genetically related. In the 1950s with discovery of the underlying cause as being related to chromosomes, concerns about the race-based nature of the name increased.",
"title": "History"
},
{
"paragraph_id": 61,
"text": "In 1961, a group of nineteen scientists suggested that \"mongolism\" had \"misleading connotations\" and had become \"an embarrassing term\". The World Health Organization (WHO) dropped the term in 1965 after a request by the delegation from the Mongolian People's Republic. While this racist terminology continued to be used until the late twentieth century, it is now considered unacceptable and is no longer in common use.",
"title": "History"
},
{
"paragraph_id": 62,
"text": "In antiquity, many infants with disabilities were either killed or abandoned. In June 2020, the earliest incidence of Down syndrome was found in genomic evidence from an infant that was buried before 3200 BC at Poulnabrone dolmen in Ireland. Researchers believe that a number of historical pieces of art portray Down syndrome, including pottery from the pre-Columbian Tumaco-La Tolita culture in present-day Colombia and Ecuador, and the 16th-century painting The Adoration of the Christ Child.",
"title": "History"
},
{
"paragraph_id": 63,
"text": "In the 20th century, many individuals with Down syndrome were institutionalized, few of the associated medical problems were treated, and most people died in infancy or early adulthood. With the rise of the eugenics movement, 33 of the then 48 U.S. states and several countries began programs of forced sterilization of individuals with Down syndrome and comparable degrees of disability. Action T4 in Nazi Germany saw the systematic murder of people with Down syndrome made public policy.",
"title": "History"
},
{
"paragraph_id": 64,
"text": "With the discovery of karyotype techniques in the 1950s it became possible to identify abnormalities of chromosomal number or shape. In 1959 Jérôme Lejeune reported the discovery that Down syndrome resulted from an extra chromosome. However, Lejeune's claim to the discovery has been disputed, and in 2014 the Scientific Council of the French Federation of Human Genetics unanimously awarded its Grand Prize to his colleague Marthe Gautier for her role in this discovery. The discovery took place in the laboratory of Raymond Turpin at the Hôpital Trousseau in Paris, France. Jérôme Lejeune and Marthe Gautier were both his students.",
"title": "History"
},
{
"paragraph_id": 65,
"text": "As a result of this discovery, the condition became known as trisomy 21. Even before the discovery of its cause, the presence of the syndrome in all races, its association with older maternal age, and its rarity of recurrence had been noticed. Medical texts had assumed it was caused by a combination of inheritable factors that had not been identified. Other theories had focused on injuries sustained during birth.",
"title": "History"
},
{
"paragraph_id": 66,
"text": "Down syndrome is named after John Langdon Down. He was the first person to provide an accurate description of the syndrome. His research that was published in 1866 earned him the recognition as the Father of the syndrome. While others had previously recognized components of the condition, John Langdon Down described the syndrome as a distinct, unique medical condition.",
"title": "Society and culture"
},
{
"paragraph_id": 67,
"text": "In 1975, the United States National Institutes of Health (NIH) convened a conference to standardize the naming and recommended replacing the possessive form, \"Down's syndrome\" with \"Down syndrome\". However, both the possessive and nonpossessive forms remain in use by the general population. The term \"trisomy 21\" is also commonly used.",
"title": "Society and culture"
},
{
"paragraph_id": 68,
"text": "Most obstetricians argue that not offering screening for Down syndrome is unethical. As it is a medically reasonable procedure, per informed consent, people should at least be given information about it. It will then be the woman's choice, based on her personal beliefs, how much or how little screening she wishes. When results from testing become available, it is also considered unethical not to give the results to the person in question.",
"title": "Society and culture"
},
{
"paragraph_id": 69,
"text": "Some bioethicists deem it reasonable for parents to select a child who would have the highest well-being. One criticism of this reasoning is that it often values those with disabilities less. Some parents argue that Down syndrome should not be prevented or cured and that eliminating Down syndrome amounts to genocide. The disability rights movement does not have a position on screening, although some members consider testing and abortion discriminatory. Some in the United States who are anti-abortion support abortion if the fetus is disabled, while others do not. Of a group of 40 mothers in the United States who have had one child with Down syndrome, half agreed to screening in the next pregnancy.",
"title": "Society and culture"
},
{
"paragraph_id": 70,
"text": "Within the US, some Protestant denominations see abortion as acceptable when a fetus has Down syndrome while Orthodox Christianity and Roman Catholicism do not. Some of those against screening refer to it as a form of eugenics. Disagreement exists within Islam regarding the acceptability of abortion in those carrying a fetus with Down syndrome. Some Islamic countries allow abortion, while others do not. Parents may be stigmatized whichever decision they make.",
"title": "Society and culture"
},
{
"paragraph_id": 71,
"text": "Advocacy groups for individuals with Down syndrome began to be formed after the Second World War. These were organizations advocating for the inclusion of people with Down syndrome into the general school system and for a greater understanding of the condition among the general population, as well as groups providing support for families with children living with Down syndrome. Before this individuals with Down syndrome were often placed in mental hospitals or asylums. Organizations included the Royal Society for Handicapped Children and Adults founded in the UK in 1946 by Judy Fryd, Kobato Kai founded in Japan in 1964, the National Down Syndrome Congress founded in the United States in 1973 by Kathryn McGee and others, and the National Down Syndrome Society founded in 1979 in the United States. The first Roman Catholic order of nuns for women with Down Syndrome, Little Sisters Disciples of the Lamb, was founded in 1985 in France.",
"title": "Society and culture"
},
{
"paragraph_id": 72,
"text": "The first World Down Syndrome Day was held on 21 March 2006. The day and month were chosen to correspond with 21 and trisomy, respectively. It was recognized by the United Nations General Assembly in 2011.",
"title": "Society and culture"
},
{
"paragraph_id": 73,
"text": "Efforts are underway to determine how the extra chromosome 21 material causes Down syndrome, as currently this is unknown, and to develop treatments to improve intelligence in those with the syndrome. Two efforts being studied are the use stem cells and gene therapy. Other methods being studied include the use of antioxidants, gamma secretase inhibition, adrenergic agonists, and memantine. Research is often carried out on an animal model, the Ts65Dn mouse.",
"title": "Research"
},
{
"paragraph_id": 74,
"text": "Down syndrome may also occur in hominids other than humans. In great apes chromosome 22 corresponds to the human chromosome 21 and thus trisomy 22 causes Down syndrome in apes. The condition was observed in a common chimpanzee in 1969 and a Bornean orangutan in 1979, but neither lived very long. The common chimpanzee Kanako (born around 1993, in Japan) has become the longest-lived known example of this condition. Kanako has some of the same symptoms that are common in human Down syndrome. It is unknown how common this condition is in chimps, but it is plausible it could be roughly as common as Down syndrome is in humans.",
"title": "Other hominids"
},
{
"paragraph_id": 75,
"text": "Individuals",
"title": "In popular culture"
},
{
"paragraph_id": 76,
"text": "Television and film",
"title": "In popular culture"
}
] | Down syndrome or Down's syndrome, also known as trisomy 21, is a genetic disorder caused by the presence of all or part of a third copy of chromosome 21. It is usually associated with developmental delays, mild to moderate intellectual disability, and characteristic physical features. There are three types of Down syndrome, all with the same features: Trisomy 21, the most common type; Mosaic Down syndrome, and Translocation Down syndrome. The parents of the affected individual are usually genetically normal. The probability increases from less than 0.1% in 20-year-old mothers to 3% in those of age 45. The extra chromosome is provided at conception as the egg and sperm combine. A very small percentage of 1-2% gets the additional chromosome in the embryo stage and it only impacts some of the cells in the body; this is known as Mosaic Down syndrome. Usually, babies get 23 chromosomes from each parent for a total of 46, whereas in Down syndrome, a third 21st chromosome is attached. It is believed to occur by chance, with no known behavioral activity or environmental factor that changes the probability. Down syndrome can be identified during pregnancy by prenatal screening, followed by diagnostic testing, or after birth by direct observation and genetic testing. Since the introduction of screening, Down syndrome pregnancies are often aborted. There is no cure for Down syndrome. Education and proper care have been shown to provide good quality of life. Some children with Down syndrome are educated in typical school classes, while others require more specialized education. Some individuals with Down syndrome graduate from high school, and a few attend post-secondary education. In adulthood, about 20% in the United States do paid work in some capacity, with many requiring a sheltered work environment. Support in financial and legal matters is often needed. Life expectancy is around 50 to 60 years in the developed world, with proper health care. Regular screening for health issues common in Down syndrome is recommended throughout the person's life. Down syndrome is the most common chromosomal abnormality. It occurs in about 1 in 1,000 babies born each year. In the US this figure is given as one in 700 births. In 2015, Down syndrome was present in 5.4 million individuals globally and resulted in 27,000 deaths, down from 43,000 deaths in 1990. It is named after British doctor John Langdon Down, who fully described the syndrome in 1866. Some aspects of the condition were described earlier by French psychiatrist Jean-Étienne Dominique Esquirol in 1838 and French physician Édouard Séguin in 1844. The genetic cause of Down syndrome was discovered in 1959. | 2001-08-11T10:54:08Z | 2023-12-27T18:59:40Z | [
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8,305 | Dyslexia | Dyslexia, previously known as word blindness, is a learning disability ('learning difficulty' in the UK) that affects either reading or writing. Different people are affected to different degrees. Problems may include difficulties in spelling words, reading quickly, writing words, "sounding out" words in the head, pronouncing words when reading aloud and understanding what one reads. Often these difficulties are first noticed at school. The difficulties are involuntary, and people with this disorder have a normal desire to learn. People with dyslexia have higher rates of attention deficit hyperactivity disorder (ADHD), developmental language disorders, and difficulties with numbers.
Dyslexia is believed to be caused by the interaction of genetic and environmental factors. Some cases run in families. Dyslexia that develops due to a traumatic brain injury, stroke, or dementia is sometimes called "acquired dyslexia" or alexia. The underlying mechanisms of dyslexia result from differences within the brain's language processing. Dyslexia is diagnosed through a series of tests of memory, vision, spelling, and reading skills. Dyslexia is separate from reading difficulties caused by hearing or vision problems or by insufficient teaching or opportunity to learn.
Treatment involves adjusting teaching methods to meet the person's needs. While not curing the underlying problem, it may decrease the degree or impact of symptoms. Treatments targeting vision are not effective. Dyslexia is the most common learning disability and occurs in all areas of the world. It affects 3–7% of the population; however, up to 20% of the general population may have some degree of symptoms. While dyslexia is more often diagnosed in boys, this is partly explained by a self-fulfilling referral bias among teachers and professionals. It has even been suggested that the condition affects men and women equally. Some believe that dyslexia is best considered as a different way of learning, with both benefits and downsides.
Dyslexia is divided into developmental and acquired forms. Acquired dyslexia occurs subsequent to neurological insult, such as traumatic brain injury or stroke. People with acquired dyslexia exhibit some of the signs or symptoms of the developmental disorder, but require different assessment strategies and treatment approaches. Pure alexia, also known as agnosic alexia or pure word blindness, is one form of alexia which makes up "the peripheral dyslexia" group.
In early childhood, symptoms that correlate with a later diagnosis of dyslexia include delayed onset of speech and a lack of phonological awareness. A common myth closely associates dyslexia with mirror writing and reading letters or words backwards. These behaviors are seen in many children as they learn to read and write, and are not considered to be defining characteristics of dyslexia.
School-age children with dyslexia may exhibit signs of difficulty in identifying or generating rhyming words, or counting the number of syllables in words—both of which depend on phonological awareness. They may also show difficulty in segmenting words into individual sounds (such as sounding out the three sounds of k, a, and t in cat) or may struggle to blend sounds, indicating reduced phonemic awareness.
Difficulties with word retrieval or naming things is also associated with dyslexia. People with dyslexia are commonly poor spellers, a feature sometimes called dysorthographia or dysgraphia, which depends on the skill of orthographic coding.
Problems persist into adolescence and adulthood and may include difficulties with summarizing stories, memorization, reading aloud, or learning foreign languages. Adults with dyslexia can often read with good comprehension, though they tend to read more slowly than others without a learning difficulty and perform worse in spelling tests or when reading nonsense words—a measure of phonological awareness.
Dyslexia often co-occurs with other learning disorders, but the reasons for this comorbidity have not been clearly identified. These associated disabilities include:
Researchers have been trying to find the neurobiological basis of dyslexia since the condition was first identified in 1881. For example, some have tried to associate the common problem among people with dyslexia of not being able to see letters clearly to abnormal development of their visual nerve cells.
Neuroimaging techniques, such as functional magnetic resonance imaging (fMRI) and positron emission tomography (PET), have shown a correlation between both functional and structural differences in the brains of children with reading difficulties. Some people with dyslexia show less activation in parts of the left hemisphere of the brain involved with reading, such as the inferior frontal gyrus, inferior parietal lobule, and the middle and ventral temporal cortex. Over the past decade, brain activation studies using PET to study language have produced a breakthrough in the understanding of the neural basis of language. Neural bases for the visual lexicon and for auditory verbal short-term memory components have been proposed, with some implication that the observed neural manifestation of developmental dyslexia is task-specific (i.e., functional rather than structural). fMRIs of people with dyslexia indicate an interactive role of the cerebellum and cerebral cortex as well as other brain structures in reading.
The cerebellar theory of dyslexia proposes that impairment of cerebellum-controlled muscle movement affects the formation of words by the tongue and facial muscles, resulting in the fluency problems that some people with dyslexia experience. The cerebellum is also involved in the automatization of some tasks, such as reading. The fact that some children with dyslexia have motor task and balance impairments could be consistent with a cerebellar role in their reading difficulties. However, the cerebellar theory has not been supported by controlled research studies.
Research into potential genetic causes of dyslexia has its roots in post-autopsy examination of the brains of people with dyslexia. Observed anatomical differences in the language centers of such brains include microscopic cortical malformations known as ectopias, and more rarely, vascular micro-malformations, and microgyrus—a smaller than usual size for the gyrus. The previously cited studies and others suggest that abnormal cortical development, presumed to occur before or during the sixth month of fetal brain development, may have caused the abnormalities. Abnormal cell formations in people with dyslexia have also been reported in non-language cerebral and subcortical brain structures. Several genes have been associated with dyslexia, including DCDC2 and KIAA0319 on chromosome 6, and DYX1C1 on chromosome 15.
The contribution of gene–environment interaction to reading disability has been intensely studied using twin studies, which estimate the proportion of variance associated with a person's environment and the proportion associated with their genes. Both environmental and genetic factors appear to contribute to reading development. Studies examining the influence of environmental factors such as parental education and teaching quality have determined that genetics have greater influence in supportive, rather than less optimal, environments. However, more optimal conditions may just allow those genetic risk factors to account for more of the variance in outcome because the environmental risk factors have been minimized.
As environment plays a large role in learning and memory, it is likely that epigenetic modifications play an important role in reading ability. Measures of gene expression, histone modifications, and methylation in the human periphery are used to study epigenetic processes; however, all of these have limitations in the extrapolation of results for application to the human brain.
The orthographic complexity of a language directly affects how difficult it is to learn to read it. English and French have comparatively "deep" phonemic orthographies within the Latin alphabet writing system, with complex structures employing spelling patterns on several levels: letter-sound correspondence, syllables, and morphemes. Languages such as Spanish, Italian and Finnish primarily employ letter-sound correspondence—so-called "shallow" orthographies—which makes them easier to learn for people with dyslexia. Logographic writing systems, such as Chinese characters, have extensive symbol use; and these also pose problems for dyslexic learners.
For most people who are right-hand dominant, the left hemisphere of their brain is more specialized for language processing. With regard to the mechanism of dyslexia, fMRI studies suggest that this specialization is less pronounced or absent in people with dyslexia. In other studies, dyslexia is correlated with anatomical differences in the corpus callosum, the bundle of nerve fibers that connects the left and right hemispheres.
Data via diffusion tensor MRI indicate changes in connectivity or in gray matter density in areas related to reading and language. Finally, the left inferior frontal gyrus has shown differences in phonological processing in people with dyslexia. Neurophysiological and imaging procedures are being used to ascertain phenotypic characteristics in people with dyslexia, thus identifying the effects of dyslexia-related genes.
The dual-route theory of reading aloud was first described in the early 1970s. This theory suggests that two separate mental mechanisms, or cognitive routes, are involved in reading aloud. One mechanism is the lexical route, which is the process whereby skilled readers can recognize known words by sight alone, through a "dictionary" lookup procedure. The other mechanism is the nonlexical or sublexical route, which is the process whereby the reader can "sound out" a written word. This is done by identifying the word's constituent parts (letters, phonemes, graphemes) and applying knowledge of how these parts are associated with each other, for example, how a string of neighboring letters sound together. The dual-route system could explain the different rates of dyslexia occurrence between different languages (e.g., the consistency of phonological rules in the Spanish language could account for the fact that Spanish-speaking children show a higher level of performance in non-word reading, when compared to English-speakers).
Dyslexia is a heterogeneous, dimensional learning disorder that impairs accurate and fluent word reading and spelling. Typical—but not universal—features include difficulties with phonological awareness; inefficient and often inaccurate processing of sounds in oral language (phonological processing); and verbal working memory deficits.
Dyslexia is a neurodevelopmental disorder, subcategorized in diagnostic guides as a learning disorder with impairment in reading (ICD-11 prefixes "developmental" to "learning disorder"; DSM-5 uses "specific"). Dyslexia is not a problem with intelligence. Emotional problems often arise secondary to learning difficulties. The National Institute of Neurological Disorders and Stroke describes dyslexia as "difficulty with phonological processing (the manipulation of sounds), spelling, and/or rapid visual-verbal responding".
The British Dyslexia Association defines dyslexia as "a learning difficulty that primarily affects the skills involved in accurate and fluent word reading and spelling" and is characterized by "difficulties in phonological awareness, verbal memory and verbal processing speed". Phonological awareness enables one to identify, discriminate, remember (working memory), and mentally manipulate the sound structures of language—phonemes, onsite-rime segments, syllables, and words.
The following can be done to assess for dyslexia:
Apply a multidisciplinary team approach involving the child's parent(s) and teacher(s), school psychologist, pediatrician, and, as appropriate, speech and language pathologist (speech therapist), and occupational therapist.
Gain familiarity with typical ages children reach various general developmental milestones, and domain-specific milestones, such as phonological awareness (recognizing rhyming words; identifying the initial sounds in words).
Do not rely on tests exclusively. Careful observation of the child in the school and home environments, and sensitive, comprehensive parental interviews are just as important as tests.
Look at the empirically supported response to intervention (RTI) approach, which "... involves monitoring the progress of a group of children through a programme of intervention rather than undertaking a static assessment of their current skills. Children with the most need are those who fail to respond to effective teaching, and they are readily identified using this approach."
There is a wide range of tests that are used in clinical and educational settings to evaluate the possibility of dyslexia. If initial testing suggests that a person might have dyslexia, such tests are often followed up with a full diagnostic assessment to determine the extent and nature of the disorder. Some tests can be administered by a teacher or computer; others require specialized training and are given by psychologists. Some test results indicate how to carry out teaching strategies. Because a variety of different cognitive, behavioral, emotional, and environmental factors all could contribute to difficultly learning to read, a comprehensive evaluation should consider these different possibilities. These tests and observations can include:
Screening procedures seek to identify children who show signs of possible dyslexia. In the preschool years, a family history of dyslexia, particularly in biological parents and siblings, predicts an eventual dyslexia diagnosis better than any test. In primary school (ages 5–7), the ideal screening procedure consists of training primary school teachers to carefully observe and record their pupils' progress through the phonics curriculum, and thereby identify children progressing slowly. When teachers identify such students they can supplement their observations with screening tests such as the Phonics screening check used by United Kingdom schools during Year one.
In the medical setting, child and adolescent psychiatrist M. S. Thambirajah emphasizes that "[g]iven the high prevalence of developmental disorders in school-aged children, all children seen in clinics should be systematically screened for developmental disorders irrespective of the presenting problem/s." Thambirajah recommends screening for developmental disorders, including dyslexia, by conducting a brief developmental history, a preliminary psychosocial developmental examination, and obtaining a school report regarding academic and social functioning.
Through the use of compensation strategies, therapy and educational support, individuals with dyslexia can learn to read and write. There are techniques and technical aids that help to manage or conceal symptoms of the disorder. Reducing stress and anxiety can sometimes improve written comprehension. For dyslexia intervention with alphabet-writing systems, the fundamental aim is to increase a child's awareness of correspondences between graphemes (letters) and phonemes (sounds), and to relate these to reading and spelling by teaching how sounds blend into words. Reinforced collateral training focused on reading and spelling may yield longer-lasting gains than oral phonological training alone. Early intervention can be successful in reducing reading failure.
Research does not suggest that specially-tailored fonts (such as Dyslexie and OpenDyslexic) help with reading. Children with dyslexia read text set in a regular font such as Times New Roman and Arial just as quickly, and they show a preference for regular fonts over specially-tailored fonts. Some research has pointed to increased letter-spacing being beneficial.
There is currently no evidence showing that music education significantly improves the reading skills of adolescents with dyslexia.
There is some evidence from an RCT that atomoxetine might be helpful for dyslexic with or without ADHD.
Dyslexic children require special instruction for word analysis and spelling from an early age. The prognosis, generally speaking, is positive for individuals who are identified in childhood and receive support from friends and family. The New York educational system (NYED) indicates "a daily uninterrupted 90-minute block of instruction in reading" and "instruction in phonemic awareness, phonics, vocabulary development, reading fluency" so as to improve the individual's reading ability.
The prevalence of dyslexia is unknown, but it has been estimated to be as low as 5% and as high as 17% of the population. Dyslexia is diagnosed more often in males.
There are different definitions of dyslexia used throughout the world. Further, differences in writing systems may affect development of written language ability due to the interplay between auditory and written representations of phonemes. Dyslexia is not limited to difficulty in converting letters to sounds, and Chinese people with dyslexia may have difficulty converting Chinese characters into their meanings. The Chinese vocabulary uses logographic, monographic, non-alphabet writing where one character can represent an individual phoneme.
The phonological-processing hypothesis attempts to explain why dyslexia occurs in a wide variety of languages. Furthermore, the relationship between phonological capacity and reading appears to be influenced by orthography.
Dyslexia was clinically described by Oswald Berkhan in 1881, but the term dyslexia was coined in 1883 by Rudolf Berlin, an ophthalmologist in Stuttgart. He used the term to refer to the case of a young boy who had severe difficulty learning to read and write, despite showing typical intelligence and physical abilities in all other respects. In 1896, W. Pringle Morgan, a British physician from Seaford, East Sussex, published a description of a reading-specific learning disorder in a report to the British Medical Journal titled "Congenital Word Blindness". The distinction between phonological versus surface types of dyslexia is only descriptive, and without any etiological assumption as to the underlying brain mechanisms. However, studies have alluded to potential differences due to variation in performance. Over time, we have changed from the intelligence-based model to the age-based model, in terms of those with Dyslexia.
As is the case with any disorder, society often makes an assessment based on incomplete information. Before the 1980s, dyslexia was thought to be a consequence of education, rather than a neurological disability. As a result, society often misjudges those with the disorder. There is also sometimes a workplace stigma and negative attitude towards those with dyslexia. If the instructors of a person with dyslexia lack the necessary training to support a child with the condition, there is often a negative effect on the student's learning participation.
Since at least the 1960s in the UK, the children diagnosed with developmental dyslexia have consistently been from privileged families. Although half of prisoners in the UK have significant reading difficulties, very few have ever been evaluated for dyslexia. Access to some special educational resources and funding is contingent upon having a diagnosis of dyslexia. As a result, when Staffordshire and Warwickshire proposed in 2018 to teach reading to all children with reading difficulties, using techniques proven to be successful for most children with a diagnosis of dyslexia, without first requiring the families to obtain an official diagnosis, dyslexia advocates and parents of children with dyslexia were fearful that they were losing a privileged status.
Due to the various cognitive processes that dyslexia affects and the overwhelming societal stigma around the disability, individuals with dyslexia often employ behaviors of self-stigma and perfectionistic self-presentation in order to cope with their disability. The perfectionist self-presentation is when an individual attempts to present themselves as the perfect ideal image and hides any imperfections. This behavior presents serious risk as it often results in mental health issues and refusal to seek help for their disability.
Most dyslexia research relates to alphabetic writing systems, and especially to European languages. However, substantial research is also available regarding people with dyslexia who speak Arabic, Chinese, Hebrew, or other languages. The outward expression of individuals with reading disability, and regular poor readers, is the same in some respects.
This article was submitted to WikiJournal of Medicine for external academic peer review in 2018 (reviewer reports). The updated content was reintegrated into the Wikipedia page under a CC-BY-SA-3.0 license (2019). The version of record as reviewed is: Osmin Anis; et al. (15 October 2019). "Dyslexia" (PDF). WikiJournal of Medicine. 6 (1): 5. doi:10.15347/WJM/2019.005. ISSN 2002-4436. Wikidata Q73053061. | [
{
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"text": "Dyslexia, previously known as word blindness, is a learning disability ('learning difficulty' in the UK) that affects either reading or writing. Different people are affected to different degrees. Problems may include difficulties in spelling words, reading quickly, writing words, \"sounding out\" words in the head, pronouncing words when reading aloud and understanding what one reads. Often these difficulties are first noticed at school. The difficulties are involuntary, and people with this disorder have a normal desire to learn. People with dyslexia have higher rates of attention deficit hyperactivity disorder (ADHD), developmental language disorders, and difficulties with numbers.",
"title": ""
},
{
"paragraph_id": 1,
"text": "Dyslexia is believed to be caused by the interaction of genetic and environmental factors. Some cases run in families. Dyslexia that develops due to a traumatic brain injury, stroke, or dementia is sometimes called \"acquired dyslexia\" or alexia. The underlying mechanisms of dyslexia result from differences within the brain's language processing. Dyslexia is diagnosed through a series of tests of memory, vision, spelling, and reading skills. Dyslexia is separate from reading difficulties caused by hearing or vision problems or by insufficient teaching or opportunity to learn.",
"title": ""
},
{
"paragraph_id": 2,
"text": "Treatment involves adjusting teaching methods to meet the person's needs. While not curing the underlying problem, it may decrease the degree or impact of symptoms. Treatments targeting vision are not effective. Dyslexia is the most common learning disability and occurs in all areas of the world. It affects 3–7% of the population; however, up to 20% of the general population may have some degree of symptoms. While dyslexia is more often diagnosed in boys, this is partly explained by a self-fulfilling referral bias among teachers and professionals. It has even been suggested that the condition affects men and women equally. Some believe that dyslexia is best considered as a different way of learning, with both benefits and downsides.",
"title": ""
},
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"paragraph_id": 3,
"text": "Dyslexia is divided into developmental and acquired forms. Acquired dyslexia occurs subsequent to neurological insult, such as traumatic brain injury or stroke. People with acquired dyslexia exhibit some of the signs or symptoms of the developmental disorder, but require different assessment strategies and treatment approaches. Pure alexia, also known as agnosic alexia or pure word blindness, is one form of alexia which makes up \"the peripheral dyslexia\" group.",
"title": "Classification"
},
{
"paragraph_id": 4,
"text": "In early childhood, symptoms that correlate with a later diagnosis of dyslexia include delayed onset of speech and a lack of phonological awareness. A common myth closely associates dyslexia with mirror writing and reading letters or words backwards. These behaviors are seen in many children as they learn to read and write, and are not considered to be defining characteristics of dyslexia.",
"title": "Signs and symptoms"
},
{
"paragraph_id": 5,
"text": "School-age children with dyslexia may exhibit signs of difficulty in identifying or generating rhyming words, or counting the number of syllables in words—both of which depend on phonological awareness. They may also show difficulty in segmenting words into individual sounds (such as sounding out the three sounds of k, a, and t in cat) or may struggle to blend sounds, indicating reduced phonemic awareness.",
"title": "Signs and symptoms"
},
{
"paragraph_id": 6,
"text": "Difficulties with word retrieval or naming things is also associated with dyslexia. People with dyslexia are commonly poor spellers, a feature sometimes called dysorthographia or dysgraphia, which depends on the skill of orthographic coding.",
"title": "Signs and symptoms"
},
{
"paragraph_id": 7,
"text": "Problems persist into adolescence and adulthood and may include difficulties with summarizing stories, memorization, reading aloud, or learning foreign languages. Adults with dyslexia can often read with good comprehension, though they tend to read more slowly than others without a learning difficulty and perform worse in spelling tests or when reading nonsense words—a measure of phonological awareness.",
"title": "Signs and symptoms"
},
{
"paragraph_id": 8,
"text": "Dyslexia often co-occurs with other learning disorders, but the reasons for this comorbidity have not been clearly identified. These associated disabilities include:",
"title": "Signs and symptoms"
},
{
"paragraph_id": 9,
"text": "Researchers have been trying to find the neurobiological basis of dyslexia since the condition was first identified in 1881. For example, some have tried to associate the common problem among people with dyslexia of not being able to see letters clearly to abnormal development of their visual nerve cells.",
"title": "Causes"
},
{
"paragraph_id": 10,
"text": "Neuroimaging techniques, such as functional magnetic resonance imaging (fMRI) and positron emission tomography (PET), have shown a correlation between both functional and structural differences in the brains of children with reading difficulties. Some people with dyslexia show less activation in parts of the left hemisphere of the brain involved with reading, such as the inferior frontal gyrus, inferior parietal lobule, and the middle and ventral temporal cortex. Over the past decade, brain activation studies using PET to study language have produced a breakthrough in the understanding of the neural basis of language. Neural bases for the visual lexicon and for auditory verbal short-term memory components have been proposed, with some implication that the observed neural manifestation of developmental dyslexia is task-specific (i.e., functional rather than structural). fMRIs of people with dyslexia indicate an interactive role of the cerebellum and cerebral cortex as well as other brain structures in reading.",
"title": "Causes"
},
{
"paragraph_id": 11,
"text": "The cerebellar theory of dyslexia proposes that impairment of cerebellum-controlled muscle movement affects the formation of words by the tongue and facial muscles, resulting in the fluency problems that some people with dyslexia experience. The cerebellum is also involved in the automatization of some tasks, such as reading. The fact that some children with dyslexia have motor task and balance impairments could be consistent with a cerebellar role in their reading difficulties. However, the cerebellar theory has not been supported by controlled research studies.",
"title": "Causes"
},
{
"paragraph_id": 12,
"text": "Research into potential genetic causes of dyslexia has its roots in post-autopsy examination of the brains of people with dyslexia. Observed anatomical differences in the language centers of such brains include microscopic cortical malformations known as ectopias, and more rarely, vascular micro-malformations, and microgyrus—a smaller than usual size for the gyrus. The previously cited studies and others suggest that abnormal cortical development, presumed to occur before or during the sixth month of fetal brain development, may have caused the abnormalities. Abnormal cell formations in people with dyslexia have also been reported in non-language cerebral and subcortical brain structures. Several genes have been associated with dyslexia, including DCDC2 and KIAA0319 on chromosome 6, and DYX1C1 on chromosome 15.",
"title": "Causes"
},
{
"paragraph_id": 13,
"text": "The contribution of gene–environment interaction to reading disability has been intensely studied using twin studies, which estimate the proportion of variance associated with a person's environment and the proportion associated with their genes. Both environmental and genetic factors appear to contribute to reading development. Studies examining the influence of environmental factors such as parental education and teaching quality have determined that genetics have greater influence in supportive, rather than less optimal, environments. However, more optimal conditions may just allow those genetic risk factors to account for more of the variance in outcome because the environmental risk factors have been minimized.",
"title": "Causes"
},
{
"paragraph_id": 14,
"text": "As environment plays a large role in learning and memory, it is likely that epigenetic modifications play an important role in reading ability. Measures of gene expression, histone modifications, and methylation in the human periphery are used to study epigenetic processes; however, all of these have limitations in the extrapolation of results for application to the human brain.",
"title": "Causes"
},
{
"paragraph_id": 15,
"text": "The orthographic complexity of a language directly affects how difficult it is to learn to read it. English and French have comparatively \"deep\" phonemic orthographies within the Latin alphabet writing system, with complex structures employing spelling patterns on several levels: letter-sound correspondence, syllables, and morphemes. Languages such as Spanish, Italian and Finnish primarily employ letter-sound correspondence—so-called \"shallow\" orthographies—which makes them easier to learn for people with dyslexia. Logographic writing systems, such as Chinese characters, have extensive symbol use; and these also pose problems for dyslexic learners.",
"title": "Causes"
},
{
"paragraph_id": 16,
"text": "For most people who are right-hand dominant, the left hemisphere of their brain is more specialized for language processing. With regard to the mechanism of dyslexia, fMRI studies suggest that this specialization is less pronounced or absent in people with dyslexia. In other studies, dyslexia is correlated with anatomical differences in the corpus callosum, the bundle of nerve fibers that connects the left and right hemispheres.",
"title": "Pathophysiology"
},
{
"paragraph_id": 17,
"text": "Data via diffusion tensor MRI indicate changes in connectivity or in gray matter density in areas related to reading and language. Finally, the left inferior frontal gyrus has shown differences in phonological processing in people with dyslexia. Neurophysiological and imaging procedures are being used to ascertain phenotypic characteristics in people with dyslexia, thus identifying the effects of dyslexia-related genes.",
"title": "Pathophysiology"
},
{
"paragraph_id": 18,
"text": "The dual-route theory of reading aloud was first described in the early 1970s. This theory suggests that two separate mental mechanisms, or cognitive routes, are involved in reading aloud. One mechanism is the lexical route, which is the process whereby skilled readers can recognize known words by sight alone, through a \"dictionary\" lookup procedure. The other mechanism is the nonlexical or sublexical route, which is the process whereby the reader can \"sound out\" a written word. This is done by identifying the word's constituent parts (letters, phonemes, graphemes) and applying knowledge of how these parts are associated with each other, for example, how a string of neighboring letters sound together. The dual-route system could explain the different rates of dyslexia occurrence between different languages (e.g., the consistency of phonological rules in the Spanish language could account for the fact that Spanish-speaking children show a higher level of performance in non-word reading, when compared to English-speakers).",
"title": "Pathophysiology"
},
{
"paragraph_id": 19,
"text": "Dyslexia is a heterogeneous, dimensional learning disorder that impairs accurate and fluent word reading and spelling. Typical—but not universal—features include difficulties with phonological awareness; inefficient and often inaccurate processing of sounds in oral language (phonological processing); and verbal working memory deficits.",
"title": "Diagnosis"
},
{
"paragraph_id": 20,
"text": "Dyslexia is a neurodevelopmental disorder, subcategorized in diagnostic guides as a learning disorder with impairment in reading (ICD-11 prefixes \"developmental\" to \"learning disorder\"; DSM-5 uses \"specific\"). Dyslexia is not a problem with intelligence. Emotional problems often arise secondary to learning difficulties. The National Institute of Neurological Disorders and Stroke describes dyslexia as \"difficulty with phonological processing (the manipulation of sounds), spelling, and/or rapid visual-verbal responding\".",
"title": "Diagnosis"
},
{
"paragraph_id": 21,
"text": "The British Dyslexia Association defines dyslexia as \"a learning difficulty that primarily affects the skills involved in accurate and fluent word reading and spelling\" and is characterized by \"difficulties in phonological awareness, verbal memory and verbal processing speed\". Phonological awareness enables one to identify, discriminate, remember (working memory), and mentally manipulate the sound structures of language—phonemes, onsite-rime segments, syllables, and words.",
"title": "Diagnosis"
},
{
"paragraph_id": 22,
"text": "The following can be done to assess for dyslexia:",
"title": "Diagnosis"
},
{
"paragraph_id": 23,
"text": "Apply a multidisciplinary team approach involving the child's parent(s) and teacher(s), school psychologist, pediatrician, and, as appropriate, speech and language pathologist (speech therapist), and occupational therapist.",
"title": "Diagnosis"
},
{
"paragraph_id": 24,
"text": "Gain familiarity with typical ages children reach various general developmental milestones, and domain-specific milestones, such as phonological awareness (recognizing rhyming words; identifying the initial sounds in words).",
"title": "Diagnosis"
},
{
"paragraph_id": 25,
"text": "Do not rely on tests exclusively. Careful observation of the child in the school and home environments, and sensitive, comprehensive parental interviews are just as important as tests.",
"title": "Diagnosis"
},
{
"paragraph_id": 26,
"text": "Look at the empirically supported response to intervention (RTI) approach, which \"... involves monitoring the progress of a group of children through a programme of intervention rather than undertaking a static assessment of their current skills. Children with the most need are those who fail to respond to effective teaching, and they are readily identified using this approach.\"",
"title": "Diagnosis"
},
{
"paragraph_id": 27,
"text": "There is a wide range of tests that are used in clinical and educational settings to evaluate the possibility of dyslexia. If initial testing suggests that a person might have dyslexia, such tests are often followed up with a full diagnostic assessment to determine the extent and nature of the disorder. Some tests can be administered by a teacher or computer; others require specialized training and are given by psychologists. Some test results indicate how to carry out teaching strategies. Because a variety of different cognitive, behavioral, emotional, and environmental factors all could contribute to difficultly learning to read, a comprehensive evaluation should consider these different possibilities. These tests and observations can include:",
"title": "Diagnosis"
},
{
"paragraph_id": 28,
"text": "Screening procedures seek to identify children who show signs of possible dyslexia. In the preschool years, a family history of dyslexia, particularly in biological parents and siblings, predicts an eventual dyslexia diagnosis better than any test. In primary school (ages 5–7), the ideal screening procedure consists of training primary school teachers to carefully observe and record their pupils' progress through the phonics curriculum, and thereby identify children progressing slowly. When teachers identify such students they can supplement their observations with screening tests such as the Phonics screening check used by United Kingdom schools during Year one.",
"title": "Screening"
},
{
"paragraph_id": 29,
"text": "In the medical setting, child and adolescent psychiatrist M. S. Thambirajah emphasizes that \"[g]iven the high prevalence of developmental disorders in school-aged children, all children seen in clinics should be systematically screened for developmental disorders irrespective of the presenting problem/s.\" Thambirajah recommends screening for developmental disorders, including dyslexia, by conducting a brief developmental history, a preliminary psychosocial developmental examination, and obtaining a school report regarding academic and social functioning.",
"title": "Screening"
},
{
"paragraph_id": 30,
"text": "Through the use of compensation strategies, therapy and educational support, individuals with dyslexia can learn to read and write. There are techniques and technical aids that help to manage or conceal symptoms of the disorder. Reducing stress and anxiety can sometimes improve written comprehension. For dyslexia intervention with alphabet-writing systems, the fundamental aim is to increase a child's awareness of correspondences between graphemes (letters) and phonemes (sounds), and to relate these to reading and spelling by teaching how sounds blend into words. Reinforced collateral training focused on reading and spelling may yield longer-lasting gains than oral phonological training alone. Early intervention can be successful in reducing reading failure.",
"title": "Management"
},
{
"paragraph_id": 31,
"text": "Research does not suggest that specially-tailored fonts (such as Dyslexie and OpenDyslexic) help with reading. Children with dyslexia read text set in a regular font such as Times New Roman and Arial just as quickly, and they show a preference for regular fonts over specially-tailored fonts. Some research has pointed to increased letter-spacing being beneficial.",
"title": "Management"
},
{
"paragraph_id": 32,
"text": "There is currently no evidence showing that music education significantly improves the reading skills of adolescents with dyslexia.",
"title": "Management"
},
{
"paragraph_id": 33,
"text": "There is some evidence from an RCT that atomoxetine might be helpful for dyslexic with or without ADHD.",
"title": "Management"
},
{
"paragraph_id": 34,
"text": "Dyslexic children require special instruction for word analysis and spelling from an early age. The prognosis, generally speaking, is positive for individuals who are identified in childhood and receive support from friends and family. The New York educational system (NYED) indicates \"a daily uninterrupted 90-minute block of instruction in reading\" and \"instruction in phonemic awareness, phonics, vocabulary development, reading fluency\" so as to improve the individual's reading ability.",
"title": "Prognosis"
},
{
"paragraph_id": 35,
"text": "The prevalence of dyslexia is unknown, but it has been estimated to be as low as 5% and as high as 17% of the population. Dyslexia is diagnosed more often in males.",
"title": "Epidemiology"
},
{
"paragraph_id": 36,
"text": "There are different definitions of dyslexia used throughout the world. Further, differences in writing systems may affect development of written language ability due to the interplay between auditory and written representations of phonemes. Dyslexia is not limited to difficulty in converting letters to sounds, and Chinese people with dyslexia may have difficulty converting Chinese characters into their meanings. The Chinese vocabulary uses logographic, monographic, non-alphabet writing where one character can represent an individual phoneme.",
"title": "Epidemiology"
},
{
"paragraph_id": 37,
"text": "The phonological-processing hypothesis attempts to explain why dyslexia occurs in a wide variety of languages. Furthermore, the relationship between phonological capacity and reading appears to be influenced by orthography.",
"title": "Epidemiology"
},
{
"paragraph_id": 38,
"text": "Dyslexia was clinically described by Oswald Berkhan in 1881, but the term dyslexia was coined in 1883 by Rudolf Berlin, an ophthalmologist in Stuttgart. He used the term to refer to the case of a young boy who had severe difficulty learning to read and write, despite showing typical intelligence and physical abilities in all other respects. In 1896, W. Pringle Morgan, a British physician from Seaford, East Sussex, published a description of a reading-specific learning disorder in a report to the British Medical Journal titled \"Congenital Word Blindness\". The distinction between phonological versus surface types of dyslexia is only descriptive, and without any etiological assumption as to the underlying brain mechanisms. However, studies have alluded to potential differences due to variation in performance. Over time, we have changed from the intelligence-based model to the age-based model, in terms of those with Dyslexia.",
"title": "History"
},
{
"paragraph_id": 39,
"text": "As is the case with any disorder, society often makes an assessment based on incomplete information. Before the 1980s, dyslexia was thought to be a consequence of education, rather than a neurological disability. As a result, society often misjudges those with the disorder. There is also sometimes a workplace stigma and negative attitude towards those with dyslexia. If the instructors of a person with dyslexia lack the necessary training to support a child with the condition, there is often a negative effect on the student's learning participation.",
"title": "Society and culture"
},
{
"paragraph_id": 40,
"text": "Since at least the 1960s in the UK, the children diagnosed with developmental dyslexia have consistently been from privileged families. Although half of prisoners in the UK have significant reading difficulties, very few have ever been evaluated for dyslexia. Access to some special educational resources and funding is contingent upon having a diagnosis of dyslexia. As a result, when Staffordshire and Warwickshire proposed in 2018 to teach reading to all children with reading difficulties, using techniques proven to be successful for most children with a diagnosis of dyslexia, without first requiring the families to obtain an official diagnosis, dyslexia advocates and parents of children with dyslexia were fearful that they were losing a privileged status.",
"title": "Society and culture"
},
{
"paragraph_id": 41,
"text": "Due to the various cognitive processes that dyslexia affects and the overwhelming societal stigma around the disability, individuals with dyslexia often employ behaviors of self-stigma and perfectionistic self-presentation in order to cope with their disability. The perfectionist self-presentation is when an individual attempts to present themselves as the perfect ideal image and hides any imperfections. This behavior presents serious risk as it often results in mental health issues and refusal to seek help for their disability.",
"title": "Society and culture"
},
{
"paragraph_id": 42,
"text": "Most dyslexia research relates to alphabetic writing systems, and especially to European languages. However, substantial research is also available regarding people with dyslexia who speak Arabic, Chinese, Hebrew, or other languages. The outward expression of individuals with reading disability, and regular poor readers, is the same in some respects.",
"title": "Research"
},
{
"paragraph_id": 43,
"text": "This article was submitted to WikiJournal of Medicine for external academic peer review in 2018 (reviewer reports). The updated content was reintegrated into the Wikipedia page under a CC-BY-SA-3.0 license (2019). The version of record as reviewed is: Osmin Anis; et al. (15 October 2019). \"Dyslexia\" (PDF). WikiJournal of Medicine. 6 (1): 5. doi:10.15347/WJM/2019.005. ISSN 2002-4436. Wikidata Q73053061.",
"title": "References"
}
] | Dyslexia, previously known as word blindness, is a learning disability that affects either reading or writing. Different people are affected to different degrees. Problems may include difficulties in spelling words, reading quickly, writing words, "sounding out" words in the head, pronouncing words when reading aloud and understanding what one reads. Often these difficulties are first noticed at school. The difficulties are involuntary, and people with this disorder have a normal desire to learn. People with dyslexia have higher rates of attention deficit hyperactivity disorder (ADHD), developmental language disorders, and difficulties with numbers. Dyslexia is believed to be caused by the interaction of genetic and environmental factors. Some cases run in families. Dyslexia that develops due to a traumatic brain injury, stroke, or dementia is sometimes called "acquired dyslexia" or alexia. The underlying mechanisms of dyslexia result from differences within the brain's language processing. Dyslexia is diagnosed through a series of tests of memory, vision, spelling, and reading skills. Dyslexia is separate from reading difficulties caused by hearing or vision problems or by insufficient teaching or opportunity to learn. Treatment involves adjusting teaching methods to meet the person's needs. While not curing the underlying problem, it may decrease the degree or impact of symptoms. Treatments targeting vision are not effective. Dyslexia is the most common learning disability and occurs in all areas of the world. It affects 3–7% of the population; however, up to 20% of the general population may have some degree of symptoms. While dyslexia is more often diagnosed in boys, this is partly explained by a self-fulfilling referral bias among teachers and professionals. It has even been suggested that the condition affects men and women equally. Some believe that dyslexia is best considered as a different way of learning, with both benefits and downsides. | 2001-08-11T11:54:03Z | 2023-12-25T19:01:41Z | [
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] | https://en.wikipedia.org/wiki/Dyslexia |
8,308 | Delft | Delft (Dutch pronunciation: [ˈdɛl(ə)ft] ) is a city and municipality in the province of South Holland, Netherlands. It is located between Rotterdam, to the southeast, and The Hague, to the northwest. Together with them, it is a part of both the Rotterdam–The Hague metropolitan area and the Randstad.
Delft is a popular tourist destination in the Netherlands, famous for its historical connections with the reigning House of Orange-Nassau, for its blue pottery, for being home to the painter Jan Vermeer, and for hosting Delft University of Technology (TU Delft). Historically, Delft played a highly influential role in the Dutch Golden Age. In terms of science and technology, thanks to the pioneering contributions of Antonie van Leeuwenhoek and Martinus Beijerinck, Delft can be considered to be the birthplace of microbiology.
The city of Delft came into being beside a canal, the 'Delf', which comes from the word delven, meaning to delve or dig, and this led to the name Delft. At the elevated place where this 'Delf' crossed the creek wall of the silted up river Gantel, a Count established his manor, probably around 1075. Partly because of this, Delft became an important market town, the evidence for which can be seen in the size of its central market square.
Having been a rural village in the early Middle Ages, Delft developed into a city, and on 15 April 1246, Count Willem II granted Delft its city charter. Trade and industry flourished. In 1389 the Delfshavensche Schie canal was dug through to the river Maas, where the port of Delfshaven was built, connecting Delft to the sea.
Until the 17th century, Delft was one of the major cities of the then county (and later province) of Holland. In 1400, for example, the city had 6,500 inhabitants, making it the third largest city after Dordrecht (8,000) and Haarlem (7,000). In 1560, Amsterdam, with 28,000 inhabitants, had become the largest city, followed by Delft, Leiden and Haarlem, which each had around 14,000 inhabitants.
In 1536, a large part of the city was destroyed by the great fire of Delft.
The town's association with the House of Orange started when William of Orange (Willem van Oranje), nicknamed William the Silent (Willem de Zwijger), took up residence in 1572 in the former Saint-Agatha convent (subsequently called the Prinsenhof). At the time he was the leader of growing national Dutch resistance against Spanish occupation, known as the Eighty Years' War. By then Delft was one of the leading cities of Holland and was equipped with the necessary city walls to serve as a headquarters. In October 1573, an attack by Spanish forces was repelled in the Battle of Delft.
After the Act of Abjuration was proclaimed in 1581, Delft became the de facto capital of the newly independent Netherlands, as the seat of the Prince of Orange.
When William was shot dead on 10 July 1584 by Balthazar Gerards in the hall of the Prinsenhof (now the Prinsenhof Museum), the family's traditional burial place in Breda was still in the hands of the Spanish. Therefore, he was buried in the Delft Nieuwe Kerk (New Church), starting a tradition for the House of Orange that has continued to the present day.
Around this time, Delft also occupied a prominent position in the field of printing.
A number of Italian glazed earthenware makers settled in the city and introduced a new style. The tapestry industry also flourished when famous manufacturer François Spierincx moved to the city. In the 17th century, Delft experienced a new heyday, thanks to the presence of an office of the Dutch East India Company (VOC) (opened in 1602) and the manufacture of Delft Blue china.
A number of notable artists based themselves in the city, including Leonard Bramer, Carel Fabritius, Pieter de Hoogh, Gerard Houckgeest, Emanuel de Witte, Jan Steen, and Johannes Vermeer. Reinier de Graaf and Antonie van Leeuwenhoek received international attention for their scientific research.
The Delft Explosion, also known in history as the Delft Thunderclap, occurred on 12 October 1654 when a gunpowder store exploded, destroying much of the city. Over a hundred people were killed and thousands were injured.
About 30 t (29.5 long tons; 33.1 short tons) of gunpowder were stored in barrels in a magazine in a former Clarist convent in the Doelenkwartier district, where the Paardenmarkt is now located. Cornelis Soetens, the keeper of the magazine, opened the store to check a sample of the powder and a huge explosion followed. Luckily, many citizens were away, visiting a market in Schiedam or a fair in The Hague.
Today, the explosion is primarily remembered for killing Rembrandt's most promising pupil, Carel Fabritius, and destroying almost all of his works.
Delft artist Egbert van der Poel painted several pictures of Delft showing the devastation.
The gunpowder store (Dutch: Kruithuis) was subsequently re-housed, a 'cannonball's distance away', outside the city, in a new building designed by architect Pieter Post.
The city centre retains a large number of monumental buildings, while in many streets there are canals of which the banks are connected by typical bridges, altogether making this city a notable tourist destination.
Historical buildings and other sights of interest include:
Delft is well known for the Delft pottery ceramic products which were styled on the imported Chinese porcelain of the 17th century. The city had an early start in this area since it was a home port of the Dutch East India Company. It can still be seen at the pottery factories De Koninklijke Porceleyne Fles (or Royal Delft) and De Delftse Pauw, while new ceramics and ceramic art can be found at the Gallery Terra Delft.
The painter Johannes Vermeer (1632–1675) was born in Delft. Vermeer used Delft streets and home interiors as the subject or background in his paintings. Several other famous painters lived and worked in Delft at that time, such as Pieter de Hoogh, Carel Fabritius, Nicolaes Maes, Gerard Houckgeest and Hendrick Cornelisz. van Vliet. They were all members of the Delft School. The Delft School is known for its images of domestic life and views of households, church interiors, courtyards, squares and the streets of Delft. The painters also produced pictures showing historic events, flowers, portraits for patrons and the court as well as decorative pieces of art.
Delft supports creative arts' companies. From 2001 the Bacinol [nl], a building that had been disused since 1951, began to house small companies in the creative arts sector. Its demolition started in December 2009, making way for the new railway tunnel in Delft. The occupants of the building, as well as the name 'Bacinol', moved to another building in the city. The name Bacinol relates to Dutch penicillin research during WWII.
Delft University of Technology (TU Delft) is one of four universities of technology in the Netherlands. It was founded as an academy for civil engineering in 1842 by King William II. Today, well over 21,000 students are enrolled.
The UNESCO-IHE Institute for Water Education, providing postgraduate education for people from developing countries, draws on the strong tradition in water management and hydraulic engineering of the Delft university.
The Hague University of Applied Sciences has a building on the Delft University of Technology campus. It opened in 2009 and offers several bachelor degrees for the Faculty of Technology, Innovation & Society.
Inholland University of Applied Sciences also has a building on the Delft University of Technology campus. Several bachelor degrees for the Agri, Food & Life Sciences faculty and the Engineering, Design and Computing faculty are being taught at the Delft campus.
In the local economic field, essential elements are:
East of Delft lies a relatively large nature and recreation area called the "Delftse Hout" ("Delft Wood"). Through the forest lie bike, horse-riding and footpaths. It also includes a vast lake (suitable for swimming and windsurfing), narrow beaches, a restaurant, and community gardens, plus camping ground and other recreational and sports facilities. (There is also a facility for renting bikes from the station.)
Inside the city, apart from a central park, there are several smaller town parks, including "Nieuwe Plantage", "Agnetapark", "Kalverbos". There is also the Botanical Garden of the TU and an arboretum in Delftse Hout.
Delft is the birthplace of:
Delft is twinned with:
Trains stopping at these stations connect Delft with, among others, the nearby cities of Rotterdam and The Hague, as often as every five minutes, for most of the day.
There are several bus routes from Delft to similar destinations. Trams frequently travel between Delft and The Hague via special double tracks crossing the city.
The whole city center and adjacent areas are a paid on-street parking area. In 2018, with the day parking fee of 29.5 Euro, it was the most expensive on-street parking area in the Netherlands, with the city centers of Deventer and Dordrecht being second and third, respectively. | [
{
"paragraph_id": 0,
"text": "Delft (Dutch pronunciation: [ˈdɛl(ə)ft] ) is a city and municipality in the province of South Holland, Netherlands. It is located between Rotterdam, to the southeast, and The Hague, to the northwest. Together with them, it is a part of both the Rotterdam–The Hague metropolitan area and the Randstad.",
"title": ""
},
{
"paragraph_id": 1,
"text": "Delft is a popular tourist destination in the Netherlands, famous for its historical connections with the reigning House of Orange-Nassau, for its blue pottery, for being home to the painter Jan Vermeer, and for hosting Delft University of Technology (TU Delft). Historically, Delft played a highly influential role in the Dutch Golden Age. In terms of science and technology, thanks to the pioneering contributions of Antonie van Leeuwenhoek and Martinus Beijerinck, Delft can be considered to be the birthplace of microbiology.",
"title": ""
},
{
"paragraph_id": 2,
"text": "The city of Delft came into being beside a canal, the 'Delf', which comes from the word delven, meaning to delve or dig, and this led to the name Delft. At the elevated place where this 'Delf' crossed the creek wall of the silted up river Gantel, a Count established his manor, probably around 1075. Partly because of this, Delft became an important market town, the evidence for which can be seen in the size of its central market square.",
"title": "History"
},
{
"paragraph_id": 3,
"text": "Having been a rural village in the early Middle Ages, Delft developed into a city, and on 15 April 1246, Count Willem II granted Delft its city charter. Trade and industry flourished. In 1389 the Delfshavensche Schie canal was dug through to the river Maas, where the port of Delfshaven was built, connecting Delft to the sea.",
"title": "History"
},
{
"paragraph_id": 4,
"text": "Until the 17th century, Delft was one of the major cities of the then county (and later province) of Holland. In 1400, for example, the city had 6,500 inhabitants, making it the third largest city after Dordrecht (8,000) and Haarlem (7,000). In 1560, Amsterdam, with 28,000 inhabitants, had become the largest city, followed by Delft, Leiden and Haarlem, which each had around 14,000 inhabitants.",
"title": "History"
},
{
"paragraph_id": 5,
"text": "In 1536, a large part of the city was destroyed by the great fire of Delft.",
"title": "History"
},
{
"paragraph_id": 6,
"text": "The town's association with the House of Orange started when William of Orange (Willem van Oranje), nicknamed William the Silent (Willem de Zwijger), took up residence in 1572 in the former Saint-Agatha convent (subsequently called the Prinsenhof). At the time he was the leader of growing national Dutch resistance against Spanish occupation, known as the Eighty Years' War. By then Delft was one of the leading cities of Holland and was equipped with the necessary city walls to serve as a headquarters. In October 1573, an attack by Spanish forces was repelled in the Battle of Delft.",
"title": "History"
},
{
"paragraph_id": 7,
"text": "After the Act of Abjuration was proclaimed in 1581, Delft became the de facto capital of the newly independent Netherlands, as the seat of the Prince of Orange.",
"title": "History"
},
{
"paragraph_id": 8,
"text": "When William was shot dead on 10 July 1584 by Balthazar Gerards in the hall of the Prinsenhof (now the Prinsenhof Museum), the family's traditional burial place in Breda was still in the hands of the Spanish. Therefore, he was buried in the Delft Nieuwe Kerk (New Church), starting a tradition for the House of Orange that has continued to the present day.",
"title": "History"
},
{
"paragraph_id": 9,
"text": "Around this time, Delft also occupied a prominent position in the field of printing.",
"title": "History"
},
{
"paragraph_id": 10,
"text": "A number of Italian glazed earthenware makers settled in the city and introduced a new style. The tapestry industry also flourished when famous manufacturer François Spierincx moved to the city. In the 17th century, Delft experienced a new heyday, thanks to the presence of an office of the Dutch East India Company (VOC) (opened in 1602) and the manufacture of Delft Blue china.",
"title": "History"
},
{
"paragraph_id": 11,
"text": "A number of notable artists based themselves in the city, including Leonard Bramer, Carel Fabritius, Pieter de Hoogh, Gerard Houckgeest, Emanuel de Witte, Jan Steen, and Johannes Vermeer. Reinier de Graaf and Antonie van Leeuwenhoek received international attention for their scientific research.",
"title": "History"
},
{
"paragraph_id": 12,
"text": "The Delft Explosion, also known in history as the Delft Thunderclap, occurred on 12 October 1654 when a gunpowder store exploded, destroying much of the city. Over a hundred people were killed and thousands were injured.",
"title": "History"
},
{
"paragraph_id": 13,
"text": "About 30 t (29.5 long tons; 33.1 short tons) of gunpowder were stored in barrels in a magazine in a former Clarist convent in the Doelenkwartier district, where the Paardenmarkt is now located. Cornelis Soetens, the keeper of the magazine, opened the store to check a sample of the powder and a huge explosion followed. Luckily, many citizens were away, visiting a market in Schiedam or a fair in The Hague.",
"title": "History"
},
{
"paragraph_id": 14,
"text": "Today, the explosion is primarily remembered for killing Rembrandt's most promising pupil, Carel Fabritius, and destroying almost all of his works.",
"title": "History"
},
{
"paragraph_id": 15,
"text": "Delft artist Egbert van der Poel painted several pictures of Delft showing the devastation.",
"title": "History"
},
{
"paragraph_id": 16,
"text": "The gunpowder store (Dutch: Kruithuis) was subsequently re-housed, a 'cannonball's distance away', outside the city, in a new building designed by architect Pieter Post.",
"title": "History"
},
{
"paragraph_id": 17,
"text": "The city centre retains a large number of monumental buildings, while in many streets there are canals of which the banks are connected by typical bridges, altogether making this city a notable tourist destination.",
"title": "Sights"
},
{
"paragraph_id": 18,
"text": "Historical buildings and other sights of interest include:",
"title": "Sights"
},
{
"paragraph_id": 19,
"text": "Delft is well known for the Delft pottery ceramic products which were styled on the imported Chinese porcelain of the 17th century. The city had an early start in this area since it was a home port of the Dutch East India Company. It can still be seen at the pottery factories De Koninklijke Porceleyne Fles (or Royal Delft) and De Delftse Pauw, while new ceramics and ceramic art can be found at the Gallery Terra Delft.",
"title": "Culture"
},
{
"paragraph_id": 20,
"text": "The painter Johannes Vermeer (1632–1675) was born in Delft. Vermeer used Delft streets and home interiors as the subject or background in his paintings. Several other famous painters lived and worked in Delft at that time, such as Pieter de Hoogh, Carel Fabritius, Nicolaes Maes, Gerard Houckgeest and Hendrick Cornelisz. van Vliet. They were all members of the Delft School. The Delft School is known for its images of domestic life and views of households, church interiors, courtyards, squares and the streets of Delft. The painters also produced pictures showing historic events, flowers, portraits for patrons and the court as well as decorative pieces of art.",
"title": "Culture"
},
{
"paragraph_id": 21,
"text": "Delft supports creative arts' companies. From 2001 the Bacinol [nl], a building that had been disused since 1951, began to house small companies in the creative arts sector. Its demolition started in December 2009, making way for the new railway tunnel in Delft. The occupants of the building, as well as the name 'Bacinol', moved to another building in the city. The name Bacinol relates to Dutch penicillin research during WWII.",
"title": "Culture"
},
{
"paragraph_id": 22,
"text": "Delft University of Technology (TU Delft) is one of four universities of technology in the Netherlands. It was founded as an academy for civil engineering in 1842 by King William II. Today, well over 21,000 students are enrolled.",
"title": "Education"
},
{
"paragraph_id": 23,
"text": "The UNESCO-IHE Institute for Water Education, providing postgraduate education for people from developing countries, draws on the strong tradition in water management and hydraulic engineering of the Delft university.",
"title": "Education"
},
{
"paragraph_id": 24,
"text": "The Hague University of Applied Sciences has a building on the Delft University of Technology campus. It opened in 2009 and offers several bachelor degrees for the Faculty of Technology, Innovation & Society.",
"title": "Education"
},
{
"paragraph_id": 25,
"text": "Inholland University of Applied Sciences also has a building on the Delft University of Technology campus. Several bachelor degrees for the Agri, Food & Life Sciences faculty and the Engineering, Design and Computing faculty are being taught at the Delft campus.",
"title": "Education"
},
{
"paragraph_id": 26,
"text": "In the local economic field, essential elements are:",
"title": "Economy"
},
{
"paragraph_id": 27,
"text": "East of Delft lies a relatively large nature and recreation area called the \"Delftse Hout\" (\"Delft Wood\"). Through the forest lie bike, horse-riding and footpaths. It also includes a vast lake (suitable for swimming and windsurfing), narrow beaches, a restaurant, and community gardens, plus camping ground and other recreational and sports facilities. (There is also a facility for renting bikes from the station.)",
"title": "Nature and recreation"
},
{
"paragraph_id": 28,
"text": "Inside the city, apart from a central park, there are several smaller town parks, including \"Nieuwe Plantage\", \"Agnetapark\", \"Kalverbos\". There is also the Botanical Garden of the TU and an arboretum in Delftse Hout.",
"title": "Nature and recreation"
},
{
"paragraph_id": 29,
"text": "Delft is the birthplace of:",
"title": "Notable people"
},
{
"paragraph_id": 30,
"text": "Delft is twinned with:",
"title": "International relations"
},
{
"paragraph_id": 31,
"text": "Trains stopping at these stations connect Delft with, among others, the nearby cities of Rotterdam and The Hague, as often as every five minutes, for most of the day.",
"title": "Transport"
},
{
"paragraph_id": 32,
"text": "There are several bus routes from Delft to similar destinations. Trams frequently travel between Delft and The Hague via special double tracks crossing the city.",
"title": "Transport"
},
{
"paragraph_id": 33,
"text": "The whole city center and adjacent areas are a paid on-street parking area. In 2018, with the day parking fee of 29.5 Euro, it was the most expensive on-street parking area in the Netherlands, with the city centers of Deventer and Dordrecht being second and third, respectively.",
"title": "Transport"
}
] | Delft is a city and municipality in the province of South Holland, Netherlands. It is located between Rotterdam, to the southeast, and The Hague, to the northwest. Together with them, it is a part of both the Rotterdam–The Hague metropolitan area and the Randstad. Delft is a popular tourist destination in the Netherlands, famous for its historical connections with the reigning House of Orange-Nassau, for its blue pottery, for being home to the painter Jan Vermeer, and for hosting Delft University of Technology. Historically, Delft played a highly influential role in the Dutch Golden Age. In terms of science and technology, thanks to the pioneering contributions of Antonie van Leeuwenhoek and Martinus Beijerinck, Delft can be considered to be the birthplace of microbiology. | 2001-10-24T22:42:22Z | 2023-10-19T15:39:45Z | [
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] | https://en.wikipedia.org/wiki/Delft |
8,309 | Duesberg hypothesis | The Duesberg hypothesis is the claim that AIDS is not caused by HIV, but instead that AIDS is caused by noninfectious factors such as recreational and pharmaceutical drug use and that HIV is merely a harmless passenger virus. The hypothesis was popularized by University of California, Berkeley professor Peter Duesberg, from whom the hypothesis gets its name. The scientific consensus is that the Duesberg hypothesis is incorrect and that HIV is the cause of AIDS. The most prominent supporters of the hypothesis are Duesberg himself, biochemist and vitamin proponent David Rasnick, and journalist Celia Farber. The scientific community generally contends that Duesberg's arguments in favor of the hypothesis are the result of cherry-picking predominantly outdated scientific data and selectively ignoring evidence that demonstrates HIV's role in causing AIDS.
Duesberg argues that there is a statistical correlation between trends in recreational drug use and trends in AIDS cases. He argues that the epidemic of AIDS cases in the 1980s corresponds to a supposed epidemic of recreational drug use in the United States and Europe during the same time frame.
These claims are not supported by epidemiologic data. The average yearly increase in opioid-related deaths from 1990 to 2002 was nearly three times the yearly increase from 1979 to 1990, with the greatest increase in 2000–02, yet AIDS cases and deaths fell dramatically during the mid-to-late-1990s. Duesberg's claim that recreational drug use, rather than HIV, was the cause of AIDS has been specifically examined and found to be false. Cohort studies have found that only HIV-positive drug users develop opportunistic infections; HIV-negative drug users do not develop such infections, indicating that HIV rather than drug use is the cause of AIDS.
Duesberg has also argued that nitrite inhalants were the cause of the epidemic of Kaposi sarcoma (KS) in gay men. However, this argument has been described as an example of the fallacy of a statistical confounding effect; it is now known that a herpesvirus, potentiated by HIV, is responsible for AIDS-associated KS.
Moreover, in addition to recreational drugs, Duesberg argues that anti-HIV drugs such as zidovudine (AZT) can cause AIDS. Duesberg's claim that antiviral medication causes AIDS is regarded as disproven by the scientific community. Placebo-controlled studies have found that AZT as a single agent produces modest and short-lived improvements in survival and delays the development of opportunistic infections; it certainly did not cause AIDS, which develops in both treated and untreated study patients. With the subsequent development of protease inhibitors and highly active antiretroviral therapy, numerous studies have documented the fact that anti-HIV drugs prevent the development of AIDS and substantially prolong survival, further disproving the claim that these drugs "cause" AIDS.
Several studies have specifically addressed Duesberg's claim that recreational drug abuse or sexual promiscuity were responsible for the manifestations of AIDS. An early study of his claims, published in Nature in 1993, found Duesberg's drug abuse-AIDS hypothesis to have "no basis in fact."
A large prospective study followed a group of 715 homosexual men in the Vancouver, Canada, area; approximately half were HIV-seropositive or became so during the follow-up period, and the remainder were HIV-seronegative. After more than 8 years of follow-up, despite similar rates of drug use, sexual contact, and other supposed risk factors in both groups, only the HIV-positive group suffered from opportunistic infections. Similarly, CD4 counts dropped in the patients who were HIV-infected, but remained stable in the HIV-negative patients, despite similar rates of risk behavior. The authors concluded that "the risk-AIDS hypothesis ... is clearly rejected by our data," and that "the evidence supports the hypothesis that HIV-1 has an integral role in the CD4 depletion and progressive immune dysfunction that characterise AIDS."
Similarly, the Multicenter AIDS Cohort Study (MACS) and the Women's Interagency HIV Study (WIHS)—which between them observed more than 8,000 Americans—demonstrated that "the presence of HIV infection is the only factor that is strongly and consistently associated with the conditions that define AIDS." A 2008 study found that recreational drug use (including cannabis, cocaine, poppers, and amphetamines) had no effect on CD4 or CD8 T-cell counts, providing further evidence against a role of recreational drugs as a cause of AIDS.
Duesberg argued in 1989 that a significant number of AIDS victims had died without proof of HIV infection. However, with the use of modern culture techniques and polymerase chain reaction testing, HIV can be demonstrated in virtually all patients with AIDS. Since AIDS is now defined partially by the presence of HIV, Duesberg claims it is impossible by definition to offer evidence that AIDS doesn't require HIV. However, the first definitions of AIDS mentioned no cause and the first AIDS diagnoses were made before HIV was discovered. The addition of HIV positivity to surveillance criteria as an absolutely necessary condition for case reporting occurred only in 1993, after a scientific consensus was established that HIV caused AIDS.
According to the Duesberg hypothesis, AIDS is not found in Africa. What Duesberg calls "the myth of an African AIDS epidemic," among people" exists for several reasons, including:
Duesberg states that African AIDS cases are "a collection of long-established, indigenous diseases, such as chronic fevers, weight loss, alias "slim disease," diarrhea, and tuberculosis" that result from malnutrition and poor sanitation. African AIDS cases, though, have increased in the last three decades as HIV's prevalence has increased but as malnutrition percentages and poor sanitation have declined in many African regions. In addition, while HIV and AIDS are more prevalent in urban than in rural settings in Africa, malnutrition and poor sanitation are found more commonly in rural than in urban settings.
According to Duesberg, common diseases are easily misdiagnosed as AIDS in Africa because "the diagnosis of African AIDS is arbitrary" and does not include HIV testing. A definition of AIDS agreed upon in 1985 by the World Health Organization in Bangui did not require a positive HIV test, but since 1985, many African countries have added positive HIV tests to the Bangui criteria for AIDS or changed their definitions to match those of the U.S. Centers for Disease Control. One of the reasons for using more HIV tests despite their expense is that, rather than overestimating AIDS as Duesberg suggests, the Bangui definition alone excluded nearly half of African AIDS patients."
Duesberg notes that diseases associated with AIDS differ between African and Western populations, concluding that the causes of immunodeficiency must be different. Tuberculosis is much more commonly diagnosed among AIDS patients in Africa than in Western countries, while PCP conforms to the opposite pattern. Tuberculosis, though, had higher prevalence in Africa than in the West before the spread of HIV. In Africa and the United States, HIV has spurred a similar percentage increase in tuberculosis cases. PCP may be underestimated in Africa: since machinery "required for accurate testing is relatively rare in many resource-poor areas, including large parts of Africa, PCP is likely to be underdiagnosed in Africa. Consistent with this hypothesis, studies that report the highest rates of PCP in Africa are those that use the most advanced diagnostic methods" Duesberg also claims that Kaposi's Sarcoma is "exclusively diagnosed in male homosexual risk groups using nitrite inhalants and other psychoactive drugs as aphrodisiacs", but the cancer is fairly common among heterosexuals in some parts of Africa, and is found in heterosexuals in the United States as well.
Because reported AIDS cases in Africa and other parts of the developing world include a larger proportion of people who do not belong to Duesberg's preferred risk groups of drug addicts and male homosexuals, Duesberg writes on his website that "There are no risk groups in Africa, like drug addicts and homosexuals." However, many studies have addressed the issue of risk groups in Africa and concluded that the risk of AIDS is not equally distributed. In addition, AIDS in Africa largely kills sexually active working-age adults.
South African president Thabo Mbeki accepted Duesberg's hypothesis and, through the mid-2000s, rejected offers of medical assistance to fight HIV infection, a policy of inaction that cost over 300,000 lives.
Duesberg argues that retroviruses like HIV must be harmless to survive: they do not kill cells and they do not cause cancer, he maintains. Duesberg writes, "retroviruses do not kill cells because they depend on viable cells for the replication of their RNA from viral DNA integrated into cellular DNA." Duesberg elsewhere states that "the typical virus reproduces by entering a living cell and commandeering the cell's resources in order to make new virus particles, a process that ends with the disintegration of the dead cell."
Duesberg also rejects the involvement of retroviruses and other viruses in cancer. To him, virus-associated cancers are "freak accidents of nature" that do not warrant research programs such as the war on cancer. Duesberg rejects a role in cancer for numerous viruses, including leukemia viruses, Epstein–Barr virus, human papilloma virus, hepatitis B, feline leukemia virus, and human T-lymphotropic virus.
Duesberg claims that the supposedly innocuous nature of all retroviruses is supported by what he considers to be their normal mode of proliferation: infection from mother to child in utero. Duesberg does not suggest that HIV is an endogenous retrovirus, a virus integrated into the germline and genetically heritable:
...[a mother] provides her child with a nine-month continuous exposure to her blood and therefore has at least a 50 percent chance of passing HIV to the baby.
The consensus in the scientific community is that the Duesberg hypothesis has been refuted by a large and growing mass of evidence showing that HIV causes AIDS, that the amount of virus in the blood correlates with disease progression, that a plausible mechanism for HIV's action has been proposed, and that anti-HIV medication decreases mortality and opportunistic infection in people with AIDS.
In the 9 December 1994 issue of Science (Vol. 266, No. 5191), Duesberg's methods and claims were evaluated in a group of articles. The authors concluded that
The vast majority of people with AIDS have never received antiretroviral drugs, including those in developed countries prior to the licensure of AZT (zidovudine) in 1987, and people in developing countries today where very few individuals have access to these medications.
The NIAID reports that
in the mid-1980s, clinical trials enrolling patients with AIDS found that AZT given as single-drug therapy conferred a modest survival advantage compared [with] placebo. Among HIV-infected patients who had not yet developed AIDS, placebo-controlled trials found that AZT given as single-drug therapy delayed, for a year or two, the onset of AIDS-related illnesses. Significantly, long-term follow-up of these trials did not show a prolonged benefit of AZT, but also did not indicate that the drug increased disease progression or mortality. The lack of excess AIDS cases and death in the AZT arms of these placebo-controlled trials in effect counters the argument that AZT causes AIDS. Subsequent clinical trials found that patients receiving two-drug combinations had up to 50 percent improvements in time to progression to AIDS and in survival when compared with people receiving single-drug therapy. In more recent years, three-drug combination therapies have produced another 50 to 80 percent improvement in progression to AIDS and in survival when compared with two-drug regimens in clinical trials.
Use of potent anti-HIV combination therapies has contributed to dramatic reductions in the incidence of AIDS and AIDS-related deaths in populations where these drugs are widely available, an effect which clearly would not be seen if antiretroviral drugs caused AIDS.
Duesberg claims as support for his idea that many drug-free HIV-positive people have not yet developed AIDS; HIV/AIDS scientists note that many drug-free HIV-positive people have developed AIDS, and that, in the absence of medical treatment or rare genetic factors postulated to delay disease progression, it is very likely that nearly all HIV-positive people will eventually develop AIDS. Scientists also note that HIV-negative drug users do not suffer from immune system collapse. | [
{
"paragraph_id": 0,
"text": "The Duesberg hypothesis is the claim that AIDS is not caused by HIV, but instead that AIDS is caused by noninfectious factors such as recreational and pharmaceutical drug use and that HIV is merely a harmless passenger virus. The hypothesis was popularized by University of California, Berkeley professor Peter Duesberg, from whom the hypothesis gets its name. The scientific consensus is that the Duesberg hypothesis is incorrect and that HIV is the cause of AIDS. The most prominent supporters of the hypothesis are Duesberg himself, biochemist and vitamin proponent David Rasnick, and journalist Celia Farber. The scientific community generally contends that Duesberg's arguments in favor of the hypothesis are the result of cherry-picking predominantly outdated scientific data and selectively ignoring evidence that demonstrates HIV's role in causing AIDS.",
"title": ""
},
{
"paragraph_id": 1,
"text": "Duesberg argues that there is a statistical correlation between trends in recreational drug use and trends in AIDS cases. He argues that the epidemic of AIDS cases in the 1980s corresponds to a supposed epidemic of recreational drug use in the United States and Europe during the same time frame.",
"title": "Role of legal and illegal drug use"
},
{
"paragraph_id": 2,
"text": "These claims are not supported by epidemiologic data. The average yearly increase in opioid-related deaths from 1990 to 2002 was nearly three times the yearly increase from 1979 to 1990, with the greatest increase in 2000–02, yet AIDS cases and deaths fell dramatically during the mid-to-late-1990s. Duesberg's claim that recreational drug use, rather than HIV, was the cause of AIDS has been specifically examined and found to be false. Cohort studies have found that only HIV-positive drug users develop opportunistic infections; HIV-negative drug users do not develop such infections, indicating that HIV rather than drug use is the cause of AIDS.",
"title": "Role of legal and illegal drug use"
},
{
"paragraph_id": 3,
"text": "Duesberg has also argued that nitrite inhalants were the cause of the epidemic of Kaposi sarcoma (KS) in gay men. However, this argument has been described as an example of the fallacy of a statistical confounding effect; it is now known that a herpesvirus, potentiated by HIV, is responsible for AIDS-associated KS.",
"title": "Role of legal and illegal drug use"
},
{
"paragraph_id": 4,
"text": "Moreover, in addition to recreational drugs, Duesberg argues that anti-HIV drugs such as zidovudine (AZT) can cause AIDS. Duesberg's claim that antiviral medication causes AIDS is regarded as disproven by the scientific community. Placebo-controlled studies have found that AZT as a single agent produces modest and short-lived improvements in survival and delays the development of opportunistic infections; it certainly did not cause AIDS, which develops in both treated and untreated study patients. With the subsequent development of protease inhibitors and highly active antiretroviral therapy, numerous studies have documented the fact that anti-HIV drugs prevent the development of AIDS and substantially prolong survival, further disproving the claim that these drugs \"cause\" AIDS.",
"title": "Role of legal and illegal drug use"
},
{
"paragraph_id": 5,
"text": "Several studies have specifically addressed Duesberg's claim that recreational drug abuse or sexual promiscuity were responsible for the manifestations of AIDS. An early study of his claims, published in Nature in 1993, found Duesberg's drug abuse-AIDS hypothesis to have \"no basis in fact.\"",
"title": "Role of legal and illegal drug use"
},
{
"paragraph_id": 6,
"text": "A large prospective study followed a group of 715 homosexual men in the Vancouver, Canada, area; approximately half were HIV-seropositive or became so during the follow-up period, and the remainder were HIV-seronegative. After more than 8 years of follow-up, despite similar rates of drug use, sexual contact, and other supposed risk factors in both groups, only the HIV-positive group suffered from opportunistic infections. Similarly, CD4 counts dropped in the patients who were HIV-infected, but remained stable in the HIV-negative patients, despite similar rates of risk behavior. The authors concluded that \"the risk-AIDS hypothesis ... is clearly rejected by our data,\" and that \"the evidence supports the hypothesis that HIV-1 has an integral role in the CD4 depletion and progressive immune dysfunction that characterise AIDS.\"",
"title": "Role of legal and illegal drug use"
},
{
"paragraph_id": 7,
"text": "Similarly, the Multicenter AIDS Cohort Study (MACS) and the Women's Interagency HIV Study (WIHS)—which between them observed more than 8,000 Americans—demonstrated that \"the presence of HIV infection is the only factor that is strongly and consistently associated with the conditions that define AIDS.\" A 2008 study found that recreational drug use (including cannabis, cocaine, poppers, and amphetamines) had no effect on CD4 or CD8 T-cell counts, providing further evidence against a role of recreational drugs as a cause of AIDS.",
"title": "Role of legal and illegal drug use"
},
{
"paragraph_id": 8,
"text": "Duesberg argued in 1989 that a significant number of AIDS victims had died without proof of HIV infection. However, with the use of modern culture techniques and polymerase chain reaction testing, HIV can be demonstrated in virtually all patients with AIDS. Since AIDS is now defined partially by the presence of HIV, Duesberg claims it is impossible by definition to offer evidence that AIDS doesn't require HIV. However, the first definitions of AIDS mentioned no cause and the first AIDS diagnoses were made before HIV was discovered. The addition of HIV positivity to surveillance criteria as an absolutely necessary condition for case reporting occurred only in 1993, after a scientific consensus was established that HIV caused AIDS.",
"title": "Current AIDS definitions"
},
{
"paragraph_id": 9,
"text": "According to the Duesberg hypothesis, AIDS is not found in Africa. What Duesberg calls \"the myth of an African AIDS epidemic,\" among people\" exists for several reasons, including:",
"title": "AIDS in Africa"
},
{
"paragraph_id": 10,
"text": "Duesberg states that African AIDS cases are \"a collection of long-established, indigenous diseases, such as chronic fevers, weight loss, alias \"slim disease,\" diarrhea, and tuberculosis\" that result from malnutrition and poor sanitation. African AIDS cases, though, have increased in the last three decades as HIV's prevalence has increased but as malnutrition percentages and poor sanitation have declined in many African regions. In addition, while HIV and AIDS are more prevalent in urban than in rural settings in Africa, malnutrition and poor sanitation are found more commonly in rural than in urban settings.",
"title": "AIDS in Africa"
},
{
"paragraph_id": 11,
"text": "According to Duesberg, common diseases are easily misdiagnosed as AIDS in Africa because \"the diagnosis of African AIDS is arbitrary\" and does not include HIV testing. A definition of AIDS agreed upon in 1985 by the World Health Organization in Bangui did not require a positive HIV test, but since 1985, many African countries have added positive HIV tests to the Bangui criteria for AIDS or changed their definitions to match those of the U.S. Centers for Disease Control. One of the reasons for using more HIV tests despite their expense is that, rather than overestimating AIDS as Duesberg suggests, the Bangui definition alone excluded nearly half of African AIDS patients.\"",
"title": "AIDS in Africa"
},
{
"paragraph_id": 12,
"text": "Duesberg notes that diseases associated with AIDS differ between African and Western populations, concluding that the causes of immunodeficiency must be different. Tuberculosis is much more commonly diagnosed among AIDS patients in Africa than in Western countries, while PCP conforms to the opposite pattern. Tuberculosis, though, had higher prevalence in Africa than in the West before the spread of HIV. In Africa and the United States, HIV has spurred a similar percentage increase in tuberculosis cases. PCP may be underestimated in Africa: since machinery \"required for accurate testing is relatively rare in many resource-poor areas, including large parts of Africa, PCP is likely to be underdiagnosed in Africa. Consistent with this hypothesis, studies that report the highest rates of PCP in Africa are those that use the most advanced diagnostic methods\" Duesberg also claims that Kaposi's Sarcoma is \"exclusively diagnosed in male homosexual risk groups using nitrite inhalants and other psychoactive drugs as aphrodisiacs\", but the cancer is fairly common among heterosexuals in some parts of Africa, and is found in heterosexuals in the United States as well.",
"title": "AIDS in Africa"
},
{
"paragraph_id": 13,
"text": "Because reported AIDS cases in Africa and other parts of the developing world include a larger proportion of people who do not belong to Duesberg's preferred risk groups of drug addicts and male homosexuals, Duesberg writes on his website that \"There are no risk groups in Africa, like drug addicts and homosexuals.\" However, many studies have addressed the issue of risk groups in Africa and concluded that the risk of AIDS is not equally distributed. In addition, AIDS in Africa largely kills sexually active working-age adults.",
"title": "AIDS in Africa"
},
{
"paragraph_id": 14,
"text": "South African president Thabo Mbeki accepted Duesberg's hypothesis and, through the mid-2000s, rejected offers of medical assistance to fight HIV infection, a policy of inaction that cost over 300,000 lives.",
"title": "AIDS in Africa"
},
{
"paragraph_id": 15,
"text": "Duesberg argues that retroviruses like HIV must be harmless to survive: they do not kill cells and they do not cause cancer, he maintains. Duesberg writes, \"retroviruses do not kill cells because they depend on viable cells for the replication of their RNA from viral DNA integrated into cellular DNA.\" Duesberg elsewhere states that \"the typical virus reproduces by entering a living cell and commandeering the cell's resources in order to make new virus particles, a process that ends with the disintegration of the dead cell.\"",
"title": "Duesberg claims that retroviruses like HIV must be harmless to survive"
},
{
"paragraph_id": 16,
"text": "Duesberg also rejects the involvement of retroviruses and other viruses in cancer. To him, virus-associated cancers are \"freak accidents of nature\" that do not warrant research programs such as the war on cancer. Duesberg rejects a role in cancer for numerous viruses, including leukemia viruses, Epstein–Barr virus, human papilloma virus, hepatitis B, feline leukemia virus, and human T-lymphotropic virus.",
"title": "Duesberg claims that retroviruses like HIV must be harmless to survive"
},
{
"paragraph_id": 17,
"text": "Duesberg claims that the supposedly innocuous nature of all retroviruses is supported by what he considers to be their normal mode of proliferation: infection from mother to child in utero. Duesberg does not suggest that HIV is an endogenous retrovirus, a virus integrated into the germline and genetically heritable:",
"title": "Duesberg claims that retroviruses like HIV must be harmless to survive"
},
{
"paragraph_id": 18,
"text": "...[a mother] provides her child with a nine-month continuous exposure to her blood and therefore has at least a 50 percent chance of passing HIV to the baby.",
"title": "Duesberg claims that retroviruses like HIV must be harmless to survive"
},
{
"paragraph_id": 19,
"text": "The consensus in the scientific community is that the Duesberg hypothesis has been refuted by a large and growing mass of evidence showing that HIV causes AIDS, that the amount of virus in the blood correlates with disease progression, that a plausible mechanism for HIV's action has been proposed, and that anti-HIV medication decreases mortality and opportunistic infection in people with AIDS.",
"title": "Scientific response to the Duesberg hypothesis"
},
{
"paragraph_id": 20,
"text": "In the 9 December 1994 issue of Science (Vol. 266, No. 5191), Duesberg's methods and claims were evaluated in a group of articles. The authors concluded that",
"title": "Scientific response to the Duesberg hypothesis"
},
{
"paragraph_id": 21,
"text": "The vast majority of people with AIDS have never received antiretroviral drugs, including those in developed countries prior to the licensure of AZT (zidovudine) in 1987, and people in developing countries today where very few individuals have access to these medications.",
"title": "Scientific response to the Duesberg hypothesis"
},
{
"paragraph_id": 22,
"text": "The NIAID reports that",
"title": "Scientific response to the Duesberg hypothesis"
},
{
"paragraph_id": 23,
"text": "in the mid-1980s, clinical trials enrolling patients with AIDS found that AZT given as single-drug therapy conferred a modest survival advantage compared [with] placebo. Among HIV-infected patients who had not yet developed AIDS, placebo-controlled trials found that AZT given as single-drug therapy delayed, for a year or two, the onset of AIDS-related illnesses. Significantly, long-term follow-up of these trials did not show a prolonged benefit of AZT, but also did not indicate that the drug increased disease progression or mortality. The lack of excess AIDS cases and death in the AZT arms of these placebo-controlled trials in effect counters the argument that AZT causes AIDS. Subsequent clinical trials found that patients receiving two-drug combinations had up to 50 percent improvements in time to progression to AIDS and in survival when compared with people receiving single-drug therapy. In more recent years, three-drug combination therapies have produced another 50 to 80 percent improvement in progression to AIDS and in survival when compared with two-drug regimens in clinical trials.",
"title": "Scientific response to the Duesberg hypothesis"
},
{
"paragraph_id": 24,
"text": "Use of potent anti-HIV combination therapies has contributed to dramatic reductions in the incidence of AIDS and AIDS-related deaths in populations where these drugs are widely available, an effect which clearly would not be seen if antiretroviral drugs caused AIDS.",
"title": "Scientific response to the Duesberg hypothesis"
},
{
"paragraph_id": 25,
"text": "Duesberg claims as support for his idea that many drug-free HIV-positive people have not yet developed AIDS; HIV/AIDS scientists note that many drug-free HIV-positive people have developed AIDS, and that, in the absence of medical treatment or rare genetic factors postulated to delay disease progression, it is very likely that nearly all HIV-positive people will eventually develop AIDS. Scientists also note that HIV-negative drug users do not suffer from immune system collapse.",
"title": "Scientific response to the Duesberg hypothesis"
}
] | The Duesberg hypothesis is the claim that AIDS is not caused by HIV, but instead that AIDS is caused by noninfectious factors such as recreational and pharmaceutical drug use and that HIV is merely a harmless passenger virus. The hypothesis was popularized by University of California, Berkeley professor Peter Duesberg, from whom the hypothesis gets its name. The scientific consensus is that the Duesberg hypothesis is incorrect and that HIV is the cause of AIDS. The most prominent supporters of the hypothesis are Duesberg himself, biochemist and vitamin proponent David Rasnick, and journalist Celia Farber. The scientific community generally contends that Duesberg's arguments in favor of the hypothesis are the result of cherry-picking predominantly outdated scientific data and selectively ignoring evidence that demonstrates HIV's role in causing AIDS. | 2001-08-12T07:09:12Z | 2023-12-16T00:23:07Z | [
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8,310 | DSL (disambiguation) | DSL or digital subscriber line is a family of technologies that provide digital data transmission over the wires of a local telephone network.
DSL may also refer to: | [
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] | DSL or digital subscriber line is a family of technologies that provide digital data transmission over the wires of a local telephone network. DSL may also refer to: Damn Small Linux, a very small Linux distribution
Danish Sign Language
Data Security Law of the People's Republic of China
Definitive software library
Design Science License, a copyleft license for intellectual property
Diagnostic Systems Laboratories, a company now part of Beckman-Coulter
Dictionary of the Scots Language
Doctor of Strategic Leadership
Domain-specific language, a specialized computer language
Digital subscriber line, a device used to connect a computer or router to a telephone line
Dominican Summer League of baseball
DSL, a musical artist signed to Ed Banger Records
Deutsche Schule Lagos, or the German School Lagos
"Don't Say Love", a 2023 song by Leigh-Anne | 2001-10-16T16:38:47Z | 2023-07-29T19:09:51Z | [
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8,311 | Dinosaur | Dinosaurs are a diverse group of reptiles of the clade Dinosauria. They first appeared during the Triassic period, between 243 and 233.23 million years ago (mya), although the exact origin and timing of the evolution of dinosaurs is a subject of active research. They became the dominant terrestrial vertebrates after the Triassic–Jurassic extinction event 201.3 mya and their dominance continued throughout the Jurassic and Cretaceous periods. The fossil record shows that birds are feathered dinosaurs, having evolved from earlier theropods during the Late Jurassic epoch, and are the only dinosaur lineage known to have survived the Cretaceous–Paleogene extinction event approximately 66 mya. Dinosaurs can therefore be divided into avian dinosaurs—birds—and the extinct non-avian dinosaurs, which are all dinosaurs other than birds.
Dinosaurs are varied from taxonomic, morphological and ecological standpoints. Birds, at over 10,700 living species, are among the most diverse groups of vertebrates. Using fossil evidence, paleontologists have identified over 900 distinct genera and more than 1,000 different species of non-avian dinosaurs. Dinosaurs are represented on every continent by both extant species (birds) and fossil remains. Through the first half of the 20th century, before birds were recognized as dinosaurs, most of the scientific community believed dinosaurs to have been sluggish and cold-blooded. Most research conducted since the 1970s, however, has indicated that dinosaurs were active animals with elevated metabolisms and numerous adaptations for social interaction. Some were herbivorous, others carnivorous. Evidence suggests that all dinosaurs were egg-laying, and that nest-building was a trait shared by many dinosaurs, both avian and non-avian.
While dinosaurs were ancestrally bipedal, many extinct groups included quadrupedal species, and some were able to shift between these stances. Elaborate display structures such as horns or crests are common to all dinosaur groups, and some extinct groups developed skeletal modifications such as bony armor and spines. While the dinosaurs' modern-day surviving avian lineage (birds) are generally small due to the constraints of flight, many prehistoric dinosaurs (non-avian and avian) were large-bodied—the largest sauropod dinosaurs are estimated to have reached lengths of 39.7 meters (130 feet) and heights of 18 m (59 ft) and were the largest land animals of all time. The misconception that non-avian dinosaurs were uniformly gigantic is based in part on preservation bias, as large, sturdy bones are more likely to last until they are fossilized. Many dinosaurs were quite small, some measuring about 50 centimeters (20 inches) in length.
The first dinosaur fossils were recognized in the early 19th century, with the name "dinosaur" (meaning "terrible lizard") being coined by Sir Richard Owen in 1842 to refer to these "great fossil lizards". Since then, mounted fossil dinosaur skeletons have been major attractions at museums worldwide, and dinosaurs have become an enduring part of popular culture. The large sizes of some dinosaurs, as well as their seemingly monstrous and fantastic nature, have ensured their regular appearance in best-selling books and films, such as Jurassic Park. Persistent public enthusiasm for the animals has resulted in significant funding for dinosaur science, and new discoveries are regularly covered by the media.
Under phylogenetic nomenclature, dinosaurs are usually defined as the group consisting of the most recent common ancestor (MRCA) of Triceratops and modern birds (Neornithes), and all its descendants. It has also been suggested that Dinosauria be defined with respect to the MRCA of Megalosaurus and Iguanodon, because these were two of the three genera cited by Richard Owen when he recognized the Dinosauria. Both definitions result in the same set of animals being defined as dinosaurs: "Dinosauria = Ornithischia + Saurischia". This definition includes major groups such as ankylosaurians (armored herbivorous quadrupeds), stegosaurians (plated herbivorous quadrupeds), ceratopsians (bipedal or quadrupedal herbivores with neck frills), pachycephalosaurians (bipedal herbivores with thick skulls), ornithopods (bipedal or quadrupedal herbivores including "duck-bills"), theropods (mostly bipedal carnivores and birds), and sauropodomorphs (mostly large herbivorous quadrupeds with long necks and tails).
Birds are the sole surviving dinosaurs. In traditional taxonomy, birds were considered a separate class that had evolved from dinosaurs, a distinct superorder. However, a majority of contemporary paleontologists concerned with dinosaurs reject the traditional style of classification in favor of phylogenetic taxonomy; this approach requires that, for a group to be natural, all descendants of members of the group must be included in the group. Birds belong to the dinosaur subgroup Maniraptora, which are coelurosaurs, which are theropods, which are saurischians.
Research by Matthew G. Baron, David B. Norman, and Paul M. Barrett in 2017 suggested a radical revision of dinosaurian systematics. Phylogenetic analysis by Baron et al. recovered the Ornithischia as being closer to the Theropoda than the Sauropodomorpha, as opposed to the traditional union of theropods with sauropodomorphs. This would cause sauropods and kin to fall outside traditional dinosaurs, so they re-defined Dinosauria as the last common ancestor of Triceratops horridus, Passer domesticus and Diplodocus carnegii, and all of its descendants, to ensure that sauropods and kin remain included as dinosaurs. They also resurrected the clade Ornithoscelida to refer to the group containing Ornithischia and Theropoda.
Using one of the above definitions, dinosaurs can be generally described as archosaurs with hind limbs held erect beneath the body. Other prehistoric animals, including pterosaurs, mosasaurs, ichthyosaurs, plesiosaurs, and Dimetrodon, while often popularly conceived of as dinosaurs, are not taxonomically classified as dinosaurs. Pterosaurs are distantly related to dinosaurs, being members of the clade Ornithodira. The other groups mentioned are, like dinosaurs and pterosaurs, members of Sauropsida (the reptile and bird clade), except Dimetrodon (which is a synapsid). None of them had the erect hind limb posture characteristic of true dinosaurs.
Dinosaurs were the dominant terrestrial vertebrates of the Mesozoic Era, especially the Jurassic and Cretaceous periods. Other groups of animals were restricted in size and niches; mammals, for example, rarely exceeded the size of a domestic cat, and were generally rodent-sized carnivores of small prey. They have always been recognized as an extremely varied group of animals; over 900 non-avian dinosaur genera have been identified with certainty as of 2018, and the total number of genera preserved in the fossil record has been estimated at around 1850, nearly 75% of which remain to be discovered, and 1124 species by 2016. A 1995 study predicted that about 3,400 dinosaur genera ever existed, including many that would not have been preserved in the fossil record.
In 2016, the estimated number of dinosaur species that existed in the Mesozoic was 1,543–2,468. In 2021, the number of modern-day birds (avian dinosaurs) was estimated to be at 10,806 species. Some are herbivorous, others carnivorous, including seed-eaters, fish-eaters, insectivores, and omnivores. While dinosaurs were ancestrally bipedal (as are all modern birds), some prehistoric species were quadrupeds, and others, such as Anchisaurus and Iguanodon, could walk just as easily on two or four legs. Cranial modifications like horns and crests are common dinosaurian traits, and some extinct species had bony armor. Although known for large size, many Mesozoic dinosaurs were human-sized or smaller, and modern birds are generally small in size. Dinosaurs today inhabit every continent, and fossils show that they had achieved global distribution by at least the Early Jurassic epoch. Modern birds inhabit most available habitats, from terrestrial to marine, and there is evidence that some non-avian dinosaurs (such as Microraptor) could fly or at least glide, and others, such as spinosaurids, had semiaquatic habits.
While recent discoveries have made it more difficult to present a universally agreed-upon list of their distinguishing features, nearly all dinosaurs discovered so far share certain modifications to the ancestral archosaurian skeleton, or are clearly descendants of older dinosaurs showing these modifications. Although some later groups of dinosaurs featured further modified versions of these traits, they are considered typical for Dinosauria; the earliest dinosaurs had them and passed them on to their descendants. Such modifications, originating in the most recent common ancestor of a certain taxonomic group, are called the synapomorphies of such a group.
A detailed assessment of archosaur interrelations by Sterling Nesbitt confirmed or found the following twelve unambiguous synapomorphies, some previously known:
Nesbitt found a number of further potential synapomorphies and discounted a number of synapomorphies previously suggested. Some of these are also present in silesaurids, which Nesbitt recovered as a sister group to Dinosauria, including a large anterior trochanter, metatarsals II and IV of subequal length, reduced contact between ischium and pubis, the presence of a cnemial crest on the tibia and of an ascending process on the astragalus, and many others.
A variety of other skeletal features are shared by dinosaurs. However, because they either are common to other groups of archosaurs or were not present in all early dinosaurs, these features are not considered to be synapomorphies. For example, as diapsids, dinosaurs ancestrally had two pairs of Infratemporal fenestrae (openings in the skull behind the eyes), and as members of the diapsid group Archosauria, had additional openings in the snout and lower jaw. Additionally, several characteristics once thought to be synapomorphies are now known to have appeared before dinosaurs, or were absent in the earliest dinosaurs and independently evolved by different dinosaur groups. These include an elongated scapula, or shoulder blade; a sacrum composed of three or more fused vertebrae (three are found in some other archosaurs, but only two are found in Herrerasaurus); and a perforate acetabulum, or hip socket, with a hole at the center of its inside surface (closed in Saturnalia tupiniquim, for example). Another difficulty of determining distinctly dinosaurian features is that early dinosaurs and other archosaurs from the Late Triassic epoch are often poorly known and were similar in many ways; these animals have sometimes been misidentified in the literature.
Dinosaurs stand with their hind limbs erect in a manner similar to most modern mammals, but distinct from most other reptiles, whose limbs sprawl out to either side. This posture is due to the development of a laterally facing recess in the pelvis (usually an open socket) and a corresponding inwardly facing distinct head on the femur. Their erect posture enabled early dinosaurs to breathe easily while moving, which likely permitted stamina and activity levels that surpassed those of "sprawling" reptiles. Erect limbs probably also helped support the evolution of large size by reducing bending stresses on limbs. Some non-dinosaurian archosaurs, including rauisuchians, also had erect limbs but achieved this by a "pillar-erect" configuration of the hip joint, where instead of having a projection from the femur insert on a socket on the hip, the upper pelvic bone was rotated to form an overhanging shelf.
Dinosaur fossils have been known for millennia, although their true nature was not recognized. The Chinese considered them to be dragon bones and documented them as such. For example, Huayang Guo Zhi (華陽國志), a gazetteer compiled by Chang Qu (常璩) during the Western Jin Dynasty (265–316), reported the discovery of dragon bones at Wucheng in Sichuan Province. Villagers in central China have long unearthed fossilized "dragon bones" for use in traditional medicines. In Europe, dinosaur fossils were generally believed to be the remains of giants and other biblical creatures.
Scholarly descriptions of what would now be recognized as dinosaur bones first appeared in the late 17th century in England. Part of a bone, now known to have been the femur of a Megalosaurus, was recovered from a limestone quarry at Cornwell near Chipping Norton, Oxfordshire, in 1676. The fragment was sent to Robert Plot, Professor of Chemistry at the University of Oxford and first curator of the Ashmolean Museum, who published a description in his The Natural History of Oxford-shire (1677). He correctly identified the bone as the lower extremity of the femur of a large animal, and recognized that it was too large to belong to any known species. He, therefore, concluded it to be the femur of a huge human, perhaps a Titan or another type of giant featured in legends. Edward Lhuyd, a friend of Sir Isaac Newton, published Lithophylacii Britannici ichnographia (1699), the first scientific treatment of what would now be recognized as a dinosaur when he described and named a sauropod tooth, "Rutellum impicatum", that had been found in Caswell, near Witney, Oxfordshire.
Between 1815 and 1824, the Rev William Buckland, the first Reader of Geology at the University of Oxford, collected more fossilized bones of Megalosaurus and became the first person to describe a non-avian dinosaur in a scientific journal. The second non-avian dinosaur genus to be identified, Iguanodon, was according to legend discovered in 1822 by Mary Ann Mantell – the wife of English geologist Gideon Mantell who in fact had required remains years earlier. Gideon Mantell recognized similarities between his fossils and the bones of modern iguanas. He published his findings in 1825.
The study of these "great fossil lizards" soon became of great interest to European and American scientists, and in 1842 the English paleontologist Sir Richard Owen coined the term "dinosaur", using it to refer to the "distinct tribe or sub-order of Saurian Reptiles" that were then being recognized in England and around the world. The term is derived from Ancient Greek δεινός (deinos) 'terrible, potent or fearfully great', and σαῦρος (sauros) 'lizard or reptile'. Though the taxonomic name has often been interpreted as a reference to dinosaurs' teeth, claws, and other fearsome characteristics, Owen intended it also to evoke their size and majesty. Owen recognized that the remains that had been found so far, Iguanodon, Megalosaurus and Hylaeosaurus, shared distinctive features, and so decided to present them as a distinct taxonomic group. As clarified by British geologist and historian Hugh Torrens, Owen had given a presentation about fossil reptiles to the British Association for the Advancement of Science in 1841, but reports of the time show that Owen did not mention the word "dinosaur", nor recognize dinosaurs as a distinct group of reptiles in his address. He introduced the Dinosauria only in the revised text version of his talk published in April of 1842. With the backing of Prince Albert, the husband of Queen Victoria, Owen established the Natural History Museum, London, to display the national collection of dinosaur fossils and other biological and geological exhibits.
In 1858, William Parker Foulke discovered the first known American dinosaur, in marl pits in the small town of Haddonfield, New Jersey. (Although fossils had been found before, their nature had not been correctly discerned.) The creature was named Hadrosaurus foulkii. It was an extremely important find: Hadrosaurus was one of the first nearly complete dinosaur skeletons found (the first was in 1834, in Maidstone, England), and it was clearly a bipedal creature. This was a revolutionary discovery as, until that point, most scientists had believed dinosaurs walked on four feet, like other lizards. Foulke's discoveries sparked a wave of interests in dinosaurs in the United States, known as dinosaur mania.
Dinosaur mania was exemplified by the fierce rivalry between Edward Drinker Cope and Othniel Charles Marsh, both of whom raced to be the first to find new dinosaurs in what came to be known as the Bone Wars. This fight between the two scientists lasted for over 30 years, ending in 1897 when Cope died after spending his entire fortune on the dinosaur hunt. Many valuable dinosaur specimens were damaged or destroyed due to the pair's rough methods: for example, their diggers often used dynamite to unearth bones. Modern paleontologists would find such methods crude and unacceptable, since blasting easily destroys fossil and stratigraphic evidence. Despite their unrefined methods, the contributions of Cope and Marsh to paleontology were vast: Marsh unearthed 86 new species of dinosaur and Cope discovered 56, a total of 142 new species. Cope's collection is now at the American Museum of Natural History in New York City, while Marsh's is at the Peabody Museum of Natural History at Yale University.
World War II caused a pause in palaeontological research; after the war, research attention was also diverted increasingly to fossil mammals rather than dinosaurs, which were seen as sluggish and cold-blooded. At the end of the 1960s, however, the field of dinosaur research experienced a surge in activity that remains ongoing. Several seminal studies led to this activity. First, John Ostrom discovered the bird-like dromaeosaurid theropod Deinonychus and described it in 1969. Its anatomy indicated that it was an active predator that was likely warm-blooded, in marked contrast to the then-prevailing image of dinosaurs. Concurrently, Robert T. Bakker published a series of studies that likewise argued for active lifestyles in dinosaurs based on anatomical and ecological evidence (see § Physiology), which were subsequently summarized in his 1986 book The Dinosaur Heresies.
New revelations were supported by an increase in dinosaur discoveries. Major new dinosaur discoveries have been made by paleontologists working in previously unexplored regions, including India, South America, Madagascar, Antarctica, and most significantly China. Across theropods, sauropodomorphs, and ornithischians, the number of named genera began to increase exponentially in the 1990s. As of 2008, over 30 new species of dinosaurs were named each year. At least sauropodomorphs experienced a further increase in the number of named species in the 2010s, with an average of 9.3 new species having been named each year between 2009 and 2020. As a consequence, more sauropodomorphs were named between 1990 and 2020 than in all previous years combined. These new localities also led to improvements in overall specimen quality, with new species being increasingly named not on scrappy fossils but on more complete skeletons, sometimes from multiple individuals. Better specimens also led to new species being invalidated less frequently. Asian localities have produced the most complete theropod specimens, while North American localities have produced the most complete sauropodomorph specimens.
Prior to the dinosaur renaissance, dinosaurs were mostly classified using the traditional rank-based system of Linnaean taxonomy. The renaissance was also accompanied by the increasingly widespread application of cladistics, a more objective method of classification based on ancestry and shared traits, which has proved tremendously useful in the study of dinosaur systematics and evolution. Cladistic analysis, among other techniques, helps to compensate for an often incomplete and fragmentary fossil record. Reference books summarizing the state of dinosaur research, such as David B. Weishampel and colleagues' The Dinosauria, made knowledge more accessible and spurred further interest in dinosaur research. The release of the first and second editions of The Dinosauria in 1990 and 2004, and of a review paper by Paul Sereno in 1998, were accompanied by increases in the number of published phylogenetic trees for dinosaurs.
Dinosaur fossils are not limited to bones, but also include imprints or mineralized remains of skin coverings, organs, and other tissues. Of these, skin coverings based on keratin proteins are most easily preserved because of their cross-linked, hydrophobic molecular structure. Fossils of keratin-based skin coverings or bony skin coverings are known from most major groups of dinosaurs. Dinosaur fossils with scaly skin impressions have been found since the 19th century. Samuel Beckles discovered a sauropod forelimb with preserved skin in 1852 that was incorrectly attributed to a crocodile; it was correctly attributed by Marsh in 1888 and subject to further study by Reginald Hooley in 1917. Among ornithischians, in 1884 Jacob Wortman found skin impressions on the first known specimen of Edmontosaurus annectens, which were largely destroyed during the specimen's excavation. Owen and Hooley subsequently described skin impressions of Hypsilophodon and Iguanodon in 1885 and 1917. Since then, scale impressions have been most frequently found among hadrosaurids, where the impressions are known from nearly the entire body across multiple specimens.
Starting from the 1990s, major discoveries of exceptionally preserved fossils in deposits known as conservation Lagerstätten contributed to research on dinosaur soft tissues. Chiefly among these were the rocks that produced the Jehol (Early Cretaceous) and Yanliao (Mid-to-Late Jurassic) biotas of northeastern China, from which hundreds of dinosaur specimens bearing impressions of feather-like structures (both closely related to birds and otherwise, see § Origin of birds) have been described by Xing Xu and colleagues. In living reptiles and mammals, pigment-storing cellular structures known as melanosomes are partially responsible for producing colouration. Both chemical traces of melanin and characteristically-shaped melanosomes have been reported from feathers and scales of Jehol and Yanliao dinosaurs, including both theropods and ornithischians. This has enabled multiple full-body reconstructions of dinosaur colouration, such as for Sinosauropteryx and Psittacosaurus by Jakob Vinther and colleagues, and similar techniques have also been extended to dinosaur fossils from other localities. (However, some researchers have also suggested that fossilized melanosomes represent bacterial remains.) Stomach contents in some Jehol and Yanliao dinosaurs closely related to birds have also provided indirect indications of diet and digestive system anatomy (e.g., crops). More concrete evidence of internal anatomy has been reported in Scipionyx from the Pietraroja Plattenkalk of Italy. It preserves portions of the intestines, colon, liver, muscles, and windpipe.
Concurrently, a line of work led by Mary Higby Schweitzer, Jack Horner, and colleagues reported various occurrences of preserved soft tissues and proteins within dinosaur bone fossils. Various mineralized structures that likely represented red blood cells and collagen fibres had been found by Schweitzer and others in tyrannosaurid bones as early as 1991. However, in 2005, Schweitzer and colleagues reported that a femur of Tyrannosaurus preserved soft, flexible tissue within, including blood vessels, bone matrix, and connective tissue (bone fibers) that had retained their microscopic structure. This discovery suggested that original soft tissues could be preserved over geological time, with multiple mechanisms having been proposed. Later, in 2009, Schweitzer and colleagues reported that a Brachylophosaurus femur preserved similar microstructures, and immunohistochemical techniques (based on antibody binding) demonstrated the presence of proteins such as collagen, elastin, and laminin. Both specimens yielded collagen protein sequences that were viable for molecular phylogenetic analyses, which grouped them with birds as would be expected. The extraction of fragmentary DNA has also been reported for both of these fossils, along with a specimen of Hypacrosaurus. In 2015, Sergio Bertazzo and colleagues reported the preservation of collagen fibres and red blood cells in eight Cretaceous dinosaur specimens that did not show any signs of exceptional preservation, indicating that soft tissue may be preserved more commonly than previously thought. Suggestions that these structures represent bacterial biofilms have been rejected, but cross-contamination remains a possibility that is difficult to detect.
Dinosaurs diverged from their archosaur ancestors during the Middle to Late Triassic epochs, roughly 20 million years after the devastating Permian–Triassic extinction event wiped out an estimated 96% of all marine species and 70% of terrestrial vertebrate species approximately 252 million years ago. The oldest dinosaur fossils known from substantial remains date to the Carnian epoch of the Triassic period and have been found primarily in the Ischigualasto and Santa Maria Formations of Argentina and Brazil, and the Pebbly Arkose Formation of Zimbabwe.
The Ischigualasto Formation (radiometrically dated at 231-230 million years old) has produced the early saurischian Eoraptor, originally considered a member of the Herrerasauridae but now considered to be an early sauropodomorph, along with the herrerasaurids Herrerasaurus and Sanjuansaurus, and the sauropodomorphs Chromogisaurus, Eodromaeus, and Panphagia. Eoraptor's likely resemblance to the common ancestor of all dinosaurs suggests that the first dinosaurs would have been small, bipedal predators. The Santa Maria Formation (radiometrically dated to be older, at 233.23 million years old) has produced the herrerasaurids Gnathovorax and Staurikosaurus, along with the sauropodomorphs Bagualosaurus, Buriolestes, Guaibasaurus, Macrocollum, Nhandumirim, Pampadromaeus, Saturnalia, and Unaysaurus. The Pebbly Arkose Formation, which is of uncertain age but was likely comparable to the other two, has produced the sauropodomorph Mbiresaurus, along with an unnamed herrerasaurid.
Less well-preserved remains of the sauropodomorphs Jaklapallisaurus and Nambalia, along with the early saurischian Alwalkeria, are known from the Upper Maleri and Lower Maleri Formations of India. The Carnian-aged Chañares Formation of Argentina preserves primitive, dinosaur-like ornithodirans such as Lagosuchus and Lagerpeton in Argentina, making it another important site for understanding dinosaur evolution. These ornithodirans support the model of early dinosaurs as small, bipedal predators. Dinosaurs may have appeared as early as the Anisian epoch of the Triassic, approximately 243 million years ago, which is the age of Nyasasaurus from the Manda Formation of Tanzania. However, its known fossils are too fragmentary to identify it as a dinosaur or only a close relative. The referral of the Manda Formation to the Anisian is also uncertain. Regardless, dinosaurs existed alongside non-dinosaurian ornithodirans for a period of time, with estimates ranging from 5–10 million years to 21 million years.
When dinosaurs appeared, they were not the dominant terrestrial animals. The terrestrial habitats were occupied by various types of archosauromorphs and therapsids, like cynodonts and rhynchosaurs. Their main competitors were the pseudosuchians, such as aetosaurs, ornithosuchids and rauisuchians, which were more successful than the dinosaurs. Most of these other animals became extinct in the Triassic, in one of two events. First, at about 215 million years ago, a variety of basal archosauromorphs, including the protorosaurs, became extinct. This was followed by the Triassic–Jurassic extinction event (about 201 million years ago), that saw the end of most of the other groups of early archosaurs, like aetosaurs, ornithosuchids, phytosaurs, and rauisuchians. Rhynchosaurs and dicynodonts survived (at least in some areas) at least as late as early –mid Norian and late Norian or earliest Rhaetian stages, respectively, and the exact date of their extinction is uncertain. These losses left behind a land fauna of crocodylomorphs, dinosaurs, mammals, pterosaurians, and turtles. The first few lines of early dinosaurs diversified through the Carnian and Norian stages of the Triassic, possibly by occupying the niches of the groups that became extinct. Also notably, there was a heightened rate of extinction during the Carnian pluvial event.
Dinosaur evolution after the Triassic followed changes in vegetation and the location of continents. In the Late Triassic and Early Jurassic, the continents were connected as the single landmass Pangaea, and there was a worldwide dinosaur fauna mostly composed of coelophysoid carnivores and early sauropodomorph herbivores. Gymnosperm plants (particularly conifers), a potential food source, radiated in the Late Triassic. Early sauropodomorphs did not have sophisticated mechanisms for processing food in the mouth, and so must have employed other means of breaking down food farther along the digestive tract. The general homogeneity of dinosaurian faunas continued into the Middle and Late Jurassic, where most localities had predators consisting of ceratosaurians, megalosauroids, and allosauroids, and herbivores consisting of stegosaurian ornithischians and large sauropods. Examples of this include the Morrison Formation of North America and Tendaguru Beds of Tanzania. Dinosaurs in China show some differences, with specialized metriacanthosaurid theropods and unusual, long-necked sauropods like Mamenchisaurus. Ankylosaurians and ornithopods were also becoming more common, but primitive sauropodomorphs had become extinct. Conifers and pteridophytes were the most common plants. Sauropods, like earlier sauropodomorphs, were not oral processors, but ornithischians were evolving various means of dealing with food in the mouth, including potential cheek-like organs to keep food in the mouth, and jaw motions to grind food. Another notable evolutionary event of the Jurassic was the appearance of true birds, descended from maniraptoran coelurosaurians.
By the Early Cretaceous and the ongoing breakup of Pangaea, dinosaurs were becoming strongly differentiated by landmass. The earliest part of this time saw the spread of ankylosaurians, iguanodontians, and brachiosaurids through Europe, North America, and northern Africa. These were later supplemented or replaced in Africa by large spinosaurid and carcharodontosaurid theropods, and rebbachisaurid and titanosaurian sauropods, also found in South America. In Asia, maniraptoran coelurosaurians like dromaeosaurids, troodontids, and oviraptorosaurians became the common theropods, and ankylosaurids and early ceratopsians like Psittacosaurus became important herbivores. Meanwhile, Australia was home to a fauna of basal ankylosaurians, hypsilophodonts, and iguanodontians. The stegosaurians appear to have gone extinct at some point in the late Early Cretaceous or early Late Cretaceous. A major change in the Early Cretaceous, which would be amplified in the Late Cretaceous, was the evolution of flowering plants. At the same time, several groups of dinosaurian herbivores evolved more sophisticated ways to orally process food. Ceratopsians developed a method of slicing with teeth stacked on each other in batteries, and iguanodontians refined a method of grinding with dental batteries, taken to its extreme in hadrosaurids. Some sauropods also evolved tooth batteries, best exemplified by the rebbachisaurid Nigersaurus.
There were three general dinosaur faunas in the Late Cretaceous. In the northern continents of North America and Asia, the major theropods were tyrannosaurids and various types of smaller maniraptoran theropods, with a predominantly ornithischian herbivore assemblage of hadrosaurids, ceratopsians, ankylosaurids, and pachycephalosaurians. In the southern continents that had made up the now-splitting supercontinent Gondwana, abelisaurids were the common theropods, and titanosaurian sauropods the common herbivores. Finally, in Europe, dromaeosaurids, rhabdodontid iguanodontians, nodosaurid ankylosaurians, and titanosaurian sauropods were prevalent. Flowering plants were greatly radiating, with the first grasses appearing by the end of the Cretaceous. Grinding hadrosaurids and shearing ceratopsians became very diverse across North America and Asia. Theropods were also radiating as herbivores or omnivores, with therizinosaurians and ornithomimosaurians becoming common.
The Cretaceous–Paleogene extinction event, which occurred approximately 66 million years ago at the end of the Cretaceous, caused the extinction of all dinosaur groups except for the neornithine birds. Some other diapsid groups, including crocodilians, dyrosaurs, sebecosuchians, turtles, lizards, snakes, sphenodontians, and choristoderans, also survived the event.
The surviving lineages of neornithine birds, including the ancestors of modern ratites, ducks and chickens, and a variety of waterbirds, diversified rapidly at the beginning of the Paleogene period, entering ecological niches left vacant by the extinction of Mesozoic dinosaur groups such as the arboreal enantiornithines, aquatic hesperornithines, and even the larger terrestrial theropods (in the form of Gastornis, eogruiids, bathornithids, ratites, geranoidids, mihirungs, and "terror birds"). It is often stated that mammals out-competed the neornithines for dominance of most terrestrial niches but many of these groups co-existed with rich mammalian faunas for most of the Cenozoic Era. Terror birds and bathornithids occupied carnivorous guilds alongside predatory mammals, and ratites are still fairly successful as mid-sized herbivores; eogruiids similarly lasted from the Eocene to Pliocene, becoming extinct only very recently after over 20 million years of co-existence with many mammal groups.
Dinosaurs belong to a group known as archosaurs, which also includes modern crocodilians. Within the archosaur group, dinosaurs are differentiated most noticeably by their gait. Dinosaur legs extend directly beneath the body, whereas the legs of lizards and crocodilians sprawl out to either side.
Collectively, dinosaurs as a clade are divided into two primary branches, Saurischia and Ornithischia. Saurischia includes those taxa sharing a more recent common ancestor with birds than with Ornithischia, while Ornithischia includes all taxa sharing a more recent common ancestor with Triceratops than with Saurischia. Anatomically, these two groups can be distinguished most noticeably by their pelvic structure. Early saurischians—"lizard-hipped", from the Greek sauros (σαῦρος) meaning "lizard" and ischion (ἰσχίον) meaning "hip joint"—retained the hip structure of their ancestors, with a pubis bone directed cranially, or forward. This basic form was modified by rotating the pubis backward to varying degrees in several groups (Herrerasaurus, therizinosauroids, dromaeosaurids, and birds). Saurischia includes the theropods (exclusively bipedal and with a wide variety of diets) and sauropodomorphs (long-necked herbivores which include advanced, quadrupedal groups).
By contrast, ornithischians—"bird-hipped", from the Greek ornitheios (ὀρνίθειος) meaning "of a bird" and ischion (ἰσχίον) meaning "hip joint"—had a pelvis that superficially resembled a bird's pelvis: the pubic bone was oriented caudally (rear-pointing). Unlike birds, the ornithischian pubis also usually had an additional forward-pointing process. Ornithischia includes a variety of species that were primarily herbivores.
Despite the terms "bird hip" (Ornithischia) and "lizard hip" (Saurischia), birds are not part of Ornithischia. Birds instead belong to Saurischia, the "lizard-hipped" dinosaurs—birds evolved from earlier dinosaurs with "lizard hips".
The following is a simplified classification of dinosaur groups based on their evolutionary relationships, and those of the main dinosaur groups Theropoda, Sauropodomorpha and Ornithischia, compiled by Justin Tweet. Further details and other hypotheses of classification may be found on individual articles.
Timeline of major dinosaur groups per Holtz (2007).
Knowledge about dinosaurs is derived from a variety of fossil and non-fossil records, including fossilized bones, feces, trackways, gastroliths, feathers, impressions of skin, internal organs and other soft tissues. Many fields of study contribute to our understanding of dinosaurs, including physics (especially biomechanics), chemistry, biology, and the Earth sciences (of which paleontology is a sub-discipline). Two topics of particular interest and study have been dinosaur size and behavior.
Current evidence suggests that dinosaur average size varied through the Triassic, Early Jurassic, Late Jurassic and Cretaceous. Predatory theropod dinosaurs, which occupied most terrestrial carnivore niches during the Mesozoic, most often fall into the 100 to 1000 kg (220 to 2200 lb) category when sorted by estimated weight into categories based on order of magnitude, whereas recent predatory carnivoran mammals peak in the 10 to 100 kg (22 to 220 lb) category. The mode of Mesozoic dinosaur body masses is between 1 and 10 metric tons (1.1 and 11.0 short tons). This contrasts sharply with the average size of Cenozoic mammals, estimated by the National Museum of Natural History as about 2 to 5 kg (4.4 to 11.0 lb).
The sauropods were the largest and heaviest dinosaurs. For much of the dinosaur era, the smallest sauropods were larger than anything else in their habitat, and the largest was an order of magnitude more massive than anything else that has since walked the Earth. Giant prehistoric mammals such as Paraceratherium (the largest land mammal ever) were dwarfed by the giant sauropods, and only modern whales approach or surpass them in size. There are several proposed advantages for the large size of sauropods, including protection from predation, reduction of energy use, and longevity, but it may be that the most important advantage was dietary. Large animals are more efficient at digestion than small animals, because food spends more time in their digestive systems. This also permits them to subsist on food with lower nutritive value than smaller animals. Sauropod remains are mostly found in rock formations interpreted as dry or seasonally dry, and the ability to eat large quantities of low-nutrient browse would have been advantageous in such environments.
Scientists will probably never be certain of the largest and smallest dinosaurs to have ever existed. This is because only a tiny percentage of animals were ever fossilized and most of these remain buried in the earth. Few of the specimens that are recovered are complete skeletons, and impressions of skin and other soft tissues are rare. Rebuilding a complete skeleton by comparing the size and morphology of bones to those of similar, better-known species is an inexact art, and reconstructing the muscles and other organs of the living animal is, at best, a process of educated guesswork.
The tallest and heaviest dinosaur known from good skeletons is Giraffatitan brancai (previously classified as a species of Brachiosaurus). Its remains were discovered in Tanzania between 1907 and 1912. Bones from several similar-sized individuals were incorporated into the skeleton now mounted and on display at the Museum für Naturkunde in Berlin; this mount is 12 meters (39 ft) tall and 21.8 to 22.5 meters (72 to 74 ft) long, and would have belonged to an animal that weighed between 30000 and 60000 kilograms (70000 and 130000 lb). The longest complete dinosaur is the 27 meters (89 ft) long Diplodocus, which was discovered in Wyoming in the United States and displayed in Pittsburgh's Carnegie Museum of Natural History in 1907. The longest dinosaur known from good fossil material is Patagotitan: the skeleton mount in the American Museum of Natural History in New York is 37 meters (121 ft) long. The Museo Municipal Carmen Funes in Plaza Huincul, Argentina, has an Argentinosaurus reconstructed skeleton mount that is 39.7 meters (130 ft) long.
There were larger dinosaurs, but knowledge of them is based entirely on a small number of fragmentary fossils. Most of the largest herbivorous specimens on record were discovered in the 1970s or later, and include the massive Argentinosaurus, which may have weighed 80000 to 100000 kilograms (90 to 110 short tons) and reached lengths of 30 to 40 meters (98 to 131 ft); some of the longest were the 33.5-meter (110 ft) long Diplodocus hallorum (formerly Seismosaurus), the 33-to-34-meter (108 to 112 ft) long Supersaurus, and 37-meter (121 ft) long Patagotitan; and the tallest, the 18-meter (59 ft) tall Sauroposeidon, which could have reached a sixth-floor window. There were a few dinosaurs that was considered either the heaviest and longest. The most famous one include Amphicoelias fragillimus, known only from a now lost partial vertebral neural arch described in 1878. Extrapolating from the illustration of this bone, the animal may have been 58 meters (190 ft) long and weighed 122400 kg (270000 lb). However, recent research have placed Amphicoelias from the long, gracile diplodocid to the shorter but much stockier rebbachisaurid. Now renamed as Maraapunisaurus, this sauropod now stands as much as 40 meters (130 ft) long and weigh as much as 120000 kg (264555 lb). Another contender of this title includes Bruhathkayosaurus matleyi, a incredibly controversial taxon that was recently confirmed to exist after archived photos were uncovered. Bruhathkayosaurus was a titanosaur and would have most likely weighed more than even Marrapunisaurus. Recent size estimates in 2023 have placed this sauropod reaching lengths of up to 44.1 m (145 ft) long and a colossal weight range of around 110000-170000 kg (242508-374785 lb), if these upper estimates up true, Bruhathkayosaurus would have rivaled the blue whale and Perucetus colossus as one of the largest animals to have ever existed.
The largest carnivorous dinosaur was Spinosaurus, reaching a length of 12.6 to 18 meters (41 to 59 ft), and weighing 7 to 20.9 metric tons (7.7 to 23.0 short tons). Other large carnivorous theropods included Giganotosaurus, Carcharodontosaurus and Tyrannosaurus. Therizinosaurus and Deinocheirus were among the tallest of the theropods. The largest ornithischian dinosaur was probably the hadrosaurid Shantungosaurus giganteus which measured 16.6 meters (54 ft). The largest individuals may have weighed as much as 16 metric tons (18 short tons).
The smallest dinosaur known is the bee hummingbird, with a length of only 5 centimeters (2.0 in) and mass of around 1.8 g (0.063 oz). The smallest known non-avialan dinosaurs were about the size of pigeons and were those theropods most closely related to birds. For example, Anchiornis huxleyi is currently the smallest non-avialan dinosaur described from an adult specimen, with an estimated weight of 110 g (3.9 oz) and a total skeletal length of 34 centimeters (1.12 ft). The smallest herbivorous non-avialan dinosaurs included Microceratus and Wannanosaurus, at about 60 centimeters (2.0 ft) long each.
Many modern birds are highly social, often found living in flocks. There is general agreement that some behaviors that are common in birds, as well as in crocodiles (closest living relatives of birds), were also common among extinct dinosaur groups. Interpretations of behavior in fossil species are generally based on the pose of skeletons and their habitat, computer simulations of their biomechanics, and comparisons with modern animals in similar ecological niches.
The first potential evidence for herding or flocking as a widespread behavior common to many dinosaur groups in addition to birds was the 1878 discovery of 31 Iguanodon, ornithischians that were then thought to have perished together in Bernissart, Belgium, after they fell into a deep, flooded sinkhole and drowned. Other mass-death sites have been discovered subsequently. Those, along with multiple trackways, suggest that gregarious behavior was common in many early dinosaur species. Trackways of hundreds or even thousands of herbivores indicate that duck-billed (hadrosaurids) may have moved in great herds, like the American bison or the African springbok. Sauropod tracks document that these animals traveled in groups composed of several different species, at least in Oxfordshire, England, although there is no evidence for specific herd structures. Congregating into herds may have evolved for defense, for migratory purposes, or to provide protection for young. There is evidence that many types of slow-growing dinosaurs, including various theropods, sauropods, ankylosaurians, ornithopods, and ceratopsians, formed aggregations of immature individuals. One example is a site in Inner Mongolia that has yielded remains of over 20 Sinornithomimus, from one to seven years old. This assemblage is interpreted as a social group that was trapped in mud. The interpretation of dinosaurs as gregarious has also extended to depicting carnivorous theropods as pack hunters working together to bring down large prey. However, this lifestyle is uncommon among modern birds, crocodiles, and other reptiles, and the taphonomic evidence suggesting mammal-like pack hunting in such theropods as Deinonychus and Allosaurus can also be interpreted as the results of fatal disputes between feeding animals, as is seen in many modern diapsid predators.
The crests and frills of some dinosaurs, like the marginocephalians, theropods and lambeosaurines, may have been too fragile to be used for active defense, and so they were likely used for sexual or aggressive displays, though little is known about dinosaur mating and territorialism. Head wounds from bites suggest that theropods, at least, engaged in active aggressive confrontations.
From a behavioral standpoint, one of the most valuable dinosaur fossils was discovered in the Gobi Desert in 1971. It included a Velociraptor attacking a Protoceratops, providing evidence that dinosaurs did indeed attack each other. Additional evidence for attacking live prey is the partially healed tail of an Edmontosaurus, a hadrosaurid dinosaur; the tail is damaged in such a way that shows the animal was bitten by a tyrannosaur but survived. Cannibalism amongst some species of dinosaurs was confirmed by tooth marks found in Madagascar in 2003, involving the theropod Majungasaurus.
Comparisons between the scleral rings of dinosaurs and modern birds and reptiles have been used to infer daily activity patterns of dinosaurs. Although it has been suggested that most dinosaurs were active during the day, these comparisons have shown that small predatory dinosaurs such as dromaeosaurids, Juravenator, and Megapnosaurus were likely nocturnal. Large and medium-sized herbivorous and omnivorous dinosaurs such as ceratopsians, sauropodomorphs, hadrosaurids, ornithomimosaurs may have been cathemeral, active during short intervals throughout the day, although the small ornithischian Agilisaurus was inferred to be diurnal.
Based on fossil evidence from dinosaurs such as Oryctodromeus, some ornithischian species seem to have led a partially fossorial (burrowing) lifestyle. Many modern birds are arboreal (tree climbing), and this was also true of many Mesozoic birds, especially the enantiornithines. While some early bird-like species may have already been arboreal as well (including dromaeosaurids) such as Microraptor) most non-avialan dinosaurs seem to have relied on land-based locomotion. A good understanding of how dinosaurs moved on the ground is key to models of dinosaur behavior; the science of biomechanics, pioneered by Robert McNeill Alexander, has provided significant insight in this area. For example, studies of the forces exerted by muscles and gravity on dinosaurs' skeletal structure have investigated how fast dinosaurs could run, whether diplodocids could create sonic booms via whip-like tail snapping, and whether sauropods could float.
Modern birds are known to communicate using visual and auditory signals, and the wide diversity of visual display structures among fossil dinosaur groups, such as horns, frills, crests, sails, and feathers, suggests that visual communication has always been important in dinosaur biology. Reconstruction of the plumage color of Anchiornis, suggest the importance of color in visual communication in non-avian dinosaurs. Vocalization in non-avian dinosaurs is less certain. In birds, the larynx plays no role in sound production. Instead they vocalize with a novel organ called the syrinx, located further down the trachea. The earliest remains of a syrinx was found in a specimen of the duck-like Vegavis iaai dated 69 –66 million years ago, and this organ is unlikely to have existed in non-avian dinosaurs.
Paleontologist Phil Senter has suggested that since non-avian dinosaurs did not have a syrinx, and their next closest living relatives, crocodilians, use the larynx, they could not vocalize as the common ancestor would have been mute. He states that they mostly on visual displays and possibly non-vocal acoustic sounds like hissing, jaw grinding or clapping, splashing and wing beating (possible in winged maniraptoran dinosaurs). Other researchers have countered that vocalizations also exist in turtles, the closest relatives of archosaurs, suggesting that the trait is ancestral to their lineage. In addition, vocal communication in dinosaurs is indicated by the development of advanced hearing in nearly all major groups. Hence the syrinx may have supplemented and then replaced the larynx as a vocal organ rather than there being a "silent period" in bird evolution.
In 2023, a fossilized larynx was described from a specimen of the ankylosaurid Pinacosaurus. The structure was composed of cricoid and arytenoid cartilages, similar to those of non-avian reptiles. However, the mobile cricoid-arytenoid joint and long arytenoid cartilages would have allowed for air-flow control similar to that of birds, and thus could have made bird-like vocalizations. In addition, the cartilages were ossified, implying that laryngeal ossification is a feature of some non-avian dinosaurs. A 2016 study concludes that some dinosaurs may have produced closed mouth vocalizations like cooing, hooting and booming. These occur in both reptiles and birds and involve inflating the esophagus or tracheal pouches. Such vocalizations evolved independently in extant archosaurs numerous times, following increases in body size. The crests of some hadrosaurids and the nasal chambers of ankylosaurids have been suggested to have functioned in acoustic resonance.
All dinosaurs laid amniotic eggs. Dinosaur eggs were usually laid in a nest. Most species create somewhat elaborate nests which can be cups, domes, plates, beds scrapes, mounds, or burrows. Some species of modern bird have no nests; the cliff-nesting common guillemot lays its eggs on bare rock, and male emperor penguins keep eggs between their body and feet. Primitive birds and many non-avialan dinosaurs often lay eggs in communal nests, with males primarily incubating the eggs. While modern birds have only one functional oviduct and lay one egg at a time, more primitive birds and dinosaurs had two oviducts, like crocodiles. Some non-avialan dinosaurs, such as Troodon, exhibited iterative laying, where the adult might lay a pair of eggs every one or two days, and then ensured simultaneous hatching by delaying brooding until all eggs were laid.
When laying eggs, females grow a special type of bone between the hard outer bone and the marrow of their limbs. This medullary bone, which is rich in calcium, is used to make eggshells. A discovery of features in a Tyrannosaurus skeleton provided evidence of medullary bone in extinct dinosaurs and, for the first time, allowed paleontologists to establish the sex of a fossil dinosaur specimen. Further research has found medullary bone in the carnosaur Allosaurus and the ornithopod Tenontosaurus. Because the line of dinosaurs that includes Allosaurus and Tyrannosaurus diverged from the line that led to Tenontosaurus very early in the evolution of dinosaurs, this suggests that the production of medullary tissue is a general characteristic of all dinosaurs.
Another widespread trait among modern birds (but see below in regards to fossil groups and extant megapodes) is parental care for young after hatching. Jack Horner's 1978 discovery of a Maiasaura ("good mother lizard") nesting ground in Montana demonstrated that parental care continued long after birth among ornithopods. A specimen of the oviraptorid Citipati osmolskae was discovered in a chicken-like brooding position in 1993, which may indicate that they had begun using an insulating layer of feathers to keep the eggs warm. An embryo of the basal sauropodomorph Massospondylus was found without teeth, indicating that some parental care was required to feed the young dinosaurs. Trackways have also confirmed parental behavior among ornithopods from the Isle of Skye in northwestern Scotland.
However, there is ample evidence of precociality or superprecociality among many dinosaur species, particularly theropods. For instance, non-ornithuromorph birds have been abundantly demonstrated to have had slow growth rates, megapode-like egg burying behavior and the ability to fly soon after birth. Both Tyrannosaurus and Troodon had juveniles with clear superprecociality and likely occupying different ecological niches than the adults. Superprecociality has been inferred for sauropods.
Genital structures are unlikely to fossilize as they lack scales that may allow preservation via pigmentation or residual calcium phosphate salts. In 2021, the best preserved specimen of a dinosaur's cloacal vent exterior was described for Psittacosaurus, demonstrating lateral swellings similar to crocodylian musk glands used in social displays by both sexes and pigmented regions which could also reflect a signalling function. However, this specimen on its own does not offer enough information to determine whether this dinosaur had sexual signalling functions; it only supports the possibility. Cloacal visual signalling can occur in either males or females in living birds, making it unlikely to be useful to determine sex for extinct dinosaurs.
Because both modern crocodilians and birds have four-chambered hearts (albeit modified in crocodilians), it is likely that this is a trait shared by all archosaurs, including all dinosaurs. While all modern birds have high metabolisms and are endothermic ("warm-blooded"), a vigorous debate has been ongoing since the 1960s regarding how far back in the dinosaur lineage this trait extended. Various researchers have supported dinosaurs as being endothermic, ectothermic ("cold-blooded"), or somewhere in between. An emerging consensus among researchers is that, while different lineages of dinosaurs would have had different metabolisms, most of them had higher metabolic rates than other reptiles but lower than living birds and mammals, which is termed mesothermy by some. Evidence from crocodiles and their extinct relatives suggests that such elevated metabolisms could have developed in the earliest archosaurs, which were the common ancestors of dinosaurs and crocodiles.
After non-avian dinosaurs were discovered, paleontologists first posited that they were ectothermic. This was used to imply that the ancient dinosaurs were relatively slow, sluggish organisms, even though many modern reptiles are fast and light-footed despite relying on external sources of heat to regulate their body temperature. The idea of dinosaurs as ectothermic remained a prevalent view until Robert T. Bakker, an early proponent of dinosaur endothermy, published an influential paper on the topic in 1968. Bakker specifically used anatomical and ecological evidence to argue that sauropods, which had hitherto been depicted as sprawling aquatic animals with their tails dragging on the ground, were endotherms that lived vigorous, terrestrial lives. In 1972, Bakker expanded on his arguments based on energy requirements and predator-prey ratios. This was one of the seminal results that led to the dinosaur renaissance.
One of the greatest contributions to the modern understanding of dinosaur physiology has been paleohistology, the study of microscopic tissue structure in dinosaurs. From the 1960s forward, Armand de Ricqlès suggested that the presence of fibrolamellar bone—bony tissue with an irregular, fibrous texture and filled with blood vessels—was indicative of consistently fast growth and therefore endothermy. Fibrolamellar bone was common in both dinosaurs and pterosaurs, though not universally present. This has led to a significant body of work in reconstructing growth curves and modeling the evolution of growth rates across various dinosaur lineages, which has suggested overall that dinosaurs grew faster than living reptiles. Other lines of evidence suggesting endothermy include the presence of feathers and other types of body coverings in many lineages (see § Feathers); more consistent ratios of the isotope oxygen-18 in bony tissue compared to ectotherms, particularly as latitude and thus air temperature varied, which suggests stable internal temperatures (although these ratios can be altered during fossilization); and the discovery of polar dinosaurs, which lived in Australia, Antarctica, and Alaska when these places would have had cool, temperate climates.
In saurischian dinosaurs, higher metabolisms were supported by the evolution of the avian respiratory system, characterized by an extensive system of air sacs that extended the lungs and invaded many of the bones in the skeleton, making them hollow. Such respiratory systems, which may have appeared in the earliest saurischians, would have provided them with more oxygen compared to a mammal of similar size, while also having a larger resting tidal volume and requiring a lower breathing frequency, which would have allowed them to sustain higher activity levels. The rapid airflow would also have been an effective cooling mechanism, which in conjunction with a lower metabolic rate would have prevented large sauropods from overheating. These traits may have enabled sauropods to grow quickly to gigantic sizes. Sauropods may also have benefitted from their size—their small surface area to volume ratio meant that they would have been able to thermoregulate more easily, a phenomenon termed gigantothermy.
Like other reptiles, dinosaurs are primarily uricotelic, that is, their kidneys extract nitrogenous wastes from their bloodstream and excrete it as uric acid instead of urea or ammonia via the ureters into the intestine. This would have helped them to conserve water. In most living species, uric acid is excreted along with feces as a semisolid waste. However, at least some modern birds (such as hummingbirds) can be facultatively ammonotelic, excreting most of the nitrogenous wastes as ammonia. This material, as well as the output of the intestines, emerges from the cloaca. In addition, many species regurgitate pellets, and fossil pellets are known as early as the Jurassic from Anchiornis.
The size and shape of the brain can be partly reconstructed based on the surrounding bones. In 1896, Marsh calculated ratios between brain weight and body weight of seven species of dinosaurs, showing that the brain of dinosaurs was proportionally smaller than in today's crocodiles, and that the brain of Stegosaurus was smaller than in any living land vertebrate. This contributed to the widespread public notion of dinosaurs as being sluggish and extraordinarily stupid. Harry Jerison, in 1973, showed that proportionally smaller brains are expected at larger body sizes, and that brain size in dinosaurs was not smaller than expected when compared to living reptiles. Later research showed that relative brain size progressively increased during the evolution of theropods, with the highest intelligence – comparable to that of modern birds – calculated for the troodontid Troodon.
The possibility that dinosaurs were the ancestors of birds was first suggested in 1868 by Thomas Henry Huxley. After the work of Gerhard Heilmann in the early 20th century, the theory of birds as dinosaur descendants was abandoned in favor of the idea of them being descendants of generalized thecodonts, with the key piece of evidence being the supposed lack of clavicles in dinosaurs. However, as later discoveries showed, clavicles (or a single fused wishbone, which derived from separate clavicles) were not actually absent; they had been found as early as 1924 in Oviraptor, but misidentified as an interclavicle. In the 1970s, Ostrom revived the dinosaur–bird theory, which gained momentum in the coming decades with the advent of cladistic analysis, and a great increase in the discovery of small theropods and early birds. Of particular note have been the fossils of the Jehol Biota, where a variety of theropods and early birds have been found, often with feathers of some type. Birds share over a hundred distinct anatomical features with theropod dinosaurs, which are now generally accepted to have been their closest ancient relatives. They are most closely allied with maniraptoran coelurosaurs. A minority of scientists, most notably Alan Feduccia and Larry Martin, have proposed other evolutionary paths, including revised versions of Heilmann's basal archosaur proposal, or that maniraptoran theropods are the ancestors of birds but themselves are not dinosaurs, only convergent with dinosaurs.
Feathers are one of the most recognizable characteristics of modern birds, and a trait that was also shared by several non-avian dinosaurs. Based on the current distribution of fossil evidence, it appears that feathers were an ancestral dinosaurian trait, though one that may have been selectively lost in some species. Direct fossil evidence of feathers or feather-like structures has been discovered in a diverse array of species in many non-avian dinosaur groups, both among saurischians and ornithischians. Simple, branched, feather-like structures are known from heterodontosaurids, primitive neornithischians, and theropods, and primitive ceratopsians. Evidence for true, vaned feathers similar to the flight feathers of modern birds has been found only in the theropod subgroup Maniraptora, which includes oviraptorosaurs, troodontids, dromaeosaurids, and birds. Feather-like structures known as pycnofibres have also been found in pterosaurs.
However, researchers do not agree regarding whether these structures share a common origin between lineages (i.e., they are homologous), or if they were the result of widespread experimentation with skin coverings among ornithodirans. If the former is the case, filaments may have been common in the ornithodiran lineage and evolved before the appearance of dinosaurs themselves. Research into the genetics of American alligators has revealed that crocodylian scutes do possess feather-keratins during embryonic development, but these keratins are not expressed by the animals before hatching. The description of feathered dinosaurs has not been without controversy in general; perhaps the most vocal critics have been Alan Feduccia and Theagarten Lingham-Soliar, who have proposed that some purported feather-like fossils are the result of the decomposition of collagenous fiber that underlaid the dinosaurs' skin, and that maniraptoran dinosaurs with vaned feathers were not actually dinosaurs, but convergent with dinosaurs. However, their views have for the most part not been accepted by other researchers, to the point that the scientific nature of Feduccia's proposals has been questioned.
Archaeopteryx was the first fossil found that revealed a potential connection between dinosaurs and birds. It is considered a transitional fossil, in that it displays features of both groups. Brought to light just two years after Charles Darwin's seminal On the Origin of Species (1859), its discovery spurred the nascent debate between proponents of evolutionary biology and creationism. This early bird is so dinosaur-like that, without a clear impression of feathers in the surrounding rock, at least one specimen was mistaken for the small theropod Compsognathus. Since the 1990s, a number of additional feathered dinosaurs have been found, providing even stronger evidence of the close relationship between dinosaurs and modern birds. Many of these specimens were unearthed in the lagerstätten of the Jehol Biota. If feather-like structures were indeed widely present among non-avian dinosaurs, the lack of abundant fossil evidence for them may be due to the fact that delicate features like skin and feathers are seldom preserved by fossilization and thus often absent from the fossil record.
Because feathers are often associated with birds, feathered dinosaurs are often touted as the missing link between birds and dinosaurs. However, the multiple skeletal features also shared by the two groups represent another important line of evidence for paleontologists. Areas of the skeleton with important similarities include the neck, pubis, wrist (semi-lunate carpal), arm and pectoral girdle, furcula (wishbone), and breast bone. Comparison of bird and dinosaur skeletons through cladistic analysis strengthens the case for the link.
Large meat-eating dinosaurs had a complex system of air sacs similar to those found in modern birds, according to a 2005 investigation led by Patrick M. O'Connor. The lungs of theropod dinosaurs (carnivores that walked on two legs and had bird-like feet) likely pumped air into hollow sacs in their skeletons, as is the case in birds. "What was once formally considered unique to birds was present in some form in the ancestors of birds", O'Connor said. In 2008, scientists described Aerosteon riocoloradensis, the skeleton of which supplies the strongest evidence to date of a dinosaur with a bird-like breathing system. CT scanning of Aerosteon's fossil bones revealed evidence for the existence of air sacs within the animal's body cavity.
Fossils of the troodonts Mei and Sinornithoides demonstrate that some dinosaurs slept with their heads tucked under their arms. This behavior, which may have helped to keep the head warm, is also characteristic of modern birds. Several deinonychosaur and oviraptorosaur specimens have also been found preserved on top of their nests, likely brooding in a bird-like manner. The ratio between egg volume and body mass of adults among these dinosaurs suggest that the eggs were primarily brooded by the male, and that the young were highly precocial, similar to many modern ground-dwelling birds.
Some dinosaurs are known to have used gizzard stones like modern birds. These stones are swallowed by animals to aid digestion and break down food and hard fibers once they enter the stomach. When found in association with fossils, gizzard stones are called gastroliths.
All non-avian dinosaurs and most lineages of birds became extinct in a mass extinction event, called the Cretaceous–Paleogene (K-Pg) extinction event, at the end of the Cretaceous period. Above the Cretaceous–Paleogene boundary, which has been dated to 66.038 ± 0.025 million years ago, fossils of non-avian dinosaurs disappear abruptly; the absence of dinosaur fossils was historically used to assign rocks to the ensuing Cenozoic. The nature of the event that caused this mass extinction has been extensively studied since the 1970s, leading to the development of two mechanisms that are thought to have played major roles: an extraterrestrial impact event in the Yucatán Peninsula, along with flood basalt volcanism in India. However, the specific mechanisms of the extinction event and the extent of its effects on dinosaurs are still areas of ongoing research. Alongside dinosaurs, many other groups of animals became extinct: pterosaurs, marine reptiles such as mosasaurs and plesiosaurs, several groups of mammals, ammonites (nautilus-like mollusks), rudists (reef-building bivalves), and various groups of marine plankton. In all, approximately 47% of genera and 76% of species on Earth became extinct during the K-Pg extinction event. The relatively large size of most dinosaurs and the low diversity of small-bodied dinosaur species at the end of the Cretaceous may have contributed to their extinction; the extinction of the bird lineages that did not survive may also have been caused by a dependence on forest habitats or a lack of adaptations to eating seeds for survival.
Just before the K-Pg extinction event, the number of non-avian dinosaur species that existed globally has been estimated at between 628 and 1078. It remains uncertain whether the diversity of dinosaurs was in gradual decline before the K-Pg extinction event, or whether dinosaurs were actually thriving prior to the extinction. Rock formations from the Maastrichtian epoch, which directly preceded the extinction, have been found to have lower diversity than the preceding Campanian epoch, which led to the prevailing view of a long-term decline in diversity. However, these comparisons did not account either for varying preservation potential between rock units or for different extents of exploration and excavation. In 1984, Dale Russell carried out an analysis to account for these biases, and found no evidence of a decline; another analysis by David Fastovsky and colleagues in 2004 even showed that dinosaur diversity continually increased until the extinction, but this analysis has been rebutted. Since then, different approaches based on statistics and mathematical models have variously supported either a sudden extinction or a gradual decline. End-Cretaceous trends in diversity may have varied between dinosaur lineages: it has been suggested that sauropods were not in decline, while ornithischians and theropods were in decline.
The bolide impact hypothesis, first brought to wide attention in 1980 by Walter Alvarez, Luis Alvarez, and colleagues, attributes the K-Pg extinction event to a bolide (extraterrestrial projectile) impact. Alvarez and colleagues proposed that a sudden increase in iridium levels, recorded around the world in rock deposits at the Cretaceous–Paleogene boundary, was direct evidence of the impact. Shocked quartz, indicative of a strong shockwave emanating from an impact, was also found worldwide. The actual impact site remained elusive until a crater measuring 180 km (110 mi) wide was discovered in the Yucatán Peninsula of southeastern Mexico, and was publicized in a 1991 paper by Alan Hildebrand and colleagues. Now, the bulk of the evidence suggests that a bolide 5 to 15 kilometers (3 to 9+1⁄2 miles) wide impacted the Yucatán Peninsula 66 million years ago, forming this crater and creating a "kill mechanism" that triggered the extinction event.
Within hours, the Chicxulub impact would have created immediate effects such as earthquakes, tsunamis, and a global firestorm that likely killed unsheltered animals and started wildfires. However, it would also have had longer-term consequences for the environment. Within days, sulfate aerosols released from rocks at the impact site would have contributed to acid rain and ocean acidification. Soot aerosols are thought to have spread around the world over the ensuing months and years; they would have cooled the surface of the Earth by reflecting thermal radiation, and greatly slowed photosynthesis by blocking out sunlight, thus creating an impact winter. (This role was ascribed to sulfate aerosols until experiments demonstrated otherwise.) The cessation of photosynthesis would have led to the collapse of food webs depending on leafy plants, which included all dinosaurs save for grain-eating birds.
At the time of the K-Pg extinction, the Deccan Traps flood basalts of India were actively erupting. The eruptions can be separated into three phases around the K-Pg boundary, two prior to the boundary and one after. The second phase, which occurred very close to the boundary, would have extruded 70 to 80% of the volume of these eruptions in intermittent pulses that occurred around 100,000 years apart. Greenhouse gases such as carbon dioxide and sulfur dioxide would have been released by this volcanic activity, resulting in climate change through temperature perturbations of roughly 3 °C (5.4 °F) but possibly as high as 7 °C (13 °F). Like the Chicxulub impact, the eruptions may also have released sulfate aerosols, which would have caused acid rain and global cooling. However, due to large error margins in the dating of the eruptions, the role of the Deccan Traps in the K-Pg extinction remains unclear.
Before 2000, arguments that the Deccan Traps eruptions—as opposed to the Chicxulub impact—caused the extinction were usually linked to the view that the extinction was gradual. Prior to the discovery of the Chicxulub crater, the Deccan Traps were used to explain the global iridium layer; even after the crater's discovery, the impact was still thought to only have had a regional, not global, effect on the extinction event. In response, Luis Alvarez rejected volcanic activity as an explanation for the iridium layer and the extinction as a whole. Since then, however, most researchers have adopted a more moderate position, which identifies the Chicxulub impact as the primary progenitor of the extinction while also recognizing that the Deccan Traps may also have played a role. Walter Alvarez himself has acknowledged that the Deccan Traps and other ecological factors may have contributed to the extinctions in addition to the Chicxulub impact. Some estimates have placed the start of the second phase in the Deccan Traps eruptions within 50,000 years after the Chicxulub impact. Combined with mathematical modelling of the seismic waves that would have been generated by the impact, this has led to the suggestion that the Chicxulub impact may have triggered these eruptions by increasing the permeability of the mantle plume underlying the Deccan Traps.
Whether the Deccan Traps were a major cause of the extinction, on par with the Chicxulub impact, remains uncertain. Proponents consider the climatic impact of the sulfur dioxide released to have been on par with the Chicxulub impact, and also note the role of flood basalt volcanism in other mass extinctions like the Permian-Triassic extinction event. They consider the Chicxulub impact to have worsened the ongoing climate change caused by the eruptions. Meanwhile, detractors point out the sudden nature of the extinction and that other pulses in Deccan Traps activity of comparable magnitude did not appear to have caused extinctions. They also contend that the causes of different mass extinctions should be assessed separately. In 2020, Alfio Chiarenza and colleagues suggested that the Deccan Traps may even have had the opposite effect: they suggested that the long-term warming caused by its carbon dioxide emissions may have dampened the impact winter from the Chicxulub impact.
Non-avian dinosaur remains have occasionally been found above the K-Pg boundary. In 2000, Spencer Lucas and colleagues reported the discovery of a single hadrosaur right femur in the San Juan Basin of New Mexico, and described it as evidence of Paleocene dinosaurs. The rock unit in which the bone was discovered has been dated to the early Paleocene epoch, approximately 64.8 million years ago. If the bone was not re-deposited by weathering action, it would provide evidence that some dinosaur populations survived at least half a million years into the Cenozoic. Other evidence includes the presence of dinosaur remains in the Hell Creek Formation up to 1.3 m (4.3 ft) above the Cretaceous–Paleogene boundary, representing 40,000 years of elapsed time. This has been used to support the view that the K-Pg extinction was gradual. However, these supposed Paleocene dinosaurs are considered by many other researchers to be reworked, that is, washed out of their original locations and then re-buried in younger sediments. The age estimates have also been considered unreliable.
By human standards, dinosaurs were creatures of fantastic appearance and often enormous size. As such, they have captured the popular imagination and become an enduring part of human culture. The entry of the word "dinosaur" into the common vernacular reflects the animals' cultural importance: in English, "dinosaur" is commonly used to describe anything that is impractically large, obsolete, or bound for extinction.
Public enthusiasm for dinosaurs first developed in Victorian England, where in 1854, three decades after the first scientific descriptions of dinosaur remains, a menagerie of lifelike dinosaur sculptures was unveiled in London's Crystal Palace Park. The Crystal Palace dinosaurs proved so popular that a strong market in smaller replicas soon developed. In subsequent decades, dinosaur exhibits opened at parks and museums around the world, ensuring that successive generations would be introduced to the animals in an immersive and exciting way. The enduring popularity of dinosaurs, in its turn, has resulted in significant public funding for dinosaur science, and has frequently spurred new discoveries. In the United States, for example, the competition between museums for public attention led directly to the Bone Wars of the 1880s and 1890s, during which a pair of feuding paleontologists made enormous scientific contributions.
The popular preoccupation with dinosaurs has ensured their appearance in literature, film, and other media. Beginning in 1852 with a passing mention in Charles Dickens' Bleak House, dinosaurs have been featured in large numbers of fictional works. Jules Verne's 1864 novel Journey to the Center of the Earth, Sir Arthur Conan Doyle's 1912 book The Lost World, the 1914 animated film Gertie the Dinosaur (featuring the first animated dinosaur), the iconic 1933 film King Kong, the 1954 Godzilla and its many sequels, the best-selling 1990 novel Jurassic Park by Michael Crichton and its 1993 film adaptation are just a few notable examples of dinosaur appearances in fiction. Authors of general-interest non-fiction works about dinosaurs, including some prominent paleontologists, have often sought to use the animals as a way to educate readers about science in general. Dinosaurs are ubiquitous in advertising; numerous companies have referenced dinosaurs in printed or televised advertisements, either in order to sell their own products or in order to characterize their rivals as slow-moving, dim-witted, or obsolete. | [
{
"paragraph_id": 0,
"text": "Dinosaurs are a diverse group of reptiles of the clade Dinosauria. They first appeared during the Triassic period, between 243 and 233.23 million years ago (mya), although the exact origin and timing of the evolution of dinosaurs is a subject of active research. They became the dominant terrestrial vertebrates after the Triassic–Jurassic extinction event 201.3 mya and their dominance continued throughout the Jurassic and Cretaceous periods. The fossil record shows that birds are feathered dinosaurs, having evolved from earlier theropods during the Late Jurassic epoch, and are the only dinosaur lineage known to have survived the Cretaceous–Paleogene extinction event approximately 66 mya. Dinosaurs can therefore be divided into avian dinosaurs—birds—and the extinct non-avian dinosaurs, which are all dinosaurs other than birds.",
"title": ""
},
{
"paragraph_id": 1,
"text": "Dinosaurs are varied from taxonomic, morphological and ecological standpoints. Birds, at over 10,700 living species, are among the most diverse groups of vertebrates. Using fossil evidence, paleontologists have identified over 900 distinct genera and more than 1,000 different species of non-avian dinosaurs. Dinosaurs are represented on every continent by both extant species (birds) and fossil remains. Through the first half of the 20th century, before birds were recognized as dinosaurs, most of the scientific community believed dinosaurs to have been sluggish and cold-blooded. Most research conducted since the 1970s, however, has indicated that dinosaurs were active animals with elevated metabolisms and numerous adaptations for social interaction. Some were herbivorous, others carnivorous. Evidence suggests that all dinosaurs were egg-laying, and that nest-building was a trait shared by many dinosaurs, both avian and non-avian.",
"title": ""
},
{
"paragraph_id": 2,
"text": "While dinosaurs were ancestrally bipedal, many extinct groups included quadrupedal species, and some were able to shift between these stances. Elaborate display structures such as horns or crests are common to all dinosaur groups, and some extinct groups developed skeletal modifications such as bony armor and spines. While the dinosaurs' modern-day surviving avian lineage (birds) are generally small due to the constraints of flight, many prehistoric dinosaurs (non-avian and avian) were large-bodied—the largest sauropod dinosaurs are estimated to have reached lengths of 39.7 meters (130 feet) and heights of 18 m (59 ft) and were the largest land animals of all time. The misconception that non-avian dinosaurs were uniformly gigantic is based in part on preservation bias, as large, sturdy bones are more likely to last until they are fossilized. Many dinosaurs were quite small, some measuring about 50 centimeters (20 inches) in length.",
"title": ""
},
{
"paragraph_id": 3,
"text": "The first dinosaur fossils were recognized in the early 19th century, with the name \"dinosaur\" (meaning \"terrible lizard\") being coined by Sir Richard Owen in 1842 to refer to these \"great fossil lizards\". Since then, mounted fossil dinosaur skeletons have been major attractions at museums worldwide, and dinosaurs have become an enduring part of popular culture. The large sizes of some dinosaurs, as well as their seemingly monstrous and fantastic nature, have ensured their regular appearance in best-selling books and films, such as Jurassic Park. Persistent public enthusiasm for the animals has resulted in significant funding for dinosaur science, and new discoveries are regularly covered by the media.",
"title": ""
},
{
"paragraph_id": 4,
"text": "Under phylogenetic nomenclature, dinosaurs are usually defined as the group consisting of the most recent common ancestor (MRCA) of Triceratops and modern birds (Neornithes), and all its descendants. It has also been suggested that Dinosauria be defined with respect to the MRCA of Megalosaurus and Iguanodon, because these were two of the three genera cited by Richard Owen when he recognized the Dinosauria. Both definitions result in the same set of animals being defined as dinosaurs: \"Dinosauria = Ornithischia + Saurischia\". This definition includes major groups such as ankylosaurians (armored herbivorous quadrupeds), stegosaurians (plated herbivorous quadrupeds), ceratopsians (bipedal or quadrupedal herbivores with neck frills), pachycephalosaurians (bipedal herbivores with thick skulls), ornithopods (bipedal or quadrupedal herbivores including \"duck-bills\"), theropods (mostly bipedal carnivores and birds), and sauropodomorphs (mostly large herbivorous quadrupeds with long necks and tails).",
"title": "Definition"
},
{
"paragraph_id": 5,
"text": "Birds are the sole surviving dinosaurs. In traditional taxonomy, birds were considered a separate class that had evolved from dinosaurs, a distinct superorder. However, a majority of contemporary paleontologists concerned with dinosaurs reject the traditional style of classification in favor of phylogenetic taxonomy; this approach requires that, for a group to be natural, all descendants of members of the group must be included in the group. Birds belong to the dinosaur subgroup Maniraptora, which are coelurosaurs, which are theropods, which are saurischians.",
"title": "Definition"
},
{
"paragraph_id": 6,
"text": "Research by Matthew G. Baron, David B. Norman, and Paul M. Barrett in 2017 suggested a radical revision of dinosaurian systematics. Phylogenetic analysis by Baron et al. recovered the Ornithischia as being closer to the Theropoda than the Sauropodomorpha, as opposed to the traditional union of theropods with sauropodomorphs. This would cause sauropods and kin to fall outside traditional dinosaurs, so they re-defined Dinosauria as the last common ancestor of Triceratops horridus, Passer domesticus and Diplodocus carnegii, and all of its descendants, to ensure that sauropods and kin remain included as dinosaurs. They also resurrected the clade Ornithoscelida to refer to the group containing Ornithischia and Theropoda.",
"title": "Definition"
},
{
"paragraph_id": 7,
"text": "Using one of the above definitions, dinosaurs can be generally described as archosaurs with hind limbs held erect beneath the body. Other prehistoric animals, including pterosaurs, mosasaurs, ichthyosaurs, plesiosaurs, and Dimetrodon, while often popularly conceived of as dinosaurs, are not taxonomically classified as dinosaurs. Pterosaurs are distantly related to dinosaurs, being members of the clade Ornithodira. The other groups mentioned are, like dinosaurs and pterosaurs, members of Sauropsida (the reptile and bird clade), except Dimetrodon (which is a synapsid). None of them had the erect hind limb posture characteristic of true dinosaurs.",
"title": "Definition"
},
{
"paragraph_id": 8,
"text": "Dinosaurs were the dominant terrestrial vertebrates of the Mesozoic Era, especially the Jurassic and Cretaceous periods. Other groups of animals were restricted in size and niches; mammals, for example, rarely exceeded the size of a domestic cat, and were generally rodent-sized carnivores of small prey. They have always been recognized as an extremely varied group of animals; over 900 non-avian dinosaur genera have been identified with certainty as of 2018, and the total number of genera preserved in the fossil record has been estimated at around 1850, nearly 75% of which remain to be discovered, and 1124 species by 2016. A 1995 study predicted that about 3,400 dinosaur genera ever existed, including many that would not have been preserved in the fossil record.",
"title": "Definition"
},
{
"paragraph_id": 9,
"text": "In 2016, the estimated number of dinosaur species that existed in the Mesozoic was 1,543–2,468. In 2021, the number of modern-day birds (avian dinosaurs) was estimated to be at 10,806 species. Some are herbivorous, others carnivorous, including seed-eaters, fish-eaters, insectivores, and omnivores. While dinosaurs were ancestrally bipedal (as are all modern birds), some prehistoric species were quadrupeds, and others, such as Anchisaurus and Iguanodon, could walk just as easily on two or four legs. Cranial modifications like horns and crests are common dinosaurian traits, and some extinct species had bony armor. Although known for large size, many Mesozoic dinosaurs were human-sized or smaller, and modern birds are generally small in size. Dinosaurs today inhabit every continent, and fossils show that they had achieved global distribution by at least the Early Jurassic epoch. Modern birds inhabit most available habitats, from terrestrial to marine, and there is evidence that some non-avian dinosaurs (such as Microraptor) could fly or at least glide, and others, such as spinosaurids, had semiaquatic habits.",
"title": "Definition"
},
{
"paragraph_id": 10,
"text": "While recent discoveries have made it more difficult to present a universally agreed-upon list of their distinguishing features, nearly all dinosaurs discovered so far share certain modifications to the ancestral archosaurian skeleton, or are clearly descendants of older dinosaurs showing these modifications. Although some later groups of dinosaurs featured further modified versions of these traits, they are considered typical for Dinosauria; the earliest dinosaurs had them and passed them on to their descendants. Such modifications, originating in the most recent common ancestor of a certain taxonomic group, are called the synapomorphies of such a group.",
"title": "Definition"
},
{
"paragraph_id": 11,
"text": "A detailed assessment of archosaur interrelations by Sterling Nesbitt confirmed or found the following twelve unambiguous synapomorphies, some previously known:",
"title": "Definition"
},
{
"paragraph_id": 12,
"text": "Nesbitt found a number of further potential synapomorphies and discounted a number of synapomorphies previously suggested. Some of these are also present in silesaurids, which Nesbitt recovered as a sister group to Dinosauria, including a large anterior trochanter, metatarsals II and IV of subequal length, reduced contact between ischium and pubis, the presence of a cnemial crest on the tibia and of an ascending process on the astragalus, and many others.",
"title": "Definition"
},
{
"paragraph_id": 13,
"text": "A variety of other skeletal features are shared by dinosaurs. However, because they either are common to other groups of archosaurs or were not present in all early dinosaurs, these features are not considered to be synapomorphies. For example, as diapsids, dinosaurs ancestrally had two pairs of Infratemporal fenestrae (openings in the skull behind the eyes), and as members of the diapsid group Archosauria, had additional openings in the snout and lower jaw. Additionally, several characteristics once thought to be synapomorphies are now known to have appeared before dinosaurs, or were absent in the earliest dinosaurs and independently evolved by different dinosaur groups. These include an elongated scapula, or shoulder blade; a sacrum composed of three or more fused vertebrae (three are found in some other archosaurs, but only two are found in Herrerasaurus); and a perforate acetabulum, or hip socket, with a hole at the center of its inside surface (closed in Saturnalia tupiniquim, for example). Another difficulty of determining distinctly dinosaurian features is that early dinosaurs and other archosaurs from the Late Triassic epoch are often poorly known and were similar in many ways; these animals have sometimes been misidentified in the literature.",
"title": "Definition"
},
{
"paragraph_id": 14,
"text": "Dinosaurs stand with their hind limbs erect in a manner similar to most modern mammals, but distinct from most other reptiles, whose limbs sprawl out to either side. This posture is due to the development of a laterally facing recess in the pelvis (usually an open socket) and a corresponding inwardly facing distinct head on the femur. Their erect posture enabled early dinosaurs to breathe easily while moving, which likely permitted stamina and activity levels that surpassed those of \"sprawling\" reptiles. Erect limbs probably also helped support the evolution of large size by reducing bending stresses on limbs. Some non-dinosaurian archosaurs, including rauisuchians, also had erect limbs but achieved this by a \"pillar-erect\" configuration of the hip joint, where instead of having a projection from the femur insert on a socket on the hip, the upper pelvic bone was rotated to form an overhanging shelf.",
"title": "Definition"
},
{
"paragraph_id": 15,
"text": "Dinosaur fossils have been known for millennia, although their true nature was not recognized. The Chinese considered them to be dragon bones and documented them as such. For example, Huayang Guo Zhi (華陽國志), a gazetteer compiled by Chang Qu (常璩) during the Western Jin Dynasty (265–316), reported the discovery of dragon bones at Wucheng in Sichuan Province. Villagers in central China have long unearthed fossilized \"dragon bones\" for use in traditional medicines. In Europe, dinosaur fossils were generally believed to be the remains of giants and other biblical creatures.",
"title": "History of study"
},
{
"paragraph_id": 16,
"text": "Scholarly descriptions of what would now be recognized as dinosaur bones first appeared in the late 17th century in England. Part of a bone, now known to have been the femur of a Megalosaurus, was recovered from a limestone quarry at Cornwell near Chipping Norton, Oxfordshire, in 1676. The fragment was sent to Robert Plot, Professor of Chemistry at the University of Oxford and first curator of the Ashmolean Museum, who published a description in his The Natural History of Oxford-shire (1677). He correctly identified the bone as the lower extremity of the femur of a large animal, and recognized that it was too large to belong to any known species. He, therefore, concluded it to be the femur of a huge human, perhaps a Titan or another type of giant featured in legends. Edward Lhuyd, a friend of Sir Isaac Newton, published Lithophylacii Britannici ichnographia (1699), the first scientific treatment of what would now be recognized as a dinosaur when he described and named a sauropod tooth, \"Rutellum impicatum\", that had been found in Caswell, near Witney, Oxfordshire.",
"title": "History of study"
},
{
"paragraph_id": 17,
"text": "Between 1815 and 1824, the Rev William Buckland, the first Reader of Geology at the University of Oxford, collected more fossilized bones of Megalosaurus and became the first person to describe a non-avian dinosaur in a scientific journal. The second non-avian dinosaur genus to be identified, Iguanodon, was according to legend discovered in 1822 by Mary Ann Mantell – the wife of English geologist Gideon Mantell who in fact had required remains years earlier. Gideon Mantell recognized similarities between his fossils and the bones of modern iguanas. He published his findings in 1825.",
"title": "History of study"
},
{
"paragraph_id": 18,
"text": "The study of these \"great fossil lizards\" soon became of great interest to European and American scientists, and in 1842 the English paleontologist Sir Richard Owen coined the term \"dinosaur\", using it to refer to the \"distinct tribe or sub-order of Saurian Reptiles\" that were then being recognized in England and around the world. The term is derived from Ancient Greek δεινός (deinos) 'terrible, potent or fearfully great', and σαῦρος (sauros) 'lizard or reptile'. Though the taxonomic name has often been interpreted as a reference to dinosaurs' teeth, claws, and other fearsome characteristics, Owen intended it also to evoke their size and majesty. Owen recognized that the remains that had been found so far, Iguanodon, Megalosaurus and Hylaeosaurus, shared distinctive features, and so decided to present them as a distinct taxonomic group. As clarified by British geologist and historian Hugh Torrens, Owen had given a presentation about fossil reptiles to the British Association for the Advancement of Science in 1841, but reports of the time show that Owen did not mention the word \"dinosaur\", nor recognize dinosaurs as a distinct group of reptiles in his address. He introduced the Dinosauria only in the revised text version of his talk published in April of 1842. With the backing of Prince Albert, the husband of Queen Victoria, Owen established the Natural History Museum, London, to display the national collection of dinosaur fossils and other biological and geological exhibits.",
"title": "History of study"
},
{
"paragraph_id": 19,
"text": "In 1858, William Parker Foulke discovered the first known American dinosaur, in marl pits in the small town of Haddonfield, New Jersey. (Although fossils had been found before, their nature had not been correctly discerned.) The creature was named Hadrosaurus foulkii. It was an extremely important find: Hadrosaurus was one of the first nearly complete dinosaur skeletons found (the first was in 1834, in Maidstone, England), and it was clearly a bipedal creature. This was a revolutionary discovery as, until that point, most scientists had believed dinosaurs walked on four feet, like other lizards. Foulke's discoveries sparked a wave of interests in dinosaurs in the United States, known as dinosaur mania.",
"title": "History of study"
},
{
"paragraph_id": 20,
"text": "Dinosaur mania was exemplified by the fierce rivalry between Edward Drinker Cope and Othniel Charles Marsh, both of whom raced to be the first to find new dinosaurs in what came to be known as the Bone Wars. This fight between the two scientists lasted for over 30 years, ending in 1897 when Cope died after spending his entire fortune on the dinosaur hunt. Many valuable dinosaur specimens were damaged or destroyed due to the pair's rough methods: for example, their diggers often used dynamite to unearth bones. Modern paleontologists would find such methods crude and unacceptable, since blasting easily destroys fossil and stratigraphic evidence. Despite their unrefined methods, the contributions of Cope and Marsh to paleontology were vast: Marsh unearthed 86 new species of dinosaur and Cope discovered 56, a total of 142 new species. Cope's collection is now at the American Museum of Natural History in New York City, while Marsh's is at the Peabody Museum of Natural History at Yale University.",
"title": "History of study"
},
{
"paragraph_id": 21,
"text": "World War II caused a pause in palaeontological research; after the war, research attention was also diverted increasingly to fossil mammals rather than dinosaurs, which were seen as sluggish and cold-blooded. At the end of the 1960s, however, the field of dinosaur research experienced a surge in activity that remains ongoing. Several seminal studies led to this activity. First, John Ostrom discovered the bird-like dromaeosaurid theropod Deinonychus and described it in 1969. Its anatomy indicated that it was an active predator that was likely warm-blooded, in marked contrast to the then-prevailing image of dinosaurs. Concurrently, Robert T. Bakker published a series of studies that likewise argued for active lifestyles in dinosaurs based on anatomical and ecological evidence (see § Physiology), which were subsequently summarized in his 1986 book The Dinosaur Heresies.",
"title": "History of study"
},
{
"paragraph_id": 22,
"text": "New revelations were supported by an increase in dinosaur discoveries. Major new dinosaur discoveries have been made by paleontologists working in previously unexplored regions, including India, South America, Madagascar, Antarctica, and most significantly China. Across theropods, sauropodomorphs, and ornithischians, the number of named genera began to increase exponentially in the 1990s. As of 2008, over 30 new species of dinosaurs were named each year. At least sauropodomorphs experienced a further increase in the number of named species in the 2010s, with an average of 9.3 new species having been named each year between 2009 and 2020. As a consequence, more sauropodomorphs were named between 1990 and 2020 than in all previous years combined. These new localities also led to improvements in overall specimen quality, with new species being increasingly named not on scrappy fossils but on more complete skeletons, sometimes from multiple individuals. Better specimens also led to new species being invalidated less frequently. Asian localities have produced the most complete theropod specimens, while North American localities have produced the most complete sauropodomorph specimens.",
"title": "History of study"
},
{
"paragraph_id": 23,
"text": "Prior to the dinosaur renaissance, dinosaurs were mostly classified using the traditional rank-based system of Linnaean taxonomy. The renaissance was also accompanied by the increasingly widespread application of cladistics, a more objective method of classification based on ancestry and shared traits, which has proved tremendously useful in the study of dinosaur systematics and evolution. Cladistic analysis, among other techniques, helps to compensate for an often incomplete and fragmentary fossil record. Reference books summarizing the state of dinosaur research, such as David B. Weishampel and colleagues' The Dinosauria, made knowledge more accessible and spurred further interest in dinosaur research. The release of the first and second editions of The Dinosauria in 1990 and 2004, and of a review paper by Paul Sereno in 1998, were accompanied by increases in the number of published phylogenetic trees for dinosaurs.",
"title": "History of study"
},
{
"paragraph_id": 24,
"text": "Dinosaur fossils are not limited to bones, but also include imprints or mineralized remains of skin coverings, organs, and other tissues. Of these, skin coverings based on keratin proteins are most easily preserved because of their cross-linked, hydrophobic molecular structure. Fossils of keratin-based skin coverings or bony skin coverings are known from most major groups of dinosaurs. Dinosaur fossils with scaly skin impressions have been found since the 19th century. Samuel Beckles discovered a sauropod forelimb with preserved skin in 1852 that was incorrectly attributed to a crocodile; it was correctly attributed by Marsh in 1888 and subject to further study by Reginald Hooley in 1917. Among ornithischians, in 1884 Jacob Wortman found skin impressions on the first known specimen of Edmontosaurus annectens, which were largely destroyed during the specimen's excavation. Owen and Hooley subsequently described skin impressions of Hypsilophodon and Iguanodon in 1885 and 1917. Since then, scale impressions have been most frequently found among hadrosaurids, where the impressions are known from nearly the entire body across multiple specimens.",
"title": "History of study"
},
{
"paragraph_id": 25,
"text": "Starting from the 1990s, major discoveries of exceptionally preserved fossils in deposits known as conservation Lagerstätten contributed to research on dinosaur soft tissues. Chiefly among these were the rocks that produced the Jehol (Early Cretaceous) and Yanliao (Mid-to-Late Jurassic) biotas of northeastern China, from which hundreds of dinosaur specimens bearing impressions of feather-like structures (both closely related to birds and otherwise, see § Origin of birds) have been described by Xing Xu and colleagues. In living reptiles and mammals, pigment-storing cellular structures known as melanosomes are partially responsible for producing colouration. Both chemical traces of melanin and characteristically-shaped melanosomes have been reported from feathers and scales of Jehol and Yanliao dinosaurs, including both theropods and ornithischians. This has enabled multiple full-body reconstructions of dinosaur colouration, such as for Sinosauropteryx and Psittacosaurus by Jakob Vinther and colleagues, and similar techniques have also been extended to dinosaur fossils from other localities. (However, some researchers have also suggested that fossilized melanosomes represent bacterial remains.) Stomach contents in some Jehol and Yanliao dinosaurs closely related to birds have also provided indirect indications of diet and digestive system anatomy (e.g., crops). More concrete evidence of internal anatomy has been reported in Scipionyx from the Pietraroja Plattenkalk of Italy. It preserves portions of the intestines, colon, liver, muscles, and windpipe.",
"title": "History of study"
},
{
"paragraph_id": 26,
"text": "Concurrently, a line of work led by Mary Higby Schweitzer, Jack Horner, and colleagues reported various occurrences of preserved soft tissues and proteins within dinosaur bone fossils. Various mineralized structures that likely represented red blood cells and collagen fibres had been found by Schweitzer and others in tyrannosaurid bones as early as 1991. However, in 2005, Schweitzer and colleagues reported that a femur of Tyrannosaurus preserved soft, flexible tissue within, including blood vessels, bone matrix, and connective tissue (bone fibers) that had retained their microscopic structure. This discovery suggested that original soft tissues could be preserved over geological time, with multiple mechanisms having been proposed. Later, in 2009, Schweitzer and colleagues reported that a Brachylophosaurus femur preserved similar microstructures, and immunohistochemical techniques (based on antibody binding) demonstrated the presence of proteins such as collagen, elastin, and laminin. Both specimens yielded collagen protein sequences that were viable for molecular phylogenetic analyses, which grouped them with birds as would be expected. The extraction of fragmentary DNA has also been reported for both of these fossils, along with a specimen of Hypacrosaurus. In 2015, Sergio Bertazzo and colleagues reported the preservation of collagen fibres and red blood cells in eight Cretaceous dinosaur specimens that did not show any signs of exceptional preservation, indicating that soft tissue may be preserved more commonly than previously thought. Suggestions that these structures represent bacterial biofilms have been rejected, but cross-contamination remains a possibility that is difficult to detect.",
"title": "History of study"
},
{
"paragraph_id": 27,
"text": "Dinosaurs diverged from their archosaur ancestors during the Middle to Late Triassic epochs, roughly 20 million years after the devastating Permian–Triassic extinction event wiped out an estimated 96% of all marine species and 70% of terrestrial vertebrate species approximately 252 million years ago. The oldest dinosaur fossils known from substantial remains date to the Carnian epoch of the Triassic period and have been found primarily in the Ischigualasto and Santa Maria Formations of Argentina and Brazil, and the Pebbly Arkose Formation of Zimbabwe.",
"title": "Evolutionary history"
},
{
"paragraph_id": 28,
"text": "The Ischigualasto Formation (radiometrically dated at 231-230 million years old) has produced the early saurischian Eoraptor, originally considered a member of the Herrerasauridae but now considered to be an early sauropodomorph, along with the herrerasaurids Herrerasaurus and Sanjuansaurus, and the sauropodomorphs Chromogisaurus, Eodromaeus, and Panphagia. Eoraptor's likely resemblance to the common ancestor of all dinosaurs suggests that the first dinosaurs would have been small, bipedal predators. The Santa Maria Formation (radiometrically dated to be older, at 233.23 million years old) has produced the herrerasaurids Gnathovorax and Staurikosaurus, along with the sauropodomorphs Bagualosaurus, Buriolestes, Guaibasaurus, Macrocollum, Nhandumirim, Pampadromaeus, Saturnalia, and Unaysaurus. The Pebbly Arkose Formation, which is of uncertain age but was likely comparable to the other two, has produced the sauropodomorph Mbiresaurus, along with an unnamed herrerasaurid.",
"title": "Evolutionary history"
},
{
"paragraph_id": 29,
"text": "Less well-preserved remains of the sauropodomorphs Jaklapallisaurus and Nambalia, along with the early saurischian Alwalkeria, are known from the Upper Maleri and Lower Maleri Formations of India. The Carnian-aged Chañares Formation of Argentina preserves primitive, dinosaur-like ornithodirans such as Lagosuchus and Lagerpeton in Argentina, making it another important site for understanding dinosaur evolution. These ornithodirans support the model of early dinosaurs as small, bipedal predators. Dinosaurs may have appeared as early as the Anisian epoch of the Triassic, approximately 243 million years ago, which is the age of Nyasasaurus from the Manda Formation of Tanzania. However, its known fossils are too fragmentary to identify it as a dinosaur or only a close relative. The referral of the Manda Formation to the Anisian is also uncertain. Regardless, dinosaurs existed alongside non-dinosaurian ornithodirans for a period of time, with estimates ranging from 5–10 million years to 21 million years.",
"title": "Evolutionary history"
},
{
"paragraph_id": 30,
"text": "When dinosaurs appeared, they were not the dominant terrestrial animals. The terrestrial habitats were occupied by various types of archosauromorphs and therapsids, like cynodonts and rhynchosaurs. Their main competitors were the pseudosuchians, such as aetosaurs, ornithosuchids and rauisuchians, which were more successful than the dinosaurs. Most of these other animals became extinct in the Triassic, in one of two events. First, at about 215 million years ago, a variety of basal archosauromorphs, including the protorosaurs, became extinct. This was followed by the Triassic–Jurassic extinction event (about 201 million years ago), that saw the end of most of the other groups of early archosaurs, like aetosaurs, ornithosuchids, phytosaurs, and rauisuchians. Rhynchosaurs and dicynodonts survived (at least in some areas) at least as late as early –mid Norian and late Norian or earliest Rhaetian stages, respectively, and the exact date of their extinction is uncertain. These losses left behind a land fauna of crocodylomorphs, dinosaurs, mammals, pterosaurians, and turtles. The first few lines of early dinosaurs diversified through the Carnian and Norian stages of the Triassic, possibly by occupying the niches of the groups that became extinct. Also notably, there was a heightened rate of extinction during the Carnian pluvial event.",
"title": "Evolutionary history"
},
{
"paragraph_id": 31,
"text": "Dinosaur evolution after the Triassic followed changes in vegetation and the location of continents. In the Late Triassic and Early Jurassic, the continents were connected as the single landmass Pangaea, and there was a worldwide dinosaur fauna mostly composed of coelophysoid carnivores and early sauropodomorph herbivores. Gymnosperm plants (particularly conifers), a potential food source, radiated in the Late Triassic. Early sauropodomorphs did not have sophisticated mechanisms for processing food in the mouth, and so must have employed other means of breaking down food farther along the digestive tract. The general homogeneity of dinosaurian faunas continued into the Middle and Late Jurassic, where most localities had predators consisting of ceratosaurians, megalosauroids, and allosauroids, and herbivores consisting of stegosaurian ornithischians and large sauropods. Examples of this include the Morrison Formation of North America and Tendaguru Beds of Tanzania. Dinosaurs in China show some differences, with specialized metriacanthosaurid theropods and unusual, long-necked sauropods like Mamenchisaurus. Ankylosaurians and ornithopods were also becoming more common, but primitive sauropodomorphs had become extinct. Conifers and pteridophytes were the most common plants. Sauropods, like earlier sauropodomorphs, were not oral processors, but ornithischians were evolving various means of dealing with food in the mouth, including potential cheek-like organs to keep food in the mouth, and jaw motions to grind food. Another notable evolutionary event of the Jurassic was the appearance of true birds, descended from maniraptoran coelurosaurians.",
"title": "Evolutionary history"
},
{
"paragraph_id": 32,
"text": "By the Early Cretaceous and the ongoing breakup of Pangaea, dinosaurs were becoming strongly differentiated by landmass. The earliest part of this time saw the spread of ankylosaurians, iguanodontians, and brachiosaurids through Europe, North America, and northern Africa. These were later supplemented or replaced in Africa by large spinosaurid and carcharodontosaurid theropods, and rebbachisaurid and titanosaurian sauropods, also found in South America. In Asia, maniraptoran coelurosaurians like dromaeosaurids, troodontids, and oviraptorosaurians became the common theropods, and ankylosaurids and early ceratopsians like Psittacosaurus became important herbivores. Meanwhile, Australia was home to a fauna of basal ankylosaurians, hypsilophodonts, and iguanodontians. The stegosaurians appear to have gone extinct at some point in the late Early Cretaceous or early Late Cretaceous. A major change in the Early Cretaceous, which would be amplified in the Late Cretaceous, was the evolution of flowering plants. At the same time, several groups of dinosaurian herbivores evolved more sophisticated ways to orally process food. Ceratopsians developed a method of slicing with teeth stacked on each other in batteries, and iguanodontians refined a method of grinding with dental batteries, taken to its extreme in hadrosaurids. Some sauropods also evolved tooth batteries, best exemplified by the rebbachisaurid Nigersaurus.",
"title": "Evolutionary history"
},
{
"paragraph_id": 33,
"text": "There were three general dinosaur faunas in the Late Cretaceous. In the northern continents of North America and Asia, the major theropods were tyrannosaurids and various types of smaller maniraptoran theropods, with a predominantly ornithischian herbivore assemblage of hadrosaurids, ceratopsians, ankylosaurids, and pachycephalosaurians. In the southern continents that had made up the now-splitting supercontinent Gondwana, abelisaurids were the common theropods, and titanosaurian sauropods the common herbivores. Finally, in Europe, dromaeosaurids, rhabdodontid iguanodontians, nodosaurid ankylosaurians, and titanosaurian sauropods were prevalent. Flowering plants were greatly radiating, with the first grasses appearing by the end of the Cretaceous. Grinding hadrosaurids and shearing ceratopsians became very diverse across North America and Asia. Theropods were also radiating as herbivores or omnivores, with therizinosaurians and ornithomimosaurians becoming common.",
"title": "Evolutionary history"
},
{
"paragraph_id": 34,
"text": "The Cretaceous–Paleogene extinction event, which occurred approximately 66 million years ago at the end of the Cretaceous, caused the extinction of all dinosaur groups except for the neornithine birds. Some other diapsid groups, including crocodilians, dyrosaurs, sebecosuchians, turtles, lizards, snakes, sphenodontians, and choristoderans, also survived the event.",
"title": "Evolutionary history"
},
{
"paragraph_id": 35,
"text": "The surviving lineages of neornithine birds, including the ancestors of modern ratites, ducks and chickens, and a variety of waterbirds, diversified rapidly at the beginning of the Paleogene period, entering ecological niches left vacant by the extinction of Mesozoic dinosaur groups such as the arboreal enantiornithines, aquatic hesperornithines, and even the larger terrestrial theropods (in the form of Gastornis, eogruiids, bathornithids, ratites, geranoidids, mihirungs, and \"terror birds\"). It is often stated that mammals out-competed the neornithines for dominance of most terrestrial niches but many of these groups co-existed with rich mammalian faunas for most of the Cenozoic Era. Terror birds and bathornithids occupied carnivorous guilds alongside predatory mammals, and ratites are still fairly successful as mid-sized herbivores; eogruiids similarly lasted from the Eocene to Pliocene, becoming extinct only very recently after over 20 million years of co-existence with many mammal groups.",
"title": "Evolutionary history"
},
{
"paragraph_id": 36,
"text": "Dinosaurs belong to a group known as archosaurs, which also includes modern crocodilians. Within the archosaur group, dinosaurs are differentiated most noticeably by their gait. Dinosaur legs extend directly beneath the body, whereas the legs of lizards and crocodilians sprawl out to either side.",
"title": "Classification"
},
{
"paragraph_id": 37,
"text": "Collectively, dinosaurs as a clade are divided into two primary branches, Saurischia and Ornithischia. Saurischia includes those taxa sharing a more recent common ancestor with birds than with Ornithischia, while Ornithischia includes all taxa sharing a more recent common ancestor with Triceratops than with Saurischia. Anatomically, these two groups can be distinguished most noticeably by their pelvic structure. Early saurischians—\"lizard-hipped\", from the Greek sauros (σαῦρος) meaning \"lizard\" and ischion (ἰσχίον) meaning \"hip joint\"—retained the hip structure of their ancestors, with a pubis bone directed cranially, or forward. This basic form was modified by rotating the pubis backward to varying degrees in several groups (Herrerasaurus, therizinosauroids, dromaeosaurids, and birds). Saurischia includes the theropods (exclusively bipedal and with a wide variety of diets) and sauropodomorphs (long-necked herbivores which include advanced, quadrupedal groups).",
"title": "Classification"
},
{
"paragraph_id": 38,
"text": "By contrast, ornithischians—\"bird-hipped\", from the Greek ornitheios (ὀρνίθειος) meaning \"of a bird\" and ischion (ἰσχίον) meaning \"hip joint\"—had a pelvis that superficially resembled a bird's pelvis: the pubic bone was oriented caudally (rear-pointing). Unlike birds, the ornithischian pubis also usually had an additional forward-pointing process. Ornithischia includes a variety of species that were primarily herbivores.",
"title": "Classification"
},
{
"paragraph_id": 39,
"text": "Despite the terms \"bird hip\" (Ornithischia) and \"lizard hip\" (Saurischia), birds are not part of Ornithischia. Birds instead belong to Saurischia, the \"lizard-hipped\" dinosaurs—birds evolved from earlier dinosaurs with \"lizard hips\".",
"title": "Classification"
},
{
"paragraph_id": 40,
"text": "The following is a simplified classification of dinosaur groups based on their evolutionary relationships, and those of the main dinosaur groups Theropoda, Sauropodomorpha and Ornithischia, compiled by Justin Tweet. Further details and other hypotheses of classification may be found on individual articles.",
"title": "Classification"
},
{
"paragraph_id": 41,
"text": "Timeline of major dinosaur groups per Holtz (2007).",
"title": "Classification"
},
{
"paragraph_id": 42,
"text": "Knowledge about dinosaurs is derived from a variety of fossil and non-fossil records, including fossilized bones, feces, trackways, gastroliths, feathers, impressions of skin, internal organs and other soft tissues. Many fields of study contribute to our understanding of dinosaurs, including physics (especially biomechanics), chemistry, biology, and the Earth sciences (of which paleontology is a sub-discipline). Two topics of particular interest and study have been dinosaur size and behavior.",
"title": "Paleobiology"
},
{
"paragraph_id": 43,
"text": "Current evidence suggests that dinosaur average size varied through the Triassic, Early Jurassic, Late Jurassic and Cretaceous. Predatory theropod dinosaurs, which occupied most terrestrial carnivore niches during the Mesozoic, most often fall into the 100 to 1000 kg (220 to 2200 lb) category when sorted by estimated weight into categories based on order of magnitude, whereas recent predatory carnivoran mammals peak in the 10 to 100 kg (22 to 220 lb) category. The mode of Mesozoic dinosaur body masses is between 1 and 10 metric tons (1.1 and 11.0 short tons). This contrasts sharply with the average size of Cenozoic mammals, estimated by the National Museum of Natural History as about 2 to 5 kg (4.4 to 11.0 lb).",
"title": "Paleobiology"
},
{
"paragraph_id": 44,
"text": "The sauropods were the largest and heaviest dinosaurs. For much of the dinosaur era, the smallest sauropods were larger than anything else in their habitat, and the largest was an order of magnitude more massive than anything else that has since walked the Earth. Giant prehistoric mammals such as Paraceratherium (the largest land mammal ever) were dwarfed by the giant sauropods, and only modern whales approach or surpass them in size. There are several proposed advantages for the large size of sauropods, including protection from predation, reduction of energy use, and longevity, but it may be that the most important advantage was dietary. Large animals are more efficient at digestion than small animals, because food spends more time in their digestive systems. This also permits them to subsist on food with lower nutritive value than smaller animals. Sauropod remains are mostly found in rock formations interpreted as dry or seasonally dry, and the ability to eat large quantities of low-nutrient browse would have been advantageous in such environments.",
"title": "Paleobiology"
},
{
"paragraph_id": 45,
"text": "Scientists will probably never be certain of the largest and smallest dinosaurs to have ever existed. This is because only a tiny percentage of animals were ever fossilized and most of these remain buried in the earth. Few of the specimens that are recovered are complete skeletons, and impressions of skin and other soft tissues are rare. Rebuilding a complete skeleton by comparing the size and morphology of bones to those of similar, better-known species is an inexact art, and reconstructing the muscles and other organs of the living animal is, at best, a process of educated guesswork.",
"title": "Paleobiology"
},
{
"paragraph_id": 46,
"text": "The tallest and heaviest dinosaur known from good skeletons is Giraffatitan brancai (previously classified as a species of Brachiosaurus). Its remains were discovered in Tanzania between 1907 and 1912. Bones from several similar-sized individuals were incorporated into the skeleton now mounted and on display at the Museum für Naturkunde in Berlin; this mount is 12 meters (39 ft) tall and 21.8 to 22.5 meters (72 to 74 ft) long, and would have belonged to an animal that weighed between 30000 and 60000 kilograms (70000 and 130000 lb). The longest complete dinosaur is the 27 meters (89 ft) long Diplodocus, which was discovered in Wyoming in the United States and displayed in Pittsburgh's Carnegie Museum of Natural History in 1907. The longest dinosaur known from good fossil material is Patagotitan: the skeleton mount in the American Museum of Natural History in New York is 37 meters (121 ft) long. The Museo Municipal Carmen Funes in Plaza Huincul, Argentina, has an Argentinosaurus reconstructed skeleton mount that is 39.7 meters (130 ft) long.",
"title": "Paleobiology"
},
{
"paragraph_id": 47,
"text": "There were larger dinosaurs, but knowledge of them is based entirely on a small number of fragmentary fossils. Most of the largest herbivorous specimens on record were discovered in the 1970s or later, and include the massive Argentinosaurus, which may have weighed 80000 to 100000 kilograms (90 to 110 short tons) and reached lengths of 30 to 40 meters (98 to 131 ft); some of the longest were the 33.5-meter (110 ft) long Diplodocus hallorum (formerly Seismosaurus), the 33-to-34-meter (108 to 112 ft) long Supersaurus, and 37-meter (121 ft) long Patagotitan; and the tallest, the 18-meter (59 ft) tall Sauroposeidon, which could have reached a sixth-floor window. There were a few dinosaurs that was considered either the heaviest and longest. The most famous one include Amphicoelias fragillimus, known only from a now lost partial vertebral neural arch described in 1878. Extrapolating from the illustration of this bone, the animal may have been 58 meters (190 ft) long and weighed 122400 kg (270000 lb). However, recent research have placed Amphicoelias from the long, gracile diplodocid to the shorter but much stockier rebbachisaurid. Now renamed as Maraapunisaurus, this sauropod now stands as much as 40 meters (130 ft) long and weigh as much as 120000 kg (264555 lb). Another contender of this title includes Bruhathkayosaurus matleyi, a incredibly controversial taxon that was recently confirmed to exist after archived photos were uncovered. Bruhathkayosaurus was a titanosaur and would have most likely weighed more than even Marrapunisaurus. Recent size estimates in 2023 have placed this sauropod reaching lengths of up to 44.1 m (145 ft) long and a colossal weight range of around 110000-170000 kg (242508-374785 lb), if these upper estimates up true, Bruhathkayosaurus would have rivaled the blue whale and Perucetus colossus as one of the largest animals to have ever existed.",
"title": "Paleobiology"
},
{
"paragraph_id": 48,
"text": "The largest carnivorous dinosaur was Spinosaurus, reaching a length of 12.6 to 18 meters (41 to 59 ft), and weighing 7 to 20.9 metric tons (7.7 to 23.0 short tons). Other large carnivorous theropods included Giganotosaurus, Carcharodontosaurus and Tyrannosaurus. Therizinosaurus and Deinocheirus were among the tallest of the theropods. The largest ornithischian dinosaur was probably the hadrosaurid Shantungosaurus giganteus which measured 16.6 meters (54 ft). The largest individuals may have weighed as much as 16 metric tons (18 short tons).",
"title": "Paleobiology"
},
{
"paragraph_id": 49,
"text": "The smallest dinosaur known is the bee hummingbird, with a length of only 5 centimeters (2.0 in) and mass of around 1.8 g (0.063 oz). The smallest known non-avialan dinosaurs were about the size of pigeons and were those theropods most closely related to birds. For example, Anchiornis huxleyi is currently the smallest non-avialan dinosaur described from an adult specimen, with an estimated weight of 110 g (3.9 oz) and a total skeletal length of 34 centimeters (1.12 ft). The smallest herbivorous non-avialan dinosaurs included Microceratus and Wannanosaurus, at about 60 centimeters (2.0 ft) long each.",
"title": "Paleobiology"
},
{
"paragraph_id": 50,
"text": "Many modern birds are highly social, often found living in flocks. There is general agreement that some behaviors that are common in birds, as well as in crocodiles (closest living relatives of birds), were also common among extinct dinosaur groups. Interpretations of behavior in fossil species are generally based on the pose of skeletons and their habitat, computer simulations of their biomechanics, and comparisons with modern animals in similar ecological niches.",
"title": "Paleobiology"
},
{
"paragraph_id": 51,
"text": "The first potential evidence for herding or flocking as a widespread behavior common to many dinosaur groups in addition to birds was the 1878 discovery of 31 Iguanodon, ornithischians that were then thought to have perished together in Bernissart, Belgium, after they fell into a deep, flooded sinkhole and drowned. Other mass-death sites have been discovered subsequently. Those, along with multiple trackways, suggest that gregarious behavior was common in many early dinosaur species. Trackways of hundreds or even thousands of herbivores indicate that duck-billed (hadrosaurids) may have moved in great herds, like the American bison or the African springbok. Sauropod tracks document that these animals traveled in groups composed of several different species, at least in Oxfordshire, England, although there is no evidence for specific herd structures. Congregating into herds may have evolved for defense, for migratory purposes, or to provide protection for young. There is evidence that many types of slow-growing dinosaurs, including various theropods, sauropods, ankylosaurians, ornithopods, and ceratopsians, formed aggregations of immature individuals. One example is a site in Inner Mongolia that has yielded remains of over 20 Sinornithomimus, from one to seven years old. This assemblage is interpreted as a social group that was trapped in mud. The interpretation of dinosaurs as gregarious has also extended to depicting carnivorous theropods as pack hunters working together to bring down large prey. However, this lifestyle is uncommon among modern birds, crocodiles, and other reptiles, and the taphonomic evidence suggesting mammal-like pack hunting in such theropods as Deinonychus and Allosaurus can also be interpreted as the results of fatal disputes between feeding animals, as is seen in many modern diapsid predators.",
"title": "Paleobiology"
},
{
"paragraph_id": 52,
"text": "The crests and frills of some dinosaurs, like the marginocephalians, theropods and lambeosaurines, may have been too fragile to be used for active defense, and so they were likely used for sexual or aggressive displays, though little is known about dinosaur mating and territorialism. Head wounds from bites suggest that theropods, at least, engaged in active aggressive confrontations.",
"title": "Paleobiology"
},
{
"paragraph_id": 53,
"text": "From a behavioral standpoint, one of the most valuable dinosaur fossils was discovered in the Gobi Desert in 1971. It included a Velociraptor attacking a Protoceratops, providing evidence that dinosaurs did indeed attack each other. Additional evidence for attacking live prey is the partially healed tail of an Edmontosaurus, a hadrosaurid dinosaur; the tail is damaged in such a way that shows the animal was bitten by a tyrannosaur but survived. Cannibalism amongst some species of dinosaurs was confirmed by tooth marks found in Madagascar in 2003, involving the theropod Majungasaurus.",
"title": "Paleobiology"
},
{
"paragraph_id": 54,
"text": "Comparisons between the scleral rings of dinosaurs and modern birds and reptiles have been used to infer daily activity patterns of dinosaurs. Although it has been suggested that most dinosaurs were active during the day, these comparisons have shown that small predatory dinosaurs such as dromaeosaurids, Juravenator, and Megapnosaurus were likely nocturnal. Large and medium-sized herbivorous and omnivorous dinosaurs such as ceratopsians, sauropodomorphs, hadrosaurids, ornithomimosaurs may have been cathemeral, active during short intervals throughout the day, although the small ornithischian Agilisaurus was inferred to be diurnal.",
"title": "Paleobiology"
},
{
"paragraph_id": 55,
"text": "Based on fossil evidence from dinosaurs such as Oryctodromeus, some ornithischian species seem to have led a partially fossorial (burrowing) lifestyle. Many modern birds are arboreal (tree climbing), and this was also true of many Mesozoic birds, especially the enantiornithines. While some early bird-like species may have already been arboreal as well (including dromaeosaurids) such as Microraptor) most non-avialan dinosaurs seem to have relied on land-based locomotion. A good understanding of how dinosaurs moved on the ground is key to models of dinosaur behavior; the science of biomechanics, pioneered by Robert McNeill Alexander, has provided significant insight in this area. For example, studies of the forces exerted by muscles and gravity on dinosaurs' skeletal structure have investigated how fast dinosaurs could run, whether diplodocids could create sonic booms via whip-like tail snapping, and whether sauropods could float.",
"title": "Paleobiology"
},
{
"paragraph_id": 56,
"text": "Modern birds are known to communicate using visual and auditory signals, and the wide diversity of visual display structures among fossil dinosaur groups, such as horns, frills, crests, sails, and feathers, suggests that visual communication has always been important in dinosaur biology. Reconstruction of the plumage color of Anchiornis, suggest the importance of color in visual communication in non-avian dinosaurs. Vocalization in non-avian dinosaurs is less certain. In birds, the larynx plays no role in sound production. Instead they vocalize with a novel organ called the syrinx, located further down the trachea. The earliest remains of a syrinx was found in a specimen of the duck-like Vegavis iaai dated 69 –66 million years ago, and this organ is unlikely to have existed in non-avian dinosaurs.",
"title": "Paleobiology"
},
{
"paragraph_id": 57,
"text": "Paleontologist Phil Senter has suggested that since non-avian dinosaurs did not have a syrinx, and their next closest living relatives, crocodilians, use the larynx, they could not vocalize as the common ancestor would have been mute. He states that they mostly on visual displays and possibly non-vocal acoustic sounds like hissing, jaw grinding or clapping, splashing and wing beating (possible in winged maniraptoran dinosaurs). Other researchers have countered that vocalizations also exist in turtles, the closest relatives of archosaurs, suggesting that the trait is ancestral to their lineage. In addition, vocal communication in dinosaurs is indicated by the development of advanced hearing in nearly all major groups. Hence the syrinx may have supplemented and then replaced the larynx as a vocal organ rather than there being a \"silent period\" in bird evolution.",
"title": "Paleobiology"
},
{
"paragraph_id": 58,
"text": "In 2023, a fossilized larynx was described from a specimen of the ankylosaurid Pinacosaurus. The structure was composed of cricoid and arytenoid cartilages, similar to those of non-avian reptiles. However, the mobile cricoid-arytenoid joint and long arytenoid cartilages would have allowed for air-flow control similar to that of birds, and thus could have made bird-like vocalizations. In addition, the cartilages were ossified, implying that laryngeal ossification is a feature of some non-avian dinosaurs. A 2016 study concludes that some dinosaurs may have produced closed mouth vocalizations like cooing, hooting and booming. These occur in both reptiles and birds and involve inflating the esophagus or tracheal pouches. Such vocalizations evolved independently in extant archosaurs numerous times, following increases in body size. The crests of some hadrosaurids and the nasal chambers of ankylosaurids have been suggested to have functioned in acoustic resonance.",
"title": "Paleobiology"
},
{
"paragraph_id": 59,
"text": "All dinosaurs laid amniotic eggs. Dinosaur eggs were usually laid in a nest. Most species create somewhat elaborate nests which can be cups, domes, plates, beds scrapes, mounds, or burrows. Some species of modern bird have no nests; the cliff-nesting common guillemot lays its eggs on bare rock, and male emperor penguins keep eggs between their body and feet. Primitive birds and many non-avialan dinosaurs often lay eggs in communal nests, with males primarily incubating the eggs. While modern birds have only one functional oviduct and lay one egg at a time, more primitive birds and dinosaurs had two oviducts, like crocodiles. Some non-avialan dinosaurs, such as Troodon, exhibited iterative laying, where the adult might lay a pair of eggs every one or two days, and then ensured simultaneous hatching by delaying brooding until all eggs were laid.",
"title": "Paleobiology"
},
{
"paragraph_id": 60,
"text": "When laying eggs, females grow a special type of bone between the hard outer bone and the marrow of their limbs. This medullary bone, which is rich in calcium, is used to make eggshells. A discovery of features in a Tyrannosaurus skeleton provided evidence of medullary bone in extinct dinosaurs and, for the first time, allowed paleontologists to establish the sex of a fossil dinosaur specimen. Further research has found medullary bone in the carnosaur Allosaurus and the ornithopod Tenontosaurus. Because the line of dinosaurs that includes Allosaurus and Tyrannosaurus diverged from the line that led to Tenontosaurus very early in the evolution of dinosaurs, this suggests that the production of medullary tissue is a general characteristic of all dinosaurs.",
"title": "Paleobiology"
},
{
"paragraph_id": 61,
"text": "Another widespread trait among modern birds (but see below in regards to fossil groups and extant megapodes) is parental care for young after hatching. Jack Horner's 1978 discovery of a Maiasaura (\"good mother lizard\") nesting ground in Montana demonstrated that parental care continued long after birth among ornithopods. A specimen of the oviraptorid Citipati osmolskae was discovered in a chicken-like brooding position in 1993, which may indicate that they had begun using an insulating layer of feathers to keep the eggs warm. An embryo of the basal sauropodomorph Massospondylus was found without teeth, indicating that some parental care was required to feed the young dinosaurs. Trackways have also confirmed parental behavior among ornithopods from the Isle of Skye in northwestern Scotland.",
"title": "Paleobiology"
},
{
"paragraph_id": 62,
"text": "However, there is ample evidence of precociality or superprecociality among many dinosaur species, particularly theropods. For instance, non-ornithuromorph birds have been abundantly demonstrated to have had slow growth rates, megapode-like egg burying behavior and the ability to fly soon after birth. Both Tyrannosaurus and Troodon had juveniles with clear superprecociality and likely occupying different ecological niches than the adults. Superprecociality has been inferred for sauropods.",
"title": "Paleobiology"
},
{
"paragraph_id": 63,
"text": "Genital structures are unlikely to fossilize as they lack scales that may allow preservation via pigmentation or residual calcium phosphate salts. In 2021, the best preserved specimen of a dinosaur's cloacal vent exterior was described for Psittacosaurus, demonstrating lateral swellings similar to crocodylian musk glands used in social displays by both sexes and pigmented regions which could also reflect a signalling function. However, this specimen on its own does not offer enough information to determine whether this dinosaur had sexual signalling functions; it only supports the possibility. Cloacal visual signalling can occur in either males or females in living birds, making it unlikely to be useful to determine sex for extinct dinosaurs.",
"title": "Paleobiology"
},
{
"paragraph_id": 64,
"text": "Because both modern crocodilians and birds have four-chambered hearts (albeit modified in crocodilians), it is likely that this is a trait shared by all archosaurs, including all dinosaurs. While all modern birds have high metabolisms and are endothermic (\"warm-blooded\"), a vigorous debate has been ongoing since the 1960s regarding how far back in the dinosaur lineage this trait extended. Various researchers have supported dinosaurs as being endothermic, ectothermic (\"cold-blooded\"), or somewhere in between. An emerging consensus among researchers is that, while different lineages of dinosaurs would have had different metabolisms, most of them had higher metabolic rates than other reptiles but lower than living birds and mammals, which is termed mesothermy by some. Evidence from crocodiles and their extinct relatives suggests that such elevated metabolisms could have developed in the earliest archosaurs, which were the common ancestors of dinosaurs and crocodiles.",
"title": "Paleobiology"
},
{
"paragraph_id": 65,
"text": "After non-avian dinosaurs were discovered, paleontologists first posited that they were ectothermic. This was used to imply that the ancient dinosaurs were relatively slow, sluggish organisms, even though many modern reptiles are fast and light-footed despite relying on external sources of heat to regulate their body temperature. The idea of dinosaurs as ectothermic remained a prevalent view until Robert T. Bakker, an early proponent of dinosaur endothermy, published an influential paper on the topic in 1968. Bakker specifically used anatomical and ecological evidence to argue that sauropods, which had hitherto been depicted as sprawling aquatic animals with their tails dragging on the ground, were endotherms that lived vigorous, terrestrial lives. In 1972, Bakker expanded on his arguments based on energy requirements and predator-prey ratios. This was one of the seminal results that led to the dinosaur renaissance.",
"title": "Paleobiology"
},
{
"paragraph_id": 66,
"text": "One of the greatest contributions to the modern understanding of dinosaur physiology has been paleohistology, the study of microscopic tissue structure in dinosaurs. From the 1960s forward, Armand de Ricqlès suggested that the presence of fibrolamellar bone—bony tissue with an irregular, fibrous texture and filled with blood vessels—was indicative of consistently fast growth and therefore endothermy. Fibrolamellar bone was common in both dinosaurs and pterosaurs, though not universally present. This has led to a significant body of work in reconstructing growth curves and modeling the evolution of growth rates across various dinosaur lineages, which has suggested overall that dinosaurs grew faster than living reptiles. Other lines of evidence suggesting endothermy include the presence of feathers and other types of body coverings in many lineages (see § Feathers); more consistent ratios of the isotope oxygen-18 in bony tissue compared to ectotherms, particularly as latitude and thus air temperature varied, which suggests stable internal temperatures (although these ratios can be altered during fossilization); and the discovery of polar dinosaurs, which lived in Australia, Antarctica, and Alaska when these places would have had cool, temperate climates.",
"title": "Paleobiology"
},
{
"paragraph_id": 67,
"text": "In saurischian dinosaurs, higher metabolisms were supported by the evolution of the avian respiratory system, characterized by an extensive system of air sacs that extended the lungs and invaded many of the bones in the skeleton, making them hollow. Such respiratory systems, which may have appeared in the earliest saurischians, would have provided them with more oxygen compared to a mammal of similar size, while also having a larger resting tidal volume and requiring a lower breathing frequency, which would have allowed them to sustain higher activity levels. The rapid airflow would also have been an effective cooling mechanism, which in conjunction with a lower metabolic rate would have prevented large sauropods from overheating. These traits may have enabled sauropods to grow quickly to gigantic sizes. Sauropods may also have benefitted from their size—their small surface area to volume ratio meant that they would have been able to thermoregulate more easily, a phenomenon termed gigantothermy.",
"title": "Paleobiology"
},
{
"paragraph_id": 68,
"text": "Like other reptiles, dinosaurs are primarily uricotelic, that is, their kidneys extract nitrogenous wastes from their bloodstream and excrete it as uric acid instead of urea or ammonia via the ureters into the intestine. This would have helped them to conserve water. In most living species, uric acid is excreted along with feces as a semisolid waste. However, at least some modern birds (such as hummingbirds) can be facultatively ammonotelic, excreting most of the nitrogenous wastes as ammonia. This material, as well as the output of the intestines, emerges from the cloaca. In addition, many species regurgitate pellets, and fossil pellets are known as early as the Jurassic from Anchiornis.",
"title": "Paleobiology"
},
{
"paragraph_id": 69,
"text": "The size and shape of the brain can be partly reconstructed based on the surrounding bones. In 1896, Marsh calculated ratios between brain weight and body weight of seven species of dinosaurs, showing that the brain of dinosaurs was proportionally smaller than in today's crocodiles, and that the brain of Stegosaurus was smaller than in any living land vertebrate. This contributed to the widespread public notion of dinosaurs as being sluggish and extraordinarily stupid. Harry Jerison, in 1973, showed that proportionally smaller brains are expected at larger body sizes, and that brain size in dinosaurs was not smaller than expected when compared to living reptiles. Later research showed that relative brain size progressively increased during the evolution of theropods, with the highest intelligence – comparable to that of modern birds – calculated for the troodontid Troodon.",
"title": "Paleobiology"
},
{
"paragraph_id": 70,
"text": "The possibility that dinosaurs were the ancestors of birds was first suggested in 1868 by Thomas Henry Huxley. After the work of Gerhard Heilmann in the early 20th century, the theory of birds as dinosaur descendants was abandoned in favor of the idea of them being descendants of generalized thecodonts, with the key piece of evidence being the supposed lack of clavicles in dinosaurs. However, as later discoveries showed, clavicles (or a single fused wishbone, which derived from separate clavicles) were not actually absent; they had been found as early as 1924 in Oviraptor, but misidentified as an interclavicle. In the 1970s, Ostrom revived the dinosaur–bird theory, which gained momentum in the coming decades with the advent of cladistic analysis, and a great increase in the discovery of small theropods and early birds. Of particular note have been the fossils of the Jehol Biota, where a variety of theropods and early birds have been found, often with feathers of some type. Birds share over a hundred distinct anatomical features with theropod dinosaurs, which are now generally accepted to have been their closest ancient relatives. They are most closely allied with maniraptoran coelurosaurs. A minority of scientists, most notably Alan Feduccia and Larry Martin, have proposed other evolutionary paths, including revised versions of Heilmann's basal archosaur proposal, or that maniraptoran theropods are the ancestors of birds but themselves are not dinosaurs, only convergent with dinosaurs.",
"title": "Origin of birds"
},
{
"paragraph_id": 71,
"text": "Feathers are one of the most recognizable characteristics of modern birds, and a trait that was also shared by several non-avian dinosaurs. Based on the current distribution of fossil evidence, it appears that feathers were an ancestral dinosaurian trait, though one that may have been selectively lost in some species. Direct fossil evidence of feathers or feather-like structures has been discovered in a diverse array of species in many non-avian dinosaur groups, both among saurischians and ornithischians. Simple, branched, feather-like structures are known from heterodontosaurids, primitive neornithischians, and theropods, and primitive ceratopsians. Evidence for true, vaned feathers similar to the flight feathers of modern birds has been found only in the theropod subgroup Maniraptora, which includes oviraptorosaurs, troodontids, dromaeosaurids, and birds. Feather-like structures known as pycnofibres have also been found in pterosaurs.",
"title": "Origin of birds"
},
{
"paragraph_id": 72,
"text": "However, researchers do not agree regarding whether these structures share a common origin between lineages (i.e., they are homologous), or if they were the result of widespread experimentation with skin coverings among ornithodirans. If the former is the case, filaments may have been common in the ornithodiran lineage and evolved before the appearance of dinosaurs themselves. Research into the genetics of American alligators has revealed that crocodylian scutes do possess feather-keratins during embryonic development, but these keratins are not expressed by the animals before hatching. The description of feathered dinosaurs has not been without controversy in general; perhaps the most vocal critics have been Alan Feduccia and Theagarten Lingham-Soliar, who have proposed that some purported feather-like fossils are the result of the decomposition of collagenous fiber that underlaid the dinosaurs' skin, and that maniraptoran dinosaurs with vaned feathers were not actually dinosaurs, but convergent with dinosaurs. However, their views have for the most part not been accepted by other researchers, to the point that the scientific nature of Feduccia's proposals has been questioned.",
"title": "Origin of birds"
},
{
"paragraph_id": 73,
"text": "Archaeopteryx was the first fossil found that revealed a potential connection between dinosaurs and birds. It is considered a transitional fossil, in that it displays features of both groups. Brought to light just two years after Charles Darwin's seminal On the Origin of Species (1859), its discovery spurred the nascent debate between proponents of evolutionary biology and creationism. This early bird is so dinosaur-like that, without a clear impression of feathers in the surrounding rock, at least one specimen was mistaken for the small theropod Compsognathus. Since the 1990s, a number of additional feathered dinosaurs have been found, providing even stronger evidence of the close relationship between dinosaurs and modern birds. Many of these specimens were unearthed in the lagerstätten of the Jehol Biota. If feather-like structures were indeed widely present among non-avian dinosaurs, the lack of abundant fossil evidence for them may be due to the fact that delicate features like skin and feathers are seldom preserved by fossilization and thus often absent from the fossil record.",
"title": "Origin of birds"
},
{
"paragraph_id": 74,
"text": "Because feathers are often associated with birds, feathered dinosaurs are often touted as the missing link between birds and dinosaurs. However, the multiple skeletal features also shared by the two groups represent another important line of evidence for paleontologists. Areas of the skeleton with important similarities include the neck, pubis, wrist (semi-lunate carpal), arm and pectoral girdle, furcula (wishbone), and breast bone. Comparison of bird and dinosaur skeletons through cladistic analysis strengthens the case for the link.",
"title": "Origin of birds"
},
{
"paragraph_id": 75,
"text": "Large meat-eating dinosaurs had a complex system of air sacs similar to those found in modern birds, according to a 2005 investigation led by Patrick M. O'Connor. The lungs of theropod dinosaurs (carnivores that walked on two legs and had bird-like feet) likely pumped air into hollow sacs in their skeletons, as is the case in birds. \"What was once formally considered unique to birds was present in some form in the ancestors of birds\", O'Connor said. In 2008, scientists described Aerosteon riocoloradensis, the skeleton of which supplies the strongest evidence to date of a dinosaur with a bird-like breathing system. CT scanning of Aerosteon's fossil bones revealed evidence for the existence of air sacs within the animal's body cavity.",
"title": "Origin of birds"
},
{
"paragraph_id": 76,
"text": "Fossils of the troodonts Mei and Sinornithoides demonstrate that some dinosaurs slept with their heads tucked under their arms. This behavior, which may have helped to keep the head warm, is also characteristic of modern birds. Several deinonychosaur and oviraptorosaur specimens have also been found preserved on top of their nests, likely brooding in a bird-like manner. The ratio between egg volume and body mass of adults among these dinosaurs suggest that the eggs were primarily brooded by the male, and that the young were highly precocial, similar to many modern ground-dwelling birds.",
"title": "Origin of birds"
},
{
"paragraph_id": 77,
"text": "Some dinosaurs are known to have used gizzard stones like modern birds. These stones are swallowed by animals to aid digestion and break down food and hard fibers once they enter the stomach. When found in association with fossils, gizzard stones are called gastroliths.",
"title": "Origin of birds"
},
{
"paragraph_id": 78,
"text": "All non-avian dinosaurs and most lineages of birds became extinct in a mass extinction event, called the Cretaceous–Paleogene (K-Pg) extinction event, at the end of the Cretaceous period. Above the Cretaceous–Paleogene boundary, which has been dated to 66.038 ± 0.025 million years ago, fossils of non-avian dinosaurs disappear abruptly; the absence of dinosaur fossils was historically used to assign rocks to the ensuing Cenozoic. The nature of the event that caused this mass extinction has been extensively studied since the 1970s, leading to the development of two mechanisms that are thought to have played major roles: an extraterrestrial impact event in the Yucatán Peninsula, along with flood basalt volcanism in India. However, the specific mechanisms of the extinction event and the extent of its effects on dinosaurs are still areas of ongoing research. Alongside dinosaurs, many other groups of animals became extinct: pterosaurs, marine reptiles such as mosasaurs and plesiosaurs, several groups of mammals, ammonites (nautilus-like mollusks), rudists (reef-building bivalves), and various groups of marine plankton. In all, approximately 47% of genera and 76% of species on Earth became extinct during the K-Pg extinction event. The relatively large size of most dinosaurs and the low diversity of small-bodied dinosaur species at the end of the Cretaceous may have contributed to their extinction; the extinction of the bird lineages that did not survive may also have been caused by a dependence on forest habitats or a lack of adaptations to eating seeds for survival.",
"title": "Extinction of major groups"
},
{
"paragraph_id": 79,
"text": "Just before the K-Pg extinction event, the number of non-avian dinosaur species that existed globally has been estimated at between 628 and 1078. It remains uncertain whether the diversity of dinosaurs was in gradual decline before the K-Pg extinction event, or whether dinosaurs were actually thriving prior to the extinction. Rock formations from the Maastrichtian epoch, which directly preceded the extinction, have been found to have lower diversity than the preceding Campanian epoch, which led to the prevailing view of a long-term decline in diversity. However, these comparisons did not account either for varying preservation potential between rock units or for different extents of exploration and excavation. In 1984, Dale Russell carried out an analysis to account for these biases, and found no evidence of a decline; another analysis by David Fastovsky and colleagues in 2004 even showed that dinosaur diversity continually increased until the extinction, but this analysis has been rebutted. Since then, different approaches based on statistics and mathematical models have variously supported either a sudden extinction or a gradual decline. End-Cretaceous trends in diversity may have varied between dinosaur lineages: it has been suggested that sauropods were not in decline, while ornithischians and theropods were in decline.",
"title": "Extinction of major groups"
},
{
"paragraph_id": 80,
"text": "The bolide impact hypothesis, first brought to wide attention in 1980 by Walter Alvarez, Luis Alvarez, and colleagues, attributes the K-Pg extinction event to a bolide (extraterrestrial projectile) impact. Alvarez and colleagues proposed that a sudden increase in iridium levels, recorded around the world in rock deposits at the Cretaceous–Paleogene boundary, was direct evidence of the impact. Shocked quartz, indicative of a strong shockwave emanating from an impact, was also found worldwide. The actual impact site remained elusive until a crater measuring 180 km (110 mi) wide was discovered in the Yucatán Peninsula of southeastern Mexico, and was publicized in a 1991 paper by Alan Hildebrand and colleagues. Now, the bulk of the evidence suggests that a bolide 5 to 15 kilometers (3 to 9+1⁄2 miles) wide impacted the Yucatán Peninsula 66 million years ago, forming this crater and creating a \"kill mechanism\" that triggered the extinction event.",
"title": "Extinction of major groups"
},
{
"paragraph_id": 81,
"text": "Within hours, the Chicxulub impact would have created immediate effects such as earthquakes, tsunamis, and a global firestorm that likely killed unsheltered animals and started wildfires. However, it would also have had longer-term consequences for the environment. Within days, sulfate aerosols released from rocks at the impact site would have contributed to acid rain and ocean acidification. Soot aerosols are thought to have spread around the world over the ensuing months and years; they would have cooled the surface of the Earth by reflecting thermal radiation, and greatly slowed photosynthesis by blocking out sunlight, thus creating an impact winter. (This role was ascribed to sulfate aerosols until experiments demonstrated otherwise.) The cessation of photosynthesis would have led to the collapse of food webs depending on leafy plants, which included all dinosaurs save for grain-eating birds.",
"title": "Extinction of major groups"
},
{
"paragraph_id": 82,
"text": "At the time of the K-Pg extinction, the Deccan Traps flood basalts of India were actively erupting. The eruptions can be separated into three phases around the K-Pg boundary, two prior to the boundary and one after. The second phase, which occurred very close to the boundary, would have extruded 70 to 80% of the volume of these eruptions in intermittent pulses that occurred around 100,000 years apart. Greenhouse gases such as carbon dioxide and sulfur dioxide would have been released by this volcanic activity, resulting in climate change through temperature perturbations of roughly 3 °C (5.4 °F) but possibly as high as 7 °C (13 °F). Like the Chicxulub impact, the eruptions may also have released sulfate aerosols, which would have caused acid rain and global cooling. However, due to large error margins in the dating of the eruptions, the role of the Deccan Traps in the K-Pg extinction remains unclear.",
"title": "Extinction of major groups"
},
{
"paragraph_id": 83,
"text": "Before 2000, arguments that the Deccan Traps eruptions—as opposed to the Chicxulub impact—caused the extinction were usually linked to the view that the extinction was gradual. Prior to the discovery of the Chicxulub crater, the Deccan Traps were used to explain the global iridium layer; even after the crater's discovery, the impact was still thought to only have had a regional, not global, effect on the extinction event. In response, Luis Alvarez rejected volcanic activity as an explanation for the iridium layer and the extinction as a whole. Since then, however, most researchers have adopted a more moderate position, which identifies the Chicxulub impact as the primary progenitor of the extinction while also recognizing that the Deccan Traps may also have played a role. Walter Alvarez himself has acknowledged that the Deccan Traps and other ecological factors may have contributed to the extinctions in addition to the Chicxulub impact. Some estimates have placed the start of the second phase in the Deccan Traps eruptions within 50,000 years after the Chicxulub impact. Combined with mathematical modelling of the seismic waves that would have been generated by the impact, this has led to the suggestion that the Chicxulub impact may have triggered these eruptions by increasing the permeability of the mantle plume underlying the Deccan Traps.",
"title": "Extinction of major groups"
},
{
"paragraph_id": 84,
"text": "Whether the Deccan Traps were a major cause of the extinction, on par with the Chicxulub impact, remains uncertain. Proponents consider the climatic impact of the sulfur dioxide released to have been on par with the Chicxulub impact, and also note the role of flood basalt volcanism in other mass extinctions like the Permian-Triassic extinction event. They consider the Chicxulub impact to have worsened the ongoing climate change caused by the eruptions. Meanwhile, detractors point out the sudden nature of the extinction and that other pulses in Deccan Traps activity of comparable magnitude did not appear to have caused extinctions. They also contend that the causes of different mass extinctions should be assessed separately. In 2020, Alfio Chiarenza and colleagues suggested that the Deccan Traps may even have had the opposite effect: they suggested that the long-term warming caused by its carbon dioxide emissions may have dampened the impact winter from the Chicxulub impact.",
"title": "Extinction of major groups"
},
{
"paragraph_id": 85,
"text": "Non-avian dinosaur remains have occasionally been found above the K-Pg boundary. In 2000, Spencer Lucas and colleagues reported the discovery of a single hadrosaur right femur in the San Juan Basin of New Mexico, and described it as evidence of Paleocene dinosaurs. The rock unit in which the bone was discovered has been dated to the early Paleocene epoch, approximately 64.8 million years ago. If the bone was not re-deposited by weathering action, it would provide evidence that some dinosaur populations survived at least half a million years into the Cenozoic. Other evidence includes the presence of dinosaur remains in the Hell Creek Formation up to 1.3 m (4.3 ft) above the Cretaceous–Paleogene boundary, representing 40,000 years of elapsed time. This has been used to support the view that the K-Pg extinction was gradual. However, these supposed Paleocene dinosaurs are considered by many other researchers to be reworked, that is, washed out of their original locations and then re-buried in younger sediments. The age estimates have also been considered unreliable.",
"title": "Extinction of major groups"
},
{
"paragraph_id": 86,
"text": "By human standards, dinosaurs were creatures of fantastic appearance and often enormous size. As such, they have captured the popular imagination and become an enduring part of human culture. The entry of the word \"dinosaur\" into the common vernacular reflects the animals' cultural importance: in English, \"dinosaur\" is commonly used to describe anything that is impractically large, obsolete, or bound for extinction.",
"title": "Cultural depictions"
},
{
"paragraph_id": 87,
"text": "Public enthusiasm for dinosaurs first developed in Victorian England, where in 1854, three decades after the first scientific descriptions of dinosaur remains, a menagerie of lifelike dinosaur sculptures was unveiled in London's Crystal Palace Park. The Crystal Palace dinosaurs proved so popular that a strong market in smaller replicas soon developed. In subsequent decades, dinosaur exhibits opened at parks and museums around the world, ensuring that successive generations would be introduced to the animals in an immersive and exciting way. The enduring popularity of dinosaurs, in its turn, has resulted in significant public funding for dinosaur science, and has frequently spurred new discoveries. In the United States, for example, the competition between museums for public attention led directly to the Bone Wars of the 1880s and 1890s, during which a pair of feuding paleontologists made enormous scientific contributions.",
"title": "Cultural depictions"
},
{
"paragraph_id": 88,
"text": "The popular preoccupation with dinosaurs has ensured their appearance in literature, film, and other media. Beginning in 1852 with a passing mention in Charles Dickens' Bleak House, dinosaurs have been featured in large numbers of fictional works. Jules Verne's 1864 novel Journey to the Center of the Earth, Sir Arthur Conan Doyle's 1912 book The Lost World, the 1914 animated film Gertie the Dinosaur (featuring the first animated dinosaur), the iconic 1933 film King Kong, the 1954 Godzilla and its many sequels, the best-selling 1990 novel Jurassic Park by Michael Crichton and its 1993 film adaptation are just a few notable examples of dinosaur appearances in fiction. Authors of general-interest non-fiction works about dinosaurs, including some prominent paleontologists, have often sought to use the animals as a way to educate readers about science in general. Dinosaurs are ubiquitous in advertising; numerous companies have referenced dinosaurs in printed or televised advertisements, either in order to sell their own products or in order to characterize their rivals as slow-moving, dim-witted, or obsolete.",
"title": "Cultural depictions"
},
{
"paragraph_id": 89,
"text": "",
"title": "References"
},
{
"paragraph_id": 90,
"text": "",
"title": "References"
}
] | Dinosaurs are a diverse group of reptiles of the clade Dinosauria. They first appeared during the Triassic period, between 243 and 233.23 million years ago (mya), although the exact origin and timing of the evolution of dinosaurs is a subject of active research. They became the dominant terrestrial vertebrates after the Triassic–Jurassic extinction event 201.3 mya and their dominance continued throughout the Jurassic and Cretaceous periods. The fossil record shows that birds are feathered dinosaurs, having evolved from earlier theropods during the Late Jurassic epoch, and are the only dinosaur lineage known to have survived the Cretaceous–Paleogene extinction event approximately 66 mya. Dinosaurs can therefore be divided into avian dinosaurs—birds—and the extinct non-avian dinosaurs, which are all dinosaurs other than birds. Dinosaurs are varied from taxonomic, morphological and ecological standpoints. Birds, at over 10,700 living species, are among the most diverse groups of vertebrates. Using fossil evidence, paleontologists have identified over 900 distinct genera and more than 1,000 different species of non-avian dinosaurs. Dinosaurs are represented on every continent by both extant species (birds) and fossil remains. Through the first half of the 20th century, before birds were recognized as dinosaurs, most of the scientific community believed dinosaurs to have been sluggish and cold-blooded. Most research conducted since the 1970s, however, has indicated that dinosaurs were active animals with elevated metabolisms and numerous adaptations for social interaction. Some were herbivorous, others carnivorous. Evidence suggests that all dinosaurs were egg-laying, and that nest-building was a trait shared by many dinosaurs, both avian and non-avian. While dinosaurs were ancestrally bipedal, many extinct groups included quadrupedal species, and some were able to shift between these stances. Elaborate display structures such as horns or crests are common to all dinosaur groups, and some extinct groups developed skeletal modifications such as bony armor and spines. While the dinosaurs' modern-day surviving avian lineage (birds) are generally small due to the constraints of flight, many prehistoric dinosaurs were large-bodied—the largest sauropod dinosaurs are estimated to have reached lengths of 39.7 meters and heights of 18 m (59 ft) and were the largest land animals of all time. The misconception that non-avian dinosaurs were uniformly gigantic is based in part on preservation bias, as large, sturdy bones are more likely to last until they are fossilized. Many dinosaurs were quite small, some measuring about 50 centimeters in length. The first dinosaur fossils were recognized in the early 19th century, with the name "dinosaur" being coined by Sir Richard Owen in 1842 to refer to these "great fossil lizards". Since then, mounted fossil dinosaur skeletons have been major attractions at museums worldwide, and dinosaurs have become an enduring part of popular culture. The large sizes of some dinosaurs, as well as their seemingly monstrous and fantastic nature, have ensured their regular appearance in best-selling books and films, such as Jurassic Park. Persistent public enthusiasm for the animals has resulted in significant funding for dinosaur science, and new discoveries are regularly covered by the media. | 2001-11-14T06:36:04Z | 2023-12-25T03:00:26Z | [
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8,315 | Diamagnetism | Diamagnetism is the property of materials that are repelled by a magnetic field; an applied magnetic field creates an induced magnetic field in them in the opposite direction, causing a repulsive force. In contrast, paramagnetic and ferromagnetic materials are attracted by a magnetic field. Diamagnetism is a quantum mechanical effect that occurs in all materials; when it is the only contribution to the magnetism, the material is called diamagnetic. In paramagnetic and ferromagnetic substances, the weak diamagnetic force is overcome by the attractive force of magnetic dipoles in the material. The magnetic permeability of diamagnetic materials is less than the permeability of vacuum, μ0. In most materials, diamagnetism is a weak effect which can be detected only by sensitive laboratory instruments, but a superconductor acts as a strong diamagnet because it entirely expels any magnetic field from its interior (the Meissner effect).
Diamagnetism was first discovered when Anton Brugmans observed in 1778 that bismuth was repelled by magnetic fields. In 1845, Michael Faraday demonstrated that it was a property of matter and concluded that every material responded (in either a diamagnetic or paramagnetic way) to an applied magnetic field. On a suggestion by William Whewell, Faraday first referred to the phenomenon as diamagnetic (the prefix dia- meaning through or across), then later changed it to diamagnetism.
A simple rule of thumb is used in chemistry to determine whether a particle (atom, ion, or molecule) is paramagnetic or diamagnetic: If all electrons in the particle are paired, then the substance made of this particle is diamagnetic; If it has unpaired electrons, then the substance is paramagnetic.
Diamagnetism is a property of all materials, and always makes a weak contribution to the material's response to a magnetic field. However, other forms of magnetism (such as ferromagnetism or paramagnetism) are so much stronger such that, when different forms of magnetism are present in a material, the diamagnetic contribution is usually negligible. Substances where the diamagnetic behaviour is the strongest effect are termed diamagnetic materials, or diamagnets. Diamagnetic materials are those that some people generally think of as non-magnetic, and include water, wood, most organic compounds such as petroleum and some plastics, and many metals including copper, particularly the heavy ones with many core electrons, such as mercury, gold and bismuth. The magnetic susceptibility values of various molecular fragments are called Pascal's constants (named after Paul Pascal [fr]).
Diamagnetic materials, like water, or water-based materials, have a relative magnetic permeability that is less than or equal to 1, and therefore a magnetic susceptibility less than or equal to 0, since susceptibility is defined as χv = μv − 1. This means that diamagnetic materials are repelled by magnetic fields. However, since diamagnetism is such a weak property, its effects are not observable in everyday life. For example, the magnetic susceptibility of diamagnets such as water is χv = −9.05×10. The most strongly diamagnetic material is bismuth, χv = −1.66×10, although pyrolytic carbon may have a susceptibility of χv = −4.00×10 in one plane. Nevertheless, these values are orders of magnitude smaller than the magnetism exhibited by paramagnets and ferromagnets. Because χv is derived from the ratio of the internal magnetic field to the applied field, it is a dimensionless value.
In rare cases, the diamagnetic contribution can be stronger than paramagnetic contribution. This is the case for gold, which has a magnetic susceptibility less than 0 (and is thus by definition a diamagnetic material), but when measured carefully with X-ray magnetic circular dichroism, has an extremely weak paramagnetic contribution that is overcome by a stronger diamagnetic contribution.
Superconductors may be considered perfect diamagnets (χv = −1), because they expel all magnetic fields (except in a thin surface layer) due to the Meissner effect.
If a powerful magnet (such as a supermagnet) is covered with a layer of water (that is thin compared to the diameter of the magnet) then the field of the magnet significantly repels the water. This causes a slight dimple in the water's surface that may be seen by a reflection in its surface.
Diamagnets may be levitated in stable equilibrium in a magnetic field, with no power consumption. Earnshaw's theorem seems to preclude the possibility of static magnetic levitation. However, Earnshaw's theorem applies only to objects with positive susceptibilities, such as ferromagnets (which have a permanent positive moment) and paramagnets (which induce a positive moment). These are attracted to field maxima, which do not exist in free space. Diamagnets (which induce a negative moment) are attracted to field minima, and there can be a field minimum in free space.
A thin slice of pyrolytic graphite, which is an unusually strongly diamagnetic material, can be stably floated in a magnetic field, such as that from rare earth permanent magnets. This can be done with all components at room temperature, making a visually effective and relatively convenient demonstration of diamagnetism.
The Radboud University Nijmegen, the Netherlands, has conducted experiments where water and other substances were successfully levitated. Most spectacularly, a live frog (see figure) was levitated.
In September 2009, NASA's Jet Propulsion Laboratory (JPL) in Pasadena, California announced it had successfully levitated mice using a superconducting magnet, an important step forward since mice are closer biologically to humans than frogs. JPL said it hopes to perform experiments regarding the effects of microgravity on bone and muscle mass.
Recent experiments studying the growth of protein crystals have led to a technique using powerful magnets to allow growth in ways that counteract Earth's gravity.
A simple homemade device for demonstration can be constructed out of bismuth plates and a few permanent magnets that levitate a permanent magnet.
The electrons in a material generally settle in orbitals, with effectively zero resistance and act like current loops. Thus it might be imagined that diamagnetism effects in general would be common, since any applied magnetic field would generate currents in these loops that would oppose the change, in a similar way to superconductors, which are essentially perfect diamagnets. However, since the electrons are rigidly held in orbitals by the charge of the protons and are further constrained by the Pauli exclusion principle, many materials exhibit diamagnetism, but typically respond very little to the applied field.
The Bohr–Van Leeuwen theorem proves that there cannot be any diamagnetism or paramagnetism in a purely classical system. However, the classical theory of Langevin for diamagnetism gives the same prediction as the quantum theory. The classical theory is given below.
Paul Langevin's theory of diamagnetism (1905) applies to materials containing atoms with closed shells (see dielectrics). A field with intensity B, applied to an electron with charge e and mass m, gives rise to Larmor precession with frequency ω = eB / 2m. The number of revolutions per unit time is ω / 2π, so the current for an atom with Z electrons is (in SI units)
The magnetic moment of a current loop is equal to the current times the area of the loop. Suppose the field is aligned with the z axis. The average loop area can be given as π ⟨ ρ 2 ⟩ {\displaystyle \scriptstyle \pi \left\langle \rho ^{2}\right\rangle } , where ⟨ ρ 2 ⟩ {\displaystyle \scriptstyle \left\langle \rho ^{2}\right\rangle } is the mean square distance of the electrons perpendicular to the z axis. The magnetic moment is therefore
If the distribution of charge is spherically symmetric, we can suppose that the distribution of x,y,z coordinates are independent and identically distributed. Then ⟨ x 2 ⟩ = ⟨ y 2 ⟩ = ⟨ z 2 ⟩ = 1 3 ⟨ r 2 ⟩ {\displaystyle \scriptstyle \left\langle x^{2}\right\rangle \;=\;\left\langle y^{2}\right\rangle \;=\;\left\langle z^{2}\right\rangle \;=\;{\frac {1}{3}}\left\langle r^{2}\right\rangle } , where ⟨ r 2 ⟩ {\displaystyle \scriptstyle \left\langle r^{2}\right\rangle } is the mean square distance of the electrons from the nucleus. Therefore, ⟨ ρ 2 ⟩ = ⟨ x 2 ⟩ + ⟨ y 2 ⟩ = 2 3 ⟨ r 2 ⟩ {\displaystyle \scriptstyle \left\langle \rho ^{2}\right\rangle \;=\;\left\langle x^{2}\right\rangle \;+\;\left\langle y^{2}\right\rangle \;=\;{\frac {2}{3}}\left\langle r^{2}\right\rangle } . If n {\displaystyle n} is the number of atoms per unit volume, the volume diamagnetic susceptibility in SI units is
In atoms, Langevin susceptibility is of the same order of magnitude as Van Vleck paramagnetic susceptibility.
The Langevin theory is not the full picture for metals because there are also non-localized electrons. The theory that describes diamagnetism in a free electron gas is called Landau diamagnetism, named after Lev Landau, and instead considers the weak counteracting field that forms when the electrons' trajectories are curved due to the Lorentz force. Landau diamagnetism, however, should be contrasted with Pauli paramagnetism, an effect associated with the polarization of delocalized electrons' spins. For the bulk case of a 3D system and low magnetic fields, the (volume) diamagnetic susceptibility can be calculated using Landau quantization, which in SI units is
where E F {\displaystyle E_{\rm {F}}} is the Fermi energy. This is equivalent to − μ 0 μ B 2 g ( E F ) / 3 {\displaystyle -\mu _{0}\mu _{\rm {B}}^{2}g(E_{\rm {F}})/3} , exactly − 1 / 3 {\textstyle -1/3} times Pauli paramagnetic susceptibility, where μ B = e ℏ / 2 m {\displaystyle \mu _{\rm {B}}=e\hbar /2m} is the Bohr magneton and g ( E ) {\displaystyle g(E)} is the density of states (number of states per energy per volume). This formula takes into account the spin degeneracy of the carriers (spin ½ electrons).
In doped semiconductors the ratio between Landau and Pauli susceptibilities may change due to the effective mass of the charge carriers differing from the electron mass in vacuum, increasing the diamagnetic contribution. The formula presented here only applies for the bulk; in confined systems like quantum dots, the description is altered due to quantum confinement. Additionally, for strong magnetic fields, the susceptibility of delocalized electrons oscillates as a function of the field strength, a phenomenon known as the De Haas–Van Alphen effect, also first described theoretically by Landau. | [
{
"paragraph_id": 0,
"text": "Diamagnetism is the property of materials that are repelled by a magnetic field; an applied magnetic field creates an induced magnetic field in them in the opposite direction, causing a repulsive force. In contrast, paramagnetic and ferromagnetic materials are attracted by a magnetic field. Diamagnetism is a quantum mechanical effect that occurs in all materials; when it is the only contribution to the magnetism, the material is called diamagnetic. In paramagnetic and ferromagnetic substances, the weak diamagnetic force is overcome by the attractive force of magnetic dipoles in the material. The magnetic permeability of diamagnetic materials is less than the permeability of vacuum, μ0. In most materials, diamagnetism is a weak effect which can be detected only by sensitive laboratory instruments, but a superconductor acts as a strong diamagnet because it entirely expels any magnetic field from its interior (the Meissner effect).",
"title": ""
},
{
"paragraph_id": 1,
"text": "Diamagnetism was first discovered when Anton Brugmans observed in 1778 that bismuth was repelled by magnetic fields. In 1845, Michael Faraday demonstrated that it was a property of matter and concluded that every material responded (in either a diamagnetic or paramagnetic way) to an applied magnetic field. On a suggestion by William Whewell, Faraday first referred to the phenomenon as diamagnetic (the prefix dia- meaning through or across), then later changed it to diamagnetism.",
"title": ""
},
{
"paragraph_id": 2,
"text": "A simple rule of thumb is used in chemistry to determine whether a particle (atom, ion, or molecule) is paramagnetic or diamagnetic: If all electrons in the particle are paired, then the substance made of this particle is diamagnetic; If it has unpaired electrons, then the substance is paramagnetic.",
"title": ""
},
{
"paragraph_id": 3,
"text": "Diamagnetism is a property of all materials, and always makes a weak contribution to the material's response to a magnetic field. However, other forms of magnetism (such as ferromagnetism or paramagnetism) are so much stronger such that, when different forms of magnetism are present in a material, the diamagnetic contribution is usually negligible. Substances where the diamagnetic behaviour is the strongest effect are termed diamagnetic materials, or diamagnets. Diamagnetic materials are those that some people generally think of as non-magnetic, and include water, wood, most organic compounds such as petroleum and some plastics, and many metals including copper, particularly the heavy ones with many core electrons, such as mercury, gold and bismuth. The magnetic susceptibility values of various molecular fragments are called Pascal's constants (named after Paul Pascal [fr]).",
"title": "Materials"
},
{
"paragraph_id": 4,
"text": "Diamagnetic materials, like water, or water-based materials, have a relative magnetic permeability that is less than or equal to 1, and therefore a magnetic susceptibility less than or equal to 0, since susceptibility is defined as χv = μv − 1. This means that diamagnetic materials are repelled by magnetic fields. However, since diamagnetism is such a weak property, its effects are not observable in everyday life. For example, the magnetic susceptibility of diamagnets such as water is χv = −9.05×10. The most strongly diamagnetic material is bismuth, χv = −1.66×10, although pyrolytic carbon may have a susceptibility of χv = −4.00×10 in one plane. Nevertheless, these values are orders of magnitude smaller than the magnetism exhibited by paramagnets and ferromagnets. Because χv is derived from the ratio of the internal magnetic field to the applied field, it is a dimensionless value.",
"title": "Materials"
},
{
"paragraph_id": 5,
"text": "In rare cases, the diamagnetic contribution can be stronger than paramagnetic contribution. This is the case for gold, which has a magnetic susceptibility less than 0 (and is thus by definition a diamagnetic material), but when measured carefully with X-ray magnetic circular dichroism, has an extremely weak paramagnetic contribution that is overcome by a stronger diamagnetic contribution.",
"title": "Materials"
},
{
"paragraph_id": 6,
"text": "",
"title": "Materials"
},
{
"paragraph_id": 7,
"text": "Superconductors may be considered perfect diamagnets (χv = −1), because they expel all magnetic fields (except in a thin surface layer) due to the Meissner effect.",
"title": "Materials"
},
{
"paragraph_id": 8,
"text": "If a powerful magnet (such as a supermagnet) is covered with a layer of water (that is thin compared to the diameter of the magnet) then the field of the magnet significantly repels the water. This causes a slight dimple in the water's surface that may be seen by a reflection in its surface.",
"title": "Demonstrations"
},
{
"paragraph_id": 9,
"text": "Diamagnets may be levitated in stable equilibrium in a magnetic field, with no power consumption. Earnshaw's theorem seems to preclude the possibility of static magnetic levitation. However, Earnshaw's theorem applies only to objects with positive susceptibilities, such as ferromagnets (which have a permanent positive moment) and paramagnets (which induce a positive moment). These are attracted to field maxima, which do not exist in free space. Diamagnets (which induce a negative moment) are attracted to field minima, and there can be a field minimum in free space.",
"title": "Demonstrations"
},
{
"paragraph_id": 10,
"text": "A thin slice of pyrolytic graphite, which is an unusually strongly diamagnetic material, can be stably floated in a magnetic field, such as that from rare earth permanent magnets. This can be done with all components at room temperature, making a visually effective and relatively convenient demonstration of diamagnetism.",
"title": "Demonstrations"
},
{
"paragraph_id": 11,
"text": "The Radboud University Nijmegen, the Netherlands, has conducted experiments where water and other substances were successfully levitated. Most spectacularly, a live frog (see figure) was levitated.",
"title": "Demonstrations"
},
{
"paragraph_id": 12,
"text": "In September 2009, NASA's Jet Propulsion Laboratory (JPL) in Pasadena, California announced it had successfully levitated mice using a superconducting magnet, an important step forward since mice are closer biologically to humans than frogs. JPL said it hopes to perform experiments regarding the effects of microgravity on bone and muscle mass.",
"title": "Demonstrations"
},
{
"paragraph_id": 13,
"text": "Recent experiments studying the growth of protein crystals have led to a technique using powerful magnets to allow growth in ways that counteract Earth's gravity.",
"title": "Demonstrations"
},
{
"paragraph_id": 14,
"text": "A simple homemade device for demonstration can be constructed out of bismuth plates and a few permanent magnets that levitate a permanent magnet.",
"title": "Demonstrations"
},
{
"paragraph_id": 15,
"text": "The electrons in a material generally settle in orbitals, with effectively zero resistance and act like current loops. Thus it might be imagined that diamagnetism effects in general would be common, since any applied magnetic field would generate currents in these loops that would oppose the change, in a similar way to superconductors, which are essentially perfect diamagnets. However, since the electrons are rigidly held in orbitals by the charge of the protons and are further constrained by the Pauli exclusion principle, many materials exhibit diamagnetism, but typically respond very little to the applied field.",
"title": "Theory"
},
{
"paragraph_id": 16,
"text": "The Bohr–Van Leeuwen theorem proves that there cannot be any diamagnetism or paramagnetism in a purely classical system. However, the classical theory of Langevin for diamagnetism gives the same prediction as the quantum theory. The classical theory is given below.",
"title": "Theory"
},
{
"paragraph_id": 17,
"text": "Paul Langevin's theory of diamagnetism (1905) applies to materials containing atoms with closed shells (see dielectrics). A field with intensity B, applied to an electron with charge e and mass m, gives rise to Larmor precession with frequency ω = eB / 2m. The number of revolutions per unit time is ω / 2π, so the current for an atom with Z electrons is (in SI units)",
"title": "Theory"
},
{
"paragraph_id": 18,
"text": "The magnetic moment of a current loop is equal to the current times the area of the loop. Suppose the field is aligned with the z axis. The average loop area can be given as π ⟨ ρ 2 ⟩ {\\displaystyle \\scriptstyle \\pi \\left\\langle \\rho ^{2}\\right\\rangle } , where ⟨ ρ 2 ⟩ {\\displaystyle \\scriptstyle \\left\\langle \\rho ^{2}\\right\\rangle } is the mean square distance of the electrons perpendicular to the z axis. The magnetic moment is therefore",
"title": "Theory"
},
{
"paragraph_id": 19,
"text": "If the distribution of charge is spherically symmetric, we can suppose that the distribution of x,y,z coordinates are independent and identically distributed. Then ⟨ x 2 ⟩ = ⟨ y 2 ⟩ = ⟨ z 2 ⟩ = 1 3 ⟨ r 2 ⟩ {\\displaystyle \\scriptstyle \\left\\langle x^{2}\\right\\rangle \\;=\\;\\left\\langle y^{2}\\right\\rangle \\;=\\;\\left\\langle z^{2}\\right\\rangle \\;=\\;{\\frac {1}{3}}\\left\\langle r^{2}\\right\\rangle } , where ⟨ r 2 ⟩ {\\displaystyle \\scriptstyle \\left\\langle r^{2}\\right\\rangle } is the mean square distance of the electrons from the nucleus. Therefore, ⟨ ρ 2 ⟩ = ⟨ x 2 ⟩ + ⟨ y 2 ⟩ = 2 3 ⟨ r 2 ⟩ {\\displaystyle \\scriptstyle \\left\\langle \\rho ^{2}\\right\\rangle \\;=\\;\\left\\langle x^{2}\\right\\rangle \\;+\\;\\left\\langle y^{2}\\right\\rangle \\;=\\;{\\frac {2}{3}}\\left\\langle r^{2}\\right\\rangle } . If n {\\displaystyle n} is the number of atoms per unit volume, the volume diamagnetic susceptibility in SI units is",
"title": "Theory"
},
{
"paragraph_id": 20,
"text": "In atoms, Langevin susceptibility is of the same order of magnitude as Van Vleck paramagnetic susceptibility.",
"title": "Theory"
},
{
"paragraph_id": 21,
"text": "The Langevin theory is not the full picture for metals because there are also non-localized electrons. The theory that describes diamagnetism in a free electron gas is called Landau diamagnetism, named after Lev Landau, and instead considers the weak counteracting field that forms when the electrons' trajectories are curved due to the Lorentz force. Landau diamagnetism, however, should be contrasted with Pauli paramagnetism, an effect associated with the polarization of delocalized electrons' spins. For the bulk case of a 3D system and low magnetic fields, the (volume) diamagnetic susceptibility can be calculated using Landau quantization, which in SI units is",
"title": "Theory"
},
{
"paragraph_id": 22,
"text": "where E F {\\displaystyle E_{\\rm {F}}} is the Fermi energy. This is equivalent to − μ 0 μ B 2 g ( E F ) / 3 {\\displaystyle -\\mu _{0}\\mu _{\\rm {B}}^{2}g(E_{\\rm {F}})/3} , exactly − 1 / 3 {\\textstyle -1/3} times Pauli paramagnetic susceptibility, where μ B = e ℏ / 2 m {\\displaystyle \\mu _{\\rm {B}}=e\\hbar /2m} is the Bohr magneton and g ( E ) {\\displaystyle g(E)} is the density of states (number of states per energy per volume). This formula takes into account the spin degeneracy of the carriers (spin ½ electrons).",
"title": "Theory"
},
{
"paragraph_id": 23,
"text": "In doped semiconductors the ratio between Landau and Pauli susceptibilities may change due to the effective mass of the charge carriers differing from the electron mass in vacuum, increasing the diamagnetic contribution. The formula presented here only applies for the bulk; in confined systems like quantum dots, the description is altered due to quantum confinement. Additionally, for strong magnetic fields, the susceptibility of delocalized electrons oscillates as a function of the field strength, a phenomenon known as the De Haas–Van Alphen effect, also first described theoretically by Landau.",
"title": "Theory"
},
{
"paragraph_id": 24,
"text": "",
"title": "External links"
}
] | Diamagnetism is the property of materials that are repelled by a magnetic field; an applied magnetic field creates an induced magnetic field in them in the opposite direction, causing a repulsive force. In contrast, paramagnetic and ferromagnetic materials are attracted by a magnetic field. Diamagnetism is a quantum mechanical effect that occurs in all materials; when it is the only contribution to the magnetism, the material is called diamagnetic. In paramagnetic and ferromagnetic substances, the weak diamagnetic force is overcome by the attractive force of magnetic dipoles in the material. The magnetic permeability of diamagnetic materials is less than the permeability of vacuum, μ0. In most materials, diamagnetism is a weak effect which can be detected only by sensitive laboratory instruments, but a superconductor acts as a strong diamagnet because it entirely expels any magnetic field from its interior. Diamagnetism was first discovered when Anton Brugmans observed in 1778 that bismuth was repelled by magnetic fields. In 1845, Michael Faraday demonstrated that it was a property of matter and concluded that every material responded to an applied magnetic field. On a suggestion by William Whewell, Faraday first referred to the phenomenon as diamagnetic, then later changed it to diamagnetism. A simple rule of thumb is used in chemistry to determine whether a particle is paramagnetic or diamagnetic: If all electrons in the particle are paired, then the substance made of this particle is diamagnetic; If it has unpaired electrons, then the substance is paramagnetic. | 2001-08-14T22:33:13Z | 2023-09-26T12:54:29Z | [
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8,317 | Duke of Marlborough (title) | Duke of Marlborough (pronounced /ˈmɔːrlbrə/) is a title in the Peerage of England. It was created by Queen Anne in 1702 for John Churchill, 1st Earl of Marlborough (1650–1722), the noted military leader. In historical texts, unqualified use of the title typically refers to the 1st Duke. The name of the dukedom refers to Marlborough in Wiltshire.
The earldom of Marlborough was held by the family of Ley from its creation in 1626 until its extinction with the death of the 4th earl in 1679. The title was recreated 10 years later for John Churchill (in 1689).
Churchill had been made Lord Churchill of Eyemouth (1682) in the Peerage of Scotland, and Baron Churchill of Sandridge (1685) and Earl of Marlborough (1689) in the Peerage of England. Shortly after her accession to the throne in 1702, Queen Anne made Churchill the first Duke of Marlborough and granted him the subsidiary title Marquess of Blandford.
In 1678, Churchill married Sarah Jennings (1660–1744), a courtier and influential favourite of the queen. They had seven children, of whom four daughters married into some of the most important families in Great Britain; one daughter and one son died in infancy. He was pre-deceased by his son, John Churchill, Marquess of Blandford, in 1703; so, to prevent the extinction of the titles, a special Act of Parliament was passed. When the 1st Duke of Marlborough died in 1722 his title as Lord Churchill of Eyemouth in the Peerage of Scotland became extinct and the Marlborough titles passed, according to the Act, to his eldest daughter Henrietta (1681–1733), the 2nd Duchess of Marlborough. She was married to Francis Godolphin, 2nd Earl of Godolphin and had a son who predeceased her.
When Henrietta died in 1733, the Marlborough titles passed to her nephew Charles Spencer (1706–1758), the third son of her late sister Anne (1683–1716), who had married the 3rd Earl of Sunderland in 1699. After his older brother's death in 1729, Charles Spencer had already inherited the Spencer family estates and the titles of Earl of Sunderland (1643) and Baron Spencer of Wormleighton (1603), all in the Peerage of England. Upon his maternal aunt Henrietta's death in 1733, Charles Spencer succeeded to the Marlborough family estates and titles and became the 3rd Duke. When he died in 1758, his titles passed to his eldest son George (1739–1817), who was succeeded by his eldest son George, the 5th Duke (1766–1840). In 1815, Francis Spencer (the younger son of the 4th Duke) was created Baron Churchill in the Peerage of the United Kingdom. In 1902, his grandson, the 3rd Baron Churchill, was created Viscount Churchill.
In 1817, the 5th Duke obtained permission to assume and bear the surname of Churchill in addition to his surname of Spencer, to perpetuate the name of his illustrious great-great-grandfather. At the same time he received Royal Licence to quarter the coat of arms of Churchill with his paternal arms of Spencer. The modern Dukes thus originally bore the surname "Spencer": the double-barrelled surname of "Spencer-Churchill" as used since 1817 remains in the family, although many members have preferred to style themselves simply as "Churchill".
The 7th Duke was the paternal grandfather of the British Prime Minister Sir Winston Churchill, born at Blenheim Palace on 30 November 1874.
The 11th Duke, John Spencer-Churchill died in 2014, having assumed the title in 1972. The 12th and present Duke is Charles James Spencer-Churchill.
The family seat is Blenheim Palace in Woodstock, Oxfordshire.
After his leadership in the victory against the French in the Battle of Blenheim on 13 August 1704, the 1st Duke was honoured by Queen Anne granting him the royal manor of Woodstock, and building him a house at her expense to be called Blenheim. Construction started in 1705 and the house was completed in 1722, the year of the 1st Duke's death. Blenheim Palace has since remained in the Churchill and Spencer-Churchill family.
With the exception of the 10th Duke and his first wife, the dukes and duchesses of Marlborough are buried in Blenheim Palace's chapel. Most other members of the Spencer-Churchill family are interred in St. Martin's parish churchyard at Bladon, a short distance from the palace.
The dukedom can theoretically pass through a female line. However, unlike the remainder to heirs general found in most other peerages that allow male-preference primogeniture, the grant does not allow for abeyance and follows a more restrictive Semi-Salic formula designed to keep succession wherever possible in the male line.
Succession to the title under the first and second contingencies has lapsed; holders of the title from the 3rd Duke trace their status from the third contingency.
It is now very unlikely that the dukedom will be passed to a woman or through a woman, since all the male-line descendants of the 1st Duke's second daughter Anne Spencer, Countess of Sunderland—including the lines of the Viscounts Churchill and Barons Churchill of Wychwood and of the Earl Spencer and of the entire Spencer-Churchill and Spencer family—would have to become extinct.
If that were to happen, the Churchill titles would pass to the Earl of Jersey, the heir-male of the 1st Duke's granddaughter Anne Villiers (born Egerton), Countess of Jersey, daughter of Elizabeth Egerton, Duchess of Bridgewater, the third daughter of the first Duke.
The Duke holds subsidiary titles: Marquess of Blandford (created in 1702 for John Churchill), Earl of Sunderland (created in 1643 for the Spencer family), Earl of Marlborough (created in 1689 for John Churchill), Baron Spencer of Wormleighton (created in 1603 for the Spencer family), and Baron Churchill of Sandridge (created in 1685 for John Churchill), all in the Peerage of England.
The title Marquess of Blandford is used as the courtesy title for the Duke's eldest son and heir. The Duke's eldest son's eldest son can use the courtesy title Earl of Sunderland, and the duke's eldest son's eldest son's eldest son (not necessarily the eldest great-grandson) the title Lord Spencer of Wormleighton (not to be confused with Earl Spencer).
The title of Earl of Marlborough, created for John Churchill in 1689, had previously been created for James Ley, in 1626, becoming extinct in 1679.
The 1st Duke was honoured with land and titles in the Holy Roman Empire: Emperor Leopold I created him a Prince in 1704, and in 1705, his successor Emperor Joseph I gave him the principality of Mindelheim (once the lordship of the noted soldier Georg von Frundsberg). He was obliged to surrender Mindelheim in 1714 by the Treaty of Utrecht, which returned it to Bavaria. He tried to obtain Nellenburg in Austria in exchange, which at that time was only a county ('Landgrafschaft'), but this failed, partially because Austrian law did not allow for Nellenburg to be converted into a sovereign principality. The 1st Duke's princely title of Mindelheim became extinct either on the return of the land to Bavaria or on his death, as the Empire operated Salic Law, which prevented female succession.
The original arms of Sir Winston Churchill (1620–1688), father of the 1st Duke of Marlborough, were simple and in use by his own father in 1619. The shield was Sable a lion rampant Argent, debruised by a bendlet Gules. The addition of a canton of Saint George (see below) rendered the distinguishing mark of the bendlet unnecessary.
The Churchill crest is blazoned as a lion couchant guardant Argent, supporting with its dexter forepaw a banner Gules, charged with a dexter hand appaumée of the first, staff Or.
In recognition of Sir Winston's services to King Charles I as Captain of the Horse, and his loyalty to King Charles II as a Member of Parliament, he was awarded an augmentation of honour to his arms around 1662. This rare mark of royal favour took the form of a canton of Saint George. At the same time, he was authorised to omit the bendlet, which had served the purpose of distinguishing this branch of the Churchill family from others which bore an undifferenced lion.
Sir Winston's shield and crest were inherited by his son John Churchill, 1st Duke of Marlborough. Minor modifications reflected the bearer's social rise: the helm was now shown in profile and had a closed grille to signify the bearer's rank as a peer, and there were now supporters placed on either side of the shield. They were the mythical Griffin (part lion, part eagle) and Wyvern (a dragon without hind legs). The supporters were derived from the arms of the family of the 1st Duke's mother, Drake of Ash (Argent, a wyvern gules; these arms can be seen on the monument in Musbury Church to Sir Bernard Drake, d.1586).
The motto was Fiel pero desdichado (Spanish for "Faithful but unfortunate"). The 1st Duke was also entitled to a coronet indicating his rank.
When the 1st Duke was made a Prince of the Holy Roman Empire in 1705, two unusual features were added: the Imperial Eagle and a Princely Coronet. His estates in Germany, such as Mindelheim, were represented in his arms by additional quarterings.
In 1817, the 5th Duke received Royal Licence to place the quarter of Churchill ahead of his paternal arms of Spencer. The shield of the Spencer family arms is: quarterly Argent and Gules, in the second and third quarters a fret Or, over all on a bend Sable three escallops of the first. The Spencer crest is: out of a ducal coronet Or, a griffin's head between two wings expanded Argent, gorged with a collar gemel and armed Gules. Paul Courtenay observes that "It would be normal in these circumstances for the paternal arms (Spencer) to take precedence over the maternal (Churchill), but because the Marlborough dukedom was senior to the Sunderland earldom, the procedure was reversed in this case."
Also in 1817, a further augmentation of honour was added to his armorial achievement. This incorporated the bearings from the standard of the Manor of Woodstock and was borne on an escutcheon, displayed over all in the centre chief point, as follows: Argent a cross of Saint George surmounted by an inescutcheon Azure, charged with three fleurs-de-lys Or, two over one. This inescutcheon represents the royal arms of France.
These quartered arms, incorporating the two augmentations of honour, have been the arms of all subsequent Dukes of Marlborough.
The motto Fiel pero desdichado is Spanish for 'Faithful but unfortunate'. Desdichado means without happiness or without joy, alluding to the first Duke's father, Winston, who was a royalist and faithful supporter of the king during the English Civil War but was not compensated for his losses after the restoration. Charles II knighted Winston Churchill and other Civil War royalists but did not compensate them for their wartime losses, thereby inducing Winston to adopt the motto. It is unusual for the motto of an Englishman of the era to be in Spanish rather than Latin, and it is not known why this is the case.
The earldom of Marlborough was held by the family of Ley from 1626 to 1679. James Ley, the 1st Earl (c. 1550 – 1629), was lord chief justice of the King’s Bench in Ireland and then in England; he was an English member of parliament and was lord high treasurer from 1624 to 1628. In 1624 he was created Baron Ley and in 1626 Earl of Marlborough. The 3rd earl was his grandson James (1618–1665), a naval officer who was killed in action with the Dutch. James was succeeded by his uncle William, a younger son of the 1st earl, on whose death in 1679 the earldom became extinct.
The heir apparent to the dukedom is George John Godolphin Spencer-Churchill, Marquess of Blandford (b. 1992), eldest son of the 12th Duke. | [
{
"paragraph_id": 0,
"text": "Duke of Marlborough (pronounced /ˈmɔːrlbrə/) is a title in the Peerage of England. It was created by Queen Anne in 1702 for John Churchill, 1st Earl of Marlborough (1650–1722), the noted military leader. In historical texts, unqualified use of the title typically refers to the 1st Duke. The name of the dukedom refers to Marlborough in Wiltshire.",
"title": ""
},
{
"paragraph_id": 1,
"text": "The earldom of Marlborough was held by the family of Ley from its creation in 1626 until its extinction with the death of the 4th earl in 1679. The title was recreated 10 years later for John Churchill (in 1689).",
"title": ""
},
{
"paragraph_id": 2,
"text": "Churchill had been made Lord Churchill of Eyemouth (1682) in the Peerage of Scotland, and Baron Churchill of Sandridge (1685) and Earl of Marlborough (1689) in the Peerage of England. Shortly after her accession to the throne in 1702, Queen Anne made Churchill the first Duke of Marlborough and granted him the subsidiary title Marquess of Blandford.",
"title": "History of the dukedom"
},
{
"paragraph_id": 3,
"text": "In 1678, Churchill married Sarah Jennings (1660–1744), a courtier and influential favourite of the queen. They had seven children, of whom four daughters married into some of the most important families in Great Britain; one daughter and one son died in infancy. He was pre-deceased by his son, John Churchill, Marquess of Blandford, in 1703; so, to prevent the extinction of the titles, a special Act of Parliament was passed. When the 1st Duke of Marlborough died in 1722 his title as Lord Churchill of Eyemouth in the Peerage of Scotland became extinct and the Marlborough titles passed, according to the Act, to his eldest daughter Henrietta (1681–1733), the 2nd Duchess of Marlborough. She was married to Francis Godolphin, 2nd Earl of Godolphin and had a son who predeceased her.",
"title": "History of the dukedom"
},
{
"paragraph_id": 4,
"text": "When Henrietta died in 1733, the Marlborough titles passed to her nephew Charles Spencer (1706–1758), the third son of her late sister Anne (1683–1716), who had married the 3rd Earl of Sunderland in 1699. After his older brother's death in 1729, Charles Spencer had already inherited the Spencer family estates and the titles of Earl of Sunderland (1643) and Baron Spencer of Wormleighton (1603), all in the Peerage of England. Upon his maternal aunt Henrietta's death in 1733, Charles Spencer succeeded to the Marlborough family estates and titles and became the 3rd Duke. When he died in 1758, his titles passed to his eldest son George (1739–1817), who was succeeded by his eldest son George, the 5th Duke (1766–1840). In 1815, Francis Spencer (the younger son of the 4th Duke) was created Baron Churchill in the Peerage of the United Kingdom. In 1902, his grandson, the 3rd Baron Churchill, was created Viscount Churchill.",
"title": "History of the dukedom"
},
{
"paragraph_id": 5,
"text": "In 1817, the 5th Duke obtained permission to assume and bear the surname of Churchill in addition to his surname of Spencer, to perpetuate the name of his illustrious great-great-grandfather. At the same time he received Royal Licence to quarter the coat of arms of Churchill with his paternal arms of Spencer. The modern Dukes thus originally bore the surname \"Spencer\": the double-barrelled surname of \"Spencer-Churchill\" as used since 1817 remains in the family, although many members have preferred to style themselves simply as \"Churchill\".",
"title": "History of the dukedom"
},
{
"paragraph_id": 6,
"text": "The 7th Duke was the paternal grandfather of the British Prime Minister Sir Winston Churchill, born at Blenheim Palace on 30 November 1874.",
"title": "History of the dukedom"
},
{
"paragraph_id": 7,
"text": "The 11th Duke, John Spencer-Churchill died in 2014, having assumed the title in 1972. The 12th and present Duke is Charles James Spencer-Churchill.",
"title": "History of the dukedom"
},
{
"paragraph_id": 8,
"text": "The family seat is Blenheim Palace in Woodstock, Oxfordshire.",
"title": "Family seat"
},
{
"paragraph_id": 9,
"text": "After his leadership in the victory against the French in the Battle of Blenheim on 13 August 1704, the 1st Duke was honoured by Queen Anne granting him the royal manor of Woodstock, and building him a house at her expense to be called Blenheim. Construction started in 1705 and the house was completed in 1722, the year of the 1st Duke's death. Blenheim Palace has since remained in the Churchill and Spencer-Churchill family.",
"title": "Family seat"
},
{
"paragraph_id": 10,
"text": "With the exception of the 10th Duke and his first wife, the dukes and duchesses of Marlborough are buried in Blenheim Palace's chapel. Most other members of the Spencer-Churchill family are interred in St. Martin's parish churchyard at Bladon, a short distance from the palace.",
"title": "Family seat"
},
{
"paragraph_id": 11,
"text": "The dukedom can theoretically pass through a female line. However, unlike the remainder to heirs general found in most other peerages that allow male-preference primogeniture, the grant does not allow for abeyance and follows a more restrictive Semi-Salic formula designed to keep succession wherever possible in the male line.",
"title": "Succession to the title"
},
{
"paragraph_id": 12,
"text": "Succession to the title under the first and second contingencies has lapsed; holders of the title from the 3rd Duke trace their status from the third contingency.",
"title": "Succession to the title"
},
{
"paragraph_id": 13,
"text": "It is now very unlikely that the dukedom will be passed to a woman or through a woman, since all the male-line descendants of the 1st Duke's second daughter Anne Spencer, Countess of Sunderland—including the lines of the Viscounts Churchill and Barons Churchill of Wychwood and of the Earl Spencer and of the entire Spencer-Churchill and Spencer family—would have to become extinct.",
"title": "Succession to the title"
},
{
"paragraph_id": 14,
"text": "If that were to happen, the Churchill titles would pass to the Earl of Jersey, the heir-male of the 1st Duke's granddaughter Anne Villiers (born Egerton), Countess of Jersey, daughter of Elizabeth Egerton, Duchess of Bridgewater, the third daughter of the first Duke.",
"title": "Succession to the title"
},
{
"paragraph_id": 15,
"text": "The Duke holds subsidiary titles: Marquess of Blandford (created in 1702 for John Churchill), Earl of Sunderland (created in 1643 for the Spencer family), Earl of Marlborough (created in 1689 for John Churchill), Baron Spencer of Wormleighton (created in 1603 for the Spencer family), and Baron Churchill of Sandridge (created in 1685 for John Churchill), all in the Peerage of England.",
"title": "Other titles of the Dukes"
},
{
"paragraph_id": 16,
"text": "The title Marquess of Blandford is used as the courtesy title for the Duke's eldest son and heir. The Duke's eldest son's eldest son can use the courtesy title Earl of Sunderland, and the duke's eldest son's eldest son's eldest son (not necessarily the eldest great-grandson) the title Lord Spencer of Wormleighton (not to be confused with Earl Spencer).",
"title": "Other titles of the Dukes"
},
{
"paragraph_id": 17,
"text": "The title of Earl of Marlborough, created for John Churchill in 1689, had previously been created for James Ley, in 1626, becoming extinct in 1679.",
"title": "Other titles of the Dukes"
},
{
"paragraph_id": 18,
"text": "The 1st Duke was honoured with land and titles in the Holy Roman Empire: Emperor Leopold I created him a Prince in 1704, and in 1705, his successor Emperor Joseph I gave him the principality of Mindelheim (once the lordship of the noted soldier Georg von Frundsberg). He was obliged to surrender Mindelheim in 1714 by the Treaty of Utrecht, which returned it to Bavaria. He tried to obtain Nellenburg in Austria in exchange, which at that time was only a county ('Landgrafschaft'), but this failed, partially because Austrian law did not allow for Nellenburg to be converted into a sovereign principality. The 1st Duke's princely title of Mindelheim became extinct either on the return of the land to Bavaria or on his death, as the Empire operated Salic Law, which prevented female succession.",
"title": "Other titles of the Dukes"
},
{
"paragraph_id": 19,
"text": "The original arms of Sir Winston Churchill (1620–1688), father of the 1st Duke of Marlborough, were simple and in use by his own father in 1619. The shield was Sable a lion rampant Argent, debruised by a bendlet Gules. The addition of a canton of Saint George (see below) rendered the distinguishing mark of the bendlet unnecessary.",
"title": "Coats of arms"
},
{
"paragraph_id": 20,
"text": "The Churchill crest is blazoned as a lion couchant guardant Argent, supporting with its dexter forepaw a banner Gules, charged with a dexter hand appaumée of the first, staff Or.",
"title": "Coats of arms"
},
{
"paragraph_id": 21,
"text": "In recognition of Sir Winston's services to King Charles I as Captain of the Horse, and his loyalty to King Charles II as a Member of Parliament, he was awarded an augmentation of honour to his arms around 1662. This rare mark of royal favour took the form of a canton of Saint George. At the same time, he was authorised to omit the bendlet, which had served the purpose of distinguishing this branch of the Churchill family from others which bore an undifferenced lion.",
"title": "Coats of arms"
},
{
"paragraph_id": 22,
"text": "Sir Winston's shield and crest were inherited by his son John Churchill, 1st Duke of Marlborough. Minor modifications reflected the bearer's social rise: the helm was now shown in profile and had a closed grille to signify the bearer's rank as a peer, and there were now supporters placed on either side of the shield. They were the mythical Griffin (part lion, part eagle) and Wyvern (a dragon without hind legs). The supporters were derived from the arms of the family of the 1st Duke's mother, Drake of Ash (Argent, a wyvern gules; these arms can be seen on the monument in Musbury Church to Sir Bernard Drake, d.1586).",
"title": "Coats of arms"
},
{
"paragraph_id": 23,
"text": "The motto was Fiel pero desdichado (Spanish for \"Faithful but unfortunate\"). The 1st Duke was also entitled to a coronet indicating his rank.",
"title": "Coats of arms"
},
{
"paragraph_id": 24,
"text": "When the 1st Duke was made a Prince of the Holy Roman Empire in 1705, two unusual features were added: the Imperial Eagle and a Princely Coronet. His estates in Germany, such as Mindelheim, were represented in his arms by additional quarterings.",
"title": "Coats of arms"
},
{
"paragraph_id": 25,
"text": "In 1817, the 5th Duke received Royal Licence to place the quarter of Churchill ahead of his paternal arms of Spencer. The shield of the Spencer family arms is: quarterly Argent and Gules, in the second and third quarters a fret Or, over all on a bend Sable three escallops of the first. The Spencer crest is: out of a ducal coronet Or, a griffin's head between two wings expanded Argent, gorged with a collar gemel and armed Gules. Paul Courtenay observes that \"It would be normal in these circumstances for the paternal arms (Spencer) to take precedence over the maternal (Churchill), but because the Marlborough dukedom was senior to the Sunderland earldom, the procedure was reversed in this case.\"",
"title": "Coats of arms"
},
{
"paragraph_id": 26,
"text": "Also in 1817, a further augmentation of honour was added to his armorial achievement. This incorporated the bearings from the standard of the Manor of Woodstock and was borne on an escutcheon, displayed over all in the centre chief point, as follows: Argent a cross of Saint George surmounted by an inescutcheon Azure, charged with three fleurs-de-lys Or, two over one. This inescutcheon represents the royal arms of France.",
"title": "Coats of arms"
},
{
"paragraph_id": 27,
"text": "These quartered arms, incorporating the two augmentations of honour, have been the arms of all subsequent Dukes of Marlborough.",
"title": "Coats of arms"
},
{
"paragraph_id": 28,
"text": "The motto Fiel pero desdichado is Spanish for 'Faithful but unfortunate'. Desdichado means without happiness or without joy, alluding to the first Duke's father, Winston, who was a royalist and faithful supporter of the king during the English Civil War but was not compensated for his losses after the restoration. Charles II knighted Winston Churchill and other Civil War royalists but did not compensate them for their wartime losses, thereby inducing Winston to adopt the motto. It is unusual for the motto of an Englishman of the era to be in Spanish rather than Latin, and it is not known why this is the case.",
"title": "Coats of arms"
},
{
"paragraph_id": 29,
"text": "The earldom of Marlborough was held by the family of Ley from 1626 to 1679. James Ley, the 1st Earl (c. 1550 – 1629), was lord chief justice of the King’s Bench in Ireland and then in England; he was an English member of parliament and was lord high treasurer from 1624 to 1628. In 1624 he was created Baron Ley and in 1626 Earl of Marlborough. The 3rd earl was his grandson James (1618–1665), a naval officer who was killed in action with the Dutch. James was succeeded by his uncle William, a younger son of the 1st earl, on whose death in 1679 the earldom became extinct.",
"title": "List of title holders"
},
{
"paragraph_id": 30,
"text": "The heir apparent to the dukedom is George John Godolphin Spencer-Churchill, Marquess of Blandford (b. 1992), eldest son of the 12th Duke.",
"title": "List of title holders"
},
{
"paragraph_id": 31,
"text": "",
"title": "Family tree"
},
{
"paragraph_id": 32,
"text": "",
"title": "Family tree"
}
] | Duke of Marlborough is a title in the Peerage of England. It was created by Queen Anne in 1702 for John Churchill, 1st Earl of Marlborough (1650–1722), the noted military leader. In historical texts, unqualified use of the title typically refers to the 1st Duke. The name of the dukedom refers to Marlborough in Wiltshire. The earldom of Marlborough was held by the family of Ley from its creation in 1626 until its extinction with the death of the 4th earl in 1679. The title was recreated 10 years later for John Churchill. | 2001-08-15T18:49:37Z | 2023-09-17T20:27:00Z | [
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8,322 | December 17 | December 17 is the 351st day of the year (352nd in leap years) in the Gregorian calendar; 14 days remain until the end of the year. | [
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"text": "December 17 is the 351st day of the year (352nd in leap years) in the Gregorian calendar; 14 days remain until the end of the year.",
"title": ""
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] | December 17 is the 351st day of the year in the Gregorian calendar; 14 days remain until the end of the year. | 2001-10-15T15:13:57Z | 2023-12-24T17:11:13Z | [
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8,324 | Difference engine | A difference engine is an automatic mechanical calculator designed to tabulate polynomial functions. It was designed in the 1820s, and was first created by Charles Babbage. The name difference engine is derived from the method of divided differences, a way to interpolate or tabulate functions by using a small set of polynomial co-efficients. Some of the most common mathematical functions used in engineering, science and navigation, are built from logarithmic and trigonometric functions, which can be approximated by polynomials, so a difference engine can compute many useful tables.
The notion of a mechanical calculator for mathematical functions can be traced back to the Antikythera mechanism of the 2nd century BC, while early modern examples are attributed to Pascal and Leibniz in the 17th century.
In 1784 J. H. Müller, an engineer in the Hessian army, devised and built an adding machine and described the basic principles of a difference machine in a book published in 1786 (the first written reference to a difference machine is dated to 1784), but he was unable to obtain funding to progress with the idea.
Charles Babbage began to construct a small difference engine in c. 1819 and had completed it by 1822 (Difference Engine 0). He announced his invention on 14 June 1822, in a paper to the Royal Astronomical Society, entitled "Note on the application of machinery to the computation of astronomical and mathematical tables". This machine used the decimal number system and was powered by cranking a handle. The British government was interested, since producing tables was time-consuming and expensive and they hoped the difference engine would make the task more economical.
In 1823, the British government gave Babbage £1700 to start work on the project. Although Babbage's design was feasible, the metalworking techniques of the era could not economically make parts in the precision and quantity required. Thus the implementation proved to be much more expensive and doubtful of success than the government's initial estimate. According to the 1830 design for Difference Engine No. 1, it would have about 25,000 parts, weigh 4 tons, and operate on 20-digit numbers by sixth-order differences. In 1832, Babbage and Joseph Clement produced a small working model (one-seventh of the plan), which operated on 6-digit numbers by second-order differences. Lady Byron described seeing the working prototype in 1833: "We both went to see the thinking machine (or so it seems) last Monday. It raised several Nos. to the 2nd and 3rd powers, and extracted the root of a Quadratic equation." Work on the larger engine was suspended in 1833.
By the time the government abandoned the project in 1842, Babbage had received and spent over £17,000 on development, which still fell short of achieving a working engine. The government valued only the machine's output (economically produced tables), not the development (at unpredictable cost) of the machine itself. Babbage refused to recognize that predicament. Meanwhile, Babbage's attention had moved on to developing an analytical engine, further undermining the government's confidence in the eventual success of the difference engine. By improving the concept as an analytical engine, Babbage had made the difference engine concept obsolete, and the project to implement it an utter failure in the view of the government.
The incomplete Difference Engine No. 1 was put on display to the public at the 1862 International Exhibition in South Kensington, London.
Babbage went on to design his much more general analytical engine, but later produced an improved "Difference Engine No. 2" design (31-digit numbers and seventh-order differences), between 1846 and 1849. Babbage was able to take advantage of ideas developed for the analytical engine to make the new difference engine calculate more quickly while using fewer parts.
Inspired by Babbage's difference engine in 1834, Per Georg Scheutz built several experimental models. In 1837 his son Edward proposed to construct a working model in metal, and in 1840 finished the calculating part, capable of calculating series with 5-digit numbers and first-order differences, which was later extended to third-order (1842). In 1843, after adding the printing part, the model was completed.
In 1851, funded by the government, construction of the larger and improved (15-digit numbers and fourth-order differences) machine began, and finished in 1853. The machine was demonstrated at the World's Fair in Paris, 1855 and then sold in 1856 to the Dudley Observatory in Albany, New York. Delivered in 1857, it was the first printing calculator sold. In 1857 the British government ordered the next Scheutz's difference machine, which was built in 1859. It had the same basic construction as the previous one, weighing about 10 cwt (1,100 lb; 510 kg).
Martin Wiberg improved Scheutz's construction (c. 1859, his machine has the same capacity as Scheutz's: 15-digit and fourth-order) but used his device only for producing and publishing printed tables (interest tables in 1860, and logarithmic tables in 1875).
Alfred Deacon of London in c. 1862 produced a small difference engine (20-digit numbers and third-order differences).
American George B. Grant started working on his calculating machine in 1869, unaware of the works of Babbage and Scheutz (Schentz). One year later (1870) he learned about difference engines and proceeded to design one himself, describing his construction in 1871. In 1874 the Boston Thursday Club raised a subscription for the construction of a large-scale model, which was built in 1876. It could be expanded to enhance precision and weighed about 2,000 pounds (910 kg).
Christel Hamann built one machine (16-digit numbers and second-order differences) in 1909 for the "Tables of Bauschinger and Peters" ("Logarithmic-Trigonometrical Tables with eight decimal places"), which was first published in Leipzig in 1910. It weighed about 40 kilograms (88 lb).
Burroughs Corporation in about 1912 built a machine for the Nautical Almanac Office which was used as a difference engine of second-order. It was later replaced in 1929 by a Burroughs Class 11 (13-digit numbers and second-order differences, or 11-digit numbers and [at least up to] fifth-order differences).
Alexander John Thompson about 1927 built integrating and differencing machine (13-digit numbers and fifth-order differences) for his table of logarithms "Logarithmetica britannica". This machine was composed of four modified Triumphator calculators.
Leslie Comrie in 1928 described how to use the Brunsviga-Dupla calculating machine as a difference engine of second-order (15-digit numbers). He also noted in 1931 that National Accounting Machine Class 3000 could be used as a difference engine of sixth-order.
During the 1980s, Allan G. Bromley, an associate professor at the University of Sydney, Australia, studied Babbage's original drawings for the Difference and Analytical Engines at the Science Museum library in London. This work led the Science Museum to construct a working calculating section of difference engine No. 2 from 1985 to 1991, under Doron Swade, the then Curator of Computing. This was to celebrate the 200th anniversary of Babbage's birth in 1991. In 2002, the printer which Babbage originally designed for the difference engine was also completed. The conversion of the original design drawings into drawings suitable for engineering manufacturers' use revealed some minor errors in Babbage's design (possibly introduced as a protection in case the plans were stolen), which had to be corrected. The difference engine and printer were constructed to tolerances achievable with 19th-century technology, resolving a long-standing debate as to whether Babbage's design could have worked using Georgian-era engineering methods. The machine contains 8,000 parts and weighs about 5 tons.
The printer's primary purpose is to produce stereotype plates for use in printing presses, which it does by pressing type into soft plaster to create a flong. Babbage intended that the Engine's results be conveyed directly to mass printing, having recognized that many errors in previous tables were not the result of human calculating mistakes but from slips in the manual typesetting process. The printer's paper output is mainly a means of checking the engine's performance.
In addition to funding the construction of the output mechanism for the Science Museum's difference engine, Nathan Myhrvold commissioned the construction of a second complete Difference Engine No. 2, which was on exhibit at the Computer History Museum in Mountain View, California from May 2008 to January 2016. It has since been transferred to Intellectual Ventures in Seattle where it is on display just outside the main lobby.
The difference engine consists of a number of columns, numbered from 1 to N. The machine is able to store one decimal number in each column. The machine can only add the value of a column n + 1 to column n to produce the new value of n. Column N can only store a constant, column 1 displays (and possibly prints) the value of the calculation on the current iteration.
The engine is programmed by setting initial values to the columns. Column 1 is set to the value of the polynomial at the start of computation. Column 2 is set to a value derived from the first and higher derivatives of the polynomial at the same value of X. Each of the columns from 3 to N is set to a value derived from the ( n − 1 ) {\displaystyle (n-1)} first and higher derivatives of the polynomial.
In the Babbage design, one iteration (i.e. one full set of addition and carry operations) happens for each rotation of the main shaft. Odd and even columns alternately perform an addition in one cycle. The sequence of operations for column n {\displaystyle n} is thus:
Steps 1,2,3,4 occur for every odd column, while steps 3,4,1,2 occur for every even column.
While Babbage's original design placed the crank directly on the main shaft, it was later realized that the force required to crank the machine would have been too great for a human to handle comfortably. Therefore, the two models that were built incorporate a 4:1 reduction gear at the crank, and four revolutions of the crank are required to perform one full cycle.
Each iteration creates a new result, and is accomplished in four steps corresponding to four complete turns of the handle shown at the far right in the picture below. The four steps are:
The engine represents negative numbers as ten's complements. Subtraction amounts to addition of a negative number. This works in the same manner that modern computers perform subtraction, known as two's complement.
The principle of a difference engine is Newton's method of divided differences. If the initial value of a polynomial (and of its finite differences) is calculated by some means for some value of X, the difference engine can calculate any number of nearby values, using the method generally known as the method of finite differences. For example, consider the quadratic polynomial
with the goal of tabulating the values p(0), p(1), p(2), p(3), p(4), and so forth. The table below is constructed as follows: the second column contains the values of the polynomial, the third column contains the differences of the two left neighbors in the second column, and the fourth column contains the differences of the two neighbors in the third column:
The numbers in the third values-column are constant. In fact, by starting with any polynomial of degree n, the column number n + 1 will always be constant. This is the crucial fact behind the success of the method.
This table was built from left to right, but it is possible to continue building it from right to left down a diagonal in order to compute more values. To calculate p(5) use the values from the lowest diagonal. Start with the fourth column constant value of 4 and copy it down the column. Then continue the third column by adding 4 to 11 to get 15. Next continue the second column by taking its previous value, 22 and adding the 15 from the third column. Thus p(5) is 22 + 15 = 37. In order to compute p(6), we iterate the same algorithm on the p(5) values: take 4 from the fourth column, add that to the third column's value 15 to get 19, then add that to the second column's value 37 to get 56, which is p(6). This process may be continued ad infinitum. The values of the polynomial are produced without ever having to multiply. A difference engine only needs to be able to add. From one loop to the next, it needs to store 2 numbers—in this example (the last elements in the first and second columns). To tabulate polynomials of degree n, one needs sufficient storage to hold n numbers.
Babbage's difference engine No. 2, finally built in 1991, can hold 8 numbers of 31 decimal digits each and can thus tabulate 7th degree polynomials to that precision. The best machines from Scheutz could store 4 numbers with 15 digits each.
The initial values of columns can be calculated by first manually calculating N consecutive values of the function and by backtracking (i.e. calculating the required differences).
Col 1 0 {\displaystyle 1_{0}} gets the value of the function at the start of computation f ( 0 ) {\displaystyle f(0)} . Col 2 0 {\displaystyle 2_{0}} is the difference between f ( 1 ) {\displaystyle f(1)} and f ( 0 ) {\displaystyle f(0)} ...
If the function to be calculated is a polynomial function, expressed as
the initial values can be calculated directly from the constant coefficients a0, a1,a2, ..., an without calculating any data points. The initial values are thus:
Many commonly used functions are analytic functions, which can be expressed as power series, for example as a Taylor series. The initial values can be calculated to any degree of accuracy; if done correctly the engine will give exact results for first N steps. After that, the engine will only give an approximation of the function.
The Taylor series expresses the function as a sum obtained from its derivatives at one point. For many functions the higher derivatives are trivial to obtain; for instance, the sine function at 0 has values of 0 or ± 1 {\displaystyle \pm 1} for all derivatives. Setting 0 as the start of computation we get the simplified Maclaurin series
The same method of calculating the initial values from the coefficients can be used as for polynomial functions. The polynomial constant coefficients will now have the value
The problem with the methods described above is that errors will accumulate and the series will tend to diverge from the true function. A solution which guarantees a constant maximum error is to use curve fitting. A minimum of N values are calculated evenly spaced along the range of the desired calculations. Using a curve fitting technique like Gaussian reduction an N−1th degree polynomial interpolation of the function is found. With the optimized polynomial, the initial values can be calculated as above. | [
{
"paragraph_id": 0,
"text": "A difference engine is an automatic mechanical calculator designed to tabulate polynomial functions. It was designed in the 1820s, and was first created by Charles Babbage. The name difference engine is derived from the method of divided differences, a way to interpolate or tabulate functions by using a small set of polynomial co-efficients. Some of the most common mathematical functions used in engineering, science and navigation, are built from logarithmic and trigonometric functions, which can be approximated by polynomials, so a difference engine can compute many useful tables.",
"title": ""
},
{
"paragraph_id": 1,
"text": "The notion of a mechanical calculator for mathematical functions can be traced back to the Antikythera mechanism of the 2nd century BC, while early modern examples are attributed to Pascal and Leibniz in the 17th century.",
"title": "History"
},
{
"paragraph_id": 2,
"text": "In 1784 J. H. Müller, an engineer in the Hessian army, devised and built an adding machine and described the basic principles of a difference machine in a book published in 1786 (the first written reference to a difference machine is dated to 1784), but he was unable to obtain funding to progress with the idea.",
"title": "History"
},
{
"paragraph_id": 3,
"text": "Charles Babbage began to construct a small difference engine in c. 1819 and had completed it by 1822 (Difference Engine 0). He announced his invention on 14 June 1822, in a paper to the Royal Astronomical Society, entitled \"Note on the application of machinery to the computation of astronomical and mathematical tables\". This machine used the decimal number system and was powered by cranking a handle. The British government was interested, since producing tables was time-consuming and expensive and they hoped the difference engine would make the task more economical.",
"title": "History"
},
{
"paragraph_id": 4,
"text": "In 1823, the British government gave Babbage £1700 to start work on the project. Although Babbage's design was feasible, the metalworking techniques of the era could not economically make parts in the precision and quantity required. Thus the implementation proved to be much more expensive and doubtful of success than the government's initial estimate. According to the 1830 design for Difference Engine No. 1, it would have about 25,000 parts, weigh 4 tons, and operate on 20-digit numbers by sixth-order differences. In 1832, Babbage and Joseph Clement produced a small working model (one-seventh of the plan), which operated on 6-digit numbers by second-order differences. Lady Byron described seeing the working prototype in 1833: \"We both went to see the thinking machine (or so it seems) last Monday. It raised several Nos. to the 2nd and 3rd powers, and extracted the root of a Quadratic equation.\" Work on the larger engine was suspended in 1833.",
"title": "History"
},
{
"paragraph_id": 5,
"text": "By the time the government abandoned the project in 1842, Babbage had received and spent over £17,000 on development, which still fell short of achieving a working engine. The government valued only the machine's output (economically produced tables), not the development (at unpredictable cost) of the machine itself. Babbage refused to recognize that predicament. Meanwhile, Babbage's attention had moved on to developing an analytical engine, further undermining the government's confidence in the eventual success of the difference engine. By improving the concept as an analytical engine, Babbage had made the difference engine concept obsolete, and the project to implement it an utter failure in the view of the government.",
"title": "History"
},
{
"paragraph_id": 6,
"text": "The incomplete Difference Engine No. 1 was put on display to the public at the 1862 International Exhibition in South Kensington, London.",
"title": "History"
},
{
"paragraph_id": 7,
"text": "Babbage went on to design his much more general analytical engine, but later produced an improved \"Difference Engine No. 2\" design (31-digit numbers and seventh-order differences), between 1846 and 1849. Babbage was able to take advantage of ideas developed for the analytical engine to make the new difference engine calculate more quickly while using fewer parts.",
"title": "History"
},
{
"paragraph_id": 8,
"text": "Inspired by Babbage's difference engine in 1834, Per Georg Scheutz built several experimental models. In 1837 his son Edward proposed to construct a working model in metal, and in 1840 finished the calculating part, capable of calculating series with 5-digit numbers and first-order differences, which was later extended to third-order (1842). In 1843, after adding the printing part, the model was completed.",
"title": "History"
},
{
"paragraph_id": 9,
"text": "In 1851, funded by the government, construction of the larger and improved (15-digit numbers and fourth-order differences) machine began, and finished in 1853. The machine was demonstrated at the World's Fair in Paris, 1855 and then sold in 1856 to the Dudley Observatory in Albany, New York. Delivered in 1857, it was the first printing calculator sold. In 1857 the British government ordered the next Scheutz's difference machine, which was built in 1859. It had the same basic construction as the previous one, weighing about 10 cwt (1,100 lb; 510 kg).",
"title": "History"
},
{
"paragraph_id": 10,
"text": "Martin Wiberg improved Scheutz's construction (c. 1859, his machine has the same capacity as Scheutz's: 15-digit and fourth-order) but used his device only for producing and publishing printed tables (interest tables in 1860, and logarithmic tables in 1875).",
"title": "History"
},
{
"paragraph_id": 11,
"text": "Alfred Deacon of London in c. 1862 produced a small difference engine (20-digit numbers and third-order differences).",
"title": "History"
},
{
"paragraph_id": 12,
"text": "American George B. Grant started working on his calculating machine in 1869, unaware of the works of Babbage and Scheutz (Schentz). One year later (1870) he learned about difference engines and proceeded to design one himself, describing his construction in 1871. In 1874 the Boston Thursday Club raised a subscription for the construction of a large-scale model, which was built in 1876. It could be expanded to enhance precision and weighed about 2,000 pounds (910 kg).",
"title": "History"
},
{
"paragraph_id": 13,
"text": "Christel Hamann built one machine (16-digit numbers and second-order differences) in 1909 for the \"Tables of Bauschinger and Peters\" (\"Logarithmic-Trigonometrical Tables with eight decimal places\"), which was first published in Leipzig in 1910. It weighed about 40 kilograms (88 lb).",
"title": "History"
},
{
"paragraph_id": 14,
"text": "Burroughs Corporation in about 1912 built a machine for the Nautical Almanac Office which was used as a difference engine of second-order. It was later replaced in 1929 by a Burroughs Class 11 (13-digit numbers and second-order differences, or 11-digit numbers and [at least up to] fifth-order differences).",
"title": "History"
},
{
"paragraph_id": 15,
"text": "Alexander John Thompson about 1927 built integrating and differencing machine (13-digit numbers and fifth-order differences) for his table of logarithms \"Logarithmetica britannica\". This machine was composed of four modified Triumphator calculators.",
"title": "History"
},
{
"paragraph_id": 16,
"text": "Leslie Comrie in 1928 described how to use the Brunsviga-Dupla calculating machine as a difference engine of second-order (15-digit numbers). He also noted in 1931 that National Accounting Machine Class 3000 could be used as a difference engine of sixth-order.",
"title": "History"
},
{
"paragraph_id": 17,
"text": "During the 1980s, Allan G. Bromley, an associate professor at the University of Sydney, Australia, studied Babbage's original drawings for the Difference and Analytical Engines at the Science Museum library in London. This work led the Science Museum to construct a working calculating section of difference engine No. 2 from 1985 to 1991, under Doron Swade, the then Curator of Computing. This was to celebrate the 200th anniversary of Babbage's birth in 1991. In 2002, the printer which Babbage originally designed for the difference engine was also completed. The conversion of the original design drawings into drawings suitable for engineering manufacturers' use revealed some minor errors in Babbage's design (possibly introduced as a protection in case the plans were stolen), which had to be corrected. The difference engine and printer were constructed to tolerances achievable with 19th-century technology, resolving a long-standing debate as to whether Babbage's design could have worked using Georgian-era engineering methods. The machine contains 8,000 parts and weighs about 5 tons.",
"title": "History"
},
{
"paragraph_id": 18,
"text": "The printer's primary purpose is to produce stereotype plates for use in printing presses, which it does by pressing type into soft plaster to create a flong. Babbage intended that the Engine's results be conveyed directly to mass printing, having recognized that many errors in previous tables were not the result of human calculating mistakes but from slips in the manual typesetting process. The printer's paper output is mainly a means of checking the engine's performance.",
"title": "History"
},
{
"paragraph_id": 19,
"text": "In addition to funding the construction of the output mechanism for the Science Museum's difference engine, Nathan Myhrvold commissioned the construction of a second complete Difference Engine No. 2, which was on exhibit at the Computer History Museum in Mountain View, California from May 2008 to January 2016. It has since been transferred to Intellectual Ventures in Seattle where it is on display just outside the main lobby.",
"title": "History"
},
{
"paragraph_id": 20,
"text": "The difference engine consists of a number of columns, numbered from 1 to N. The machine is able to store one decimal number in each column. The machine can only add the value of a column n + 1 to column n to produce the new value of n. Column N can only store a constant, column 1 displays (and possibly prints) the value of the calculation on the current iteration.",
"title": "Operation"
},
{
"paragraph_id": 21,
"text": "The engine is programmed by setting initial values to the columns. Column 1 is set to the value of the polynomial at the start of computation. Column 2 is set to a value derived from the first and higher derivatives of the polynomial at the same value of X. Each of the columns from 3 to N is set to a value derived from the ( n − 1 ) {\\displaystyle (n-1)} first and higher derivatives of the polynomial.",
"title": "Operation"
},
{
"paragraph_id": 22,
"text": "In the Babbage design, one iteration (i.e. one full set of addition and carry operations) happens for each rotation of the main shaft. Odd and even columns alternately perform an addition in one cycle. The sequence of operations for column n {\\displaystyle n} is thus:",
"title": "Operation"
},
{
"paragraph_id": 23,
"text": "Steps 1,2,3,4 occur for every odd column, while steps 3,4,1,2 occur for every even column.",
"title": "Operation"
},
{
"paragraph_id": 24,
"text": "While Babbage's original design placed the crank directly on the main shaft, it was later realized that the force required to crank the machine would have been too great for a human to handle comfortably. Therefore, the two models that were built incorporate a 4:1 reduction gear at the crank, and four revolutions of the crank are required to perform one full cycle.",
"title": "Operation"
},
{
"paragraph_id": 25,
"text": "Each iteration creates a new result, and is accomplished in four steps corresponding to four complete turns of the handle shown at the far right in the picture below. The four steps are:",
"title": "Operation"
},
{
"paragraph_id": 26,
"text": "The engine represents negative numbers as ten's complements. Subtraction amounts to addition of a negative number. This works in the same manner that modern computers perform subtraction, known as two's complement.",
"title": "Operation"
},
{
"paragraph_id": 27,
"text": "The principle of a difference engine is Newton's method of divided differences. If the initial value of a polynomial (and of its finite differences) is calculated by some means for some value of X, the difference engine can calculate any number of nearby values, using the method generally known as the method of finite differences. For example, consider the quadratic polynomial",
"title": "Method of differences"
},
{
"paragraph_id": 28,
"text": "with the goal of tabulating the values p(0), p(1), p(2), p(3), p(4), and so forth. The table below is constructed as follows: the second column contains the values of the polynomial, the third column contains the differences of the two left neighbors in the second column, and the fourth column contains the differences of the two neighbors in the third column:",
"title": "Method of differences"
},
{
"paragraph_id": 29,
"text": "The numbers in the third values-column are constant. In fact, by starting with any polynomial of degree n, the column number n + 1 will always be constant. This is the crucial fact behind the success of the method.",
"title": "Method of differences"
},
{
"paragraph_id": 30,
"text": "This table was built from left to right, but it is possible to continue building it from right to left down a diagonal in order to compute more values. To calculate p(5) use the values from the lowest diagonal. Start with the fourth column constant value of 4 and copy it down the column. Then continue the third column by adding 4 to 11 to get 15. Next continue the second column by taking its previous value, 22 and adding the 15 from the third column. Thus p(5) is 22 + 15 = 37. In order to compute p(6), we iterate the same algorithm on the p(5) values: take 4 from the fourth column, add that to the third column's value 15 to get 19, then add that to the second column's value 37 to get 56, which is p(6). This process may be continued ad infinitum. The values of the polynomial are produced without ever having to multiply. A difference engine only needs to be able to add. From one loop to the next, it needs to store 2 numbers—in this example (the last elements in the first and second columns). To tabulate polynomials of degree n, one needs sufficient storage to hold n numbers.",
"title": "Method of differences"
},
{
"paragraph_id": 31,
"text": "Babbage's difference engine No. 2, finally built in 1991, can hold 8 numbers of 31 decimal digits each and can thus tabulate 7th degree polynomials to that precision. The best machines from Scheutz could store 4 numbers with 15 digits each.",
"title": "Method of differences"
},
{
"paragraph_id": 32,
"text": "The initial values of columns can be calculated by first manually calculating N consecutive values of the function and by backtracking (i.e. calculating the required differences).",
"title": "Initial values"
},
{
"paragraph_id": 33,
"text": "Col 1 0 {\\displaystyle 1_{0}} gets the value of the function at the start of computation f ( 0 ) {\\displaystyle f(0)} . Col 2 0 {\\displaystyle 2_{0}} is the difference between f ( 1 ) {\\displaystyle f(1)} and f ( 0 ) {\\displaystyle f(0)} ...",
"title": "Initial values"
},
{
"paragraph_id": 34,
"text": "If the function to be calculated is a polynomial function, expressed as",
"title": "Initial values"
},
{
"paragraph_id": 35,
"text": "the initial values can be calculated directly from the constant coefficients a0, a1,a2, ..., an without calculating any data points. The initial values are thus:",
"title": "Initial values"
},
{
"paragraph_id": 36,
"text": "Many commonly used functions are analytic functions, which can be expressed as power series, for example as a Taylor series. The initial values can be calculated to any degree of accuracy; if done correctly the engine will give exact results for first N steps. After that, the engine will only give an approximation of the function.",
"title": "Initial values"
},
{
"paragraph_id": 37,
"text": "The Taylor series expresses the function as a sum obtained from its derivatives at one point. For many functions the higher derivatives are trivial to obtain; for instance, the sine function at 0 has values of 0 or ± 1 {\\displaystyle \\pm 1} for all derivatives. Setting 0 as the start of computation we get the simplified Maclaurin series",
"title": "Initial values"
},
{
"paragraph_id": 38,
"text": "The same method of calculating the initial values from the coefficients can be used as for polynomial functions. The polynomial constant coefficients will now have the value",
"title": "Initial values"
},
{
"paragraph_id": 39,
"text": "The problem with the methods described above is that errors will accumulate and the series will tend to diverge from the true function. A solution which guarantees a constant maximum error is to use curve fitting. A minimum of N values are calculated evenly spaced along the range of the desired calculations. Using a curve fitting technique like Gaussian reduction an N−1th degree polynomial interpolation of the function is found. With the optimized polynomial, the initial values can be calculated as above.",
"title": "Initial values"
}
] | A difference engine is an automatic mechanical calculator designed to tabulate polynomial functions. It was designed in the 1820s, and was first created by Charles Babbage. The name difference engine is derived from the method of divided differences, a way to interpolate or tabulate functions by using a small set of polynomial co-efficients. Some of the most common mathematical functions used in engineering, science and navigation, are built from logarithmic and trigonometric functions, which can be approximated by polynomials, so a difference engine can compute many useful tables. | 2001-08-24T07:13:57Z | 2023-12-18T11:43:20Z | [
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8,326 | Draupnir | In Norse mythology, Draupnir (Old Norse: [ˈdrɔupnez̠], "the dripper") is a gold ring possessed by the god Odin with the ability to multiply itself: Every ninth night, eight new rings 'drip' from Draupnir, each one of the same size and weight as the original.
Draupnir was forged by the dwarven brothers Brokkr and Eitri (or Sindri). Brokkr and Eitri made this ring as one of a set of three gifts which included Mjöllnir and Gullinbursti. They made these gifts in accordance with a bet Loki made saying that Brokkr and Eitri could not make better gifts than the three made by the Sons of Ivaldi. In the end, Mjöllnir, Thor's hammer, won the contest for Brokkr and Eitri. Loki used a loophole to get out of the wager for his head (the wager was for Loki's head only, but he argued that, to remove his head, they would have to injure his neck, which was not in the bargain) and Brokkr punished him by sealing his lips shut with wire.
The ring was placed by Odin on the funeral pyre of his son Baldr:
Odin laid upon the pyre the gold ring called Draupnir; this quality attended it: that every ninth night there fell from it eight gold rings of equal weight. (from the Gylfaginning).
The ring was subsequently retrieved by Hermóðr. It was offered as a gift by Freyr's servant Skírnir in the wooing of Gerðr, which is described in the poem Skírnismál.
The ring appears in the 2022 video game God of War Ragnarök, where it is used as a base for creating the new weapon of Kratos. The ability of replicating itself is instead used to create spears that can be thrown and explode on command.
A version of the ring appears in the Magic: the Gathering trading card game's 2021 Norse mythology-inspired expansion set Kaldheim. It is represented by the card "Replicating Ring", an artifact that tracks the number of turns it has been in play and eventually creates eight copies of itself after enough turns, or "nights", have passed. | [
{
"paragraph_id": 0,
"text": "In Norse mythology, Draupnir (Old Norse: [ˈdrɔupnez̠], \"the dripper\") is a gold ring possessed by the god Odin with the ability to multiply itself: Every ninth night, eight new rings 'drip' from Draupnir, each one of the same size and weight as the original.",
"title": ""
},
{
"paragraph_id": 1,
"text": "Draupnir was forged by the dwarven brothers Brokkr and Eitri (or Sindri). Brokkr and Eitri made this ring as one of a set of three gifts which included Mjöllnir and Gullinbursti. They made these gifts in accordance with a bet Loki made saying that Brokkr and Eitri could not make better gifts than the three made by the Sons of Ivaldi. In the end, Mjöllnir, Thor's hammer, won the contest for Brokkr and Eitri. Loki used a loophole to get out of the wager for his head (the wager was for Loki's head only, but he argued that, to remove his head, they would have to injure his neck, which was not in the bargain) and Brokkr punished him by sealing his lips shut with wire.",
"title": ""
},
{
"paragraph_id": 2,
"text": "The ring was placed by Odin on the funeral pyre of his son Baldr:",
"title": ""
},
{
"paragraph_id": 3,
"text": "Odin laid upon the pyre the gold ring called Draupnir; this quality attended it: that every ninth night there fell from it eight gold rings of equal weight. (from the Gylfaginning).",
"title": ""
},
{
"paragraph_id": 4,
"text": "The ring was subsequently retrieved by Hermóðr. It was offered as a gift by Freyr's servant Skírnir in the wooing of Gerðr, which is described in the poem Skírnismál.",
"title": ""
},
{
"paragraph_id": 5,
"text": "The ring appears in the 2022 video game God of War Ragnarök, where it is used as a base for creating the new weapon of Kratos. The ability of replicating itself is instead used to create spears that can be thrown and explode on command.",
"title": "In popular culture"
},
{
"paragraph_id": 6,
"text": "A version of the ring appears in the Magic: the Gathering trading card game's 2021 Norse mythology-inspired expansion set Kaldheim. It is represented by the card \"Replicating Ring\", an artifact that tracks the number of turns it has been in play and eventually creates eight copies of itself after enough turns, or \"nights\", have passed.",
"title": "In popular culture"
}
] | In Norse mythology, Draupnir is a gold ring possessed by the god Odin with the ability to multiply itself: Every ninth night, eight new rings 'drip' from Draupnir, each one of the same size and weight as the original. Draupnir was forged by the dwarven brothers Brokkr and Eitri. Brokkr and Eitri made this ring as one of a set of three gifts which included Mjöllnir and Gullinbursti. They made these gifts in accordance with a bet Loki made saying that Brokkr and Eitri could not make better gifts than the three made by the Sons of Ivaldi. In the end, Mjöllnir, Thor's hammer, won the contest for Brokkr and Eitri. Loki used a loophole to get out of the wager for his head and Brokkr punished him by sealing his lips shut with wire. The ring was placed by Odin on the funeral pyre of his son Baldr: The ring was subsequently retrieved by Hermóðr. It was offered as a gift by Freyr's servant Skírnir in the wooing of Gerðr, which is described in the poem Skírnismál. | 2001-08-17T19:25:50Z | 2023-12-18T18:12:17Z | [
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] | https://en.wikipedia.org/wiki/Draupnir |
8,328 | Divergence | In vector calculus, divergence is a vector operator that operates on a vector field, producing a scalar field giving the quantity of the vector field's source at each point. More technically, the divergence represents the volume density of the outward flux of a vector field from an infinitesimal volume around a given point.
As an example, consider air as it is heated or cooled. The velocity of the air at each point defines a vector field. While air is heated in a region, it expands in all directions, and thus the velocity field points outward from that region. The divergence of the velocity field in that region would thus have a positive value. While the air is cooled and thus contracting, the divergence of the velocity has a negative value.
In physical terms, the divergence of a vector field is the extent to which the vector field flux behaves like a source at a given point. It is a local measure of its "outgoingness" – the extent to which there are more of the field vectors exiting from an infinitesimal region of space than entering it. A point at which the flux is outgoing has positive divergence, and is often called a "source" of the field. A point at which the flux is directed inward has negative divergence, and is often called a "sink" of the field. The greater the flux of field through a small surface enclosing a given point, the greater the value of divergence at that point. A point at which there is zero flux through an enclosing surface has zero divergence.
The divergence of a vector field is often illustrated using the simple example of the velocity field of a fluid, a liquid or gas. A moving gas has a velocity, a speed and direction at each point, which can be represented by a vector, so the velocity of the gas forms a vector field. If a gas is heated, it will expand. This will cause a net motion of gas particles outward in all directions. Any closed surface in the gas will enclose gas which is expanding, so there will be an outward flux of gas through the surface. So the velocity field will have positive divergence everywhere. Similarly, if the gas is cooled, it will contract. There will be more room for gas particles in any volume, so the external pressure of the fluid will cause a net flow of gas volume inward through any closed surface. Therefore the velocity field has negative divergence everywhere. In contrast, in a gas at a constant temperature and pressure, the net flux of gas out of any closed surface is zero. The gas may be moving, but the volume rate of gas flowing into any closed surface must equal the volume rate flowing out, so the net flux is zero. Thus the gas velocity has zero divergence everywhere. A field which has zero divergence everywhere is called solenoidal.
If the gas is heated only at one point or small region, or a small tube is introduced which supplies a source of additional gas at one point, the gas there will expand, pushing fluid particles around it outward in all directions. This will cause an outward velocity field throughout the gas, centered on the heated point. Any closed surface enclosing the heated point will have a flux of gas particles passing out of it, so there is positive divergence at that point. However any closed surface not enclosing the point will have a constant density of gas inside, so just as many fluid particles are entering as leaving the volume, thus the net flux out of the volume is zero. Therefore the divergence at any other point is zero.
The divergence of a vector field F(x) at a point x0 is defined as the limit of the ratio of the surface integral of F out of the closed surface of a volume V enclosing x0 to the volume of V, as V shrinks to zero
where |V| is the volume of V, S(V) is the boundary of V, and n ^ {\displaystyle \mathbf {\hat {n}} } is the outward unit normal to that surface. It can be shown that the above limit always converges to the same value for any sequence of volumes that contain x0 and approach zero volume. The result, div F, is a scalar function of x.
Since this definition is coordinate-free, it shows that the divergence is the same in any coordinate system. However it is not often used practically to calculate divergence; when the vector field is given in a coordinate system the coordinate definitions below are much simpler to use.
A vector field with zero divergence everywhere is called solenoidal – in which case any closed surface has no net flux across it.
In three-dimensional Cartesian coordinates, the divergence of a continuously differentiable vector field F = F x i + F y j + F z k {\displaystyle \mathbf {F} =F_{x}\mathbf {i} +F_{y}\mathbf {j} +F_{z}\mathbf {k} } is defined as the scalar-valued function:
Although expressed in terms of coordinates, the result is invariant under rotations, as the physical interpretation suggests. This is because the trace of the Jacobian matrix of an N-dimensional vector field F in N-dimensional space is invariant under any invertible linear transformation.
The common notation for the divergence ∇ · F is a convenient mnemonic, where the dot denotes an operation reminiscent of the dot product: take the components of the ∇ operator (see del), apply them to the corresponding components of F, and sum the results. Because applying an operator is different from multiplying the components, this is considered an abuse of notation.
For a vector expressed in local unit cylindrical coordinates as
where ea is the unit vector in direction a, the divergence is
The use of local coordinates is vital for the validity of the expression. If we consider x the position vector and the functions r(x), θ(x), and z(x), which assign the corresponding global cylindrical coordinate to a vector, in general r ( F ( x ) ) ≠ F r ( x ) {\displaystyle r(\mathbf {F} (\mathbf {x} ))\neq F_{r}(\mathbf {x} )} , θ ( F ( x ) ) ≠ F θ ( x ) {\displaystyle \theta (\mathbf {F} (\mathbf {x} ))\neq F_{\theta }(\mathbf {x} )} , and z ( F ( x ) ) ≠ F z ( x ) {\displaystyle z(\mathbf {F} (\mathbf {x} ))\neq F_{z}(\mathbf {x} )} . In particular, if we consider the identity function F(x) = x, we find that:
In spherical coordinates, with θ the angle with the z axis and φ the rotation around the z axis, and F again written in local unit coordinates, the divergence is
Let A be continuously differentiable second-order tensor field defined as follows:
the divergence in cartesian coordinate system is a first-order tensor field and can be defined in two ways:
and
We have
If tensor is symmetric Aij = Aji then div ( A ) = ∇ ⋅ A {\displaystyle \operatorname {div} (\mathbf {A} )=\nabla \cdot \mathbf {A} } . Because of this, often in the literature the two definitions (and symbols div and ∇ ⋅ {\displaystyle \nabla \cdot } ) are used interchangeably (especially in mechanics equations where tensor symmetry is assumed).
Expressions of ∇ ⋅ A {\displaystyle \nabla \cdot \mathbf {A} } in cylindrical and spherical coordinates are given in the article del in cylindrical and spherical coordinates.
Using Einstein notation we can consider the divergence in general coordinates, which we write as x, …, x, …, x, where n is the number of dimensions of the domain. Here, the upper index refers to the number of the coordinate or component, so x refers to the second component, and not the quantity x squared. The index variable i is used to refer to an arbitrary component, such as x. The divergence can then be written via the Voss-Weyl formula, as:
where ρ {\displaystyle \rho } is the local coefficient of the volume element and F are the components of F = F i e i {\displaystyle \mathbf {F} =F^{i}\mathbf {e} _{i}} with respect to the local unnormalized covariant basis (sometimes written as e i = ∂ x / ∂ x i {\displaystyle \mathbf {e} _{i}=\partial \mathbf {x} /\partial x^{i}} ). The Einstein notation implies summation over i, since it appears as both an upper and lower index.
The volume coefficient ρ is a function of position which depends on the coordinate system. In Cartesian, cylindrical and spherical coordinates, using the same conventions as before, we have ρ = 1, ρ = r and ρ = r sin θ, respectively. The volume can also be expressed as ρ = | det g a b | {\textstyle \rho ={\sqrt {\left|\det g_{ab}\right|}}} , where gab is the metric tensor. The determinant appears because it provides the appropriate invariant definition of the volume, given a set of vectors. Since the determinant is a scalar quantity which doesn't depend on the indices, these can be suppressed, writing ρ = | det g | {\textstyle \rho ={\sqrt {\left|\det g\right|}}} . The absolute value is taken in order to handle the general case where the determinant might be negative, such as in pseudo-Riemannian spaces. The reason for the square-root is a bit subtle: it effectively avoids double-counting as one goes from curved to Cartesian coordinates, and back. The volume (the determinant) can also be understood as the Jacobian of the transformation from Cartesian to curvilinear coordinates, which for n = 3 gives ρ = | ∂ ( x , y , z ) ∂ ( x 1 , x 2 , x 3 ) | {\textstyle \rho =\left|{\frac {\partial (x,y,z)}{\partial (x^{1},x^{2},x^{3})}}\right|} .
Some conventions expect all local basis elements to be normalized to unit length, as was done in the previous sections. If we write e ^ i {\displaystyle {\hat {\mathbf {e} }}_{i}} for the normalized basis, and F ^ i {\displaystyle {\hat {F}}^{i}} for the components of F with respect to it, we have that
using one of the properties of the metric tensor. By dotting both sides of the last equality with the contravariant element e ^ i {\displaystyle {\hat {\mathbf {e} }}^{i}} , we can conclude that F i = F ^ i / g i i {\textstyle F^{i}={\hat {F}}^{i}/{\sqrt {g_{ii}}}} . After substituting, the formula becomes:
See § In curvilinear coordinates for further discussion.
The following properties can all be derived from the ordinary differentiation rules of calculus. Most importantly, the divergence is a linear operator, i.e.,
for all vector fields F and G and all real numbers a and b.
There is a product rule of the following type: if φ is a scalar-valued function and F is a vector field, then
or in more suggestive notation
Another product rule for the cross product of two vector fields F and G in three dimensions involves the curl and reads as follows:
or
The Laplacian of a scalar field is the divergence of the field's gradient:
The divergence of the curl of any vector field (in three dimensions) is equal to zero:
If a vector field F with zero divergence is defined on a ball in R, then there exists some vector field G on the ball with F = curl G. For regions in R more topologically complicated than this, the latter statement might be false (see Poincaré lemma). The degree of failure of the truth of the statement, measured by the homology of the chain complex
serves as a nice quantification of the complicatedness of the underlying region U. These are the beginnings and main motivations of de Rham cohomology.
It can be shown that any stationary flux v(r) that is twice continuously differentiable in R and vanishes sufficiently fast for |r| → ∞ can be decomposed uniquely into an irrotational part E(r) and a source-free part B(r). Moreover, these parts are explicitly determined by the respective source densities (see above) and circulation densities (see the article Curl):
For the irrotational part one has
with
The source-free part, B, can be similarly written: one only has to replace the scalar potential Φ(r) by a vector potential A(r) and the terms −∇Φ by +∇ × A, and the source density div v by the circulation density ∇ × v.
This "decomposition theorem" is a by-product of the stationary case of electrodynamics. It is a special case of the more general Helmholtz decomposition, which works in dimensions greater than three as well.
The divergence of a vector field can be defined in any finite number n {\displaystyle n} of dimensions. If
in a Euclidean coordinate system with coordinates x1, x2, ..., xn, define
In the 1D case, F reduces to a regular function, and the divergence reduces to the derivative.
For any n, the divergence is a linear operator, and it satisfies the "product rule"
for any scalar-valued function φ.
One can express the divergence as a particular case of the exterior derivative, which takes a 2-form to a 3-form in R. Define the current two-form as
It measures the amount of "stuff" flowing through a surface per unit time in a "stuff fluid" of density ρ = 1 dx ∧ dy ∧ dz moving with local velocity F. Its exterior derivative dj is then given by
where ∧ {\displaystyle \wedge } is the wedge product.
Thus, the divergence of the vector field F can be expressed as:
Here the superscript ♭ is one of the two musical isomorphisms, and ⋆ is the Hodge star operator. When the divergence is written in this way, the operator ⋆ d ⋆ {\displaystyle {\star }d{\star }} is referred to as the codifferential. Working with the current two-form and the exterior derivative is usually easier than working with the vector field and divergence, because unlike the divergence, the exterior derivative commutes with a change of (curvilinear) coordinate system.
The appropriate expression is more complicated in curvilinear coordinates. The divergence of a vector field extends naturally to any differentiable manifold of dimension n that has a volume form (or density) μ, e.g. a Riemannian or Lorentzian manifold. Generalising the construction of a two-form for a vector field on R, on such a manifold a vector field X defines an (n − 1)-form j = iX μ obtained by contracting X with μ. The divergence is then the function defined by
The divergence can be defined in terms of the Lie derivative as
This means that the divergence measures the rate of expansion of a unit of volume (a volume element) as it flows with the vector field.
On a pseudo-Riemannian manifold, the divergence with respect to the volume can be expressed in terms of the Levi-Civita connection ∇:
where the second expression is the contraction of the vector field valued 1-form ∇X with itself and the last expression is the traditional coordinate expression from Ricci calculus.
An equivalent expression without using a connection is
where g is the metric and ∂ a {\displaystyle \partial _{a}} denotes the partial derivative with respect to coordinate x. The square-root of the (absolute value of the determinant of the) metric appears because the divergence must be written with the correct conception of the volume. In curvilinear coordinates, the basis vectors are no longer orthonormal; the determinant encodes the correct idea of volume in this case. It appears twice, here, once, so that the X a {\displaystyle X^{a}} can be transformed into "flat space" (where coordinates are actually orthonormal), and once again so that ∂ a {\displaystyle \partial _{a}} is also transformed into "flat space", so that finally, the "ordinary" divergence can be written with the "ordinary" concept of volume in flat space (i.e. unit volume, i.e. one, i.e. not written down). The square-root appears in the denominator, because the derivative transforms in the opposite way (contravariantly) to the vector (which is covariant). This idea of getting to a "flat coordinate system" where local computations can be done in a conventional way is called a vielbein. A different way to see this is to note that the divergence is the codifferential in disguise. That is, the divergence corresponds to the expression ⋆ d ⋆ {\displaystyle \star d\star } with d {\displaystyle d} the differential and ⋆ {\displaystyle \star } the Hodge star. The Hodge star, by its construction, causes the volume form to appear in all of the right places.
Divergence can also be generalised to tensors. In Einstein notation, the divergence of a contravariant vector F is given by
where ∇μ denotes the covariant derivative. In this general setting, the correct formulation of the divergence is to recognize that it is a codifferential; the appropriate properties follow from there.
Equivalently, some authors define the divergence of a mixed tensor by using the musical isomorphism ♯: if T is a (p, q)-tensor (p for the contravariant vector and q for the covariant one), then we define the divergence of T to be the (p, q − 1)-tensor
that is, we take the trace over the first two covariant indices of the covariant derivative. The ♯ {\displaystyle \sharp } symbol refers to the musical isomorphism. | [
{
"paragraph_id": 0,
"text": "In vector calculus, divergence is a vector operator that operates on a vector field, producing a scalar field giving the quantity of the vector field's source at each point. More technically, the divergence represents the volume density of the outward flux of a vector field from an infinitesimal volume around a given point.",
"title": ""
},
{
"paragraph_id": 1,
"text": "As an example, consider air as it is heated or cooled. The velocity of the air at each point defines a vector field. While air is heated in a region, it expands in all directions, and thus the velocity field points outward from that region. The divergence of the velocity field in that region would thus have a positive value. While the air is cooled and thus contracting, the divergence of the velocity has a negative value.",
"title": ""
},
{
"paragraph_id": 2,
"text": "In physical terms, the divergence of a vector field is the extent to which the vector field flux behaves like a source at a given point. It is a local measure of its \"outgoingness\" – the extent to which there are more of the field vectors exiting from an infinitesimal region of space than entering it. A point at which the flux is outgoing has positive divergence, and is often called a \"source\" of the field. A point at which the flux is directed inward has negative divergence, and is often called a \"sink\" of the field. The greater the flux of field through a small surface enclosing a given point, the greater the value of divergence at that point. A point at which there is zero flux through an enclosing surface has zero divergence.",
"title": "Physical interpretation of divergence"
},
{
"paragraph_id": 3,
"text": "The divergence of a vector field is often illustrated using the simple example of the velocity field of a fluid, a liquid or gas. A moving gas has a velocity, a speed and direction at each point, which can be represented by a vector, so the velocity of the gas forms a vector field. If a gas is heated, it will expand. This will cause a net motion of gas particles outward in all directions. Any closed surface in the gas will enclose gas which is expanding, so there will be an outward flux of gas through the surface. So the velocity field will have positive divergence everywhere. Similarly, if the gas is cooled, it will contract. There will be more room for gas particles in any volume, so the external pressure of the fluid will cause a net flow of gas volume inward through any closed surface. Therefore the velocity field has negative divergence everywhere. In contrast, in a gas at a constant temperature and pressure, the net flux of gas out of any closed surface is zero. The gas may be moving, but the volume rate of gas flowing into any closed surface must equal the volume rate flowing out, so the net flux is zero. Thus the gas velocity has zero divergence everywhere. A field which has zero divergence everywhere is called solenoidal.",
"title": "Physical interpretation of divergence"
},
{
"paragraph_id": 4,
"text": "If the gas is heated only at one point or small region, or a small tube is introduced which supplies a source of additional gas at one point, the gas there will expand, pushing fluid particles around it outward in all directions. This will cause an outward velocity field throughout the gas, centered on the heated point. Any closed surface enclosing the heated point will have a flux of gas particles passing out of it, so there is positive divergence at that point. However any closed surface not enclosing the point will have a constant density of gas inside, so just as many fluid particles are entering as leaving the volume, thus the net flux out of the volume is zero. Therefore the divergence at any other point is zero.",
"title": "Physical interpretation of divergence"
},
{
"paragraph_id": 5,
"text": "The divergence of a vector field F(x) at a point x0 is defined as the limit of the ratio of the surface integral of F out of the closed surface of a volume V enclosing x0 to the volume of V, as V shrinks to zero",
"title": "Definition"
},
{
"paragraph_id": 6,
"text": "where |V| is the volume of V, S(V) is the boundary of V, and n ^ {\\displaystyle \\mathbf {\\hat {n}} } is the outward unit normal to that surface. It can be shown that the above limit always converges to the same value for any sequence of volumes that contain x0 and approach zero volume. The result, div F, is a scalar function of x.",
"title": "Definition"
},
{
"paragraph_id": 7,
"text": "Since this definition is coordinate-free, it shows that the divergence is the same in any coordinate system. However it is not often used practically to calculate divergence; when the vector field is given in a coordinate system the coordinate definitions below are much simpler to use.",
"title": "Definition"
},
{
"paragraph_id": 8,
"text": "A vector field with zero divergence everywhere is called solenoidal – in which case any closed surface has no net flux across it.",
"title": "Definition"
},
{
"paragraph_id": 9,
"text": "In three-dimensional Cartesian coordinates, the divergence of a continuously differentiable vector field F = F x i + F y j + F z k {\\displaystyle \\mathbf {F} =F_{x}\\mathbf {i} +F_{y}\\mathbf {j} +F_{z}\\mathbf {k} } is defined as the scalar-valued function:",
"title": "Definition in coordinates"
},
{
"paragraph_id": 10,
"text": "Although expressed in terms of coordinates, the result is invariant under rotations, as the physical interpretation suggests. This is because the trace of the Jacobian matrix of an N-dimensional vector field F in N-dimensional space is invariant under any invertible linear transformation.",
"title": "Definition in coordinates"
},
{
"paragraph_id": 11,
"text": "The common notation for the divergence ∇ · F is a convenient mnemonic, where the dot denotes an operation reminiscent of the dot product: take the components of the ∇ operator (see del), apply them to the corresponding components of F, and sum the results. Because applying an operator is different from multiplying the components, this is considered an abuse of notation.",
"title": "Definition in coordinates"
},
{
"paragraph_id": 12,
"text": "For a vector expressed in local unit cylindrical coordinates as",
"title": "Definition in coordinates"
},
{
"paragraph_id": 13,
"text": "where ea is the unit vector in direction a, the divergence is",
"title": "Definition in coordinates"
},
{
"paragraph_id": 14,
"text": "The use of local coordinates is vital for the validity of the expression. If we consider x the position vector and the functions r(x), θ(x), and z(x), which assign the corresponding global cylindrical coordinate to a vector, in general r ( F ( x ) ) ≠ F r ( x ) {\\displaystyle r(\\mathbf {F} (\\mathbf {x} ))\\neq F_{r}(\\mathbf {x} )} , θ ( F ( x ) ) ≠ F θ ( x ) {\\displaystyle \\theta (\\mathbf {F} (\\mathbf {x} ))\\neq F_{\\theta }(\\mathbf {x} )} , and z ( F ( x ) ) ≠ F z ( x ) {\\displaystyle z(\\mathbf {F} (\\mathbf {x} ))\\neq F_{z}(\\mathbf {x} )} . In particular, if we consider the identity function F(x) = x, we find that:",
"title": "Definition in coordinates"
},
{
"paragraph_id": 15,
"text": "In spherical coordinates, with θ the angle with the z axis and φ the rotation around the z axis, and F again written in local unit coordinates, the divergence is",
"title": "Definition in coordinates"
},
{
"paragraph_id": 16,
"text": "Let A be continuously differentiable second-order tensor field defined as follows:",
"title": "Definition in coordinates"
},
{
"paragraph_id": 17,
"text": "the divergence in cartesian coordinate system is a first-order tensor field and can be defined in two ways:",
"title": "Definition in coordinates"
},
{
"paragraph_id": 18,
"text": "and",
"title": "Definition in coordinates"
},
{
"paragraph_id": 19,
"text": "We have",
"title": "Definition in coordinates"
},
{
"paragraph_id": 20,
"text": "If tensor is symmetric Aij = Aji then div ( A ) = ∇ ⋅ A {\\displaystyle \\operatorname {div} (\\mathbf {A} )=\\nabla \\cdot \\mathbf {A} } . Because of this, often in the literature the two definitions (and symbols div and ∇ ⋅ {\\displaystyle \\nabla \\cdot } ) are used interchangeably (especially in mechanics equations where tensor symmetry is assumed).",
"title": "Definition in coordinates"
},
{
"paragraph_id": 21,
"text": "Expressions of ∇ ⋅ A {\\displaystyle \\nabla \\cdot \\mathbf {A} } in cylindrical and spherical coordinates are given in the article del in cylindrical and spherical coordinates.",
"title": "Definition in coordinates"
},
{
"paragraph_id": 22,
"text": "Using Einstein notation we can consider the divergence in general coordinates, which we write as x, …, x, …, x, where n is the number of dimensions of the domain. Here, the upper index refers to the number of the coordinate or component, so x refers to the second component, and not the quantity x squared. The index variable i is used to refer to an arbitrary component, such as x. The divergence can then be written via the Voss-Weyl formula, as:",
"title": "Definition in coordinates"
},
{
"paragraph_id": 23,
"text": "where ρ {\\displaystyle \\rho } is the local coefficient of the volume element and F are the components of F = F i e i {\\displaystyle \\mathbf {F} =F^{i}\\mathbf {e} _{i}} with respect to the local unnormalized covariant basis (sometimes written as e i = ∂ x / ∂ x i {\\displaystyle \\mathbf {e} _{i}=\\partial \\mathbf {x} /\\partial x^{i}} ). The Einstein notation implies summation over i, since it appears as both an upper and lower index.",
"title": "Definition in coordinates"
},
{
"paragraph_id": 24,
"text": "The volume coefficient ρ is a function of position which depends on the coordinate system. In Cartesian, cylindrical and spherical coordinates, using the same conventions as before, we have ρ = 1, ρ = r and ρ = r sin θ, respectively. The volume can also be expressed as ρ = | det g a b | {\\textstyle \\rho ={\\sqrt {\\left|\\det g_{ab}\\right|}}} , where gab is the metric tensor. The determinant appears because it provides the appropriate invariant definition of the volume, given a set of vectors. Since the determinant is a scalar quantity which doesn't depend on the indices, these can be suppressed, writing ρ = | det g | {\\textstyle \\rho ={\\sqrt {\\left|\\det g\\right|}}} . The absolute value is taken in order to handle the general case where the determinant might be negative, such as in pseudo-Riemannian spaces. The reason for the square-root is a bit subtle: it effectively avoids double-counting as one goes from curved to Cartesian coordinates, and back. The volume (the determinant) can also be understood as the Jacobian of the transformation from Cartesian to curvilinear coordinates, which for n = 3 gives ρ = | ∂ ( x , y , z ) ∂ ( x 1 , x 2 , x 3 ) | {\\textstyle \\rho =\\left|{\\frac {\\partial (x,y,z)}{\\partial (x^{1},x^{2},x^{3})}}\\right|} .",
"title": "Definition in coordinates"
},
{
"paragraph_id": 25,
"text": "Some conventions expect all local basis elements to be normalized to unit length, as was done in the previous sections. If we write e ^ i {\\displaystyle {\\hat {\\mathbf {e} }}_{i}} for the normalized basis, and F ^ i {\\displaystyle {\\hat {F}}^{i}} for the components of F with respect to it, we have that",
"title": "Definition in coordinates"
},
{
"paragraph_id": 26,
"text": "using one of the properties of the metric tensor. By dotting both sides of the last equality with the contravariant element e ^ i {\\displaystyle {\\hat {\\mathbf {e} }}^{i}} , we can conclude that F i = F ^ i / g i i {\\textstyle F^{i}={\\hat {F}}^{i}/{\\sqrt {g_{ii}}}} . After substituting, the formula becomes:",
"title": "Definition in coordinates"
},
{
"paragraph_id": 27,
"text": "See § In curvilinear coordinates for further discussion.",
"title": "Definition in coordinates"
},
{
"paragraph_id": 28,
"text": "The following properties can all be derived from the ordinary differentiation rules of calculus. Most importantly, the divergence is a linear operator, i.e.,",
"title": "Properties"
},
{
"paragraph_id": 29,
"text": "for all vector fields F and G and all real numbers a and b.",
"title": "Properties"
},
{
"paragraph_id": 30,
"text": "There is a product rule of the following type: if φ is a scalar-valued function and F is a vector field, then",
"title": "Properties"
},
{
"paragraph_id": 31,
"text": "or in more suggestive notation",
"title": "Properties"
},
{
"paragraph_id": 32,
"text": "Another product rule for the cross product of two vector fields F and G in three dimensions involves the curl and reads as follows:",
"title": "Properties"
},
{
"paragraph_id": 33,
"text": "or",
"title": "Properties"
},
{
"paragraph_id": 34,
"text": "The Laplacian of a scalar field is the divergence of the field's gradient:",
"title": "Properties"
},
{
"paragraph_id": 35,
"text": "The divergence of the curl of any vector field (in three dimensions) is equal to zero:",
"title": "Properties"
},
{
"paragraph_id": 36,
"text": "If a vector field F with zero divergence is defined on a ball in R, then there exists some vector field G on the ball with F = curl G. For regions in R more topologically complicated than this, the latter statement might be false (see Poincaré lemma). The degree of failure of the truth of the statement, measured by the homology of the chain complex",
"title": "Properties"
},
{
"paragraph_id": 37,
"text": "serves as a nice quantification of the complicatedness of the underlying region U. These are the beginnings and main motivations of de Rham cohomology.",
"title": "Properties"
},
{
"paragraph_id": 38,
"text": "It can be shown that any stationary flux v(r) that is twice continuously differentiable in R and vanishes sufficiently fast for |r| → ∞ can be decomposed uniquely into an irrotational part E(r) and a source-free part B(r). Moreover, these parts are explicitly determined by the respective source densities (see above) and circulation densities (see the article Curl):",
"title": "Decomposition theorem"
},
{
"paragraph_id": 39,
"text": "For the irrotational part one has",
"title": "Decomposition theorem"
},
{
"paragraph_id": 40,
"text": "with",
"title": "Decomposition theorem"
},
{
"paragraph_id": 41,
"text": "The source-free part, B, can be similarly written: one only has to replace the scalar potential Φ(r) by a vector potential A(r) and the terms −∇Φ by +∇ × A, and the source density div v by the circulation density ∇ × v.",
"title": "Decomposition theorem"
},
{
"paragraph_id": 42,
"text": "This \"decomposition theorem\" is a by-product of the stationary case of electrodynamics. It is a special case of the more general Helmholtz decomposition, which works in dimensions greater than three as well.",
"title": "Decomposition theorem"
},
{
"paragraph_id": 43,
"text": "The divergence of a vector field can be defined in any finite number n {\\displaystyle n} of dimensions. If",
"title": "In arbitrary finite dimensions"
},
{
"paragraph_id": 44,
"text": "in a Euclidean coordinate system with coordinates x1, x2, ..., xn, define",
"title": "In arbitrary finite dimensions"
},
{
"paragraph_id": 45,
"text": "In the 1D case, F reduces to a regular function, and the divergence reduces to the derivative.",
"title": "In arbitrary finite dimensions"
},
{
"paragraph_id": 46,
"text": "For any n, the divergence is a linear operator, and it satisfies the \"product rule\"",
"title": "In arbitrary finite dimensions"
},
{
"paragraph_id": 47,
"text": "for any scalar-valued function φ.",
"title": "In arbitrary finite dimensions"
},
{
"paragraph_id": 48,
"text": "One can express the divergence as a particular case of the exterior derivative, which takes a 2-form to a 3-form in R. Define the current two-form as",
"title": "Relation to the exterior derivative"
},
{
"paragraph_id": 49,
"text": "It measures the amount of \"stuff\" flowing through a surface per unit time in a \"stuff fluid\" of density ρ = 1 dx ∧ dy ∧ dz moving with local velocity F. Its exterior derivative dj is then given by",
"title": "Relation to the exterior derivative"
},
{
"paragraph_id": 50,
"text": "where ∧ {\\displaystyle \\wedge } is the wedge product.",
"title": "Relation to the exterior derivative"
},
{
"paragraph_id": 51,
"text": "Thus, the divergence of the vector field F can be expressed as:",
"title": "Relation to the exterior derivative"
},
{
"paragraph_id": 52,
"text": "Here the superscript ♭ is one of the two musical isomorphisms, and ⋆ is the Hodge star operator. When the divergence is written in this way, the operator ⋆ d ⋆ {\\displaystyle {\\star }d{\\star }} is referred to as the codifferential. Working with the current two-form and the exterior derivative is usually easier than working with the vector field and divergence, because unlike the divergence, the exterior derivative commutes with a change of (curvilinear) coordinate system.",
"title": "Relation to the exterior derivative"
},
{
"paragraph_id": 53,
"text": "The appropriate expression is more complicated in curvilinear coordinates. The divergence of a vector field extends naturally to any differentiable manifold of dimension n that has a volume form (or density) μ, e.g. a Riemannian or Lorentzian manifold. Generalising the construction of a two-form for a vector field on R, on such a manifold a vector field X defines an (n − 1)-form j = iX μ obtained by contracting X with μ. The divergence is then the function defined by",
"title": "In curvilinear coordinates"
},
{
"paragraph_id": 54,
"text": "The divergence can be defined in terms of the Lie derivative as",
"title": "In curvilinear coordinates"
},
{
"paragraph_id": 55,
"text": "This means that the divergence measures the rate of expansion of a unit of volume (a volume element) as it flows with the vector field.",
"title": "In curvilinear coordinates"
},
{
"paragraph_id": 56,
"text": "On a pseudo-Riemannian manifold, the divergence with respect to the volume can be expressed in terms of the Levi-Civita connection ∇:",
"title": "In curvilinear coordinates"
},
{
"paragraph_id": 57,
"text": "where the second expression is the contraction of the vector field valued 1-form ∇X with itself and the last expression is the traditional coordinate expression from Ricci calculus.",
"title": "In curvilinear coordinates"
},
{
"paragraph_id": 58,
"text": "An equivalent expression without using a connection is",
"title": "In curvilinear coordinates"
},
{
"paragraph_id": 59,
"text": "where g is the metric and ∂ a {\\displaystyle \\partial _{a}} denotes the partial derivative with respect to coordinate x. The square-root of the (absolute value of the determinant of the) metric appears because the divergence must be written with the correct conception of the volume. In curvilinear coordinates, the basis vectors are no longer orthonormal; the determinant encodes the correct idea of volume in this case. It appears twice, here, once, so that the X a {\\displaystyle X^{a}} can be transformed into \"flat space\" (where coordinates are actually orthonormal), and once again so that ∂ a {\\displaystyle \\partial _{a}} is also transformed into \"flat space\", so that finally, the \"ordinary\" divergence can be written with the \"ordinary\" concept of volume in flat space (i.e. unit volume, i.e. one, i.e. not written down). The square-root appears in the denominator, because the derivative transforms in the opposite way (contravariantly) to the vector (which is covariant). This idea of getting to a \"flat coordinate system\" where local computations can be done in a conventional way is called a vielbein. A different way to see this is to note that the divergence is the codifferential in disguise. That is, the divergence corresponds to the expression ⋆ d ⋆ {\\displaystyle \\star d\\star } with d {\\displaystyle d} the differential and ⋆ {\\displaystyle \\star } the Hodge star. The Hodge star, by its construction, causes the volume form to appear in all of the right places.",
"title": "In curvilinear coordinates"
},
{
"paragraph_id": 60,
"text": "Divergence can also be generalised to tensors. In Einstein notation, the divergence of a contravariant vector F is given by",
"title": "The divergence of tensors"
},
{
"paragraph_id": 61,
"text": "where ∇μ denotes the covariant derivative. In this general setting, the correct formulation of the divergence is to recognize that it is a codifferential; the appropriate properties follow from there.",
"title": "The divergence of tensors"
},
{
"paragraph_id": 62,
"text": "Equivalently, some authors define the divergence of a mixed tensor by using the musical isomorphism ♯: if T is a (p, q)-tensor (p for the contravariant vector and q for the covariant one), then we define the divergence of T to be the (p, q − 1)-tensor",
"title": "The divergence of tensors"
},
{
"paragraph_id": 63,
"text": "that is, we take the trace over the first two covariant indices of the covariant derivative. The ♯ {\\displaystyle \\sharp } symbol refers to the musical isomorphism.",
"title": "The divergence of tensors"
}
] | In vector calculus, divergence is a vector operator that operates on a vector field, producing a scalar field giving the quantity of the vector field's source at each point. More technically, the divergence represents the volume density of the outward flux of a vector field from an infinitesimal volume around a given point. As an example, consider air as it is heated or cooled. The velocity of the air at each point defines a vector field. While air is heated in a region, it expands in all directions, and thus the velocity field points outward from that region. The divergence of the velocity field in that region would thus have a positive value. While the air is cooled and thus contracting, the divergence of the velocity has a negative value. | 2001-08-17T20:35:18Z | 2023-09-04T14:49:05Z | [
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8,334 | December 18 | December 18 is the 352nd day of the year (353rd in leap years) in the Gregorian calendar; 13 days remain until the end of the year. | [
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"text": "December 18 is the 352nd day of the year (353rd in leap years) in the Gregorian calendar; 13 days remain until the end of the year.",
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] | December 18 is the 352nd day of the year in the Gregorian calendar; 13 days remain until the end of the year. | 2001-10-28T14:00:56Z | 2023-12-30T06:45:16Z | [
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8,336 | Decision problem | In computability theory and computational complexity theory, a decision problem is a computational problem that can be posed as a yes–no question of the input values. An example of a decision problem is deciding by means of an algorithm whether a given natural number is prime. Another is the problem "given two numbers x and y, does x evenly divide y?". The answer is either 'yes' or 'no' depending upon the values of x and y. A method for solving a decision problem, given in the form of an algorithm, is called a decision procedure for that problem. A decision procedure for the decision problem "given two numbers x and y, does x evenly divide y?" would give the steps for determining whether x evenly divides y. One such algorithm is long division. If the remainder is zero the answer is 'yes', otherwise it is 'no'. A decision problem which can be solved by an algorithm is called decidable.
Decision problems typically appear in mathematical questions of decidability, that is, the question of the existence of an effective method to determine the existence of some object or its membership in a set; some of the most important problems in mathematics are undecidable.
The field of computational complexity categorizes decidable decision problems by how difficult they are to solve. "Difficult", in this sense, is described in terms of the computational resources needed by the most efficient algorithm for a certain problem. The field of recursion theory, meanwhile, categorizes undecidable decision problems by Turing degree, which is a measure of the noncomputability inherent in any solution.
A decision problem is a yes-or-no question on an infinite set of inputs. It is traditional to define the decision problem as the set of possible inputs together with the set of inputs for which the answer is yes.
These inputs can be natural numbers, but can also be values of some other kind, like binary strings or strings over some other alphabet. The subset of strings for which the problem returns "yes" is a formal language, and often decision problems are defined as formal languages.
Using an encoding such as Gödel numbering, any string can be encoded as a natural number, via which a decision problem can be defined as a subset of the natural numbers. Therefore, the algorithm of a decision problem is to compute the characteristic function of a subset of the natural numbers.
A classic example of a decidable decision problem is the set of prime numbers. It is possible to effectively decide whether a given natural number is prime by testing every possible nontrivial factor. Although much more efficient methods of primality testing are known, the existence of any effective method is enough to establish decidability.
A decision problem is decidable or effectively solvable if the set of inputs (or natural numbers) for which the answer is yes is a recursive set. A problem is partially decidable, semidecidable, solvable, or provable if the set of inputs (or natural numbers) for which the answer is yes is a recursively enumerable set. Problems that are not decidable are undecidable. For those it is not possible to create an algorithm, efficient or otherwise, that solves them.
The halting problem is an important undecidable decision problem; for more examples, see list of undecidable problems.
Decision problems can be ordered according to many-one reducibility and related to feasible reductions such as polynomial-time reductions. A decision problem P is said to be complete for a set of decision problems S if P is a member of S and every problem in S can be reduced to P. Complete decision problems are used in computational complexity theory to characterize complexity classes of decision problems. For example, the Boolean satisfiability problem is complete for the class NP of decision problems under polynomial-time reducibility.
Decision problems are closely related to function problems, which can have answers that are more complex than a simple 'yes' or 'no'. A corresponding function problem is "given two numbers x and y, what is x divided by y?".
A function problem consists of a partial function f; the informal "problem" is to compute the values of f on the inputs for which it is defined.
Every function problem can be turned into a decision problem; the decision problem is just the graph of the associated function. (The graph of a function f is the set of pairs (x,y) such that f(x) = y.) If this decision problem were effectively solvable then the function problem would be as well. This reduction does not respect computational complexity, however. For example, it is possible for the graph of a function to be decidable in polynomial time (in which case running time is computed as a function of the pair (x,y)) when the function is not computable in polynomial time (in which case running time is computed as a function of x alone). The function f(x) = 2 has this property.
Every decision problem can be converted into the function problem of computing the characteristic function of the set associated to the decision problem. If this function is computable then the associated decision problem is decidable. However, this reduction is more liberal than the standard reduction used in computational complexity (sometimes called polynomial-time many-one reduction); for example, the complexity of the characteristic functions of an NP-complete problem and its co-NP-complete complement is exactly the same even though the underlying decision problems may not be considered equivalent in some typical models of computation.
Unlike decision problems, for which there is only one correct answer for each input, optimization problems are concerned with finding the best answer to a particular input. Optimization problems arise naturally in many applications, such as the traveling salesman problem and many questions in linear programming.
Function and optimization problems are often transformed into decision problems by considering the question of whether the output is equal to or less than or equal to a given value. This allows the complexity of the corresponding decision problem to be studied; and in many cases the original function or optimization problem can be solved by solving its corresponding decision problem. For example, in the traveling salesman problem, the optimization problem is to produce a tour with minimal weight. The associated decision problem is: for each N, to decide whether the graph has any tour with weight less than N. By repeatedly answering the decision problem, it is possible to find the minimal weight of a tour.
Because the theory of decision problems is very well developed, research in complexity theory has typically focused on decision problems. Optimization problems themselves are still of interest in computability theory, as well as in fields such as operations research. | [
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"text": "A decision problem is a yes-or-no question on an infinite set of inputs. It is traditional to define the decision problem as the set of possible inputs together with the set of inputs for which the answer is yes.",
"title": "Definition"
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"title": "Definition"
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"text": "Using an encoding such as Gödel numbering, any string can be encoded as a natural number, via which a decision problem can be defined as a subset of the natural numbers. Therefore, the algorithm of a decision problem is to compute the characteristic function of a subset of the natural numbers.",
"title": "Definition"
},
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"paragraph_id": 6,
"text": "A classic example of a decidable decision problem is the set of prime numbers. It is possible to effectively decide whether a given natural number is prime by testing every possible nontrivial factor. Although much more efficient methods of primality testing are known, the existence of any effective method is enough to establish decidability.",
"title": "Examples"
},
{
"paragraph_id": 7,
"text": "A decision problem is decidable or effectively solvable if the set of inputs (or natural numbers) for which the answer is yes is a recursive set. A problem is partially decidable, semidecidable, solvable, or provable if the set of inputs (or natural numbers) for which the answer is yes is a recursively enumerable set. Problems that are not decidable are undecidable. For those it is not possible to create an algorithm, efficient or otherwise, that solves them.",
"title": "Decidability"
},
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"text": "The halting problem is an important undecidable decision problem; for more examples, see list of undecidable problems.",
"title": "Decidability"
},
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"paragraph_id": 9,
"text": "Decision problems can be ordered according to many-one reducibility and related to feasible reductions such as polynomial-time reductions. A decision problem P is said to be complete for a set of decision problems S if P is a member of S and every problem in S can be reduced to P. Complete decision problems are used in computational complexity theory to characterize complexity classes of decision problems. For example, the Boolean satisfiability problem is complete for the class NP of decision problems under polynomial-time reducibility.",
"title": "Complete problems"
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"text": "Decision problems are closely related to function problems, which can have answers that are more complex than a simple 'yes' or 'no'. A corresponding function problem is \"given two numbers x and y, what is x divided by y?\".",
"title": "Function problems"
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"text": "A function problem consists of a partial function f; the informal \"problem\" is to compute the values of f on the inputs for which it is defined.",
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"text": "Every function problem can be turned into a decision problem; the decision problem is just the graph of the associated function. (The graph of a function f is the set of pairs (x,y) such that f(x) = y.) If this decision problem were effectively solvable then the function problem would be as well. This reduction does not respect computational complexity, however. For example, it is possible for the graph of a function to be decidable in polynomial time (in which case running time is computed as a function of the pair (x,y)) when the function is not computable in polynomial time (in which case running time is computed as a function of x alone). The function f(x) = 2 has this property.",
"title": "Function problems"
},
{
"paragraph_id": 13,
"text": "Every decision problem can be converted into the function problem of computing the characteristic function of the set associated to the decision problem. If this function is computable then the associated decision problem is decidable. However, this reduction is more liberal than the standard reduction used in computational complexity (sometimes called polynomial-time many-one reduction); for example, the complexity of the characteristic functions of an NP-complete problem and its co-NP-complete complement is exactly the same even though the underlying decision problems may not be considered equivalent in some typical models of computation.",
"title": "Function problems"
},
{
"paragraph_id": 14,
"text": "Unlike decision problems, for which there is only one correct answer for each input, optimization problems are concerned with finding the best answer to a particular input. Optimization problems arise naturally in many applications, such as the traveling salesman problem and many questions in linear programming.",
"title": "Optimization problems"
},
{
"paragraph_id": 15,
"text": "Function and optimization problems are often transformed into decision problems by considering the question of whether the output is equal to or less than or equal to a given value. This allows the complexity of the corresponding decision problem to be studied; and in many cases the original function or optimization problem can be solved by solving its corresponding decision problem. For example, in the traveling salesman problem, the optimization problem is to produce a tour with minimal weight. The associated decision problem is: for each N, to decide whether the graph has any tour with weight less than N. By repeatedly answering the decision problem, it is possible to find the minimal weight of a tour.",
"title": "Optimization problems"
},
{
"paragraph_id": 16,
"text": "Because the theory of decision problems is very well developed, research in complexity theory has typically focused on decision problems. Optimization problems themselves are still of interest in computability theory, as well as in fields such as operations research.",
"title": "Optimization problems"
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] | In computability theory and computational complexity theory, a decision problem is a computational problem that can be posed as a yes–no question of the input values. An example of a decision problem is deciding by means of an algorithm whether a given natural number is prime. Another is the problem "given two numbers x and y, does x evenly divide y?". The answer is either 'yes' or 'no' depending upon the values of x and y. A method for solving a decision problem, given in the form of an algorithm, is called a decision procedure for that problem. A decision procedure for the decision problem "given two numbers x and y, does x evenly divide y?" would give the steps for determining whether x evenly divides y. One such algorithm is long division. If the remainder is zero the answer is 'yes', otherwise it is 'no'. A decision problem which can be solved by an algorithm is called decidable. Decision problems typically appear in mathematical questions of decidability, that is, the question of the existence of an effective method to determine the existence of some object or its membership in a set; some of the most important problems in mathematics are undecidable. The field of computational complexity categorizes decidable decision problems by how difficult they are to solve. "Difficult", in this sense, is described in terms of the computational resources needed by the most efficient algorithm for a certain problem. The field of recursion theory, meanwhile, categorizes undecidable decision problems by Turing degree, which is a measure of the noncomputability inherent in any solution. | 2001-08-25T18:23:12Z | 2023-10-31T02:02:42Z | [
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8,339 | Domain Name System | The Domain Name System (DNS) is a hierarchical and distributed naming system for computers, services, and other resources in the Internet or other Internet Protocol (IP) networks. It associates various information with domain names (identification strings) assigned to each of the associated entities. Most prominently, it translates readily memorized domain names to the numerical IP addresses needed for locating and identifying computer services and devices with the underlying network protocols. The Domain Name System has been an essential component of the functionality of the Internet since 1985.
The Domain Name System delegates the responsibility of assigning domain names and mapping those names to Internet resources by designating authoritative name servers for each domain. Network administrators may delegate authority over sub-domains of their allocated name space to other name servers. This mechanism provides distributed and fault-tolerant service and was designed to avoid a single large central database. In addition, the DNS specifies the technical functionality of the database service that is at its core. It defines the DNS protocol, a detailed specification of the data structures and data communication exchanges used in the DNS, as part of the Internet protocol suite.
The Internet maintains two principal namespaces, the domain name hierarchy and the IP address spaces. The Domain Name System maintains the domain name hierarchy and provides translation services between it and the address spaces. Internet name servers and a communication protocol implement the Domain Name System. A DNS name server is a server that stores the DNS records for a domain; a DNS name server responds with answers to queries against its database.
The most common types of records stored in the DNS database are for start of authority (SOA), IP addresses (A and AAAA), SMTP mail exchangers (MX), name servers (NS), pointers for reverse DNS lookups (PTR), and domain name aliases (CNAME). Although not intended to be a general purpose database, DNS has been expanded over time to store records for other types of data for either automatic lookups, such as DNSSEC records, or for human queries such as responsible person (RP) records. As a general purpose database, the DNS has also been used in combating unsolicited email (spam) by storing a real-time blackhole list (RBL). The DNS database is traditionally stored in a structured text file, the zone file, but other database systems are common.
The Domain Name System originally used the User Datagram Protocol (UDP) as transport over IP. Reliability, security, and privacy concerns spawned the use of the Transmission Control Protocol (TCP) as well as numerous other protocol developments.
An often-used analogy to explain the DNS is that it serves as the phone book for the Internet by translating human-friendly computer hostnames into IP addresses. For example, the hostname www.example.com within the domain name example.com translates to the addresses 93.184.216.34 (IPv4) and 2606:2800:220:1:248:1893:25c8:1946 (IPv6). The DNS can be quickly and transparently updated, allowing a service's location on the network to change without affecting the end users, who continue to use the same hostname. Users take advantage of this when they use meaningful Uniform Resource Locators (URLs) and e-mail addresses without having to know how the computer actually locates the services.
An important and ubiquitous function of the DNS is its central role in distributed Internet services such as cloud services and content delivery networks. When a user accesses a distributed Internet service using a URL, the domain name of the URL is translated to the IP address of a server that is proximal to the user. The key functionality of the DNS exploited here is that different users can simultaneously receive different translations for the same domain name, a key point of divergence from a traditional phone-book view of the DNS. This process of using the DNS to assign proximal servers to users is key to providing faster and more reliable responses on the Internet and is widely used by most major Internet services.
The DNS reflects the structure of administrative responsibility on the Internet. Each subdomain is a zone of administrative autonomy delegated to a manager. For zones operated by a registry, administrative information is often complemented by the registry's RDAP and WHOIS services. That data can be used to gain insight on, and track responsibility for, a given host on the Internet.
Using a simpler, more memorable name in place of a host's numerical address dates back to the ARPANET era. The Stanford Research Institute (now SRI International) maintained a text file named HOSTS.TXT that mapped host names to the numerical addresses of computers on the ARPANET. Elizabeth Feinler developed and maintained the first ARPANET directory. Maintenance of numerical addresses, called the Assigned Numbers List, was handled by Jon Postel at the University of Southern California's Information Sciences Institute (ISI), whose team worked closely with SRI.
Addresses were assigned manually. Computers, including their hostnames and addresses, were added to the primary file by contacting the SRI Network Information Center (NIC), directed by Feinler, via telephone during business hours. Later, Feinler set up a WHOIS directory on a server in the NIC for retrieval of information about resources, contacts, and entities. She and her team developed the concept of domains. Feinler suggested that domains should be based on the location of the physical address of the computer. Computers at educational institutions would have the domain edu, for example. She and her team managed the Host Naming Registry from 1972 to 1989.
By the early 1980s, maintaining a single, centralized host table had become slow and unwieldy and the emerging network required an automated naming system to address technical and personnel issues. Postel directed the task of forging a compromise between five competing proposals of solutions to Paul Mockapetris. Mockapetris instead created the Domain Name System in 1983 while at the University of Southern California.
The Internet Engineering Task Force published the original specifications in RFC 882 and RFC 883 in November 1983. These were updated in RFC 973 in January 1986.
In 1984, four UC Berkeley students, Douglas Terry, Mark Painter, David Riggle, and Songnian Zhou, wrote the first Unix name server implementation for the Berkeley Internet Name Domain, commonly referred to as BIND. In 1985, Kevin Dunlap of DEC substantially revised the DNS implementation. Mike Karels, Phil Almquist, and Paul Vixie then took over BIND maintenance. Internet Systems Consortium was founded in 1994 by Rick Adams, Paul Vixie, and Carl Malamud, expressly to provide a home for BIND development and maintenance. BIND versions from 4.9.3 onward were developed and maintained by ISC, with support provided by ISC's sponsors. As co-architects/programmers, Bob Halley and Paul Vixie released the first production-ready version of BIND version 8 in May 1997. Since 2000, over 43 different core developers have worked on BIND.
In November 1987, RFC 1034 and RFC 1035 superseded the 1983 DNS specifications. Several additional Request for Comments have proposed extensions to the core DNS protocols.
The domain name space consists of a tree data structure. Each node or leaf in the tree has a label and zero or more resource records (RR), which hold information associated with the domain name. The domain name itself consists of the label, concatenated with the name of its parent node on the right, separated by a dot.
The tree sub-divides into zones beginning at the root zone. A DNS zone may consist of as many domains and sub domains as the zone manager chooses. DNS can also be partitioned according to class where the separate classes can be thought of as an array of parallel namespace trees.
Administrative responsibility for any zone may be divided by creating additional zones. Authority over the new zone is said to be delegated to a designated name server. The parent zone ceases to be authoritative for the new zone.
The definitive descriptions of the rules for forming domain names appear in RFC 1035, RFC 1123, RFC 2181, and RFC 5892. A domain name consists of one or more parts, technically called labels, that are conventionally concatenated, and delimited by dots, such as example.com.
The right-most label conveys the top-level domain; for example, the domain name www.example.com belongs to the top-level domain com.
The hierarchy of domains descends from right to left; each label to the left specifies a subdivision, or subdomain of the domain to the right. For example, the label example specifies a subdomain of the com domain, and www is a subdomain of example.com. This tree of subdivisions may have up to 127 levels.
A label may contain zero to 63 characters. The null label, of length zero, is reserved for the root zone. The full domain name may not exceed the length of 253 characters in its textual representation. In the internal binary representation of the DNS the maximum length requires 255 octets of storage, as it also stores the length of the name.
Although no technical limitation exists to prevent domain name labels using any character which is representable by an octet, hostnames use a preferred format and character set. The characters allowed in labels are a subset of the ASCII character set, consisting of characters a through z, A through Z, digits 0 through 9, and hyphen. This rule is known as the LDH rule (letters, digits, hyphen). Domain names are interpreted in case-independent manner. Labels may not start or end with a hyphen. An additional rule requires that top-level domain names should not be all-numeric.
The limited set of ASCII characters permitted in the DNS prevented the representation of names and words of many languages in their native alphabets or scripts. To make this possible, ICANN approved the Internationalizing Domain Names in Applications (IDNA) system, by which user applications, such as web browsers, map Unicode strings into the valid DNS character set using Punycode. In 2009 ICANN approved the installation of internationalized domain name country code top-level domains (ccTLDs). In addition, many registries of the existing top-level domain names (TLDs) have adopted the IDNA system, guided by RFC 5890, RFC 5891, RFC 5892, RFC 5893.
The Domain Name System is maintained by a distributed database system, which uses the client–server model. The nodes of this database are the name servers. Each domain has at least one authoritative DNS server that publishes information about that domain and the name servers of any domains subordinate to it. The top of the hierarchy is served by the root name servers, the servers to query when looking up (resolving) a TLD.
An authoritative name server is a name server that only gives answers to DNS queries from data that have been configured by an original source, for example, the domain administrator or by dynamic DNS methods, in contrast to answers obtained via a query to another name server that only maintains a cache of data.
An authoritative name server can either be a primary server or a secondary server. Historically the terms master/slave and primary/secondary were sometimes used interchangeably but the current practice is to use the latter form. A primary server is a server that stores the original copies of all zone records. A secondary server uses a special automatic updating mechanism in the DNS protocol in communication with its primary to maintain an identical copy of the primary records.
Every DNS zone must be assigned a set of authoritative name servers. This set of servers is stored in the parent domain zone with name server (NS) records.
An authoritative server indicates its status of supplying definitive answers, deemed authoritative, by setting a protocol flag, called the "Authoritative Answer" (AA) bit in its responses. This flag is usually reproduced prominently in the output of DNS administration query tools, such as dig, to indicate that the responding name server is an authority for the domain name in question.
When a name server is designated as the authoritative server for a domain name for which it does not have authoritative data, it presents a type of error called a "lame delegation" or "lame response".
Domain name resolvers determine the domain name servers responsible for the domain name in question by a sequence of queries starting with the right-most (top-level) domain label.
For proper operation of its domain name resolver, a network host is configured with an initial cache (hints) of the known addresses of the root name servers. The hints are updated periodically by an administrator by retrieving a dataset from a reliable source.
Assuming the resolver has no cached records to accelerate the process, the resolution process starts with a query to one of the root servers. In typical operation, the root servers do not answer directly, but respond with a referral to more authoritative servers, e.g., a query for "www.wikipedia.org" is referred to the org servers. The resolver now queries the servers referred to, and iteratively repeats this process until it receives an authoritative answer. The diagram illustrates this process for the host that is named by the fully qualified domain name "www.wikipedia.org".
This mechanism would place a large traffic burden on the root servers, if every resolution on the Internet required starting at the root. In practice caching is used in DNS servers to off-load the root servers, and as a result, root name servers actually are involved in only a relatively small fraction of all requests.
In theory, authoritative name servers are sufficient for the operation of the Internet. However, with only authoritative name servers operating, every DNS query must start with recursive queries at the root zone of the Domain Name System and each user system would have to implement resolver software capable of recursive operation.
To improve efficiency, reduce DNS traffic across the Internet, and increase performance in end-user applications, the Domain Name System supports DNS cache servers which store DNS query results for a period of time determined in the configuration (time-to-live) of the domain name record in question. Typically, such caching DNS servers also implement the recursive algorithm necessary to resolve a given name starting with the DNS root through to the authoritative name servers of the queried domain. With this function implemented in the name server, user applications gain efficiency in design and operation.
The combination of DNS caching and recursive functions in a name server is not mandatory; the functions can be implemented independently in servers for special purposes.
Internet service providers typically provide recursive and caching name servers for their customers. In addition, many home networking routers implement DNS caches and recursion to improve efficiency in the local network.
The client side of the DNS is called a DNS resolver. A resolver is responsible for initiating and sequencing the queries that ultimately lead to a full resolution (translation) of the resource sought, e.g., translation of a domain name into an IP address. DNS resolvers are classified by a variety of query methods, such as recursive, non-recursive, and iterative. A resolution process may use a combination of these methods.
In a non-recursive query, a DNS resolver queries a DNS server that provides a record either for which the server is authoritative, or it provides a partial result without querying other servers. In case of a caching DNS resolver, the non-recursive query of its local DNS cache delivers a result and reduces the load on upstream DNS servers by caching DNS resource records for a period of time after an initial response from upstream DNS servers.
In a recursive query, a DNS resolver queries a single DNS server, which may in turn query other DNS servers on behalf of the requester. For example, a simple stub resolver running on a home router typically makes a recursive query to the DNS server run by the user's ISP. A recursive query is one for which the DNS server answers the query completely by querying other name servers as needed. In typical operation, a client issues a recursive query to a caching recursive DNS server, which subsequently issues non-recursive queries to determine the answer and send a single answer back to the client. The resolver, or another DNS server acting recursively on behalf of the resolver, negotiates use of recursive service using bits in the query headers. DNS servers are not required to support recursive queries.
The iterative query procedure is a process in which a DNS resolver queries a chain of one or more DNS servers. Each server refers the client to the next server in the chain, until the current server can fully resolve the request. For example, a possible resolution of www.example.com would query a global root server, then a "com" server, and finally an "example.com" server.
Name servers in delegations are identified by name, rather than by IP address. This means that a resolving name server must issue another DNS request to find out the IP address of the server to which it has been referred. If the name given in the delegation is a subdomain of the domain for which the delegation is being provided, there is a circular dependency.
In this case, the name server providing the delegation must also provide one or more IP addresses for the authoritative name server mentioned in the delegation. This information is called glue. The delegating name server provides this glue in the form of records in the additional section of the DNS response, and provides the delegation in the authority section of the response. A glue record is a combination of the name server and IP address.
For example, if the authoritative name server for example.org is ns1.example.org, a computer trying to resolve www.example.org first resolves ns1.example.org. As ns1 is contained in example.org, this requires resolving example.org first, which presents a circular dependency. To break the dependency, the name server for the top level domain org includes glue along with the delegation for example.org. The glue records are address records that provide IP addresses for ns1.example.org. The resolver uses one or more of these IP addresses to query one of the domain's authoritative servers, which allows it to complete the DNS query.
A standard practice in implementing name resolution in applications is to reduce the load on the Domain Name System servers by caching results locally, or in intermediate resolver hosts. Results obtained from a DNS request are always associated with the time to live (TTL), an expiration time after which the results must be discarded or refreshed. The TTL is set by the administrator of the authoritative DNS server. The period of validity may vary from a few seconds to days or even weeks.
As a result of this distributed caching architecture, changes to DNS records do not propagate throughout the network immediately, but require all caches to expire and to be refreshed after the TTL. RFC 1912 conveys basic rules for determining appropriate TTL values.
Some resolvers may override TTL values, as the protocol supports caching for up to sixty-eight years or no caching at all. Negative caching, i.e. the caching of the fact of non-existence of a record, is determined by name servers authoritative for a zone which must include the Start of Authority (SOA) record when reporting no data of the requested type exists. The value of the minimum field of the SOA record and the TTL of the SOA itself is used to establish the TTL for the negative answer.
A reverse DNS lookup is a query of the DNS for domain names when the IP address is known. Multiple domain names may be associated with an IP address. The DNS stores IP addresses in the form of domain names as specially formatted names in pointer (PTR) records within the infrastructure top-level domain arpa. For IPv4, the domain is in-addr.arpa. For IPv6, the reverse lookup domain is ip6.arpa. The IP address is represented as a name in reverse-ordered octet representation for IPv4, and reverse-ordered nibble representation for IPv6.
When performing a reverse lookup, the DNS client converts the address into these formats before querying the name for a PTR record following the delegation chain as for any DNS query. For example, assuming the IPv4 address 208.80.152.2 is assigned to Wikimedia, it is represented as a DNS name in reverse order: 2.152.80.208.in-addr.arpa. When the DNS resolver gets a pointer (PTR) request, it begins by querying the root servers, which point to the servers of American Registry for Internet Numbers (ARIN) for the 208.in-addr.arpa zone. ARIN's servers delegate 152.80.208.in-addr.arpa to Wikimedia to which the resolver sends another query for 2.152.80.208.in-addr.arpa, which results in an authoritative response.
Users generally do not communicate directly with a DNS resolver. Instead DNS resolution takes place transparently in applications such as web browsers, e-mail clients, and other Internet applications. When an application makes a request that requires a domain name lookup, such programs send a resolution request to the DNS resolver in the local operating system, which in turn handles the communications required.
The DNS resolver will almost invariably have a cache (see above) containing recent lookups. If the cache can provide the answer to the request, the resolver will return the value in the cache to the program that made the request. If the cache does not contain the answer, the resolver will send the request to one or more designated DNS servers. In the case of most home users, the Internet service provider to which the machine connects will usually supply this DNS server: such a user will either have configured that server's address manually or allowed DHCP to set it; however, where systems administrators have configured systems to use their own DNS servers, their DNS resolvers point to separately maintained name servers of the organization. In any event, the name server thus queried will follow the process outlined above, until it either successfully finds a result or does not. It then returns its results to the DNS resolver; assuming it has found a result, the resolver duly caches that result for future use, and hands the result back to the software which initiated the request.
Some large ISPs have configured their DNS servers to violate rules, such as by disobeying TTLs, or by indicating that a domain name does not exist just because one of its name servers does not respond.
Some applications such as web browsers maintain an internal DNS cache to avoid repeated lookups via the network. This practice can add extra difficulty when debugging DNS issues as it obscures the history of such data. These caches typically use very short caching times on the order of one minute.
Internet Explorer represents a notable exception: versions up to IE 3.x cache DNS records for 24 hours by default. Internet Explorer 4.x and later versions (up to IE 8) decrease the default timeout value to half an hour, which may be changed by modifying the default configuration.
When Google Chrome detects issues with the DNS server it displays a specific error message.
The Domain Name System includes several other functions and features.
Hostnames and IP addresses are not required to match in a one-to-one relationship. Multiple hostnames may correspond to a single IP address, which is useful in virtual hosting, in which many web sites are served from a single host. Alternatively, a single hostname may resolve to many IP addresses to facilitate fault tolerance and load distribution to multiple server instances across an enterprise or the global Internet.
DNS serves other purposes in addition to translating names to IP addresses. For instance, mail transfer agents use DNS to find the best mail server to deliver e-mail: An MX record provides a mapping between a domain and a mail exchanger; this can provide an additional layer of fault tolerance and load distribution.
The DNS is used for efficient storage and distribution of IP addresses of blacklisted email hosts. A common method is to place the IP address of the subject host into the sub-domain of a higher level domain name, and to resolve that name to a record that indicates a positive or a negative indication.
For example:
E-mail servers can query blacklist.example to find out if a specific host connecting to them is in the blacklist. Many of such blacklists, either subscription-based or free of cost, are available for use by email administrators and anti-spam software.
To provide resilience in the event of computer or network failure, multiple DNS servers are usually provided for coverage of each domain. At the top level of global DNS, thirteen groups of root name servers exist, with additional "copies" of them distributed worldwide via anycast addressing.
Dynamic DNS (DDNS) updates a DNS server with a client IP address on-the-fly, for example, when moving between ISPs or mobile hot spots, or when the IP address changes administratively.
The DNS protocol uses two types of DNS messages, queries and responses; both have the same format. Each message consists of a header and four sections: question, answer, authority, and an additional space. A header field (flags) controls the content of these four sections.
The header section consists of the following fields: Identification, Flags, Number of questions, Number of answers, Number of authority resource records (RRs), and Number of additional RRs. Each field is 16 bits long, and appears in the order given. The identification field is used to match responses with queries. The flag field consists of sub-fields as follows:
After the flag, the header ends with four 16-bit integers which contain the number of records in each of the sections that follow, in the same order.
The question section has a simpler format than the resource record format used in the other sections. Each question record (there is usually just one in the section) contains the following fields:
The domain name is broken into discrete labels which are concatenated; each label is prefixed by the length of that label.
The Domain Name System specifies a database of information elements for network resources. The types of information elements are categorized and organized with a list of DNS record types, the resource records (RRs). Each record has a type (name and number), an expiration time (time to live), a class, and type-specific data. Resource records of the same type are described as a resource record set (RRset), having no special ordering. DNS resolvers return the entire set upon query, but servers may implement round-robin ordering to achieve load balancing. In contrast, the Domain Name System Security Extensions (DNSSEC) work on the complete set of resource record in canonical order.
When sent over an Internet Protocol network, all records use the common format specified in RFC 1035:
NAME is the fully qualified domain name of the node in the tree . On the wire, the name may be shortened using label compression where ends of domain names mentioned earlier in the packet can be substituted for the end of the current domain name.
TYPE is the record type. It indicates the format of the data and it gives a hint of its intended use. For example, the A record is used to translate from a domain name to an IPv4 address, the NS record lists which name servers can answer lookups on a DNS zone, and the MX record specifies the mail server used to handle mail for a domain specified in an e-mail address.
RDATA is data of type-specific relevance, such as the IP address for address records, or the priority and hostname for MX records. Well known record types may use label compression in the RDATA field, but "unknown" record types must not (RFC 3597).
The CLASS of a record is set to IN (for Internet) for common DNS records involving Internet hostnames, servers, or IP addresses. In addition, the classes Chaos (CH) and Hesiod (HS) exist. Each class is an independent name space with potentially different delegations of DNS zones.
In addition to resource records defined in a zone file, the domain name system also defines several request types that are used only in communication with other DNS nodes (on the wire), such as when performing zone transfers (AXFR/IXFR) or for EDNS (OPT).
The domain name system supports wildcard DNS records which specify names that start with the asterisk label, '*', e.g., *.example. DNS records belonging to wildcard domain names specify rules for generating resource records within a single DNS zone by substituting whole labels with matching components of the query name, including any specified descendants. For example, in the following configuration, the DNS zone x.example specifies that all subdomains, including subdomains of subdomains, of x.example use the mail exchanger (MX) a.x.example. The A record for a.x.example is needed to specify the mail exchanger IP address. As this has the result of excluding this domain name and its subdomains from the wildcard matches, an additional MX record for the subdomain a.x.example, as well as a wildcarded MX record for all of its subdomains, must also be defined in the DNS zone.
The role of wildcard records was refined in RFC 4592, because the original definition in RFC 1034 was incomplete and resulted in misinterpretations by implementers.
The original DNS protocol had limited provisions for extension with new features. In 1999, Paul Vixie published in RFC 2671 (superseded by RFC 6891) an extension mechanism, called Extension Mechanisms for DNS (EDNS) that introduced optional protocol elements without increasing overhead when not in use. This was accomplished through the OPT pseudo-resource record that only exists in wire transmissions of the protocol, but not in any zone files. Initial extensions were also suggested (EDNS0), such as increasing the DNS message size in UDP datagrams.
Dynamic DNS updates use the UPDATE DNS opcode to add or remove resource records dynamically from a zone database maintained on an authoritative DNS server. The feature is described in RFC 2136. This facility is useful to register network clients into the DNS when they boot or become otherwise available on the network. As a booting client may be assigned a different IP address each time from a DHCP server, it is not possible to provide static DNS assignments for such clients.
From the time of its origin in 1983 the DNS has used the User Datagram Protocol (UDP) for transport over IP. Its limitations have motivated numerous protocol developments for reliability, security, privacy, and other criteria, in the following decades.
UDP reserves port number 53 for servers listening to queries. Such queries consist of a clear-text request sent in a single UDP packet from the client, responded to with a clear-text reply sent in a single UDP packet from the server. When the length of the answer exceeds 512 bytes and both client and server support Extension Mechanisms for DNS (EDNS), larger UDP packets may be used. Use of DNS over UDP is limited by, among other things, its lack of transport-layer encryption, authentication, reliable delivery, and message length. In 1989, RFC 1123 specified optional Transmission Control Protocol (TCP) transport for DNS queries, replies and, particularly, zone transfers. Via fragmentation of long replies, TCP allows longer responses, reliable delivery, and re-use of long-lived connections between clients and servers. For larger responses, the server refers the client to TCP transport.
DNS over TLS emerged as an IETF standard for encrypted DNS in 2016, utilizing Transport Layer Security (TLS) to protect the entire connection, rather than just the DNS payload. DoT servers listen on TCP port 853. RFC 7858 specifies that opportunistic encryption and authenticated encryption may be supported, but did not make either server or client authentication mandatory.
RFC 9250 by the Internet Engineering Task Force describes DNS over QUIC.
DNS over HTTPS was developed as a competing standard for DNS query transport in 2018, tunneling DNS query data over HTTPS, which transports HTTP over TLS. DoH was promoted as a more web-friendly alternative to DNS since, like DNSCrypt, it uses TCP port 443, and thus looks similar to web traffic, though they are easily differentiable in practice.
Oblivious DNS (ODNS) was invented and implemented by researchers at Princeton University and the University of Chicago as an extension to unencrypted DNS, before DoH was standardized and widely deployed. Apple and Cloudflare subsequently deployed the technology in the context of DoH, as Oblivious DoH (ODoH). ODoH combines ingress/egress separation (invented in ODNS) with DoH's HTTPS tunneling and TLS transport-layer encryption in a single protocol.
DNS may be run over virtual private networks (VPNs) and tunneling protocols. A use which has become common since 2019 to warrant its own frequently used acronym is DNS over Tor. The privacy gains of Oblivious DNS can be garnered through the use of the preexisting Tor network of ingress and egress nodes, paired with the transport-layer encryption provided by TLS.
The DNSCrypt protocol, which was developed in 2011 outside the IETF standards framework, introduced DNS encryption on the downstream side of recursive resolvers, wherein clients encrypt query payloads using servers' public keys, which are published in the DNS (rather than relying upon third-party certificate authorities) and which may in turn be protected by DNSSEC signatures. DNSCrypt uses either TCP or UDP port 443, the same port as HTTPS encrypted web traffic. This introduced not only privacy regarding the content of the query, but also a significant measure of firewall-traversal capability. In 2019, DNSCrypt was further extended to support an "anonymized" mode, similar to the proposed "Oblivious DNS," in which an ingress node receives a query which has been encrypted with the public key of a different server, and relays it to that server, which acts as an egress node, performing the recursive resolution. Privacy of user/query pairs is created, since the ingress node does not know the content of the query, while the egress nodes does not know the identity of the client. DNSCrypt was first implemented in production by OpenDNS in December 2011. There are several free and open source software implementations that additionally integrate ODoH. It is available for a variety of operating systems, including Unix, Apple iOS, Linux, Android, and MS Windows.
Originally, security concerns were not major design considerations for DNS software or any software for deployment on the early Internet, as the network was not open for participation by the general public. However, the expansion of the Internet into the commercial sector in the 1990s changed the requirements for security measures to protect data integrity and user authentication.
Several vulnerability issues were discovered and exploited by malicious users. One such issue is DNS cache poisoning, in which data is distributed to caching resolvers under the pretense of being an authoritative origin server, thereby polluting the data store with potentially false information and long expiration times (time-to-live). Subsequently, legitimate application requests may be redirected to network hosts operated with malicious intent.
DNS responses traditionally do not have a cryptographic signature, leading to many attack possibilities; the Domain Name System Security Extensions (DNSSEC) modify DNS to add support for cryptographically signed responses. DNSCurve has been proposed as an alternative to DNSSEC. Other extensions, such as TSIG, add support for cryptographic authentication between trusted peers and are commonly used to authorize zone transfer or dynamic update operations.
Some domain names may be used to achieve spoofing effects. For example, paypal.com and paypa1.com are different names, yet users may be unable to distinguish them in a graphical user interface depending on the user's chosen typeface. In many fonts the letter l and the numeral 1 look very similar or even identical. This problem, known as the IDN homograph attack, is acute in systems that support internationalized domain names, as many character codes in ISO 10646 may appear identical on typical computer screens. This vulnerability is occasionally exploited in phishing.
Techniques such as forward-confirmed reverse DNS can also be used to help validate DNS results.
DNS can also "leak" from otherwise secure or private connections, if attention is not paid to their configuration, and at times DNS has been used to bypass firewalls by malicious persons, and exfiltrate data, since it is often seen as innocuous.
Originally designed as a public, hierarchical, distributed and heavily cached database, DNS protocol has no confidentiality controls. User queries and nameserver responses are being sent unencrypted which enables network packet sniffing, DNS hijacking, DNS cache poisoning and man-in-the-middle attacks. This deficiency is commonly used by cybercriminals and network operators for marketing purposes, user authentication on captive portals and censorship.
User privacy is further exposed by proposals for increasing the level of client IP information in DNS queries (RFC 7871) for the benefit of Content Delivery Networks.
The main approaches that are in use to counter privacy issues with DNS:
Solutions preventing DNS inspection by local network operator are criticized for thwarting corporate network security policies and Internet censorship. They are also criticized from a privacy point of view, as giving away the DNS resolution to the hands of a small number of companies known for monetizing user traffic and for centralizing DNS name resolution, which is generally perceived as harmful for the Internet.
Google is the dominant provider of the platform in Android, the browser in Chrome, and the DNS resolver in the 8.8.8.8 service. Would this scenario be a case of a single corporate entity being in a position of overarching control of the entire namespace of the Internet? Netflix already fielded an app that used its own DNS resolution mechanism independent of the platform upon which the app was running. What if the Facebook app included DoH? What if Apple's iOS used a DoH-resolution mechanism to bypass local DNS resolution and steer all DNS queries from Apple's platforms to a set of Apple-operated name resolvers?
The right to use a domain name is delegated by domain name registrars which are accredited by the Internet Corporation for Assigned Names and Numbers (ICANN) or other organizations such as OpenNIC, that are charged with overseeing the name and number systems of the Internet. In addition to ICANN, each top-level domain (TLD) is maintained and serviced technically by an administrative organization, operating a registry. A registry is responsible for operating the database of names within its authoritative zone, although the term is most often used for TLDs. A registrant is a person or organization who asked for domain registration. The registry receives registration information from each domain name registrar, which is authorized (accredited) to assign names in the corresponding zone and publishes the information using the WHOIS protocol. As of 2015, usage of RDAP is being considered.
ICANN publishes the complete list of TLDs, TLD registries, and domain name registrars. Registrant information associated with domain names is maintained in an online database accessible with the WHOIS service. For most of the more than 290 country code top-level domains (ccTLDs), the domain registries maintain the WHOIS (Registrant, name servers, expiration dates, etc.) information. For instance, DENIC, Germany NIC, holds the DE domain data. From about 2001, most Generic top-level domain (gTLD) registries have adopted this so-called thick registry approach, i.e. keeping the WHOIS data in central registries instead of registrar databases.
For top-level domains on COM and NET, a thin registry model is used. The domain registry (e.g., GoDaddy, BigRock and PDR, VeriSign, etc., etc.) holds basic WHOIS data (i.e., registrar and name servers, etc.). Organizations, or registrants using ORG on the other hand, are on the Public Interest Registry exclusively.
Some domain name registries, often called network information centers (NIC), also function as registrars to end-users, in addition to providing access to the WHOIS datasets. The top-level domain registries, such as for the domains COM, NET, and ORG use a registry-registrar model consisting of many domain name registrars. In this method of management, the registry only manages the domain name database and the relationship with the registrars. The registrants (users of a domain name) are customers of the registrar, in some cases through additional subcontracting of resellers.
The Domain Name System is defined by Request for Comments (RFC) documents published by the Internet Engineering Task Force (Internet standards). The following is a list of RFCs that define the DNS protocol.
These RFCs are advisory in nature, but may provide useful information despite defining neither a standard or BCP. (RFC 1796)
These RFCs have an official status of Unknown, but due to their age are not clearly labeled as such. | [
{
"paragraph_id": 0,
"text": "The Domain Name System (DNS) is a hierarchical and distributed naming system for computers, services, and other resources in the Internet or other Internet Protocol (IP) networks. It associates various information with domain names (identification strings) assigned to each of the associated entities. Most prominently, it translates readily memorized domain names to the numerical IP addresses needed for locating and identifying computer services and devices with the underlying network protocols. The Domain Name System has been an essential component of the functionality of the Internet since 1985.",
"title": ""
},
{
"paragraph_id": 1,
"text": "The Domain Name System delegates the responsibility of assigning domain names and mapping those names to Internet resources by designating authoritative name servers for each domain. Network administrators may delegate authority over sub-domains of their allocated name space to other name servers. This mechanism provides distributed and fault-tolerant service and was designed to avoid a single large central database. In addition, the DNS specifies the technical functionality of the database service that is at its core. It defines the DNS protocol, a detailed specification of the data structures and data communication exchanges used in the DNS, as part of the Internet protocol suite.",
"title": ""
},
{
"paragraph_id": 2,
"text": "The Internet maintains two principal namespaces, the domain name hierarchy and the IP address spaces. The Domain Name System maintains the domain name hierarchy and provides translation services between it and the address spaces. Internet name servers and a communication protocol implement the Domain Name System. A DNS name server is a server that stores the DNS records for a domain; a DNS name server responds with answers to queries against its database.",
"title": ""
},
{
"paragraph_id": 3,
"text": "The most common types of records stored in the DNS database are for start of authority (SOA), IP addresses (A and AAAA), SMTP mail exchangers (MX), name servers (NS), pointers for reverse DNS lookups (PTR), and domain name aliases (CNAME). Although not intended to be a general purpose database, DNS has been expanded over time to store records for other types of data for either automatic lookups, such as DNSSEC records, or for human queries such as responsible person (RP) records. As a general purpose database, the DNS has also been used in combating unsolicited email (spam) by storing a real-time blackhole list (RBL). The DNS database is traditionally stored in a structured text file, the zone file, but other database systems are common.",
"title": ""
},
{
"paragraph_id": 4,
"text": "The Domain Name System originally used the User Datagram Protocol (UDP) as transport over IP. Reliability, security, and privacy concerns spawned the use of the Transmission Control Protocol (TCP) as well as numerous other protocol developments.",
"title": ""
},
{
"paragraph_id": 5,
"text": "An often-used analogy to explain the DNS is that it serves as the phone book for the Internet by translating human-friendly computer hostnames into IP addresses. For example, the hostname www.example.com within the domain name example.com translates to the addresses 93.184.216.34 (IPv4) and 2606:2800:220:1:248:1893:25c8:1946 (IPv6). The DNS can be quickly and transparently updated, allowing a service's location on the network to change without affecting the end users, who continue to use the same hostname. Users take advantage of this when they use meaningful Uniform Resource Locators (URLs) and e-mail addresses without having to know how the computer actually locates the services.",
"title": "Function"
},
{
"paragraph_id": 6,
"text": "An important and ubiquitous function of the DNS is its central role in distributed Internet services such as cloud services and content delivery networks. When a user accesses a distributed Internet service using a URL, the domain name of the URL is translated to the IP address of a server that is proximal to the user. The key functionality of the DNS exploited here is that different users can simultaneously receive different translations for the same domain name, a key point of divergence from a traditional phone-book view of the DNS. This process of using the DNS to assign proximal servers to users is key to providing faster and more reliable responses on the Internet and is widely used by most major Internet services.",
"title": "Function"
},
{
"paragraph_id": 7,
"text": "The DNS reflects the structure of administrative responsibility on the Internet. Each subdomain is a zone of administrative autonomy delegated to a manager. For zones operated by a registry, administrative information is often complemented by the registry's RDAP and WHOIS services. That data can be used to gain insight on, and track responsibility for, a given host on the Internet.",
"title": "Function"
},
{
"paragraph_id": 8,
"text": "Using a simpler, more memorable name in place of a host's numerical address dates back to the ARPANET era. The Stanford Research Institute (now SRI International) maintained a text file named HOSTS.TXT that mapped host names to the numerical addresses of computers on the ARPANET. Elizabeth Feinler developed and maintained the first ARPANET directory. Maintenance of numerical addresses, called the Assigned Numbers List, was handled by Jon Postel at the University of Southern California's Information Sciences Institute (ISI), whose team worked closely with SRI.",
"title": "History"
},
{
"paragraph_id": 9,
"text": "Addresses were assigned manually. Computers, including their hostnames and addresses, were added to the primary file by contacting the SRI Network Information Center (NIC), directed by Feinler, via telephone during business hours. Later, Feinler set up a WHOIS directory on a server in the NIC for retrieval of information about resources, contacts, and entities. She and her team developed the concept of domains. Feinler suggested that domains should be based on the location of the physical address of the computer. Computers at educational institutions would have the domain edu, for example. She and her team managed the Host Naming Registry from 1972 to 1989.",
"title": "History"
},
{
"paragraph_id": 10,
"text": "By the early 1980s, maintaining a single, centralized host table had become slow and unwieldy and the emerging network required an automated naming system to address technical and personnel issues. Postel directed the task of forging a compromise between five competing proposals of solutions to Paul Mockapetris. Mockapetris instead created the Domain Name System in 1983 while at the University of Southern California.",
"title": "History"
},
{
"paragraph_id": 11,
"text": "The Internet Engineering Task Force published the original specifications in RFC 882 and RFC 883 in November 1983. These were updated in RFC 973 in January 1986.",
"title": "History"
},
{
"paragraph_id": 12,
"text": "In 1984, four UC Berkeley students, Douglas Terry, Mark Painter, David Riggle, and Songnian Zhou, wrote the first Unix name server implementation for the Berkeley Internet Name Domain, commonly referred to as BIND. In 1985, Kevin Dunlap of DEC substantially revised the DNS implementation. Mike Karels, Phil Almquist, and Paul Vixie then took over BIND maintenance. Internet Systems Consortium was founded in 1994 by Rick Adams, Paul Vixie, and Carl Malamud, expressly to provide a home for BIND development and maintenance. BIND versions from 4.9.3 onward were developed and maintained by ISC, with support provided by ISC's sponsors. As co-architects/programmers, Bob Halley and Paul Vixie released the first production-ready version of BIND version 8 in May 1997. Since 2000, over 43 different core developers have worked on BIND.",
"title": "History"
},
{
"paragraph_id": 13,
"text": "In November 1987, RFC 1034 and RFC 1035 superseded the 1983 DNS specifications. Several additional Request for Comments have proposed extensions to the core DNS protocols.",
"title": "History"
},
{
"paragraph_id": 14,
"text": "The domain name space consists of a tree data structure. Each node or leaf in the tree has a label and zero or more resource records (RR), which hold information associated with the domain name. The domain name itself consists of the label, concatenated with the name of its parent node on the right, separated by a dot.",
"title": "Structure "
},
{
"paragraph_id": 15,
"text": "The tree sub-divides into zones beginning at the root zone. A DNS zone may consist of as many domains and sub domains as the zone manager chooses. DNS can also be partitioned according to class where the separate classes can be thought of as an array of parallel namespace trees.",
"title": "Structure "
},
{
"paragraph_id": 16,
"text": "Administrative responsibility for any zone may be divided by creating additional zones. Authority over the new zone is said to be delegated to a designated name server. The parent zone ceases to be authoritative for the new zone.",
"title": "Structure "
},
{
"paragraph_id": 17,
"text": "The definitive descriptions of the rules for forming domain names appear in RFC 1035, RFC 1123, RFC 2181, and RFC 5892. A domain name consists of one or more parts, technically called labels, that are conventionally concatenated, and delimited by dots, such as example.com.",
"title": "Structure "
},
{
"paragraph_id": 18,
"text": "The right-most label conveys the top-level domain; for example, the domain name www.example.com belongs to the top-level domain com.",
"title": "Structure "
},
{
"paragraph_id": 19,
"text": "The hierarchy of domains descends from right to left; each label to the left specifies a subdivision, or subdomain of the domain to the right. For example, the label example specifies a subdomain of the com domain, and www is a subdomain of example.com. This tree of subdivisions may have up to 127 levels.",
"title": "Structure "
},
{
"paragraph_id": 20,
"text": "A label may contain zero to 63 characters. The null label, of length zero, is reserved for the root zone. The full domain name may not exceed the length of 253 characters in its textual representation. In the internal binary representation of the DNS the maximum length requires 255 octets of storage, as it also stores the length of the name.",
"title": "Structure "
},
{
"paragraph_id": 21,
"text": "Although no technical limitation exists to prevent domain name labels using any character which is representable by an octet, hostnames use a preferred format and character set. The characters allowed in labels are a subset of the ASCII character set, consisting of characters a through z, A through Z, digits 0 through 9, and hyphen. This rule is known as the LDH rule (letters, digits, hyphen). Domain names are interpreted in case-independent manner. Labels may not start or end with a hyphen. An additional rule requires that top-level domain names should not be all-numeric.",
"title": "Structure "
},
{
"paragraph_id": 22,
"text": "The limited set of ASCII characters permitted in the DNS prevented the representation of names and words of many languages in their native alphabets or scripts. To make this possible, ICANN approved the Internationalizing Domain Names in Applications (IDNA) system, by which user applications, such as web browsers, map Unicode strings into the valid DNS character set using Punycode. In 2009 ICANN approved the installation of internationalized domain name country code top-level domains (ccTLDs). In addition, many registries of the existing top-level domain names (TLDs) have adopted the IDNA system, guided by RFC 5890, RFC 5891, RFC 5892, RFC 5893.",
"title": "Structure "
},
{
"paragraph_id": 23,
"text": "The Domain Name System is maintained by a distributed database system, which uses the client–server model. The nodes of this database are the name servers. Each domain has at least one authoritative DNS server that publishes information about that domain and the name servers of any domains subordinate to it. The top of the hierarchy is served by the root name servers, the servers to query when looking up (resolving) a TLD.",
"title": "Structure "
},
{
"paragraph_id": 24,
"text": "An authoritative name server is a name server that only gives answers to DNS queries from data that have been configured by an original source, for example, the domain administrator or by dynamic DNS methods, in contrast to answers obtained via a query to another name server that only maintains a cache of data.",
"title": "Structure "
},
{
"paragraph_id": 25,
"text": "An authoritative name server can either be a primary server or a secondary server. Historically the terms master/slave and primary/secondary were sometimes used interchangeably but the current practice is to use the latter form. A primary server is a server that stores the original copies of all zone records. A secondary server uses a special automatic updating mechanism in the DNS protocol in communication with its primary to maintain an identical copy of the primary records.",
"title": "Structure "
},
{
"paragraph_id": 26,
"text": "Every DNS zone must be assigned a set of authoritative name servers. This set of servers is stored in the parent domain zone with name server (NS) records.",
"title": "Structure "
},
{
"paragraph_id": 27,
"text": "An authoritative server indicates its status of supplying definitive answers, deemed authoritative, by setting a protocol flag, called the \"Authoritative Answer\" (AA) bit in its responses. This flag is usually reproduced prominently in the output of DNS administration query tools, such as dig, to indicate that the responding name server is an authority for the domain name in question.",
"title": "Structure "
},
{
"paragraph_id": 28,
"text": "When a name server is designated as the authoritative server for a domain name for which it does not have authoritative data, it presents a type of error called a \"lame delegation\" or \"lame response\".",
"title": "Structure "
},
{
"paragraph_id": 29,
"text": "Domain name resolvers determine the domain name servers responsible for the domain name in question by a sequence of queries starting with the right-most (top-level) domain label.",
"title": "Operation"
},
{
"paragraph_id": 30,
"text": "For proper operation of its domain name resolver, a network host is configured with an initial cache (hints) of the known addresses of the root name servers. The hints are updated periodically by an administrator by retrieving a dataset from a reliable source.",
"title": "Operation"
},
{
"paragraph_id": 31,
"text": "Assuming the resolver has no cached records to accelerate the process, the resolution process starts with a query to one of the root servers. In typical operation, the root servers do not answer directly, but respond with a referral to more authoritative servers, e.g., a query for \"www.wikipedia.org\" is referred to the org servers. The resolver now queries the servers referred to, and iteratively repeats this process until it receives an authoritative answer. The diagram illustrates this process for the host that is named by the fully qualified domain name \"www.wikipedia.org\".",
"title": "Operation"
},
{
"paragraph_id": 32,
"text": "This mechanism would place a large traffic burden on the root servers, if every resolution on the Internet required starting at the root. In practice caching is used in DNS servers to off-load the root servers, and as a result, root name servers actually are involved in only a relatively small fraction of all requests.",
"title": "Operation"
},
{
"paragraph_id": 33,
"text": "In theory, authoritative name servers are sufficient for the operation of the Internet. However, with only authoritative name servers operating, every DNS query must start with recursive queries at the root zone of the Domain Name System and each user system would have to implement resolver software capable of recursive operation.",
"title": "Operation"
},
{
"paragraph_id": 34,
"text": "To improve efficiency, reduce DNS traffic across the Internet, and increase performance in end-user applications, the Domain Name System supports DNS cache servers which store DNS query results for a period of time determined in the configuration (time-to-live) of the domain name record in question. Typically, such caching DNS servers also implement the recursive algorithm necessary to resolve a given name starting with the DNS root through to the authoritative name servers of the queried domain. With this function implemented in the name server, user applications gain efficiency in design and operation.",
"title": "Operation"
},
{
"paragraph_id": 35,
"text": "The combination of DNS caching and recursive functions in a name server is not mandatory; the functions can be implemented independently in servers for special purposes.",
"title": "Operation"
},
{
"paragraph_id": 36,
"text": "Internet service providers typically provide recursive and caching name servers for their customers. In addition, many home networking routers implement DNS caches and recursion to improve efficiency in the local network.",
"title": "Operation"
},
{
"paragraph_id": 37,
"text": "The client side of the DNS is called a DNS resolver. A resolver is responsible for initiating and sequencing the queries that ultimately lead to a full resolution (translation) of the resource sought, e.g., translation of a domain name into an IP address. DNS resolvers are classified by a variety of query methods, such as recursive, non-recursive, and iterative. A resolution process may use a combination of these methods.",
"title": "Operation"
},
{
"paragraph_id": 38,
"text": "In a non-recursive query, a DNS resolver queries a DNS server that provides a record either for which the server is authoritative, or it provides a partial result without querying other servers. In case of a caching DNS resolver, the non-recursive query of its local DNS cache delivers a result and reduces the load on upstream DNS servers by caching DNS resource records for a period of time after an initial response from upstream DNS servers.",
"title": "Operation"
},
{
"paragraph_id": 39,
"text": "In a recursive query, a DNS resolver queries a single DNS server, which may in turn query other DNS servers on behalf of the requester. For example, a simple stub resolver running on a home router typically makes a recursive query to the DNS server run by the user's ISP. A recursive query is one for which the DNS server answers the query completely by querying other name servers as needed. In typical operation, a client issues a recursive query to a caching recursive DNS server, which subsequently issues non-recursive queries to determine the answer and send a single answer back to the client. The resolver, or another DNS server acting recursively on behalf of the resolver, negotiates use of recursive service using bits in the query headers. DNS servers are not required to support recursive queries.",
"title": "Operation"
},
{
"paragraph_id": 40,
"text": "The iterative query procedure is a process in which a DNS resolver queries a chain of one or more DNS servers. Each server refers the client to the next server in the chain, until the current server can fully resolve the request. For example, a possible resolution of www.example.com would query a global root server, then a \"com\" server, and finally an \"example.com\" server.",
"title": "Operation"
},
{
"paragraph_id": 41,
"text": "Name servers in delegations are identified by name, rather than by IP address. This means that a resolving name server must issue another DNS request to find out the IP address of the server to which it has been referred. If the name given in the delegation is a subdomain of the domain for which the delegation is being provided, there is a circular dependency.",
"title": "Operation"
},
{
"paragraph_id": 42,
"text": "In this case, the name server providing the delegation must also provide one or more IP addresses for the authoritative name server mentioned in the delegation. This information is called glue. The delegating name server provides this glue in the form of records in the additional section of the DNS response, and provides the delegation in the authority section of the response. A glue record is a combination of the name server and IP address.",
"title": "Operation"
},
{
"paragraph_id": 43,
"text": "For example, if the authoritative name server for example.org is ns1.example.org, a computer trying to resolve www.example.org first resolves ns1.example.org. As ns1 is contained in example.org, this requires resolving example.org first, which presents a circular dependency. To break the dependency, the name server for the top level domain org includes glue along with the delegation for example.org. The glue records are address records that provide IP addresses for ns1.example.org. The resolver uses one or more of these IP addresses to query one of the domain's authoritative servers, which allows it to complete the DNS query.",
"title": "Operation"
},
{
"paragraph_id": 44,
"text": "A standard practice in implementing name resolution in applications is to reduce the load on the Domain Name System servers by caching results locally, or in intermediate resolver hosts. Results obtained from a DNS request are always associated with the time to live (TTL), an expiration time after which the results must be discarded or refreshed. The TTL is set by the administrator of the authoritative DNS server. The period of validity may vary from a few seconds to days or even weeks.",
"title": "Operation"
},
{
"paragraph_id": 45,
"text": "As a result of this distributed caching architecture, changes to DNS records do not propagate throughout the network immediately, but require all caches to expire and to be refreshed after the TTL. RFC 1912 conveys basic rules for determining appropriate TTL values.",
"title": "Operation"
},
{
"paragraph_id": 46,
"text": "Some resolvers may override TTL values, as the protocol supports caching for up to sixty-eight years or no caching at all. Negative caching, i.e. the caching of the fact of non-existence of a record, is determined by name servers authoritative for a zone which must include the Start of Authority (SOA) record when reporting no data of the requested type exists. The value of the minimum field of the SOA record and the TTL of the SOA itself is used to establish the TTL for the negative answer.",
"title": "Operation"
},
{
"paragraph_id": 47,
"text": "A reverse DNS lookup is a query of the DNS for domain names when the IP address is known. Multiple domain names may be associated with an IP address. The DNS stores IP addresses in the form of domain names as specially formatted names in pointer (PTR) records within the infrastructure top-level domain arpa. For IPv4, the domain is in-addr.arpa. For IPv6, the reverse lookup domain is ip6.arpa. The IP address is represented as a name in reverse-ordered octet representation for IPv4, and reverse-ordered nibble representation for IPv6.",
"title": "Operation"
},
{
"paragraph_id": 48,
"text": "When performing a reverse lookup, the DNS client converts the address into these formats before querying the name for a PTR record following the delegation chain as for any DNS query. For example, assuming the IPv4 address 208.80.152.2 is assigned to Wikimedia, it is represented as a DNS name in reverse order: 2.152.80.208.in-addr.arpa. When the DNS resolver gets a pointer (PTR) request, it begins by querying the root servers, which point to the servers of American Registry for Internet Numbers (ARIN) for the 208.in-addr.arpa zone. ARIN's servers delegate 152.80.208.in-addr.arpa to Wikimedia to which the resolver sends another query for 2.152.80.208.in-addr.arpa, which results in an authoritative response.",
"title": "Operation"
},
{
"paragraph_id": 49,
"text": "Users generally do not communicate directly with a DNS resolver. Instead DNS resolution takes place transparently in applications such as web browsers, e-mail clients, and other Internet applications. When an application makes a request that requires a domain name lookup, such programs send a resolution request to the DNS resolver in the local operating system, which in turn handles the communications required.",
"title": "Operation"
},
{
"paragraph_id": 50,
"text": "The DNS resolver will almost invariably have a cache (see above) containing recent lookups. If the cache can provide the answer to the request, the resolver will return the value in the cache to the program that made the request. If the cache does not contain the answer, the resolver will send the request to one or more designated DNS servers. In the case of most home users, the Internet service provider to which the machine connects will usually supply this DNS server: such a user will either have configured that server's address manually or allowed DHCP to set it; however, where systems administrators have configured systems to use their own DNS servers, their DNS resolvers point to separately maintained name servers of the organization. In any event, the name server thus queried will follow the process outlined above, until it either successfully finds a result or does not. It then returns its results to the DNS resolver; assuming it has found a result, the resolver duly caches that result for future use, and hands the result back to the software which initiated the request.",
"title": "Operation"
},
{
"paragraph_id": 51,
"text": "Some large ISPs have configured their DNS servers to violate rules, such as by disobeying TTLs, or by indicating that a domain name does not exist just because one of its name servers does not respond.",
"title": "Operation"
},
{
"paragraph_id": 52,
"text": "Some applications such as web browsers maintain an internal DNS cache to avoid repeated lookups via the network. This practice can add extra difficulty when debugging DNS issues as it obscures the history of such data. These caches typically use very short caching times on the order of one minute.",
"title": "Operation"
},
{
"paragraph_id": 53,
"text": "Internet Explorer represents a notable exception: versions up to IE 3.x cache DNS records for 24 hours by default. Internet Explorer 4.x and later versions (up to IE 8) decrease the default timeout value to half an hour, which may be changed by modifying the default configuration.",
"title": "Operation"
},
{
"paragraph_id": 54,
"text": "When Google Chrome detects issues with the DNS server it displays a specific error message.",
"title": "Operation"
},
{
"paragraph_id": 55,
"text": "The Domain Name System includes several other functions and features.",
"title": "Operation"
},
{
"paragraph_id": 56,
"text": "Hostnames and IP addresses are not required to match in a one-to-one relationship. Multiple hostnames may correspond to a single IP address, which is useful in virtual hosting, in which many web sites are served from a single host. Alternatively, a single hostname may resolve to many IP addresses to facilitate fault tolerance and load distribution to multiple server instances across an enterprise or the global Internet.",
"title": "Operation"
},
{
"paragraph_id": 57,
"text": "DNS serves other purposes in addition to translating names to IP addresses. For instance, mail transfer agents use DNS to find the best mail server to deliver e-mail: An MX record provides a mapping between a domain and a mail exchanger; this can provide an additional layer of fault tolerance and load distribution.",
"title": "Operation"
},
{
"paragraph_id": 58,
"text": "The DNS is used for efficient storage and distribution of IP addresses of blacklisted email hosts. A common method is to place the IP address of the subject host into the sub-domain of a higher level domain name, and to resolve that name to a record that indicates a positive or a negative indication.",
"title": "Operation"
},
{
"paragraph_id": 59,
"text": "For example:",
"title": "Operation"
},
{
"paragraph_id": 60,
"text": "E-mail servers can query blacklist.example to find out if a specific host connecting to them is in the blacklist. Many of such blacklists, either subscription-based or free of cost, are available for use by email administrators and anti-spam software.",
"title": "Operation"
},
{
"paragraph_id": 61,
"text": "To provide resilience in the event of computer or network failure, multiple DNS servers are usually provided for coverage of each domain. At the top level of global DNS, thirteen groups of root name servers exist, with additional \"copies\" of them distributed worldwide via anycast addressing.",
"title": "Operation"
},
{
"paragraph_id": 62,
"text": "Dynamic DNS (DDNS) updates a DNS server with a client IP address on-the-fly, for example, when moving between ISPs or mobile hot spots, or when the IP address changes administratively.",
"title": "Operation"
},
{
"paragraph_id": 63,
"text": "The DNS protocol uses two types of DNS messages, queries and responses; both have the same format. Each message consists of a header and four sections: question, answer, authority, and an additional space. A header field (flags) controls the content of these four sections.",
"title": "DNS message format"
},
{
"paragraph_id": 64,
"text": "The header section consists of the following fields: Identification, Flags, Number of questions, Number of answers, Number of authority resource records (RRs), and Number of additional RRs. Each field is 16 bits long, and appears in the order given. The identification field is used to match responses with queries. The flag field consists of sub-fields as follows:",
"title": "DNS message format"
},
{
"paragraph_id": 65,
"text": "After the flag, the header ends with four 16-bit integers which contain the number of records in each of the sections that follow, in the same order.",
"title": "DNS message format"
},
{
"paragraph_id": 66,
"text": "The question section has a simpler format than the resource record format used in the other sections. Each question record (there is usually just one in the section) contains the following fields:",
"title": "DNS message format"
},
{
"paragraph_id": 67,
"text": "The domain name is broken into discrete labels which are concatenated; each label is prefixed by the length of that label.",
"title": "DNS message format"
},
{
"paragraph_id": 68,
"text": "The Domain Name System specifies a database of information elements for network resources. The types of information elements are categorized and organized with a list of DNS record types, the resource records (RRs). Each record has a type (name and number), an expiration time (time to live), a class, and type-specific data. Resource records of the same type are described as a resource record set (RRset), having no special ordering. DNS resolvers return the entire set upon query, but servers may implement round-robin ordering to achieve load balancing. In contrast, the Domain Name System Security Extensions (DNSSEC) work on the complete set of resource record in canonical order.",
"title": "Resource records"
},
{
"paragraph_id": 69,
"text": "When sent over an Internet Protocol network, all records use the common format specified in RFC 1035:",
"title": "Resource records"
},
{
"paragraph_id": 70,
"text": "NAME is the fully qualified domain name of the node in the tree . On the wire, the name may be shortened using label compression where ends of domain names mentioned earlier in the packet can be substituted for the end of the current domain name.",
"title": "Resource records"
},
{
"paragraph_id": 71,
"text": "TYPE is the record type. It indicates the format of the data and it gives a hint of its intended use. For example, the A record is used to translate from a domain name to an IPv4 address, the NS record lists which name servers can answer lookups on a DNS zone, and the MX record specifies the mail server used to handle mail for a domain specified in an e-mail address.",
"title": "Resource records"
},
{
"paragraph_id": 72,
"text": "RDATA is data of type-specific relevance, such as the IP address for address records, or the priority and hostname for MX records. Well known record types may use label compression in the RDATA field, but \"unknown\" record types must not (RFC 3597).",
"title": "Resource records"
},
{
"paragraph_id": 73,
"text": "The CLASS of a record is set to IN (for Internet) for common DNS records involving Internet hostnames, servers, or IP addresses. In addition, the classes Chaos (CH) and Hesiod (HS) exist. Each class is an independent name space with potentially different delegations of DNS zones.",
"title": "Resource records"
},
{
"paragraph_id": 74,
"text": "In addition to resource records defined in a zone file, the domain name system also defines several request types that are used only in communication with other DNS nodes (on the wire), such as when performing zone transfers (AXFR/IXFR) or for EDNS (OPT).",
"title": "Resource records"
},
{
"paragraph_id": 75,
"text": "The domain name system supports wildcard DNS records which specify names that start with the asterisk label, '*', e.g., *.example. DNS records belonging to wildcard domain names specify rules for generating resource records within a single DNS zone by substituting whole labels with matching components of the query name, including any specified descendants. For example, in the following configuration, the DNS zone x.example specifies that all subdomains, including subdomains of subdomains, of x.example use the mail exchanger (MX) a.x.example. The A record for a.x.example is needed to specify the mail exchanger IP address. As this has the result of excluding this domain name and its subdomains from the wildcard matches, an additional MX record for the subdomain a.x.example, as well as a wildcarded MX record for all of its subdomains, must also be defined in the DNS zone.",
"title": "Resource records"
},
{
"paragraph_id": 76,
"text": "The role of wildcard records was refined in RFC 4592, because the original definition in RFC 1034 was incomplete and resulted in misinterpretations by implementers.",
"title": "Resource records"
},
{
"paragraph_id": 77,
"text": "The original DNS protocol had limited provisions for extension with new features. In 1999, Paul Vixie published in RFC 2671 (superseded by RFC 6891) an extension mechanism, called Extension Mechanisms for DNS (EDNS) that introduced optional protocol elements without increasing overhead when not in use. This was accomplished through the OPT pseudo-resource record that only exists in wire transmissions of the protocol, but not in any zone files. Initial extensions were also suggested (EDNS0), such as increasing the DNS message size in UDP datagrams.",
"title": "Protocol extensions"
},
{
"paragraph_id": 78,
"text": "Dynamic DNS updates use the UPDATE DNS opcode to add or remove resource records dynamically from a zone database maintained on an authoritative DNS server. The feature is described in RFC 2136. This facility is useful to register network clients into the DNS when they boot or become otherwise available on the network. As a booting client may be assigned a different IP address each time from a DHCP server, it is not possible to provide static DNS assignments for such clients.",
"title": "Dynamic zone updates"
},
{
"paragraph_id": 79,
"text": "From the time of its origin in 1983 the DNS has used the User Datagram Protocol (UDP) for transport over IP. Its limitations have motivated numerous protocol developments for reliability, security, privacy, and other criteria, in the following decades.",
"title": "Transport protocols"
},
{
"paragraph_id": 80,
"text": "UDP reserves port number 53 for servers listening to queries. Such queries consist of a clear-text request sent in a single UDP packet from the client, responded to with a clear-text reply sent in a single UDP packet from the server. When the length of the answer exceeds 512 bytes and both client and server support Extension Mechanisms for DNS (EDNS), larger UDP packets may be used. Use of DNS over UDP is limited by, among other things, its lack of transport-layer encryption, authentication, reliable delivery, and message length. In 1989, RFC 1123 specified optional Transmission Control Protocol (TCP) transport for DNS queries, replies and, particularly, zone transfers. Via fragmentation of long replies, TCP allows longer responses, reliable delivery, and re-use of long-lived connections between clients and servers. For larger responses, the server refers the client to TCP transport.",
"title": "Transport protocols"
},
{
"paragraph_id": 81,
"text": "DNS over TLS emerged as an IETF standard for encrypted DNS in 2016, utilizing Transport Layer Security (TLS) to protect the entire connection, rather than just the DNS payload. DoT servers listen on TCP port 853. RFC 7858 specifies that opportunistic encryption and authenticated encryption may be supported, but did not make either server or client authentication mandatory.",
"title": "Transport protocols"
},
{
"paragraph_id": 82,
"text": "RFC 9250 by the Internet Engineering Task Force describes DNS over QUIC.",
"title": "Transport protocols"
},
{
"paragraph_id": 83,
"text": "DNS over HTTPS was developed as a competing standard for DNS query transport in 2018, tunneling DNS query data over HTTPS, which transports HTTP over TLS. DoH was promoted as a more web-friendly alternative to DNS since, like DNSCrypt, it uses TCP port 443, and thus looks similar to web traffic, though they are easily differentiable in practice.",
"title": "Transport protocols"
},
{
"paragraph_id": 84,
"text": "Oblivious DNS (ODNS) was invented and implemented by researchers at Princeton University and the University of Chicago as an extension to unencrypted DNS, before DoH was standardized and widely deployed. Apple and Cloudflare subsequently deployed the technology in the context of DoH, as Oblivious DoH (ODoH). ODoH combines ingress/egress separation (invented in ODNS) with DoH's HTTPS tunneling and TLS transport-layer encryption in a single protocol.",
"title": "Transport protocols"
},
{
"paragraph_id": 85,
"text": "DNS may be run over virtual private networks (VPNs) and tunneling protocols. A use which has become common since 2019 to warrant its own frequently used acronym is DNS over Tor. The privacy gains of Oblivious DNS can be garnered through the use of the preexisting Tor network of ingress and egress nodes, paired with the transport-layer encryption provided by TLS.",
"title": "Transport protocols"
},
{
"paragraph_id": 86,
"text": "The DNSCrypt protocol, which was developed in 2011 outside the IETF standards framework, introduced DNS encryption on the downstream side of recursive resolvers, wherein clients encrypt query payloads using servers' public keys, which are published in the DNS (rather than relying upon third-party certificate authorities) and which may in turn be protected by DNSSEC signatures. DNSCrypt uses either TCP or UDP port 443, the same port as HTTPS encrypted web traffic. This introduced not only privacy regarding the content of the query, but also a significant measure of firewall-traversal capability. In 2019, DNSCrypt was further extended to support an \"anonymized\" mode, similar to the proposed \"Oblivious DNS,\" in which an ingress node receives a query which has been encrypted with the public key of a different server, and relays it to that server, which acts as an egress node, performing the recursive resolution. Privacy of user/query pairs is created, since the ingress node does not know the content of the query, while the egress nodes does not know the identity of the client. DNSCrypt was first implemented in production by OpenDNS in December 2011. There are several free and open source software implementations that additionally integrate ODoH. It is available for a variety of operating systems, including Unix, Apple iOS, Linux, Android, and MS Windows.",
"title": "Transport protocols"
},
{
"paragraph_id": 87,
"text": "Originally, security concerns were not major design considerations for DNS software or any software for deployment on the early Internet, as the network was not open for participation by the general public. However, the expansion of the Internet into the commercial sector in the 1990s changed the requirements for security measures to protect data integrity and user authentication.",
"title": "Security issues"
},
{
"paragraph_id": 88,
"text": "Several vulnerability issues were discovered and exploited by malicious users. One such issue is DNS cache poisoning, in which data is distributed to caching resolvers under the pretense of being an authoritative origin server, thereby polluting the data store with potentially false information and long expiration times (time-to-live). Subsequently, legitimate application requests may be redirected to network hosts operated with malicious intent.",
"title": "Security issues"
},
{
"paragraph_id": 89,
"text": "DNS responses traditionally do not have a cryptographic signature, leading to many attack possibilities; the Domain Name System Security Extensions (DNSSEC) modify DNS to add support for cryptographically signed responses. DNSCurve has been proposed as an alternative to DNSSEC. Other extensions, such as TSIG, add support for cryptographic authentication between trusted peers and are commonly used to authorize zone transfer or dynamic update operations.",
"title": "Security issues"
},
{
"paragraph_id": 90,
"text": "Some domain names may be used to achieve spoofing effects. For example, paypal.com and paypa1.com are different names, yet users may be unable to distinguish them in a graphical user interface depending on the user's chosen typeface. In many fonts the letter l and the numeral 1 look very similar or even identical. This problem, known as the IDN homograph attack, is acute in systems that support internationalized domain names, as many character codes in ISO 10646 may appear identical on typical computer screens. This vulnerability is occasionally exploited in phishing.",
"title": "Security issues"
},
{
"paragraph_id": 91,
"text": "Techniques such as forward-confirmed reverse DNS can also be used to help validate DNS results.",
"title": "Security issues"
},
{
"paragraph_id": 92,
"text": "DNS can also \"leak\" from otherwise secure or private connections, if attention is not paid to their configuration, and at times DNS has been used to bypass firewalls by malicious persons, and exfiltrate data, since it is often seen as innocuous.",
"title": "Security issues"
},
{
"paragraph_id": 93,
"text": "Originally designed as a public, hierarchical, distributed and heavily cached database, DNS protocol has no confidentiality controls. User queries and nameserver responses are being sent unencrypted which enables network packet sniffing, DNS hijacking, DNS cache poisoning and man-in-the-middle attacks. This deficiency is commonly used by cybercriminals and network operators for marketing purposes, user authentication on captive portals and censorship.",
"title": "Privacy and tracking issues"
},
{
"paragraph_id": 94,
"text": "User privacy is further exposed by proposals for increasing the level of client IP information in DNS queries (RFC 7871) for the benefit of Content Delivery Networks.",
"title": "Privacy and tracking issues"
},
{
"paragraph_id": 95,
"text": "The main approaches that are in use to counter privacy issues with DNS:",
"title": "Privacy and tracking issues"
},
{
"paragraph_id": 96,
"text": "Solutions preventing DNS inspection by local network operator are criticized for thwarting corporate network security policies and Internet censorship. They are also criticized from a privacy point of view, as giving away the DNS resolution to the hands of a small number of companies known for monetizing user traffic and for centralizing DNS name resolution, which is generally perceived as harmful for the Internet.",
"title": "Privacy and tracking issues"
},
{
"paragraph_id": 97,
"text": "Google is the dominant provider of the platform in Android, the browser in Chrome, and the DNS resolver in the 8.8.8.8 service. Would this scenario be a case of a single corporate entity being in a position of overarching control of the entire namespace of the Internet? Netflix already fielded an app that used its own DNS resolution mechanism independent of the platform upon which the app was running. What if the Facebook app included DoH? What if Apple's iOS used a DoH-resolution mechanism to bypass local DNS resolution and steer all DNS queries from Apple's platforms to a set of Apple-operated name resolvers?",
"title": "Privacy and tracking issues"
},
{
"paragraph_id": 98,
"text": "The right to use a domain name is delegated by domain name registrars which are accredited by the Internet Corporation for Assigned Names and Numbers (ICANN) or other organizations such as OpenNIC, that are charged with overseeing the name and number systems of the Internet. In addition to ICANN, each top-level domain (TLD) is maintained and serviced technically by an administrative organization, operating a registry. A registry is responsible for operating the database of names within its authoritative zone, although the term is most often used for TLDs. A registrant is a person or organization who asked for domain registration. The registry receives registration information from each domain name registrar, which is authorized (accredited) to assign names in the corresponding zone and publishes the information using the WHOIS protocol. As of 2015, usage of RDAP is being considered.",
"title": "Domain name registration"
},
{
"paragraph_id": 99,
"text": "ICANN publishes the complete list of TLDs, TLD registries, and domain name registrars. Registrant information associated with domain names is maintained in an online database accessible with the WHOIS service. For most of the more than 290 country code top-level domains (ccTLDs), the domain registries maintain the WHOIS (Registrant, name servers, expiration dates, etc.) information. For instance, DENIC, Germany NIC, holds the DE domain data. From about 2001, most Generic top-level domain (gTLD) registries have adopted this so-called thick registry approach, i.e. keeping the WHOIS data in central registries instead of registrar databases.",
"title": "Domain name registration"
},
{
"paragraph_id": 100,
"text": "For top-level domains on COM and NET, a thin registry model is used. The domain registry (e.g., GoDaddy, BigRock and PDR, VeriSign, etc., etc.) holds basic WHOIS data (i.e., registrar and name servers, etc.). Organizations, or registrants using ORG on the other hand, are on the Public Interest Registry exclusively.",
"title": "Domain name registration"
},
{
"paragraph_id": 101,
"text": "Some domain name registries, often called network information centers (NIC), also function as registrars to end-users, in addition to providing access to the WHOIS datasets. The top-level domain registries, such as for the domains COM, NET, and ORG use a registry-registrar model consisting of many domain name registrars. In this method of management, the registry only manages the domain name database and the relationship with the registrars. The registrants (users of a domain name) are customers of the registrar, in some cases through additional subcontracting of resellers.",
"title": "Domain name registration"
},
{
"paragraph_id": 102,
"text": "The Domain Name System is defined by Request for Comments (RFC) documents published by the Internet Engineering Task Force (Internet standards). The following is a list of RFCs that define the DNS protocol.",
"title": "RFC documents"
},
{
"paragraph_id": 103,
"text": "These RFCs are advisory in nature, but may provide useful information despite defining neither a standard or BCP. (RFC 1796)",
"title": "RFC documents"
},
{
"paragraph_id": 104,
"text": "These RFCs have an official status of Unknown, but due to their age are not clearly labeled as such.",
"title": "RFC documents"
}
] | The Domain Name System (DNS) is a hierarchical and distributed naming system for computers, services, and other resources in the Internet or other Internet Protocol (IP) networks. It associates various information with domain names assigned to each of the associated entities. Most prominently, it translates readily memorized domain names to the numerical IP addresses needed for locating and identifying computer services and devices with the underlying network protocols. The Domain Name System has been an essential component of the functionality of the Internet since 1985. The Domain Name System delegates the responsibility of assigning domain names and mapping those names to Internet resources by designating authoritative name servers for each domain. Network administrators may delegate authority over sub-domains of their allocated name space to other name servers. This mechanism provides distributed and fault-tolerant service and was designed to avoid a single large central database. In addition, the DNS specifies the technical functionality of the database service that is at its core. It defines the DNS protocol, a detailed specification of the data structures and data communication exchanges used in the DNS, as part of the Internet protocol suite. The Internet maintains two principal namespaces, the domain name hierarchy and the IP address spaces. The Domain Name System maintains the domain name hierarchy and provides translation services between it and the address spaces. Internet name servers and a communication protocol implement the Domain Name System. A DNS name server is a server that stores the DNS records for a domain; a DNS name server responds with answers to queries against its database. The most common types of records stored in the DNS database are for start of authority (SOA), IP addresses, SMTP mail exchangers (MX), name servers (NS), pointers for reverse DNS lookups (PTR), and domain name aliases (CNAME). Although not intended to be a general purpose database, DNS has been expanded over time to store records for other types of data for either automatic lookups, such as DNSSEC records, or for human queries such as responsible person (RP) records. As a general purpose database, the DNS has also been used in combating unsolicited email (spam) by storing a real-time blackhole list (RBL). The DNS database is traditionally stored in a structured text file, the zone file, but other database systems are common. The Domain Name System originally used the User Datagram Protocol (UDP) as transport over IP. Reliability, security, and privacy concerns spawned the use of the Transmission Control Protocol (TCP) as well as numerous other protocol developments. | 2001-08-20T10:20:39Z | 2023-12-24T06:42:25Z | [
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8,340 | David Letterman | David Michael Letterman (born April 12, 1947) is an American television host, comedian, writer and producer. He hosted late-night television talk shows for 33 years, beginning with the February 1, 1982, debut of Late Night with David Letterman on NBC and ending with the May 20, 2015, broadcast of Late Show with David Letterman on CBS. In total, Letterman hosted 6,080 episodes of Late Night and Late Show, surpassing his friend and mentor Johnny Carson as the longest-serving late-night talk show host in American television history.
He is also a television and film producer. His company, Worldwide Pants, produced his shows as well as The Late Late Show and several primetime comedies, the most successful of which was the CBS sitcom Everybody Loves Raymond. Several late-night hosts have cited Letterman's influence, including Conan O'Brien (his successor on Late Night), Stephen Colbert (his successor on The Late Show), Jimmy Fallon, Jimmy Kimmel, Jon Stewart, and Seth Meyers. Since 2018 he has hosted the Netflix series My Next Guest Needs No Introduction with David Letterman.
Letterman was born in Indianapolis, Indiana, in 1947, and has two sisters, one older and one younger. His father, Harry Joseph Letterman (April 15, 1915 – February 13, 1973), was a florist. His mother, Dorothy Marie Letterman Mengering (née Hofert; July 18, 1921 – April 11, 2017), a church secretary for the Second Presbyterian Church of Indianapolis, was an occasional figure on Letterman's show, usually at holidays and birthdays.
Letterman grew up on the north side of Indianapolis, in the Broad Ripple area, about 12 miles (19 km) from the Indianapolis Motor Speedway. He enjoyed collecting model cars, including racers. In 2000, he told an interviewer for Esquire that, while growing up, he admired his father's ability to tell jokes and be the life of the party. Harry Joseph Letterman survived a heart attack at the age of 36 when David was a young boy. The fear of losing his father was constantly with Letterman as he grew up. The elder Letterman died of a second heart attack in 1973 at the age of 57.
Letterman attended his hometown's Broad Ripple High School and worked as a stock boy at the local Atlas Supermarket. According to the Ball State Daily News, he originally wanted to attend Indiana University, but his grades were not good enough, so he instead attended Ball State University in Muncie, Indiana. He is a member of the Sigma Chi fraternity, and graduated in 1969 from what was then the Department of Radio and Television. A self-described average student, Letterman later endowed a scholarship for what he called "C students" at Ball State. Though he registered for the draft and passed his physical after graduating from college, he was not drafted for service in Vietnam because he received a draft lottery number of 346 (out of 366).
Letterman began his broadcasting career as an announcer and newscaster at the college's student-run radio station—WBST—a 10-watt campus station that is now part of Indiana Public Radio. He was fired for treating classical music with irreverence. He then became involved with the founding of another campus station—WAGO-AM 570 (now WCRD, 91.3).
He credits Paul Dixon, host of the Paul Dixon Show, a Cincinnati-based talk show also shown in Indianapolis while he was growing up, for inspiring his choice of career:
I was just out of college [in 1969], and I really didn't know what I wanted to do. And then all of a sudden I saw him doing it [on TV]. And I thought: That's really what I want to do!
Soon after graduating from Ball State in 1969, Letterman began his career as a radio talk show host on WNTS (AM) and on Indianapolis television station WLWI (which changed its call sign to WTHR in 1976) as an anchor and weatherman. He received some attention for his unpredictable on-air behavior, which included congratulating a tropical storm for being upgraded to a hurricane and predicting hailstones "the size of canned hams." He also occasionally reported the weather and the day's very high and low temps for fictitious cities ("Eight inches of snow in Bingree and surrounding areas"), on another occasion saying that the state border between Indiana and Ohio had been erased when a satellite map accidentally omitted it, attributing it to dirty political dealings. ("The higher-ups have removed the border between Indiana and Ohio, making it one giant state. Personally, I'm against it. I don't know what to do about it.") He also starred in a local kiddie show, made wisecracks as host of a late-night TV show called "Freeze-Dried Movies" (he once acted out a scene from Godzilla using plastic dinosaurs), and hosted a talk show that aired early on Saturday mornings called Clover Power, in which he interviewed 4-H members about their projects.
In 1971, Letterman appeared as a pit road reporter for ABC Sports' tape-delayed coverage of the Indianapolis 500, which was his first nationally telecast appearance (WLWI was the local ABC affiliate at the time). He was initially introduced as Chris Economaki, but this was corrected at the end of the interview (Jim McKay announced his name as Dave Letterman). Letterman interviewed Mario Andretti, who had just crashed out of the race.
In 1975, encouraged by his then-wife Michelle and several of his Sigma Chi fraternity brothers, Letterman moved to Los Angeles, California, with the hope of becoming a comedy writer. He and Michelle packed their belongings in his pickup truck and headed west. As of 2012, he still owned the truck. In Los Angeles, he began performing comedy at The Comedy Store. Jimmie Walker saw him on stage; with an endorsement from George Miller, Letterman joined a group of comedians whom Walker hired to write jokes for his stand-up act, a group that at various times also included Jay Leno, Paul Mooney, Robert Schimmel, Richard Jeni, Louie Anderson, Elayne Boosler, Byron Allen, Jack Handey, and Steve Oedekerk.
By the summer of 1977, Letterman was a writer and regular on the six-week summer series The Starland Vocal Band Show, broadcast on CBS. He hosted a 1977 pilot for a game show called The Riddlers (which was never picked up), and co-starred in the Barry Levinson-produced comedy special Peeping Times, which aired in January 1978. Later that year, Letterman was a cast member on Mary Tyler Moore's variety show, Mary. He made a guest appearance on Mork & Mindy (as a parody of EST leader Werner Erhard) and appearances on game shows such as The $20,000 Pyramid, The Gong Show, Hollywood Squares, Password Plus, and Liar's Club, as well as the Canadian cooking show Celebrity Cooks (November 1977), talk shows such as 90 Minutes Live (February 24 and April 14, 1978), and The Mike Douglas Show (April 3, 1979 and February 7, 1980). He was also screen tested for the lead role in the 1980 film Airplane!, a role that eventually went to Robert Hays.
Letterman's brand of dry, sarcastic humor caught the attention of scouts for The Tonight Show Starring Johnny Carson, and he was soon a regular guest on the show. He became a favorite of Carson and was a regular guest host for the show beginning in 1978. Letterman credits Carson as the person who influenced his career the most.
On June 23, 1980, Letterman was given his own morning comedy show on NBC, The David Letterman Show. It was originally 90 minutes long but was shortened to 60 minutes in August 1980. The show was a critical success, winning two Emmy Awards, but was a ratings disappointment and was canceled, the last show airing October 24, 1980.
NBC kept Letterman on its payroll to try him in a different time slot. Late Night with David Letterman debuted February 1, 1982; the first guest was Bill Murray. Murray went on to become one of Letterman's most recurrent guests, guesting on his later CBS show's celebration of his 30th anniversary in late-night television, which aired January 31, 2012, and on the final CBS show, which aired May 20, 2015. The show ran Monday through Thursday nights at 12:30 a.m. Eastern Time, immediately following The Tonight Show Starring Johnny Carson (a Friday night broadcast was added in June 1987). It was seen as edgy and unpredictable, and soon developed a cult following (particularly among college students). Letterman's reputation as an acerbic interviewer was borne out in verbal sparring matches with Cher (who even called him an "asshole" on the show), Shirley MacLaine, Charles Grodin, and Madonna. The show also featured comedy segments and running characters, in a style heavily influenced by the 1950s and 1960s programs of Steve Allen.
The show often featured quirky, genre-mocking regular features, including "Stupid Pet Tricks" (which had its origins on Letterman's morning show), Stupid Human Tricks, dropping various objects off the roof of a five-story building, demonstrations of unorthodox clothing (such as suits made of Alka-Seltzer, Velcro and suet), a recurring Top 10 list, the Monkey-Cam (and the Audience Cam), a facetious letter-answering segment, several "Film[s] by My Dog Bob" in which a camera was mounted on Letterman's own dog (often with comic results) and Small Town News, all of which moved with Letterman to CBS.
Other episodes included Letterman using a bullhorn to interrupt a live interview on The Today Show on August 19, 1985, announcing that he was the NBC News president Lawrence K. Grossman and that he was not wearing any pants; walking across the hall to Studio 6B, at the time the news studio for WNBC-TV, and interrupting Al Roker's weather segments during Live at Five; and staging "elevator races", complete with commentary by NBC Sports' Bob Costas. In one appearance, in 1982, Andy Kaufman (who was wearing a neck brace) appeared with professional wrestler Jerry Lawler, who slapped and knocked the comedian to the ground (Lawler and Kaufman's friend Bob Zmuda later revealed that the incident was staged).
In 1992, Johnny Carson retired, and many fans, and Carson himself, believed that Letterman would become the new host of The Tonight Show. When NBC instead gave the job to Jay Leno, Letterman departed NBC to host his own late-night show on CBS, opposite The Tonight Show at 11:30 p.m., called the Late Show with David Letterman. The new show debuted on August 30, 1993, and was taped at the historic Ed Sullivan Theater, where Ed Sullivan broadcast his eponymous variety series from 1948 to 1971. For Letterman's arrival, CBS spent $8 million in renovations. CBS also signed Letterman to a three-year, $14 million/year contract, doubling his Late Night salary.
But while the expectation was that Letterman would retain his unique style and sense of humor with the move, Late Show was not an exact replica of his old NBC program. The monologue was lengthened. Paul Shaffer and the World's Most Dangerous Band followed Letterman to CBS, but they added a brass section and were rebranded the CBS Orchestra (at Shaffer's request); a small band had been mandated by Carson while Letterman occupied the 12:30 slot. Additionally, because of intellectual property disagreements, Letterman was unable to import many of his Late Night segments verbatim, but he sidestepped this problem by simply renaming them (the "Top Ten List" became the "Late Show Top Ten", "Viewer Mail" became the "CBS Mailbag", etc.). Time magazine wrote, "Letterman's innovation ... gained power from its rigorous formalism"; as his biographer Jason Zinoman puts it, he was "a fascinatingly disgruntled eccentric trapped inside a more traditional talk show."
The Late Show's main competitor was NBC's The Tonight Show, which Jay Leno hosted for 22 years from 1992 to 2014, except from June 1, 2009, to January 22, 2010, when Conan O'Brien hosted. In 1993 and 1994, the Late Show consistently gained higher ratings than The Tonight Show. But in 1995, ratings dipped and Leno's show consistently beat Letterman's in the ratings from the time that Hugh Grant came on Leno's show after Grant's arrest for soliciting a prostitute.
Leno typically attracted about five million nightly viewers between 1999 and 2009. The Late Show lost nearly half its audience during its competition with Leno, attracting 7.1 million viewers nightly in its 1993–94 season and about 3.8 million per night as of Leno's departure in 2009. In the final months of his first stint as host of The Tonight Show, Leno beat Letterman in the ratings by a 1.3 million-viewer margin (5.2 million to 3.9 million), and Nightline and the Late Show were virtually tied. Once O'Brien took over Tonight, Letterman closed the gap in the ratings. O'Brien initially drove the median age of Tonight Show viewers from 55 to 45, with most older viewers opting to watch the Late Show instead. After Leno returned to The Tonight Show, Leno regained his lead.
Letterman's shows have garnered both critical and industry praise, receiving 67 Emmy Award nominations, winning 12 times in his first 20 years in late night television. From 1993 to 2009, Letterman ranked higher than Leno in the annual Harris Poll of Nation's Favorite TV Personality 12 times. For example, in 2003 and 2004 Letterman ranked second in that poll, behind only Oprah Winfrey, a year that Leno was ranked fifth. Leno was higher than Letterman on that poll three times during the same period, in 1998, 2007, and 2008.
On March 27, 1995, Letterman hosted the 67th Academy Awards ceremony. Critics blasted what they deemed his poor performance, noting that his irreverent style undermined the traditional importance and glamor of the event. In a joke about their unusual names (inspired by a celebrated comic essay in The New Yorker, "Yma Dream" by Thomas Meehan), he started off by introducing Uma Thurman to Oprah Winfrey, and then both of them to Keanu Reeves: "Oprah...Uma. Uma...Oprah," "Have you kids met Keanu?" This and many of his other jokes fell flat. Although Letterman attracted the highest ratings to the annual telecast since 1983, many felt that the bad publicity he generated caused a decline in the Late Show's ratings.
Letterman recycled the apparent debacle into a long-running gag. On his first show after the Oscars, he joked, "Looking back, I had no idea that thing was being televised." He lampooned his stint two years later, during Billy Crystal's opening Oscar skit, which also parodied the plane-crashing scenes from that year's chief nominated film, The English Patient.
For years afterward, Letterman recounted his hosting the Oscars, although the Academy of Motion Picture Arts and Sciences continued to hold Letterman in high regard and invited him to host the Oscars again. On September 7, 2010, he made an appearance on the premiere of the 14th season of The View, and confirmed that he had been considered for hosting again.
On January 14, 2000, a routine check-up revealed that an artery in Letterman's heart was severely obstructed. He was rushed to emergency surgery for a quintuple bypass at New York Presbyterian Hospital. During the initial weeks of his recovery, reruns of the Late Show were shown and introduced by friends of Letterman including Norm Macdonald, Drew Barrymore, Ray Romano, Robin Williams, Bonnie Hunt, Megan Mullally, Bill Murray, Regis Philbin, Charles Grodin, Nathan Lane, Julia Roberts, Bruce Willis, Jerry Seinfeld, Martin Short, Steven Seagal, Hillary Clinton, Danny DeVito, Steve Martin, and Sarah Jessica Parker.
Subsequently, while still recovering from surgery, Letterman revived the late-night talk show tradition of "guest hosts" that had virtually disappeared on network television during the 1990s, allowing Bill Cosby, Kathie Lee Gifford, Dana Carvey, Janeane Garofalo, and others to host new episodes of the Late Show. Upon his return to the show on February 21, 2000, Letterman brought all but one of the doctors and nurses on stage who had participated in his surgery and recovery (with extra teasing of a nurse who had given him bed baths—"This woman gave me a bath!"), including Dr. O. Wayne Isom and physician Louis Aronne, who frequently appeared on the show.
For a number of episodes, Letterman continued to crack jokes about his bypass, including saying, "Bypass surgery: it's when doctors surgically create new blood flow to your heart. A bypass is what happened to me when I didn't get The Tonight Show! It's a whole different thing." In a later running gag, he lobbied Indiana to rename the freeway circling Indianapolis (I-465) "The David Letterman Bypass". He also featured a montage of faux news coverage of his bypass surgery, which included a clip of Letterman's heart for sale on the Home Shopping Network. Letterman became friends with his doctors and nurses. In 2008, a Rolling Stone interview stated
he hosted a doctor and nurse who'd helped perform the emergency quintuple-bypass heart surgery that saved his life in 2000. 'These are people who were complete strangers when they opened my chest,' he says. 'And now, eight years later, they're among my best friends.'
Additionally, Letterman invited the band Foo Fighters to play "Everlong", introducing them as "my favorite band, playing my favorite song." During Letterman's last show, on which Foo Fighters appeared, Letterman said that Foo Fighters had been in the middle of a South American tour which they canceled to come play on his comeback episode.
Letterman again handed over the reins of the show to several guest hosts (including Bill Cosby, Brad Garrett, Whoopi Goldberg, Elvis Costello, John McEnroe, Vince Vaughn, Will Ferrell, Bonnie Hunt, Luke Wilson, and bandleader Paul Shaffer) in February 2003, when he was diagnosed with a severe case of shingles. Later that year, Letterman made regular use of guest hosts—including Tom Arnold and Kelsey Grammer—for new shows broadcast on Fridays. In March 2007, Adam Sandler, who had been scheduled to be the lead guest, served as a guest host while Letterman was ill with a stomach virus.
In March 2002, as Letterman's contract with CBS neared expiration, ABC offered him the time slot for long-running news program Nightline with Ted Koppel. Letterman was interested, as he believed he could never match Leno's ratings at CBS due to Letterman's complaint of weaker lead-ins from the network's late local news programs, but was reluctant to replace Koppel. He addressed his decision to re-sign on the air, stating that he was content at CBS and that he had great respect for Koppel.
On December 4, 2006, CBS revealed that Letterman signed a new contract to host Late Show with David Letterman through the fall of 2010. "I'm thrilled to be continuing on at CBS," said Letterman. "At my age you really don't want to have to learn a new commute." Letterman further joked about the subject by pulling up his right pants leg, revealing a tattoo, presumably temporary, of the ABC logo.
"Thirteen years ago, David Letterman put CBS late night on the map and in the process became one of the defining icons of our network," said Leslie Moonves, president and CEO of CBS Corporation. "His presence on our air is an ongoing source of pride, and the creativity and imagination that the Late Show puts forth every night is an ongoing display of the highest quality entertainment. We are truly honored that one of the most revered and talented entertainers of our time will continue to call CBS 'home.'"
According to a 2007 article in Forbes magazine, Letterman earned $40 million a year. A 2009 article in The New York Times, however, said his salary was estimated at $32 million. In June 2009, Letterman's Worldwide Pants and CBS reached an agreement to continue the Late Show until at least August 2012. The previous contract had been set to expire in 2010, and the two-year extension was shorter than the typical three-year contract period negotiated in the past. Worldwide Pants agreed to lower its fee for the show, though it had remained a "solid moneymaker for CBS" under the previous contract.
On the February 3, 2011 edition of the Late Show, during an interview with Howard Stern, Letterman said he would continue to do his talk show for "maybe two years, I think." In April 2012, CBS announced it had extended its contract with Letterman through 2014. His contract was subsequently extended to 2015.
During the taping of his show on April 3, 2014, Letterman announced that he had informed CBS president Leslie Moonves that he would retire from hosting Late Show by May 20, 2015. Later in his retirement Letterman occasionally stated, in jest, that he had been fired. It was announced soon after that comedian and political satirist Stephen Colbert would succeed Letterman. Letterman's last episode aired on May 20, 2015, and opened with a presidential sendoff featuring four of the five living American presidents, George H. W. Bush, Bill Clinton, George W. Bush, and Barack Obama, each mimicking the late president Gerald Ford's statement "Our long national nightmare is over." It also featured cameos from The Simpsons and Wheel of Fortune (the latter with a puzzle saying "Good riddance to David Letterman"), a Top Ten List of "things I wish I could have said to David Letterman" performed by regular guests including Alec Baldwin, Barbara Walters, Steve Martin, Jerry Seinfeld, Jim Carrey, Chris Rock, Julia Louis-Dreyfus, Peyton Manning, Tina Fey, and Bill Murray, and closed with a montage of scenes from both his CBS and NBC series set to a live performance of "Everlong" by Foo Fighters.
The final episode of Late Show with David Letterman was watched by 13.76 million viewers in the United States with an audience share of 9.3/24, earning the show its highest ratings since following the 1994 Winter Olympics on February 25, 1994, and the show's highest demo numbers (4.1 in adults 25–54 and 3.1 in adults 18–49) since Oprah Winfrey's first Late Show appearance following the ending of her feud with Letterman on December 1, 2005. Bill Murray, who had been his first guest on Late Night, was his final guest on Late Show. In a rarity for a late-night show, it was also the highest-rated program on network television that night, beating out all prime-time shows. In total, Letterman hosted 6,080 episodes of Late Night and Late Show, surpassing friend and mentor Johnny Carson as the longest-serving late-night talk show host in U.S. television history.
In the months following the end of Late Show, Letterman was seen occasionally at sports events such as the Indianapolis 500, during which he submitted to an interview with a local publication. He made a surprise appearance on stage in San Antonio, Texas when he was invited up for an extended segment during Steve Martin's and Martin Short's A Very Stupid Conversation show, saying "I retired, and...I have no regrets," Letterman told the crowd after walking on stage. "I was happy. I'll make actual friends. I was complacent. I was satisfied. I was content, and then a couple of days ago Donald Trump said he was running for president. I have made the biggest mistake of my life, ladies and gentlemen" and then delivering a Top Ten List roasting Trump's presidential campaign followed by an onstage conversation with Martin and Short. Cellphone recordings of the appearance were posted on YouTube by audience members and widely reported in the media.
In 2016, Letterman joined the climate change documentary show Years of Living Dangerously as one of its celebrity correspondents. In season two's premiere episode, Letterman traveled to India to investigate the country's efforts to expand its inadequate energy grid, power its booming economy, and bring electricity to 300 million citizens for the first time. He also interviewed Indian Prime Minister Narendra Modi and traveled to rural villages where power is a scarce luxury and explored the United States' role in India's energy future.
On April 7, 2017, Letterman gave the induction speech for the band Pearl Jam into the Rock & Roll Hall Of Fame at a ceremony held at the Barclays Center in Brooklyn, New York City. Also in 2017, Letterman and Alec Baldwin co-hosted The Essentials on Turner Classic Movies. Letterman and Baldwin introduced seven films for the series.
In 2018, Letterman began hosting a six-episode monthly series of hour-long programs on Netflix consisting of long-form interviews and field segments. The show, My Next Guest Needs No Introduction with David Letterman, premiered January 12, 2018 with Barack Obama as its first guest. The second season premiered on May 31, 2019. Season 3 premiered on October 21, 2020, and includes Kim Kardashian West, Robert Downey Jr., Dave Chappelle and Lizzo as guests. Season 4 premiered on May 20, 2022, with Billie Eilish as the first guest. In October 2022, Letterman traveled to Kyiv, Ukraine, to film a special standalone episode of My Next Guest Needs No Introduction with David Letterman, interviewing Ukrainian president Volodymyr Zelenskyy.
In spite of Johnny Carson's clear intention to pass his title to Letterman, NBC selected Jay Leno to host The Tonight Show after Carson's departure. Letterman maintained a close relationship with Carson through his break with NBC. Three years after he left for CBS, HBO produced a made-for-television movie called The Late Shift, based on a book by The New York Times reporter Bill Carter, chronicling the battle between Letterman and Leno for the Tonight Show hosting spot.
Carson later made a few cameo appearances as a guest on Letterman's show. Carson's final television appearance was on May 13, 1994, on a Late Show episode taped in Los Angeles, when he made a surprise appearance during a Top 10 list segment. In early 2005, it was revealed that Carson occasionally sent jokes to Letterman, who used them in his monologue; according to CBS senior vice president Peter Lassally (a onetime producer for both men), Carson got "a big kick out of it." Letterman would do a characteristic Carson golf swing after delivering one of his jokes. In a tribute to Carson, all the opening monologue jokes during the first show after Carson's death were by Carson.
Lassally also claimed that Carson had always believed Letterman, not Leno, to be his "rightful successor". During the early years of the Late Show's run, Letterman occasionally used some of Carson's trademark bits, including "Carnac the Magnificent" (with Paul Shaffer as Carnac), "Stump the Band", and the "Week in Review".
Oprah Winfrey appeared on Letterman's show when he was hosting NBC's Late Night on May 2, 1989. After that appearance, the two had a 16-year feud that arose, as Winfrey explained to Letterman after it had been resolved, as a result of the acerbic tone of their 1989 interview, of which she said that it "felt so uncomfortable to me that I didn't want to have that experience again". The feud apparently ended on December 2, 2005, when Winfrey appeared on CBS's Late Show with David Letterman in an event Letterman jokingly called "the Super Bowl of Love".
Winfrey and Letterman also appeared together in a Late Show promo aired during CBS's coverage of Super Bowl XLI in February 2007, with the two sitting next to each other on a couch watching the game. Since the game was played between the Indianapolis Colts and Chicago Bears, the Indianapolis-born Letterman wore a Peyton Manning jersey, while Winfrey, whose show was taped in Chicago, wore a Brian Urlacher jersey. On September 10, 2007, Letterman made his first appearance on The Oprah Winfrey Show at Madison Square Garden in New York City.
Three years later, during CBS's coverage of Super Bowl XLIV between the Colts and the New Orleans Saints, the two appeared again in a Late Show promo, this time with Winfrey sitting on a couch between Letterman and Leno. Letterman wore the retired No. 70 jersey of Art Donovan, a member of the Colts' Hall of Fame and a regular Letterman guest. The appearance was Letterman's idea: Leno flew to New York City on an NBC corporate jet, sneaking into the Ed Sullivan Theater during the Late Show's February 4 taping wearing a disguise and meeting Winfrey and Letterman at a living room set created in the theater's balcony, where they taped their promo.
Winfrey interviewed Letterman in January 2013 on Oprah's Next Chapter. They discussed their feud and Winfrey revealed that she had had a "terrible experience" while appearing on Letterman's show years earlier. Letterman could not recall the incident but apologized.
Late Show went off air for eight weeks in 2007 during November and December because of the Writers Guild of America strike. Letterman's production company, Worldwide Pants, was the first company to make an individual agreement with the WGA, allowing his show to come back on the air on January 2, 2008. In his first episode back, he surprised the audience with a newly grown beard, which signified solidarity with the strike. His beard was shaved off during the show on January 7, 2008.
On June 8 and 9, 2009, Letterman told two sexually themed jokes about a daughter (never named) of Sarah Palin on his TV show. These included a statutory rape joke about Palin's then 14-year-old daughter, Willow, and MLB player Alex Rodriguez. Palin was in New York City at the time with Willow, and none of her other children were at the game.
In a statement posted on the Internet, Palin said, "I doubt [Letterman would] ever dare make such comments about anyone else's daughter" and that "laughter incited by sexually perverted comments made by a 62-year-old male celebrity aimed at a 14-year-old girl is disgusting." On his June 10 show, Letterman responded to the controversy, saying the jokes were meant to be about Palin's 18-year-old daughter, Bristol, whose pregnancy as an unmarried teenager had caused some controversy during the United States presidential election of 2008. "These are not jokes made about [Palin's] 14-year-old daughter ... I would never, never make jokes about raping or having sex of any description with a 14-year-old girl."
His remarks did not end public criticism. The National Organization for Women (NOW) released a statement supporting Palin, noting that Letterman had made "[only] something of an apology." When the controversy failed to subside, Letterman addressed the issue again on his June 15 show, faulting himself for the error and apologizing "especially to the two daughters involved, Bristol and Willow, and also to the governor and her family and everybody else who was outraged by the joke." Rodriguez demanded an apology for implying that he was a child molester. Letterman never specifically apologized to Rodriguez.
On August 17, 2011, it was reported that an Islamist militant had posted a death threat against Letterman on a website frequented by Al-Qaeda supporters, calling on American Muslims to kill him for making a joke about the death of Ilyas Kashmiri, an Al-Qaeda leader who was killed in a June 2011 drone strike in Pakistan. In his August 22 show, Letterman joked about the threat, saying "State Department authorities are looking into this. They're not taking this lightly. They're looking into it. They're questioning, they're interrogating, there's an electronic trail—but everybody knows it's Leno."
Letterman appeared in the pilot episode of the short-lived 1986 series Coach Toast, and appears with a bag over his head as a guest on Bonnie Hunt's 1990s sitcom The Building. He appeared in The Simpsons as himself in a couch gag when the Simpsons find themselves (and the couch) in Late Night with David Letterman. He had a cameo in the feature film Cabin Boy, with Chris Elliott, who worked as a writer for Letterman. In this and other appearances, Letterman is listed in the credits as "Earl Hofert", the name of Letterman's maternal grandfather. He also appeared as himself in the Howard Stern biographical film Private Parts and the 1999 Andy Kaufman biopic Man on the Moon, in a few episodes of Garry Shandling's 1990s TV series The Larry Sanders Show, and in "The Abstinence", a 1996 episode of the sitcom Seinfeld.
Letterman provided vocals for the Warren Zevon song "Hit Somebody" from My Ride's Here, and provided the voice for Butt-head's father in the 1996 animated film Beavis and Butt-Head Do America, again credited as Earl Hofert.
Letterman was the focus of The Avengers on "Late Night with David Letterman", issue 239 (January 1984) of the Marvel comic book series The Avengers, in which the title characters (specifically Hawkeye, Wonder Man, Black Widow, Beast, and Black Panther) are guests on Late Night. A parody of Letterman named David Endochrine is gassed to death along with his bandleader, Paul, and their audience in Frank Miller's The Dark Knight Returns. In SWAT Kats: The Radical Squadron, Letterman was parodied as "David Litterbin". Letterman appears in issues 13–14 and 18 of Harvey Pekar's autobiographical comic book American Splendor. Those issues show Pekar's accounts of appearances on Late Night.
In 2010, a documentary directed by Joke Fincioen and Biagio Messina, Dying to do Letterman, was released, featuring Steve Mazan, a standup comic, who has cancer and wants to appear on Letterman's show. The film won best documentary and jury awards at the Cinequest Film Festival. Mazan published a book of the same name (full title Dying to Do Letterman: Turning Someday into Today) about his own saga.
Letterman appeared as a guest on CNN's Piers Morgan Tonight on May 29, 2012, when he was interviewed by Regis Philbin, the guest host and Letterman's longtime friend. Philbin again interviewed Letterman (and Shaffer) while guest-hosting CBS's The Late Late Show (between the tenures of Craig Ferguson and James Corden) on January 27, 2015. In June 2013, Letterman appeared in the second episode of season two of Comedians in Cars Getting Coffee. On November 5, 2013, he and Bruce McCall published a fiction satire book, This Land Was Made for You and Me (But Mostly Me), ISBN 0-399-16368-9.
In Week 13 of the 2021 NFL season, Letterman joined Peyton and Eli Manning on their Manningcast feed of the Monday Night Football game between the New England Patriots and Buffalo Bills. Letterman mocked Bill Belichick after he was caught on camera wiping his nose with his shirt and was in the middle of recalling being with Roger Goodell when Goodell was booed at the unveiling of Peyton Manning's statue in Indianapolis when ESPN suddenly cut to commercials.
On February 1, 2022, Letterman was the guest on Late Night with Seth Meyers, marking the 40th anniversary of the franchise's debut.
On November 20, 2023, Letterman returned to the Ed Sullivan theater on The Late Show with Stephen Colbert.
Letterman started his production company, Worldwide Pants Incorporated, which produced his show and several others, in 1991. The company also produces feature films and documentaries and founded its own record label, Clear Entertainment. Worldwide Pants received significant attention in December 2007 after it was announced that it had independently negotiated its own contract with the Writers Guild of America, East, thus allowing Letterman, Craig Ferguson, and their writers to return to work, while the union continued its strike against production companies, networks, and studios with whom it had not yet reached agreements.
Letterman, Bobby Rahal, and Mike Lanigan co-own Rahal Letterman Lanigan Racing, an auto racing team competing in the WeatherTech SportsCar Championship and NTT IndyCar series. The team has twice won the Indianapolis 500: in 2004 with driver Buddy Rice, and in 2020 with Takuma Sato.
The Letterman Foundation for Courtesy and Grooming is a private foundation through which Letterman has donated millions of dollars to charities and other nonprofit organizations in Indiana and Montana, celebrity-affiliated organizations such as Paul Newman's Hole in the Wall Gang Camp, Ball State University, the American Cancer Society, the Salvation Army, and Médecins Sans Frontières.
Letterman's biggest influence and mentor was Johnny Carson. Other comedians who influenced Letterman were Paul Dixon, Steve Allen, Jonathan Winters, Garry Moore, Jack Paar, Don Rickles, and David Brenner. Although Ernie Kovacs has also been mentioned as an influence, Letterman has denied this.
Comedians influenced by Letterman include Conan O'Brien, Jon Stewart, Stephen Colbert, Ray Romano, Jimmy Kimmel, Jay Leno, Arsenio Hall, Larry Wilmore, Seth Meyers, Norm Macdonald, Jimmy Fallon, John Oliver, and James Corden.
Letterman has tinnitus, a symptom of hearing loss. On the Late Show in 1996, he talked about his experience with tinnitus during an interview with William Shatner, who has severe tinnitus caused by an on-set explosion. Letterman has said that he was initially unable to pinpoint the noise inside his head and that he hears a constant ringing in his ears.
Letterman no longer drinks alcohol. On more than one occasion, he said that he had once been a "horrible alcoholic" and had begun drinking around the age of 13 and continued until 1981 when he was 34. He has said that in 1981, "I was drunk 80% of the time ... I loved it. I was one of those guys, I looked around, and everyone else had stopped drinking and I couldn't understand why." When he was shown drinking what appears to be alcohol on Late Night or the Late Show, it was actually apple juice.
In 2015, Letterman said of his anxiety: "For years and years and years—30, 40 years—I was anxious and hypochondriacal and an alcoholic, and many, many other things that made me different from other people." He became calmer through a combination of Transcendental Meditation and low doses of medication. Letterman is a Presbyterian, a religious tradition he was originally brought up in by his mother, though he once said he was motivated by "Lutheran, Midwestern guilt".
In August 2021, Letterman was hospitalized in Providence, Rhode Island, after hitting his head on the sidewalk and falling unconscious. He favorably recalled the care he received at Rhode Island Hospital in a video released by the hospital's owner.
On July 2, 1968, Letterman married his college sweetheart, Michelle Cook, in Muncie, Indiana; they divorced by October 1977. He also had a long-term cohabiting relationship with the former head writer and producer on Late Night, Merrill Markoe, from 1978 to 1988. Markoe created several Late Night staples, such as "Stupid Pet/Human Tricks". Time magazine wrote that theirs was the defining relationship of Letterman's career, with Markoe also acting as his writing partner. She "put the surrealism in Letterman's comedy."
Letterman and Regina Lasko started dating in February 1986, while he was still living with Markoe. Lasko gave birth to their son, Harry Joseph Letterman, on November 3, 2003. Harry is named after Letterman's father. In 2005, police discovered a plot to kidnap Letterman's son and demand a $5 million ransom. Kelly Frank, a house painter who had worked for Letterman, was charged in the conspiracy.
Letterman and Lasko wed on March 19, 2009, in a quiet courthouse civil ceremony in Choteau, Montana, where he had purchased a ranch in 1999. Letterman announced the marriage during the taping of his show of March 23, shortly after congratulating Bruce Willis on his marriage the week before. Letterman told the audience he nearly missed the ceremony because his truck became stuck in mud two miles from their house. The family resides in North Salem, New York, on a 108-acre (44-hectare) estate.
On October 1, 2009, Letterman announced on his show that he had been the victim of a blackmail attempt by a person threatening to reveal his sexual relationships with several of his female employees—a fact Letterman immediately thereafter confirmed. He said that someone had left a package in his car with material he said he would write into a screenplay and a book if Letterman did not pay him $2 million. Letterman said that he contacted the Manhattan District Attorney's office and partook in a sting operation that involved the handover of a fake check to the extortionist.
Joe Halderman, a producer of the CBS news magazine television series 48 Hours, was arrested around noon (EST) on October 1, 2009, after trying to deposit the check. He was indicted by a Manhattan grand jury following testimony from Letterman and pleaded not guilty to a charge of attempted grand larceny on October 2, 2009. Halderman pleaded guilty in March 2010 and was sentenced to six months in prison, followed by probation and community service.
A central figure in the case and one of the women with whom Letterman had had a sexual relationship was his longtime personal assistant Stephanie Birkitt, who often appeared on the show. She had also worked for 48 Hours. Until a month before the revelations, she had shared a residence with Halderman, who allegedly had copied her personal diary and used it, along with private emails, in the blackmail package.
In the days following the initial announcement of the affairs and the arrest, several prominent women, including Kathie Lee Gifford, co-host of NBC's Today Show, and NBC news anchor Ann Curry, questioned whether Letterman's affairs with subordinates created an unfair working environment. A spokesman for Worldwide Pants said that the company's sexual harassment policy did not prohibit sexual relationships between managers and employees. According to business news reporter Eve Tahmincioglu, "CBS suppliers are supposed to follow the company's business conduct policies" and the CBS 2008 Business Conduct Statement states that "If a consenting romantic or sexual relationship between a supervisor and a direct or indirect subordinate should develop, CBS requires the supervisor to disclose this information to his or her Company's Human Resources Department".
On October 3, 2009, TMZ reported that a former CBS employee, Holly Hester, had had a yearlong secret affair with Letterman in the early 1990s while she was his intern and a student at New York University. On October 5, 2009, Letterman devoted a segment of his show to a public apology to his wife and staff. Three days later, Worldwide Pants announced that Birkitt had been placed on a "paid leave of absence" from the Late Show.
Beginning in May 1988, Letterman was stalked by Margaret Mary Ray, a woman with schizophrenia. She stole his Porsche, camped out on his tennis court, and repeatedly broke into his house. Her exploits drew national attention, with Letterman occasionally joking about her on his show, though he never named her. After she died by suicide at age 46 in October 1998, Letterman told The New York Times that he had great compassion for her. A spokesperson for Letterman said: "This is a sad ending to a confused life."
In 2005, a woman was able to obtain a restraining order from a New Mexico judge, prohibiting Letterman from contacting her. She claimed he had sent her coded messages via his television program, causing her bankruptcy and emotional distress. Law professor Eugene Volokh called the case "patently frivolous".
Letterman is a car enthusiast and owns an extensive collection. In 2012, it was reported that the collection consisted of ten Ferraris, eight Porsches, four Austin-Healeys, two Honda motorcycles, a Chevy pickup, and one car each from automakers Mercedes-Benz, Jaguar, MG, Volvo, and Pontiac.
In his 2013 appearance on Comedians in Cars Getting Coffee, part of Jerry Seinfeld's conversation with Letterman was filmed in Letterman's 1995 Volvo 960 station wagon, which is powered by a 380-horsepower racing engine. Paul Newman had the car built for Letterman.
Letterman shares a close relationship with the rock band Foo Fighters since its appearance on his first show upon his return from heart surgery. The band appeared many times on the Late Show, including a week-long stint in October 2014. While introducing the band's performance of "Miracle" on the show of October 17, 2014, Letterman told the story of how a souvenir video of himself and his four-year-old son learning to ski used the song as background music, unbeknownst to Letterman until he saw it. He stated: "This is the second song of theirs that will always have great, great meaning for me for the rest of my life". This was the first time the band had heard this story. Worldwide Pants co-produced Dave Grohl's Sonic Highways TV series. "Letterman was the first person to get behind this project," Grohl said.
David Letterman Communication and Media Building
In 1996, Letterman was ranked 45th on TV Guide's 50 Greatest TV Stars of All Time. In 2002, The Late Show with David Letterman was ranked seventh on TV Guide's 50 Greatest TV Shows of All Time.
On September 7, 2007, Letterman visited his alma mater, Ball State University in Muncie, Indiana, for the dedication of a communications facility named in his honor for his dedication to the university. The $21 million, 75,000-square-foot (7,000 m) David Letterman Communication and Media Building opened for the 2007 fall semester. Thousands of Ball State students, faculty, and local residents welcomed Letterman back to Indiana. Letterman's emotional speech touched on his struggles as a college student and his late father, and also included the "top ten good things about having your name on a building", finishing with "if reasonable people can put my name on a $21 million building, anything is possible." Over many years Letterman "has provided substantial assistance to [Ball State's] Department of Telecommunications, including an annual scholarship that bears his name."
At the same time, Indiana Governor Mitch Daniels gave Letterman a Sagamore of the Wabash award, which recognizes distinguished service to the state of Indiana.
Awards and nominations
In his capacities as a performer, producer, or as part of a writing team, Letterman is among the most nominated people in the history of the Emmy Awards, with 52 nominations, winning two Daytime Emmys and ten Primetime Emmys since 1981. He won four American Comedy Awards and in 2011 became the first recipient of the Johnny Carson Award for Comedic Excellence at The Comedy Awards.
Letterman was a recipient of the 2012 Kennedy Center Honors, where he was called "one of the most influential personalities in the history of television, entertaining an entire generation of late-night viewers with his unconventional wit and charm." On May 16, 2017, Letterman was named the next recipient of the Mark Twain Prize for American Humor, the award granted annually by the John F. Kennedy Center for the Performing Arts. He received the prize in a ceremony on October 22, 2017. | [
{
"paragraph_id": 0,
"text": "David Michael Letterman (born April 12, 1947) is an American television host, comedian, writer and producer. He hosted late-night television talk shows for 33 years, beginning with the February 1, 1982, debut of Late Night with David Letterman on NBC and ending with the May 20, 2015, broadcast of Late Show with David Letterman on CBS. In total, Letterman hosted 6,080 episodes of Late Night and Late Show, surpassing his friend and mentor Johnny Carson as the longest-serving late-night talk show host in American television history.",
"title": ""
},
{
"paragraph_id": 1,
"text": "He is also a television and film producer. His company, Worldwide Pants, produced his shows as well as The Late Late Show and several primetime comedies, the most successful of which was the CBS sitcom Everybody Loves Raymond. Several late-night hosts have cited Letterman's influence, including Conan O'Brien (his successor on Late Night), Stephen Colbert (his successor on The Late Show), Jimmy Fallon, Jimmy Kimmel, Jon Stewart, and Seth Meyers. Since 2018 he has hosted the Netflix series My Next Guest Needs No Introduction with David Letterman.",
"title": ""
},
{
"paragraph_id": 2,
"text": "Letterman was born in Indianapolis, Indiana, in 1947, and has two sisters, one older and one younger. His father, Harry Joseph Letterman (April 15, 1915 – February 13, 1973), was a florist. His mother, Dorothy Marie Letterman Mengering (née Hofert; July 18, 1921 – April 11, 2017), a church secretary for the Second Presbyterian Church of Indianapolis, was an occasional figure on Letterman's show, usually at holidays and birthdays.",
"title": "Early life and career"
},
{
"paragraph_id": 3,
"text": "Letterman grew up on the north side of Indianapolis, in the Broad Ripple area, about 12 miles (19 km) from the Indianapolis Motor Speedway. He enjoyed collecting model cars, including racers. In 2000, he told an interviewer for Esquire that, while growing up, he admired his father's ability to tell jokes and be the life of the party. Harry Joseph Letterman survived a heart attack at the age of 36 when David was a young boy. The fear of losing his father was constantly with Letterman as he grew up. The elder Letterman died of a second heart attack in 1973 at the age of 57.",
"title": "Early life and career"
},
{
"paragraph_id": 4,
"text": "Letterman attended his hometown's Broad Ripple High School and worked as a stock boy at the local Atlas Supermarket. According to the Ball State Daily News, he originally wanted to attend Indiana University, but his grades were not good enough, so he instead attended Ball State University in Muncie, Indiana. He is a member of the Sigma Chi fraternity, and graduated in 1969 from what was then the Department of Radio and Television. A self-described average student, Letterman later endowed a scholarship for what he called \"C students\" at Ball State. Though he registered for the draft and passed his physical after graduating from college, he was not drafted for service in Vietnam because he received a draft lottery number of 346 (out of 366).",
"title": "Early life and career"
},
{
"paragraph_id": 5,
"text": "Letterman began his broadcasting career as an announcer and newscaster at the college's student-run radio station—WBST—a 10-watt campus station that is now part of Indiana Public Radio. He was fired for treating classical music with irreverence. He then became involved with the founding of another campus station—WAGO-AM 570 (now WCRD, 91.3).",
"title": "Early life and career"
},
{
"paragraph_id": 6,
"text": "He credits Paul Dixon, host of the Paul Dixon Show, a Cincinnati-based talk show also shown in Indianapolis while he was growing up, for inspiring his choice of career:",
"title": "Early life and career"
},
{
"paragraph_id": 7,
"text": "I was just out of college [in 1969], and I really didn't know what I wanted to do. And then all of a sudden I saw him doing it [on TV]. And I thought: That's really what I want to do!",
"title": "Early life and career"
},
{
"paragraph_id": 8,
"text": "Soon after graduating from Ball State in 1969, Letterman began his career as a radio talk show host on WNTS (AM) and on Indianapolis television station WLWI (which changed its call sign to WTHR in 1976) as an anchor and weatherman. He received some attention for his unpredictable on-air behavior, which included congratulating a tropical storm for being upgraded to a hurricane and predicting hailstones \"the size of canned hams.\" He also occasionally reported the weather and the day's very high and low temps for fictitious cities (\"Eight inches of snow in Bingree and surrounding areas\"), on another occasion saying that the state border between Indiana and Ohio had been erased when a satellite map accidentally omitted it, attributing it to dirty political dealings. (\"The higher-ups have removed the border between Indiana and Ohio, making it one giant state. Personally, I'm against it. I don't know what to do about it.\") He also starred in a local kiddie show, made wisecracks as host of a late-night TV show called \"Freeze-Dried Movies\" (he once acted out a scene from Godzilla using plastic dinosaurs), and hosted a talk show that aired early on Saturday mornings called Clover Power, in which he interviewed 4-H members about their projects.",
"title": "Early life and career"
},
{
"paragraph_id": 9,
"text": "In 1971, Letterman appeared as a pit road reporter for ABC Sports' tape-delayed coverage of the Indianapolis 500, which was his first nationally telecast appearance (WLWI was the local ABC affiliate at the time). He was initially introduced as Chris Economaki, but this was corrected at the end of the interview (Jim McKay announced his name as Dave Letterman). Letterman interviewed Mario Andretti, who had just crashed out of the race.",
"title": "Early life and career"
},
{
"paragraph_id": 10,
"text": "In 1975, encouraged by his then-wife Michelle and several of his Sigma Chi fraternity brothers, Letterman moved to Los Angeles, California, with the hope of becoming a comedy writer. He and Michelle packed their belongings in his pickup truck and headed west. As of 2012, he still owned the truck. In Los Angeles, he began performing comedy at The Comedy Store. Jimmie Walker saw him on stage; with an endorsement from George Miller, Letterman joined a group of comedians whom Walker hired to write jokes for his stand-up act, a group that at various times also included Jay Leno, Paul Mooney, Robert Schimmel, Richard Jeni, Louie Anderson, Elayne Boosler, Byron Allen, Jack Handey, and Steve Oedekerk.",
"title": "Early life and career"
},
{
"paragraph_id": 11,
"text": "By the summer of 1977, Letterman was a writer and regular on the six-week summer series The Starland Vocal Band Show, broadcast on CBS. He hosted a 1977 pilot for a game show called The Riddlers (which was never picked up), and co-starred in the Barry Levinson-produced comedy special Peeping Times, which aired in January 1978. Later that year, Letterman was a cast member on Mary Tyler Moore's variety show, Mary. He made a guest appearance on Mork & Mindy (as a parody of EST leader Werner Erhard) and appearances on game shows such as The $20,000 Pyramid, The Gong Show, Hollywood Squares, Password Plus, and Liar's Club, as well as the Canadian cooking show Celebrity Cooks (November 1977), talk shows such as 90 Minutes Live (February 24 and April 14, 1978), and The Mike Douglas Show (April 3, 1979 and February 7, 1980). He was also screen tested for the lead role in the 1980 film Airplane!, a role that eventually went to Robert Hays.",
"title": "Early life and career"
},
{
"paragraph_id": 12,
"text": "Letterman's brand of dry, sarcastic humor caught the attention of scouts for The Tonight Show Starring Johnny Carson, and he was soon a regular guest on the show. He became a favorite of Carson and was a regular guest host for the show beginning in 1978. Letterman credits Carson as the person who influenced his career the most.",
"title": "Early life and career"
},
{
"paragraph_id": 13,
"text": "On June 23, 1980, Letterman was given his own morning comedy show on NBC, The David Letterman Show. It was originally 90 minutes long but was shortened to 60 minutes in August 1980. The show was a critical success, winning two Emmy Awards, but was a ratings disappointment and was canceled, the last show airing October 24, 1980.",
"title": "NBC"
},
{
"paragraph_id": 14,
"text": "NBC kept Letterman on its payroll to try him in a different time slot. Late Night with David Letterman debuted February 1, 1982; the first guest was Bill Murray. Murray went on to become one of Letterman's most recurrent guests, guesting on his later CBS show's celebration of his 30th anniversary in late-night television, which aired January 31, 2012, and on the final CBS show, which aired May 20, 2015. The show ran Monday through Thursday nights at 12:30 a.m. Eastern Time, immediately following The Tonight Show Starring Johnny Carson (a Friday night broadcast was added in June 1987). It was seen as edgy and unpredictable, and soon developed a cult following (particularly among college students). Letterman's reputation as an acerbic interviewer was borne out in verbal sparring matches with Cher (who even called him an \"asshole\" on the show), Shirley MacLaine, Charles Grodin, and Madonna. The show also featured comedy segments and running characters, in a style heavily influenced by the 1950s and 1960s programs of Steve Allen.",
"title": "NBC"
},
{
"paragraph_id": 15,
"text": "The show often featured quirky, genre-mocking regular features, including \"Stupid Pet Tricks\" (which had its origins on Letterman's morning show), Stupid Human Tricks, dropping various objects off the roof of a five-story building, demonstrations of unorthodox clothing (such as suits made of Alka-Seltzer, Velcro and suet), a recurring Top 10 list, the Monkey-Cam (and the Audience Cam), a facetious letter-answering segment, several \"Film[s] by My Dog Bob\" in which a camera was mounted on Letterman's own dog (often with comic results) and Small Town News, all of which moved with Letterman to CBS.",
"title": "NBC"
},
{
"paragraph_id": 16,
"text": "Other episodes included Letterman using a bullhorn to interrupt a live interview on The Today Show on August 19, 1985, announcing that he was the NBC News president Lawrence K. Grossman and that he was not wearing any pants; walking across the hall to Studio 6B, at the time the news studio for WNBC-TV, and interrupting Al Roker's weather segments during Live at Five; and staging \"elevator races\", complete with commentary by NBC Sports' Bob Costas. In one appearance, in 1982, Andy Kaufman (who was wearing a neck brace) appeared with professional wrestler Jerry Lawler, who slapped and knocked the comedian to the ground (Lawler and Kaufman's friend Bob Zmuda later revealed that the incident was staged).",
"title": "NBC"
},
{
"paragraph_id": 17,
"text": "In 1992, Johnny Carson retired, and many fans, and Carson himself, believed that Letterman would become the new host of The Tonight Show. When NBC instead gave the job to Jay Leno, Letterman departed NBC to host his own late-night show on CBS, opposite The Tonight Show at 11:30 p.m., called the Late Show with David Letterman. The new show debuted on August 30, 1993, and was taped at the historic Ed Sullivan Theater, where Ed Sullivan broadcast his eponymous variety series from 1948 to 1971. For Letterman's arrival, CBS spent $8 million in renovations. CBS also signed Letterman to a three-year, $14 million/year contract, doubling his Late Night salary.",
"title": "CBS"
},
{
"paragraph_id": 18,
"text": "But while the expectation was that Letterman would retain his unique style and sense of humor with the move, Late Show was not an exact replica of his old NBC program. The monologue was lengthened. Paul Shaffer and the World's Most Dangerous Band followed Letterman to CBS, but they added a brass section and were rebranded the CBS Orchestra (at Shaffer's request); a small band had been mandated by Carson while Letterman occupied the 12:30 slot. Additionally, because of intellectual property disagreements, Letterman was unable to import many of his Late Night segments verbatim, but he sidestepped this problem by simply renaming them (the \"Top Ten List\" became the \"Late Show Top Ten\", \"Viewer Mail\" became the \"CBS Mailbag\", etc.). Time magazine wrote, \"Letterman's innovation ... gained power from its rigorous formalism\"; as his biographer Jason Zinoman puts it, he was \"a fascinatingly disgruntled eccentric trapped inside a more traditional talk show.\"",
"title": "CBS"
},
{
"paragraph_id": 19,
"text": "The Late Show's main competitor was NBC's The Tonight Show, which Jay Leno hosted for 22 years from 1992 to 2014, except from June 1, 2009, to January 22, 2010, when Conan O'Brien hosted. In 1993 and 1994, the Late Show consistently gained higher ratings than The Tonight Show. But in 1995, ratings dipped and Leno's show consistently beat Letterman's in the ratings from the time that Hugh Grant came on Leno's show after Grant's arrest for soliciting a prostitute.",
"title": "CBS"
},
{
"paragraph_id": 20,
"text": "Leno typically attracted about five million nightly viewers between 1999 and 2009. The Late Show lost nearly half its audience during its competition with Leno, attracting 7.1 million viewers nightly in its 1993–94 season and about 3.8 million per night as of Leno's departure in 2009. In the final months of his first stint as host of The Tonight Show, Leno beat Letterman in the ratings by a 1.3 million-viewer margin (5.2 million to 3.9 million), and Nightline and the Late Show were virtually tied. Once O'Brien took over Tonight, Letterman closed the gap in the ratings. O'Brien initially drove the median age of Tonight Show viewers from 55 to 45, with most older viewers opting to watch the Late Show instead. After Leno returned to The Tonight Show, Leno regained his lead.",
"title": "CBS"
},
{
"paragraph_id": 21,
"text": "Letterman's shows have garnered both critical and industry praise, receiving 67 Emmy Award nominations, winning 12 times in his first 20 years in late night television. From 1993 to 2009, Letterman ranked higher than Leno in the annual Harris Poll of Nation's Favorite TV Personality 12 times. For example, in 2003 and 2004 Letterman ranked second in that poll, behind only Oprah Winfrey, a year that Leno was ranked fifth. Leno was higher than Letterman on that poll three times during the same period, in 1998, 2007, and 2008.",
"title": "CBS"
},
{
"paragraph_id": 22,
"text": "On March 27, 1995, Letterman hosted the 67th Academy Awards ceremony. Critics blasted what they deemed his poor performance, noting that his irreverent style undermined the traditional importance and glamor of the event. In a joke about their unusual names (inspired by a celebrated comic essay in The New Yorker, \"Yma Dream\" by Thomas Meehan), he started off by introducing Uma Thurman to Oprah Winfrey, and then both of them to Keanu Reeves: \"Oprah...Uma. Uma...Oprah,\" \"Have you kids met Keanu?\" This and many of his other jokes fell flat. Although Letterman attracted the highest ratings to the annual telecast since 1983, many felt that the bad publicity he generated caused a decline in the Late Show's ratings.",
"title": "CBS"
},
{
"paragraph_id": 23,
"text": "Letterman recycled the apparent debacle into a long-running gag. On his first show after the Oscars, he joked, \"Looking back, I had no idea that thing was being televised.\" He lampooned his stint two years later, during Billy Crystal's opening Oscar skit, which also parodied the plane-crashing scenes from that year's chief nominated film, The English Patient.",
"title": "CBS"
},
{
"paragraph_id": 24,
"text": "For years afterward, Letterman recounted his hosting the Oscars, although the Academy of Motion Picture Arts and Sciences continued to hold Letterman in high regard and invited him to host the Oscars again. On September 7, 2010, he made an appearance on the premiere of the 14th season of The View, and confirmed that he had been considered for hosting again.",
"title": "CBS"
},
{
"paragraph_id": 25,
"text": "On January 14, 2000, a routine check-up revealed that an artery in Letterman's heart was severely obstructed. He was rushed to emergency surgery for a quintuple bypass at New York Presbyterian Hospital. During the initial weeks of his recovery, reruns of the Late Show were shown and introduced by friends of Letterman including Norm Macdonald, Drew Barrymore, Ray Romano, Robin Williams, Bonnie Hunt, Megan Mullally, Bill Murray, Regis Philbin, Charles Grodin, Nathan Lane, Julia Roberts, Bruce Willis, Jerry Seinfeld, Martin Short, Steven Seagal, Hillary Clinton, Danny DeVito, Steve Martin, and Sarah Jessica Parker.",
"title": "CBS"
},
{
"paragraph_id": 26,
"text": "Subsequently, while still recovering from surgery, Letterman revived the late-night talk show tradition of \"guest hosts\" that had virtually disappeared on network television during the 1990s, allowing Bill Cosby, Kathie Lee Gifford, Dana Carvey, Janeane Garofalo, and others to host new episodes of the Late Show. Upon his return to the show on February 21, 2000, Letterman brought all but one of the doctors and nurses on stage who had participated in his surgery and recovery (with extra teasing of a nurse who had given him bed baths—\"This woman gave me a bath!\"), including Dr. O. Wayne Isom and physician Louis Aronne, who frequently appeared on the show.",
"title": "CBS"
},
{
"paragraph_id": 27,
"text": "For a number of episodes, Letterman continued to crack jokes about his bypass, including saying, \"Bypass surgery: it's when doctors surgically create new blood flow to your heart. A bypass is what happened to me when I didn't get The Tonight Show! It's a whole different thing.\" In a later running gag, he lobbied Indiana to rename the freeway circling Indianapolis (I-465) \"The David Letterman Bypass\". He also featured a montage of faux news coverage of his bypass surgery, which included a clip of Letterman's heart for sale on the Home Shopping Network. Letterman became friends with his doctors and nurses. In 2008, a Rolling Stone interview stated",
"title": "CBS"
},
{
"paragraph_id": 28,
"text": "he hosted a doctor and nurse who'd helped perform the emergency quintuple-bypass heart surgery that saved his life in 2000. 'These are people who were complete strangers when they opened my chest,' he says. 'And now, eight years later, they're among my best friends.'",
"title": "CBS"
},
{
"paragraph_id": 29,
"text": "Additionally, Letterman invited the band Foo Fighters to play \"Everlong\", introducing them as \"my favorite band, playing my favorite song.\" During Letterman's last show, on which Foo Fighters appeared, Letterman said that Foo Fighters had been in the middle of a South American tour which they canceled to come play on his comeback episode.",
"title": "CBS"
},
{
"paragraph_id": 30,
"text": "Letterman again handed over the reins of the show to several guest hosts (including Bill Cosby, Brad Garrett, Whoopi Goldberg, Elvis Costello, John McEnroe, Vince Vaughn, Will Ferrell, Bonnie Hunt, Luke Wilson, and bandleader Paul Shaffer) in February 2003, when he was diagnosed with a severe case of shingles. Later that year, Letterman made regular use of guest hosts—including Tom Arnold and Kelsey Grammer—for new shows broadcast on Fridays. In March 2007, Adam Sandler, who had been scheduled to be the lead guest, served as a guest host while Letterman was ill with a stomach virus.",
"title": "CBS"
},
{
"paragraph_id": 31,
"text": "In March 2002, as Letterman's contract with CBS neared expiration, ABC offered him the time slot for long-running news program Nightline with Ted Koppel. Letterman was interested, as he believed he could never match Leno's ratings at CBS due to Letterman's complaint of weaker lead-ins from the network's late local news programs, but was reluctant to replace Koppel. He addressed his decision to re-sign on the air, stating that he was content at CBS and that he had great respect for Koppel.",
"title": "CBS"
},
{
"paragraph_id": 32,
"text": "On December 4, 2006, CBS revealed that Letterman signed a new contract to host Late Show with David Letterman through the fall of 2010. \"I'm thrilled to be continuing on at CBS,\" said Letterman. \"At my age you really don't want to have to learn a new commute.\" Letterman further joked about the subject by pulling up his right pants leg, revealing a tattoo, presumably temporary, of the ABC logo.",
"title": "CBS"
},
{
"paragraph_id": 33,
"text": "\"Thirteen years ago, David Letterman put CBS late night on the map and in the process became one of the defining icons of our network,\" said Leslie Moonves, president and CEO of CBS Corporation. \"His presence on our air is an ongoing source of pride, and the creativity and imagination that the Late Show puts forth every night is an ongoing display of the highest quality entertainment. We are truly honored that one of the most revered and talented entertainers of our time will continue to call CBS 'home.'\"",
"title": "CBS"
},
{
"paragraph_id": 34,
"text": "According to a 2007 article in Forbes magazine, Letterman earned $40 million a year. A 2009 article in The New York Times, however, said his salary was estimated at $32 million. In June 2009, Letterman's Worldwide Pants and CBS reached an agreement to continue the Late Show until at least August 2012. The previous contract had been set to expire in 2010, and the two-year extension was shorter than the typical three-year contract period negotiated in the past. Worldwide Pants agreed to lower its fee for the show, though it had remained a \"solid moneymaker for CBS\" under the previous contract.",
"title": "CBS"
},
{
"paragraph_id": 35,
"text": "On the February 3, 2011 edition of the Late Show, during an interview with Howard Stern, Letterman said he would continue to do his talk show for \"maybe two years, I think.\" In April 2012, CBS announced it had extended its contract with Letterman through 2014. His contract was subsequently extended to 2015.",
"title": "CBS"
},
{
"paragraph_id": 36,
"text": "During the taping of his show on April 3, 2014, Letterman announced that he had informed CBS president Leslie Moonves that he would retire from hosting Late Show by May 20, 2015. Later in his retirement Letterman occasionally stated, in jest, that he had been fired. It was announced soon after that comedian and political satirist Stephen Colbert would succeed Letterman. Letterman's last episode aired on May 20, 2015, and opened with a presidential sendoff featuring four of the five living American presidents, George H. W. Bush, Bill Clinton, George W. Bush, and Barack Obama, each mimicking the late president Gerald Ford's statement \"Our long national nightmare is over.\" It also featured cameos from The Simpsons and Wheel of Fortune (the latter with a puzzle saying \"Good riddance to David Letterman\"), a Top Ten List of \"things I wish I could have said to David Letterman\" performed by regular guests including Alec Baldwin, Barbara Walters, Steve Martin, Jerry Seinfeld, Jim Carrey, Chris Rock, Julia Louis-Dreyfus, Peyton Manning, Tina Fey, and Bill Murray, and closed with a montage of scenes from both his CBS and NBC series set to a live performance of \"Everlong\" by Foo Fighters.",
"title": "CBS"
},
{
"paragraph_id": 37,
"text": "The final episode of Late Show with David Letterman was watched by 13.76 million viewers in the United States with an audience share of 9.3/24, earning the show its highest ratings since following the 1994 Winter Olympics on February 25, 1994, and the show's highest demo numbers (4.1 in adults 25–54 and 3.1 in adults 18–49) since Oprah Winfrey's first Late Show appearance following the ending of her feud with Letterman on December 1, 2005. Bill Murray, who had been his first guest on Late Night, was his final guest on Late Show. In a rarity for a late-night show, it was also the highest-rated program on network television that night, beating out all prime-time shows. In total, Letterman hosted 6,080 episodes of Late Night and Late Show, surpassing friend and mentor Johnny Carson as the longest-serving late-night talk show host in U.S. television history.",
"title": "CBS"
},
{
"paragraph_id": 38,
"text": "In the months following the end of Late Show, Letterman was seen occasionally at sports events such as the Indianapolis 500, during which he submitted to an interview with a local publication. He made a surprise appearance on stage in San Antonio, Texas when he was invited up for an extended segment during Steve Martin's and Martin Short's A Very Stupid Conversation show, saying \"I retired, and...I have no regrets,\" Letterman told the crowd after walking on stage. \"I was happy. I'll make actual friends. I was complacent. I was satisfied. I was content, and then a couple of days ago Donald Trump said he was running for president. I have made the biggest mistake of my life, ladies and gentlemen\" and then delivering a Top Ten List roasting Trump's presidential campaign followed by an onstage conversation with Martin and Short. Cellphone recordings of the appearance were posted on YouTube by audience members and widely reported in the media.",
"title": "Post-Late Show"
},
{
"paragraph_id": 39,
"text": "In 2016, Letterman joined the climate change documentary show Years of Living Dangerously as one of its celebrity correspondents. In season two's premiere episode, Letterman traveled to India to investigate the country's efforts to expand its inadequate energy grid, power its booming economy, and bring electricity to 300 million citizens for the first time. He also interviewed Indian Prime Minister Narendra Modi and traveled to rural villages where power is a scarce luxury and explored the United States' role in India's energy future.",
"title": "Post-Late Show"
},
{
"paragraph_id": 40,
"text": "On April 7, 2017, Letterman gave the induction speech for the band Pearl Jam into the Rock & Roll Hall Of Fame at a ceremony held at the Barclays Center in Brooklyn, New York City. Also in 2017, Letterman and Alec Baldwin co-hosted The Essentials on Turner Classic Movies. Letterman and Baldwin introduced seven films for the series.",
"title": "Post-Late Show"
},
{
"paragraph_id": 41,
"text": "In 2018, Letterman began hosting a six-episode monthly series of hour-long programs on Netflix consisting of long-form interviews and field segments. The show, My Next Guest Needs No Introduction with David Letterman, premiered January 12, 2018 with Barack Obama as its first guest. The second season premiered on May 31, 2019. Season 3 premiered on October 21, 2020, and includes Kim Kardashian West, Robert Downey Jr., Dave Chappelle and Lizzo as guests. Season 4 premiered on May 20, 2022, with Billie Eilish as the first guest. In October 2022, Letterman traveled to Kyiv, Ukraine, to film a special standalone episode of My Next Guest Needs No Introduction with David Letterman, interviewing Ukrainian president Volodymyr Zelenskyy.",
"title": "Post-Late Show"
},
{
"paragraph_id": 42,
"text": "In spite of Johnny Carson's clear intention to pass his title to Letterman, NBC selected Jay Leno to host The Tonight Show after Carson's departure. Letterman maintained a close relationship with Carson through his break with NBC. Three years after he left for CBS, HBO produced a made-for-television movie called The Late Shift, based on a book by The New York Times reporter Bill Carter, chronicling the battle between Letterman and Leno for the Tonight Show hosting spot.",
"title": "Notable exchanges and incidents"
},
{
"paragraph_id": 43,
"text": "Carson later made a few cameo appearances as a guest on Letterman's show. Carson's final television appearance was on May 13, 1994, on a Late Show episode taped in Los Angeles, when he made a surprise appearance during a Top 10 list segment. In early 2005, it was revealed that Carson occasionally sent jokes to Letterman, who used them in his monologue; according to CBS senior vice president Peter Lassally (a onetime producer for both men), Carson got \"a big kick out of it.\" Letterman would do a characteristic Carson golf swing after delivering one of his jokes. In a tribute to Carson, all the opening monologue jokes during the first show after Carson's death were by Carson.",
"title": "Notable exchanges and incidents"
},
{
"paragraph_id": 44,
"text": "Lassally also claimed that Carson had always believed Letterman, not Leno, to be his \"rightful successor\". During the early years of the Late Show's run, Letterman occasionally used some of Carson's trademark bits, including \"Carnac the Magnificent\" (with Paul Shaffer as Carnac), \"Stump the Band\", and the \"Week in Review\".",
"title": "Notable exchanges and incidents"
},
{
"paragraph_id": 45,
"text": "Oprah Winfrey appeared on Letterman's show when he was hosting NBC's Late Night on May 2, 1989. After that appearance, the two had a 16-year feud that arose, as Winfrey explained to Letterman after it had been resolved, as a result of the acerbic tone of their 1989 interview, of which she said that it \"felt so uncomfortable to me that I didn't want to have that experience again\". The feud apparently ended on December 2, 2005, when Winfrey appeared on CBS's Late Show with David Letterman in an event Letterman jokingly called \"the Super Bowl of Love\".",
"title": "Notable exchanges and incidents"
},
{
"paragraph_id": 46,
"text": "Winfrey and Letterman also appeared together in a Late Show promo aired during CBS's coverage of Super Bowl XLI in February 2007, with the two sitting next to each other on a couch watching the game. Since the game was played between the Indianapolis Colts and Chicago Bears, the Indianapolis-born Letterman wore a Peyton Manning jersey, while Winfrey, whose show was taped in Chicago, wore a Brian Urlacher jersey. On September 10, 2007, Letterman made his first appearance on The Oprah Winfrey Show at Madison Square Garden in New York City.",
"title": "Notable exchanges and incidents"
},
{
"paragraph_id": 47,
"text": "Three years later, during CBS's coverage of Super Bowl XLIV between the Colts and the New Orleans Saints, the two appeared again in a Late Show promo, this time with Winfrey sitting on a couch between Letterman and Leno. Letterman wore the retired No. 70 jersey of Art Donovan, a member of the Colts' Hall of Fame and a regular Letterman guest. The appearance was Letterman's idea: Leno flew to New York City on an NBC corporate jet, sneaking into the Ed Sullivan Theater during the Late Show's February 4 taping wearing a disguise and meeting Winfrey and Letterman at a living room set created in the theater's balcony, where they taped their promo.",
"title": "Notable exchanges and incidents"
},
{
"paragraph_id": 48,
"text": "Winfrey interviewed Letterman in January 2013 on Oprah's Next Chapter. They discussed their feud and Winfrey revealed that she had had a \"terrible experience\" while appearing on Letterman's show years earlier. Letterman could not recall the incident but apologized.",
"title": "Notable exchanges and incidents"
},
{
"paragraph_id": 49,
"text": "Late Show went off air for eight weeks in 2007 during November and December because of the Writers Guild of America strike. Letterman's production company, Worldwide Pants, was the first company to make an individual agreement with the WGA, allowing his show to come back on the air on January 2, 2008. In his first episode back, he surprised the audience with a newly grown beard, which signified solidarity with the strike. His beard was shaved off during the show on January 7, 2008.",
"title": "Notable exchanges and incidents"
},
{
"paragraph_id": 50,
"text": "On June 8 and 9, 2009, Letterman told two sexually themed jokes about a daughter (never named) of Sarah Palin on his TV show. These included a statutory rape joke about Palin's then 14-year-old daughter, Willow, and MLB player Alex Rodriguez. Palin was in New York City at the time with Willow, and none of her other children were at the game.",
"title": "Notable exchanges and incidents"
},
{
"paragraph_id": 51,
"text": "In a statement posted on the Internet, Palin said, \"I doubt [Letterman would] ever dare make such comments about anyone else's daughter\" and that \"laughter incited by sexually perverted comments made by a 62-year-old male celebrity aimed at a 14-year-old girl is disgusting.\" On his June 10 show, Letterman responded to the controversy, saying the jokes were meant to be about Palin's 18-year-old daughter, Bristol, whose pregnancy as an unmarried teenager had caused some controversy during the United States presidential election of 2008. \"These are not jokes made about [Palin's] 14-year-old daughter ... I would never, never make jokes about raping or having sex of any description with a 14-year-old girl.\"",
"title": "Notable exchanges and incidents"
},
{
"paragraph_id": 52,
"text": "His remarks did not end public criticism. The National Organization for Women (NOW) released a statement supporting Palin, noting that Letterman had made \"[only] something of an apology.\" When the controversy failed to subside, Letterman addressed the issue again on his June 15 show, faulting himself for the error and apologizing \"especially to the two daughters involved, Bristol and Willow, and also to the governor and her family and everybody else who was outraged by the joke.\" Rodriguez demanded an apology for implying that he was a child molester. Letterman never specifically apologized to Rodriguez.",
"title": "Notable exchanges and incidents"
},
{
"paragraph_id": 53,
"text": "On August 17, 2011, it was reported that an Islamist militant had posted a death threat against Letterman on a website frequented by Al-Qaeda supporters, calling on American Muslims to kill him for making a joke about the death of Ilyas Kashmiri, an Al-Qaeda leader who was killed in a June 2011 drone strike in Pakistan. In his August 22 show, Letterman joked about the threat, saying \"State Department authorities are looking into this. They're not taking this lightly. They're looking into it. They're questioning, they're interrogating, there's an electronic trail—but everybody knows it's Leno.\"",
"title": "Notable exchanges and incidents"
},
{
"paragraph_id": 54,
"text": "Letterman appeared in the pilot episode of the short-lived 1986 series Coach Toast, and appears with a bag over his head as a guest on Bonnie Hunt's 1990s sitcom The Building. He appeared in The Simpsons as himself in a couch gag when the Simpsons find themselves (and the couch) in Late Night with David Letterman. He had a cameo in the feature film Cabin Boy, with Chris Elliott, who worked as a writer for Letterman. In this and other appearances, Letterman is listed in the credits as \"Earl Hofert\", the name of Letterman's maternal grandfather. He also appeared as himself in the Howard Stern biographical film Private Parts and the 1999 Andy Kaufman biopic Man on the Moon, in a few episodes of Garry Shandling's 1990s TV series The Larry Sanders Show, and in \"The Abstinence\", a 1996 episode of the sitcom Seinfeld.",
"title": "Appearances in other media"
},
{
"paragraph_id": 55,
"text": "Letterman provided vocals for the Warren Zevon song \"Hit Somebody\" from My Ride's Here, and provided the voice for Butt-head's father in the 1996 animated film Beavis and Butt-Head Do America, again credited as Earl Hofert.",
"title": "Appearances in other media"
},
{
"paragraph_id": 56,
"text": "Letterman was the focus of The Avengers on \"Late Night with David Letterman\", issue 239 (January 1984) of the Marvel comic book series The Avengers, in which the title characters (specifically Hawkeye, Wonder Man, Black Widow, Beast, and Black Panther) are guests on Late Night. A parody of Letterman named David Endochrine is gassed to death along with his bandleader, Paul, and their audience in Frank Miller's The Dark Knight Returns. In SWAT Kats: The Radical Squadron, Letterman was parodied as \"David Litterbin\". Letterman appears in issues 13–14 and 18 of Harvey Pekar's autobiographical comic book American Splendor. Those issues show Pekar's accounts of appearances on Late Night.",
"title": "Appearances in other media"
},
{
"paragraph_id": 57,
"text": "In 2010, a documentary directed by Joke Fincioen and Biagio Messina, Dying to do Letterman, was released, featuring Steve Mazan, a standup comic, who has cancer and wants to appear on Letterman's show. The film won best documentary and jury awards at the Cinequest Film Festival. Mazan published a book of the same name (full title Dying to Do Letterman: Turning Someday into Today) about his own saga.",
"title": "Appearances in other media"
},
{
"paragraph_id": 58,
"text": "Letterman appeared as a guest on CNN's Piers Morgan Tonight on May 29, 2012, when he was interviewed by Regis Philbin, the guest host and Letterman's longtime friend. Philbin again interviewed Letterman (and Shaffer) while guest-hosting CBS's The Late Late Show (between the tenures of Craig Ferguson and James Corden) on January 27, 2015. In June 2013, Letterman appeared in the second episode of season two of Comedians in Cars Getting Coffee. On November 5, 2013, he and Bruce McCall published a fiction satire book, This Land Was Made for You and Me (But Mostly Me), ISBN 0-399-16368-9.",
"title": "Appearances in other media"
},
{
"paragraph_id": 59,
"text": "In Week 13 of the 2021 NFL season, Letterman joined Peyton and Eli Manning on their Manningcast feed of the Monday Night Football game between the New England Patriots and Buffalo Bills. Letterman mocked Bill Belichick after he was caught on camera wiping his nose with his shirt and was in the middle of recalling being with Roger Goodell when Goodell was booed at the unveiling of Peyton Manning's statue in Indianapolis when ESPN suddenly cut to commercials.",
"title": "Appearances in other media"
},
{
"paragraph_id": 60,
"text": "On February 1, 2022, Letterman was the guest on Late Night with Seth Meyers, marking the 40th anniversary of the franchise's debut.",
"title": "Appearances in other media"
},
{
"paragraph_id": 61,
"text": "On November 20, 2023, Letterman returned to the Ed Sullivan theater on The Late Show with Stephen Colbert.",
"title": "Appearances in other media"
},
{
"paragraph_id": 62,
"text": "Letterman started his production company, Worldwide Pants Incorporated, which produced his show and several others, in 1991. The company also produces feature films and documentaries and founded its own record label, Clear Entertainment. Worldwide Pants received significant attention in December 2007 after it was announced that it had independently negotiated its own contract with the Writers Guild of America, East, thus allowing Letterman, Craig Ferguson, and their writers to return to work, while the union continued its strike against production companies, networks, and studios with whom it had not yet reached agreements.",
"title": "Business ventures"
},
{
"paragraph_id": 63,
"text": "Letterman, Bobby Rahal, and Mike Lanigan co-own Rahal Letterman Lanigan Racing, an auto racing team competing in the WeatherTech SportsCar Championship and NTT IndyCar series. The team has twice won the Indianapolis 500: in 2004 with driver Buddy Rice, and in 2020 with Takuma Sato.",
"title": "Business ventures"
},
{
"paragraph_id": 64,
"text": "The Letterman Foundation for Courtesy and Grooming is a private foundation through which Letterman has donated millions of dollars to charities and other nonprofit organizations in Indiana and Montana, celebrity-affiliated organizations such as Paul Newman's Hole in the Wall Gang Camp, Ball State University, the American Cancer Society, the Salvation Army, and Médecins Sans Frontières.",
"title": "Business ventures"
},
{
"paragraph_id": 65,
"text": "Letterman's biggest influence and mentor was Johnny Carson. Other comedians who influenced Letterman were Paul Dixon, Steve Allen, Jonathan Winters, Garry Moore, Jack Paar, Don Rickles, and David Brenner. Although Ernie Kovacs has also been mentioned as an influence, Letterman has denied this.",
"title": "Influences"
},
{
"paragraph_id": 66,
"text": "Comedians influenced by Letterman include Conan O'Brien, Jon Stewart, Stephen Colbert, Ray Romano, Jimmy Kimmel, Jay Leno, Arsenio Hall, Larry Wilmore, Seth Meyers, Norm Macdonald, Jimmy Fallon, John Oliver, and James Corden.",
"title": "Influences"
},
{
"paragraph_id": 67,
"text": "Letterman has tinnitus, a symptom of hearing loss. On the Late Show in 1996, he talked about his experience with tinnitus during an interview with William Shatner, who has severe tinnitus caused by an on-set explosion. Letterman has said that he was initially unable to pinpoint the noise inside his head and that he hears a constant ringing in his ears.",
"title": "Personal life"
},
{
"paragraph_id": 68,
"text": "Letterman no longer drinks alcohol. On more than one occasion, he said that he had once been a \"horrible alcoholic\" and had begun drinking around the age of 13 and continued until 1981 when he was 34. He has said that in 1981, \"I was drunk 80% of the time ... I loved it. I was one of those guys, I looked around, and everyone else had stopped drinking and I couldn't understand why.\" When he was shown drinking what appears to be alcohol on Late Night or the Late Show, it was actually apple juice.",
"title": "Personal life"
},
{
"paragraph_id": 69,
"text": "In 2015, Letterman said of his anxiety: \"For years and years and years—30, 40 years—I was anxious and hypochondriacal and an alcoholic, and many, many other things that made me different from other people.\" He became calmer through a combination of Transcendental Meditation and low doses of medication. Letterman is a Presbyterian, a religious tradition he was originally brought up in by his mother, though he once said he was motivated by \"Lutheran, Midwestern guilt\".",
"title": "Personal life"
},
{
"paragraph_id": 70,
"text": "In August 2021, Letterman was hospitalized in Providence, Rhode Island, after hitting his head on the sidewalk and falling unconscious. He favorably recalled the care he received at Rhode Island Hospital in a video released by the hospital's owner.",
"title": "Personal life"
},
{
"paragraph_id": 71,
"text": "On July 2, 1968, Letterman married his college sweetheart, Michelle Cook, in Muncie, Indiana; they divorced by October 1977. He also had a long-term cohabiting relationship with the former head writer and producer on Late Night, Merrill Markoe, from 1978 to 1988. Markoe created several Late Night staples, such as \"Stupid Pet/Human Tricks\". Time magazine wrote that theirs was the defining relationship of Letterman's career, with Markoe also acting as his writing partner. She \"put the surrealism in Letterman's comedy.\"",
"title": "Personal life"
},
{
"paragraph_id": 72,
"text": "Letterman and Regina Lasko started dating in February 1986, while he was still living with Markoe. Lasko gave birth to their son, Harry Joseph Letterman, on November 3, 2003. Harry is named after Letterman's father. In 2005, police discovered a plot to kidnap Letterman's son and demand a $5 million ransom. Kelly Frank, a house painter who had worked for Letterman, was charged in the conspiracy.",
"title": "Personal life"
},
{
"paragraph_id": 73,
"text": "Letterman and Lasko wed on March 19, 2009, in a quiet courthouse civil ceremony in Choteau, Montana, where he had purchased a ranch in 1999. Letterman announced the marriage during the taping of his show of March 23, shortly after congratulating Bruce Willis on his marriage the week before. Letterman told the audience he nearly missed the ceremony because his truck became stuck in mud two miles from their house. The family resides in North Salem, New York, on a 108-acre (44-hectare) estate.",
"title": "Personal life"
},
{
"paragraph_id": 74,
"text": "",
"title": "Personal life"
},
{
"paragraph_id": 75,
"text": "On October 1, 2009, Letterman announced on his show that he had been the victim of a blackmail attempt by a person threatening to reveal his sexual relationships with several of his female employees—a fact Letterman immediately thereafter confirmed. He said that someone had left a package in his car with material he said he would write into a screenplay and a book if Letterman did not pay him $2 million. Letterman said that he contacted the Manhattan District Attorney's office and partook in a sting operation that involved the handover of a fake check to the extortionist.",
"title": "Personal life"
},
{
"paragraph_id": 76,
"text": "Joe Halderman, a producer of the CBS news magazine television series 48 Hours, was arrested around noon (EST) on October 1, 2009, after trying to deposit the check. He was indicted by a Manhattan grand jury following testimony from Letterman and pleaded not guilty to a charge of attempted grand larceny on October 2, 2009. Halderman pleaded guilty in March 2010 and was sentenced to six months in prison, followed by probation and community service.",
"title": "Personal life"
},
{
"paragraph_id": 77,
"text": "A central figure in the case and one of the women with whom Letterman had had a sexual relationship was his longtime personal assistant Stephanie Birkitt, who often appeared on the show. She had also worked for 48 Hours. Until a month before the revelations, she had shared a residence with Halderman, who allegedly had copied her personal diary and used it, along with private emails, in the blackmail package.",
"title": "Personal life"
},
{
"paragraph_id": 78,
"text": "In the days following the initial announcement of the affairs and the arrest, several prominent women, including Kathie Lee Gifford, co-host of NBC's Today Show, and NBC news anchor Ann Curry, questioned whether Letterman's affairs with subordinates created an unfair working environment. A spokesman for Worldwide Pants said that the company's sexual harassment policy did not prohibit sexual relationships between managers and employees. According to business news reporter Eve Tahmincioglu, \"CBS suppliers are supposed to follow the company's business conduct policies\" and the CBS 2008 Business Conduct Statement states that \"If a consenting romantic or sexual relationship between a supervisor and a direct or indirect subordinate should develop, CBS requires the supervisor to disclose this information to his or her Company's Human Resources Department\".",
"title": "Personal life"
},
{
"paragraph_id": 79,
"text": "On October 3, 2009, TMZ reported that a former CBS employee, Holly Hester, had had a yearlong secret affair with Letterman in the early 1990s while she was his intern and a student at New York University. On October 5, 2009, Letterman devoted a segment of his show to a public apology to his wife and staff. Three days later, Worldwide Pants announced that Birkitt had been placed on a \"paid leave of absence\" from the Late Show.",
"title": "Personal life"
},
{
"paragraph_id": 80,
"text": "Beginning in May 1988, Letterman was stalked by Margaret Mary Ray, a woman with schizophrenia. She stole his Porsche, camped out on his tennis court, and repeatedly broke into his house. Her exploits drew national attention, with Letterman occasionally joking about her on his show, though he never named her. After she died by suicide at age 46 in October 1998, Letterman told The New York Times that he had great compassion for her. A spokesperson for Letterman said: \"This is a sad ending to a confused life.\"",
"title": "Personal life"
},
{
"paragraph_id": 81,
"text": "In 2005, a woman was able to obtain a restraining order from a New Mexico judge, prohibiting Letterman from contacting her. She claimed he had sent her coded messages via his television program, causing her bankruptcy and emotional distress. Law professor Eugene Volokh called the case \"patently frivolous\".",
"title": "Personal life"
},
{
"paragraph_id": 82,
"text": "Letterman is a car enthusiast and owns an extensive collection. In 2012, it was reported that the collection consisted of ten Ferraris, eight Porsches, four Austin-Healeys, two Honda motorcycles, a Chevy pickup, and one car each from automakers Mercedes-Benz, Jaguar, MG, Volvo, and Pontiac.",
"title": "Personal life"
},
{
"paragraph_id": 83,
"text": "In his 2013 appearance on Comedians in Cars Getting Coffee, part of Jerry Seinfeld's conversation with Letterman was filmed in Letterman's 1995 Volvo 960 station wagon, which is powered by a 380-horsepower racing engine. Paul Newman had the car built for Letterman.",
"title": "Personal life"
},
{
"paragraph_id": 84,
"text": "Letterman shares a close relationship with the rock band Foo Fighters since its appearance on his first show upon his return from heart surgery. The band appeared many times on the Late Show, including a week-long stint in October 2014. While introducing the band's performance of \"Miracle\" on the show of October 17, 2014, Letterman told the story of how a souvenir video of himself and his four-year-old son learning to ski used the song as background music, unbeknownst to Letterman until he saw it. He stated: \"This is the second song of theirs that will always have great, great meaning for me for the rest of my life\". This was the first time the band had heard this story. Worldwide Pants co-produced Dave Grohl's Sonic Highways TV series. \"Letterman was the first person to get behind this project,\" Grohl said.",
"title": "Personal life"
},
{
"paragraph_id": 85,
"text": "David Letterman Communication and Media Building",
"title": "Awards, honors and legacy"
},
{
"paragraph_id": 86,
"text": "In 1996, Letterman was ranked 45th on TV Guide's 50 Greatest TV Stars of All Time. In 2002, The Late Show with David Letterman was ranked seventh on TV Guide's 50 Greatest TV Shows of All Time.",
"title": "Awards, honors and legacy"
},
{
"paragraph_id": 87,
"text": "On September 7, 2007, Letterman visited his alma mater, Ball State University in Muncie, Indiana, for the dedication of a communications facility named in his honor for his dedication to the university. The $21 million, 75,000-square-foot (7,000 m) David Letterman Communication and Media Building opened for the 2007 fall semester. Thousands of Ball State students, faculty, and local residents welcomed Letterman back to Indiana. Letterman's emotional speech touched on his struggles as a college student and his late father, and also included the \"top ten good things about having your name on a building\", finishing with \"if reasonable people can put my name on a $21 million building, anything is possible.\" Over many years Letterman \"has provided substantial assistance to [Ball State's] Department of Telecommunications, including an annual scholarship that bears his name.\"",
"title": "Awards, honors and legacy"
},
{
"paragraph_id": 88,
"text": "At the same time, Indiana Governor Mitch Daniels gave Letterman a Sagamore of the Wabash award, which recognizes distinguished service to the state of Indiana.",
"title": "Awards, honors and legacy"
},
{
"paragraph_id": 89,
"text": "Awards and nominations",
"title": "Awards, honors and legacy"
},
{
"paragraph_id": 90,
"text": "In his capacities as a performer, producer, or as part of a writing team, Letterman is among the most nominated people in the history of the Emmy Awards, with 52 nominations, winning two Daytime Emmys and ten Primetime Emmys since 1981. He won four American Comedy Awards and in 2011 became the first recipient of the Johnny Carson Award for Comedic Excellence at The Comedy Awards.",
"title": "Awards, honors and legacy"
},
{
"paragraph_id": 91,
"text": "Letterman was a recipient of the 2012 Kennedy Center Honors, where he was called \"one of the most influential personalities in the history of television, entertaining an entire generation of late-night viewers with his unconventional wit and charm.\" On May 16, 2017, Letterman was named the next recipient of the Mark Twain Prize for American Humor, the award granted annually by the John F. Kennedy Center for the Performing Arts. He received the prize in a ceremony on October 22, 2017.",
"title": "Awards, honors and legacy"
}
] | David Michael Letterman is an American television host, comedian, writer and producer. He hosted late-night television talk shows for 33 years, beginning with the February 1, 1982, debut of Late Night with David Letterman on NBC and ending with the May 20, 2015, broadcast of Late Show with David Letterman on CBS. In total, Letterman hosted 6,080 episodes of Late Night and Late Show, surpassing his friend and mentor Johnny Carson as the longest-serving late-night talk show host in American television history. He is also a television and film producer. His company, Worldwide Pants, produced his shows as well as The Late Late Show and several primetime comedies, the most successful of which was the CBS sitcom Everybody Loves Raymond. Several late-night hosts have cited Letterman's influence, including Conan O'Brien, Stephen Colbert, Jimmy Fallon, Jimmy Kimmel, Jon Stewart, and Seth Meyers. Since 2018 he has hosted the Netflix series My Next Guest Needs No Introduction with David Letterman. | 2001-08-20T03:37:22Z | 2023-12-23T20:09:30Z | [
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] | https://en.wikipedia.org/wiki/David_Letterman |
8,341 | Delroy Lindo | Delroy George Lindo (born 18 November 1952) is an English-American actor. He is the recipient of such accolades as a NAACP Image Award, a Satellite Award, and nominations for a Drama Desk Award, a Helen Hayes Award, a Tony Award, two Critics' Choice Television Awards, and three Screen Actors Guild Awards.
Lindo has played prominent roles in four Spike Lee films: West Indian Archie in Malcolm X (1992), Woody Carmichael in Crooklyn (1994), Rodney Little in Clockers (1995), and Paul in Da 5 Bloods (2020); he received universal acclaim for his performance in Da 5 Bloods as a Vietnam War veteran, winning the New York Film Critics Circle Award for Best Actor and the National Society of Film Critics Award for Best Actor. Lindo also played Bo Catlett in Get Shorty (1995), Arthur Rose in The Cider House Rules (1999), and Detective Castlebeck in Gone in 60 Seconds (2000). Lindo starred as Alderman Ronin Gibbons in the TV series The Chicago Code (2011), as Winter on the series Believe (2014), and as Adrian Boseman in The Good Fight (2017–2021).
Delroy Lindo was born in 1952 in Lewisham, south-east London, the son of Jamaican parents. His mother had immigrated to the UK in 1951 from Jamaica to work as a nurse, and his father worked in various jobs. Lindo grew up in nearby Eltham and attended Woolwich Polytechnic School for Boys. He became interested in acting as a child when he appeared in a nativity play at school. As a teenager, Lindo and his mother moved to Toronto, Ontario. When he was 16, they moved to San Francisco. At the age of 24, Lindo began his studies in acting at the American Conservatory Theater, graduating in 1979.
Lindo's film debut came in 1976 with the Canadian John Candy comedy Find the Lady, followed by two other roles in films, including an army sergeant in More American Graffiti (1979).
For a decade from the early 1980s Lindo's career was more focused on theatre acting than film, although he has said this was not a conscious decision. In 1982 he debuted on Broadway in "Master Harold"...and the Boys, directed by the play's South African author Athol Fugard. By 1988, Lindo had earned a Tony nomination for his portrayal of Herald Loomis in August Wilson's Joe Turner's Come and Gone.
Lindo returned to film in the science fiction film Salute of the Jugger (1990), which has become a cult classic. Although he had turned down Spike Lee for a role in Do the Right Thing, Lee cast him as Woody Carmichael in the drama Crooklyn (1994), which brought Lindo notice. His other roles with Lee include West Indian Archie, a psychotic gangster, in Malcolm X and a starring role as a neighborhood drug dealer in Clockers.
Other films in which he has starring roles are Barry Sonnenfeld's Get Shorty (1995), Ron Howard's Ransom (1996) and Soul of the Game (1996), as the baseball player Satchel Paige.
In 1998 Lindo co-starred as African-American explorer Matthew Henson, in the TV film Glory & Honor, directed by Kevin Hooks. It portrayed Henson's nearly 20-year partnership with Commander Robert Peary in Arctic exploration and their effort to find the Geographic North Pole in 1909. Lindo received a Satellite Award for best actor for his portrayal of Henson. Lindo has continued to work in television, and in 2006 was seen on the short-lived NBC drama Kidnapped.
Lindo had a small role in the 1995 film Congo, playing the corrupt Captain Wanta. Lindo was not credited for the role. He played an angel in the comedy film A Life Less Ordinary (1997).
He guest-starred on The Simpsons in the episode "Brawl in the Family", playing a character named Gabriel.
In the British film Wondrous Oblivion (2003), directed by Paul Morrison, Lindo starred as Dennis Samuels, the father of a Jamaican immigrant family in London in the 1950s. Lindo said he made the film in honor of his parents, who had similarly moved to London in those years.
In 2007, Lindo began an association with Berkeley Repertory Theatre in Berkeley, California, when he directed Tanya Barfield's play The Blue Door. In the autumn of 2008, Lindo revisited August Wilson's play Joe Turner's Come and Gone, directing a production at the Berkeley Rep. In 2010, he played the role of elderly seer Bynum in David Lan's production of Joe Turner at the Young Vic Theatre in London.
Lindo was in the main cast of the Fox crime drama The Chicago Code (2011), the NBC fantasy series Believe, and the ABC soap Blood & Oil (2015). In 2017, Lindo began playing Adrian Boseman in the CBS legal drama The Good Fight, a role he would star in for the series' first four seasons and reprise as a guest star in its fifth season. Lindo was cast as the lead in an ABC drama pilot Harlem's Kitchen in March 2020.
In 2015, Lindo was expected to play Marcus Garvey in a biopic of the black nationalist historical figure that had been in pre-production for several years. Lindo appeared in the action film Point Break (2015), the horror film Malicious (2018), the drama Battlecreek, Da 5 Bloods (2020), another collaboration with Spike Lee, and The Harder They Fall (2021) as Bass Reeves. For his role in Da 5 Bloods, Lindo received critical acclaim and a number of accolades.
Entertainment Weekly said of Hulu's comedy series Unprisoned (2023), "Delroy Lindo is so good it should be illegal."
It was announced in July 2021 that Lindo would star as Mr Nancy in the British Amazon Prime miniseries adaptation of Neil Gaiman's Anansi Boys alongside Malachi Kirby. In November, Lindo officially joined the cast of the upcoming Marvel Studios film Blade in an undisclosed role.
As of 2020, Lindo was developing a screenplay for his directorial debut about the Windrush generation.
Lindo married his wife Nashormeh Lindo in 1990. They settled down in Oakland, California, in 1996, having moved from New York City and preferring the San Francisco Bay Area to Los Angeles. Their son Damiri was born in 2001. Lindo is a football fan and supports Manchester United.
Upon learning more about the Windrush generation through his mother's story of arriving in Britain and playing a Jamaican immigrant in Wondrous Oblivion, Lindo became inspired to study the subject and history further. In 2014, he completed a master's thesis from New York University's Gallatin School. In addition, he was awarded an honorary doctorate in Arts and Humanities from Virginia Union University. | [
{
"paragraph_id": 0,
"text": "Delroy George Lindo (born 18 November 1952) is an English-American actor. He is the recipient of such accolades as a NAACP Image Award, a Satellite Award, and nominations for a Drama Desk Award, a Helen Hayes Award, a Tony Award, two Critics' Choice Television Awards, and three Screen Actors Guild Awards.",
"title": ""
},
{
"paragraph_id": 1,
"text": "Lindo has played prominent roles in four Spike Lee films: West Indian Archie in Malcolm X (1992), Woody Carmichael in Crooklyn (1994), Rodney Little in Clockers (1995), and Paul in Da 5 Bloods (2020); he received universal acclaim for his performance in Da 5 Bloods as a Vietnam War veteran, winning the New York Film Critics Circle Award for Best Actor and the National Society of Film Critics Award for Best Actor. Lindo also played Bo Catlett in Get Shorty (1995), Arthur Rose in The Cider House Rules (1999), and Detective Castlebeck in Gone in 60 Seconds (2000). Lindo starred as Alderman Ronin Gibbons in the TV series The Chicago Code (2011), as Winter on the series Believe (2014), and as Adrian Boseman in The Good Fight (2017–2021).",
"title": ""
},
{
"paragraph_id": 2,
"text": "Delroy Lindo was born in 1952 in Lewisham, south-east London, the son of Jamaican parents. His mother had immigrated to the UK in 1951 from Jamaica to work as a nurse, and his father worked in various jobs. Lindo grew up in nearby Eltham and attended Woolwich Polytechnic School for Boys. He became interested in acting as a child when he appeared in a nativity play at school. As a teenager, Lindo and his mother moved to Toronto, Ontario. When he was 16, they moved to San Francisco. At the age of 24, Lindo began his studies in acting at the American Conservatory Theater, graduating in 1979.",
"title": "Early life"
},
{
"paragraph_id": 3,
"text": "Lindo's film debut came in 1976 with the Canadian John Candy comedy Find the Lady, followed by two other roles in films, including an army sergeant in More American Graffiti (1979).",
"title": "Career"
},
{
"paragraph_id": 4,
"text": "For a decade from the early 1980s Lindo's career was more focused on theatre acting than film, although he has said this was not a conscious decision. In 1982 he debuted on Broadway in \"Master Harold\"...and the Boys, directed by the play's South African author Athol Fugard. By 1988, Lindo had earned a Tony nomination for his portrayal of Herald Loomis in August Wilson's Joe Turner's Come and Gone.",
"title": "Career"
},
{
"paragraph_id": 5,
"text": "Lindo returned to film in the science fiction film Salute of the Jugger (1990), which has become a cult classic. Although he had turned down Spike Lee for a role in Do the Right Thing, Lee cast him as Woody Carmichael in the drama Crooklyn (1994), which brought Lindo notice. His other roles with Lee include West Indian Archie, a psychotic gangster, in Malcolm X and a starring role as a neighborhood drug dealer in Clockers.",
"title": "Career"
},
{
"paragraph_id": 6,
"text": "Other films in which he has starring roles are Barry Sonnenfeld's Get Shorty (1995), Ron Howard's Ransom (1996) and Soul of the Game (1996), as the baseball player Satchel Paige.",
"title": "Career"
},
{
"paragraph_id": 7,
"text": "In 1998 Lindo co-starred as African-American explorer Matthew Henson, in the TV film Glory & Honor, directed by Kevin Hooks. It portrayed Henson's nearly 20-year partnership with Commander Robert Peary in Arctic exploration and their effort to find the Geographic North Pole in 1909. Lindo received a Satellite Award for best actor for his portrayal of Henson. Lindo has continued to work in television, and in 2006 was seen on the short-lived NBC drama Kidnapped.",
"title": "Career"
},
{
"paragraph_id": 8,
"text": "Lindo had a small role in the 1995 film Congo, playing the corrupt Captain Wanta. Lindo was not credited for the role. He played an angel in the comedy film A Life Less Ordinary (1997).",
"title": "Career"
},
{
"paragraph_id": 9,
"text": "He guest-starred on The Simpsons in the episode \"Brawl in the Family\", playing a character named Gabriel.",
"title": "Career"
},
{
"paragraph_id": 10,
"text": "In the British film Wondrous Oblivion (2003), directed by Paul Morrison, Lindo starred as Dennis Samuels, the father of a Jamaican immigrant family in London in the 1950s. Lindo said he made the film in honor of his parents, who had similarly moved to London in those years.",
"title": "Career"
},
{
"paragraph_id": 11,
"text": "In 2007, Lindo began an association with Berkeley Repertory Theatre in Berkeley, California, when he directed Tanya Barfield's play The Blue Door. In the autumn of 2008, Lindo revisited August Wilson's play Joe Turner's Come and Gone, directing a production at the Berkeley Rep. In 2010, he played the role of elderly seer Bynum in David Lan's production of Joe Turner at the Young Vic Theatre in London.",
"title": "Career"
},
{
"paragraph_id": 12,
"text": "Lindo was in the main cast of the Fox crime drama The Chicago Code (2011), the NBC fantasy series Believe, and the ABC soap Blood & Oil (2015). In 2017, Lindo began playing Adrian Boseman in the CBS legal drama The Good Fight, a role he would star in for the series' first four seasons and reprise as a guest star in its fifth season. Lindo was cast as the lead in an ABC drama pilot Harlem's Kitchen in March 2020.",
"title": "Career"
},
{
"paragraph_id": 13,
"text": "In 2015, Lindo was expected to play Marcus Garvey in a biopic of the black nationalist historical figure that had been in pre-production for several years. Lindo appeared in the action film Point Break (2015), the horror film Malicious (2018), the drama Battlecreek, Da 5 Bloods (2020), another collaboration with Spike Lee, and The Harder They Fall (2021) as Bass Reeves. For his role in Da 5 Bloods, Lindo received critical acclaim and a number of accolades.",
"title": "Career"
},
{
"paragraph_id": 14,
"text": "Entertainment Weekly said of Hulu's comedy series Unprisoned (2023), \"Delroy Lindo is so good it should be illegal.\"",
"title": "Career"
},
{
"paragraph_id": 15,
"text": "It was announced in July 2021 that Lindo would star as Mr Nancy in the British Amazon Prime miniseries adaptation of Neil Gaiman's Anansi Boys alongside Malachi Kirby. In November, Lindo officially joined the cast of the upcoming Marvel Studios film Blade in an undisclosed role.",
"title": "Career"
},
{
"paragraph_id": 16,
"text": "As of 2020, Lindo was developing a screenplay for his directorial debut about the Windrush generation.",
"title": "Career"
},
{
"paragraph_id": 17,
"text": "Lindo married his wife Nashormeh Lindo in 1990. They settled down in Oakland, California, in 1996, having moved from New York City and preferring the San Francisco Bay Area to Los Angeles. Their son Damiri was born in 2001. Lindo is a football fan and supports Manchester United.",
"title": "Personal life"
},
{
"paragraph_id": 18,
"text": "Upon learning more about the Windrush generation through his mother's story of arriving in Britain and playing a Jamaican immigrant in Wondrous Oblivion, Lindo became inspired to study the subject and history further. In 2014, he completed a master's thesis from New York University's Gallatin School. In addition, he was awarded an honorary doctorate in Arts and Humanities from Virginia Union University.",
"title": "Personal life"
}
] | Delroy George Lindo is an English-American actor. He is the recipient of such accolades as a NAACP Image Award, a Satellite Award, and nominations for a Drama Desk Award, a Helen Hayes Award, a Tony Award, two Critics' Choice Television Awards, and three Screen Actors Guild Awards. Lindo has played prominent roles in four Spike Lee films: West Indian Archie in Malcolm X (1992), Woody Carmichael in Crooklyn (1994), Rodney Little in Clockers (1995), and Paul in Da 5 Bloods (2020); he received universal acclaim for his performance in Da 5 Bloods as a Vietnam War veteran, winning the New York Film Critics Circle Award for Best Actor and the National Society of Film Critics Award for Best Actor. Lindo also played Bo Catlett in Get Shorty (1995), Arthur Rose in The Cider House Rules (1999), and Detective Castlebeck in Gone in 60 Seconds (2000). Lindo starred as Alderman Ronin Gibbons in the TV series The Chicago Code (2011), as Winter on the series Believe (2014), and as Adrian Boseman in The Good Fight (2017–2021). | 2001-08-20T04:01:18Z | 2023-12-17T01:34:49Z | [
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] | https://en.wikipedia.org/wiki/Delroy_Lindo |
8,343 | David Janssen | David Janssen (born David Harold Meyer; March 27, 1931 – February 13, 1980) was an American film and television actor who is best known for his starring role as Richard Kimble in the television series The Fugitive (1963–1967). Janssen also had the title roles in three other series: Richard Diamond, Private Detective; O'Hara, U.S. Treasury and Harry O.
In 1996 TV Guide ranked him number 36 on its 50 Greatest TV Stars of All Time list.
David Janssen was born on March 27, 1931, in Naponee, a village in Franklin County in southern Nebraska, to Harold Edward Meyer, a banker, and Berniece Graf, a former Miss Nebraska and Ziegfeld girl. Following his parents' divorce in 1935, his mother moved with five-year-old David to Los Angeles, and married Eugene Janssen in 1940. Young David used his stepfather's name after he entered show business as a child.
He attended Fairfax High School, where he excelled on the basketball court, setting a school scoring record that lasted over 20 years. His first film part was at the age of thirteen, and by the age of twenty-five he had appeared in twenty films and served two years as an enlisted man in the United States Army. During his Army days, Janssen became a friend of fellow enlistees Martin Milner and Clint Eastwood while posted at Fort Ord, California.
Janssen starred in four television series of his own:
At the time of its airing in August 1967, the final episode of The Fugitive held the record for the greatest number of American homes with television sets to watch a series finale — 72 percent. In 1996 TV Guide ranked The Fugitive number 36 on its 50 Greatest Shows of All Time list.
His films include: To Hell and Back, the biography of Audie Murphy, who was the most decorated American soldier of World War II; Hell to Eternity, a 1960 American World War II biopic starring Jeffrey Hunter as a Hispanic boy who fought in the Battle of Saipan and who was raised by Japanese-American foster parents; John Wayne's Vietnam war film The Green Berets; opposite Gregory Peck, in the space story Marooned, in which Janssen played an astronaut sent to rescue three stranded men in space; and The Shoes of the Fisherman, as a television journalist in Rome reporting on the election of a new Pope (Anthony Quinn).
He also played pilot Harry Walker in the 1973 action movie Birds of Prey. He starred as a Los Angeles police detective trying to clear himself in the killing of an apparently innocent doctor in the 1967 film Warning Shot, which was shot during a break in the spring and summer of 1966 between the third and fourth seasons of The Fugitive.
Janssen played an alcoholic in the 1977 TV movie A Sensitive, Passionate Man, which co-starred Angie Dickinson, and played an engineer who devises an unbeatable system for blackjack in the 1978 made-for-TV movie Nowhere to Run, co-starring Stefanie Powers and Linda Evans. Janssen's impressively husky voice was used to good effect as the narrator for the TV mini-series Centennial (1978–79); he also appeared in the final episode. And in 1979 he starred in the made-for-TV mini series S.O.S. Titanic as John Jacob Astor, playing opposite Beverly Ross as his wife, Madeleine.
Though Janssen's scenes were cut from the final release, he also appeared as a journalist in the film Inchon, which he accepted in order to work with Laurence Olivier, who played General Douglas MacArthur. At the time of his death, Janssen had just begun filming a television movie playing the part of Father Damien, the priest who dedicated himself to the leper colony on the island of Molokai, Hawaii. The part was eventually reassigned to actor Ken Howard of the CBS series The White Shadow.
Janssen was married twice. His first marriage was to model and interior decorator Ellie Graham, whom he married in Las Vegas on August 25, 1958. They divorced in 1968. In 1975, he married actress and model Dani Crayne Greco. They remained married until Janssen's death.
Janssen was a heavy drinker who smoked up to four packs of cigarettes a day. He died from a sudden heart attack in the early morning of February 13, 1980, at his beachfront home in Malibu, California, at the age of 48. At the time of his death, Janssen was filming the television movie Father Damien. Janssen was buried at the Hillside Memorial Park Cemetery in Culver City, California. A non-denominational funeral was held at the Jewish chapel of the cemetery on February 17. Suzanne Pleshette delivered the eulogy at the request of Janssen's widow. Milton Berle, Johnny Carson, Tommy Gallagher, Richard Harris, Stan Herman, Rod Stewart and Gregory Peck were among Janssen's pallbearers. Honorary pallbearers included Jack Lemmon, George Peppard, James Stewart and Danny Thomas.
According to friend and Fugitive co-star Barry Morse, "David Janssen was well known as one of the hardest working actors in the USA," regularly working 12–14 hours a day, and he kept working until his early death.
For his contribution to the television industry, David Janssen has a star on the Hollywood Walk of Fame located on the 7700 block of Hollywood Boulevard. | [
{
"paragraph_id": 0,
"text": "David Janssen (born David Harold Meyer; March 27, 1931 – February 13, 1980) was an American film and television actor who is best known for his starring role as Richard Kimble in the television series The Fugitive (1963–1967). Janssen also had the title roles in three other series: Richard Diamond, Private Detective; O'Hara, U.S. Treasury and Harry O.",
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},
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"text": "David Janssen was born on March 27, 1931, in Naponee, a village in Franklin County in southern Nebraska, to Harold Edward Meyer, a banker, and Berniece Graf, a former Miss Nebraska and Ziegfeld girl. Following his parents' divorce in 1935, his mother moved with five-year-old David to Los Angeles, and married Eugene Janssen in 1940. Young David used his stepfather's name after he entered show business as a child.",
"title": "Early life"
},
{
"paragraph_id": 3,
"text": "He attended Fairfax High School, where he excelled on the basketball court, setting a school scoring record that lasted over 20 years. His first film part was at the age of thirteen, and by the age of twenty-five he had appeared in twenty films and served two years as an enlisted man in the United States Army. During his Army days, Janssen became a friend of fellow enlistees Martin Milner and Clint Eastwood while posted at Fort Ord, California.",
"title": "Early life"
},
{
"paragraph_id": 4,
"text": "Janssen starred in four television series of his own:",
"title": "Acting career"
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{
"paragraph_id": 5,
"text": "At the time of its airing in August 1967, the final episode of The Fugitive held the record for the greatest number of American homes with television sets to watch a series finale — 72 percent. In 1996 TV Guide ranked The Fugitive number 36 on its 50 Greatest Shows of All Time list.",
"title": "Acting career"
},
{
"paragraph_id": 6,
"text": "His films include: To Hell and Back, the biography of Audie Murphy, who was the most decorated American soldier of World War II; Hell to Eternity, a 1960 American World War II biopic starring Jeffrey Hunter as a Hispanic boy who fought in the Battle of Saipan and who was raised by Japanese-American foster parents; John Wayne's Vietnam war film The Green Berets; opposite Gregory Peck, in the space story Marooned, in which Janssen played an astronaut sent to rescue three stranded men in space; and The Shoes of the Fisherman, as a television journalist in Rome reporting on the election of a new Pope (Anthony Quinn).",
"title": "Acting career"
},
{
"paragraph_id": 7,
"text": "He also played pilot Harry Walker in the 1973 action movie Birds of Prey. He starred as a Los Angeles police detective trying to clear himself in the killing of an apparently innocent doctor in the 1967 film Warning Shot, which was shot during a break in the spring and summer of 1966 between the third and fourth seasons of The Fugitive.",
"title": "Acting career"
},
{
"paragraph_id": 8,
"text": "Janssen played an alcoholic in the 1977 TV movie A Sensitive, Passionate Man, which co-starred Angie Dickinson, and played an engineer who devises an unbeatable system for blackjack in the 1978 made-for-TV movie Nowhere to Run, co-starring Stefanie Powers and Linda Evans. Janssen's impressively husky voice was used to good effect as the narrator for the TV mini-series Centennial (1978–79); he also appeared in the final episode. And in 1979 he starred in the made-for-TV mini series S.O.S. Titanic as John Jacob Astor, playing opposite Beverly Ross as his wife, Madeleine.",
"title": "Acting career"
},
{
"paragraph_id": 9,
"text": "Though Janssen's scenes were cut from the final release, he also appeared as a journalist in the film Inchon, which he accepted in order to work with Laurence Olivier, who played General Douglas MacArthur. At the time of his death, Janssen had just begun filming a television movie playing the part of Father Damien, the priest who dedicated himself to the leper colony on the island of Molokai, Hawaii. The part was eventually reassigned to actor Ken Howard of the CBS series The White Shadow.",
"title": "Acting career"
},
{
"paragraph_id": 10,
"text": "Janssen was married twice. His first marriage was to model and interior decorator Ellie Graham, whom he married in Las Vegas on August 25, 1958. They divorced in 1968. In 1975, he married actress and model Dani Crayne Greco. They remained married until Janssen's death.",
"title": "Personal life"
},
{
"paragraph_id": 11,
"text": "Janssen was a heavy drinker who smoked up to four packs of cigarettes a day. He died from a sudden heart attack in the early morning of February 13, 1980, at his beachfront home in Malibu, California, at the age of 48. At the time of his death, Janssen was filming the television movie Father Damien. Janssen was buried at the Hillside Memorial Park Cemetery in Culver City, California. A non-denominational funeral was held at the Jewish chapel of the cemetery on February 17. Suzanne Pleshette delivered the eulogy at the request of Janssen's widow. Milton Berle, Johnny Carson, Tommy Gallagher, Richard Harris, Stan Herman, Rod Stewart and Gregory Peck were among Janssen's pallbearers. Honorary pallbearers included Jack Lemmon, George Peppard, James Stewart and Danny Thomas.",
"title": "Death"
},
{
"paragraph_id": 12,
"text": "According to friend and Fugitive co-star Barry Morse, \"David Janssen was well known as one of the hardest working actors in the USA,\" regularly working 12–14 hours a day, and he kept working until his early death.",
"title": "Death"
},
{
"paragraph_id": 13,
"text": "For his contribution to the television industry, David Janssen has a star on the Hollywood Walk of Fame located on the 7700 block of Hollywood Boulevard.",
"title": "Death"
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] | David Janssen was an American film and television actor who is best known for his starring role as Richard Kimble in the television series The Fugitive (1963–1967). Janssen also had the title roles in three other series: Richard Diamond, Private Detective; O'Hara, U.S. Treasury and Harry O. In 1996 TV Guide ranked him number 36 on its 50 Greatest TV Stars of All Time list. | 2001-08-21T02:58:50Z | 2023-11-12T11:52:35Z | [
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8,344 | Docetism | In the history of Christianity, docetism (from the Koinē Greek: δοκεῖν/δόκησις dokeĩn "to seem", dókēsis "apparition, phantom") is the heterodox doctrine that the phenomenon of Jesus, his historical and bodily existence, and above all the human form of Jesus, was mere semblance without any true reality. Broadly it is taken as the belief that Jesus only seemed to be human, and that his human form was an illusion.
The word Δοκηταί Dokētaí ("Illusionists") referring to early groups who denied Jesus's humanity, first occurred in a letter by Bishop Serapion of Antioch (197–203), who discovered the doctrine in the Gospel of Peter, during a pastoral visit to a Christian community using it in Rhosus, and later condemned it as a forgery. It appears to have arisen over theological contentions concerning the meaning, figurative or literal, of a sentence from the Gospel of John: "the Word was made Flesh".
Docetism was unequivocally rejected at the First Council of Nicaea in 325 and is regarded as heretical by the Catholic Church, Eastern Orthodox Church, Coptic Orthodox Church of Alexandria, Armenian Apostolic Church, Ethiopian Orthodox Tewahedo Church, and many Protestant denominations that accept and hold to the statements of these early church councils, such as Reformed Baptists, Reformed Christians, and all Trinitarian Christians.
Docetism is broadly defined as any teaching that claims that Jesus' body was either absent or illusory. The term 'docetic' is rather nebulous. Two varieties were widely known. In one version, as in Marcionism, Christ was so divine that he could not have been human, since God lacked a material body, which therefore could not physically suffer. Jesus only appeared to be a flesh-and-blood man; his body was a phantasm. Other groups who were accused of docetism held that Jesus was a man in the flesh, but Christ was a separate entity who entered Jesus' body in the form of a dove at his baptism, empowered him to perform miracles, and abandoned him upon his death on the cross.
Docetism's origin within Christianity is obscure. Ernst Käsemann controversially defined the Christology of the Gospel of John as "naïve docetism" in 1968. The ensuing debate reached an impasse as awareness grew that the very term "docetism", like "gnosticism", was difficult to define within the religio-historical framework of the debate. It has occasionally been argued that its origins were in heterodox Judaism or Oriental and Grecian philosophies. The alleged connection with Jewish Christianity would have reflected Jewish Christian concerns with the inviolability of (Jewish) monotheism. Docetic opinions seem to have circulated from very early times, 1 John 4:2 appearing explicitly to reject them. Some 1st‑century Christian groups developed docetic interpretations partly as a way to make Christian teachings more acceptable to pagan ways of thinking about divinity.
In his critique of the theology of Clement of Alexandria, Photius in his Myriobiblon held that Clement's views reflected a quasi-docetic view of the nature of Christ, writing that "[Clement] hallucinates that the Word was not incarnate but only seems to be." (ὀνειροπολεῖ καὶ μὴ σαρκωθῆναι τὸν λόγον ἀλλὰ δόξαι.) In Clement's time, some disputes contended over whether Christ assumed the "psychic" flesh of mankind as heirs to Adam, or the "spiritual" flesh of the resurrection. Docetism largely died out during the first millennium AD.
The opponents against whom Ignatius of Antioch inveighs are often taken to be Monophysite docetists. In his letter to the Smyrnaeans, 7:1, written around 110 AD, he writes:
They abstain from the Eucharist and from prayer, because they confess not the Eucharist to be the flesh of our Saviour Jesus Christ, which suffered for our sins, and which the Father, of His goodness, raised up again. They who deny the gift of God are perishing in their disputes.
While these characteristics fit a Monophysite framework, a slight majority of scholars consider that Ignatius was waging a polemic on two distinct fronts, one Jewish, the other docetic; a minority holds that he was concerned with a group that commingled Judaism and docetism. Others, however, doubt that there was actual docetism threatening the churches, arguing that he was merely criticizing Christians who lived Jewishly or that his critical remarks were directed at an Ebionite or Cerinthian possessionist Christology, according to which Christ was a heavenly spirit that temporarily possessed Jesus.
Some commentators have attempted to make a connection between Islam and docetism using the following Quranic verse:
And because of their saying: We slew the Messiah, Jesus son of Mary, Allah's messenger — they slew him not nor crucified him, but it appeared so unto them; and lo! those who disagree concerning it are in doubt thereof; they have no knowledge thereof save pursuit of a conjecture; they slew him not for certain. But Allah took him up unto Himself. Allah was ever Mighty, Wise.
Some scholars theorise that Islam was influenced by Manichaeism (Docetism) in this view. However the general consensus is that Manichaeism was not prevalent in Mecca in the 6th and 7th centuries, when Islam developed, and the influence can therefore not be proven.
Since Arthur Drews published his The Christ Myth (Die Christusmythe) in 1909, occasional connections have been drawn between docetist theories and the modern idea that Christ was a myth. Shailer Mathews called Drews' theory a "modern docetism". Frederick Cornwallis Conybeare thought any connection to be based on a misunderstanding of docetism. The idea recurred in classicist Michael Grant's 1977 review of the evidence for Jesus, who compared modern scepticism about a historical Jesus to the ancient docetic idea that Jesus only seemed to come into the world "in the flesh". Modern supporters of the theory did away with "seeming". | [
{
"paragraph_id": 0,
"text": "In the history of Christianity, docetism (from the Koinē Greek: δοκεῖν/δόκησις dokeĩn \"to seem\", dókēsis \"apparition, phantom\") is the heterodox doctrine that the phenomenon of Jesus, his historical and bodily existence, and above all the human form of Jesus, was mere semblance without any true reality. Broadly it is taken as the belief that Jesus only seemed to be human, and that his human form was an illusion.",
"title": ""
},
{
"paragraph_id": 1,
"text": "The word Δοκηταί Dokētaí (\"Illusionists\") referring to early groups who denied Jesus's humanity, first occurred in a letter by Bishop Serapion of Antioch (197–203), who discovered the doctrine in the Gospel of Peter, during a pastoral visit to a Christian community using it in Rhosus, and later condemned it as a forgery. It appears to have arisen over theological contentions concerning the meaning, figurative or literal, of a sentence from the Gospel of John: \"the Word was made Flesh\".",
"title": ""
},
{
"paragraph_id": 2,
"text": "Docetism was unequivocally rejected at the First Council of Nicaea in 325 and is regarded as heretical by the Catholic Church, Eastern Orthodox Church, Coptic Orthodox Church of Alexandria, Armenian Apostolic Church, Ethiopian Orthodox Tewahedo Church, and many Protestant denominations that accept and hold to the statements of these early church councils, such as Reformed Baptists, Reformed Christians, and all Trinitarian Christians.",
"title": ""
},
{
"paragraph_id": 3,
"text": "Docetism is broadly defined as any teaching that claims that Jesus' body was either absent or illusory. The term 'docetic' is rather nebulous. Two varieties were widely known. In one version, as in Marcionism, Christ was so divine that he could not have been human, since God lacked a material body, which therefore could not physically suffer. Jesus only appeared to be a flesh-and-blood man; his body was a phantasm. Other groups who were accused of docetism held that Jesus was a man in the flesh, but Christ was a separate entity who entered Jesus' body in the form of a dove at his baptism, empowered him to perform miracles, and abandoned him upon his death on the cross.",
"title": "Definitions"
},
{
"paragraph_id": 4,
"text": "Docetism's origin within Christianity is obscure. Ernst Käsemann controversially defined the Christology of the Gospel of John as \"naïve docetism\" in 1968. The ensuing debate reached an impasse as awareness grew that the very term \"docetism\", like \"gnosticism\", was difficult to define within the religio-historical framework of the debate. It has occasionally been argued that its origins were in heterodox Judaism or Oriental and Grecian philosophies. The alleged connection with Jewish Christianity would have reflected Jewish Christian concerns with the inviolability of (Jewish) monotheism. Docetic opinions seem to have circulated from very early times, 1 John 4:2 appearing explicitly to reject them. Some 1st‑century Christian groups developed docetic interpretations partly as a way to make Christian teachings more acceptable to pagan ways of thinking about divinity.",
"title": "Christology and theological implications"
},
{
"paragraph_id": 5,
"text": "In his critique of the theology of Clement of Alexandria, Photius in his Myriobiblon held that Clement's views reflected a quasi-docetic view of the nature of Christ, writing that \"[Clement] hallucinates that the Word was not incarnate but only seems to be.\" (ὀνειροπολεῖ καὶ μὴ σαρκωθῆναι τὸν λόγον ἀλλὰ δόξαι.) In Clement's time, some disputes contended over whether Christ assumed the \"psychic\" flesh of mankind as heirs to Adam, or the \"spiritual\" flesh of the resurrection. Docetism largely died out during the first millennium AD.",
"title": "Christology and theological implications"
},
{
"paragraph_id": 6,
"text": "The opponents against whom Ignatius of Antioch inveighs are often taken to be Monophysite docetists. In his letter to the Smyrnaeans, 7:1, written around 110 AD, he writes:",
"title": "Christology and theological implications"
},
{
"paragraph_id": 7,
"text": "They abstain from the Eucharist and from prayer, because they confess not the Eucharist to be the flesh of our Saviour Jesus Christ, which suffered for our sins, and which the Father, of His goodness, raised up again. They who deny the gift of God are perishing in their disputes.",
"title": "Christology and theological implications"
},
{
"paragraph_id": 8,
"text": "While these characteristics fit a Monophysite framework, a slight majority of scholars consider that Ignatius was waging a polemic on two distinct fronts, one Jewish, the other docetic; a minority holds that he was concerned with a group that commingled Judaism and docetism. Others, however, doubt that there was actual docetism threatening the churches, arguing that he was merely criticizing Christians who lived Jewishly or that his critical remarks were directed at an Ebionite or Cerinthian possessionist Christology, according to which Christ was a heavenly spirit that temporarily possessed Jesus.",
"title": "Christology and theological implications"
},
{
"paragraph_id": 9,
"text": "Some commentators have attempted to make a connection between Islam and docetism using the following Quranic verse:",
"title": "Islam and docetism"
},
{
"paragraph_id": 10,
"text": "And because of their saying: We slew the Messiah, Jesus son of Mary, Allah's messenger — they slew him not nor crucified him, but it appeared so unto them; and lo! those who disagree concerning it are in doubt thereof; they have no knowledge thereof save pursuit of a conjecture; they slew him not for certain. But Allah took him up unto Himself. Allah was ever Mighty, Wise.",
"title": "Islam and docetism"
},
{
"paragraph_id": 11,
"text": "Some scholars theorise that Islam was influenced by Manichaeism (Docetism) in this view. However the general consensus is that Manichaeism was not prevalent in Mecca in the 6th and 7th centuries, when Islam developed, and the influence can therefore not be proven.",
"title": "Islam and docetism"
},
{
"paragraph_id": 12,
"text": "Since Arthur Drews published his The Christ Myth (Die Christusmythe) in 1909, occasional connections have been drawn between docetist theories and the modern idea that Christ was a myth. Shailer Mathews called Drews' theory a \"modern docetism\". Frederick Cornwallis Conybeare thought any connection to be based on a misunderstanding of docetism. The idea recurred in classicist Michael Grant's 1977 review of the evidence for Jesus, who compared modern scepticism about a historical Jesus to the ancient docetic idea that Jesus only seemed to come into the world \"in the flesh\". Modern supporters of the theory did away with \"seeming\".",
"title": "Docetism and Christ myth theory"
}
] | In the history of Christianity, docetism is the heterodox doctrine that the phenomenon of Jesus, his historical and bodily existence, and above all the human form of Jesus, was mere semblance without any true reality. Broadly it is taken as the belief that Jesus only seemed to be human, and that his human form was an illusion. The word Δοκηταί Dokētaí ("Illusionists") referring to early groups who denied Jesus's humanity, first occurred in a letter by Bishop Serapion of Antioch (197–203), who discovered the doctrine in the Gospel of Peter, during a pastoral visit to a Christian community using it in Rhosus, and later condemned it as a forgery. It appears to have arisen over theological contentions concerning the meaning, figurative or literal, of a sentence from the Gospel of John: "the Word was made Flesh". Docetism was unequivocally rejected at the First Council of Nicaea in 325 and is regarded as heretical by the Catholic Church, Eastern Orthodox Church, Coptic Orthodox Church of Alexandria, Armenian Apostolic Church, Ethiopian Orthodox Tewahedo Church, and many Protestant denominations that accept and hold to the statements of these early church councils, such as Reformed Baptists, Reformed Christians, and all Trinitarian Christians. | 2001-11-09T22:22:37Z | 2023-11-04T16:10:43Z | [
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8,347 | Drachma | Drachma may refer to: | [
{
"paragraph_id": 0,
"text": "Drachma may refer to:",
"title": ""
}
] | Drachma may refer to: Ancient drachma, an ancient Greek currency
Modern drachma, a modern Greek currency
Cretan drachma, currency of the Cretan State
Drachma (moth), a moth genus | 2023-06-02T02:54:54Z | [
"Template:Disambiguation"
] | https://en.wikipedia.org/wiki/Drachma |
|
8,349 | Denarius | The denarius (Latin: [deːˈnaːriʊs]; pl.: dēnāriī, Latin: [deːˈnaːriiː]) was the standard Roman silver coin from its introduction in the Second Punic War c. 211 BC to the reign of Gordian III (AD 238–244), when it was gradually replaced by the antoninianus. It continued to be minted in very small quantities, likely for ceremonial purposes, until and through the Tetrarchy (293–313).
The word dēnārius is derived from the Latin dēnī "containing ten", as its value was originally of 10 assēs. The word for "money" descends from it in Italian (denaro), Slovene (denar), Portuguese (dinheiro), and Spanish (dinero). Its name also survives in the dinar currency.
Its symbol is represented in Unicode as 𐆖 (U+10196), a numeral monogram that appeared on the obverse in the Republican period, denoting the 10 asses ("X") to 1 denarius ("I") conversion rate. However it can also be represented as X̶ (capital letter X with combining long stroke overlay).
A predecessor of the denarius was first struck in 269 or 268 BC, five years before the First Punic War, with an average weight of 6.81 grams, or 1⁄48 of a Roman pound. Contact with the Greeks had prompted a need for silver coinage in addition to the bronze currency that the Romans were using at that time. This predecessor of the denarius was a Greek-styled silver coin of didrachm weight, which was struck in Neapolis and other Greek cities in southern Italy. These coins were inscribed with a legend that indicated that they were struck for Rome, but in style they closely resembled their Greek counterparts. They were rarely seen at Rome, to judge from finds and hoards, and were probably used either to buy supplies or pay soldiers.
The first distinctively Roman silver coin appeared around 226 BC. Classical historians have sometimes called these coins "heavy denarii", but they are classified by modern numismatists as quadrigati, a term which survives in one or two ancient texts and is derived from the quadriga, or four-horse chariot, on the reverse. This, with a two-horse chariot or biga which was used as a reverse type for some early denarii, was the prototype for the most common designs used on Roman silver coins for a number of years.
Rome overhauled its coinage shortly before 211 BC, and introduced the denarius alongside a short-lived denomination called the victoriatus. The denarius contained an average 4.5 grams, or 1⁄72 of a Roman pound, of silver, and was at first tariffed at ten asses, hence its name, which means 'tenner'. It formed the backbone of Roman currency throughout the Roman Republic and the early Empire.
The denarius began to undergo slow debasement toward the end of the republican period. Under the rule of Augustus (27 BC – AD 14) its weight fell to 3.9 grams (a theoretical weight of 1⁄84 of a Roman pound). It remained at nearly this weight until the time of Nero (AD 37–68), when it was reduced to 1⁄96 of a pound, or 3.4 grams. Debasement of the coin's silver content continued after Nero. Later Roman emperors also reduced its weight to 3 grams around the late 3rd century.
The value at its introduction was 10 asses, giving the denarius its name, which translates as "containing ten". In about 141 BC, it was re-tariffed at 16 asses, to reflect the decrease in weight of the as. The denarius continued to be the main coin of the Roman Empire until it was replaced by the antoninianus in the early 3rd century AD. The coin was last issued, in bronze, under Aurelian between AD 270 and 275, and in the first years of the reign of Diocletian.
1 gold aureus = 2 gold quinarii = 25 silver denarii = 50 silver quinarii = 100 bronze sestertii = 200 bronze dupondii = 400 copper asses = 800 copper semisses = 1,600 copper quadrantes
It is difficult to give even rough comparative values for money from before the 20th century, as the range of products and services available for purchase was so different. During the republic (509 BC–27 BC), a legionary earned 112.5 denarii per year (0.3 denarii per day). Under Julius Caesar, this was doubled to 225 denarii/yr, with soldiers having to pay for their own food and arms, while in the reign of Augustus a Centurion received at least 3,750 denarii per year, and for the highest rank, 15,000 denarii.
By the late Roman Republic and early Roman Empire (c. 27 BC), a common soldier or unskilled laborer would be paid 1 denarius/day (with no tax deductions), around 300% inflation compared to the early period. Using the cost of bread as a baseline, this pay equates to around US$20 in 2013 terms. Expressed in terms of the price of silver, and assuming 0.999 purity, a 1⁄10 troy ounce denarius had a precious metal value of around US$2.60 in 2021.
At the height of the Roman Empire a sextarius (546ml or about 2 1/4 cups) of ordinary wine cost roughly one dupondius (1⁄8 of a denarius); after Diocletian's Edict on Maximum Prices was issued in AD 301, the same item cost 8 debased common denarii – 6300% inflation.
Silver content plummeted across the lifespan of the denarius. Under the Roman Empire (after Nero) the denarius contained approximately 50 grains, 3.24 grams, or 1⁄10 (0.105ozt) troy ounce. The fineness of the silver content varied with political and economic circumstances. From a purity of greater than 90% silver in the 1st century AD, the denarius fell to under 60% purity by AD 200, and plummeted to 5% purity by AD 300. By the reign of Gallienus, the antoninianus was a copper coin with a thin silver wash.
In the final years of the 1st century BC Tincomarus, a local ruler in southern Britain, started issuing coins that appear to have been made from melted down denarii. The coins of Eppillus, issued around Calleva Atrebatum around the same time, appear to have derived design elements from various denarii such as those of Augustus and M. Volteius.
Even after the denarius was no longer regularly issued, it continued to be used as a unit of account, and the name was applied to later Roman coins in a way that is not understood. The Arabs who conquered large parts of the land that once belonged to the Eastern Roman Empire issued their own gold dinar. The lasting legacy of the denarius can be seen in the use of "d" as the abbreviation for the British penny until 1971. It also survived in France as the name of a coin, the denier. The denarius also survives in the common Arabic name for a currency unit, the dinar used from pre-Islamic times, and still used in several modern Arab nations. The major currency unit in former Principality of Serbia, Kingdom of Serbia and former Yugoslavia was dinar, and it is still used in present-day Serbia. The Macedonian currency denar is also derived from the Roman denarius. The Italian word denaro, the Spanish word dinero, the Portuguese word dinheiro, and the Slovene word denar, all meaning money, are also derived from Latin denarius. The pre-decimal currency of the United Kingdom until 1970 of pounds, shillings and pence was abbreviated as lsd, with "d" referring to denarius and standing for penny.
In the New Testament, the gospels refer to the denarius as a day's wage for a common laborer (Matthew 20:2, John 12:5). In the Book of Revelation, during the Third Seal: Black Horse, a choinix ("quart") of wheat and three quarts of barley were each valued at one denarius. Bible scholar Robert H. Mounce says the price of the wheat and barley as described in the vision appears to be ten to twelve times their normal cost in ancient times. Revelation thus describes a condition where basic goods are sold at greatly inflated prices. Thus, the black horse rider depicts times of deep scarcity or famine, but not of starvation. Apparently, a choinix of wheat was the daily ration of one adult. Thus, in the conditions pictured by Revelation 6, the normal income for a working-class family would buy enough food for only one person. The less costly barley would feed three people for one day's wages.
The denarius is also mentioned in the Parable of the Unforgiving Servant & in Parable of the Good Samaritan (Luke 10:25–37). The Render unto Caesar passage in Matthew 22:15–22 and Mark 12:13–17 uses the word (δηνάριον) to describe the coin held up by Jesus, translated in the King James Bible as "tribute penny". It is commonly thought to be a denarius with the head of Tiberius. | [
{
"paragraph_id": 0,
"text": "The denarius (Latin: [deːˈnaːriʊs]; pl.: dēnāriī, Latin: [deːˈnaːriiː]) was the standard Roman silver coin from its introduction in the Second Punic War c. 211 BC to the reign of Gordian III (AD 238–244), when it was gradually replaced by the antoninianus. It continued to be minted in very small quantities, likely for ceremonial purposes, until and through the Tetrarchy (293–313).",
"title": ""
},
{
"paragraph_id": 1,
"text": "The word dēnārius is derived from the Latin dēnī \"containing ten\", as its value was originally of 10 assēs. The word for \"money\" descends from it in Italian (denaro), Slovene (denar), Portuguese (dinheiro), and Spanish (dinero). Its name also survives in the dinar currency.",
"title": ""
},
{
"paragraph_id": 2,
"text": "Its symbol is represented in Unicode as 𐆖 (U+10196), a numeral monogram that appeared on the obverse in the Republican period, denoting the 10 asses (\"X\") to 1 denarius (\"I\") conversion rate. However it can also be represented as X̶ (capital letter X with combining long stroke overlay).",
"title": ""
},
{
"paragraph_id": 3,
"text": "A predecessor of the denarius was first struck in 269 or 268 BC, five years before the First Punic War, with an average weight of 6.81 grams, or 1⁄48 of a Roman pound. Contact with the Greeks had prompted a need for silver coinage in addition to the bronze currency that the Romans were using at that time. This predecessor of the denarius was a Greek-styled silver coin of didrachm weight, which was struck in Neapolis and other Greek cities in southern Italy. These coins were inscribed with a legend that indicated that they were struck for Rome, but in style they closely resembled their Greek counterparts. They were rarely seen at Rome, to judge from finds and hoards, and were probably used either to buy supplies or pay soldiers.",
"title": "History"
},
{
"paragraph_id": 4,
"text": "The first distinctively Roman silver coin appeared around 226 BC. Classical historians have sometimes called these coins \"heavy denarii\", but they are classified by modern numismatists as quadrigati, a term which survives in one or two ancient texts and is derived from the quadriga, or four-horse chariot, on the reverse. This, with a two-horse chariot or biga which was used as a reverse type for some early denarii, was the prototype for the most common designs used on Roman silver coins for a number of years.",
"title": "History"
},
{
"paragraph_id": 5,
"text": "Rome overhauled its coinage shortly before 211 BC, and introduced the denarius alongside a short-lived denomination called the victoriatus. The denarius contained an average 4.5 grams, or 1⁄72 of a Roman pound, of silver, and was at first tariffed at ten asses, hence its name, which means 'tenner'. It formed the backbone of Roman currency throughout the Roman Republic and the early Empire.",
"title": "History"
},
{
"paragraph_id": 6,
"text": "The denarius began to undergo slow debasement toward the end of the republican period. Under the rule of Augustus (27 BC – AD 14) its weight fell to 3.9 grams (a theoretical weight of 1⁄84 of a Roman pound). It remained at nearly this weight until the time of Nero (AD 37–68), when it was reduced to 1⁄96 of a pound, or 3.4 grams. Debasement of the coin's silver content continued after Nero. Later Roman emperors also reduced its weight to 3 grams around the late 3rd century.",
"title": "History"
},
{
"paragraph_id": 7,
"text": "The value at its introduction was 10 asses, giving the denarius its name, which translates as \"containing ten\". In about 141 BC, it was re-tariffed at 16 asses, to reflect the decrease in weight of the as. The denarius continued to be the main coin of the Roman Empire until it was replaced by the antoninianus in the early 3rd century AD. The coin was last issued, in bronze, under Aurelian between AD 270 and 275, and in the first years of the reign of Diocletian.",
"title": "History"
},
{
"paragraph_id": 8,
"text": "1 gold aureus = 2 gold quinarii = 25 silver denarii = 50 silver quinarii = 100 bronze sestertii = 200 bronze dupondii = 400 copper asses = 800 copper semisses = 1,600 copper quadrantes",
"title": "Value, comparisons and silver content"
},
{
"paragraph_id": 9,
"text": "It is difficult to give even rough comparative values for money from before the 20th century, as the range of products and services available for purchase was so different. During the republic (509 BC–27 BC), a legionary earned 112.5 denarii per year (0.3 denarii per day). Under Julius Caesar, this was doubled to 225 denarii/yr, with soldiers having to pay for their own food and arms, while in the reign of Augustus a Centurion received at least 3,750 denarii per year, and for the highest rank, 15,000 denarii.",
"title": "Value, comparisons and silver content"
},
{
"paragraph_id": 10,
"text": "By the late Roman Republic and early Roman Empire (c. 27 BC), a common soldier or unskilled laborer would be paid 1 denarius/day (with no tax deductions), around 300% inflation compared to the early period. Using the cost of bread as a baseline, this pay equates to around US$20 in 2013 terms. Expressed in terms of the price of silver, and assuming 0.999 purity, a 1⁄10 troy ounce denarius had a precious metal value of around US$2.60 in 2021.",
"title": "Value, comparisons and silver content"
},
{
"paragraph_id": 11,
"text": "At the height of the Roman Empire a sextarius (546ml or about 2 1/4 cups) of ordinary wine cost roughly one dupondius (1⁄8 of a denarius); after Diocletian's Edict on Maximum Prices was issued in AD 301, the same item cost 8 debased common denarii – 6300% inflation.",
"title": "Value, comparisons and silver content"
},
{
"paragraph_id": 12,
"text": "Silver content plummeted across the lifespan of the denarius. Under the Roman Empire (after Nero) the denarius contained approximately 50 grains, 3.24 grams, or 1⁄10 (0.105ozt) troy ounce. The fineness of the silver content varied with political and economic circumstances. From a purity of greater than 90% silver in the 1st century AD, the denarius fell to under 60% purity by AD 200, and plummeted to 5% purity by AD 300. By the reign of Gallienus, the antoninianus was a copper coin with a thin silver wash.",
"title": "Value, comparisons and silver content"
},
{
"paragraph_id": 13,
"text": "In the final years of the 1st century BC Tincomarus, a local ruler in southern Britain, started issuing coins that appear to have been made from melted down denarii. The coins of Eppillus, issued around Calleva Atrebatum around the same time, appear to have derived design elements from various denarii such as those of Augustus and M. Volteius.",
"title": "Influence"
},
{
"paragraph_id": 14,
"text": "Even after the denarius was no longer regularly issued, it continued to be used as a unit of account, and the name was applied to later Roman coins in a way that is not understood. The Arabs who conquered large parts of the land that once belonged to the Eastern Roman Empire issued their own gold dinar. The lasting legacy of the denarius can be seen in the use of \"d\" as the abbreviation for the British penny until 1971. It also survived in France as the name of a coin, the denier. The denarius also survives in the common Arabic name for a currency unit, the dinar used from pre-Islamic times, and still used in several modern Arab nations. The major currency unit in former Principality of Serbia, Kingdom of Serbia and former Yugoslavia was dinar, and it is still used in present-day Serbia. The Macedonian currency denar is also derived from the Roman denarius. The Italian word denaro, the Spanish word dinero, the Portuguese word dinheiro, and the Slovene word denar, all meaning money, are also derived from Latin denarius. The pre-decimal currency of the United Kingdom until 1970 of pounds, shillings and pence was abbreviated as lsd, with \"d\" referring to denarius and standing for penny.",
"title": "Influence"
},
{
"paragraph_id": 15,
"text": "In the New Testament, the gospels refer to the denarius as a day's wage for a common laborer (Matthew 20:2, John 12:5). In the Book of Revelation, during the Third Seal: Black Horse, a choinix (\"quart\") of wheat and three quarts of barley were each valued at one denarius. Bible scholar Robert H. Mounce says the price of the wheat and barley as described in the vision appears to be ten to twelve times their normal cost in ancient times. Revelation thus describes a condition where basic goods are sold at greatly inflated prices. Thus, the black horse rider depicts times of deep scarcity or famine, but not of starvation. Apparently, a choinix of wheat was the daily ration of one adult. Thus, in the conditions pictured by Revelation 6, the normal income for a working-class family would buy enough food for only one person. The less costly barley would feed three people for one day's wages.",
"title": "Use in the Bible"
},
{
"paragraph_id": 16,
"text": "The denarius is also mentioned in the Parable of the Unforgiving Servant & in Parable of the Good Samaritan (Luke 10:25–37). The Render unto Caesar passage in Matthew 22:15–22 and Mark 12:13–17 uses the word (δηνάριον) to describe the coin held up by Jesus, translated in the King James Bible as \"tribute penny\". It is commonly thought to be a denarius with the head of Tiberius.",
"title": "Use in the Bible"
}
] | The denarius was the standard Roman silver coin from its introduction in the Second Punic War c. 211 BC to the reign of Gordian III, when it was gradually replaced by the antoninianus. It continued to be minted in very small quantities, likely for ceremonial purposes, until and through the Tetrarchy (293–313). The word dēnārius is derived from the Latin dēnī "containing ten", as its value was originally of 10 assēs. The word for "money" descends from it in Italian (denaro), Slovene (denar), Portuguese (dinheiro), and Spanish (dinero). Its name also survives in the dinar currency. Its symbol is represented in Unicode as 𐆖 (U+10196), a numeral monogram that appeared on the obverse in the Republican period, denoting the 10 asses ("X") to 1 denarius ("I") conversion rate. However it can also be represented as X̶. | 2001-08-21T19:34:55Z | 2023-12-29T11:37:49Z | [
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8,350 | Della Rovere | The House of Della Rovere (pronounced [della ˈroːvere]; literally "of the oak tree") was a powerful Italian noble family. It had humble origins in Savona, in Liguria, and acquired power and influence through nepotism and ambitious marriages arranged by two Della Rovere popes: Francesco Della Rovere, who ruled as Sixtus IV from 1471 to 1484) and his nephew Giuliano, who became Julius II in 1503. Sixtus IV built the Sistine Chapel, which is named for him. Julius II was patron to Michelangelo, Raphael and many other Renaissance artists and started the modern rebuilt of St. Peter's Basilica. Also the Basilica of San Pietro in Vincoli in Rome was the family church of the Della Rovere. Members of the family were influential in the Church of Rome, and as dukes of Urbino, dukes of Sora and lords of Senigallia; the title of Urbino was extinguished with the death of Francesco Maria II in 1631, and the family died out with the death of his granddaughter Vittoria, Grand Duchess of Tuscany.
Francesco Della Rovere was born into a poor family in Liguria in north-west Italy in 1414, the son of Leonardo della Rovere of Savona. A Franciscan who became Minister General of his order, then cardinal, he had a reptation for unworldliness until he was elected pope in 1471. As Sixtus IV he was both wealthy and powerful, and at once set about giving power and wealth to his nephews of the Della Rovere and Riario families. Within months of his election, he had made Giuliano della Rovere (the future pope Julius II) and Pietro Riario both cardinals and bishops; four other nephews were also made cardinals. He made Giovanni Della Rovere, who was not a priest, prefect of Rome, and arranged for him to marry into the da Montefeltro family, dukes of Urbino. Sixtus claimed descent from a noble Della Rovere family, the counts of Vinovo in Piemonte, and adopted their coat-of-arms.
Guidobaldo da Montefeltro adopted Francesco Maria I della Rovere, his sister's child and nephew of Pope Julius II. Guidobaldo I, who was heirless, called Francesco Maria at his court, and named him as heir of the Duchy of Urbino in 1504, this through the intercession of Julius II. In 1508, Francesco Maria inherited the duchy thereby starting the line of Rovere Dukes of Urbino. That dynasty ended in 1626 when Pope Urban VIII incorporated Urbino into the papal dominions. As compensation to the last sovereign duke, the title only could be continued by Francesco Maria II, and after his death by his heir, Federico Ubaldo.
Vittoria, last descendant of the della Rovere family (she was the only child of Federico Ubaldo), married Ferdinando II de' Medici, Grand Duke of Tuscany. They had two children: Cosimo III, Tuscany's longest reigning monarch, and Francesco Maria de' Medici, a prince of the Church.
Among the many people who did not belong to this family, but bore the same name, are:
and various artists, including: | [
{
"paragraph_id": 0,
"text": "The House of Della Rovere (pronounced [della ˈroːvere]; literally \"of the oak tree\") was a powerful Italian noble family. It had humble origins in Savona, in Liguria, and acquired power and influence through nepotism and ambitious marriages arranged by two Della Rovere popes: Francesco Della Rovere, who ruled as Sixtus IV from 1471 to 1484) and his nephew Giuliano, who became Julius II in 1503. Sixtus IV built the Sistine Chapel, which is named for him. Julius II was patron to Michelangelo, Raphael and many other Renaissance artists and started the modern rebuilt of St. Peter's Basilica. Also the Basilica of San Pietro in Vincoli in Rome was the family church of the Della Rovere. Members of the family were influential in the Church of Rome, and as dukes of Urbino, dukes of Sora and lords of Senigallia; the title of Urbino was extinguished with the death of Francesco Maria II in 1631, and the family died out with the death of his granddaughter Vittoria, Grand Duchess of Tuscany.",
"title": ""
},
{
"paragraph_id": 1,
"text": "Francesco Della Rovere was born into a poor family in Liguria in north-west Italy in 1414, the son of Leonardo della Rovere of Savona. A Franciscan who became Minister General of his order, then cardinal, he had a reptation for unworldliness until he was elected pope in 1471. As Sixtus IV he was both wealthy and powerful, and at once set about giving power and wealth to his nephews of the Della Rovere and Riario families. Within months of his election, he had made Giuliano della Rovere (the future pope Julius II) and Pietro Riario both cardinals and bishops; four other nephews were also made cardinals. He made Giovanni Della Rovere, who was not a priest, prefect of Rome, and arranged for him to marry into the da Montefeltro family, dukes of Urbino. Sixtus claimed descent from a noble Della Rovere family, the counts of Vinovo in Piemonte, and adopted their coat-of-arms.",
"title": "History"
},
{
"paragraph_id": 2,
"text": "Guidobaldo da Montefeltro adopted Francesco Maria I della Rovere, his sister's child and nephew of Pope Julius II. Guidobaldo I, who was heirless, called Francesco Maria at his court, and named him as heir of the Duchy of Urbino in 1504, this through the intercession of Julius II. In 1508, Francesco Maria inherited the duchy thereby starting the line of Rovere Dukes of Urbino. That dynasty ended in 1626 when Pope Urban VIII incorporated Urbino into the papal dominions. As compensation to the last sovereign duke, the title only could be continued by Francesco Maria II, and after his death by his heir, Federico Ubaldo.",
"title": "History"
},
{
"paragraph_id": 3,
"text": "Vittoria, last descendant of the della Rovere family (she was the only child of Federico Ubaldo), married Ferdinando II de' Medici, Grand Duke of Tuscany. They had two children: Cosimo III, Tuscany's longest reigning monarch, and Francesco Maria de' Medici, a prince of the Church.",
"title": "History"
},
{
"paragraph_id": 4,
"text": "Among the many people who did not belong to this family, but bore the same name, are:",
"title": "Other people with the same surname"
},
{
"paragraph_id": 5,
"text": "and various artists, including:",
"title": "Other people with the same surname"
}
] | The House of Della Rovere was a powerful Italian noble family. It had humble origins in Savona, in Liguria, and acquired power and influence through nepotism and ambitious marriages arranged by two Della Rovere popes: Francesco Della Rovere, who ruled as Sixtus IV from 1471 to 1484) and his nephew Giuliano, who became Julius II in 1503. Sixtus IV built the Sistine Chapel, which is named for him. Julius II was patron to Michelangelo, Raphael and many other Renaissance artists and started the modern rebuilt of St. Peter's Basilica. Also the Basilica of San Pietro in Vincoli in Rome was the family church of the Della Rovere. Members of the family were influential in the Church of Rome, and as dukes of Urbino, dukes of Sora and lords of Senigallia; the title of Urbino was extinguished with the death of Francesco Maria II in 1631, and the family died out with the death of his granddaughter Vittoria, Grand Duchess of Tuscany. | 2002-02-25T15:51:15Z | 2023-12-27T12:00:07Z | [
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8,351 | David Mamet | David Alan Mamet (/ˈmæmɪt/; born November 30, 1947) is an American playwright, filmmaker, and author. He won a Pulitzer Prize and received Tony nominations for his plays Glengarry Glen Ross (1984) and Speed-the-Plow (1988). He first gained critical acclaim for a trio of off-Broadway 1970s plays: The Duck Variations, Sexual Perversity in Chicago, and American Buffalo. His plays Race and The Penitent, respectively, opened on Broadway in 2009 and previewed off-Broadway in 2017.
Feature films that Mamet both wrote and directed include House of Games (1987), Homicide (1991), The Spanish Prisoner (1997), and his biggest commercial success, Heist (2001). His screenwriting credits include The Postman Always Rings Twice (1981), The Verdict (1982), The Untouchables (1987), Hoffa (1992), Wag the Dog (1997), and Hannibal (2001). Mamet himself wrote the screenplay for the 1992 adaptation of Glengarry Glen Ross, and wrote and directed the 1994 adaptation of his play Oleanna (1992). He created and produced the CBS series The Unit (2006–2009).
Mamet's books include: On Directing Film (1991), a commentary and dialogue about film-making; The Old Religion (1997), a novel about the lynching of Leo Frank; Five Cities of Refuge: Weekly Reflections on Genesis, Exodus, Leviticus, Numbers and Deuteronomy (2004), a Torah commentary with Rabbi Lawrence Kushner; The Wicked Son (2006), a study of Jewish self-hatred and antisemitism; Bambi vs. Godzilla, a commentary on the movie business; The Secret Knowledge: On the Dismantling of American Culture (2011), a commentary on cultural and political issues; and Three War Stories (2013), a trio of novellas about the physical and psychological effects of war.
Mamet was born in 1947 in Chicago to Lenore June (née Silver), a teacher, and Bernard Morris Mamet, a labor attorney. He is Jewish. His paternal grandparents were Polish Jews. Mamet has said his parents were communists and described himself as a red diaper baby. One of his earliest jobs was as a busboy at Chicago's London House and The Second City. He also worked as an actor, editor for Oui magazine and as a cab-driver. He was educated at the progressive Francis W. Parker School and at Goddard College in Plainfield, Vermont. At the Chicago Public Library Foundation 20th anniversary fundraiser in 2006, though, Mamet announced "My alma mater is the Chicago Public Library. I got what little educational foundation I got in the third-floor reading room, under the tutelage of a Coca-Cola sign".
After a move to Chicago's North Side, Mamet encountered theater director Robert Sickinger, and began to work occasionally at Sickinger's Hull House Theatre. This represented the beginning of Mamet's lifelong involvement with the theater.
Mamet is a founding member of the Atlantic Theater Company; he first gained acclaim for a trio of off-Broadway plays in 1976, The Duck Variations, Sexual Perversity in Chicago, and American Buffalo. He was awarded the Pulitzer Prize in 1984 for Glengarry Glen Ross, which received its first Broadway revival in the summer of 2005. His play Race, which opened on Broadway on December 6, 2009, and featured James Spader, David Alan Grier, Kerry Washington, and Richard Thomas in the cast, received mixed reviews. His play The Anarchist, starring Patti LuPone and Debra Winger, in her Broadway debut, opened on Broadway on November 13, 2012, in previews and was scheduled to close on December 16, 2012. His 2017 play The Penitent previewed off-Broadway on February 8, 2017.
In 2002, Mamet was inducted into the American Theater Hall of Fame. Mamet later received the PEN/Laura Pels Theater Award for Grand Master of American Theater in 2010.
In 2017, Mamet released an online class for writers entitled David Mamet teaches dramatic writing.
In 2019 Mamet returned to the London West End with a new play, Bitter Wheat, at the Garrick Theatre, starring John Malkovich.
In 2023 it was announced Mamet was writing a new play entitled, Henry Johnson. The production is announced to debut in Los Angeles starring Shia LaBeouf.
Mamet's first film work was as a screenwriter, later directing his own scripts.
According to Joe Mantegna, Mamet worked as a script doctor for the 1978 film Towing.
Mamet's first produced screenplay was the 1981 production of The Postman Always Rings Twice, based on James M. Cain's novel. He received an Academy Award nomination one year later for the 1982 legal drama, The Verdict. He also wrote the screenplays for The Untouchables (1987), Hoffa (1992), The Edge (1997), Wag the Dog (1997), Ronin (1998), and Hannibal (2001). He received a second Academy Award nomination for Wag the Dog.
In 1987, Mamet made his film directing debut with his screenplay House of Games, which won Best Screenplay awards at the 1987 Venice Film Festival and the Film of the Year in 1989 from the London Film Critics' Circle Awards. The film starred his then-wife, Lindsay Crouse, and many longtime stage associates and friends, including fellow Goddard College graduates. Mamet was quoted as saying, "It was my first film as a director and I needed support, so I stacked the deck." After House of Games, Mamet later wrote and directed two more films focusing on the world of con artists, The Spanish Prisoner (1997) and Heist (2001). Among those films, Heist enjoyed the biggest commercial success.
Other films that Mamet both wrote and directed include: Things Change (1988), Homicide (1991) (nominated for the Palme d'Or at 1991 Cannes Film Festival and won a "Screenwriter of the Year" award for Mamet from the London Film Critics' Circle Awards), Oleanna (1994), The Winslow Boy (1999), State and Main (2000), Spartan (2004), Redbelt (2008), and the 2013 bio-pic TV movie Phil Spector.
A feature-length film, a thriller titled Blackbird, was intended for release in 2015, but is still in development.
When Mamet adapted his play for the 1992 film Glengarry Glen Ross, he wrote an additional part (including the monologue "Coffee's for closers") for Alec Baldwin.
Mamet continues to work with an informal repertory company for his films, including Crouse, William H. Macy, Joe Mantegna, and Rebecca Pidgeon, as well as the aforementioned school friends.
Mamet rewrote the script for Ronin under the pseudonym "Richard Weisz" and turned in an early version of a script for Malcolm X which was rejected by director Spike Lee. Mamet also wrote an unproduced biopic script about Roscoe Arbuckle with Chris Farley intended to portray him. In 2000, Mamet directed a film version of Catastrophe, a one-act play by Samuel Beckett featuring Harold Pinter and John Gielgud (in his final screen performance). In 2008, he wrote and directed the mixed martial arts movie Redbelt, about a martial arts instructor tricked into fighting in a professional bout.
In On Directing Film, Mamet advocates for a method of storytelling based on Eisenstein's montage theory, stating that the story should be told through the juxtaposition of uninflected images. This method relies heavily on the cut between scenes, and Mamet urges directors to eliminate as much narration as possible. Mamet asserts that directors should focus on getting the point of a scene across, rather than simply following a protagonist, or adding visually beautiful or intriguing shots. Films should create order from disorder in search of the objective.
In 2023, reports emerged that Mamet would direct and co-write a new film titled Assassination, his first film since 2008. The film will center around the Chicago Mob ordering the assassination of John F. Kennedy, and will star Viggo Mortensen, Shia LaBeouf, Courtney Love, Al Pacino, and John Travolta. The film's production is scheduled to start in September 2023.
Mamet published the essay collection Writing in Restaurants in 1986, followed by the poetry collection The Hero Pony in 1990. He has also published a series of short plays, monologues and four novels, The Village (1994), The Old Religion (1997), Wilson: A Consideration of the Sources (2000), and Chicago (2018). He has written several non-fiction texts, and children's stories, including True and False: Heresy and Common Sense for the Actor (1997). In 2004 he published a lauded version of the classical Faust story, Faustus, however, when the play was staged in San Francisco during the spring of 2004, it was not well received by critics. On May 1, 2010, Mamet released a graphic novel The Trials of Roderick Spode (The Human Ant).
Mamet detailed his conversion from modern liberalism to "a reformed liberal" in The Secret Knowledge: On the Dismantling of American Culture in 2011. Mamet published Three War Stories, a collection of novellas, in 2013 ; the novel The Diary of a Porn Star by Priscilla Wriston-Ranger: As Told to David Mamet With an Afterword by Mr. Mamet in 2019; and the political commentary Recessional: The Death of Free Speech and the Cost of a Free Lunch in 2022.
Mamet wrote one episode of Hill Street Blues, "A Wasted Weekend", that aired in 1987. His then-wife, Lindsay Crouse, appeared in numerous episodes (including that one) as Officer McBride. Mamet is also the creator, producer and frequent writer of the television series The Unit, where he wrote a well-circulated memo to the writing staff. He directed a third-season episode of The Shield with Shawn Ryan. In 2007, Mamet directed two television commercials for Ford Motor Company. The two 30-second ads featured the Ford Edge and were filmed in Mamet's signature style of fast-paced dialogue and clear, simple imagery. Mamet's sister, Lynn, is a producer and writer for television shows, such as The Unit and Law & Order.
Mamet has contributed several dramas to BBC Radio through Jarvis & Ayres Productions, including an adaptation of Glengarry Glen Ross for BBC Radio 3 and new dramas for BBC Radio 4. The comedy Keep Your Pantheon (or On the Whole I'd Rather Be in Mesopotamia) was aired in 2007. The Christopher Boy's Communion was another Jarvis & Ayres production, first broadcast on BBC Radio 4 on March 8, 2021.
The papers of David Mamet were sold to the Harry Ransom Center at the University of Texas at Austin in 2007 and first opened for research in 2009. The growing collection consists mainly of manuscripts and related production materials for most of his plays, films, and other writings, but also includes his personal journals from 1966 to 2005. In 2015, the Ransom Center secured a second major addition to Mamet's papers, including more recent works. Additional materials relating to Mamet and his career can be found in the Ransom Center's collections of Robert De Niro, Mel Gussow, Tom Stoppard, Sam Shepard, Paul Schrader, Don DeLillo, and John Russell Brown.
Mamet's style of writing dialogue, marked by a cynical, street-smart edge, has come to be called Mamet speak. Mamet himself has criticized his (and other writers') tendency to write "pretty" at the expense of sound, logical plots. When asked how he developed his style for writing dialogue, Mamet said, "In my family, in the days prior to television, we liked to while away the evenings by making ourselves miserable, based solely on our ability to speak the language viciously. That's probably where my ability was honed."
Mamet's plays have frequently sparked debate and controversy. Following a 1992 staging of Oleanna, a play in which a college student accuses her professor of trying to rape her, a critic reported that the play divided the audience by gender and recounted that "couples emerged screaming at each other".
In his 2014 book David Mamet and Male Friendship, Arthur Holmberg examined Mamet's portrayal of male friendships, especially focusing on the contradictions and ambiguities of male bonding as dramatized in Mamet's plays and films.
Mamet and actress Lindsay Crouse married in 1977 and divorced in 1990. The couple have two children. Mamet has been married to actress and singer-songwriter Rebecca Pidgeon since 1991, and they have two children. Mamet and Pidgeon live in Santa Monica, California.
Mamet is a Reform Jew and strongly pro-Israel.
In 2005, Mamet became a contributing blogger for The Huffington Post, drawing satirical cartoons with themes including political strife in Israel. In a 2008 essay at The Village Voice titled "Why I Am No Longer a 'Brain-Dead Liberal'" he discussed how his political views had shifted from liberalism to conservatism. In interviews, Mamet has highlighted his agreement with free market theorists such as Friedrich Hayek, the historian Paul Johnson, and economist Thomas Sowell, whom Mamet called "one of our greatest minds". In 2022, Mamet declined to explicitly label himself a Republican, but described himself as a conservative who "would like to conserve those things I grew up with: the love of family, the love of the country, love of service, love of God, love of community".
During promotion of a book, Mamet said British people had "a taint of anti-semitism," claiming they "want to give [Israel] away to some people whose claim is rather dubious." In the same interview, Mamet went on to say that "there are famous dramatists and novelists [in the UK] whose works are full of anti-Semitic filth." He refused to give examples because of British libel laws (the interview was conducted in New York City for the Financial Times). He is known for his pro-Israel positions; in his book The Secret Knowledge he claimed that "Israelis would like to live in peace within their borders; the Arabs would like to kill them all."
Mamet endorsed Republican Mitt Romney for president in 2012, and wrote an article for The Jewish Journal of Greater Los Angeles imploring fellow Jewish Americans to vote for Romney.
In an essay for Newsweek, published on January 29, 2013, Mamet argued against gun control laws: "It was intended to guard us against this inevitable decay of government that the Constitution was written. Its purpose was and is not to enthrone a Government superior to an imperfect and confused electorate, but to protect us from such a government."
Mamet has described the NFL anthem protests as "absolutely fucking despicable". In a 2020 interview, he described Donald Trump as a "great president" and supported his re-election. After Trump lost the election, Mamet appeared to endorse claims that the election had been illegitimate in his 2022 book Recessional: The Death of Free Speech and the Cost of a Free Lunch, though shortly after its publication, he said he "misspoke" on the subject.
In 2022, Mamet made comments in support of Florida's Parental Rights in Education Act, called the "Don't Say Gay" bill by its critics, which restricts what public school teachers in Florida can discuss with children in kindergarten through third grade about sexual orientation and gender identity. In an interview with Fox News, Mamet claimed that the law was necessary because teachers "are abusing [children] mentally and using sex to do so", further alleging that "teachers are inclined, particularly men because men are predators, to pedophilia".
Films
Short films
Television
Acting roles
Unrealized projects | [
{
"paragraph_id": 0,
"text": "David Alan Mamet (/ˈmæmɪt/; born November 30, 1947) is an American playwright, filmmaker, and author. He won a Pulitzer Prize and received Tony nominations for his plays Glengarry Glen Ross (1984) and Speed-the-Plow (1988). He first gained critical acclaim for a trio of off-Broadway 1970s plays: The Duck Variations, Sexual Perversity in Chicago, and American Buffalo. His plays Race and The Penitent, respectively, opened on Broadway in 2009 and previewed off-Broadway in 2017.",
"title": ""
},
{
"paragraph_id": 1,
"text": "Feature films that Mamet both wrote and directed include House of Games (1987), Homicide (1991), The Spanish Prisoner (1997), and his biggest commercial success, Heist (2001). His screenwriting credits include The Postman Always Rings Twice (1981), The Verdict (1982), The Untouchables (1987), Hoffa (1992), Wag the Dog (1997), and Hannibal (2001). Mamet himself wrote the screenplay for the 1992 adaptation of Glengarry Glen Ross, and wrote and directed the 1994 adaptation of his play Oleanna (1992). He created and produced the CBS series The Unit (2006–2009).",
"title": ""
},
{
"paragraph_id": 2,
"text": "Mamet's books include: On Directing Film (1991), a commentary and dialogue about film-making; The Old Religion (1997), a novel about the lynching of Leo Frank; Five Cities of Refuge: Weekly Reflections on Genesis, Exodus, Leviticus, Numbers and Deuteronomy (2004), a Torah commentary with Rabbi Lawrence Kushner; The Wicked Son (2006), a study of Jewish self-hatred and antisemitism; Bambi vs. Godzilla, a commentary on the movie business; The Secret Knowledge: On the Dismantling of American Culture (2011), a commentary on cultural and political issues; and Three War Stories (2013), a trio of novellas about the physical and psychological effects of war.",
"title": ""
},
{
"paragraph_id": 3,
"text": "Mamet was born in 1947 in Chicago to Lenore June (née Silver), a teacher, and Bernard Morris Mamet, a labor attorney. He is Jewish. His paternal grandparents were Polish Jews. Mamet has said his parents were communists and described himself as a red diaper baby. One of his earliest jobs was as a busboy at Chicago's London House and The Second City. He also worked as an actor, editor for Oui magazine and as a cab-driver. He was educated at the progressive Francis W. Parker School and at Goddard College in Plainfield, Vermont. At the Chicago Public Library Foundation 20th anniversary fundraiser in 2006, though, Mamet announced \"My alma mater is the Chicago Public Library. I got what little educational foundation I got in the third-floor reading room, under the tutelage of a Coca-Cola sign\".",
"title": "Early life"
},
{
"paragraph_id": 4,
"text": "After a move to Chicago's North Side, Mamet encountered theater director Robert Sickinger, and began to work occasionally at Sickinger's Hull House Theatre. This represented the beginning of Mamet's lifelong involvement with the theater.",
"title": "Early life"
},
{
"paragraph_id": 5,
"text": "Mamet is a founding member of the Atlantic Theater Company; he first gained acclaim for a trio of off-Broadway plays in 1976, The Duck Variations, Sexual Perversity in Chicago, and American Buffalo. He was awarded the Pulitzer Prize in 1984 for Glengarry Glen Ross, which received its first Broadway revival in the summer of 2005. His play Race, which opened on Broadway on December 6, 2009, and featured James Spader, David Alan Grier, Kerry Washington, and Richard Thomas in the cast, received mixed reviews. His play The Anarchist, starring Patti LuPone and Debra Winger, in her Broadway debut, opened on Broadway on November 13, 2012, in previews and was scheduled to close on December 16, 2012. His 2017 play The Penitent previewed off-Broadway on February 8, 2017.",
"title": "Career"
},
{
"paragraph_id": 6,
"text": "In 2002, Mamet was inducted into the American Theater Hall of Fame. Mamet later received the PEN/Laura Pels Theater Award for Grand Master of American Theater in 2010.",
"title": "Career"
},
{
"paragraph_id": 7,
"text": "In 2017, Mamet released an online class for writers entitled David Mamet teaches dramatic writing.",
"title": "Career"
},
{
"paragraph_id": 8,
"text": "In 2019 Mamet returned to the London West End with a new play, Bitter Wheat, at the Garrick Theatre, starring John Malkovich.",
"title": "Career"
},
{
"paragraph_id": 9,
"text": "In 2023 it was announced Mamet was writing a new play entitled, Henry Johnson. The production is announced to debut in Los Angeles starring Shia LaBeouf.",
"title": "Career"
},
{
"paragraph_id": 10,
"text": "Mamet's first film work was as a screenwriter, later directing his own scripts.",
"title": "Career"
},
{
"paragraph_id": 11,
"text": "According to Joe Mantegna, Mamet worked as a script doctor for the 1978 film Towing.",
"title": "Career"
},
{
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"text": "Mamet's first produced screenplay was the 1981 production of The Postman Always Rings Twice, based on James M. Cain's novel. He received an Academy Award nomination one year later for the 1982 legal drama, The Verdict. He also wrote the screenplays for The Untouchables (1987), Hoffa (1992), The Edge (1997), Wag the Dog (1997), Ronin (1998), and Hannibal (2001). He received a second Academy Award nomination for Wag the Dog.",
"title": "Career"
},
{
"paragraph_id": 13,
"text": "In 1987, Mamet made his film directing debut with his screenplay House of Games, which won Best Screenplay awards at the 1987 Venice Film Festival and the Film of the Year in 1989 from the London Film Critics' Circle Awards. The film starred his then-wife, Lindsay Crouse, and many longtime stage associates and friends, including fellow Goddard College graduates. Mamet was quoted as saying, \"It was my first film as a director and I needed support, so I stacked the deck.\" After House of Games, Mamet later wrote and directed two more films focusing on the world of con artists, The Spanish Prisoner (1997) and Heist (2001). Among those films, Heist enjoyed the biggest commercial success.",
"title": "Career"
},
{
"paragraph_id": 14,
"text": "Other films that Mamet both wrote and directed include: Things Change (1988), Homicide (1991) (nominated for the Palme d'Or at 1991 Cannes Film Festival and won a \"Screenwriter of the Year\" award for Mamet from the London Film Critics' Circle Awards), Oleanna (1994), The Winslow Boy (1999), State and Main (2000), Spartan (2004), Redbelt (2008), and the 2013 bio-pic TV movie Phil Spector.",
"title": "Career"
},
{
"paragraph_id": 15,
"text": "A feature-length film, a thriller titled Blackbird, was intended for release in 2015, but is still in development.",
"title": "Career"
},
{
"paragraph_id": 16,
"text": "When Mamet adapted his play for the 1992 film Glengarry Glen Ross, he wrote an additional part (including the monologue \"Coffee's for closers\") for Alec Baldwin.",
"title": "Career"
},
{
"paragraph_id": 17,
"text": "Mamet continues to work with an informal repertory company for his films, including Crouse, William H. Macy, Joe Mantegna, and Rebecca Pidgeon, as well as the aforementioned school friends.",
"title": "Career"
},
{
"paragraph_id": 18,
"text": "Mamet rewrote the script for Ronin under the pseudonym \"Richard Weisz\" and turned in an early version of a script for Malcolm X which was rejected by director Spike Lee. Mamet also wrote an unproduced biopic script about Roscoe Arbuckle with Chris Farley intended to portray him. In 2000, Mamet directed a film version of Catastrophe, a one-act play by Samuel Beckett featuring Harold Pinter and John Gielgud (in his final screen performance). In 2008, he wrote and directed the mixed martial arts movie Redbelt, about a martial arts instructor tricked into fighting in a professional bout.",
"title": "Career"
},
{
"paragraph_id": 19,
"text": "In On Directing Film, Mamet advocates for a method of storytelling based on Eisenstein's montage theory, stating that the story should be told through the juxtaposition of uninflected images. This method relies heavily on the cut between scenes, and Mamet urges directors to eliminate as much narration as possible. Mamet asserts that directors should focus on getting the point of a scene across, rather than simply following a protagonist, or adding visually beautiful or intriguing shots. Films should create order from disorder in search of the objective.",
"title": "Career"
},
{
"paragraph_id": 20,
"text": "In 2023, reports emerged that Mamet would direct and co-write a new film titled Assassination, his first film since 2008. The film will center around the Chicago Mob ordering the assassination of John F. Kennedy, and will star Viggo Mortensen, Shia LaBeouf, Courtney Love, Al Pacino, and John Travolta. The film's production is scheduled to start in September 2023.",
"title": "Career"
},
{
"paragraph_id": 21,
"text": "Mamet published the essay collection Writing in Restaurants in 1986, followed by the poetry collection The Hero Pony in 1990. He has also published a series of short plays, monologues and four novels, The Village (1994), The Old Religion (1997), Wilson: A Consideration of the Sources (2000), and Chicago (2018). He has written several non-fiction texts, and children's stories, including True and False: Heresy and Common Sense for the Actor (1997). In 2004 he published a lauded version of the classical Faust story, Faustus, however, when the play was staged in San Francisco during the spring of 2004, it was not well received by critics. On May 1, 2010, Mamet released a graphic novel The Trials of Roderick Spode (The Human Ant).",
"title": "Career"
},
{
"paragraph_id": 22,
"text": "Mamet detailed his conversion from modern liberalism to \"a reformed liberal\" in The Secret Knowledge: On the Dismantling of American Culture in 2011. Mamet published Three War Stories, a collection of novellas, in 2013 ; the novel The Diary of a Porn Star by Priscilla Wriston-Ranger: As Told to David Mamet With an Afterword by Mr. Mamet in 2019; and the political commentary Recessional: The Death of Free Speech and the Cost of a Free Lunch in 2022.",
"title": "Career"
},
{
"paragraph_id": 23,
"text": "Mamet wrote one episode of Hill Street Blues, \"A Wasted Weekend\", that aired in 1987. His then-wife, Lindsay Crouse, appeared in numerous episodes (including that one) as Officer McBride. Mamet is also the creator, producer and frequent writer of the television series The Unit, where he wrote a well-circulated memo to the writing staff. He directed a third-season episode of The Shield with Shawn Ryan. In 2007, Mamet directed two television commercials for Ford Motor Company. The two 30-second ads featured the Ford Edge and were filmed in Mamet's signature style of fast-paced dialogue and clear, simple imagery. Mamet's sister, Lynn, is a producer and writer for television shows, such as The Unit and Law & Order.",
"title": "Career"
},
{
"paragraph_id": 24,
"text": "Mamet has contributed several dramas to BBC Radio through Jarvis & Ayres Productions, including an adaptation of Glengarry Glen Ross for BBC Radio 3 and new dramas for BBC Radio 4. The comedy Keep Your Pantheon (or On the Whole I'd Rather Be in Mesopotamia) was aired in 2007. The Christopher Boy's Communion was another Jarvis & Ayres production, first broadcast on BBC Radio 4 on March 8, 2021.",
"title": "Career"
},
{
"paragraph_id": 25,
"text": "The papers of David Mamet were sold to the Harry Ransom Center at the University of Texas at Austin in 2007 and first opened for research in 2009. The growing collection consists mainly of manuscripts and related production materials for most of his plays, films, and other writings, but also includes his personal journals from 1966 to 2005. In 2015, the Ransom Center secured a second major addition to Mamet's papers, including more recent works. Additional materials relating to Mamet and his career can be found in the Ransom Center's collections of Robert De Niro, Mel Gussow, Tom Stoppard, Sam Shepard, Paul Schrader, Don DeLillo, and John Russell Brown.",
"title": "Career"
},
{
"paragraph_id": 26,
"text": "Mamet's style of writing dialogue, marked by a cynical, street-smart edge, has come to be called Mamet speak. Mamet himself has criticized his (and other writers') tendency to write \"pretty\" at the expense of sound, logical plots. When asked how he developed his style for writing dialogue, Mamet said, \"In my family, in the days prior to television, we liked to while away the evenings by making ourselves miserable, based solely on our ability to speak the language viciously. That's probably where my ability was honed.\"",
"title": "Career"
},
{
"paragraph_id": 27,
"text": "Mamet's plays have frequently sparked debate and controversy. Following a 1992 staging of Oleanna, a play in which a college student accuses her professor of trying to rape her, a critic reported that the play divided the audience by gender and recounted that \"couples emerged screaming at each other\".",
"title": "Career"
},
{
"paragraph_id": 28,
"text": "In his 2014 book David Mamet and Male Friendship, Arthur Holmberg examined Mamet's portrayal of male friendships, especially focusing on the contradictions and ambiguities of male bonding as dramatized in Mamet's plays and films.",
"title": "Career"
},
{
"paragraph_id": 29,
"text": "Mamet and actress Lindsay Crouse married in 1977 and divorced in 1990. The couple have two children. Mamet has been married to actress and singer-songwriter Rebecca Pidgeon since 1991, and they have two children. Mamet and Pidgeon live in Santa Monica, California.",
"title": "Personal life"
},
{
"paragraph_id": 30,
"text": "Mamet is a Reform Jew and strongly pro-Israel.",
"title": "Personal life"
},
{
"paragraph_id": 31,
"text": "In 2005, Mamet became a contributing blogger for The Huffington Post, drawing satirical cartoons with themes including political strife in Israel. In a 2008 essay at The Village Voice titled \"Why I Am No Longer a 'Brain-Dead Liberal'\" he discussed how his political views had shifted from liberalism to conservatism. In interviews, Mamet has highlighted his agreement with free market theorists such as Friedrich Hayek, the historian Paul Johnson, and economist Thomas Sowell, whom Mamet called \"one of our greatest minds\". In 2022, Mamet declined to explicitly label himself a Republican, but described himself as a conservative who \"would like to conserve those things I grew up with: the love of family, the love of the country, love of service, love of God, love of community\".",
"title": "Personal life"
},
{
"paragraph_id": 32,
"text": "During promotion of a book, Mamet said British people had \"a taint of anti-semitism,\" claiming they \"want to give [Israel] away to some people whose claim is rather dubious.\" In the same interview, Mamet went on to say that \"there are famous dramatists and novelists [in the UK] whose works are full of anti-Semitic filth.\" He refused to give examples because of British libel laws (the interview was conducted in New York City for the Financial Times). He is known for his pro-Israel positions; in his book The Secret Knowledge he claimed that \"Israelis would like to live in peace within their borders; the Arabs would like to kill them all.\"",
"title": "Personal life"
},
{
"paragraph_id": 33,
"text": "Mamet endorsed Republican Mitt Romney for president in 2012, and wrote an article for The Jewish Journal of Greater Los Angeles imploring fellow Jewish Americans to vote for Romney.",
"title": "Personal life"
},
{
"paragraph_id": 34,
"text": "In an essay for Newsweek, published on January 29, 2013, Mamet argued against gun control laws: \"It was intended to guard us against this inevitable decay of government that the Constitution was written. Its purpose was and is not to enthrone a Government superior to an imperfect and confused electorate, but to protect us from such a government.\"",
"title": "Personal life"
},
{
"paragraph_id": 35,
"text": "Mamet has described the NFL anthem protests as \"absolutely fucking despicable\". In a 2020 interview, he described Donald Trump as a \"great president\" and supported his re-election. After Trump lost the election, Mamet appeared to endorse claims that the election had been illegitimate in his 2022 book Recessional: The Death of Free Speech and the Cost of a Free Lunch, though shortly after its publication, he said he \"misspoke\" on the subject.",
"title": "Personal life"
},
{
"paragraph_id": 36,
"text": "In 2022, Mamet made comments in support of Florida's Parental Rights in Education Act, called the \"Don't Say Gay\" bill by its critics, which restricts what public school teachers in Florida can discuss with children in kindergarten through third grade about sexual orientation and gender identity. In an interview with Fox News, Mamet claimed that the law was necessary because teachers \"are abusing [children] mentally and using sex to do so\", further alleging that \"teachers are inclined, particularly men because men are predators, to pedophilia\".",
"title": "Personal life"
},
{
"paragraph_id": 37,
"text": "Films",
"title": "Works"
},
{
"paragraph_id": 38,
"text": "Short films",
"title": "Works"
},
{
"paragraph_id": 39,
"text": "Television",
"title": "Works"
},
{
"paragraph_id": 40,
"text": "Acting roles",
"title": "Works"
},
{
"paragraph_id": 41,
"text": "Unrealized projects",
"title": "Works"
}
] | David Alan Mamet is an American playwright, filmmaker, and author. He won a Pulitzer Prize and received Tony nominations for his plays Glengarry Glen Ross (1984) and Speed-the-Plow (1988). He first gained critical acclaim for a trio of off-Broadway 1970s plays: The Duck Variations, Sexual Perversity in Chicago, and American Buffalo. His plays Race and The Penitent, respectively, opened on Broadway in 2009 and previewed off-Broadway in 2017. Feature films that Mamet both wrote and directed include House of Games (1987), Homicide (1991), The Spanish Prisoner (1997), and his biggest commercial success, Heist (2001). His screenwriting credits include The Postman Always Rings Twice (1981), The Verdict (1982), The Untouchables (1987), Hoffa (1992), Wag the Dog (1997), and Hannibal (2001). Mamet himself wrote the screenplay for the 1992 adaptation of Glengarry Glen Ross, and wrote and directed the 1994 adaptation of his play Oleanna (1992). He created and produced the CBS series The Unit (2006–2009). Mamet's books include: On Directing Film (1991), a commentary and dialogue about film-making; The Old Religion (1997), a novel about the lynching of Leo Frank; Five Cities of Refuge: Weekly Reflections on Genesis, Exodus, Leviticus, Numbers and Deuteronomy (2004), a Torah commentary with Rabbi Lawrence Kushner; The Wicked Son (2006), a study of Jewish self-hatred and antisemitism; Bambi vs. Godzilla, a commentary on the movie business; The Secret Knowledge: On the Dismantling of American Culture (2011), a commentary on cultural and political issues; and Three War Stories (2013), a trio of novellas about the physical and psychological effects of war. | 2001-08-23T03:37:39Z | 2023-12-29T00:19:31Z | [
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8,352 | December 6 | December 6 is the 340th day of the year (341st in leap years) in the Gregorian calendar; 25 days remain until the end of the year. | [
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8,353 | December 5 | December 5 is the 339th day of the year (340th in leap years) in the Gregorian calendar; 26 days remain until the end of the year. | [
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8,354 | December 4 | December 4 is the 338th day of the year (339th in leap years) in the Gregorian calendar; 27 days remain until the end of the year. | [
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8,355 | December 3 | December 3 is the 337th day of the year (338th in leap years) in the Gregorian calendar; 28 days remain until the end of the year. | [
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8,356 | December 2 | December 2 is the 336th day of the year (337th in leap years) in the Gregorian calendar; 29 days remain until the end of the year. | [
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8,357 | December 1 | December 1 is the 335th day of the year (336th in leap years) in the Gregorian calendar; 30 days remain until the end of the year. | [
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8,359 | December 24 | December 24 is the 358th day of the year (359th in leap years) in the Gregorian calendar; seven days remain until the end of the year. | [
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8,360 | December 26 | December 26 is the 360th day of the year (361st in leap years) in the Gregorian calendar; five days remain until the end of the year. | [
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8,361 | Definable real number | Informally, a definable real number is a real number that can be uniquely specified by its description. The description may be expressed as a construction or as a formula of a formal language. For example, the positive square root of 2, 2 {\displaystyle {\sqrt {2}}} , can be defined as the unique positive solution to the equation x 2 = 2 {\displaystyle x^{2}=2} , and it can be constructed with a compass and straightedge.
Different choices of a formal language or its interpretation give rise to different notions of definability. Specific varieties of definable numbers include the constructible numbers of geometry, the algebraic numbers, and the computable numbers. Because formal languages can have only countably many formulas, every notion of definable numbers has at most countably many definable real numbers. However, by Cantor's diagonal argument, there are uncountably many real numbers, so almost every real number is undefinable.
One way of specifying a real number uses geometric techniques. A real number r {\displaystyle r} is a constructible number if there is a method to construct a line segment of length r {\displaystyle r} using a compass and straightedge, beginning with a fixed line segment of length 1.
Each positive integer, and each positive rational number, is constructible. The positive square root of 2 is constructible. However, the cube root of 2 is not constructible; this is related to the impossibility of doubling the cube.
A real number r {\displaystyle r} is called a real algebraic number if there is a polynomial p ( x ) {\displaystyle p(x)} , with only integer coefficients, so that r {\displaystyle r} is a root of p {\displaystyle p} , that is, p ( r ) = 0 {\displaystyle p(r)=0} . Each real algebraic number can be defined individually using the order relation on the reals. For example, if a polynomial q ( x ) {\displaystyle q(x)} has 5 real roots, the third one can be defined as the unique r {\displaystyle r} such that q ( r ) = 0 {\displaystyle q(r)=0} and such that there are two distinct numbers less than r {\displaystyle r} at which q {\displaystyle q} is zero.
All rational numbers are algebraic, and all constructible numbers are algebraic. There are numbers such as the cube root of 2 which are algebraic but not constructible.
The real algebraic numbers form a subfield of the real numbers. This means that 0 and 1 are algebraic numbers and, moreover, if a {\displaystyle a} and b {\displaystyle b} are algebraic numbers, then so are a + b {\displaystyle a+b} , a − b {\displaystyle a-b} , a b {\displaystyle ab} and, if b {\displaystyle b} is nonzero, a / b {\displaystyle a/b} .
The real algebraic numbers also have the property, which goes beyond being a subfield of the reals, that for each positive integer n {\displaystyle n} and each real algebraic number a {\displaystyle a} , all of the n {\displaystyle n} th roots of a {\displaystyle a} that are real numbers are also algebraic.
There are only countably many algebraic numbers, but there are uncountably many real numbers, so in the sense of cardinality most real numbers are not algebraic. This nonconstructive proof that not all real numbers are algebraic was first published by Georg Cantor in his 1874 paper "On a Property of the Collection of All Real Algebraic Numbers".
Non-algebraic numbers are called transcendental numbers. The best known transcendental numbers are π and e.
A real number is a computable number if there is an algorithm that, given a natural number n {\displaystyle n} , produces a decimal expansion for the number accurate to n {\displaystyle n} decimal places. This notion was introduced by Alan Turing in 1936.
The computable numbers include the algebraic numbers along with many transcendental numbers including π {\displaystyle \pi } and e {\displaystyle e} . Like the algebraic numbers, the computable numbers also form a subfield of the real numbers, and the positive computable numbers are closed under taking n {\displaystyle n} th roots for each positive n {\displaystyle n} .
Not all real numbers are computable. Specific examples of noncomputable real numbers include the limits of Specker sequences, and algorithmically random real numbers such as Chaitin's Ω numbers.
Another notion of definability comes from the formal theories of arithmetic, such as Peano arithmetic. The language of arithmetic has symbols for 0, 1, the successor operation, addition, and multiplication, intended to be interpreted in the usual way over the natural numbers. Because no variables of this language range over the real numbers, a different sort of definability is needed to refer to real numbers. A real number a {\displaystyle a} is definable in the language of arithmetic (or arithmetical) if its Dedekind cut can be defined as a predicate in that language; that is, if there is a first-order formula φ {\displaystyle \varphi } in the language of arithmetic, with three free variables, such that
Here m, n, and p range over nonnegative integers.
The second-order language of arithmetic is the same as the first-order language, except that variables and quantifiers are allowed to range over sets of naturals. A real that is second-order definable in the language of arithmetic is called analytical.
Every computable real number is arithmetical, and the arithmetical numbers form a subfield of the reals, as do the analytical numbers. Every arithmetical number is analytical, but not every analytical number is arithmetical. Because there are only countably many analytical numbers, most real numbers are not analytical, and thus also not arithmetical.
Every computable number is arithmetical, but not every arithmetical number is computable. For example, the limit of a Specker sequence is an arithmetical number that is not computable.
The definitions of arithmetical and analytical reals can be stratified into the arithmetical hierarchy and analytical hierarchy. In general, a real is computable if and only if its Dedekind cut is at level Δ 1 0 {\displaystyle \Delta _{1}^{0}} of the arithmetical hierarchy, one of the lowest levels. Similarly, the reals with arithmetical Dedekind cuts form the lowest level of the analytical hierarchy.
A real number a {\displaystyle a} is first-order definable in the language of set theory, without parameters, if there is a formula φ {\displaystyle \varphi } in the language of set theory, with one free variable, such that a {\displaystyle a} is the unique real number such that φ ( a ) {\displaystyle \varphi (a)} holds. This notion cannot be expressed as a formula in the language of set theory.
All analytical numbers, and in particular all computable numbers, are definable in the language of set theory. Thus the real numbers definable in the language of set theory include all familiar real numbers such as 0, 1, π {\displaystyle \pi } , e {\displaystyle e} , et cetera, along with all algebraic numbers. Assuming that they form a set in the model, the real numbers definable in the language of set theory over a particular model of ZFC form a field.
Each set model M {\displaystyle M} of ZFC set theory that contains uncountably many real numbers must contain real numbers that are not definable within M {\displaystyle M} (without parameters). This follows from the fact that there are only countably many formulas, and so only countably many elements of M {\displaystyle M} can be definable over M {\displaystyle M} . Thus, if M {\displaystyle M} has uncountably many real numbers, one can prove from "outside" M {\displaystyle M} that not every real number of M {\displaystyle M} is definable over M {\displaystyle M} .
This argument becomes more problematic if it is applied to class models of ZFC, such as the von Neumann universe. The assertion "the real number x {\displaystyle x} is definable over the class model N {\displaystyle N} " cannot be expressed as a formula of ZFC. Similarly, the question of whether the von Neumann universe contains real numbers that it cannot define cannot be expressed as a sentence in the language of ZFC. Moreover, there are countable models of ZFC in which all real numbers, all sets of real numbers, functions on the reals, etc. are definable. | [
{
"paragraph_id": 0,
"text": "Informally, a definable real number is a real number that can be uniquely specified by its description. The description may be expressed as a construction or as a formula of a formal language. For example, the positive square root of 2, 2 {\\displaystyle {\\sqrt {2}}} , can be defined as the unique positive solution to the equation x 2 = 2 {\\displaystyle x^{2}=2} , and it can be constructed with a compass and straightedge.",
"title": ""
},
{
"paragraph_id": 1,
"text": "Different choices of a formal language or its interpretation give rise to different notions of definability. Specific varieties of definable numbers include the constructible numbers of geometry, the algebraic numbers, and the computable numbers. Because formal languages can have only countably many formulas, every notion of definable numbers has at most countably many definable real numbers. However, by Cantor's diagonal argument, there are uncountably many real numbers, so almost every real number is undefinable.",
"title": ""
},
{
"paragraph_id": 2,
"text": "One way of specifying a real number uses geometric techniques. A real number r {\\displaystyle r} is a constructible number if there is a method to construct a line segment of length r {\\displaystyle r} using a compass and straightedge, beginning with a fixed line segment of length 1.",
"title": "Constructible numbers"
},
{
"paragraph_id": 3,
"text": "Each positive integer, and each positive rational number, is constructible. The positive square root of 2 is constructible. However, the cube root of 2 is not constructible; this is related to the impossibility of doubling the cube.",
"title": "Constructible numbers"
},
{
"paragraph_id": 4,
"text": "A real number r {\\displaystyle r} is called a real algebraic number if there is a polynomial p ( x ) {\\displaystyle p(x)} , with only integer coefficients, so that r {\\displaystyle r} is a root of p {\\displaystyle p} , that is, p ( r ) = 0 {\\displaystyle p(r)=0} . Each real algebraic number can be defined individually using the order relation on the reals. For example, if a polynomial q ( x ) {\\displaystyle q(x)} has 5 real roots, the third one can be defined as the unique r {\\displaystyle r} such that q ( r ) = 0 {\\displaystyle q(r)=0} and such that there are two distinct numbers less than r {\\displaystyle r} at which q {\\displaystyle q} is zero.",
"title": "Real algebraic numbers"
},
{
"paragraph_id": 5,
"text": "All rational numbers are algebraic, and all constructible numbers are algebraic. There are numbers such as the cube root of 2 which are algebraic but not constructible.",
"title": "Real algebraic numbers"
},
{
"paragraph_id": 6,
"text": "The real algebraic numbers form a subfield of the real numbers. This means that 0 and 1 are algebraic numbers and, moreover, if a {\\displaystyle a} and b {\\displaystyle b} are algebraic numbers, then so are a + b {\\displaystyle a+b} , a − b {\\displaystyle a-b} , a b {\\displaystyle ab} and, if b {\\displaystyle b} is nonzero, a / b {\\displaystyle a/b} .",
"title": "Real algebraic numbers"
},
{
"paragraph_id": 7,
"text": "The real algebraic numbers also have the property, which goes beyond being a subfield of the reals, that for each positive integer n {\\displaystyle n} and each real algebraic number a {\\displaystyle a} , all of the n {\\displaystyle n} th roots of a {\\displaystyle a} that are real numbers are also algebraic.",
"title": "Real algebraic numbers"
},
{
"paragraph_id": 8,
"text": "There are only countably many algebraic numbers, but there are uncountably many real numbers, so in the sense of cardinality most real numbers are not algebraic. This nonconstructive proof that not all real numbers are algebraic was first published by Georg Cantor in his 1874 paper \"On a Property of the Collection of All Real Algebraic Numbers\".",
"title": "Real algebraic numbers"
},
{
"paragraph_id": 9,
"text": "Non-algebraic numbers are called transcendental numbers. The best known transcendental numbers are π and e.",
"title": "Real algebraic numbers"
},
{
"paragraph_id": 10,
"text": "A real number is a computable number if there is an algorithm that, given a natural number n {\\displaystyle n} , produces a decimal expansion for the number accurate to n {\\displaystyle n} decimal places. This notion was introduced by Alan Turing in 1936.",
"title": "Computable real numbers"
},
{
"paragraph_id": 11,
"text": "The computable numbers include the algebraic numbers along with many transcendental numbers including π {\\displaystyle \\pi } and e {\\displaystyle e} . Like the algebraic numbers, the computable numbers also form a subfield of the real numbers, and the positive computable numbers are closed under taking n {\\displaystyle n} th roots for each positive n {\\displaystyle n} .",
"title": "Computable real numbers"
},
{
"paragraph_id": 12,
"text": "Not all real numbers are computable. Specific examples of noncomputable real numbers include the limits of Specker sequences, and algorithmically random real numbers such as Chaitin's Ω numbers.",
"title": "Computable real numbers"
},
{
"paragraph_id": 13,
"text": "Another notion of definability comes from the formal theories of arithmetic, such as Peano arithmetic. The language of arithmetic has symbols for 0, 1, the successor operation, addition, and multiplication, intended to be interpreted in the usual way over the natural numbers. Because no variables of this language range over the real numbers, a different sort of definability is needed to refer to real numbers. A real number a {\\displaystyle a} is definable in the language of arithmetic (or arithmetical) if its Dedekind cut can be defined as a predicate in that language; that is, if there is a first-order formula φ {\\displaystyle \\varphi } in the language of arithmetic, with three free variables, such that",
"title": "Definability in arithmetic"
},
{
"paragraph_id": 14,
"text": "Here m, n, and p range over nonnegative integers.",
"title": "Definability in arithmetic"
},
{
"paragraph_id": 15,
"text": "The second-order language of arithmetic is the same as the first-order language, except that variables and quantifiers are allowed to range over sets of naturals. A real that is second-order definable in the language of arithmetic is called analytical.",
"title": "Definability in arithmetic"
},
{
"paragraph_id": 16,
"text": "Every computable real number is arithmetical, and the arithmetical numbers form a subfield of the reals, as do the analytical numbers. Every arithmetical number is analytical, but not every analytical number is arithmetical. Because there are only countably many analytical numbers, most real numbers are not analytical, and thus also not arithmetical.",
"title": "Definability in arithmetic"
},
{
"paragraph_id": 17,
"text": "Every computable number is arithmetical, but not every arithmetical number is computable. For example, the limit of a Specker sequence is an arithmetical number that is not computable.",
"title": "Definability in arithmetic"
},
{
"paragraph_id": 18,
"text": "The definitions of arithmetical and analytical reals can be stratified into the arithmetical hierarchy and analytical hierarchy. In general, a real is computable if and only if its Dedekind cut is at level Δ 1 0 {\\displaystyle \\Delta _{1}^{0}} of the arithmetical hierarchy, one of the lowest levels. Similarly, the reals with arithmetical Dedekind cuts form the lowest level of the analytical hierarchy.",
"title": "Definability in arithmetic"
},
{
"paragraph_id": 19,
"text": "A real number a {\\displaystyle a} is first-order definable in the language of set theory, without parameters, if there is a formula φ {\\displaystyle \\varphi } in the language of set theory, with one free variable, such that a {\\displaystyle a} is the unique real number such that φ ( a ) {\\displaystyle \\varphi (a)} holds. This notion cannot be expressed as a formula in the language of set theory.",
"title": "Definability in models of ZFC"
},
{
"paragraph_id": 20,
"text": "All analytical numbers, and in particular all computable numbers, are definable in the language of set theory. Thus the real numbers definable in the language of set theory include all familiar real numbers such as 0, 1, π {\\displaystyle \\pi } , e {\\displaystyle e} , et cetera, along with all algebraic numbers. Assuming that they form a set in the model, the real numbers definable in the language of set theory over a particular model of ZFC form a field.",
"title": "Definability in models of ZFC"
},
{
"paragraph_id": 21,
"text": "Each set model M {\\displaystyle M} of ZFC set theory that contains uncountably many real numbers must contain real numbers that are not definable within M {\\displaystyle M} (without parameters). This follows from the fact that there are only countably many formulas, and so only countably many elements of M {\\displaystyle M} can be definable over M {\\displaystyle M} . Thus, if M {\\displaystyle M} has uncountably many real numbers, one can prove from \"outside\" M {\\displaystyle M} that not every real number of M {\\displaystyle M} is definable over M {\\displaystyle M} .",
"title": "Definability in models of ZFC"
},
{
"paragraph_id": 22,
"text": "This argument becomes more problematic if it is applied to class models of ZFC, such as the von Neumann universe. The assertion \"the real number x {\\displaystyle x} is definable over the class model N {\\displaystyle N} \" cannot be expressed as a formula of ZFC. Similarly, the question of whether the von Neumann universe contains real numbers that it cannot define cannot be expressed as a sentence in the language of ZFC. Moreover, there are countable models of ZFC in which all real numbers, all sets of real numbers, functions on the reals, etc. are definable.",
"title": "Definability in models of ZFC"
}
] | Informally, a definable real number is a real number that can be uniquely specified by its description. The description may be expressed as a construction or as a formula of a formal language. For example, the positive square root of 2, 2 , can be defined as the unique positive solution to the equation x 2 = 2 , and it can be constructed with a compass and straightedge. Different choices of a formal language or its interpretation give rise to different notions of definability. Specific varieties of definable numbers include the constructible numbers of geometry, the algebraic numbers, and the computable numbers. Because formal languages can have only countably many formulas, every notion of definable numbers has at most countably many definable real numbers. However, by Cantor's diagonal argument, there are uncountably many real numbers, so almost every real number is undefinable. | 2001-09-06T18:13:18Z | 2023-12-19T23:30:34Z | [
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8,362 | Diego de Almagro | Diego de Almagro (Spanish: [ˈdjeɣo ðe alˈmaɣɾo]; c. 1475 – July 8, 1538), also known as El Adelantado and El Viejo, was a Spanish conquistador known for his exploits in western South America. He participated with Francisco Pizarro in the Spanish conquest of Peru. While subduing the Inca Empire he laid the foundation for Quito and Trujillo as Spanish cities in present-day Ecuador and Peru respectively. From Peru, Almagro led the first Spanish military expedition to central Chile. Back in Peru, a longstanding conflict with Pizarro over the control of the former Inca capital of Cuzco erupted into a civil war between the two bands of conquistadores. In the battle of Las Salinas in 1538, Almagro was defeated by the Pizarro brothers and months later he was executed.
The origins of Diego de Almagro were humble. He was born in 1475 in the village of Almagro or in Malagón, in Ciudad Real, where he was given the name of the village for his surname as he was the illegitimate son of Juan de Montenegro and Elvira Gutiérrez. In order to preserve the honor of his mother, her relatives took the infant Diego and took him to the nearby town of Bolaños de Calatrava, where he was raised by Sancha López del Peral, later moving to Aldea del Rey.
At the age of four he returned to Almagro, and was placed under the tutelage of an uncle named Hernán Gutiérrez. At age fifteen he ran away from home because of his uncle's harshness. He went to the home of his mother, who was now living with her new husband, to tell her what had happened and that he was going to travel the world, and asked for some bread. His mother, anguished, gave him a piece of bread and some coins and said: "Take, son, and do not give me more trouble, and go, and God help you in your adventure."
He went to Seville and after probably stealing to survive, Almagro became a criado or servant of Don Luis Gonzalez de Polanco, one of the four Alcaldes de la Casa y Corte de Su Majestad and later a Counselor of the Catholic Monarchs. While living in Seville, Almagro stabbed another servant in an argument, inflicting serious enough injuries that he was to be tried in court.
Don Luis, using his influence, prevailed upon Don Pedro Arias Dávila to allow Almagro to embark in one of the ships going to the New World from the port of Sanlucar de Barrameda. The Casa de Contratacion (royal agency for the Spanish Empire) required that the men who crossed the Atlantic provide their own weapons, clothes, and farming tools, which Don Polanco provided to his servant.
Diego de Almagro, now in his late thirties, arrived in the New World on June 30, 1514, with the expedition that Ferdinand II of Aragon had sent under the leadership of Dávila. The expedition arrived at the city of Santa María la Antigua del Darién, Panama, where many other future conquistadors were already assembled, among them Francisco Pizarro.
There are not many details of Almagro's activities during this period, but it is known that he accompanied various sailors who departed from Darien between 1514 and 1515. He eventually returned and settled in Darien, where he was granted an encomienda, building a house and making a living from agriculture.
Almagro undertook his first independent conquest on November 1515, commanding 260 men as he founded Villa del Acla, named after the Indian place. Due to illness he had to hand over command to Gaspar de Espinosa.
Espinosa decided to undertake a new expedition, which departed in December 1515 with 200 men, including Almagro and Francisco Pizarro, who for the first time was designated as a captain. During this expedition, which lasted 14 months, Almagro, Pizarro and Hernando de Luque became close friends.
Also during this time Almagro established a friendship with Vasco Núñez de Balboa, who was in charge of Acla. Almagro wanted to have a ship built with the remaining materials of the Espinosa expedition, to be finished on the coast of the "Great South Sea", as the Pacific Ocean was first called by the Spanish. Current historians do not believe that Almagro was expected to participate in Balboa's expedition and probably returned to Darien.
Almagro took part in the various expeditions that took place in the Gulf of Panama, including those of Espinosa, which were supported by Balboa's ships. Almagro was recorded as a witness on the lists of natives whom Espinosa ordered to be carried. He remained as an early settler in the newly founded city of Panama, staying there for four years, managing his properties and those of Pizarro. He took Ana Martínez, an indigenous woman, as a common-law wife. In this period, his first son, El Mozo, was born to them.
By 1524 an association of conquest regarding South America was formalized among De Almagro, Pizarro and Luque. By the beginning of August 1524, they had received the requisite permission to discover and conquer lands further south. In the first expedition, De Almagro lost his eye to an arrow shot at the Battle of Punta Quemada. He subsequently remained in Panama to recruit men and gather supplies for the expeditions led by Pizarro.
After several expeditions to South America, Pizarro secured his stay in Peru with the Capitulation on 6 July 1529. During Pizarro's continued exploration of Incan territory, he and his men succeeded in defeating the Inca army under Emperor Atahualpa during the Battle of Cajamarca in 1532. De Almagro joined Pizarro soon afterward, bringing more men and arms.
After Peru fell to the Spanish, both Pizarro and De Almagro initially worked together in the founding of new cities to consolidate their dominions. As such, Pizarro dispatched De Almagro to pursue Quizquiz, fleeing to the Inca Empire's northern city of Quito. Their fellow conquistador Sebastián de Belalcázar, who had gone forth without Pizarro's approval, had already reached Quito and witnessed the destruction of the city by Inca general Rumiñawi. The Inca warrior had ordered the city to be burned and its gold to be buried at an undisclosed location where the Spanish could never find it. The arrival of Pedro de Alvarado from Guatemala, in search of Inca gold further complicated the situation for Almagro and Belalcázar. Alvarado's presence, however, did not last long as he left South America in exchange for monetary compensation from Pizarro.
In an attempt to claim Quito ahead of Belalcázar, in August 1534 De Almagro founded a city on the shores of Laguna de Colta (Colta Lake) in the foothills of Chimborazo, some 200 kilometres (120 mi) south of present-day Quito, and named it "Santiago de Quito." Four months later would come the foundation of the Peruvian city of Trujillo, which Almagro named as "Villa Trujillo de Nueva Castilla" (the Village of Trujillo in New Castille) in honor of Francisco Pizarro's birthplace, Trujillo in Extremadura, Spain. These events were the height of the Pizarro-Almagro friendship, which historians describe as one of the last events in which their friendship soon faded and entered a period of turmoil for the control of the Incan capital of Cuzco.
After splitting the treasure of Inca emperor Atahualpa, both Pizarro and Almagro left towards Cuzco and took the city in 1533. However, De Almagro's friendship with Pizarro showed signs of deterioration in 1526 when Pizarro, in the name of the rest of the conquistadors, called forth the "Capitulacion de Toledo" law in which King Charles I of Spain had laid out his authorization for the conquest of Peru and the awards every conquistador would receive from it. Long before, however, each conquistador had promised to equally split the benefits. Pizarro managed to have a larger stake and awards for himself. Despite this, De Almagro still obtained an important fortune for his services, and the King awarded him in November 1532 the noble title of "Don" and he was assigned a personal coat of arms.
Although by this time Diego de Almagro had already acquired sufficient wealth in the conquest of Peru and was living a luxurious life in Cuzco, the prospect of conquering the lands further south was very attractive to him. Given that the dispute with Pizarro over Cuzco had kept intensifying, Almagro spent a great deal of time and money equipping a company of 500 men for a new exploration south of Peru.
By 1534 the Spanish crown had determined to split the region in two parallel lines, forming the governorship of "Nueva Castilla" (from the 1° to the 14° latitude, close to Pisco), and that of "Nueva Toledo" (from the 14° to the 25° latitude, in Taltal, Chile), assigning the first to Francisco Pizarro and the second to Diego de Almagro. The crown had previously assigned Almagro the governorship of Cuzco, and as such De Almagro was heading there when Charles V divided the territory between Nueva Castilla and Nuevo Toledo. This might have been the reason why Almagro did not immediately confront Pizarro for Cuzco, and promptly decided to embark on his new quest for the discovery of the riches of Chile.
Charles V had given Diego a grant extending two hundred leagues south of Francisco Pizarro's. Francisco and Diego concluded a new contract on 12 June 1535, in which they agreed to share future discoveries equally. Diego raised an expedition for Chile, expecting it "would lead to even greater riches than they had found in Peru." Almagro prepared the way by sending ahead three of his Spanish soldiers, the religious chief of the Inca empire, Willaq Umu, and Paullo Topa, brother of Manco Inca Yupanqui. De Almagro sent Juan de Saavedra forward with one hundred and fifty men, and soon followed them with additional forces. Saavedra established on January 23, 1535, the first Spanish settlement in Bolivia near the Inca regional capital of Paria.
Almagro left Cuzco on July 3, 1535, with his supporters and stopped at Moina until the 20th of that month. Meanwhile, Francisco Pizarro's brother, Juan Pizarro, had arrested Inca Manco Inca Yupanqui, further complicating De Almagro's plans as it heavily increased the dissatisfaction of the Indians submitted to Spanish rule. Not having formally been appointed governor of any territories in the Capitulation of Toledo in 1528, however, forcing him to declare himself adelantado (governor) of Nueva Toledo, or southern Peru and present-day Chile. Some sources suggest Almagro received such a requirement in 1534 by the Spanish king and was officially declared governor of New Toledo.
Once he left Moina, De Almagro followed the Inca trail followed by 750 Spaniards deciding to join him in quest for the gold lost in the ransom of Atahualpa, which had mainly benefited the Pizarro brothers and their supporters. After crossing the Bolivian mountain range and traveling past Lake Titicaca, Almagro arrived on the shores of the Desaguadero River and finally set up camp in Tupiza. From there, the expedition stopped at Chicoana and then turned to the southeast to cross the Andes mountains.
The expedition turned out to be a difficult and exhausting endeavor. The hardest phase was the crossing of the Andean cordilleras: the cold, hunger and tiredness meant the death of various Spanish and natives, but mainly slaves who were not accustomed to such rigorous climate.
Upon this point, De Almagro determined everything was a failure. He ordered a small group under Rodrigo Orgóñez on a reconnaissance of the country to the south.
By luck, these men found the Valley of Copiapó, where Gonzalo Calvo Barrientos, a Spanish soldier whom Pizarro had expelled from Peru for stealing objects the Inca had offered for his ransom, had already established a friendship with the local natives. There, in the valley of the river Copiapó, Almagro took official possession of Chile and claimed it in the name of King Charles V.
De Almagro promptly initiated the exploration of the new territory, starting up the valley the Aconcagua River, where he was well received by the natives. However, the intrigues of his interpreter, Felipillo, who had previously helped Pizarro in dealing with Atahualpa, almost thwarted De Almagro's efforts. Felipillo had secretly urged the local natives to attack the Spanish, but they desisted, not understanding the dangers that they posed. De Almagro directed Gómez de Alvarado along with 100 horsemen and 100 foot to continue the exploration, which ended in the confluence of the Ñuble and Itata rivers. The Battle of Reinohuelén between the Spanish and Mapuche indigenous peoples forced the explorers to return to the north.
De Almagro's own reconnaissance of the land and the bad news of Gómez de Alvarado's encounter with the fierce Mapuche, along with the bitter cold winter that settled ferociously upon them, only served to confirm that everything had failed. He never found gold or the cities which Incan scouts had told him lay ahead, only communities of the indigenous population who lived from subsistence agriculture. Local tribes put up fierce resistance to the Spanish forces. The exploration of the territories of Nueva Toledo, which lasted 2 years, was marked by a complete failure for De Almagro. Despite this, at first he thought staying and founding a city would serve well for his honor. The initial optimism that led Almagro to bring his son he had with the indigenous Panamanian Ana Martínez to Chile had faded.
Some historians have suggested that, but for the urging of his senior explorers, De Almagro would probably have stayed permanently in Chile. He was urged to return to Peru and this time take definitive possession of Cuzco, so as to consolidate an inheritance for his son. Dismayed with his experience in the south, Almagro made plans of return to Peru. He never officially founded a city in the territory of what is now Chile.
The withdrawal of the Spanish from valleys of Chile was violent: Almagro authorized his soldiers to ransack the natives' properties, leaving their soil desolate. In addition, the Spanish soldiers took natives captive to serve as slaves. The locals were captured, tied together, and forced to carry the heavy loads belonging to the conquistadors.
After the exhausting crossing of the Atacama Desert, mainly due to the harsh weather conditions, Almagro finally reached Cuzco, Peru, in 1537. According to some authors, it was during this time that the Spanish term "roto" (torn), used by Peruvians to refer to Chileans, was first coined. De Almagro's disappointed troops returned to Cuzco with their "torn clothes" due to the extensive and laborious passage on foot by the Atacama Desert.
After his return, De Almagro was surprised to learn of the Inca Manco's rebellion. Diego de Almagro sent an embassy to the Inca, but they mistrusted all of the Spaniards by this time. Hernando Pizarro's men formed an uneasy truce with De Almagro's men, surveying to determine the boundaries of their leaders' royal grants. They needed to determine in which portion the city of Cuzco was located. However, De Almagro's troops quickly took the city and imprisoned the Pizarro brothers, Hernando and Gonzalo, on the night of 8 April 1537.
After occupying Cuzco, De Almagro confronted an army sent by Francisco Pizarro to liberate his brothers. Alonso de Alvarado commanded it and was defeated during the Battle of Abancay on July 12, 1537. He and some of his men were imprisoned. Later, Gonzalo Pizarro and De Alvarado escaped prison. Subsequent negotiations between Francisco Pizarro and De Almagro concluded with the liberation of Hernando, the third Pizarro brother, in return for conceding control and administration of Cuzco to De Almagro. Pizarro never intended to give up the city permanently, but was buying time to organize an army strong enough to defeat Almagro's troops.
During this time De Almagro fell ill, and Pizarro and his brothers grabbed the opportunity to defeat him and his followers. The Almagristas were defeated at Las Salinas in April 1538, with Orgóñez being killed on the field of battle. De Almagro fled to Cuzco, still in the hands of his loyal supporters, but found only temporary refuge; the forces of the Pizarro brothers entered the city without resistance. Once captured, Almagro was humiliated by Hernando Pizarro and his requests to appeal to the King were ignored.
When Diego de Almagro begged for his life, Hernando responded:
"-he was surprised to see Almagro demean himself in a manner so unbecoming a brave cavalier, that his fate was no worse than had befallen many a soldier before him; and that, since God had given him the grace to be a Christian, he should employ his remaining moments in making up his account with Heaven!"
Almagro was condemned to death and executed by garrote in his dungeon, and then decapitated, on July 8, 1538. His corpse was taken to the public Plaza Mayor of Cuzco, where a herald proclaimed his crimes. Hernán Ponce de León took his body and buried him in the church of Our Lady of Mercy in Cuzco.
Diego de Almagro II (1520–1542), known as El Mozo (The Lad), son of Diego de Almagro I, whose mother was an Indian girl of Panama, became the foil of the conspirators who had put Pizarro to the sword. Pizarro was murdered on June 26, 1541; the conspirators promptly proclaimed the lad De Almagro Governor of Peru. From various causes, all of the conspirators either died or were killed except for one, who was executed after the lad Almagro gave an order. The lad De Almagro fought the desperate battle of Chupas on September 16, 1542, escaped to Cuzco, but was arrested, immediately condemned to death, and executed in the great square of the city. | [
{
"paragraph_id": 0,
"text": "Diego de Almagro (Spanish: [ˈdjeɣo ðe alˈmaɣɾo]; c. 1475 – July 8, 1538), also known as El Adelantado and El Viejo, was a Spanish conquistador known for his exploits in western South America. He participated with Francisco Pizarro in the Spanish conquest of Peru. While subduing the Inca Empire he laid the foundation for Quito and Trujillo as Spanish cities in present-day Ecuador and Peru respectively. From Peru, Almagro led the first Spanish military expedition to central Chile. Back in Peru, a longstanding conflict with Pizarro over the control of the former Inca capital of Cuzco erupted into a civil war between the two bands of conquistadores. In the battle of Las Salinas in 1538, Almagro was defeated by the Pizarro brothers and months later he was executed.",
"title": ""
},
{
"paragraph_id": 1,
"text": "The origins of Diego de Almagro were humble. He was born in 1475 in the village of Almagro or in Malagón, in Ciudad Real, where he was given the name of the village for his surname as he was the illegitimate son of Juan de Montenegro and Elvira Gutiérrez. In order to preserve the honor of his mother, her relatives took the infant Diego and took him to the nearby town of Bolaños de Calatrava, where he was raised by Sancha López del Peral, later moving to Aldea del Rey.",
"title": "Early years"
},
{
"paragraph_id": 2,
"text": "At the age of four he returned to Almagro, and was placed under the tutelage of an uncle named Hernán Gutiérrez. At age fifteen he ran away from home because of his uncle's harshness. He went to the home of his mother, who was now living with her new husband, to tell her what had happened and that he was going to travel the world, and asked for some bread. His mother, anguished, gave him a piece of bread and some coins and said: \"Take, son, and do not give me more trouble, and go, and God help you in your adventure.\"",
"title": "Early years"
},
{
"paragraph_id": 3,
"text": "He went to Seville and after probably stealing to survive, Almagro became a criado or servant of Don Luis Gonzalez de Polanco, one of the four Alcaldes de la Casa y Corte de Su Majestad and later a Counselor of the Catholic Monarchs. While living in Seville, Almagro stabbed another servant in an argument, inflicting serious enough injuries that he was to be tried in court.",
"title": "Early years"
},
{
"paragraph_id": 4,
"text": "Don Luis, using his influence, prevailed upon Don Pedro Arias Dávila to allow Almagro to embark in one of the ships going to the New World from the port of Sanlucar de Barrameda. The Casa de Contratacion (royal agency for the Spanish Empire) required that the men who crossed the Atlantic provide their own weapons, clothes, and farming tools, which Don Polanco provided to his servant.",
"title": "Early years"
},
{
"paragraph_id": 5,
"text": "Diego de Almagro, now in his late thirties, arrived in the New World on June 30, 1514, with the expedition that Ferdinand II of Aragon had sent under the leadership of Dávila. The expedition arrived at the city of Santa María la Antigua del Darién, Panama, where many other future conquistadors were already assembled, among them Francisco Pizarro.",
"title": "Arrival in America"
},
{
"paragraph_id": 6,
"text": "There are not many details of Almagro's activities during this period, but it is known that he accompanied various sailors who departed from Darien between 1514 and 1515. He eventually returned and settled in Darien, where he was granted an encomienda, building a house and making a living from agriculture.",
"title": "Arrival in America"
},
{
"paragraph_id": 7,
"text": "Almagro undertook his first independent conquest on November 1515, commanding 260 men as he founded Villa del Acla, named after the Indian place. Due to illness he had to hand over command to Gaspar de Espinosa.",
"title": "Arrival in America"
},
{
"paragraph_id": 8,
"text": "Espinosa decided to undertake a new expedition, which departed in December 1515 with 200 men, including Almagro and Francisco Pizarro, who for the first time was designated as a captain. During this expedition, which lasted 14 months, Almagro, Pizarro and Hernando de Luque became close friends.",
"title": "Arrival in America"
},
{
"paragraph_id": 9,
"text": "Also during this time Almagro established a friendship with Vasco Núñez de Balboa, who was in charge of Acla. Almagro wanted to have a ship built with the remaining materials of the Espinosa expedition, to be finished on the coast of the \"Great South Sea\", as the Pacific Ocean was first called by the Spanish. Current historians do not believe that Almagro was expected to participate in Balboa's expedition and probably returned to Darien.",
"title": "Arrival in America"
},
{
"paragraph_id": 10,
"text": "Almagro took part in the various expeditions that took place in the Gulf of Panama, including those of Espinosa, which were supported by Balboa's ships. Almagro was recorded as a witness on the lists of natives whom Espinosa ordered to be carried. He remained as an early settler in the newly founded city of Panama, staying there for four years, managing his properties and those of Pizarro. He took Ana Martínez, an indigenous woman, as a common-law wife. In this period, his first son, El Mozo, was born to them.",
"title": "Arrival in America"
},
{
"paragraph_id": 11,
"text": "By 1524 an association of conquest regarding South America was formalized among De Almagro, Pizarro and Luque. By the beginning of August 1524, they had received the requisite permission to discover and conquer lands further south. In the first expedition, De Almagro lost his eye to an arrow shot at the Battle of Punta Quemada. He subsequently remained in Panama to recruit men and gather supplies for the expeditions led by Pizarro.",
"title": "Conquest of Peru"
},
{
"paragraph_id": 12,
"text": "After several expeditions to South America, Pizarro secured his stay in Peru with the Capitulation on 6 July 1529. During Pizarro's continued exploration of Incan territory, he and his men succeeded in defeating the Inca army under Emperor Atahualpa during the Battle of Cajamarca in 1532. De Almagro joined Pizarro soon afterward, bringing more men and arms.",
"title": "Conquest of Peru"
},
{
"paragraph_id": 13,
"text": "After Peru fell to the Spanish, both Pizarro and De Almagro initially worked together in the founding of new cities to consolidate their dominions. As such, Pizarro dispatched De Almagro to pursue Quizquiz, fleeing to the Inca Empire's northern city of Quito. Their fellow conquistador Sebastián de Belalcázar, who had gone forth without Pizarro's approval, had already reached Quito and witnessed the destruction of the city by Inca general Rumiñawi. The Inca warrior had ordered the city to be burned and its gold to be buried at an undisclosed location where the Spanish could never find it. The arrival of Pedro de Alvarado from Guatemala, in search of Inca gold further complicated the situation for Almagro and Belalcázar. Alvarado's presence, however, did not last long as he left South America in exchange for monetary compensation from Pizarro.",
"title": "Conquest of Peru"
},
{
"paragraph_id": 14,
"text": "In an attempt to claim Quito ahead of Belalcázar, in August 1534 De Almagro founded a city on the shores of Laguna de Colta (Colta Lake) in the foothills of Chimborazo, some 200 kilometres (120 mi) south of present-day Quito, and named it \"Santiago de Quito.\" Four months later would come the foundation of the Peruvian city of Trujillo, which Almagro named as \"Villa Trujillo de Nueva Castilla\" (the Village of Trujillo in New Castille) in honor of Francisco Pizarro's birthplace, Trujillo in Extremadura, Spain. These events were the height of the Pizarro-Almagro friendship, which historians describe as one of the last events in which their friendship soon faded and entered a period of turmoil for the control of the Incan capital of Cuzco.",
"title": "Conquest of Peru"
},
{
"paragraph_id": 15,
"text": "After splitting the treasure of Inca emperor Atahualpa, both Pizarro and Almagro left towards Cuzco and took the city in 1533. However, De Almagro's friendship with Pizarro showed signs of deterioration in 1526 when Pizarro, in the name of the rest of the conquistadors, called forth the \"Capitulacion de Toledo\" law in which King Charles I of Spain had laid out his authorization for the conquest of Peru and the awards every conquistador would receive from it. Long before, however, each conquistador had promised to equally split the benefits. Pizarro managed to have a larger stake and awards for himself. Despite this, De Almagro still obtained an important fortune for his services, and the King awarded him in November 1532 the noble title of \"Don\" and he was assigned a personal coat of arms.",
"title": "Conflict with Pizarro"
},
{
"paragraph_id": 16,
"text": "Although by this time Diego de Almagro had already acquired sufficient wealth in the conquest of Peru and was living a luxurious life in Cuzco, the prospect of conquering the lands further south was very attractive to him. Given that the dispute with Pizarro over Cuzco had kept intensifying, Almagro spent a great deal of time and money equipping a company of 500 men for a new exploration south of Peru.",
"title": "Conflict with Pizarro"
},
{
"paragraph_id": 17,
"text": "By 1534 the Spanish crown had determined to split the region in two parallel lines, forming the governorship of \"Nueva Castilla\" (from the 1° to the 14° latitude, close to Pisco), and that of \"Nueva Toledo\" (from the 14° to the 25° latitude, in Taltal, Chile), assigning the first to Francisco Pizarro and the second to Diego de Almagro. The crown had previously assigned Almagro the governorship of Cuzco, and as such De Almagro was heading there when Charles V divided the territory between Nueva Castilla and Nuevo Toledo. This might have been the reason why Almagro did not immediately confront Pizarro for Cuzco, and promptly decided to embark on his new quest for the discovery of the riches of Chile.",
"title": "Conflict with Pizarro"
},
{
"paragraph_id": 18,
"text": "Charles V had given Diego a grant extending two hundred leagues south of Francisco Pizarro's. Francisco and Diego concluded a new contract on 12 June 1535, in which they agreed to share future discoveries equally. Diego raised an expedition for Chile, expecting it \"would lead to even greater riches than they had found in Peru.\" Almagro prepared the way by sending ahead three of his Spanish soldiers, the religious chief of the Inca empire, Willaq Umu, and Paullo Topa, brother of Manco Inca Yupanqui. De Almagro sent Juan de Saavedra forward with one hundred and fifty men, and soon followed them with additional forces. Saavedra established on January 23, 1535, the first Spanish settlement in Bolivia near the Inca regional capital of Paria.",
"title": "Discovery of Chile"
},
{
"paragraph_id": 19,
"text": "Almagro left Cuzco on July 3, 1535, with his supporters and stopped at Moina until the 20th of that month. Meanwhile, Francisco Pizarro's brother, Juan Pizarro, had arrested Inca Manco Inca Yupanqui, further complicating De Almagro's plans as it heavily increased the dissatisfaction of the Indians submitted to Spanish rule. Not having formally been appointed governor of any territories in the Capitulation of Toledo in 1528, however, forcing him to declare himself adelantado (governor) of Nueva Toledo, or southern Peru and present-day Chile. Some sources suggest Almagro received such a requirement in 1534 by the Spanish king and was officially declared governor of New Toledo.",
"title": "Discovery of Chile"
},
{
"paragraph_id": 20,
"text": "Once he left Moina, De Almagro followed the Inca trail followed by 750 Spaniards deciding to join him in quest for the gold lost in the ransom of Atahualpa, which had mainly benefited the Pizarro brothers and their supporters. After crossing the Bolivian mountain range and traveling past Lake Titicaca, Almagro arrived on the shores of the Desaguadero River and finally set up camp in Tupiza. From there, the expedition stopped at Chicoana and then turned to the southeast to cross the Andes mountains.",
"title": "Discovery of Chile"
},
{
"paragraph_id": 21,
"text": "The expedition turned out to be a difficult and exhausting endeavor. The hardest phase was the crossing of the Andean cordilleras: the cold, hunger and tiredness meant the death of various Spanish and natives, but mainly slaves who were not accustomed to such rigorous climate.",
"title": "Discovery of Chile"
},
{
"paragraph_id": 22,
"text": "Upon this point, De Almagro determined everything was a failure. He ordered a small group under Rodrigo Orgóñez on a reconnaissance of the country to the south.",
"title": "Discovery of Chile"
},
{
"paragraph_id": 23,
"text": "By luck, these men found the Valley of Copiapó, where Gonzalo Calvo Barrientos, a Spanish soldier whom Pizarro had expelled from Peru for stealing objects the Inca had offered for his ransom, had already established a friendship with the local natives. There, in the valley of the river Copiapó, Almagro took official possession of Chile and claimed it in the name of King Charles V.",
"title": "Discovery of Chile"
},
{
"paragraph_id": 24,
"text": "De Almagro promptly initiated the exploration of the new territory, starting up the valley the Aconcagua River, where he was well received by the natives. However, the intrigues of his interpreter, Felipillo, who had previously helped Pizarro in dealing with Atahualpa, almost thwarted De Almagro's efforts. Felipillo had secretly urged the local natives to attack the Spanish, but they desisted, not understanding the dangers that they posed. De Almagro directed Gómez de Alvarado along with 100 horsemen and 100 foot to continue the exploration, which ended in the confluence of the Ñuble and Itata rivers. The Battle of Reinohuelén between the Spanish and Mapuche indigenous peoples forced the explorers to return to the north.",
"title": "Dismayed in Chile"
},
{
"paragraph_id": 25,
"text": "De Almagro's own reconnaissance of the land and the bad news of Gómez de Alvarado's encounter with the fierce Mapuche, along with the bitter cold winter that settled ferociously upon them, only served to confirm that everything had failed. He never found gold or the cities which Incan scouts had told him lay ahead, only communities of the indigenous population who lived from subsistence agriculture. Local tribes put up fierce resistance to the Spanish forces. The exploration of the territories of Nueva Toledo, which lasted 2 years, was marked by a complete failure for De Almagro. Despite this, at first he thought staying and founding a city would serve well for his honor. The initial optimism that led Almagro to bring his son he had with the indigenous Panamanian Ana Martínez to Chile had faded.",
"title": "Dismayed in Chile"
},
{
"paragraph_id": 26,
"text": "Some historians have suggested that, but for the urging of his senior explorers, De Almagro would probably have stayed permanently in Chile. He was urged to return to Peru and this time take definitive possession of Cuzco, so as to consolidate an inheritance for his son. Dismayed with his experience in the south, Almagro made plans of return to Peru. He never officially founded a city in the territory of what is now Chile.",
"title": "Dismayed in Chile"
},
{
"paragraph_id": 27,
"text": "The withdrawal of the Spanish from valleys of Chile was violent: Almagro authorized his soldiers to ransack the natives' properties, leaving their soil desolate. In addition, the Spanish soldiers took natives captive to serve as slaves. The locals were captured, tied together, and forced to carry the heavy loads belonging to the conquistadors.",
"title": "Dismayed in Chile"
},
{
"paragraph_id": 28,
"text": "After the exhausting crossing of the Atacama Desert, mainly due to the harsh weather conditions, Almagro finally reached Cuzco, Peru, in 1537. According to some authors, it was during this time that the Spanish term \"roto\" (torn), used by Peruvians to refer to Chileans, was first coined. De Almagro's disappointed troops returned to Cuzco with their \"torn clothes\" due to the extensive and laborious passage on foot by the Atacama Desert.",
"title": "Return to Peru"
},
{
"paragraph_id": 29,
"text": "After his return, De Almagro was surprised to learn of the Inca Manco's rebellion. Diego de Almagro sent an embassy to the Inca, but they mistrusted all of the Spaniards by this time. Hernando Pizarro's men formed an uneasy truce with De Almagro's men, surveying to determine the boundaries of their leaders' royal grants. They needed to determine in which portion the city of Cuzco was located. However, De Almagro's troops quickly took the city and imprisoned the Pizarro brothers, Hernando and Gonzalo, on the night of 8 April 1537.",
"title": "Return to Peru"
},
{
"paragraph_id": 30,
"text": "After occupying Cuzco, De Almagro confronted an army sent by Francisco Pizarro to liberate his brothers. Alonso de Alvarado commanded it and was defeated during the Battle of Abancay on July 12, 1537. He and some of his men were imprisoned. Later, Gonzalo Pizarro and De Alvarado escaped prison. Subsequent negotiations between Francisco Pizarro and De Almagro concluded with the liberation of Hernando, the third Pizarro brother, in return for conceding control and administration of Cuzco to De Almagro. Pizarro never intended to give up the city permanently, but was buying time to organize an army strong enough to defeat Almagro's troops.",
"title": "Return to Peru"
},
{
"paragraph_id": 31,
"text": "During this time De Almagro fell ill, and Pizarro and his brothers grabbed the opportunity to defeat him and his followers. The Almagristas were defeated at Las Salinas in April 1538, with Orgóñez being killed on the field of battle. De Almagro fled to Cuzco, still in the hands of his loyal supporters, but found only temporary refuge; the forces of the Pizarro brothers entered the city without resistance. Once captured, Almagro was humiliated by Hernando Pizarro and his requests to appeal to the King were ignored.",
"title": "Return to Peru"
},
{
"paragraph_id": 32,
"text": "When Diego de Almagro begged for his life, Hernando responded:",
"title": "Return to Peru"
},
{
"paragraph_id": 33,
"text": "\"-he was surprised to see Almagro demean himself in a manner so unbecoming a brave cavalier, that his fate was no worse than had befallen many a soldier before him; and that, since God had given him the grace to be a Christian, he should employ his remaining moments in making up his account with Heaven!\"",
"title": "Return to Peru"
},
{
"paragraph_id": 34,
"text": "Almagro was condemned to death and executed by garrote in his dungeon, and then decapitated, on July 8, 1538. His corpse was taken to the public Plaza Mayor of Cuzco, where a herald proclaimed his crimes. Hernán Ponce de León took his body and buried him in the church of Our Lady of Mercy in Cuzco.",
"title": "Return to Peru"
},
{
"paragraph_id": 35,
"text": "Diego de Almagro II (1520–1542), known as El Mozo (The Lad), son of Diego de Almagro I, whose mother was an Indian girl of Panama, became the foil of the conspirators who had put Pizarro to the sword. Pizarro was murdered on June 26, 1541; the conspirators promptly proclaimed the lad De Almagro Governor of Peru. From various causes, all of the conspirators either died or were killed except for one, who was executed after the lad Almagro gave an order. The lad De Almagro fought the desperate battle of Chupas on September 16, 1542, escaped to Cuzco, but was arrested, immediately condemned to death, and executed in the great square of the city.",
"title": "El Mozo"
}
] | Diego de Almagro, also known as El Adelantado and El Viejo, was a Spanish conquistador known for his exploits in western South America. He participated with Francisco Pizarro in the Spanish conquest of Peru. While subduing the Inca Empire he laid the foundation for Quito and Trujillo as Spanish cities in present-day Ecuador and Peru respectively. From Peru, Almagro led the first Spanish military expedition to central Chile. Back in Peru, a longstanding conflict with Pizarro over the control of the former Inca capital of Cuzco erupted into a civil war between the two bands of conquistadores. In the battle of Las Salinas in 1538, Almagro was defeated by the Pizarro brothers and months later he was executed. | 2023-07-09T14:08:58Z | [
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] | https://en.wikipedia.org/wiki/Diego_de_Almagro |
|
8,363 | Divinity | Divinity or the divine are things that are either related to, devoted to, or proceeding from a deity. What is or is not divine may be loosely defined, as it is used by different belief systems. Under monotheism and polytheism this is clearly delineated. However, in pantheism and animism this becomes synonymous with concepts of sacredness and transcendence.
The root of the word divinity is the Latin divus meaning of or belonging to a God (deus). The word entered English from Medieval Latin in the 14th century.
Divinity as a quality has two distinct usages:
Overlap occurs between these usages because deities or godly entities are often identical with or identified by the powers and forces that are credited to them — in many cases, a deity is merely a power or force personified — and these powers and forces may then be extended or granted to mortal individuals. For instance, Jehovah is closely associated with storms and thunder throughout much of the Old Testament. He is said to speak in thunder, and thunder is seen as a token of his anger. This power was then extended to prophets like Moses and Samuel, who caused thunderous storms to rain down on their enemies. Divinity always carries connotations of goodness, beauty, beneficence, justice, and other positive, pro-social attributes. In monotheistic faiths there is an equivalent cohort of malefic supernatural beings and powers, such as demons, devils, afreet, etc., which are not conventionally referred to as divine; demonic is often used instead. Polytheistic and animistic systems of belief make no such distinction; gods and other beings of transcendent power often have complex, ignoble, or even incomprehensible motivations for their acts. Note that while the terms demon and demonic are used in monotheistic faiths as antonyms to divine, they are in fact derived from the Greek word daimón (δαίμων), which itself translates as divinity.
There are three distinct usages of divinity and divine in religious discourse:
In monotheistic faiths, the word divinity is often used to refer to the singular God central to that faith. Often the word takes the definite article and is capitalized — "the Divinity" — as though it were a proper name or definitive honorific. Divine — capitalized — may be used as an adjective to refer to the manifestations of such a Divinity or its powers: e.g. "basking in the Divine presence..."
The terms divinity and divine — uncapitalized, and lacking the definite article — are sometimes used to denote 'god(s) or certain other beings and entities which fall short of absolute Godhood but lie outside the human realm.
As previously noted, divinities are closely related to the transcendent force(s) or power(s) credited to them, so much so that in some cases the powers or forces may themselves be invoked independently. This leads to the second usage of the word divine (and less common usage of divinity): to refer to the operation of transcendent power in the world.
In its most direct form, the operation of transcendent power implies some form of divine intervention. For monotheistic and polytheistic faiths this usually implies the direct action of one god or another on the course of human events. In Greek legend, for instance, it was Poseidon (god of the sea) who raised the storms that blew Odysseus's craft off course on his return journey, and Japanese tradition holds that a god-sent wind saved them from Mongol invasion. Prayers or propitiations are often offered to specific gods to garner favorable interventions in particular enterprises: e.g. safe journeys, success in war, or a season of bountiful crops. Many faiths around the world — from Japanese Shinto and Chinese traditional religion, to certain African practices and the faiths derived from those in the Caribbean, to Native American beliefs — hold that ancestral or household deities offer daily protection and blessings. In monotheistic religions, divine intervention may take very direct forms: miracles, visions, or intercessions by blessed figures.
Transcendent force or power may also operate through more subtle and indirect paths. Monotheistic faiths generally support some version of divine providence, which acknowledges that the divinity of the faith has a profound but unknowable plan always unfolding in the world. Unforeseeable, overwhelming, or seemingly unjust events are often thrown on 'the will of the Divine', in deferences like the Muslim inshallah ('as God wills it') and Christian 'God works in mysterious ways'. Often such faiths hold out the possibility of divine retribution as well, where the divinity will unexpectedly bring evil-doers to justice through the conventional workings of the world; from the subtle redressing of minor personal wrongs to such large-scale havoc as the destruction of Sodom and Gomorrah or the biblical Great Flood. Other faiths are even more subtle: the doctrine of karma shared by Buddhism and Hinduism is a divine law similar to divine retribution but without the connotation of punishment: our acts, good or bad, intentional or unintentional, reflect back on us as part of the natural working of the universe. Philosophical Taoism also proposes a transcendent operant principle — transliterated in English as tao or dao, meaning 'the way' — which is neither an entity nor a being per se, but reflects the natural ongoing process of the world. Modern western mysticism and new age philosophy often use the term 'the Divine' as a noun in this latter sense: a non-specific principle or being that gives rise to the world, and acts as the source or wellspring of life. In these latter cases, the faiths do not promote deference, as happens in monotheisms; rather each suggests a path of action that will bring the practitioner into conformance with the divine law: ahimsa — 'no harm' — for Buddhist and Hindu faiths; de or te — 'virtuous action' — in Taoism; and any of numerous practices of peace and love in new age thinking.
In the third usage, extensions of divinity and divine power are credited to living, mortal individuals. Political leaders are known to have claimed actual divinity in certain early societies — the ancient Egyptian Pharaohs being the premier case — taking a role as objects of worship and being credited with superhuman status and powers. More commonly, and more pertinent to recent history, leaders merely claim some form of divine mandate, suggesting that their rule is in accordance with the will of God. The doctrine of the divine right of kings was introduced as late as the 17th century, proposing that kings rule by divine decree; Japanese Emperors ruled by divine mandate until the inception of the Japanese constitution after World War II.
Less politically, most faiths have any number of people that are believed to have been touched by divine forces: saints, prophets, heroes, oracles, martyrs, and enlightened beings, among others. Saint Francis of Assisi, in Catholicism, is said to have received instruction directly from God and it is believed that he grants plenary indulgence to all who confess their sins and visit his chapel on the appropriate day. In Greek mythology, Achilles' mother bathed him in the river Styx to give him immortality, and Hercules — as the son of Zeus — inherited near-godly powers. In religious Taoism, Lao Tsu is venerated as a saint with his own powers. Various individuals in the Buddhist faith, beginning with Siddhartha, are considered to be enlightened, and in religious forms of Buddhism they are credited with divine powers. Christ in the Bible is said to be God's Son and is said to have performed divine miracles.
In general, mortals with divine qualities are carefully distinguished from the deity or deities in their religion's main pantheon. Even the Christian faith, which generally holds Christ to be identical to God, distinguishes between God the Father and Christ the begotten Son. There are, however, certain esoteric and mystical schools of thought, present in many faiths — Sufis in Islam, Gnostics in Christianity, Advaitan Hindus, Zen Buddhists, as well as several non-specific perspectives developed in new age philosophy — which hold that all humans are in essence divine, or unified with the Divine in a non-trivial way. Such divinity, in these faiths, would express itself naturally if it were not obscured by the social and physical worlds we live in; it needs to be brought to the fore through appropriate spiritual practices.
In the New Testament the Greek word θεῖον (theion) in the Douay Version, is translated as "divinity". Examples are below:
The word translated as either "deity", "Godhead", or "divinity" in the Greek New Testament is also the Greek word θεότητος (theotētos), and the one verse that contains it is this: Colossians 2:9
The word "divine" in the New Testament is the Greek word θείας (theias), and is the adjective form of "divinity". Biblical examples from the King James Bible are below:
The most prominent conception of divine entities in the Church of Jesus Christ of Latter-day Saints (LDS Church) is the Godhead, a divine council of three distinct beings: Elohim (the Father), Jehovah (the Son, or Jesus), and the Holy Spirit. Joseph Smith described a nontrinitarian Godhead, with God the Father and Jesus Christ each having individual physical bodies, and the Holy Spirit as a distinct personage with a spirit body. Smith also introduced the existence of a Heavenly Mother in the King Follett Discourse, but very little is acknowledged or known beyond her existence.
Mormons hold a belief in the divine potential of humanity; Smith taught a form of divinization where mortal men and women can become like god through salvation and exaltation. Lorenzo Snow succinctly summarized this using a couplet, which is often repeated within the LDS Church: "As man now is, God once was: As God now is, man may be."
Wiccan views of divinity are generally theistic, and revolve around a Goddess and a Horned God, thereby being generally dualistic. In traditional Wicca, as expressed in the writings of Gerald Gardner and Doreen Valiente, the emphasis is on the theme of divine gender polarity, and the God and Goddess are regarded as equal and opposite divine cosmic forces. In some newer forms of Wicca, such as feminist or Dianic Wicca, the Goddess is given primacy or even exclusivity. In some forms of traditional witchcraft that share a similar duotheistic theology, the Horned God is given precedence over the Goddess.
Epicurean philosophy admits the existence of gods, but since it does not accept the supernatural and teaches that all things are material, posits a theology where the Epicurean gods are physical beings whose bodies are made of atoms and who live in the region between the words (intermundia). Needless to say, these gods do not need our worship, are not creators or maintainers of the cosmos, nor do they answer prayers. Therefore, Epicurean theology belongs properly in the realm of speculation about super-evolved, intelligent extraterrestrial life.
However, Epicurus of Samos (the founder of the School) recognized the utility of religiosity and its central, unifying symbols. He was adamant in his requirement that his disciples be pious, and established two taboos concerning their conception of the gods: they had to believe that their gods were immortal (that is, indestructible and fully self-sufficient) and blessed (happy, or blissful). Outside of that, Epicureans are free to speculate concerning the nature of the highest life forms in the cosmos. | [
{
"paragraph_id": 0,
"text": "Divinity or the divine are things that are either related to, devoted to, or proceeding from a deity. What is or is not divine may be loosely defined, as it is used by different belief systems. Under monotheism and polytheism this is clearly delineated. However, in pantheism and animism this becomes synonymous with concepts of sacredness and transcendence.",
"title": ""
},
{
"paragraph_id": 1,
"text": "The root of the word divinity is the Latin divus meaning of or belonging to a God (deus). The word entered English from Medieval Latin in the 14th century.",
"title": "Etymology"
},
{
"paragraph_id": 2,
"text": "Divinity as a quality has two distinct usages:",
"title": "Usages"
},
{
"paragraph_id": 3,
"text": "Overlap occurs between these usages because deities or godly entities are often identical with or identified by the powers and forces that are credited to them — in many cases, a deity is merely a power or force personified — and these powers and forces may then be extended or granted to mortal individuals. For instance, Jehovah is closely associated with storms and thunder throughout much of the Old Testament. He is said to speak in thunder, and thunder is seen as a token of his anger. This power was then extended to prophets like Moses and Samuel, who caused thunderous storms to rain down on their enemies. Divinity always carries connotations of goodness, beauty, beneficence, justice, and other positive, pro-social attributes. In monotheistic faiths there is an equivalent cohort of malefic supernatural beings and powers, such as demons, devils, afreet, etc., which are not conventionally referred to as divine; demonic is often used instead. Polytheistic and animistic systems of belief make no such distinction; gods and other beings of transcendent power often have complex, ignoble, or even incomprehensible motivations for their acts. Note that while the terms demon and demonic are used in monotheistic faiths as antonyms to divine, they are in fact derived from the Greek word daimón (δαίμων), which itself translates as divinity.",
"title": "Usages"
},
{
"paragraph_id": 4,
"text": "There are three distinct usages of divinity and divine in religious discourse:",
"title": "Usages"
},
{
"paragraph_id": 5,
"text": "In monotheistic faiths, the word divinity is often used to refer to the singular God central to that faith. Often the word takes the definite article and is capitalized — \"the Divinity\" — as though it were a proper name or definitive honorific. Divine — capitalized — may be used as an adjective to refer to the manifestations of such a Divinity or its powers: e.g. \"basking in the Divine presence...\"",
"title": "Usages"
},
{
"paragraph_id": 6,
"text": "The terms divinity and divine — uncapitalized, and lacking the definite article — are sometimes used to denote 'god(s) or certain other beings and entities which fall short of absolute Godhood but lie outside the human realm.",
"title": "Usages"
},
{
"paragraph_id": 7,
"text": "As previously noted, divinities are closely related to the transcendent force(s) or power(s) credited to them, so much so that in some cases the powers or forces may themselves be invoked independently. This leads to the second usage of the word divine (and less common usage of divinity): to refer to the operation of transcendent power in the world.",
"title": "Usages"
},
{
"paragraph_id": 8,
"text": "In its most direct form, the operation of transcendent power implies some form of divine intervention. For monotheistic and polytheistic faiths this usually implies the direct action of one god or another on the course of human events. In Greek legend, for instance, it was Poseidon (god of the sea) who raised the storms that blew Odysseus's craft off course on his return journey, and Japanese tradition holds that a god-sent wind saved them from Mongol invasion. Prayers or propitiations are often offered to specific gods to garner favorable interventions in particular enterprises: e.g. safe journeys, success in war, or a season of bountiful crops. Many faiths around the world — from Japanese Shinto and Chinese traditional religion, to certain African practices and the faiths derived from those in the Caribbean, to Native American beliefs — hold that ancestral or household deities offer daily protection and blessings. In monotheistic religions, divine intervention may take very direct forms: miracles, visions, or intercessions by blessed figures.",
"title": "Usages"
},
{
"paragraph_id": 9,
"text": "Transcendent force or power may also operate through more subtle and indirect paths. Monotheistic faiths generally support some version of divine providence, which acknowledges that the divinity of the faith has a profound but unknowable plan always unfolding in the world. Unforeseeable, overwhelming, or seemingly unjust events are often thrown on 'the will of the Divine', in deferences like the Muslim inshallah ('as God wills it') and Christian 'God works in mysterious ways'. Often such faiths hold out the possibility of divine retribution as well, where the divinity will unexpectedly bring evil-doers to justice through the conventional workings of the world; from the subtle redressing of minor personal wrongs to such large-scale havoc as the destruction of Sodom and Gomorrah or the biblical Great Flood. Other faiths are even more subtle: the doctrine of karma shared by Buddhism and Hinduism is a divine law similar to divine retribution but without the connotation of punishment: our acts, good or bad, intentional or unintentional, reflect back on us as part of the natural working of the universe. Philosophical Taoism also proposes a transcendent operant principle — transliterated in English as tao or dao, meaning 'the way' — which is neither an entity nor a being per se, but reflects the natural ongoing process of the world. Modern western mysticism and new age philosophy often use the term 'the Divine' as a noun in this latter sense: a non-specific principle or being that gives rise to the world, and acts as the source or wellspring of life. In these latter cases, the faiths do not promote deference, as happens in monotheisms; rather each suggests a path of action that will bring the practitioner into conformance with the divine law: ahimsa — 'no harm' — for Buddhist and Hindu faiths; de or te — 'virtuous action' — in Taoism; and any of numerous practices of peace and love in new age thinking.",
"title": "Usages"
},
{
"paragraph_id": 10,
"text": "In the third usage, extensions of divinity and divine power are credited to living, mortal individuals. Political leaders are known to have claimed actual divinity in certain early societies — the ancient Egyptian Pharaohs being the premier case — taking a role as objects of worship and being credited with superhuman status and powers. More commonly, and more pertinent to recent history, leaders merely claim some form of divine mandate, suggesting that their rule is in accordance with the will of God. The doctrine of the divine right of kings was introduced as late as the 17th century, proposing that kings rule by divine decree; Japanese Emperors ruled by divine mandate until the inception of the Japanese constitution after World War II.",
"title": "Usages"
},
{
"paragraph_id": 11,
"text": "Less politically, most faiths have any number of people that are believed to have been touched by divine forces: saints, prophets, heroes, oracles, martyrs, and enlightened beings, among others. Saint Francis of Assisi, in Catholicism, is said to have received instruction directly from God and it is believed that he grants plenary indulgence to all who confess their sins and visit his chapel on the appropriate day. In Greek mythology, Achilles' mother bathed him in the river Styx to give him immortality, and Hercules — as the son of Zeus — inherited near-godly powers. In religious Taoism, Lao Tsu is venerated as a saint with his own powers. Various individuals in the Buddhist faith, beginning with Siddhartha, are considered to be enlightened, and in religious forms of Buddhism they are credited with divine powers. Christ in the Bible is said to be God's Son and is said to have performed divine miracles.",
"title": "Usages"
},
{
"paragraph_id": 12,
"text": "In general, mortals with divine qualities are carefully distinguished from the deity or deities in their religion's main pantheon. Even the Christian faith, which generally holds Christ to be identical to God, distinguishes between God the Father and Christ the begotten Son. There are, however, certain esoteric and mystical schools of thought, present in many faiths — Sufis in Islam, Gnostics in Christianity, Advaitan Hindus, Zen Buddhists, as well as several non-specific perspectives developed in new age philosophy — which hold that all humans are in essence divine, or unified with the Divine in a non-trivial way. Such divinity, in these faiths, would express itself naturally if it were not obscured by the social and physical worlds we live in; it needs to be brought to the fore through appropriate spiritual practices.",
"title": "Usages"
},
{
"paragraph_id": 13,
"text": "In the New Testament the Greek word θεῖον (theion) in the Douay Version, is translated as \"divinity\". Examples are below:",
"title": "In Religions"
},
{
"paragraph_id": 14,
"text": "The word translated as either \"deity\", \"Godhead\", or \"divinity\" in the Greek New Testament is also the Greek word θεότητος (theotētos), and the one verse that contains it is this: Colossians 2:9",
"title": "In Religions"
},
{
"paragraph_id": 15,
"text": "The word \"divine\" in the New Testament is the Greek word θείας (theias), and is the adjective form of \"divinity\". Biblical examples from the King James Bible are below:",
"title": "In Religions"
},
{
"paragraph_id": 16,
"text": "The most prominent conception of divine entities in the Church of Jesus Christ of Latter-day Saints (LDS Church) is the Godhead, a divine council of three distinct beings: Elohim (the Father), Jehovah (the Son, or Jesus), and the Holy Spirit. Joseph Smith described a nontrinitarian Godhead, with God the Father and Jesus Christ each having individual physical bodies, and the Holy Spirit as a distinct personage with a spirit body. Smith also introduced the existence of a Heavenly Mother in the King Follett Discourse, but very little is acknowledged or known beyond her existence.",
"title": "In Religions"
},
{
"paragraph_id": 17,
"text": "Mormons hold a belief in the divine potential of humanity; Smith taught a form of divinization where mortal men and women can become like god through salvation and exaltation. Lorenzo Snow succinctly summarized this using a couplet, which is often repeated within the LDS Church: \"As man now is, God once was: As God now is, man may be.\"",
"title": "In Religions"
},
{
"paragraph_id": 18,
"text": "Wiccan views of divinity are generally theistic, and revolve around a Goddess and a Horned God, thereby being generally dualistic. In traditional Wicca, as expressed in the writings of Gerald Gardner and Doreen Valiente, the emphasis is on the theme of divine gender polarity, and the God and Goddess are regarded as equal and opposite divine cosmic forces. In some newer forms of Wicca, such as feminist or Dianic Wicca, the Goddess is given primacy or even exclusivity. In some forms of traditional witchcraft that share a similar duotheistic theology, the Horned God is given precedence over the Goddess.",
"title": "In Religions"
},
{
"paragraph_id": 19,
"text": "Epicurean philosophy admits the existence of gods, but since it does not accept the supernatural and teaches that all things are material, posits a theology where the Epicurean gods are physical beings whose bodies are made of atoms and who live in the region between the words (intermundia). Needless to say, these gods do not need our worship, are not creators or maintainers of the cosmos, nor do they answer prayers. Therefore, Epicurean theology belongs properly in the realm of speculation about super-evolved, intelligent extraterrestrial life.",
"title": "Epicureanism"
},
{
"paragraph_id": 20,
"text": "However, Epicurus of Samos (the founder of the School) recognized the utility of religiosity and its central, unifying symbols. He was adamant in his requirement that his disciples be pious, and established two taboos concerning their conception of the gods: they had to believe that their gods were immortal (that is, indestructible and fully self-sufficient) and blessed (happy, or blissful). Outside of that, Epicureans are free to speculate concerning the nature of the highest life forms in the cosmos.",
"title": "Epicureanism"
}
] | Divinity or the divine are things that are either related to, devoted to, or proceeding from a deity. What is or is not divine may be loosely defined, as it is used by different belief systems. Under monotheism and polytheism this is clearly delineated. However, in pantheism and animism this becomes synonymous with concepts of sacredness and transcendence. | 2001-08-25T00:29:59Z | 2023-12-28T14:35:35Z | [
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] | https://en.wikipedia.org/wiki/Divinity |
8,367 | Depth of field | The depth of field (DOF) is the distance between the nearest and the furthest objects that are in acceptably sharp focus in an image captured with a camera.
For cameras that can only focus on one object distance at a time, depth of field is the distance between the nearest and the farthest objects that are in acceptably sharp focus in the image. "Acceptably sharp focus" is defined using a property called the "circle of confusion".
The depth of field can be determined by focal length, distance to subject (object to be imaged), the acceptable circle of confusion size, and aperture. Limitations of depth of field can sometimes be overcome with various techniques and equipment. The approximate depth of field can be given by:
for a given maximum acceptable circle of confusion (c), focal length (f), f-number (N), and distance to subject (u).
As distance or the size of the acceptable circle of confusion increases, the depth of field increases; however, increasing the size of the aperture (i.e., reducing f-number) or increasing the focal length reduces the depth of field. Depth of field changes linearly with f-number and circle of confusion, but changes in proportion to the square of the distance to the subject and inversely in proportion to the square of the focal length. As a result, photos taken at extremely close range (i.e., so small u) have a proportionally much smaller depth of field.
Rearranging the DOF equation shows that it is the ratio between distance and focal length that affects DOF;
Note that the ratio u/f is equal to the transverse magnification MT which is the ratio of the lateral image size to the lateral subject size.
Image sensor size affects DOF in counterintuitive ways. Because the circle of confusion is directly tied to the sensor size, decreasing the size of the sensor while holding focal length and aperture constant will decrease the depth of field (by the crop factor). The resulting image however will have a different field of view. If the focal length is altered to maintain the field of view, the change in focal length will counter the decrease of DOF from the smaller sensor and increase the depth of field (also by the crop factor).
For a given subject framing and camera position, the DOF is controlled by the lens aperture diameter, which is usually specified as the f-number (the ratio of lens focal length to aperture diameter). Reducing the aperture diameter (increasing the f-number) increases the DOF because only the light travelling at shallower angles passes through the aperture so only cones of rays with shallower angles reach the image plane. In other words, the circles of confusion are reduced or increasing the DOF.
For a given size of the subject's image in the focal plane, the same f-number on any focal length lens will give the same depth of field. This is evident from the above DOF equation by noting that the ratio u/f is constant for constant image size. For example, if the focal length is doubled, the subject distance is also doubled to keep the subject image size the same. This observation contrasts with the common notion that "focal length is twice as important to defocus as f/stop", which applies to a constant subject distance, as opposed to constant image size.
Motion pictures make limited use of aperture control; to produce a consistent image quality from shot to shot, cinematographers usually choose a single aperture setting for interiors (e.g., scenes inside a building) and another for exteriors (e.g., scenes in an area outside a building), and adjust exposure through the use of camera filters or light levels. Aperture settings are adjusted more frequently in still photography, where variations in depth of field are used to produce a variety of special effects.
Precise focus is only possible at an exact distance from a lens; at that distance, a point object will produce a small spot image. Otherwise, a point object will produce a larger or blur spot image that is typically and approximately a circle. When this circular spot is sufficiently small, it is visually indistinguishable from a point, and appears to be in focus. The diameter of the largest circle that is indistinguishable from a point is known as the acceptable circle of confusion, or informally, simply as the circle of confusion.
The acceptable circle of confusion depends on how the final image will be used. The circle of confusion as 0.25 mm for an image viewed from 25 cm away is generally accepted.
For 35 mm motion pictures, the image area on the film is roughly 22 mm by 16 mm. The limit of tolerable error was traditionally set at 0.05 mm (0.0020 in) diameter, while for 16 mm film, where the size is about half as large, the tolerance is stricter, 0.025 mm (0.00098 in). More modern practice for 35 mm productions set the circle of confusion limit at 0.025 mm (0.00098 in).
The term "camera movements" refers to swivel (swing and tilt, in modern terminology) and shift adjustments of the lens holder and the film holder. These features have been in use since the 1800s and are still in use today on view cameras, technical cameras, cameras with tilt/shift or perspective control lenses, etc. Swiveling the lens or sensor causes the plane of focus (POF) to swivel, and also causes the field of acceptable focus to swivel with the POF; and depending on the DOF criteria, to also change the shape of the field of acceptable focus. While calculations for DOF of cameras with swivel set to zero have been discussed, formulated, and documented since before the 1940s, documenting calculations for cameras with non-zero swivel seem to have begun in 1990.
More so than in the case of the zero swivel camera, there are various methods to form criteria and set up calculations for DOF when swivel is non-zero. There is a gradual reduction of clarity in objects as they move away from the POF, and at some virtual flat or curved surface the reduced clarity becomes unacceptable. Some photographers do calculations or use tables, some use markings on their equipment, some judge by previewing the image.
When the POF is rotated, the near and far limits of DOF may be thought of as wedge-shaped, with the apex of the wedge nearest the camera; or they may be thought of as parallel to the POF.
Traditional depth-of-field formulas can be hard to use in practice. As an alternative, the same effective calculation can be done without regard to the focal length and f-number. Moritz von Rohr and later Merklinger observe that the effective absolute aperture diameter can be used for similar formula in certain circumstances.
Moreover, traditional depth-of-field formulas assume equal acceptable circles of confusion for near and far objects. Merklinger suggested that distant objects often need to be much sharper to be clearly recognizable, whereas closer objects, being larger on the film, do not need to be so sharp. The loss of detail in distant objects may be particularly noticeable with extreme enlargements. Achieving this additional sharpness in distant objects usually requires focusing beyond the hyperfocal distance, sometimes almost at infinity. For example, if photographing a cityscape with a traffic bollard in the foreground, this approach, termed the object field method by Merklinger, would recommend focusing very close to infinity, and stopping down to make the bollard sharp enough. With this approach, foreground objects cannot always be made perfectly sharp, but the loss of sharpness in near objects may be acceptable if recognizability of distant objects is paramount.
Other authors such as Ansel Adams have taken the opposite position, maintaining that slight unsharpness in foreground objects is usually more disturbing than slight unsharpness in distant parts of a scene.
Some methods and equipment allow altering the apparent DOF, and some even allow the DOF to be determined after the image is made. These are based or supported by computational imaging processes. For example, focus stacking combines multiple images focused on different planes, resulting in an image with a greater (or less, if so desired) apparent depth of field than any of the individual source images. Similarly, in order to reconstruct the 3-dimensional shape of an object, a depth map can be generated from multiple photographs with different depths of field. Xiong and Shafer concluded, in part, "...the improvements on precisions of focus ranging and defocus ranging can lead to efficient shape recovery methods."
Another approach is focus sweep. The focal plane is swept across the entire relevant range during a single exposure. This creates a blurred image, but with a convolution kernel that is nearly independent of object depth, so that the blur is almost entirely removed after computational deconvolution. This has the added benefit of dramatically reducing motion blur.
Other technologies use a combination of lens design and post-processing: Wavefront coding is a method by which controlled aberrations are added to the optical system so that the focus and depth of field can be improved later in the process.
The lens design can be changed even more: in colour apodization the lens is modified such that each colour channel has a different lens aperture. For example, the red channel may be f/2.4, green may be f/2.4, whilst the blue channel may be f/5.6. Therefore, the blue channel will have a greater depth of field than the other colours. The image processing identifies blurred regions in the red and green channels and in these regions copies the sharper edge data from the blue channel. The result is an image that combines the best features from the different f-numbers.
At the extreme, a plenoptic camera captures 4D light field information about a scene, so the focus and depth of field can be altered after the photo is taken.
Diffraction causes images to lose sharpness at high F-numbers (i.e., narrow aperture stop opening sizes), and hence limits the potential depth of field. (This effect is not considered in the above formula giving approximate DOF values.) In general photography this is rarely an issue; because large f-numbers typically require long exposure times to acquire acceptable image brightness, motion blur may cause greater loss of sharpness than the loss from diffraction. However, diffraction is a greater issue in close-up photography, and the overall image sharpness can be degraded as photographers are trying to maximize depth of field with very small apertures.
Hansma and Peterson have discussed determining the combined effects of defocus and diffraction using a root-square combination of the individual blur spots. Hansma's approach determines the f-number that will give the maximum possible sharpness; Peterson's approach determines the minimum f-number that will give the desired sharpness in the final image and yields a maximum depth of field for which the desired sharpness can be achieved. In combination, the two methods can be regarded as giving a maximum and minimum f-number for a given situation, with the photographer free to choose any value within the range, as conditions (e.g., potential motion blur) permit. Gibson gives a similar discussion, additionally considering blurring effects of camera lens aberrations, enlarging lens diffraction and aberrations, the negative emulsion, and the printing paper. Couzin gave a formula essentially the same as Hansma's for optimal f-number, but did not discuss its derivation.
Hopkins, Stokseth, and Williams and Becklund have discussed the combined effects using the modulation transfer function.
Many lenses include scales that indicate the DOF for a given focus distance and f-number; the 35 mm lens in the image is typical. That lens includes distance scales in feet and meters; when a marked distance is set opposite the large white index mark, the focus is set to that distance. The DOF scale below the distance scales includes markings on either side of the index that correspond to f-numbers. When the lens is set to a given f-number, the DOF extends between the distances that align with the f-number markings.
Photographers can use the lens scales to work backwards from the desired depth of field to find the necessary focus distance and aperture. For the 35 mm lens shown, if it were desired for the DOF to extend from 1 m to 2 m, focus would be set so that index mark was centered between the marks for those distances, and the aperture would be set to f/11.
On a view camera, the focus and f-number can be obtained by measuring the depth of field and performing simple calculations. Some view cameras include DOF calculators that indicate focus and f-number without the need for any calculations by the photographer.
In optics and photography, hyperfocal distance is a distance beyond which all objects can be brought into an "acceptable" focus. As the hyperfocal distance is the focus distance giving the maximum depth of field, it is the most desirable distance to set the focus of a fixed-focus camera. The hyperfocal distance is entirely dependent upon what level of sharpness is considered to be acceptable.
The hyperfocal distance has a property called "consecutive depths of field", where a lens focused at an object whose distance is at the hyperfocal distance H will hold a depth of field from H/2 to infinity, if the lens is focused to H/2, the depth of field will extend from H/3 to H; if the lens is then focused to H/3, the depth of field will extend from H/4 to H/2, etc.
Thomas Sutton and George Dawson first wrote about hyperfocal distance (or "focal range") in 1867. Louis Derr in 1906 may have been the first to derive a formula for hyperfocal distance. Rudolf Kingslake wrote in 1951 about the two methods of measuring hyperfocal distance.
The DOF beyond the subject is always greater than the DOF in front of the subject. When the subject is at the hyperfocal distance or beyond, the far DOF is infinite, so the ratio is 1:∞; as the subject distance decreases, near:far DOF ratio increases, approaching unity at high magnification. For large apertures at typical portrait distances, the ratio is still close to 1:1.
This section covers some additional formula for evaluating depth of field; however they are all subject to significant simplifying assumptions: for example, they assume the paraxial approximation of Gaussian optics. They are suitable for practical photography, lens designers would use significantly more complex ones.
For given near and far DOF limits D N {\displaystyle D_{\mathrm {N} }} and D F {\displaystyle D_{\mathrm {F} }} , the required f-number is smallest when focus is set to
the harmonic mean of the near and far distances. In practice, this is equivalent to the arithmetic mean for shallow depths of field. Sometimes, view camera users refer to the difference v N − v F {\displaystyle v_{\mathrm {N} }-v_{\mathrm {F} }} as the focus spread.
If a subject is at distance s {\displaystyle s} and the foreground or background is at distance D {\displaystyle D} , let the distance between the subject and the foreground or background be indicated by
The blur disk diameter b {\displaystyle b} of a detail at distance x d {\displaystyle x_{\mathrm {d} }} from the subject can be expressed as a function of the subject magnification m s {\displaystyle m_{\mathrm {s} }} , focal length f {\displaystyle f} , f-number N {\displaystyle N} , or alternatively the aperture d {\displaystyle d} , according to
The minus sign applies to a foreground object, and the plus sign applies to a background object.
The blur increases with the distance from the subject; when b {\displaystyle b} is less than the circle of confusion, the detail is within the depth of field. | [
{
"paragraph_id": 0,
"text": "The depth of field (DOF) is the distance between the nearest and the furthest objects that are in acceptably sharp focus in an image captured with a camera.",
"title": ""
},
{
"paragraph_id": 1,
"text": "For cameras that can only focus on one object distance at a time, depth of field is the distance between the nearest and the farthest objects that are in acceptably sharp focus in the image. \"Acceptably sharp focus\" is defined using a property called the \"circle of confusion\".",
"title": "Factors affecting depth of field"
},
{
"paragraph_id": 2,
"text": "The depth of field can be determined by focal length, distance to subject (object to be imaged), the acceptable circle of confusion size, and aperture. Limitations of depth of field can sometimes be overcome with various techniques and equipment. The approximate depth of field can be given by:",
"title": "Factors affecting depth of field"
},
{
"paragraph_id": 3,
"text": "for a given maximum acceptable circle of confusion (c), focal length (f), f-number (N), and distance to subject (u).",
"title": "Factors affecting depth of field"
},
{
"paragraph_id": 4,
"text": "As distance or the size of the acceptable circle of confusion increases, the depth of field increases; however, increasing the size of the aperture (i.e., reducing f-number) or increasing the focal length reduces the depth of field. Depth of field changes linearly with f-number and circle of confusion, but changes in proportion to the square of the distance to the subject and inversely in proportion to the square of the focal length. As a result, photos taken at extremely close range (i.e., so small u) have a proportionally much smaller depth of field.",
"title": "Factors affecting depth of field"
},
{
"paragraph_id": 5,
"text": "Rearranging the DOF equation shows that it is the ratio between distance and focal length that affects DOF;",
"title": "Factors affecting depth of field"
},
{
"paragraph_id": 6,
"text": "Note that the ratio u/f is equal to the transverse magnification MT which is the ratio of the lateral image size to the lateral subject size.",
"title": "Factors affecting depth of field"
},
{
"paragraph_id": 7,
"text": "Image sensor size affects DOF in counterintuitive ways. Because the circle of confusion is directly tied to the sensor size, decreasing the size of the sensor while holding focal length and aperture constant will decrease the depth of field (by the crop factor). The resulting image however will have a different field of view. If the focal length is altered to maintain the field of view, the change in focal length will counter the decrease of DOF from the smaller sensor and increase the depth of field (also by the crop factor).",
"title": "Factors affecting depth of field"
},
{
"paragraph_id": 8,
"text": "For a given subject framing and camera position, the DOF is controlled by the lens aperture diameter, which is usually specified as the f-number (the ratio of lens focal length to aperture diameter). Reducing the aperture diameter (increasing the f-number) increases the DOF because only the light travelling at shallower angles passes through the aperture so only cones of rays with shallower angles reach the image plane. In other words, the circles of confusion are reduced or increasing the DOF.",
"title": "Factors affecting depth of field"
},
{
"paragraph_id": 9,
"text": "For a given size of the subject's image in the focal plane, the same f-number on any focal length lens will give the same depth of field. This is evident from the above DOF equation by noting that the ratio u/f is constant for constant image size. For example, if the focal length is doubled, the subject distance is also doubled to keep the subject image size the same. This observation contrasts with the common notion that \"focal length is twice as important to defocus as f/stop\", which applies to a constant subject distance, as opposed to constant image size.",
"title": "Factors affecting depth of field"
},
{
"paragraph_id": 10,
"text": "Motion pictures make limited use of aperture control; to produce a consistent image quality from shot to shot, cinematographers usually choose a single aperture setting for interiors (e.g., scenes inside a building) and another for exteriors (e.g., scenes in an area outside a building), and adjust exposure through the use of camera filters or light levels. Aperture settings are adjusted more frequently in still photography, where variations in depth of field are used to produce a variety of special effects.",
"title": "Factors affecting depth of field"
},
{
"paragraph_id": 11,
"text": "Precise focus is only possible at an exact distance from a lens; at that distance, a point object will produce a small spot image. Otherwise, a point object will produce a larger or blur spot image that is typically and approximately a circle. When this circular spot is sufficiently small, it is visually indistinguishable from a point, and appears to be in focus. The diameter of the largest circle that is indistinguishable from a point is known as the acceptable circle of confusion, or informally, simply as the circle of confusion.",
"title": "Factors affecting depth of field"
},
{
"paragraph_id": 12,
"text": "The acceptable circle of confusion depends on how the final image will be used. The circle of confusion as 0.25 mm for an image viewed from 25 cm away is generally accepted.",
"title": "Factors affecting depth of field"
},
{
"paragraph_id": 13,
"text": "For 35 mm motion pictures, the image area on the film is roughly 22 mm by 16 mm. The limit of tolerable error was traditionally set at 0.05 mm (0.0020 in) diameter, while for 16 mm film, where the size is about half as large, the tolerance is stricter, 0.025 mm (0.00098 in). More modern practice for 35 mm productions set the circle of confusion limit at 0.025 mm (0.00098 in).",
"title": "Factors affecting depth of field"
},
{
"paragraph_id": 14,
"text": "The term \"camera movements\" refers to swivel (swing and tilt, in modern terminology) and shift adjustments of the lens holder and the film holder. These features have been in use since the 1800s and are still in use today on view cameras, technical cameras, cameras with tilt/shift or perspective control lenses, etc. Swiveling the lens or sensor causes the plane of focus (POF) to swivel, and also causes the field of acceptable focus to swivel with the POF; and depending on the DOF criteria, to also change the shape of the field of acceptable focus. While calculations for DOF of cameras with swivel set to zero have been discussed, formulated, and documented since before the 1940s, documenting calculations for cameras with non-zero swivel seem to have begun in 1990.",
"title": "Factors affecting depth of field"
},
{
"paragraph_id": 15,
"text": "More so than in the case of the zero swivel camera, there are various methods to form criteria and set up calculations for DOF when swivel is non-zero. There is a gradual reduction of clarity in objects as they move away from the POF, and at some virtual flat or curved surface the reduced clarity becomes unacceptable. Some photographers do calculations or use tables, some use markings on their equipment, some judge by previewing the image.",
"title": "Factors affecting depth of field"
},
{
"paragraph_id": 16,
"text": "When the POF is rotated, the near and far limits of DOF may be thought of as wedge-shaped, with the apex of the wedge nearest the camera; or they may be thought of as parallel to the POF.",
"title": "Factors affecting depth of field"
},
{
"paragraph_id": 17,
"text": "Traditional depth-of-field formulas can be hard to use in practice. As an alternative, the same effective calculation can be done without regard to the focal length and f-number. Moritz von Rohr and later Merklinger observe that the effective absolute aperture diameter can be used for similar formula in certain circumstances.",
"title": "Object-field calculation methods"
},
{
"paragraph_id": 18,
"text": "Moreover, traditional depth-of-field formulas assume equal acceptable circles of confusion for near and far objects. Merklinger suggested that distant objects often need to be much sharper to be clearly recognizable, whereas closer objects, being larger on the film, do not need to be so sharp. The loss of detail in distant objects may be particularly noticeable with extreme enlargements. Achieving this additional sharpness in distant objects usually requires focusing beyond the hyperfocal distance, sometimes almost at infinity. For example, if photographing a cityscape with a traffic bollard in the foreground, this approach, termed the object field method by Merklinger, would recommend focusing very close to infinity, and stopping down to make the bollard sharp enough. With this approach, foreground objects cannot always be made perfectly sharp, but the loss of sharpness in near objects may be acceptable if recognizability of distant objects is paramount.",
"title": "Object-field calculation methods"
},
{
"paragraph_id": 19,
"text": "Other authors such as Ansel Adams have taken the opposite position, maintaining that slight unsharpness in foreground objects is usually more disturbing than slight unsharpness in distant parts of a scene.",
"title": "Object-field calculation methods"
},
{
"paragraph_id": 20,
"text": "Some methods and equipment allow altering the apparent DOF, and some even allow the DOF to be determined after the image is made. These are based or supported by computational imaging processes. For example, focus stacking combines multiple images focused on different planes, resulting in an image with a greater (or less, if so desired) apparent depth of field than any of the individual source images. Similarly, in order to reconstruct the 3-dimensional shape of an object, a depth map can be generated from multiple photographs with different depths of field. Xiong and Shafer concluded, in part, \"...the improvements on precisions of focus ranging and defocus ranging can lead to efficient shape recovery methods.\"",
"title": "Overcoming DOF limitations"
},
{
"paragraph_id": 21,
"text": "Another approach is focus sweep. The focal plane is swept across the entire relevant range during a single exposure. This creates a blurred image, but with a convolution kernel that is nearly independent of object depth, so that the blur is almost entirely removed after computational deconvolution. This has the added benefit of dramatically reducing motion blur.",
"title": "Overcoming DOF limitations"
},
{
"paragraph_id": 22,
"text": "Other technologies use a combination of lens design and post-processing: Wavefront coding is a method by which controlled aberrations are added to the optical system so that the focus and depth of field can be improved later in the process.",
"title": "Overcoming DOF limitations"
},
{
"paragraph_id": 23,
"text": "The lens design can be changed even more: in colour apodization the lens is modified such that each colour channel has a different lens aperture. For example, the red channel may be f/2.4, green may be f/2.4, whilst the blue channel may be f/5.6. Therefore, the blue channel will have a greater depth of field than the other colours. The image processing identifies blurred regions in the red and green channels and in these regions copies the sharper edge data from the blue channel. The result is an image that combines the best features from the different f-numbers.",
"title": "Overcoming DOF limitations"
},
{
"paragraph_id": 24,
"text": "At the extreme, a plenoptic camera captures 4D light field information about a scene, so the focus and depth of field can be altered after the photo is taken.",
"title": "Overcoming DOF limitations"
},
{
"paragraph_id": 25,
"text": "Diffraction causes images to lose sharpness at high F-numbers (i.e., narrow aperture stop opening sizes), and hence limits the potential depth of field. (This effect is not considered in the above formula giving approximate DOF values.) In general photography this is rarely an issue; because large f-numbers typically require long exposure times to acquire acceptable image brightness, motion blur may cause greater loss of sharpness than the loss from diffraction. However, diffraction is a greater issue in close-up photography, and the overall image sharpness can be degraded as photographers are trying to maximize depth of field with very small apertures.",
"title": "Diffraction and DOF"
},
{
"paragraph_id": 26,
"text": "Hansma and Peterson have discussed determining the combined effects of defocus and diffraction using a root-square combination of the individual blur spots. Hansma's approach determines the f-number that will give the maximum possible sharpness; Peterson's approach determines the minimum f-number that will give the desired sharpness in the final image and yields a maximum depth of field for which the desired sharpness can be achieved. In combination, the two methods can be regarded as giving a maximum and minimum f-number for a given situation, with the photographer free to choose any value within the range, as conditions (e.g., potential motion blur) permit. Gibson gives a similar discussion, additionally considering blurring effects of camera lens aberrations, enlarging lens diffraction and aberrations, the negative emulsion, and the printing paper. Couzin gave a formula essentially the same as Hansma's for optimal f-number, but did not discuss its derivation.",
"title": "Diffraction and DOF"
},
{
"paragraph_id": 27,
"text": "Hopkins, Stokseth, and Williams and Becklund have discussed the combined effects using the modulation transfer function.",
"title": "Diffraction and DOF"
},
{
"paragraph_id": 28,
"text": "Many lenses include scales that indicate the DOF for a given focus distance and f-number; the 35 mm lens in the image is typical. That lens includes distance scales in feet and meters; when a marked distance is set opposite the large white index mark, the focus is set to that distance. The DOF scale below the distance scales includes markings on either side of the index that correspond to f-numbers. When the lens is set to a given f-number, the DOF extends between the distances that align with the f-number markings.",
"title": "DOF scales"
},
{
"paragraph_id": 29,
"text": "Photographers can use the lens scales to work backwards from the desired depth of field to find the necessary focus distance and aperture. For the 35 mm lens shown, if it were desired for the DOF to extend from 1 m to 2 m, focus would be set so that index mark was centered between the marks for those distances, and the aperture would be set to f/11.",
"title": "DOF scales"
},
{
"paragraph_id": 30,
"text": "On a view camera, the focus and f-number can be obtained by measuring the depth of field and performing simple calculations. Some view cameras include DOF calculators that indicate focus and f-number without the need for any calculations by the photographer.",
"title": "DOF scales"
},
{
"paragraph_id": 31,
"text": "In optics and photography, hyperfocal distance is a distance beyond which all objects can be brought into an \"acceptable\" focus. As the hyperfocal distance is the focus distance giving the maximum depth of field, it is the most desirable distance to set the focus of a fixed-focus camera. The hyperfocal distance is entirely dependent upon what level of sharpness is considered to be acceptable.",
"title": "Hyperfocal distance"
},
{
"paragraph_id": 32,
"text": "The hyperfocal distance has a property called \"consecutive depths of field\", where a lens focused at an object whose distance is at the hyperfocal distance H will hold a depth of field from H/2 to infinity, if the lens is focused to H/2, the depth of field will extend from H/3 to H; if the lens is then focused to H/3, the depth of field will extend from H/4 to H/2, etc.",
"title": "Hyperfocal distance"
},
{
"paragraph_id": 33,
"text": "Thomas Sutton and George Dawson first wrote about hyperfocal distance (or \"focal range\") in 1867. Louis Derr in 1906 may have been the first to derive a formula for hyperfocal distance. Rudolf Kingslake wrote in 1951 about the two methods of measuring hyperfocal distance.",
"title": "Hyperfocal distance"
},
{
"paragraph_id": 34,
"text": "The DOF beyond the subject is always greater than the DOF in front of the subject. When the subject is at the hyperfocal distance or beyond, the far DOF is infinite, so the ratio is 1:∞; as the subject distance decreases, near:far DOF ratio increases, approaching unity at high magnification. For large apertures at typical portrait distances, the ratio is still close to 1:1.",
"title": "Near:far distribution"
},
{
"paragraph_id": 35,
"text": "This section covers some additional formula for evaluating depth of field; however they are all subject to significant simplifying assumptions: for example, they assume the paraxial approximation of Gaussian optics. They are suitable for practical photography, lens designers would use significantly more complex ones.",
"title": "DOF formulae"
},
{
"paragraph_id": 36,
"text": "For given near and far DOF limits D N {\\displaystyle D_{\\mathrm {N} }} and D F {\\displaystyle D_{\\mathrm {F} }} , the required f-number is smallest when focus is set to",
"title": "DOF formulae"
},
{
"paragraph_id": 37,
"text": "the harmonic mean of the near and far distances. In practice, this is equivalent to the arithmetic mean for shallow depths of field. Sometimes, view camera users refer to the difference v N − v F {\\displaystyle v_{\\mathrm {N} }-v_{\\mathrm {F} }} as the focus spread.",
"title": "DOF formulae"
},
{
"paragraph_id": 38,
"text": "If a subject is at distance s {\\displaystyle s} and the foreground or background is at distance D {\\displaystyle D} , let the distance between the subject and the foreground or background be indicated by",
"title": "DOF formulae"
},
{
"paragraph_id": 39,
"text": "The blur disk diameter b {\\displaystyle b} of a detail at distance x d {\\displaystyle x_{\\mathrm {d} }} from the subject can be expressed as a function of the subject magnification m s {\\displaystyle m_{\\mathrm {s} }} , focal length f {\\displaystyle f} , f-number N {\\displaystyle N} , or alternatively the aperture d {\\displaystyle d} , according to",
"title": "DOF formulae"
},
{
"paragraph_id": 40,
"text": "The minus sign applies to a foreground object, and the plus sign applies to a background object.",
"title": "DOF formulae"
},
{
"paragraph_id": 41,
"text": "The blur increases with the distance from the subject; when b {\\displaystyle b} is less than the circle of confusion, the detail is within the depth of field.",
"title": "DOF formulae"
}
] | The depth of field (DOF) is the distance between the nearest and the furthest objects that are in acceptably sharp focus in an image captured with a camera. | 2001-09-06T20:20:37Z | 2023-12-11T23:20:22Z | [
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8,368 | Dumnonii | The Dumnonii or Dumnones were a British tribe who inhabited Dumnonia, the area now known as Cornwall and Devon (and some areas of present-day Dorset and Somerset) in the further parts of the South West peninsula of Britain, from at least the Iron Age up to the early Saxon period. They were bordered to the east by the Durotriges tribe.
William Camden, in his 1607 edition of Britannia, describes Cornwall and Devon as being two parts of the same 'country' which:
was in ancient time inhabited by those Britains whom Solinus called Dunmonii, Ptolomee Damnonii, or (as we find in some other copies) more truly Danmonii. ... . But... the Country of this nation is at this day divided into two parts, known by later names of Cornwall and Denshire [Devonshire] ... The near or hithermore region of the Danmonians that I spake of is now commonly called Denshire, [or] by the Cornish-Britains 'Dewnan', and by the Welsh Britains 'Duffneint' [sic], that is, 'low valleys', for that the people dwell for the most part beneath in Vales; by the English Saxons [it is known as] 'Deven-schire', whereof grew the Latin name 'Devonia', and by that contraction which the vulgar people useth, 'Denshire'.
Camden had learnt some Welsh during the course of his studies and it would appear that he is the origin of the interpretation of Dumnonii as "deep valley dwellers" from his understanding of the Welsh of his time. The modern Welsh term is Dyfnaint. John Rhŷs later theorized that the tribal name was derived from the name of a goddess, Domnu, probably meaning "the goddess of the deep". The proto-Celtic root *dubno- or *dumno- meaning "the deep" or "the earth" (or alternatively meaning "dark" or "gloomy") appears in personal names such as Dumnorix and Dubnovellaunus. Another group with a similar name but with no known links were the Fir Domnann of Connacht.
The Roman name of the town of Exeter, Isca Dumnoniorum ("Isca of the Dumnonii"), contains the root *iska- "water" for "Water of the Dumnonii". The Latin name suggests that the city was already an oppidum, or walled town, on the banks on the River Exe before the foundation of the Roman city, in about AD 50. The Dumnonii gave their name to the English county of Devon, and their name is represented in Britain's two extant Brythonic languages as Dewnans in Cornish and Dyfnaint in Welsh. Amédée Thierry (Histoire des Gaulois, 1828), one of the inventors of the "historic race" of Gauls, could confidently equate them with the Cornish ("les Cornouailles").
Victorian historians often referred to the tribe as the Damnonii, which is also the name of another people from lowland Scotland, although there are no known links between the two populations.
The people of Dumnonia spoke a Southwestern Brythonic dialect of Celtic similar to the forerunner of more recent Cornish and Breton. Irish immigrants, the Déisi, are evidenced by the Ogham-inscribed stones they have left behind, confirmed and supplemented by toponymical studies. The stones are sometimes inscribed in Latin, sometimes in both scripts. Tristram Risdon suggested the continuance of a Brythonic dialect in the South Hams, Devon, as late as the 14th century, in addition to its use in Cornwall.
Ptolemy's 2nd century Geography places the Dumnonii to the west of the Durotriges. The name purocoronavium that appears in the Ravenna Cosmography implies the existence of a sub-tribe called the Cornavii or Cornovii, perhaps the ancestors of the Cornish people.
Gaius Iulius Solinus, probably in the 3rd century, remarks: "This turbid strait also divides the island Silura from the shore which is held by the Dumnonii, a British tribe. The men of this island even now preserve an old custom: they do not use coins. They give and accept, obtaining the necessities of life by exchange rather than by money. They reverence gods, and the men and women equally declare knowledge of the future."
In the sub-Roman period a Brythonic kingdom called Dumnonia emerged, covering the entire peninsula, although it is believed by some to have effectively been a collection of sub-kingdoms.
A kingdom of Domnonée (and of Cornouaille alongside) was established in the province of Armorica directly across the English Channel, and has apparent links with the British population, suggesting an ancient connection of peoples along the western Atlantic seaboard.
The Latin name for Exeter is Isca Dumnoniorum ("Water of the Dumnonii"). This oppidum (a Latin term meaning an important town) on the banks of River Exe certainly existed prior to the foundation of the Roman city in about AD 50. Isca is derived from the Brythonic word for flowing water, which was given to the River Exe. The Gaelic term for water is uisce/uisge. This is reflected in the Welsh name for Exeter: Caerwysg meaning "fortified settlement on the river Uisc".
Isca Dumnoniorum originated with a settlement that developed around the Roman fortress of the Legio II Augusta and is one of the four poleis (cities) attributed to the tribe by Ptolemy. It is also listed in two routes of the late 2nd century Antonine Itinerary.
A legionary bath-house was built inside the fortress sometime between 55 and 60 and underwent renovation shortly afterwards (c. 60-65) but by c. 68 (perhaps even 66) the legion had transferred to a newer fortress at Gloucester. This saw the dismantling of the Isca fortress, and the site was then abandoned. Around AD 75, work on the civitas forum and basilica had commenced on the site of the former principia and by the late 2nd century the civitas walls had been completed. They were 3 metres thick and 6 metres high and enclosed exactly the same area as the earlier fortress. However, by the late 4th century the civitas was in decline.
Next to these [the Durotriges], but more to the west, are the Dumnoni, whose towns are:Voliba 14°45 52°00Uxella 15°00 52°45Tamara 15°00 52°15Isca, where is located Legio II Augusta 17°30 52°45.
—Ptolemy, Geography II.ii.
As well as Isca Dumnoniorum, Ptolemy's 2nd century Geography names three other towns:
The Ravenna Cosmography includes the last two names (in slightly different forms, as "Tamaris" and "Uxelis"), and adds several more names which may be settlements in the territory. These include:
Other Romano-British sites in Dumnonia include:
New settlements continued to be built throughout the Roman period, including sites at Chysauster and Trevelgue Head. The style is native in form with no Romanised features. Near Padstow, a site of some importance that was inhabited from the late Bronze/early Iron Age to the mid 6th century now lies buried under the sands on the opposite side of the Camel estuary near St. Enodoc's Church, and may have been a western coastal equivalent of a Saxon Shore Fort. Byzantine and African pottery has been discovered at the site. At Magor Farm in Illogan, near Camborne, an archaeological site has been identified as being a villa.
The Dumnonii are thought to have occupied relatively isolated territory in Cornwall, Devon, Somerset and possibly part of Dorset. Their cultural connections, as expressed in their ceramics, were with the peninsula of Armorica across the Channel, rather than with the southeast of Britain. They do not seem to have been politically centralised: coins are relatively rare, none of them locally minted, and the structure, distribution and construction of Bronze Age and Iron Age hill forts, Cornish rounds, and defensible farmsteads in the south west point to a number of smaller tribal groups living alongside each other.
Dumnonia is noteworthy for its many settlements that have survived from the Romano-British period, but also for its lack of a villa system. Local archaeology has revealed instead the isolated enclosed farmsteads known locally as rounds. These seem to have survived the Roman abandonment of Britain, but were subsequently replaced, in the 6th and 7th centuries, by the unenclosed farms taking the Brythonic toponymic tre-.
As in most other Brythonic areas, Iron Age hill forts, such as Hembury Castle, were refortified for the use of chieftains or kings. Other high-status settlements such as Tintagel seem to have been reconstructed during this period. Post-Roman imported pottery has been excavated from many sites across the region, and the apparent surge in late 5th century Mediterranean and/or Byzantine imports is yet to be explained satisfactorily.
Apart from fishing and agriculture, the main economic resource of the Dumnonii was tin mining. The area of Dumnonia had been mined since ancient times, and the tin was exported from the ancient trading port of Ictis (St Michael's Mount). Tin extraction (mainly by streaming) had existed here from the early Bronze Age around the 22nd century BC. West Cornwall, around Mount's Bay, was traditionally thought to have been visited by metal traders from the eastern Mediterranean
During the first millennium BC trade became more organised, first with the Phoenicians, who settled Gades (Cadiz) around 1100 BC, and later with the Greeks, who had settled Massilia (Marseilles) and Narbo (Narbonne) around 600 BC. Smelted Cornish tin was collected at Ictis whence it was conveyed across the Bay of Biscay to the mouth of the Loire and then to Gades via the Loire and Rhone valleys. It went then through the Mediterranean Sea in ships to Gades.
During the period c. 500-450 BC, the tin deposits seem to have become more important, and fortified settlements appear such as at Chun Castle and Kenidjack Castle, to protect both the tin smelters and mines.
The earliest account of Cornish tin mining was written by Pytheas of Massilia late in the 4th century BC after his circumnavigation of the British Isles. Underground mining was described in this account, although it cannot be determined when it had started. Pytheas's account was noted later by other writers including Pliny the Elder and Diodorus Siculus.
It is likely that tin trade with the Mediterranean was later on under the control of the Veneti. Britain was one of the places proposed for the Cassiterides, that is Tin Islands. Tin working continued throughout Roman occupation although it appears that output declined because of new supplies brought in from the deposits discovered in Iberia (Spain and Portugal). However, when these supplies diminished, production in Dumnonia increased and appears to have reached a peak during the 3rd century AD.
The Sub-Roman or Post-Roman history of Dumnonia comes from a variety of sources and is considered exceedingly difficult to interpret given that historical fact, legend and confused pseudo-history are compounded by a variety of sources in Middle Welsh and Latin. The main sources available for discussion of this period include Gildas's De Excidio Britanniae and Nennius's Historia Brittonum, the Annales Cambriae, Anglo-Saxon Chronicle, William of Malmesbury's Gesta Regum Anglorum and De Antiquitate Glastoniensis Ecclesiae, along with texts from the Black Book of Carmarthen and the Red Book of Hergest, and Bede's Historia ecclesiastica gentis Anglorum as well as "The Descent of the Men of the North" (Bonedd Gwŷr y Gogledd, in Peniarth MS 45 and elsewhere) and the Book of Baglan. | [
{
"paragraph_id": 0,
"text": "The Dumnonii or Dumnones were a British tribe who inhabited Dumnonia, the area now known as Cornwall and Devon (and some areas of present-day Dorset and Somerset) in the further parts of the South West peninsula of Britain, from at least the Iron Age up to the early Saxon period. They were bordered to the east by the Durotriges tribe.",
"title": ""
},
{
"paragraph_id": 1,
"text": "William Camden, in his 1607 edition of Britannia, describes Cornwall and Devon as being two parts of the same 'country' which:",
"title": "Etymology"
},
{
"paragraph_id": 2,
"text": "was in ancient time inhabited by those Britains whom Solinus called Dunmonii, Ptolomee Damnonii, or (as we find in some other copies) more truly Danmonii. ... . But... the Country of this nation is at this day divided into two parts, known by later names of Cornwall and Denshire [Devonshire] ... The near or hithermore region of the Danmonians that I spake of is now commonly called Denshire, [or] by the Cornish-Britains 'Dewnan', and by the Welsh Britains 'Duffneint' [sic], that is, 'low valleys', for that the people dwell for the most part beneath in Vales; by the English Saxons [it is known as] 'Deven-schire', whereof grew the Latin name 'Devonia', and by that contraction which the vulgar people useth, 'Denshire'.",
"title": "Etymology"
},
{
"paragraph_id": 3,
"text": "Camden had learnt some Welsh during the course of his studies and it would appear that he is the origin of the interpretation of Dumnonii as \"deep valley dwellers\" from his understanding of the Welsh of his time. The modern Welsh term is Dyfnaint. John Rhŷs later theorized that the tribal name was derived from the name of a goddess, Domnu, probably meaning \"the goddess of the deep\". The proto-Celtic root *dubno- or *dumno- meaning \"the deep\" or \"the earth\" (or alternatively meaning \"dark\" or \"gloomy\") appears in personal names such as Dumnorix and Dubnovellaunus. Another group with a similar name but with no known links were the Fir Domnann of Connacht.",
"title": "Etymology"
},
{
"paragraph_id": 4,
"text": "The Roman name of the town of Exeter, Isca Dumnoniorum (\"Isca of the Dumnonii\"), contains the root *iska- \"water\" for \"Water of the Dumnonii\". The Latin name suggests that the city was already an oppidum, or walled town, on the banks on the River Exe before the foundation of the Roman city, in about AD 50. The Dumnonii gave their name to the English county of Devon, and their name is represented in Britain's two extant Brythonic languages as Dewnans in Cornish and Dyfnaint in Welsh. Amédée Thierry (Histoire des Gaulois, 1828), one of the inventors of the \"historic race\" of Gauls, could confidently equate them with the Cornish (\"les Cornouailles\").",
"title": "Etymology"
},
{
"paragraph_id": 5,
"text": "Victorian historians often referred to the tribe as the Damnonii, which is also the name of another people from lowland Scotland, although there are no known links between the two populations.",
"title": "Etymology"
},
{
"paragraph_id": 6,
"text": "The people of Dumnonia spoke a Southwestern Brythonic dialect of Celtic similar to the forerunner of more recent Cornish and Breton. Irish immigrants, the Déisi, are evidenced by the Ogham-inscribed stones they have left behind, confirmed and supplemented by toponymical studies. The stones are sometimes inscribed in Latin, sometimes in both scripts. Tristram Risdon suggested the continuance of a Brythonic dialect in the South Hams, Devon, as late as the 14th century, in addition to its use in Cornwall.",
"title": "Language"
},
{
"paragraph_id": 7,
"text": "Ptolemy's 2nd century Geography places the Dumnonii to the west of the Durotriges. The name purocoronavium that appears in the Ravenna Cosmography implies the existence of a sub-tribe called the Cornavii or Cornovii, perhaps the ancestors of the Cornish people.",
"title": "Territory"
},
{
"paragraph_id": 8,
"text": "Gaius Iulius Solinus, probably in the 3rd century, remarks: \"This turbid strait also divides the island Silura from the shore which is held by the Dumnonii, a British tribe. The men of this island even now preserve an old custom: they do not use coins. They give and accept, obtaining the necessities of life by exchange rather than by money. They reverence gods, and the men and women equally declare knowledge of the future.\"",
"title": "Territory"
},
{
"paragraph_id": 9,
"text": "In the sub-Roman period a Brythonic kingdom called Dumnonia emerged, covering the entire peninsula, although it is believed by some to have effectively been a collection of sub-kingdoms.",
"title": "Territory"
},
{
"paragraph_id": 10,
"text": "A kingdom of Domnonée (and of Cornouaille alongside) was established in the province of Armorica directly across the English Channel, and has apparent links with the British population, suggesting an ancient connection of peoples along the western Atlantic seaboard.",
"title": "Territory"
},
{
"paragraph_id": 11,
"text": "The Latin name for Exeter is Isca Dumnoniorum (\"Water of the Dumnonii\"). This oppidum (a Latin term meaning an important town) on the banks of River Exe certainly existed prior to the foundation of the Roman city in about AD 50. Isca is derived from the Brythonic word for flowing water, which was given to the River Exe. The Gaelic term for water is uisce/uisge. This is reflected in the Welsh name for Exeter: Caerwysg meaning \"fortified settlement on the river Uisc\".",
"title": "Settlements"
},
{
"paragraph_id": 12,
"text": "Isca Dumnoniorum originated with a settlement that developed around the Roman fortress of the Legio II Augusta and is one of the four poleis (cities) attributed to the tribe by Ptolemy. It is also listed in two routes of the late 2nd century Antonine Itinerary.",
"title": "Settlements"
},
{
"paragraph_id": 13,
"text": "A legionary bath-house was built inside the fortress sometime between 55 and 60 and underwent renovation shortly afterwards (c. 60-65) but by c. 68 (perhaps even 66) the legion had transferred to a newer fortress at Gloucester. This saw the dismantling of the Isca fortress, and the site was then abandoned. Around AD 75, work on the civitas forum and basilica had commenced on the site of the former principia and by the late 2nd century the civitas walls had been completed. They were 3 metres thick and 6 metres high and enclosed exactly the same area as the earlier fortress. However, by the late 4th century the civitas was in decline.",
"title": "Settlements"
},
{
"paragraph_id": 14,
"text": "Next to these [the Durotriges], but more to the west, are the Dumnoni, whose towns are:Voliba 14°45 52°00Uxella 15°00 52°45Tamara 15°00 52°15Isca, where is located Legio II Augusta 17°30 52°45.",
"title": "Settlements"
},
{
"paragraph_id": 15,
"text": "—Ptolemy, Geography II.ii.",
"title": "Settlements"
},
{
"paragraph_id": 16,
"text": "As well as Isca Dumnoniorum, Ptolemy's 2nd century Geography names three other towns:",
"title": "Settlements"
},
{
"paragraph_id": 17,
"text": "The Ravenna Cosmography includes the last two names (in slightly different forms, as \"Tamaris\" and \"Uxelis\"), and adds several more names which may be settlements in the territory. These include:",
"title": "Settlements"
},
{
"paragraph_id": 18,
"text": "Other Romano-British sites in Dumnonia include:",
"title": "Settlements"
},
{
"paragraph_id": 19,
"text": "New settlements continued to be built throughout the Roman period, including sites at Chysauster and Trevelgue Head. The style is native in form with no Romanised features. Near Padstow, a site of some importance that was inhabited from the late Bronze/early Iron Age to the mid 6th century now lies buried under the sands on the opposite side of the Camel estuary near St. Enodoc's Church, and may have been a western coastal equivalent of a Saxon Shore Fort. Byzantine and African pottery has been discovered at the site. At Magor Farm in Illogan, near Camborne, an archaeological site has been identified as being a villa.",
"title": "Settlements"
},
{
"paragraph_id": 20,
"text": "The Dumnonii are thought to have occupied relatively isolated territory in Cornwall, Devon, Somerset and possibly part of Dorset. Their cultural connections, as expressed in their ceramics, were with the peninsula of Armorica across the Channel, rather than with the southeast of Britain. They do not seem to have been politically centralised: coins are relatively rare, none of them locally minted, and the structure, distribution and construction of Bronze Age and Iron Age hill forts, Cornish rounds, and defensible farmsteads in the south west point to a number of smaller tribal groups living alongside each other.",
"title": "Archaeology"
},
{
"paragraph_id": 21,
"text": "Dumnonia is noteworthy for its many settlements that have survived from the Romano-British period, but also for its lack of a villa system. Local archaeology has revealed instead the isolated enclosed farmsteads known locally as rounds. These seem to have survived the Roman abandonment of Britain, but were subsequently replaced, in the 6th and 7th centuries, by the unenclosed farms taking the Brythonic toponymic tre-.",
"title": "Archaeology"
},
{
"paragraph_id": 22,
"text": "As in most other Brythonic areas, Iron Age hill forts, such as Hembury Castle, were refortified for the use of chieftains or kings. Other high-status settlements such as Tintagel seem to have been reconstructed during this period. Post-Roman imported pottery has been excavated from many sites across the region, and the apparent surge in late 5th century Mediterranean and/or Byzantine imports is yet to be explained satisfactorily.",
"title": "Archaeology"
},
{
"paragraph_id": 23,
"text": "Apart from fishing and agriculture, the main economic resource of the Dumnonii was tin mining. The area of Dumnonia had been mined since ancient times, and the tin was exported from the ancient trading port of Ictis (St Michael's Mount). Tin extraction (mainly by streaming) had existed here from the early Bronze Age around the 22nd century BC. West Cornwall, around Mount's Bay, was traditionally thought to have been visited by metal traders from the eastern Mediterranean",
"title": "Industries"
},
{
"paragraph_id": 24,
"text": "During the first millennium BC trade became more organised, first with the Phoenicians, who settled Gades (Cadiz) around 1100 BC, and later with the Greeks, who had settled Massilia (Marseilles) and Narbo (Narbonne) around 600 BC. Smelted Cornish tin was collected at Ictis whence it was conveyed across the Bay of Biscay to the mouth of the Loire and then to Gades via the Loire and Rhone valleys. It went then through the Mediterranean Sea in ships to Gades.",
"title": "Industries"
},
{
"paragraph_id": 25,
"text": "During the period c. 500-450 BC, the tin deposits seem to have become more important, and fortified settlements appear such as at Chun Castle and Kenidjack Castle, to protect both the tin smelters and mines.",
"title": "Industries"
},
{
"paragraph_id": 26,
"text": "The earliest account of Cornish tin mining was written by Pytheas of Massilia late in the 4th century BC after his circumnavigation of the British Isles. Underground mining was described in this account, although it cannot be determined when it had started. Pytheas's account was noted later by other writers including Pliny the Elder and Diodorus Siculus.",
"title": "Industries"
},
{
"paragraph_id": 27,
"text": "It is likely that tin trade with the Mediterranean was later on under the control of the Veneti. Britain was one of the places proposed for the Cassiterides, that is Tin Islands. Tin working continued throughout Roman occupation although it appears that output declined because of new supplies brought in from the deposits discovered in Iberia (Spain and Portugal). However, when these supplies diminished, production in Dumnonia increased and appears to have reached a peak during the 3rd century AD.",
"title": "Industries"
},
{
"paragraph_id": 28,
"text": "The Sub-Roman or Post-Roman history of Dumnonia comes from a variety of sources and is considered exceedingly difficult to interpret given that historical fact, legend and confused pseudo-history are compounded by a variety of sources in Middle Welsh and Latin. The main sources available for discussion of this period include Gildas's De Excidio Britanniae and Nennius's Historia Brittonum, the Annales Cambriae, Anglo-Saxon Chronicle, William of Malmesbury's Gesta Regum Anglorum and De Antiquitate Glastoniensis Ecclesiae, along with texts from the Black Book of Carmarthen and the Red Book of Hergest, and Bede's Historia ecclesiastica gentis Anglorum as well as \"The Descent of the Men of the North\" (Bonedd Gwŷr y Gogledd, in Peniarth MS 45 and elsewhere) and the Book of Baglan.",
"title": "Sub-Roman and post-Roman Dumnonia"
}
] | The Dumnonii or Dumnones were a British tribe who inhabited Dumnonia, the area now known as Cornwall and Devon in the further parts of the South West peninsula of Britain, from at least the Iron Age up to the early Saxon period. They were bordered to the east by the Durotriges tribe. | 2001-08-30T13:40:34Z | 2023-12-29T21:49:13Z | [
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8,372 | Declaration of independence | A declaration of independence, declaration of statehood or proclamation of independence is an assertion by a polity in a defined territory that it is independent and constitutes a state. Such places are usually declared from part or all of the territory of another state or failed state, or are breakaway territories from within the larger state. In 2010, the UN's International Court of Justice ruled in an advisory opinion in Kosovo that "International law contains no prohibition on declarations of independence", though the state from which the territory wishes to secede may regard the declaration as rebellion, which may lead to a war of independence or a constitutional settlement to resolve the crisis. | [
{
"paragraph_id": 0,
"text": "A declaration of independence, declaration of statehood or proclamation of independence is an assertion by a polity in a defined territory that it is independent and constitutes a state. Such places are usually declared from part or all of the territory of another state or failed state, or are breakaway territories from within the larger state. In 2010, the UN's International Court of Justice ruled in an advisory opinion in Kosovo that \"International law contains no prohibition on declarations of independence\", though the state from which the territory wishes to secede may regard the declaration as rebellion, which may lead to a war of independence or a constitutional settlement to resolve the crisis.",
"title": ""
}
] | A declaration of independence, declaration of statehood or proclamation of independence is an assertion by a polity in a defined territory that it is independent and constitutes a state. Such places are usually declared from part or all of the territory of another state or failed state, or are breakaway territories from within the larger state. In 2010, the UN's International Court of Justice ruled in an advisory opinion in Kosovo that "International law contains no prohibition on declarations of independence", though the state from which the territory wishes to secede may regard the declaration as rebellion, which may lead to a war of independence or a constitutional settlement to resolve the crisis. | 2001-08-31T03:47:27Z | 2023-12-24T02:31:48Z | [
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8,373 | Drag racing | Drag racing is a type of motor racing in which automobiles or motorcycles compete, usually two at a time, to be first to cross a set finish line. The race follows a short, straight course from a standing start over a measured distance, most commonly 1⁄4 mi (1,320 ft; 402 m), with a shorter, 1,000 ft (0.19 mi; 304.80 m) distance becoming increasingly popular, as it has become the standard for Top Fuel dragsters and Funny Cars, where some major bracket races and other sanctioning bodies have adopted it as the standard. The 1⁄8 mi (660 ft; 201 m) is also popular in some circles. Electronic timing and speed sensing systems have been used to record race results since the 1960s.
The history of automobiles and motorcycles being used for drag racing is nearly as long as the history of motorized vehicles themselves, and has taken the form of both illegal street racing and as a regulated motorsport.
Drag racing started in the 1940s. World War II veterans were prominently involved, and some early drag races were done at decommissioned aircraft bases with landing strips that made them an ideal place for the sport. In 1951, Wally Parks formed the National Hot Rod Association (NHRA). The organization banned the use of nitromethane in 1957, calling it unsafe, in part through the efforts of C. J. Hart; the ban would be lifted in 1963.
Several other racing organizations were created over the past several decades, such as the Professional Drag Racers Association (PDRA) founded in 2014.
Thanks, in part, to the Discovery series Street Outlaws, fandom for drag racing has seen a resurgence in the past decade.
Push starts to get engines running were necessary until the National Hot Rod Association (NHRA) mandated self-starters in 1976. After burnouts, cars would be pushed back by crews; this persisted until NHRA required reversing systems in 1980. Don Garlits was the first to do burnouts across the starting line, which is now standard practice. Each driver then backs up to and stages at the starting line.
Before each race (commonly known as a pass), each driver is allowed to perform a burnout, which heats the driving tires and lays rubber down at the beginning of the track, improving traction. The cars run through a "water box" (formerly a "bleach box", before bleach was replaced by flammable traction compound, which produced spectacular, and dangerous, flame burnouts; the hazard led NHRA to mandate use of water in the 1970s).
Modern races are started electronically by a system known as a Christmas tree, which consists of a column of lights for each driver/lane, and two light beam sensors per lane on the track at the starting line. Current NHRA trees, for example, feature one blue light (split into halves), then three amber, one green, and one red. When the first light beam is broken by a vehicle's front tire(s), the vehicle is "pre-staged" (approximately 7 inches (180 mm) from the starting line), and the pre-stage indicator on the tree is lit. When the second light beam is broken, the vehicle is "staged", and the stage indicator on the tree is lit. Vehicles may then leave the pre-stage beam, but must remain in the stage beam until the race starts.
Once one competitor is staged, their opponent has a set amount of time to stage or they will be instantly disqualified, indicated by a red light on the tree. Otherwise, once both drivers are staged, the system chooses a short delay at random (to prevent a driver being able to anticipate the start), then starts the race. The light sequence at this point varies slightly. For example, in NHRA Professional classes, three amber lights on the tree flash simultaneously, followed 0.4 seconds later by a green light (this is also known as a "pro tree"). In NHRA Sportsman classes, the amber lights illuminate in sequence from top to bottom, 0.5 seconds apart, followed 0.5 seconds later by the green light (this is also known as a "sportsman tree" or "full tree"). If a vehicle leaves the starting line before the green light illuminates, the red light for that lane illuminates instead, and the driver is disqualified (also known as red lighting). In a handicap start, the green light automatically lights up for the first driver, and the red light is only lit in the proper lane after both cars have launched if one driver leaves early, or if both drivers left early, the driver whose reaction time is worse (if one lane has a -.015 and the other lane has a -.022, the lane of the driver who committed a 0.022 is given the red light after both cars have left), as a red light infraction is only assessed to the driver with the worse infraction, if both drivers leave early. Even if both drivers leave early, the green light is automatically lit for the driver that left last, and they still may win the pass (as in the 2014 NHRA Auto Club Pro Stock final, Erica Enders-Stevens and Jason Line both committed red light infractions; only Line was assessed with a red light, as he was -.011 versus Enders-Stevens' -.002).
Several measurements are taken for each race: reaction time, elapsed time, and speed. Reaction time is the period from the green light illuminating to the vehicle leaving the staging beams or breaking the guard beam. Elapsed time is the period from the vehicle leaving the starting line to crossing the finish line. Speed is measured through a speed trap covering the final 66 feet (20 m) to the finish line, indicating average speed of the vehicle in that distance.
Except where a breakout rule is in place, the winner is the first vehicle to cross the finish line, and therefore the driver with the lowest combined reaction time and elapsed time. Because these times are measured separately, a driver with a slower elapsed time can actually win if that driver's advantage in reaction time exceeds the elapsed time difference. In heads-up racing, this is known as a holeshot win. In categories where a breakout rule is in effect (for example, NHRA Junior Dragster, Super Comp, Super Gas, Super Stock, and Stock classes, as well as some dial-in classes), if a competitor is faster than his or her predetermined time (a "breakout"), that competitor loses. If both competitors are faster than their predetermined times, the competitor who breaks out by less time wins. Regardless, a red light foul is worse than a breakout, except in Junior Dragster where exceeding the absolute limit is a cause for disqualification.
Most race events use a traditional bracket system, where the losing car and driver are eliminated from the event while the winner advances to the next round, until a champion is crowned. Events can range from 16 to over 100 car brackets. Drivers are typically seeded by elapsed times in qualifying. In bracket racing without a breakout (such as NHRA Competition Eliminator), pairings are based on times compared to their index (faster than index for class is better). In bracket racing with a breakout (Stock, Super Stock, but also the NHRA's Super classes), the closest to the index is favorable.
A popular alternative to the standard eliminations format is the Chicago Style format (also called the Three Round format in Australia), named for the US 30 Dragstrip near Merrillville, Indiana where a midweek meet featured this format. All entered cars participate in one qualifying round, and then are paired for the elimination round. The two fastest times among winners from this round participate in the championship round. Depending on the organization, the next two fastest times may play for third, then fifth, and so forth, in consolation rounds. Currently, an IHRA 400 Thunder championship race in Australia uses the format.
The standard distance of a drag race is 1,320 feet, 402 m, or 1/4 mile( +- 0,2% FIA & NHRA rules). However, due to safety concerns, certain sanctioning bodies (notably the NHRA for its Top Fuel and Funny Car classes) have shortened races to 1,000 feet. Some drag strips are even shorter and run 660 feet, 201 m, or 1/8 mile. The 1,000 foot distance is now also popular with bracket racing, especially in meets where there are 1/8 mile cars and 1/4 mile cars racing together, and is used by the revived American Drag Racing League for its primary classes (not Jr Dragster). Some organizations that deal with Pro Modified and "Mountain Motor" Pro Stock cars (Professional Drag Racers Association) use the 1/8 mile distance, even if the tracks are 1/4 mile tracks.
The National Hot Rod Association (NHRA) oversees the majority of drag racing events in North America. The next largest organization is the International Hot Rod Association (IHRA). One of the major sanctioning bodies in drag racing.
The World Drag Racing Alliance (WDRA) WDRA is the first fully functioning sanctioning body created (one that actually sanctions facilities) since 1970.
Besides NHRA, IHRA, and WDRA, there are several other racing organizations were created over the past several decades. The Professional Drag Racers Association (PDRA), founded in 2014, races 1/8 mile with events throughout the US. The National Mustang Racers Association (NMRA), started in 1999, is considered the leader in Ford motorsports events. The National Muscle Car Association (NMCA), is the longest running major street-legal drag racing association. The NMCA provides competitive and organized national event competitions from grassroots drag racers all the way to the powerful and fast VP Racing Fuels Xtreme Pro Mod racers.
There are also niche organizations for muscle cars and nostalgia vehicles. The Nostalgia Drag Racing League (NDRL) based in Brownsburg, IN, runs a series of 1/4 mile (402 m) drag races in the Midwest for 1979 and older nostalgic appearing cars, with four classes of competition running in an index system. Pro 7.0 and Pro 7.50 run heads up 200 mile per hour (320 kilometre per hour) passes, while Pro Comp and Pro Gas run 8.0 to 10.0 indices. NDRL competition vehicles typically include Front Engine Dragsters, Altereds, Funny Cars, early Pro Stock clones, Super Stocks and Gassers.
The National Electric Drag Racing Association (NEDRA) races electric vehicles against high performance gasoline-powered vehicles such as Dodge Vipers or classic muscle cars in 1/4 and 1/8 mile (402 m & 201 m) races. The current electric drag racing record is 6.940 seconds at 201.37 mph (324.0736 km/h) for a quarter mile (402 m). Another niche organization is the VWDRC which run a VW-only championship with vehicles running under 7 seconds.
Prior to the founding of the NHRA and IHRA, smaller organizations sanctioned drag racing in the early years, which included the competing AHRA in the United States from 1955 to 2005.
The first Australian Nationals event was run in 1965 at Riverside raceway, near Melbourne. The Australian National Drag Racing Association (ANDRA) was established in 1973, and today they claim they are the "best in the world outside the United States". ANDRA sanctions races throughout Australia and throughout the year at all levels, from Junior Dragster to Top Fuel.
The ANDRA Drag Racing Series is for professional drivers and riders and includes Top Fuel, Top Alcohol, Top Doorslammer (similar to the USA Pro Modified class), Pro Stock (using 400 cubic inch engines (6.5 litres)), Top Bike and Pro Stock Motorcycle.
The Summit Sportsman Series is for ANDRA sportsman drivers and riders and includes Competition, Super Stock, Super Compact, Competition Bike, Supercharged Outlaws, Top Sportsman, Modified, Super Sedan, Modified Bike, Super Street and Junior Dragster.
In 2015, after a dispute with ANDRA, Sydney Dragway, Willowbank Raceway and the Perth Motorplex invited the International Hot Rod Association (IHRA) to sanction events at their tracks. Shortly thereafter the Perth Motorplex reverted to ANDRA sanction. Although greatly assisted by ANDRA prior to its construction, Springmount Raceway opted for IHRA sanction. The 400 Thunder Series targets professional racers to its races. Intended to be the premier Drag racing series in Australia it has never been able to run a truly National series and has been on a steady decline since its inception. Most recently Top Fuel Australia (the organization that represents the Top Fuel owners) recently extracted itself from the 400 Thunder series. ANDRA recently launched a new National series that will initially cater for Top Doorslammer and Top Fue Motorcycle. This series will provide a greater National coverage than the 400 Thunder Series did and will soon add other Professional categories. In 2021 Heathcote Park Raceway in Victoria was sold to new ownership and has since been sanctioned by IHRA for small regional events.
Drag racing was imported to Europe by American NATO troops during the Cold War. Races were held in West Germany beginning in the 1960s at the airbases at Ramstein and Sembach and in the UK at various airstrips and racing circuits before the opening of Europe's first permanent drag strip at Santa Pod Raceway in 1966.
The FIA organises a Europe-wide four wheeled championship for the Top Fuel, Top Methanol Dragster, Top Methanol Funny Car, Pro Modified and Pro Stock classes. FIM Europe organises a similar championship for bike classes. In addition, championships are run for sportsman classes in many countries throughout Europe by the various national motorsport governing bodies.
Drag racing in New Zealand started in the 1960s. The New Zealand Hot Rod Association (NZHRA) sanctioned what is believed to have been the first drag meeting at an open cut coal mine at Kopuku, south of Auckland, sometime in 1966. In 1973, the first and only purpose built drag strip opened in Meremere by the Pukekohe Hot Rod Club. In April 1993 the governance of drag racing was separated from the NZHRA and the New Zealand Drag Racing Association (NZDRA) was formed. In 2014, New Zealand's second purpose built drag strip – Masterton Motorplex – opened.
The first New Zealand Drag Racing Nationals was held in the 1966/67 season at Kopuku, near Auckland.
There are now two governing bodies operating drag racing in New Zealand with the Florida-based International Hot Rod Association sanctioning both of New Zealands major tracks at Ruapuna (Pegasus Bay Drag Racing Association Archived 16 May 2014 at the Wayback Machine) in the South Island and Meremere Dragway Inc in the North Island which is now become the best drag strip in NZ. However, the official ASN of the sport, per FIA regulations, is the New Zealand Drag Racing Association.
Many countries in South America race 200 meters, unlike in the United States and Australia, where the quarter-mile, or, 400 meters, respectively, is typical.
Organized drag racing in Colombia is the responsibility of Club G3, a private organization. The events take place at Autódromo de Tocancipá.
Local "muscles" like Chevrolet Opala and Chevrolet Chevette (both models brought from Opel with increased motors from Detroit, US) are the show makers for brazilian dragstrips.
Curaçao
On the island of Curaçao, organization of drag racing events is handled by the Curaçao Autosport Foundation (FAC) All racing events, including street legal competitions, happen at the Curaçao International Raceway.
On the island of Aruba, all racing events, including street legal competitions, happen at Palomarga International Raceway.
Barbados
On the island of Barbados, organization of drag racing events is done by the Barbados Association of Dragsters and Drifters. Currently the drag racing is done at Bushy Park racing circuit over 1/8 mile, while "acceleration tests" of 1/4 mile are done at the Paragon military base.
Saint Lucia
On the Island of Saint Lucia, organization of drag racing events is done by no-one. All local groups are tie ups. Currently races are held at the US Old military base also known as the "Ca Ca Beff", "The Base" near the Hewanorra International Airport in Vieux Fort.
Dominican Republic
On Santo Domingo, organization of drag racing events is done by Autodromo Sunix and they happen at the Autodromo Sunix, close to the Airport SDQ.
Organized drag racing is rapidly growing in India. The country's first drag race meet was organized by Autocar India in Mumbai in 2002. Since then there have been many drag racing events in India. The most popular event is Elite Octanes' Valley Run which is held at Ambey Valley air strip in Loanavla every year.
The biggest drag series event was organized by India Speed Week with three different locations around India. After the series two riders were chosen to represent the country 2017 initiative to bring 11 times world drag racing champion Rickey Gadson to India. The initiative was executed during the Valley Run 2017 event, which gave the participants a platform to perform at the highest level globally. Rickey Gadson, as an extension of the initiative invited two of the top performing drag racers to visit USA to train and get an opportunity to represent India at the World Finals of drag racing held on 16-18 November 2018 in Valdosta GA, USA. As a result the two riders performed in their maiden event outside India. Also during the event, Amit Sharma, the fastest drag racer in Indian drag racing history, produced a time slip of 8.87 sec's – the fastest ever by any Indian.
Drag racing is also gaining popularity in Pakistan, with private organizations sponsoring such events. The Bahria Town housing project recently organized a drag racing event in Rawalpindi with the help of some of the country's best drivers.
Sri Lanka has seen an immense growth in drag racing due to legal meets held by the Ceylon Motor Sports Club, an FIA sanctioned body. In recent years, exotic cars and Japanese power houses have been taking part in these popular events.
Drag racing is an established sport in South Africa, with a number of strips around the country including Tarlton International Raceway and ODI Raceway. Drag racing is controlled by Motorsport South Africa and all drivers are required to hold a valid Motorsport South Africa license. Drivers can compete in a number of categories including Top Eliminator, Senior Eliminator, Super Competition Eliminator, Competition Eliminator, Pro Street Bikes, Superbike Eliminator, Supersport Shootout (motorcycle), Street Modified, and Factory Stock.
Drag racing in Russia started in 2004 in Moscow when the Russian Automotive Federation (RAF) sanctioned it as an official motorsport. Drag Racing became popular in Russia after "The Fast and the Furious" film in 2001, but competitions were illegal before 2004. The most outstanding drag racing event of the early years was "DRAG BITVA" (Drag Battle) which took place in Krasnoyarsk, Siberia from 2005 to 2008. Krasnoyarsk is located in the middle of Russia, so it was the best place to bring all the fastest cars from all over the country. Due to the financial situation "DRAG BITVA" was canceled in 2009 and never came back. It was difficult times for drag racing in Russia from 2009 to 2014, but it was supported by enthusiasts in every region. There were a lot of competitions but it was not as big as "DRAG BITVA". In 2014 Dragtimes company in partnership with SMP Racing became the Russian Drag Racing Championship (SMP RDRC) promoters, since then Drag Racing in Russia became more professional. From the very beginning to 2014 only streetcars were allowed to compete in Russia. Now it's also allowed to run promods and dragsters in SMP RDRC. Thanks to the efforts of SMP RDRC promoters in 2019 the first professional dragstrip in Russia "RDRC Racepark" was built. It's located near Moscow in 40 kilometers of downtown at the former airfield Bykovo. It gave many opportunities to test the cars and make new records. Before the track was built, competitions took place on straight parts of circuits, so it was not allowed to prepare the whole 1/4 mile, only 1/8 and the tracks were available for drag racers except racing weekends of local or national events. From the very beginning one of the main ideas of the promoters was to increase the quality and reach of live broadcasts, so SMP RDRC became the first racing series with its video production and remains so to this day.
Russian Championship has four classes:
Regional Series also have four classes divided by ET:
The national record belongs to 4-time national champion Dmitry Samorukov: 6.325 seconds at 328.76 km/h (204.28 mph). It was set in a special record run in 2016 on Dodge Viper Doorslammer in Grozny, Chechen Republic at "Fort Grozny" racetrack.
Dmitry Samorukov was the first Russian participant of the FIA European Championship on a newly built Chevrolet Camaro in the most competitive Promod class in 2019. After six stages of the competition, he took 10th of 38 places overall.
Russian driver Dmitry Kapustin on Nissan Skyline GT-R R32 is holding the European record of AWD streetcars: 7.182 seconds at 312.77 km/h (194.35 mph). The record was set in a qualifying run in Grozny, Chechen Republic at "Fort Grozny" racetrack in 2018.
1/2 mile races are also popular in Russia. "Unlim 500+" is the main 1/2 mile race in Russia. It's a supercar and sportscar festival where only 500+ hp cars are allowed (e. g. Nissan GT-R, McLaren 720S, Lamborghini Aventador, Porsche 911, Ferrari 488, etc.). The national record on 1/2 mile distance also belongs to Dmitry Samorukov on Nissan GT-R R 35: 13.305 seconds at 346.48 km/h (215.29 mph). The record was set on a test and tune day at the "RDRC Racepark" track in 2020.
There are hundreds of classes in drag racing, each with different requirements and restrictions on things such as weight, engine size, body style, modifications, and many others. NHRA and IHRA share some of these classes, but many are solely used by one sanctioning body or the other. The NHRA boasts over 200 classes, while the IHRA has fewer. Some IHRA classes have multiple sub-classes in them to differentiate by engine components and other features. There is even a class for aspiring youngsters, Junior Dragster, which typically uses an eighth-mile track, also favored by VW racers.
In 1997, the FIA (cars) and UEM (bikes) began sanctioning drag racing in Europe with a fully established European Drag Racing Championship, in cooperation (and rules compliance) with NHRA. The major European drag strips include Santa Pod Raceway in Podington, England; Alastaro Circuit, Finland; Mantorp Park, Sweden; Gardermoen Raceway, Norway and the Hockenheimring in Germany.
There is a somewhat arbitrary definition of what constitutes a "professional" class. The NHRA includes 5 pro classes; Top Fuel, Funny Car, Pro Stock, Pro Modified and Pro Stock Motorcycle. The FIA features a different set of 5 pro classes; Top Fuel, Top Methanol Dragster, Top Methanol Funny Car, Pro Modified and Pro Stock. Other sanctioning bodies have similarly different definitions. A partial list of classes includes:
A complete listing of all classes can be found on the respective NHRA and IHRA official websites.
The UEM also has a different structure of professional categories with Top Fuel Bike, Super Twin Top Fuel Bike, and Pro Stock Bike contested, leaving the entire European series with a total of 8 professional categories.
To allow different cars to compete against each other, some competitions are raced on a handicap basis, with faster cars delayed on the starting line enough to theoretically even things up with the slower car. This may be based on rule differences between the cars in stock, super stock, and modified classes, or on a competitor's chosen "dial-in" in bracket racing.
For a list of drag racing world records in each class, see Dragstrip#Quarter mile times.
A 'dial-in' is a time the driver estimates it will take their car to cross the finish line, and is generally displayed on one or more windows so the starter can adjust the starting lights on the tree accordingly. The slower car will then get a head start equal to the difference in the two dial-ins, so if both cars perform perfectly, they would cross the finish line dead even. If either car goes faster than its dial-in (called breaking out), it is disqualified regardless of who has the lower elapsed time; if both cars break out, the one who breaks out by the smallest amount wins. However, if a driver had jump-started (red light) or crossed a boundary line, both violations override any break out (except in some classes with an absolute break out rule such as Junior classes).
The effect of the bracket racing rules is to place a premium on consistency of performance of the driver and car rather than on raw speed, in that victory goes to the driver able to precisely predict elapsed time, whether it is fast or slow. This in turn makes victory much less dependent on budget, and more dependent on skill, making it popular with casual weekend racers. | [
{
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"text": "Drag racing is a type of motor racing in which automobiles or motorcycles compete, usually two at a time, to be first to cross a set finish line. The race follows a short, straight course from a standing start over a measured distance, most commonly 1⁄4 mi (1,320 ft; 402 m), with a shorter, 1,000 ft (0.19 mi; 304.80 m) distance becoming increasingly popular, as it has become the standard for Top Fuel dragsters and Funny Cars, where some major bracket races and other sanctioning bodies have adopted it as the standard. The 1⁄8 mi (660 ft; 201 m) is also popular in some circles. Electronic timing and speed sensing systems have been used to record race results since the 1960s.",
"title": ""
},
{
"paragraph_id": 1,
"text": "The history of automobiles and motorcycles being used for drag racing is nearly as long as the history of motorized vehicles themselves, and has taken the form of both illegal street racing and as a regulated motorsport.",
"title": ""
},
{
"paragraph_id": 2,
"text": "Drag racing started in the 1940s. World War II veterans were prominently involved, and some early drag races were done at decommissioned aircraft bases with landing strips that made them an ideal place for the sport. In 1951, Wally Parks formed the National Hot Rod Association (NHRA). The organization banned the use of nitromethane in 1957, calling it unsafe, in part through the efforts of C. J. Hart; the ban would be lifted in 1963.",
"title": "History"
},
{
"paragraph_id": 3,
"text": "Several other racing organizations were created over the past several decades, such as the Professional Drag Racers Association (PDRA) founded in 2014.",
"title": "History"
},
{
"paragraph_id": 4,
"text": "Thanks, in part, to the Discovery series Street Outlaws, fandom for drag racing has seen a resurgence in the past decade.",
"title": "History"
},
{
"paragraph_id": 5,
"text": "Push starts to get engines running were necessary until the National Hot Rod Association (NHRA) mandated self-starters in 1976. After burnouts, cars would be pushed back by crews; this persisted until NHRA required reversing systems in 1980. Don Garlits was the first to do burnouts across the starting line, which is now standard practice. Each driver then backs up to and stages at the starting line.",
"title": "Basics of drag racing"
},
{
"paragraph_id": 6,
"text": "Before each race (commonly known as a pass), each driver is allowed to perform a burnout, which heats the driving tires and lays rubber down at the beginning of the track, improving traction. The cars run through a \"water box\" (formerly a \"bleach box\", before bleach was replaced by flammable traction compound, which produced spectacular, and dangerous, flame burnouts; the hazard led NHRA to mandate use of water in the 1970s).",
"title": "Basics of drag racing"
},
{
"paragraph_id": 7,
"text": "Modern races are started electronically by a system known as a Christmas tree, which consists of a column of lights for each driver/lane, and two light beam sensors per lane on the track at the starting line. Current NHRA trees, for example, feature one blue light (split into halves), then three amber, one green, and one red. When the first light beam is broken by a vehicle's front tire(s), the vehicle is \"pre-staged\" (approximately 7 inches (180 mm) from the starting line), and the pre-stage indicator on the tree is lit. When the second light beam is broken, the vehicle is \"staged\", and the stage indicator on the tree is lit. Vehicles may then leave the pre-stage beam, but must remain in the stage beam until the race starts.",
"title": "Basics of drag racing"
},
{
"paragraph_id": 8,
"text": "Once one competitor is staged, their opponent has a set amount of time to stage or they will be instantly disqualified, indicated by a red light on the tree. Otherwise, once both drivers are staged, the system chooses a short delay at random (to prevent a driver being able to anticipate the start), then starts the race. The light sequence at this point varies slightly. For example, in NHRA Professional classes, three amber lights on the tree flash simultaneously, followed 0.4 seconds later by a green light (this is also known as a \"pro tree\"). In NHRA Sportsman classes, the amber lights illuminate in sequence from top to bottom, 0.5 seconds apart, followed 0.5 seconds later by the green light (this is also known as a \"sportsman tree\" or \"full tree\"). If a vehicle leaves the starting line before the green light illuminates, the red light for that lane illuminates instead, and the driver is disqualified (also known as red lighting). In a handicap start, the green light automatically lights up for the first driver, and the red light is only lit in the proper lane after both cars have launched if one driver leaves early, or if both drivers left early, the driver whose reaction time is worse (if one lane has a -.015 and the other lane has a -.022, the lane of the driver who committed a 0.022 is given the red light after both cars have left), as a red light infraction is only assessed to the driver with the worse infraction, if both drivers leave early. Even if both drivers leave early, the green light is automatically lit for the driver that left last, and they still may win the pass (as in the 2014 NHRA Auto Club Pro Stock final, Erica Enders-Stevens and Jason Line both committed red light infractions; only Line was assessed with a red light, as he was -.011 versus Enders-Stevens' -.002).",
"title": "Basics of drag racing"
},
{
"paragraph_id": 9,
"text": "Several measurements are taken for each race: reaction time, elapsed time, and speed. Reaction time is the period from the green light illuminating to the vehicle leaving the staging beams or breaking the guard beam. Elapsed time is the period from the vehicle leaving the starting line to crossing the finish line. Speed is measured through a speed trap covering the final 66 feet (20 m) to the finish line, indicating average speed of the vehicle in that distance.",
"title": "Basics of drag racing"
},
{
"paragraph_id": 10,
"text": "Except where a breakout rule is in place, the winner is the first vehicle to cross the finish line, and therefore the driver with the lowest combined reaction time and elapsed time. Because these times are measured separately, a driver with a slower elapsed time can actually win if that driver's advantage in reaction time exceeds the elapsed time difference. In heads-up racing, this is known as a holeshot win. In categories where a breakout rule is in effect (for example, NHRA Junior Dragster, Super Comp, Super Gas, Super Stock, and Stock classes, as well as some dial-in classes), if a competitor is faster than his or her predetermined time (a \"breakout\"), that competitor loses. If both competitors are faster than their predetermined times, the competitor who breaks out by less time wins. Regardless, a red light foul is worse than a breakout, except in Junior Dragster where exceeding the absolute limit is a cause for disqualification.",
"title": "Basics of drag racing"
},
{
"paragraph_id": 11,
"text": "Most race events use a traditional bracket system, where the losing car and driver are eliminated from the event while the winner advances to the next round, until a champion is crowned. Events can range from 16 to over 100 car brackets. Drivers are typically seeded by elapsed times in qualifying. In bracket racing without a breakout (such as NHRA Competition Eliminator), pairings are based on times compared to their index (faster than index for class is better). In bracket racing with a breakout (Stock, Super Stock, but also the NHRA's Super classes), the closest to the index is favorable.",
"title": "Basics of drag racing"
},
{
"paragraph_id": 12,
"text": "A popular alternative to the standard eliminations format is the Chicago Style format (also called the Three Round format in Australia), named for the US 30 Dragstrip near Merrillville, Indiana where a midweek meet featured this format. All entered cars participate in one qualifying round, and then are paired for the elimination round. The two fastest times among winners from this round participate in the championship round. Depending on the organization, the next two fastest times may play for third, then fifth, and so forth, in consolation rounds. Currently, an IHRA 400 Thunder championship race in Australia uses the format.",
"title": "Basics of drag racing"
},
{
"paragraph_id": 13,
"text": "The standard distance of a drag race is 1,320 feet, 402 m, or 1/4 mile( +- 0,2% FIA & NHRA rules). However, due to safety concerns, certain sanctioning bodies (notably the NHRA for its Top Fuel and Funny Car classes) have shortened races to 1,000 feet. Some drag strips are even shorter and run 660 feet, 201 m, or 1/8 mile. The 1,000 foot distance is now also popular with bracket racing, especially in meets where there are 1/8 mile cars and 1/4 mile cars racing together, and is used by the revived American Drag Racing League for its primary classes (not Jr Dragster). Some organizations that deal with Pro Modified and \"Mountain Motor\" Pro Stock cars (Professional Drag Racers Association) use the 1/8 mile distance, even if the tracks are 1/4 mile tracks.",
"title": "Basics of drag racing"
},
{
"paragraph_id": 14,
"text": "The National Hot Rod Association (NHRA) oversees the majority of drag racing events in North America. The next largest organization is the International Hot Rod Association (IHRA). One of the major sanctioning bodies in drag racing.",
"title": "Racing organizations"
},
{
"paragraph_id": 15,
"text": "The World Drag Racing Alliance (WDRA) WDRA is the first fully functioning sanctioning body created (one that actually sanctions facilities) since 1970.",
"title": "Racing organizations"
},
{
"paragraph_id": 16,
"text": "Besides NHRA, IHRA, and WDRA, there are several other racing organizations were created over the past several decades. The Professional Drag Racers Association (PDRA), founded in 2014, races 1/8 mile with events throughout the US. The National Mustang Racers Association (NMRA), started in 1999, is considered the leader in Ford motorsports events. The National Muscle Car Association (NMCA), is the longest running major street-legal drag racing association. The NMCA provides competitive and organized national event competitions from grassroots drag racers all the way to the powerful and fast VP Racing Fuels Xtreme Pro Mod racers.",
"title": "Racing organizations"
},
{
"paragraph_id": 17,
"text": "There are also niche organizations for muscle cars and nostalgia vehicles. The Nostalgia Drag Racing League (NDRL) based in Brownsburg, IN, runs a series of 1/4 mile (402 m) drag races in the Midwest for 1979 and older nostalgic appearing cars, with four classes of competition running in an index system. Pro 7.0 and Pro 7.50 run heads up 200 mile per hour (320 kilometre per hour) passes, while Pro Comp and Pro Gas run 8.0 to 10.0 indices. NDRL competition vehicles typically include Front Engine Dragsters, Altereds, Funny Cars, early Pro Stock clones, Super Stocks and Gassers.",
"title": "Racing organizations"
},
{
"paragraph_id": 18,
"text": "The National Electric Drag Racing Association (NEDRA) races electric vehicles against high performance gasoline-powered vehicles such as Dodge Vipers or classic muscle cars in 1/4 and 1/8 mile (402 m & 201 m) races. The current electric drag racing record is 6.940 seconds at 201.37 mph (324.0736 km/h) for a quarter mile (402 m). Another niche organization is the VWDRC which run a VW-only championship with vehicles running under 7 seconds.",
"title": "Racing organizations"
},
{
"paragraph_id": 19,
"text": "Prior to the founding of the NHRA and IHRA, smaller organizations sanctioned drag racing in the early years, which included the competing AHRA in the United States from 1955 to 2005.",
"title": "Racing organizations"
},
{
"paragraph_id": 20,
"text": "The first Australian Nationals event was run in 1965 at Riverside raceway, near Melbourne. The Australian National Drag Racing Association (ANDRA) was established in 1973, and today they claim they are the \"best in the world outside the United States\". ANDRA sanctions races throughout Australia and throughout the year at all levels, from Junior Dragster to Top Fuel.",
"title": "Racing organizations"
},
{
"paragraph_id": 21,
"text": "The ANDRA Drag Racing Series is for professional drivers and riders and includes Top Fuel, Top Alcohol, Top Doorslammer (similar to the USA Pro Modified class), Pro Stock (using 400 cubic inch engines (6.5 litres)), Top Bike and Pro Stock Motorcycle.",
"title": "Racing organizations"
},
{
"paragraph_id": 22,
"text": "The Summit Sportsman Series is for ANDRA sportsman drivers and riders and includes Competition, Super Stock, Super Compact, Competition Bike, Supercharged Outlaws, Top Sportsman, Modified, Super Sedan, Modified Bike, Super Street and Junior Dragster.",
"title": "Racing organizations"
},
{
"paragraph_id": 23,
"text": "In 2015, after a dispute with ANDRA, Sydney Dragway, Willowbank Raceway and the Perth Motorplex invited the International Hot Rod Association (IHRA) to sanction events at their tracks. Shortly thereafter the Perth Motorplex reverted to ANDRA sanction. Although greatly assisted by ANDRA prior to its construction, Springmount Raceway opted for IHRA sanction. The 400 Thunder Series targets professional racers to its races. Intended to be the premier Drag racing series in Australia it has never been able to run a truly National series and has been on a steady decline since its inception. Most recently Top Fuel Australia (the organization that represents the Top Fuel owners) recently extracted itself from the 400 Thunder series. ANDRA recently launched a new National series that will initially cater for Top Doorslammer and Top Fue Motorcycle. This series will provide a greater National coverage than the 400 Thunder Series did and will soon add other Professional categories. In 2021 Heathcote Park Raceway in Victoria was sold to new ownership and has since been sanctioned by IHRA for small regional events.",
"title": "Racing organizations"
},
{
"paragraph_id": 24,
"text": "Drag racing was imported to Europe by American NATO troops during the Cold War. Races were held in West Germany beginning in the 1960s at the airbases at Ramstein and Sembach and in the UK at various airstrips and racing circuits before the opening of Europe's first permanent drag strip at Santa Pod Raceway in 1966.",
"title": "Racing organizations"
},
{
"paragraph_id": 25,
"text": "The FIA organises a Europe-wide four wheeled championship for the Top Fuel, Top Methanol Dragster, Top Methanol Funny Car, Pro Modified and Pro Stock classes. FIM Europe organises a similar championship for bike classes. In addition, championships are run for sportsman classes in many countries throughout Europe by the various national motorsport governing bodies.",
"title": "Racing organizations"
},
{
"paragraph_id": 26,
"text": "Drag racing in New Zealand started in the 1960s. The New Zealand Hot Rod Association (NZHRA) sanctioned what is believed to have been the first drag meeting at an open cut coal mine at Kopuku, south of Auckland, sometime in 1966. In 1973, the first and only purpose built drag strip opened in Meremere by the Pukekohe Hot Rod Club. In April 1993 the governance of drag racing was separated from the NZHRA and the New Zealand Drag Racing Association (NZDRA) was formed. In 2014, New Zealand's second purpose built drag strip – Masterton Motorplex – opened.",
"title": "Racing organizations"
},
{
"paragraph_id": 27,
"text": "The first New Zealand Drag Racing Nationals was held in the 1966/67 season at Kopuku, near Auckland.",
"title": "Racing organizations"
},
{
"paragraph_id": 28,
"text": "There are now two governing bodies operating drag racing in New Zealand with the Florida-based International Hot Rod Association sanctioning both of New Zealands major tracks at Ruapuna (Pegasus Bay Drag Racing Association Archived 16 May 2014 at the Wayback Machine) in the South Island and Meremere Dragway Inc in the North Island which is now become the best drag strip in NZ. However, the official ASN of the sport, per FIA regulations, is the New Zealand Drag Racing Association.",
"title": "Racing organizations"
},
{
"paragraph_id": 29,
"text": "Many countries in South America race 200 meters, unlike in the United States and Australia, where the quarter-mile, or, 400 meters, respectively, is typical.",
"title": "Racing organizations"
},
{
"paragraph_id": 30,
"text": "Organized drag racing in Colombia is the responsibility of Club G3, a private organization. The events take place at Autódromo de Tocancipá.",
"title": "Racing organizations"
},
{
"paragraph_id": 31,
"text": "Local \"muscles\" like Chevrolet Opala and Chevrolet Chevette (both models brought from Opel with increased motors from Detroit, US) are the show makers for brazilian dragstrips.",
"title": "Racing organizations"
},
{
"paragraph_id": 32,
"text": "Curaçao",
"title": "Racing organizations"
},
{
"paragraph_id": 33,
"text": "On the island of Curaçao, organization of drag racing events is handled by the Curaçao Autosport Foundation (FAC) All racing events, including street legal competitions, happen at the Curaçao International Raceway.",
"title": "Racing organizations"
},
{
"paragraph_id": 34,
"text": "On the island of Aruba, all racing events, including street legal competitions, happen at Palomarga International Raceway.",
"title": "Racing organizations"
},
{
"paragraph_id": 35,
"text": "Barbados",
"title": "Racing organizations"
},
{
"paragraph_id": 36,
"text": "On the island of Barbados, organization of drag racing events is done by the Barbados Association of Dragsters and Drifters. Currently the drag racing is done at Bushy Park racing circuit over 1/8 mile, while \"acceleration tests\" of 1/4 mile are done at the Paragon military base.",
"title": "Racing organizations"
},
{
"paragraph_id": 37,
"text": "Saint Lucia",
"title": "Racing organizations"
},
{
"paragraph_id": 38,
"text": "On the Island of Saint Lucia, organization of drag racing events is done by no-one. All local groups are tie ups. Currently races are held at the US Old military base also known as the \"Ca Ca Beff\", \"The Base\" near the Hewanorra International Airport in Vieux Fort.",
"title": "Racing organizations"
},
{
"paragraph_id": 39,
"text": "Dominican Republic",
"title": "Racing organizations"
},
{
"paragraph_id": 40,
"text": "On Santo Domingo, organization of drag racing events is done by Autodromo Sunix and they happen at the Autodromo Sunix, close to the Airport SDQ.",
"title": "Racing organizations"
},
{
"paragraph_id": 41,
"text": "Organized drag racing is rapidly growing in India. The country's first drag race meet was organized by Autocar India in Mumbai in 2002. Since then there have been many drag racing events in India. The most popular event is Elite Octanes' Valley Run which is held at Ambey Valley air strip in Loanavla every year.",
"title": "Racing organizations"
},
{
"paragraph_id": 42,
"text": "The biggest drag series event was organized by India Speed Week with three different locations around India. After the series two riders were chosen to represent the country 2017 initiative to bring 11 times world drag racing champion Rickey Gadson to India. The initiative was executed during the Valley Run 2017 event, which gave the participants a platform to perform at the highest level globally. Rickey Gadson, as an extension of the initiative invited two of the top performing drag racers to visit USA to train and get an opportunity to represent India at the World Finals of drag racing held on 16-18 November 2018 in Valdosta GA, USA. As a result the two riders performed in their maiden event outside India. Also during the event, Amit Sharma, the fastest drag racer in Indian drag racing history, produced a time slip of 8.87 sec's – the fastest ever by any Indian.",
"title": "Racing organizations"
},
{
"paragraph_id": 43,
"text": "Drag racing is also gaining popularity in Pakistan, with private organizations sponsoring such events. The Bahria Town housing project recently organized a drag racing event in Rawalpindi with the help of some of the country's best drivers.",
"title": "Racing organizations"
},
{
"paragraph_id": 44,
"text": "Sri Lanka has seen an immense growth in drag racing due to legal meets held by the Ceylon Motor Sports Club, an FIA sanctioned body. In recent years, exotic cars and Japanese power houses have been taking part in these popular events.",
"title": "Racing organizations"
},
{
"paragraph_id": 45,
"text": "Drag racing is an established sport in South Africa, with a number of strips around the country including Tarlton International Raceway and ODI Raceway. Drag racing is controlled by Motorsport South Africa and all drivers are required to hold a valid Motorsport South Africa license. Drivers can compete in a number of categories including Top Eliminator, Senior Eliminator, Super Competition Eliminator, Competition Eliminator, Pro Street Bikes, Superbike Eliminator, Supersport Shootout (motorcycle), Street Modified, and Factory Stock.",
"title": "Racing organizations"
},
{
"paragraph_id": 46,
"text": "Drag racing in Russia started in 2004 in Moscow when the Russian Automotive Federation (RAF) sanctioned it as an official motorsport. Drag Racing became popular in Russia after \"The Fast and the Furious\" film in 2001, but competitions were illegal before 2004. The most outstanding drag racing event of the early years was \"DRAG BITVA\" (Drag Battle) which took place in Krasnoyarsk, Siberia from 2005 to 2008. Krasnoyarsk is located in the middle of Russia, so it was the best place to bring all the fastest cars from all over the country. Due to the financial situation \"DRAG BITVA\" was canceled in 2009 and never came back. It was difficult times for drag racing in Russia from 2009 to 2014, but it was supported by enthusiasts in every region. There were a lot of competitions but it was not as big as \"DRAG BITVA\". In 2014 Dragtimes company in partnership with SMP Racing became the Russian Drag Racing Championship (SMP RDRC) promoters, since then Drag Racing in Russia became more professional. From the very beginning to 2014 only streetcars were allowed to compete in Russia. Now it's also allowed to run promods and dragsters in SMP RDRC. Thanks to the efforts of SMP RDRC promoters in 2019 the first professional dragstrip in Russia \"RDRC Racepark\" was built. It's located near Moscow in 40 kilometers of downtown at the former airfield Bykovo. It gave many opportunities to test the cars and make new records. Before the track was built, competitions took place on straight parts of circuits, so it was not allowed to prepare the whole 1/4 mile, only 1/8 and the tracks were available for drag racers except racing weekends of local or national events. From the very beginning one of the main ideas of the promoters was to increase the quality and reach of live broadcasts, so SMP RDRC became the first racing series with its video production and remains so to this day.",
"title": "Racing organizations"
},
{
"paragraph_id": 47,
"text": "Russian Championship has four classes:",
"title": "Racing organizations"
},
{
"paragraph_id": 48,
"text": "Regional Series also have four classes divided by ET:",
"title": "Racing organizations"
},
{
"paragraph_id": 49,
"text": "The national record belongs to 4-time national champion Dmitry Samorukov: 6.325 seconds at 328.76 km/h (204.28 mph). It was set in a special record run in 2016 on Dodge Viper Doorslammer in Grozny, Chechen Republic at \"Fort Grozny\" racetrack.",
"title": "Racing organizations"
},
{
"paragraph_id": 50,
"text": "Dmitry Samorukov was the first Russian participant of the FIA European Championship on a newly built Chevrolet Camaro in the most competitive Promod class in 2019. After six stages of the competition, he took 10th of 38 places overall.",
"title": "Racing organizations"
},
{
"paragraph_id": 51,
"text": "Russian driver Dmitry Kapustin on Nissan Skyline GT-R R32 is holding the European record of AWD streetcars: 7.182 seconds at 312.77 km/h (194.35 mph). The record was set in a qualifying run in Grozny, Chechen Republic at \"Fort Grozny\" racetrack in 2018.",
"title": "Racing organizations"
},
{
"paragraph_id": 52,
"text": "1/2 mile races are also popular in Russia. \"Unlim 500+\" is the main 1/2 mile race in Russia. It's a supercar and sportscar festival where only 500+ hp cars are allowed (e. g. Nissan GT-R, McLaren 720S, Lamborghini Aventador, Porsche 911, Ferrari 488, etc.). The national record on 1/2 mile distance also belongs to Dmitry Samorukov on Nissan GT-R R 35: 13.305 seconds at 346.48 km/h (215.29 mph). The record was set on a test and tune day at the \"RDRC Racepark\" track in 2020.",
"title": "Racing organizations"
},
{
"paragraph_id": 53,
"text": "There are hundreds of classes in drag racing, each with different requirements and restrictions on things such as weight, engine size, body style, modifications, and many others. NHRA and IHRA share some of these classes, but many are solely used by one sanctioning body or the other. The NHRA boasts over 200 classes, while the IHRA has fewer. Some IHRA classes have multiple sub-classes in them to differentiate by engine components and other features. There is even a class for aspiring youngsters, Junior Dragster, which typically uses an eighth-mile track, also favored by VW racers.",
"title": "Classes"
},
{
"paragraph_id": 54,
"text": "In 1997, the FIA (cars) and UEM (bikes) began sanctioning drag racing in Europe with a fully established European Drag Racing Championship, in cooperation (and rules compliance) with NHRA. The major European drag strips include Santa Pod Raceway in Podington, England; Alastaro Circuit, Finland; Mantorp Park, Sweden; Gardermoen Raceway, Norway and the Hockenheimring in Germany.",
"title": "Classes"
},
{
"paragraph_id": 55,
"text": "There is a somewhat arbitrary definition of what constitutes a \"professional\" class. The NHRA includes 5 pro classes; Top Fuel, Funny Car, Pro Stock, Pro Modified and Pro Stock Motorcycle. The FIA features a different set of 5 pro classes; Top Fuel, Top Methanol Dragster, Top Methanol Funny Car, Pro Modified and Pro Stock. Other sanctioning bodies have similarly different definitions. A partial list of classes includes:",
"title": "Classes"
},
{
"paragraph_id": 56,
"text": "A complete listing of all classes can be found on the respective NHRA and IHRA official websites.",
"title": "Classes"
},
{
"paragraph_id": 57,
"text": "The UEM also has a different structure of professional categories with Top Fuel Bike, Super Twin Top Fuel Bike, and Pro Stock Bike contested, leaving the entire European series with a total of 8 professional categories.",
"title": "Classes"
},
{
"paragraph_id": 58,
"text": "To allow different cars to compete against each other, some competitions are raced on a handicap basis, with faster cars delayed on the starting line enough to theoretically even things up with the slower car. This may be based on rule differences between the cars in stock, super stock, and modified classes, or on a competitor's chosen \"dial-in\" in bracket racing.",
"title": "Classes"
},
{
"paragraph_id": 59,
"text": "For a list of drag racing world records in each class, see Dragstrip#Quarter mile times.",
"title": "Classes"
},
{
"paragraph_id": 60,
"text": "A 'dial-in' is a time the driver estimates it will take their car to cross the finish line, and is generally displayed on one or more windows so the starter can adjust the starting lights on the tree accordingly. The slower car will then get a head start equal to the difference in the two dial-ins, so if both cars perform perfectly, they would cross the finish line dead even. If either car goes faster than its dial-in (called breaking out), it is disqualified regardless of who has the lower elapsed time; if both cars break out, the one who breaks out by the smallest amount wins. However, if a driver had jump-started (red light) or crossed a boundary line, both violations override any break out (except in some classes with an absolute break out rule such as Junior classes).",
"title": "Dial-in"
},
{
"paragraph_id": 61,
"text": "The effect of the bracket racing rules is to place a premium on consistency of performance of the driver and car rather than on raw speed, in that victory goes to the driver able to precisely predict elapsed time, whether it is fast or slow. This in turn makes victory much less dependent on budget, and more dependent on skill, making it popular with casual weekend racers.",
"title": "Dial-in"
}
] | Drag racing is a type of motor racing in which automobiles or motorcycles compete, usually two at a time, to be first to cross a set finish line. The race follows a short, straight course from a standing start over a measured distance, most commonly 1⁄4 mi, with a shorter, 1,000 ft distance becoming increasingly popular, as it has become the standard for Top Fuel dragsters and Funny Cars, where some major bracket races and other sanctioning bodies have adopted it as the standard. The 1⁄8 mi is also popular in some circles. Electronic timing and speed sensing systems have been used to record race results since the 1960s. The history of automobiles and motorcycles being used for drag racing is nearly as long as the history of motorized vehicles themselves, and has taken the form of both illegal street racing and as a regulated motorsport. | 2001-08-31T08:15:35Z | 2023-11-30T13:57:09Z | [
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] | https://en.wikipedia.org/wiki/Drag_racing |
8,375 | Draugr | The draugr or draug (Old Norse: draugr, plural draugar; modern Icelandic: draugur, Faroese: dreygur and Danish, Swedish, and Norwegian: draug) is an undead creature from the Scandinavian saga literature and folktales.
Commentators extend the term draugr to the undead in medieval literature, even if it is never explicitly referred to as such in the text, and designated them rather as a haugbúi ("barrow-dweller") or an aptrganga, literally "again-walker" (Icelandic: afturganga).
Draugar live in their graves or royal palaces, often guarding treasure buried with them in their burial mound. They are revenants, or animated corpses with a corporeal body, rather than ghosts which possess intangible spiritual bodies.
Old Norse draugr is defined as "a ghost, spirit, esp. the dead inhabitant of a cairn". Often the draugr is regarded not so much as a ghost but a revenant, i.e., the reanimated corpse of the deceased inside the burial mound (as in the example of Kárr inn gamli in Grettis saga).
The draugr was referred to as "barrow-wight" in the 1869 translation of Grettis saga, long before J. R. R. Tolkien employed this term in his novels, though "barrow-wight" is actually a rendering of haugbúinn (literally the ‘howe-dweller’), otherwise translated as "barrow-dweller".
In Swedish, draug is a modern loanword from West Norse, as the native Swedish form drög has acquired the meaning of "a pale, ineffectual, and slow-minded person that drags himself along".
The word is hypothetically traced to Proto-Indo European stem *dʰrowgʰos "phantom", from *dʰrewgʰ- "deceive" (see also Avestan "druj").
Beings in British folklore such as "shag-boys" and "hogboons" derive their names from Old Norse: haugbui.
Unlike Kárr inn gamli (Kar the Old) in Grettis saga, who is specifically called a draugr, Glámr the ghost in the same saga is never explicitly called a draugr in the text, though called a "troll" in it. Yet Glámr is still routinely referred to as a draugr by modern scholars.
Beings not specifically called draugar, but actually only referred to as aptrgǫngur (‘revenants’, pl. of aptrganga) and reimleikar (‘haunting’) in these medieval sagas are still commonly discussed as a draugr in various scholarly works, or the draugar and the haugbúar are lumped into one.
A further caveat is that the application of the term draugr may not necessarily follow what the term might have meant in the strict sense during medieval times, but rather follow a modern definition or notion of draugr, specifically such ghostly beings (by whatever names they are called) that occur in Icelandic folktales categorized as "Draugasögur" in Jón Árnason's collection, based on the classification groundwork laid by Konrad Maurer.
The draugr is a "corporeal ghost" with a physical tangible body and not an "imago", and in tales it is often delivered a "second death" by destruction of the enlivened corpse.
The draugr has also been conceived of as a type of "vampire" by folktale anthologist Andrew Lang in late 1897, with the idea further pursued by more modern commentators. The focus here is not on blood-sucking, which is not attested for the draugr, but rather, contagiousness or transmittable nature of vampirism, that is to say, how a vampire begets another by turning his or her attack victim into one of his own kind. Sometimes the chain of contagion becomes an outbreak, e.g., the case of Þórólfr bægifótr (Thorolf Lame-foot or Twist-Foot), and even called an "epidemic" regarding Þórgunna (Thorgunna).
A more speculative case of vampirism is that of Glámr, who was asked to tend sheep for a haunted farmstead and was subsequently found dead with his neck and every bone in his body broken. It has been surmised by commentators that Glámr by "contamination" was turned into an undead (draugr) by whatever being was haunting the farm.
Draugar usually possessed superhuman strength, and were "generally hideous to look at", bearing a necrotic black or blue color, and were associated with a "reek of decay" or more precisely inhabited haunts that often issued foul stench.
The draugar were said to be either hel-blár ("death-blue") or nár-fölr ("corpse-pale"). Glámr when found dead was described as "blár sem Hel en digr sem naut (black as hell and bloated to the size of a bull)". Þórólfr Lame-foot, when lying dormant, looked "uncorrupted" and also "was black as death [i.e., bruised black and blue] and swollen to the size of an ox". The close similarity of these descriptions have been noted. Laxdæla saga describes how bones were dug up belonging to a dead sorceress who had appeared in dreams, and they were "blue and evil looking".
Þráinn (Thrain) the berserker of Valland "turned himself into a troll" in Hrómundar saga Gripssonar was a fiend (dólgr) which was "black and huge.. roaring loudly and blowing fire", and moreover, possessed long scratching claws, and the claws stuck in the neck, prompting the hero Hrómundr to refer to the dragur as a sort of cat (Old Norse: kattakyn). The possession of long claws features also in the case of another revenant, Ásviðr (Aswitus) who came to life in the night and attacked his foster-brother Ásmundr (Asmundus) with them, scratching his face and tearing one of his ears.
Draugrs often give off a morbid stench, not unlike the smell of a decaying body. The mound where Kárr the Old was entombed reeked horribly. In Harðar saga Hörðr Grímkelsson’s two underlings die even before entering Sóti the Viking's mound, due to the "gust and stink (ódaun)" wafting out of it. When enraged Þráinn filled the barrow with an "evil reek."
Draugar are noted for having numerous magical abilities (referred to as trollskap) resembling those of living witches and wizards, such as shape-shifting, controlling the weather, and seeing into the future.
The undead Víga-Hrappr Sumarliðason (Killer-Hrapp) of Laxdaela saga, unlike the typical guardian of a treasure hoard, does not stay put in his burial place but roams around his farmstead of Hrappstaðir, menacing the living. Víga-Hrappr's ghost, it has been suggested, was capable of transforming into the seal with human-like eyes which appeared before Þorsteinn svarti/surt (Thorsteinn the Black) sailing by ship, and was responsible for the sinking of the ship to prevent the family from reaching Hrappstaðir. The ability to shape-shift has been ascribed to Icelandic ghosts generally, particularly into the shape of a seal.
A draugr in Icelandic folktales collected in the modern age can also change into a great flayed bull, a grey horse with a broken back but no ears or tail, and a cat that would sit upon a sleeper's chest and grow steadily heavier until their victim suffocated.
Draugar have the ability to enter into the dreams of the living, and they will frequently leave a gift behind so that "the living person may be assured of the tangible nature of the visit". Draugar also have the ability to curse a victim, as shown in the Grettis saga, where Grettir is cursed to be unable to become any stronger. Draugar also brought disease to a village and could create temporary darkness in daylight hours. They preferred to be active during the night, although they did not appear to be vulnerable to sunlight like some other revenants. Draugr can also kill people with bad luck.
A draugr's presence might be shown by a great light that glowed from the mound like foxfire. This fire would form a barrier between the land of the living and the land of the dead.
The undead Víga-Hrappr exhibited the ability to sink into the ground to escape from Óláfr Hǫskuldsson the Peacock.
Some draugar are immune to weapons, and only a hero has the strength and courage needed to stand up to so formidable an opponent. In legends, the hero would often have to wrestle the draugr back to his grave, thereby defeating him, since weapons would do no good. A good example of this is found in Hrómundar saga Gripssonar. Iron could injure a draugr, as is the case with many supernatural creatures, although it would not be sufficient to stop it. Sometimes the hero is required to dispose of the body in unconventional ways. The preferred method is to cut off the draugr's head, burn the body, and dump the ashes in the sea—the emphasis being on making absolutely sure that the draugr was dead and gone.
Any mean, nasty, or greedy person can become a draugr. As Ármann Jakobsson notes, "most medieval Icelandic ghosts are evil or marginal people. If not dissatisfied or evil, they are unpopular".
The draugr's motivation was primarily envy and greed. Greed causes it to viciously attack any would-be grave robbers, but the draugr also expresses an innate envy of the living stemming from a longing for the things of life which it once had. They also exhibit an immense and nearly insatiable appetite, as shown in the encounter of Aran and Asmund, sword brothers who made an oath that, if one should die, the other would sit vigil with him for three days inside the burial mound. When Aran died, Asmund brought his own possessions into the barrow—banners, armor, hawk, hound, and horse—then set himself to wait the three days:
During the first night, Aran got up from his chair and killed the hawk and hound and ate them. On the second night he got up again from his chair, and killed the horse and tore it into pieces; then he took great bites at the horse-flesh with his teeth, the blood streaming down from his mouth all the while he was eating…. The third night Asmund became very drowsy, and the first thing he knew, Aran had got him by the ears and torn them off.
The draugr's victims were not limited to trespassers in its home. The roaming undead devastated livestock by running the animals to death either by riding them or pursuing them in some hideous, half-flayed form. Shepherds' duties kept them outdoors at night, and they were particular targets for the hunger and hatred of the undead:
The oxen which had been used to haul Thorolf's body were ridden to death by demons, and every single beast that came near his grave went raving mad and howled itself to death. The shepherd at Hvamm often came racing home with Thorolf after him. One day that Fall neither sheep nor shepherd came back to the farm.
Animals feeding near the grave of a draugr might be driven mad by the creature's influence. They may also die from being driven mad. Thorolf, for example, caused birds to drop dead when they flew over his bowl barrow.
The main indication that a deceased person will become a draugr is that the corpse is not in a horizontal position but is found standing upright (Víga-Hrappr), or in a sitting position (Þórólfr), indicating that the dead might return. Ármann Jakobsson suggests further that breaking the draugr's posture is a necessary or helpful step in destroying the draugr, but this is fraught with the risk of being inflicted with the evil eye, whether this is explicitly told in the case of Grettir who receives the curse from Glámr, or only implied in the case of Þórólfr, whose son warns the others to beware while they unbend Þórólfr's seated posture.
The revenant draugr needing to be decapitated in order to incapacitate them from further hauntings is a common theme in the family sagas.
Traditionally, a pair of open iron scissors was placed on the chest of the recently deceased, and straws or twigs might be hidden among their clothes. The big toes were tied together or needles were driven through the soles of the feet in order to keep the dead from being able to walk. Tradition also held that the coffin should be lifted and lowered in three different directions as it was carried from the house to confuse a possible draugr's sense of direction.
The most effective means of preventing the return of the dead was believed to be a corpse door, a special door through which the corpse was carried feet-first with people surrounding it so that the corpse couldn't see where it was going. The door was then bricked up to prevent a return. It is speculated that this belief began in Denmark and spread throughout the Norse culture, founded on the idea that the dead could only leave through the way they entered.
In Eyrbyggja saga, draugar are driven off by holding a "door-doom". One by one, they are summoned to the door-doom and given judgment and forced out of the home by this legal method. The home was then purified with holy water to ensure that they never came back.
A variation of the draugr is the haugbui (from Old Norse haugr' "howe, barrow, tumulus") which was a mound-dweller, the dead body living on within its tomb. The notable difference between the two was that the haugbui is unable to leave its grave site and only attacks those who trespass upon their territory.
The haugbui was rarely found far from its burial place and is a type of undead commonly found in Norse sagas. The creature is said to either swim alongside boats or sail around them in a partially submerged vessel, always on their own. In some accounts, witnesses portray them as shapeshifters who take on the appearance of seaweed or moss-covered stones on the shoreline.
One of the best-known draugar is Glámr, who is defeated by the hero in Grettis saga. After Glámr dies on Christmas Eve, "people became aware that Glámr was not resting in peace. He wrought such havoc that some people fainted at the sight of him, while others went out of their minds". After a battle, Grettir eventually gets Glámr on his back. Just before Grettir kills him, Glámr curses Grettir because "Glámr was endowed with more evil force than most other ghosts", and thus he was able to speak and leave Grettir with his curse after his death.
A somewhat ambivalent, alternative view of the draugr is presented by the example of Gunnar Hámundarson in Njáls saga: "It seemed as though the howe was agape, and that Gunnar had turned within the howe to look upwards at the moon. They thought that they saw four lights within the howe, but not a shadow to be seen. Then they saw that Gunnar was merry, with a joyful face."
In the Eyrbyggja saga, a shepherd is assaulted by a blue-black draugr. The shepherd's neck is broken during the ensuing scuffle. The shepherd rises the next night as a draugr.
In more recent Scandinavian folklore, the draug (the modern spelling used in Denmark, Norway, and Sweden) is a supernatural being that occurs in legends along the coast of Norway. Draugen was originally a dead person who either lived in the mound (in Norse called haugbúi) or went out to haunt the living. In later folklore, it became common to limit the figure to a ghost of a dead fisherman who had drifted at sea, and who was not buried in Christian soil. It was said that he wore a leather jacket or was dressed in oilskin, but had a seaweed vase for his head. He sailed in a half-boat with blocked sails (the Norwegian municipality of Bø, Nordland has the half-boat in its coat-of-arms) and announced death for those who saw him or even wanted to pull them down. This trait is common in the northernmost part of Norway, where life and culture was based on fishing more than anywhere else. The reason for this may be that the fishermen often drowned in great numbers, and the stories of restless dead coming in from sea were more common in the north than any other region of the country.
A recorded legend from Trøndelag tells how a cadaver lying on a beach became the object of a quarrel between the two types of draug (headless and seaweed-headed). A similar source even tells of a third type, the gleip, known to hitch themselves to sailors walking ashore and make them slip on the wet rocks.
But, though the draug usually presages death, there is an amusing account in Northern Norway of a northerner who managed to outwit him:
It was Christmas Eve, and Ola went down to his boathouse to get the keg of brandy he had bought for the holidays. When he got in, he noticed a draugr sitting on the keg, staring out to sea. Ola, with great presence of mind and great bravery (it might not be amiss to state that he already had done some drinking), tiptoed up behind the draugr and struck him sharply in the small of the back, so that he went flying out through the window, with sparks hissing around him as he hit the water. Ola knew he had no time to lose, so he set off at a great rate, running through the churchyard which lay between his home and the boathouse. As he ran, he cried, "Up, all you Christian souls, and help me!" Then he heard the sound of fighting between the ghosts and the draugr, who were battling each other with coffin boards and bunches of seaweed. The next morning, when people came to church, the whole yard was strewn with coffin covers, boat boards, and seaweed. After the fight, which the ghosts won, the draugr never came back to that district.
The modern and popular connection between the draug and the sea can be traced back to authors like Jonas Lie and Regine Nordmann, whose works include several books of fairy tales, as well as the drawings of Theodor Kittelsen, who spent some years living in Svolvær. Up north, the tradition of sea-draugs is especially vivid.
Arne Garborg describes land-draugs coming fresh from the graveyards, and the term draug is even used of vampires. The notion of draugs who live in the mountains is present in the poetic works of Henrik Ibsen (Peer Gynt), and Aasmund Olavsson Vinje. The Nynorsk translation of The Lord of the Rings used the term for both Nazgûl and the dead men of Dunharrow. Tolkien's barrow-wights bear obvious similarity to, and were inspired by the haugbúi.
In The Elder Scrolls video game series, draugr are the undead mummified corpses of fallen warriors that inhabit the ancient burial sites of a Nordic-inspired race of man. These draugr behave more like haugbúi than traditional draugr. They first appeared in the Bloodmoon expansion to The Elder Scrolls III: Morrowind, and would later go on to appear all throughout The Elder Scrolls V: Skyrim. Draugr are a common enemy, the first encountered by the player, in the 2018 video game God of War, with a variety of different powers and abilities. In 2019, a spaceship named Draugur was added to the game Eve Online, as the command destroyer of the Triglavian faction. Draugr appear as an enemies in the 2021 early access game Valheim, where they take the more recent, seaweed version of the Draug.
In Draug (film), a group of Viking warriors encounter the draugr while searching for a missing person inside a huge forest. The draugr are depicted as blue-black animated corpses wielding many magical abilities.
In the movie The Northman, Amleth enters a burial mound, in search of a magical sword named "Draugr". Inside the grave chamber Amleth encounters an undead Mound Dweller (draugr), who he has to fight in order to obtain the blade.
Season two episode two of Hilda, entitled "The Draugen," involved draugen as the ghosts of sailors who died at sea. While their form was ghostly, the captain was able to wear a coat, and had a shock of seaweed for hair.
The exoplanet PSR B1257+12 A has been named "Draugr". | [
{
"paragraph_id": 0,
"text": "The draugr or draug (Old Norse: draugr, plural draugar; modern Icelandic: draugur, Faroese: dreygur and Danish, Swedish, and Norwegian: draug) is an undead creature from the Scandinavian saga literature and folktales.",
"title": ""
},
{
"paragraph_id": 1,
"text": "Commentators extend the term draugr to the undead in medieval literature, even if it is never explicitly referred to as such in the text, and designated them rather as a haugbúi (\"barrow-dweller\") or an aptrganga, literally \"again-walker\" (Icelandic: afturganga).",
"title": ""
},
{
"paragraph_id": 2,
"text": "Draugar live in their graves or royal palaces, often guarding treasure buried with them in their burial mound. They are revenants, or animated corpses with a corporeal body, rather than ghosts which possess intangible spiritual bodies.",
"title": "Overview"
},
{
"paragraph_id": 3,
"text": "Old Norse draugr is defined as \"a ghost, spirit, esp. the dead inhabitant of a cairn\". Often the draugr is regarded not so much as a ghost but a revenant, i.e., the reanimated corpse of the deceased inside the burial mound (as in the example of Kárr inn gamli in Grettis saga).",
"title": "Terminology"
},
{
"paragraph_id": 4,
"text": "The draugr was referred to as \"barrow-wight\" in the 1869 translation of Grettis saga, long before J. R. R. Tolkien employed this term in his novels, though \"barrow-wight\" is actually a rendering of haugbúinn (literally the ‘howe-dweller’), otherwise translated as \"barrow-dweller\".",
"title": "Terminology"
},
{
"paragraph_id": 5,
"text": "In Swedish, draug is a modern loanword from West Norse, as the native Swedish form drög has acquired the meaning of \"a pale, ineffectual, and slow-minded person that drags himself along\".",
"title": "Terminology"
},
{
"paragraph_id": 6,
"text": "The word is hypothetically traced to Proto-Indo European stem *dʰrowgʰos \"phantom\", from *dʰrewgʰ- \"deceive\" (see also Avestan \"druj\").",
"title": "Terminology"
},
{
"paragraph_id": 7,
"text": "Beings in British folklore such as \"shag-boys\" and \"hogboons\" derive their names from Old Norse: haugbui.",
"title": "Terminology"
},
{
"paragraph_id": 8,
"text": "Unlike Kárr inn gamli (Kar the Old) in Grettis saga, who is specifically called a draugr, Glámr the ghost in the same saga is never explicitly called a draugr in the text, though called a \"troll\" in it. Yet Glámr is still routinely referred to as a draugr by modern scholars.",
"title": "Terminology"
},
{
"paragraph_id": 9,
"text": "Beings not specifically called draugar, but actually only referred to as aptrgǫngur (‘revenants’, pl. of aptrganga) and reimleikar (‘haunting’) in these medieval sagas are still commonly discussed as a draugr in various scholarly works, or the draugar and the haugbúar are lumped into one.",
"title": "Terminology"
},
{
"paragraph_id": 10,
"text": "A further caveat is that the application of the term draugr may not necessarily follow what the term might have meant in the strict sense during medieval times, but rather follow a modern definition or notion of draugr, specifically such ghostly beings (by whatever names they are called) that occur in Icelandic folktales categorized as \"Draugasögur\" in Jón Árnason's collection, based on the classification groundwork laid by Konrad Maurer.",
"title": "Terminology"
},
{
"paragraph_id": 11,
"text": "The draugr is a \"corporeal ghost\" with a physical tangible body and not an \"imago\", and in tales it is often delivered a \"second death\" by destruction of the enlivened corpse.",
"title": "Overall classification"
},
{
"paragraph_id": 12,
"text": "The draugr has also been conceived of as a type of \"vampire\" by folktale anthologist Andrew Lang in late 1897, with the idea further pursued by more modern commentators. The focus here is not on blood-sucking, which is not attested for the draugr, but rather, contagiousness or transmittable nature of vampirism, that is to say, how a vampire begets another by turning his or her attack victim into one of his own kind. Sometimes the chain of contagion becomes an outbreak, e.g., the case of Þórólfr bægifótr (Thorolf Lame-foot or Twist-Foot), and even called an \"epidemic\" regarding Þórgunna (Thorgunna).",
"title": "Overall classification"
},
{
"paragraph_id": 13,
"text": "A more speculative case of vampirism is that of Glámr, who was asked to tend sheep for a haunted farmstead and was subsequently found dead with his neck and every bone in his body broken. It has been surmised by commentators that Glámr by \"contamination\" was turned into an undead (draugr) by whatever being was haunting the farm.",
"title": "Overall classification"
},
{
"paragraph_id": 14,
"text": "Draugar usually possessed superhuman strength, and were \"generally hideous to look at\", bearing a necrotic black or blue color, and were associated with a \"reek of decay\" or more precisely inhabited haunts that often issued foul stench.",
"title": "Physical traits"
},
{
"paragraph_id": 15,
"text": "The draugar were said to be either hel-blár (\"death-blue\") or nár-fölr (\"corpse-pale\"). Glámr when found dead was described as \"blár sem Hel en digr sem naut (black as hell and bloated to the size of a bull)\". Þórólfr Lame-foot, when lying dormant, looked \"uncorrupted\" and also \"was black as death [i.e., bruised black and blue] and swollen to the size of an ox\". The close similarity of these descriptions have been noted. Laxdæla saga describes how bones were dug up belonging to a dead sorceress who had appeared in dreams, and they were \"blue and evil looking\".",
"title": "Physical traits"
},
{
"paragraph_id": 16,
"text": "Þráinn (Thrain) the berserker of Valland \"turned himself into a troll\" in Hrómundar saga Gripssonar was a fiend (dólgr) which was \"black and huge.. roaring loudly and blowing fire\", and moreover, possessed long scratching claws, and the claws stuck in the neck, prompting the hero Hrómundr to refer to the dragur as a sort of cat (Old Norse: kattakyn). The possession of long claws features also in the case of another revenant, Ásviðr (Aswitus) who came to life in the night and attacked his foster-brother Ásmundr (Asmundus) with them, scratching his face and tearing one of his ears.",
"title": "Physical traits"
},
{
"paragraph_id": 17,
"text": "Draugrs often give off a morbid stench, not unlike the smell of a decaying body. The mound where Kárr the Old was entombed reeked horribly. In Harðar saga Hörðr Grímkelsson’s two underlings die even before entering Sóti the Viking's mound, due to the \"gust and stink (ódaun)\" wafting out of it. When enraged Þráinn filled the barrow with an \"evil reek.\"",
"title": "Physical traits"
},
{
"paragraph_id": 18,
"text": "Draugar are noted for having numerous magical abilities (referred to as trollskap) resembling those of living witches and wizards, such as shape-shifting, controlling the weather, and seeing into the future.",
"title": "Magical abilities"
},
{
"paragraph_id": 19,
"text": "The undead Víga-Hrappr Sumarliðason (Killer-Hrapp) of Laxdaela saga, unlike the typical guardian of a treasure hoard, does not stay put in his burial place but roams around his farmstead of Hrappstaðir, menacing the living. Víga-Hrappr's ghost, it has been suggested, was capable of transforming into the seal with human-like eyes which appeared before Þorsteinn svarti/surt (Thorsteinn the Black) sailing by ship, and was responsible for the sinking of the ship to prevent the family from reaching Hrappstaðir. The ability to shape-shift has been ascribed to Icelandic ghosts generally, particularly into the shape of a seal.",
"title": "Magical abilities"
},
{
"paragraph_id": 20,
"text": "A draugr in Icelandic folktales collected in the modern age can also change into a great flayed bull, a grey horse with a broken back but no ears or tail, and a cat that would sit upon a sleeper's chest and grow steadily heavier until their victim suffocated.",
"title": "Magical abilities"
},
{
"paragraph_id": 21,
"text": "Draugar have the ability to enter into the dreams of the living, and they will frequently leave a gift behind so that \"the living person may be assured of the tangible nature of the visit\". Draugar also have the ability to curse a victim, as shown in the Grettis saga, where Grettir is cursed to be unable to become any stronger. Draugar also brought disease to a village and could create temporary darkness in daylight hours. They preferred to be active during the night, although they did not appear to be vulnerable to sunlight like some other revenants. Draugr can also kill people with bad luck.",
"title": "Magical abilities"
},
{
"paragraph_id": 22,
"text": "A draugr's presence might be shown by a great light that glowed from the mound like foxfire. This fire would form a barrier between the land of the living and the land of the dead.",
"title": "Magical abilities"
},
{
"paragraph_id": 23,
"text": "The undead Víga-Hrappr exhibited the ability to sink into the ground to escape from Óláfr Hǫskuldsson the Peacock.",
"title": "Magical abilities"
},
{
"paragraph_id": 24,
"text": "Some draugar are immune to weapons, and only a hero has the strength and courage needed to stand up to so formidable an opponent. In legends, the hero would often have to wrestle the draugr back to his grave, thereby defeating him, since weapons would do no good. A good example of this is found in Hrómundar saga Gripssonar. Iron could injure a draugr, as is the case with many supernatural creatures, although it would not be sufficient to stop it. Sometimes the hero is required to dispose of the body in unconventional ways. The preferred method is to cut off the draugr's head, burn the body, and dump the ashes in the sea—the emphasis being on making absolutely sure that the draugr was dead and gone.",
"title": "Magical abilities"
},
{
"paragraph_id": 25,
"text": "Any mean, nasty, or greedy person can become a draugr. As Ármann Jakobsson notes, \"most medieval Icelandic ghosts are evil or marginal people. If not dissatisfied or evil, they are unpopular\".",
"title": "Behaviour and character"
},
{
"paragraph_id": 26,
"text": "The draugr's motivation was primarily envy and greed. Greed causes it to viciously attack any would-be grave robbers, but the draugr also expresses an innate envy of the living stemming from a longing for the things of life which it once had. They also exhibit an immense and nearly insatiable appetite, as shown in the encounter of Aran and Asmund, sword brothers who made an oath that, if one should die, the other would sit vigil with him for three days inside the burial mound. When Aran died, Asmund brought his own possessions into the barrow—banners, armor, hawk, hound, and horse—then set himself to wait the three days:",
"title": "Behaviour and character"
},
{
"paragraph_id": 27,
"text": "During the first night, Aran got up from his chair and killed the hawk and hound and ate them. On the second night he got up again from his chair, and killed the horse and tore it into pieces; then he took great bites at the horse-flesh with his teeth, the blood streaming down from his mouth all the while he was eating…. The third night Asmund became very drowsy, and the first thing he knew, Aran had got him by the ears and torn them off.",
"title": "Behaviour and character"
},
{
"paragraph_id": 28,
"text": "The draugr's victims were not limited to trespassers in its home. The roaming undead devastated livestock by running the animals to death either by riding them or pursuing them in some hideous, half-flayed form. Shepherds' duties kept them outdoors at night, and they were particular targets for the hunger and hatred of the undead:",
"title": "Behaviour and character"
},
{
"paragraph_id": 29,
"text": "The oxen which had been used to haul Thorolf's body were ridden to death by demons, and every single beast that came near his grave went raving mad and howled itself to death. The shepherd at Hvamm often came racing home with Thorolf after him. One day that Fall neither sheep nor shepherd came back to the farm.",
"title": "Behaviour and character"
},
{
"paragraph_id": 30,
"text": "Animals feeding near the grave of a draugr might be driven mad by the creature's influence. They may also die from being driven mad. Thorolf, for example, caused birds to drop dead when they flew over his bowl barrow.",
"title": "Behaviour and character"
},
{
"paragraph_id": 31,
"text": "The main indication that a deceased person will become a draugr is that the corpse is not in a horizontal position but is found standing upright (Víga-Hrappr), or in a sitting position (Þórólfr), indicating that the dead might return. Ármann Jakobsson suggests further that breaking the draugr's posture is a necessary or helpful step in destroying the draugr, but this is fraught with the risk of being inflicted with the evil eye, whether this is explicitly told in the case of Grettir who receives the curse from Glámr, or only implied in the case of Þórólfr, whose son warns the others to beware while they unbend Þórólfr's seated posture.",
"title": "Behaviour and character"
},
{
"paragraph_id": 32,
"text": "The revenant draugr needing to be decapitated in order to incapacitate them from further hauntings is a common theme in the family sagas.",
"title": "Behaviour and character"
},
{
"paragraph_id": 33,
"text": "Traditionally, a pair of open iron scissors was placed on the chest of the recently deceased, and straws or twigs might be hidden among their clothes. The big toes were tied together or needles were driven through the soles of the feet in order to keep the dead from being able to walk. Tradition also held that the coffin should be lifted and lowered in three different directions as it was carried from the house to confuse a possible draugr's sense of direction.",
"title": "Behaviour and character"
},
{
"paragraph_id": 34,
"text": "The most effective means of preventing the return of the dead was believed to be a corpse door, a special door through which the corpse was carried feet-first with people surrounding it so that the corpse couldn't see where it was going. The door was then bricked up to prevent a return. It is speculated that this belief began in Denmark and spread throughout the Norse culture, founded on the idea that the dead could only leave through the way they entered.",
"title": "Behaviour and character"
},
{
"paragraph_id": 35,
"text": "In Eyrbyggja saga, draugar are driven off by holding a \"door-doom\". One by one, they are summoned to the door-doom and given judgment and forced out of the home by this legal method. The home was then purified with holy water to ensure that they never came back.",
"title": "Behaviour and character"
},
{
"paragraph_id": 36,
"text": "A variation of the draugr is the haugbui (from Old Norse haugr' \"howe, barrow, tumulus\") which was a mound-dweller, the dead body living on within its tomb. The notable difference between the two was that the haugbui is unable to leave its grave site and only attacks those who trespass upon their territory.",
"title": "Similar beings"
},
{
"paragraph_id": 37,
"text": "The haugbui was rarely found far from its burial place and is a type of undead commonly found in Norse sagas. The creature is said to either swim alongside boats or sail around them in a partially submerged vessel, always on their own. In some accounts, witnesses portray them as shapeshifters who take on the appearance of seaweed or moss-covered stones on the shoreline.",
"title": "Similar beings"
},
{
"paragraph_id": 38,
"text": "One of the best-known draugar is Glámr, who is defeated by the hero in Grettis saga. After Glámr dies on Christmas Eve, \"people became aware that Glámr was not resting in peace. He wrought such havoc that some people fainted at the sight of him, while others went out of their minds\". After a battle, Grettir eventually gets Glámr on his back. Just before Grettir kills him, Glámr curses Grettir because \"Glámr was endowed with more evil force than most other ghosts\", and thus he was able to speak and leave Grettir with his curse after his death.",
"title": "Folklore"
},
{
"paragraph_id": 39,
"text": "A somewhat ambivalent, alternative view of the draugr is presented by the example of Gunnar Hámundarson in Njáls saga: \"It seemed as though the howe was agape, and that Gunnar had turned within the howe to look upwards at the moon. They thought that they saw four lights within the howe, but not a shadow to be seen. Then they saw that Gunnar was merry, with a joyful face.\"",
"title": "Folklore"
},
{
"paragraph_id": 40,
"text": "In the Eyrbyggja saga, a shepherd is assaulted by a blue-black draugr. The shepherd's neck is broken during the ensuing scuffle. The shepherd rises the next night as a draugr.",
"title": "Folklore"
},
{
"paragraph_id": 41,
"text": "In more recent Scandinavian folklore, the draug (the modern spelling used in Denmark, Norway, and Sweden) is a supernatural being that occurs in legends along the coast of Norway. Draugen was originally a dead person who either lived in the mound (in Norse called haugbúi) or went out to haunt the living. In later folklore, it became common to limit the figure to a ghost of a dead fisherman who had drifted at sea, and who was not buried in Christian soil. It was said that he wore a leather jacket or was dressed in oilskin, but had a seaweed vase for his head. He sailed in a half-boat with blocked sails (the Norwegian municipality of Bø, Nordland has the half-boat in its coat-of-arms) and announced death for those who saw him or even wanted to pull them down. This trait is common in the northernmost part of Norway, where life and culture was based on fishing more than anywhere else. The reason for this may be that the fishermen often drowned in great numbers, and the stories of restless dead coming in from sea were more common in the north than any other region of the country.",
"title": "Folklore"
},
{
"paragraph_id": 42,
"text": "A recorded legend from Trøndelag tells how a cadaver lying on a beach became the object of a quarrel between the two types of draug (headless and seaweed-headed). A similar source even tells of a third type, the gleip, known to hitch themselves to sailors walking ashore and make them slip on the wet rocks.",
"title": "Folklore"
},
{
"paragraph_id": 43,
"text": "But, though the draug usually presages death, there is an amusing account in Northern Norway of a northerner who managed to outwit him:",
"title": "Folklore"
},
{
"paragraph_id": 44,
"text": "It was Christmas Eve, and Ola went down to his boathouse to get the keg of brandy he had bought for the holidays. When he got in, he noticed a draugr sitting on the keg, staring out to sea. Ola, with great presence of mind and great bravery (it might not be amiss to state that he already had done some drinking), tiptoed up behind the draugr and struck him sharply in the small of the back, so that he went flying out through the window, with sparks hissing around him as he hit the water. Ola knew he had no time to lose, so he set off at a great rate, running through the churchyard which lay between his home and the boathouse. As he ran, he cried, \"Up, all you Christian souls, and help me!\" Then he heard the sound of fighting between the ghosts and the draugr, who were battling each other with coffin boards and bunches of seaweed. The next morning, when people came to church, the whole yard was strewn with coffin covers, boat boards, and seaweed. After the fight, which the ghosts won, the draugr never came back to that district.",
"title": "Folklore"
},
{
"paragraph_id": 45,
"text": "The modern and popular connection between the draug and the sea can be traced back to authors like Jonas Lie and Regine Nordmann, whose works include several books of fairy tales, as well as the drawings of Theodor Kittelsen, who spent some years living in Svolvær. Up north, the tradition of sea-draugs is especially vivid.",
"title": "Folklore"
},
{
"paragraph_id": 46,
"text": "Arne Garborg describes land-draugs coming fresh from the graveyards, and the term draug is even used of vampires. The notion of draugs who live in the mountains is present in the poetic works of Henrik Ibsen (Peer Gynt), and Aasmund Olavsson Vinje. The Nynorsk translation of The Lord of the Rings used the term for both Nazgûl and the dead men of Dunharrow. Tolkien's barrow-wights bear obvious similarity to, and were inspired by the haugbúi.",
"title": "Folklore"
},
{
"paragraph_id": 47,
"text": "In The Elder Scrolls video game series, draugr are the undead mummified corpses of fallen warriors that inhabit the ancient burial sites of a Nordic-inspired race of man. These draugr behave more like haugbúi than traditional draugr. They first appeared in the Bloodmoon expansion to The Elder Scrolls III: Morrowind, and would later go on to appear all throughout The Elder Scrolls V: Skyrim. Draugr are a common enemy, the first encountered by the player, in the 2018 video game God of War, with a variety of different powers and abilities. In 2019, a spaceship named Draugur was added to the game Eve Online, as the command destroyer of the Triglavian faction. Draugr appear as an enemies in the 2021 early access game Valheim, where they take the more recent, seaweed version of the Draug.",
"title": "Folklore"
},
{
"paragraph_id": 48,
"text": "In Draug (film), a group of Viking warriors encounter the draugr while searching for a missing person inside a huge forest. The draugr are depicted as blue-black animated corpses wielding many magical abilities.",
"title": "Folklore"
},
{
"paragraph_id": 49,
"text": "In the movie The Northman, Amleth enters a burial mound, in search of a magical sword named \"Draugr\". Inside the grave chamber Amleth encounters an undead Mound Dweller (draugr), who he has to fight in order to obtain the blade.",
"title": "Folklore"
},
{
"paragraph_id": 50,
"text": "Season two episode two of Hilda, entitled \"The Draugen,\" involved draugen as the ghosts of sailors who died at sea. While their form was ghostly, the captain was able to wear a coat, and had a shock of seaweed for hair.",
"title": "Folklore"
},
{
"paragraph_id": 51,
"text": "The exoplanet PSR B1257+12 A has been named \"Draugr\".",
"title": "Folklore"
}
] | The draugr or draug is an undead creature from the Scandinavian saga literature and folktales. Commentators extend the term draugr to the undead in medieval literature, even if it is never explicitly referred to as such in the text, and designated them rather as a haugbúi ("barrow-dweller") or an aptrganga, literally "again-walker". | 2001-09-27T15:32:19Z | 2023-12-07T08:04:07Z | [
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] | https://en.wikipedia.org/wiki/Draugr |
8,376 | Day | A day is the time period of a full rotation of the Earth with respect to the Sun. On average, this is 24 hours (86,400 seconds). As a day passes at a given location it experiences morning, noon, afternoon, evening, and night. This daily cycle drives circadian rhythms in many organisms, which are vital to many life processes.
A collection of sequential days is organized into calendars as dates, almost always into weeks, months and years. A solar calendar organizes dates based on the Sun's annual cycle, giving consistent start dates for the four seasons from year to year. A lunar calendar organizes dates based on the Moon's lunar phase.
In common usage, a day starts at midnight, written as 00:00 or 12:00 am in 24- or 12-hour clocks, respectively. Because the time of midnight varies between locations, time zones are set up to facilitate the use of a uniform standard time. Other conventions are sometimes used, for example the Jewish religious calendar counts days from sunset to sunset, so the Jewish Sabbath begins at sundown on Friday. In astronomy, a day begins at noon so that observations throughout a single night are recorded as happening on the same day.
In specific applications, the definition of a day is slightly modified, such as in the SI day (exactly 86,400 seconds) used for computers and standards keeping, local mean time accounting of the Earth's natural fluctuation of a solar day, and stellar day and sidereal day (using the celestial sphere) used for astronomy. In most countries outside of the tropics, daylight saving time is practiced, and each year there will be one 23-hour civil day and one 25-hour civil day. Due to slight variations in the rotation of the Earth, there are rare times when a leap second will get inserted at the end of a UTC day, and so while almost all days have a duration of 86,400 seconds, there are these exceptional cases of a day with 86,401 seconds (in the half-century spanning 1972 through 2022, there have been a total of 27 leap seconds that have been inserted, so roughly once every other year).
The term comes from the Old English term dæġ (/dæj/), with its cognates such as dagur in Icelandic, Tag in German, and dag in Norwegian, Danish, Swedish and Dutch – all stemming from a Proto-Germanic root *dagaz. As of October 17, 2015, day is the 205th most common word in US English, and the 210th most common in UK English.
Several definitions of this universal human concept are used according to context, need, and convenience. Besides the day of 24 hours (86,400 seconds), the word day is used for several different spans of time based on the rotation of the Earth around its axis. An important one is the solar day, the time it takes for the Sun to return to its culmination point (its highest point in the sky). Due to an orbit's eccentricity, the Sun resides in one of the orbit's foci instead of the middle. Consequently, due to Kepler's second law, the planet travels at different speeds at various positions in its orbit, and thus a solar day is not the same length of time throughout the orbital year. Because the Earth moves along an eccentric orbit around the Sun while the Earth spins on an inclined axis, this period can be up to 7.9 seconds more than (or less than) 24 hours. In recent decades, the average length of a solar day on Earth has been about 86,400.002 seconds (24.000 000 6 hours). There are currently about 365.2421875 solar days in one mean tropical year.
Ancient custom has a new day starting at either the rising or setting of the Sun on the local horizon (Italian reckoning, for example, being 24 hours from sunset, old style). The exact moment of, and the interval between, two sunrises or sunsets depends on the geographical position (longitude and latitude, as well as altitude), and the time of year (as indicated by ancient hemispherical sundials).
A more constant day can be defined by the Sun passing through the local meridian, which happens at local noon (upper culmination) or midnight (lower culmination). The exact moment is dependent on the geographical longitude, and to a lesser extent on the time of the year. The length of such a day is nearly constant (24 hours ± 30 seconds). This is the time as indicated by modern sundials.
A further improvement defines a fictitious mean Sun that moves with constant speed along the celestial equator; the speed is the same as the average speed of the real Sun, but this removes the variation over a year as the Earth moves along its orbit around the Sun (due to both its velocity and its axial tilt).
In terms of Earth's rotation, the average day length is about 360.9856°. A day lasts for more than 360° of rotation because of the Earth's revolution around the Sun. With a full year being slightly more than 360 days, the Earth's daily orbit around the Sun is slightly less than 1°, so the day is slightly less than 361° of rotation.
Elsewhere in the Solar System or other parts of the universe, a day is a full rotation of other large astronomical objects with respect to its star.
For civil purposes, a common clock time is typically defined for an entire region based on the local mean solar time at a central meridian. Such time zones began to be adopted about the middle of the 19th century when railroads with regularly occurring schedules came into use, with most major countries having adopted them by 1929. As of 2015, throughout the world, 40 such zones are now in use: the central zone, from which all others are defined as offsets, is known as UTC±00, which uses Coordinated Universal Time (UTC).
The most common convention starts the civil day at midnight: this is near the time of the lower culmination of the Sun on the central meridian of the time zone. Such a day may be called a calendar day.
A day is commonly divided into 24 hours, with each hour being made up of 60 minutes, and each minute composed of 60 seconds.
A sidereal day or stellar day is the span of time it takes for the Earth to make one entire rotation with respect to the celestial background or a distant star (assumed to be fixed). Measuring a day as such is used in astronomy. A sidereal day is about 4 minutes less than a solar day of 24 hours (23 hours 56 minutes and 4.09 seconds), or 0.99726968 of a solar day of 24 hours. There are about 366.2422 stellar days in one mean tropical year (one stellar day more than the number of solar days).
Besides a stellar day on Earth, other bodies in the Solar System have day times, the durations of these being:
In the International System of Units (SI), a day not an official unit, but is accepted for use with SI. A day, with symbol d, is defined using SI units as 86,400 seconds; the second is the base unit of time in SI units. In 1967–68, during the 13th CGPM (Resolution 1), the International Bureau of Weights and Measures (BIPM) redefined a second as "... the duration of 9,192,631,770 periods of the radiation corresponding to the transition between two hyperfine levels of the ground state of the caesium 133 atom." This makes the SI-based day last exactly 794,243,384,928,000 of those periods.
Various decimal or metric time proposals have been made, but do not redefine the day, and use the day or sidereal day as a base unit. Metric time uses metric prefixes to keep time. It uses the day as the base unit, and smaller units being fractions of a day: a metric hour (deci) is 1⁄10 of a day; a metric minute (milli) is 1⁄1000 of a day; etc. Similarly, in decimal time, the length of a day is static to normal time. A day is also split into 10 hours, and 10 days comprise a décade – the equivalent of a week. 3 décades make a month. Various decimal time proposals which do not redefine the day: Henri de Sarrauton's proposal kept days, and subdivided hours into 100 minutes; in Mendizábal y Tamborel's proposal, the sidereal day was the basic unit, with subdivisions made upon it; and Rey-Pailhade's proposal divided the day 100 cés.
The word refers to various similarly defined ideas, such as:
Mainly due to tidal deceleration – the Moon's gravitational pull slowing down the Earth's rotation – the Earth's rotational period is slowing. Because of the way the second is defined, the mean length of a solar day is now about 86,400.002 seconds, and is increasing by about 2 milliseconds per century.
Since the rotation rate of the Earth is slowing, the length of a SI second fell out of sync with a second derived from the rotational period. This arose the need for leap seconds, which insert extra seconds into Coordinated Universal Time (UTC). Although typically 86,400 SI seconds in duration, a civil day can be either 86,401 or 86,399 SI seconds long on such a day. Other than the two-millisecond variation from tidal deceleration, other factors minutely affect the day's length, which creates an irregularity in the placement of leap seconds. Leap seconds are announced in advance by the International Earth Rotation and Reference Systems Service (IERS), which measures the Earth's rotation and determines whether a leap second is necessary.
Discovered by paleontologist John W. Wells, the day lengths of geological periods have been estimated by measuring sedimentation rings in coral fossils, due to some biological systems being affected by the tide. The length of a day at the Earth's formation is estimated at 6 hours. Arbab I. Arbab plotted day lengths over time and found a curved line. Arbab attributed this to the change of water volume present affecting Earth's rotation.
For most diurnal animals, the day naturally begins at dawn and ends at sunset. Humans, with their cultural norms and scientific knowledge, have employed several different conceptions of the day's boundaries.
In the Hebrew Bible, Genesis 1:5 defines a day in terms of "evening" and "morning" before recounting the creation of the Sun to illuminate it: "And God called the light Day, and the darkness he called Night. And the evening and the morning were the first day." The Jewish day begins at either sunset or nightfall (when three second-magnitude stars appear). Medieval Europe also followed this tradition, known as Florentine reckoning: In this system, a reference like "two hours into the day" meant two hours after sunset and thus times during the evening need to be shifted back one calendar day in modern reckoning. Days such as Christmas Eve, Halloween (“All Hallows’ Eve”), and the Eve of Saint Agnes are remnants of the older pattern when holidays began during the prior evening.
The common convention among the ancient Romans, ancient Chinese and in modern times is for the civil day to begin at midnight, i.e. 00:00, and to last a full 24 hours until 24:00, i.e. 00:00 of the next day.
In ancient Egypt the day was reckoned from sunrise to sunrise.
Prior to 1926, Turkey had two time systems: Turkish, counting the hours from sunset, and French, counting the hours from midnight.
Humans have divided the day in rough periods, which can have cultural implications, and other effects on humans' biological processes. The parts of the day do not have set times; they can vary by lifestyle or hours of daylight in a given place.
Daytime is the part of the day during which sunlight directly reaches the ground, assuming that there are no obstacles. The length of daytime averages slightly more than half of the 24-hour day. Two effects make daytime on average longer than night. The Sun is not a point but has an apparent size of about 32 minutes of arc. Additionally, the atmosphere refracts sunlight in such a way that some of it reaches the ground even when the Sun is below the horizon by about 34 minutes of arc. So the first light reaches the ground when the centre of the Sun is still below the horizon by about 50 minutes of arc. Thus, daytime is on average around 7 minutes longer than 12 hours.
Daytime is further divided into morning, afternoon, and evening. Morning occurs between sunrise and noon. Afternoon occurs between noon and sunset, or between noon and the start of evening. This period of time sees human's highest body temperature, an increase of traffic collisions, and a decrease of productivity. Evening begins around 5 or 6 pm, or when the sun sets, and ends when one goes to bed.
Twilight is the period before sunrise and after sunset in which there is natural light but no direct sunlight. The morning twilight begins at dawn and ends at sunrise, while the evening twilight begins at sunset and ends at dusk. Both periods of twilight can be divided into civil twilight, nautical twilight, and astronomical twilight. Civil twilight is when the sun is up to 6 degrees below the horizon; nautical when it is up to 12 degrees below, and astronomical when it is up to 18 degrees below.
Night is the period in which the sky is dark; the period between dusk and dawn where no light from the sun is visible. Light pollution during night can impact human and animal life, for example by disrupting sleep. | [
{
"paragraph_id": 0,
"text": "A day is the time period of a full rotation of the Earth with respect to the Sun. On average, this is 24 hours (86,400 seconds). As a day passes at a given location it experiences morning, noon, afternoon, evening, and night. This daily cycle drives circadian rhythms in many organisms, which are vital to many life processes.",
"title": ""
},
{
"paragraph_id": 1,
"text": "A collection of sequential days is organized into calendars as dates, almost always into weeks, months and years. A solar calendar organizes dates based on the Sun's annual cycle, giving consistent start dates for the four seasons from year to year. A lunar calendar organizes dates based on the Moon's lunar phase.",
"title": ""
},
{
"paragraph_id": 2,
"text": "In common usage, a day starts at midnight, written as 00:00 or 12:00 am in 24- or 12-hour clocks, respectively. Because the time of midnight varies between locations, time zones are set up to facilitate the use of a uniform standard time. Other conventions are sometimes used, for example the Jewish religious calendar counts days from sunset to sunset, so the Jewish Sabbath begins at sundown on Friday. In astronomy, a day begins at noon so that observations throughout a single night are recorded as happening on the same day.",
"title": ""
},
{
"paragraph_id": 3,
"text": "In specific applications, the definition of a day is slightly modified, such as in the SI day (exactly 86,400 seconds) used for computers and standards keeping, local mean time accounting of the Earth's natural fluctuation of a solar day, and stellar day and sidereal day (using the celestial sphere) used for astronomy. In most countries outside of the tropics, daylight saving time is practiced, and each year there will be one 23-hour civil day and one 25-hour civil day. Due to slight variations in the rotation of the Earth, there are rare times when a leap second will get inserted at the end of a UTC day, and so while almost all days have a duration of 86,400 seconds, there are these exceptional cases of a day with 86,401 seconds (in the half-century spanning 1972 through 2022, there have been a total of 27 leap seconds that have been inserted, so roughly once every other year).",
"title": ""
},
{
"paragraph_id": 4,
"text": "The term comes from the Old English term dæġ (/dæj/), with its cognates such as dagur in Icelandic, Tag in German, and dag in Norwegian, Danish, Swedish and Dutch – all stemming from a Proto-Germanic root *dagaz. As of October 17, 2015, day is the 205th most common word in US English, and the 210th most common in UK English.",
"title": "Etymology"
},
{
"paragraph_id": 5,
"text": "Several definitions of this universal human concept are used according to context, need, and convenience. Besides the day of 24 hours (86,400 seconds), the word day is used for several different spans of time based on the rotation of the Earth around its axis. An important one is the solar day, the time it takes for the Sun to return to its culmination point (its highest point in the sky). Due to an orbit's eccentricity, the Sun resides in one of the orbit's foci instead of the middle. Consequently, due to Kepler's second law, the planet travels at different speeds at various positions in its orbit, and thus a solar day is not the same length of time throughout the orbital year. Because the Earth moves along an eccentric orbit around the Sun while the Earth spins on an inclined axis, this period can be up to 7.9 seconds more than (or less than) 24 hours. In recent decades, the average length of a solar day on Earth has been about 86,400.002 seconds (24.000 000 6 hours). There are currently about 365.2421875 solar days in one mean tropical year.",
"title": "Definitions"
},
{
"paragraph_id": 6,
"text": "Ancient custom has a new day starting at either the rising or setting of the Sun on the local horizon (Italian reckoning, for example, being 24 hours from sunset, old style). The exact moment of, and the interval between, two sunrises or sunsets depends on the geographical position (longitude and latitude, as well as altitude), and the time of year (as indicated by ancient hemispherical sundials).",
"title": "Definitions"
},
{
"paragraph_id": 7,
"text": "A more constant day can be defined by the Sun passing through the local meridian, which happens at local noon (upper culmination) or midnight (lower culmination). The exact moment is dependent on the geographical longitude, and to a lesser extent on the time of the year. The length of such a day is nearly constant (24 hours ± 30 seconds). This is the time as indicated by modern sundials.",
"title": "Definitions"
},
{
"paragraph_id": 8,
"text": "A further improvement defines a fictitious mean Sun that moves with constant speed along the celestial equator; the speed is the same as the average speed of the real Sun, but this removes the variation over a year as the Earth moves along its orbit around the Sun (due to both its velocity and its axial tilt).",
"title": "Definitions"
},
{
"paragraph_id": 9,
"text": "In terms of Earth's rotation, the average day length is about 360.9856°. A day lasts for more than 360° of rotation because of the Earth's revolution around the Sun. With a full year being slightly more than 360 days, the Earth's daily orbit around the Sun is slightly less than 1°, so the day is slightly less than 361° of rotation.",
"title": "Definitions"
},
{
"paragraph_id": 10,
"text": "Elsewhere in the Solar System or other parts of the universe, a day is a full rotation of other large astronomical objects with respect to its star.",
"title": "Definitions"
},
{
"paragraph_id": 11,
"text": "For civil purposes, a common clock time is typically defined for an entire region based on the local mean solar time at a central meridian. Such time zones began to be adopted about the middle of the 19th century when railroads with regularly occurring schedules came into use, with most major countries having adopted them by 1929. As of 2015, throughout the world, 40 such zones are now in use: the central zone, from which all others are defined as offsets, is known as UTC±00, which uses Coordinated Universal Time (UTC).",
"title": "Definitions"
},
{
"paragraph_id": 12,
"text": "The most common convention starts the civil day at midnight: this is near the time of the lower culmination of the Sun on the central meridian of the time zone. Such a day may be called a calendar day.",
"title": "Definitions"
},
{
"paragraph_id": 13,
"text": "A day is commonly divided into 24 hours, with each hour being made up of 60 minutes, and each minute composed of 60 seconds.",
"title": "Definitions"
},
{
"paragraph_id": 14,
"text": "A sidereal day or stellar day is the span of time it takes for the Earth to make one entire rotation with respect to the celestial background or a distant star (assumed to be fixed). Measuring a day as such is used in astronomy. A sidereal day is about 4 minutes less than a solar day of 24 hours (23 hours 56 minutes and 4.09 seconds), or 0.99726968 of a solar day of 24 hours. There are about 366.2422 stellar days in one mean tropical year (one stellar day more than the number of solar days).",
"title": "Definitions"
},
{
"paragraph_id": 15,
"text": "Besides a stellar day on Earth, other bodies in the Solar System have day times, the durations of these being:",
"title": "Definitions"
},
{
"paragraph_id": 16,
"text": "In the International System of Units (SI), a day not an official unit, but is accepted for use with SI. A day, with symbol d, is defined using SI units as 86,400 seconds; the second is the base unit of time in SI units. In 1967–68, during the 13th CGPM (Resolution 1), the International Bureau of Weights and Measures (BIPM) redefined a second as \"... the duration of 9,192,631,770 periods of the radiation corresponding to the transition between two hyperfine levels of the ground state of the caesium 133 atom.\" This makes the SI-based day last exactly 794,243,384,928,000 of those periods.",
"title": "Definitions"
},
{
"paragraph_id": 17,
"text": "Various decimal or metric time proposals have been made, but do not redefine the day, and use the day or sidereal day as a base unit. Metric time uses metric prefixes to keep time. It uses the day as the base unit, and smaller units being fractions of a day: a metric hour (deci) is 1⁄10 of a day; a metric minute (milli) is 1⁄1000 of a day; etc. Similarly, in decimal time, the length of a day is static to normal time. A day is also split into 10 hours, and 10 days comprise a décade – the equivalent of a week. 3 décades make a month. Various decimal time proposals which do not redefine the day: Henri de Sarrauton's proposal kept days, and subdivided hours into 100 minutes; in Mendizábal y Tamborel's proposal, the sidereal day was the basic unit, with subdivisions made upon it; and Rey-Pailhade's proposal divided the day 100 cés.",
"title": "Definitions"
},
{
"paragraph_id": 18,
"text": "The word refers to various similarly defined ideas, such as:",
"title": "Definitions"
},
{
"paragraph_id": 19,
"text": "Mainly due to tidal deceleration – the Moon's gravitational pull slowing down the Earth's rotation – the Earth's rotational period is slowing. Because of the way the second is defined, the mean length of a solar day is now about 86,400.002 seconds, and is increasing by about 2 milliseconds per century.",
"title": "Variations in length"
},
{
"paragraph_id": 20,
"text": "Since the rotation rate of the Earth is slowing, the length of a SI second fell out of sync with a second derived from the rotational period. This arose the need for leap seconds, which insert extra seconds into Coordinated Universal Time (UTC). Although typically 86,400 SI seconds in duration, a civil day can be either 86,401 or 86,399 SI seconds long on such a day. Other than the two-millisecond variation from tidal deceleration, other factors minutely affect the day's length, which creates an irregularity in the placement of leap seconds. Leap seconds are announced in advance by the International Earth Rotation and Reference Systems Service (IERS), which measures the Earth's rotation and determines whether a leap second is necessary.",
"title": "Variations in length"
},
{
"paragraph_id": 21,
"text": "Discovered by paleontologist John W. Wells, the day lengths of geological periods have been estimated by measuring sedimentation rings in coral fossils, due to some biological systems being affected by the tide. The length of a day at the Earth's formation is estimated at 6 hours. Arbab I. Arbab plotted day lengths over time and found a curved line. Arbab attributed this to the change of water volume present affecting Earth's rotation.",
"title": "Variations in length"
},
{
"paragraph_id": 22,
"text": "For most diurnal animals, the day naturally begins at dawn and ends at sunset. Humans, with their cultural norms and scientific knowledge, have employed several different conceptions of the day's boundaries.",
"title": "Boundaries"
},
{
"paragraph_id": 23,
"text": "In the Hebrew Bible, Genesis 1:5 defines a day in terms of \"evening\" and \"morning\" before recounting the creation of the Sun to illuminate it: \"And God called the light Day, and the darkness he called Night. And the evening and the morning were the first day.\" The Jewish day begins at either sunset or nightfall (when three second-magnitude stars appear). Medieval Europe also followed this tradition, known as Florentine reckoning: In this system, a reference like \"two hours into the day\" meant two hours after sunset and thus times during the evening need to be shifted back one calendar day in modern reckoning. Days such as Christmas Eve, Halloween (“All Hallows’ Eve”), and the Eve of Saint Agnes are remnants of the older pattern when holidays began during the prior evening.",
"title": "Boundaries"
},
{
"paragraph_id": 24,
"text": "The common convention among the ancient Romans, ancient Chinese and in modern times is for the civil day to begin at midnight, i.e. 00:00, and to last a full 24 hours until 24:00, i.e. 00:00 of the next day.",
"title": "Boundaries"
},
{
"paragraph_id": 25,
"text": "In ancient Egypt the day was reckoned from sunrise to sunrise.",
"title": "Boundaries"
},
{
"paragraph_id": 26,
"text": "Prior to 1926, Turkey had two time systems: Turkish, counting the hours from sunset, and French, counting the hours from midnight.",
"title": "Boundaries"
},
{
"paragraph_id": 27,
"text": "Humans have divided the day in rough periods, which can have cultural implications, and other effects on humans' biological processes. The parts of the day do not have set times; they can vary by lifestyle or hours of daylight in a given place.",
"title": "Parts"
},
{
"paragraph_id": 28,
"text": "Daytime is the part of the day during which sunlight directly reaches the ground, assuming that there are no obstacles. The length of daytime averages slightly more than half of the 24-hour day. Two effects make daytime on average longer than night. The Sun is not a point but has an apparent size of about 32 minutes of arc. Additionally, the atmosphere refracts sunlight in such a way that some of it reaches the ground even when the Sun is below the horizon by about 34 minutes of arc. So the first light reaches the ground when the centre of the Sun is still below the horizon by about 50 minutes of arc. Thus, daytime is on average around 7 minutes longer than 12 hours.",
"title": "Parts"
},
{
"paragraph_id": 29,
"text": "Daytime is further divided into morning, afternoon, and evening. Morning occurs between sunrise and noon. Afternoon occurs between noon and sunset, or between noon and the start of evening. This period of time sees human's highest body temperature, an increase of traffic collisions, and a decrease of productivity. Evening begins around 5 or 6 pm, or when the sun sets, and ends when one goes to bed.",
"title": "Parts"
},
{
"paragraph_id": 30,
"text": "Twilight is the period before sunrise and after sunset in which there is natural light but no direct sunlight. The morning twilight begins at dawn and ends at sunrise, while the evening twilight begins at sunset and ends at dusk. Both periods of twilight can be divided into civil twilight, nautical twilight, and astronomical twilight. Civil twilight is when the sun is up to 6 degrees below the horizon; nautical when it is up to 12 degrees below, and astronomical when it is up to 18 degrees below.",
"title": "Parts"
},
{
"paragraph_id": 31,
"text": "Night is the period in which the sky is dark; the period between dusk and dawn where no light from the sun is visible. Light pollution during night can impact human and animal life, for example by disrupting sleep.",
"title": "Parts"
}
] | A day is the time period of a full rotation of the Earth with respect to the Sun. On average, this is 24 hours. As a day passes at a given location it experiences morning, noon, afternoon, evening, and night. This daily cycle drives circadian rhythms in many organisms, which are vital to many life processes. A collection of sequential days is organized into calendars as dates, almost always into weeks, months and years. A solar calendar organizes dates based on the Sun's annual cycle, giving consistent start dates for the four seasons from year to year. A lunar calendar organizes dates based on the Moon's lunar phase. In common usage, a day starts at midnight, written as 00:00 or 12:00 am in 24- or 12-hour clocks, respectively. Because the time of midnight varies between locations, time zones are set up to facilitate the use of a uniform standard time. Other conventions are sometimes used, for example the Jewish religious calendar counts days from sunset to sunset, so the Jewish Sabbath begins at sundown on Friday. In astronomy, a day begins at noon so that observations throughout a single night are recorded as happening on the same day. In specific applications, the definition of a day is slightly modified, such as in the SI day used for computers and standards keeping, local mean time accounting of the Earth's natural fluctuation of a solar day, and stellar day and sidereal day used for astronomy. In most countries outside of the tropics, daylight saving time is practiced, and each year there will be one 23-hour civil day and one 25-hour civil day. Due to slight variations in the rotation of the Earth, there are rare times when a leap second will get inserted at the end of a UTC day, and so while almost all days have a duration of 86,400 seconds, there are these exceptional cases of a day with 86,401 seconds. | 2001-11-06T00:05:19Z | 2023-12-21T22:39:47Z | [
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] | https://en.wikipedia.org/wiki/Day |
8,377 | Database | In computing, a database is an organized collection of data or a type of data store based on the use of a database management system (DBMS), the software that interacts with end users, applications, and the database itself to capture and analyze the data. The DBMS additionally encompasses the core facilities provided to administer the database. The sum total of the database, the DBMS and the associated applications can be referred to as a database system. Often the term "database" is also used loosely to refer to any of the DBMS, the database system or an application associated with the database.
Small databases can be stored on a file system, while large databases are hosted on computer clusters or cloud storage. The design of databases spans formal techniques and practical considerations, including data modeling, efficient data representation and storage, query languages, security and privacy of sensitive data, and distributed computing issues, including supporting concurrent access and fault tolerance.
Computer scientists may classify database management systems according to the database models that they support. Relational databases became dominant in the 1980s. These model data as rows and columns in a series of tables, and the vast majority use SQL for writing and querying data. In the 2000s, non-relational databases became popular, collectively referred to as NoSQL, because they use different query languages.
Formally, a "database" refers to a set of related data accessed through the use of a "database management system" (DBMS), which is an integrated set of computer software that allows users to interact with one or more databases and provides access to all of the data contained in the database (although restrictions may exist that limit access to particular data). The DBMS provides various functions that allow entry, storage and retrieval of large quantities of information and provides ways to manage how that information is organized.
Because of the close relationship between them, the term "database" is often used casually to refer to both a database and the DBMS used to manipulate it.
Outside the world of professional information technology, the term database is often used to refer to any collection of related data (such as a spreadsheet or a card index) as size and usage requirements typically necessitate use of a database management system.
Existing DBMSs provide various functions that allow management of a database and its data which can be classified into four main functional groups:
Both a database and its DBMS conform to the principles of a particular database model. "Database system" refers collectively to the database model, database management system, and database.
Physically, database servers are dedicated computers that hold the actual databases and run only the DBMS and related software. Database servers are usually multiprocessor computers, with generous memory and RAID disk arrays used for stable storage. Hardware database accelerators, connected to one or more servers via a high-speed channel, are also used in large-volume transaction processing environments. DBMSs are found at the heart of most database applications. DBMSs may be built around a custom multitasking kernel with built-in networking support, but modern DBMSs typically rely on a standard operating system to provide these functions.
Since DBMSs comprise a significant market, computer and storage vendors often take into account DBMS requirements in their own development plans.
Databases and DBMSs can be categorized according to the database model(s) that they support (such as relational or XML), the type(s) of computer they run on (from a server cluster to a mobile phone), the query language(s) used to access the database (such as SQL or XQuery), and their internal engineering, which affects performance, scalability, resilience, and security.
The sizes, capabilities, and performance of databases and their respective DBMSs have grown in orders of magnitude. These performance increases were enabled by the technology progress in the areas of processors, computer memory, computer storage, and computer networks. The concept of a database was made possible by the emergence of direct access storage media such as magnetic disks, which became widely available in the mid-1960s; earlier systems relied on sequential storage of data on magnetic tape. The subsequent development of database technology can be divided into three eras based on data model or structure: navigational, SQL/relational, and post-relational.
The two main early navigational data models were the hierarchical model and the CODASYL model (network model). These were characterized by the use of pointers (often physical disk addresses) to follow relationships from one record to another.
The relational model, first proposed in 1970 by Edgar F. Codd, departed from this tradition by insisting that applications should search for data by content, rather than by following links. The relational model employs sets of ledger-style tables, each used for a different type of entity. Only in the mid-1980s did computing hardware become powerful enough to allow the wide deployment of relational systems (DBMSs plus applications). By the early 1990s, however, relational systems dominated in all large-scale data processing applications, and as of 2018 they remain dominant: IBM Db2, Oracle, MySQL, and Microsoft SQL Server are the most searched DBMS. The dominant database language, standardized SQL for the relational model, has influenced database languages for other data models.
Object databases were developed in the 1980s to overcome the inconvenience of object–relational impedance mismatch, which led to the coining of the term "post-relational" and also the development of hybrid object–relational databases.
The next generation of post-relational databases in the late 2000s became known as NoSQL databases, introducing fast key–value stores and document-oriented databases. A competing "next generation" known as NewSQL databases attempted new implementations that retained the relational/SQL model while aiming to match the high performance of NoSQL compared to commercially available relational DBMSs.
The introduction of the term database coincided with the availability of direct-access storage (disks and drums) from the mid-1960s onwards. The term represented a contrast with the tape-based systems of the past, allowing shared interactive use rather than daily batch processing. The Oxford English Dictionary cites a 1962 report by the System Development Corporation of California as the first to use the term "data-base" in a specific technical sense.
As computers grew in speed and capability, a number of general-purpose database systems emerged; by the mid-1960s a number of such systems had come into commercial use. Interest in a standard began to grow, and Charles Bachman, author of one such product, the Integrated Data Store (IDS), founded the Database Task Group within CODASYL, the group responsible for the creation and standardization of COBOL. In 1971, the Database Task Group delivered their standard, which generally became known as the CODASYL approach, and soon a number of commercial products based on this approach entered the market.
The CODASYL approach offered applications the ability to navigate around a linked data set which was formed into a large network. Applications could find records by one of three methods:
Later systems added B-trees to provide alternate access paths. Many CODASYL databases also added a declarative query language for end users (as distinct from the navigational API). However, CODASYL databases were complex and required significant training and effort to produce useful applications.
IBM also had its own DBMS in 1966, known as Information Management System (IMS). IMS was a development of software written for the Apollo program on the System/360. IMS was generally similar in concept to CODASYL, but used a strict hierarchy for its model of data navigation instead of CODASYL's network model. Both concepts later became known as navigational databases due to the way data was accessed: the term was popularized by Bachman's 1973 Turing Award presentation The Programmer as Navigator. IMS is classified by IBM as a hierarchical database. IDMS and Cincom Systems' TOTAL databases are classified as network databases. IMS remains in use as of 2014.
Edgar F. Codd worked at IBM in San Jose, California, in one of their offshoot offices that were primarily involved in the development of hard disk systems. He was unhappy with the navigational model of the CODASYL approach, notably the lack of a "search" facility. In 1970, he wrote a number of papers that outlined a new approach to database construction that eventually culminated in the groundbreaking A Relational Model of Data for Large Shared Data Banks.
In this paper, he described a new system for storing and working with large databases. Instead of records being stored in some sort of linked list of free-form records as in CODASYL, Codd's idea was to organize the data as a number of "tables", each table being used for a different type of entity. Each table would contain a fixed number of columns containing the attributes of the entity. One or more columns of each table were designated as a primary key by which the rows of the table could be uniquely identified; cross-references between tables always used these primary keys, rather than disk addresses, and queries would join tables based on these key relationships, using a set of operations based on the mathematical system of relational calculus (from which the model takes its name). Splitting the data into a set of normalized tables (or relations) aimed to ensure that each "fact" was only stored once, thus simplifying update operations. Virtual tables called views could present the data in different ways for different users, but views could not be directly updated.
Codd used mathematical terms to define the model: relations, tuples, and domains rather than tables, rows, and columns. The terminology that is now familiar came from early implementations. Codd would later criticize the tendency for practical implementations to depart from the mathematical foundations on which the model was based.
The use of primary keys (user-oriented identifiers) to represent cross-table relationships, rather than disk addresses, had two primary motivations. From an engineering perspective, it enabled tables to be relocated and resized without expensive database reorganization. But Codd was more interested in the difference in semantics: the use of explicit identifiers made it easier to define update operations with clean mathematical definitions, and it also enabled query operations to be defined in terms of the established discipline of first-order predicate calculus; because these operations have clean mathematical properties, it becomes possible to rewrite queries in provably correct ways, which is the basis of query optimization. There is no loss of expressiveness compared with the hierarchic or network models, though the connections between tables are no longer so explicit.
In the hierarchic and network models, records were allowed to have a complex internal structure. For example, the salary history of an employee might be represented as a "repeating group" within the employee record. In the relational model, the process of normalization led to such internal structures being replaced by data held in multiple tables, connected only by logical keys.
For instance, a common use of a database system is to track information about users, their name, login information, various addresses and phone numbers. In the navigational approach, all of this data would be placed in a single variable-length record. In the relational approach, the data would be normalized into a user table, an address table and a phone number table (for instance). Records would be created in these optional tables only if the address or phone numbers were actually provided.
As well as identifying rows/records using logical identifiers rather than disk addresses, Codd changed the way in which applications assembled data from multiple records. Rather than requiring applications to gather data one record at a time by navigating the links, they would use a declarative query language that expressed what data was required, rather than the access path by which it should be found. Finding an efficient access path to the data became the responsibility of the database management system, rather than the application programmer. This process, called query optimization, depended on the fact that queries were expressed in terms of mathematical logic.
Codd's paper was picked up by two people at Berkeley, Eugene Wong and Michael Stonebraker. They started a project known as INGRES using funding that had already been allocated for a geographical database project and student programmers to produce code. Beginning in 1973, INGRES delivered its first test products which were generally ready for widespread use in 1979. INGRES was similar to System R in a number of ways, including the use of a "language" for data access, known as QUEL. Over time, INGRES moved to the emerging SQL standard.
IBM itself did one test implementation of the relational model, PRTV, and a production one, Business System 12, both now discontinued. Honeywell wrote MRDS for Multics, and now there are two new implementations: Alphora Dataphor and Rel. Most other DBMS implementations usually called relational are actually SQL DBMSs.
In 1970, the University of Michigan began development of the MICRO Information Management System based on D.L. Childs' Set-Theoretic Data model. MICRO was used to manage very large data sets by the US Department of Labor, the U.S. Environmental Protection Agency, and researchers from the University of Alberta, the University of Michigan, and Wayne State University. It ran on IBM mainframe computers using the Michigan Terminal System. The system remained in production until 1998.
In the 1970s and 1980s, attempts were made to build database systems with integrated hardware and software. The underlying philosophy was that such integration would provide higher performance at a lower cost. Examples were IBM System/38, the early offering of Teradata, and the Britton Lee, Inc. database machine.
Another approach to hardware support for database management was ICL's CAFS accelerator, a hardware disk controller with programmable search capabilities. In the long term, these efforts were generally unsuccessful because specialized database machines could not keep pace with the rapid development and progress of general-purpose computers. Thus most database systems nowadays are software systems running on general-purpose hardware, using general-purpose computer data storage. However, this idea is still pursued in certain applications by some companies like Netezza and Oracle (Exadata).
IBM started working on a prototype system loosely based on Codd's concepts as System R in the early 1970s. The first version was ready in 1974/5, and work then started on multi-table systems in which the data could be split so that all of the data for a record (some of which is optional) did not have to be stored in a single large "chunk". Subsequent multi-user versions were tested by customers in 1978 and 1979, by which time a standardized query language – SQL – had been added. Codd's ideas were establishing themselves as both workable and superior to CODASYL, pushing IBM to develop a true production version of System R, known as SQL/DS, and, later, Database 2 (IBM Db2).
Larry Ellison's Oracle Database (or more simply, Oracle) started from a different chain, based on IBM's papers on System R. Though Oracle V1 implementations were completed in 1978, it was not until Oracle Version 2 when Ellison beat IBM to market in 1979.
Stonebraker went on to apply the lessons from INGRES to develop a new database, Postgres, which is now known as PostgreSQL. PostgreSQL is often used for global mission-critical applications (the .org and .info domain name registries use it as their primary data store, as do many large companies and financial institutions).
In Sweden, Codd's paper was also read and Mimer SQL was developed in the mid-1970s at Uppsala University. In 1984, this project was consolidated into an independent enterprise.
Another data model, the entity–relationship model, emerged in 1976 and gained popularity for database design as it emphasized a more familiar description than the earlier relational model. Later on, entity–relationship constructs were retrofitted as a data modeling construct for the relational model, and the difference between the two has become irrelevant.
The 1980s ushered in the age of desktop computing. The new computers empowered their users with spreadsheets like Lotus 1-2-3 and database software like dBASE. The dBASE product was lightweight and easy for any computer user to understand out of the box. C. Wayne Ratliff, the creator of dBASE, stated: "dBASE was different from programs like BASIC, C, FORTRAN, and COBOL in that a lot of the dirty work had already been done. The data manipulation is done by dBASE instead of by the user, so the user can concentrate on what he is doing, rather than having to mess with the dirty details of opening, reading, and closing files, and managing space allocation." dBASE was one of the top selling software titles in the 1980s and early 1990s.
The 1990s, along with a rise in object-oriented programming, saw a growth in how data in various databases were handled. Programmers and designers began to treat the data in their databases as objects. That is to say that if a person's data were in a database, that person's attributes, such as their address, phone number, and age, were now considered to belong to that person instead of being extraneous data. This allows for relations between data to be related to objects and their attributes and not to individual fields. The term "object–relational impedance mismatch" described the inconvenience of translating between programmed objects and database tables. Object databases and object–relational databases attempt to solve this problem by providing an object-oriented language (sometimes as extensions to SQL) that programmers can use as alternative to purely relational SQL. On the programming side, libraries known as object–relational mappings (ORMs) attempt to solve the same problem.
XML databases are a type of structured document-oriented database that allows querying based on XML document attributes. XML databases are mostly used in applications where the data is conveniently viewed as a collection of documents, with a structure that can vary from the very flexible to the highly rigid: examples include scientific articles, patents, tax filings, and personnel records.
NoSQL databases are often very fast, do not require fixed table schemas, avoid join operations by storing denormalized data, and are designed to scale horizontally.
In recent years, there has been a strong demand for massively distributed databases with high partition tolerance, but according to the CAP theorem, it is impossible for a distributed system to simultaneously provide consistency, availability, and partition tolerance guarantees. A distributed system can satisfy any two of these guarantees at the same time, but not all three. For that reason, many NoSQL databases are using what is called eventual consistency to provide both availability and partition tolerance guarantees with a reduced level of data consistency.
NewSQL is a class of modern relational databases that aims to provide the same scalable performance of NoSQL systems for online transaction processing (read-write) workloads while still using SQL and maintaining the ACID guarantees of a traditional database system.
Databases are used to support internal operations of organizations and to underpin online interactions with customers and suppliers (see Enterprise software).
Databases are used to hold administrative information and more specialized data, such as engineering data or economic models. Examples include computerized library systems, flight reservation systems, computerized parts inventory systems, and many content management systems that store websites as collections of webpages in a database.
One way to classify databases involves the type of their contents, for example: bibliographic, document-text, statistical, or multimedia objects. Another way is by their application area, for example: accounting, music compositions, movies, banking, manufacturing, or insurance. A third way is by some technical aspect, such as the database structure or interface type. This section lists a few of the adjectives used to characterize different kinds of databases.
Connolly and Begg define database management system (DBMS) as a "software system that enables users to define, create, maintain and control access to the database". Examples of DBMS's include MySQL, MariaDB, PostgreSQL, Microsoft SQL Server, Oracle Database, and Microsoft Access.
The DBMS acronym is sometimes extended to indicate the underlying database model, with RDBMS for the relational, OODBMS for the object (oriented) and ORDBMS for the object–relational model. Other extensions can indicate some other characteristics, such as DDBMS for a distributed database management systems.
The functionality provided by a DBMS can vary enormously. The core functionality is the storage, retrieval and update of data. Codd proposed the following functions and services a fully-fledged general purpose DBMS should provide:
It is also generally to be expected the DBMS will provide a set of utilities for such purposes as may be necessary to administer the database effectively, including import, export, monitoring, defragmentation and analysis utilities. The core part of the DBMS interacting between the database and the application interface sometimes referred to as the database engine.
Often DBMSs will have configuration parameters that can be statically and dynamically tuned, for example the maximum amount of main memory on a server the database can use. The trend is to minimize the amount of manual configuration, and for cases such as embedded databases the need to target zero-administration is paramount.
The large major enterprise DBMSs have tended to increase in size and functionality and have involved up to thousands of human years of development effort throughout their lifetime.
Early multi-user DBMS typically only allowed for the application to reside on the same computer with access via terminals or terminal emulation software. The client–server architecture was a development where the application resided on a client desktop and the database on a server allowing the processing to be distributed. This evolved into a multitier architecture incorporating application servers and web servers with the end user interface via a web browser with the database only directly connected to the adjacent tier.
A general-purpose DBMS will provide public application programming interfaces (API) and optionally a processor for database languages such as SQL to allow applications to be written to interact with and manipulate the database. A special purpose DBMS may use a private API and be specifically customized and linked to a single application. For example, an email system performs many of the functions of a general-purpose DBMS such as message insertion, message deletion, attachment handling, blocklist lookup, associating messages an email address and so forth however these functions are limited to what is required to handle email.
External interaction with the database will be via an application program that interfaces with the DBMS. This can range from a database tool that allows users to execute SQL queries textually or graphically, to a website that happens to use a database to store and search information.
A programmer will code interactions to the database (sometimes referred to as a datasource) via an application program interface (API) or via a database language. The particular API or language chosen will need to be supported by DBMS, possibly indirectly via a preprocessor or a bridging API. Some API's aim to be database independent, ODBC being a commonly known example. Other common API's include JDBC and ADO.NET.
Database languages are special-purpose languages, which allow one or more of the following tasks, sometimes distinguished as sublanguages:
Database languages are specific to a particular data model. Notable examples include:
A database language may also incorporate features like:
Database storage is the container of the physical materialization of a database. It comprises the internal (physical) level in the database architecture. It also contains all the information needed (e.g., metadata, "data about the data", and internal data structures) to reconstruct the conceptual level and external level from the internal level when needed. Databases as digital objects contain three layers of information which must be stored: the data, the structure, and the semantics. Proper storage of all three layers is needed for future preservation and longevity of the database. Putting data into permanent storage is generally the responsibility of the database engine a.k.a. "storage engine". Though typically accessed by a DBMS through the underlying operating system (and often using the operating systems' file systems as intermediates for storage layout), storage properties and configuration settings are extremely important for the efficient operation of the DBMS, and thus are closely maintained by database administrators. A DBMS, while in operation, always has its database residing in several types of storage (e.g., memory and external storage). The database data and the additional needed information, possibly in very large amounts, are coded into bits. Data typically reside in the storage in structures that look completely different from the way the data look at the conceptual and external levels, but in ways that attempt to optimize (the best possible) these levels' reconstruction when needed by users and programs, as well as for computing additional types of needed information from the data (e.g., when querying the database).
Some DBMSs support specifying which character encoding was used to store data, so multiple encodings can be used in the same database.
Various low-level database storage structures are used by the storage engine to serialize the data model so it can be written to the medium of choice. Techniques such as indexing may be used to improve performance. Conventional storage is row-oriented, but there are also column-oriented and correlation databases.
Often storage redundancy is employed to increase performance. A common example is storing materialized views, which consist of frequently needed external views or query results. Storing such views saves the expensive computing them each time they are needed. The downsides of materialized views are the overhead incurred when updating them to keep them synchronized with their original updated database data, and the cost of storage redundancy.
Occasionally a database employs storage redundancy by database objects replication (with one or more copies) to increase data availability (both to improve performance of simultaneous multiple end-user accesses to the same database object, and to provide resiliency in a case of partial failure of a distributed database). Updates of a replicated object need to be synchronized across the object copies. In many cases, the entire database is replicated.
With data virtualization, the data used remains in its original locations and real-time access is established to allow analytics across multiple sources. This can aid in resolving some technical difficulties such as compatibility problems when combining data from various platforms, lowering the risk of error caused by faulty data, and guaranteeing that the newest data is used. Furthermore, avoiding the creation of a new database containing personal information can make it easier to comply with privacy regulations. However, with data virtualization, the connection to all necessary data sources must be operational as there is no local copy of the data, which is one of the main drawbacks of the approach.
Database security deals with all various aspects of protecting the database content, its owners, and its users. It ranges from protection from intentional unauthorized database uses to unintentional database accesses by unauthorized entities (e.g., a person or a computer program).
Database access control deals with controlling who (a person or a certain computer program) are allowed to access what information in the database. The information may comprise specific database objects (e.g., record types, specific records, data structures), certain computations over certain objects (e.g., query types, or specific queries), or using specific access paths to the former (e.g., using specific indexes or other data structures to access information). Database access controls are set by special authorized (by the database owner) personnel that uses dedicated protected security DBMS interfaces.
This may be managed directly on an individual basis, or by the assignment of individuals and privileges to groups, or (in the most elaborate models) through the assignment of individuals and groups to roles which are then granted entitlements. Data security prevents unauthorized users from viewing or updating the database. Using passwords, users are allowed access to the entire database or subsets of it called "subschemas". For example, an employee database can contain all the data about an individual employee, but one group of users may be authorized to view only payroll data, while others are allowed access to only work history and medical data. If the DBMS provides a way to interactively enter and update the database, as well as interrogate it, this capability allows for managing personal databases.
Data security in general deals with protecting specific chunks of data, both physically (i.e., from corruption, or destruction, or removal; e.g., see physical security), or the interpretation of them, or parts of them to meaningful information (e.g., by looking at the strings of bits that they comprise, concluding specific valid credit-card numbers; e.g., see data encryption).
Change and access logging records who accessed which attributes, what was changed, and when it was changed. Logging services allow for a forensic database audit later by keeping a record of access occurrences and changes. Sometimes application-level code is used to record changes rather than leaving this in the database. Monitoring can be set up to attempt to detect security breaches. Therefore, organizations must take database security seriously because of the many benefits it provides. Organizations will be safeguarded from security breaches and hacking activities like firewall intrusion, virus spread, and ransom ware. This helps in protecting the company's essential information, which cannot be shared with outsiders at any cause.
Database transactions can be used to introduce some level of fault tolerance and data integrity after recovery from a crash. A database transaction is a unit of work, typically encapsulating a number of operations over a database (e.g., reading a database object, writing, acquiring or releasing a lock, etc.), an abstraction supported in database and also other systems. Each transaction has well defined boundaries in terms of which program/code executions are included in that transaction (determined by the transaction's programmer via special transaction commands).
The acronym ACID describes some ideal properties of a database transaction: atomicity, consistency, isolation, and durability.
A database built with one DBMS is not portable to another DBMS (i.e., the other DBMS cannot run it). However, in some situations, it is desirable to migrate a database from one DBMS to another. The reasons are primarily economical (different DBMSs may have different total costs of ownership or TCOs), functional, and operational (different DBMSs may have different capabilities). The migration involves the database's transformation from one DBMS type to another. The transformation should maintain (if possible) the database related application (i.e., all related application programs) intact. Thus, the database's conceptual and external architectural levels should be maintained in the transformation. It may be desired that also some aspects of the architecture internal level are maintained. A complex or large database migration may be a complicated and costly (one-time) project by itself, which should be factored into the decision to migrate. This is in spite of the fact that tools may exist to help migration between specific DBMSs. Typically, a DBMS vendor provides tools to help import databases from other popular DBMSs.
After designing a database for an application, the next stage is building the database. Typically, an appropriate general-purpose DBMS can be selected to be used for this purpose. A DBMS provides the needed user interfaces to be used by database administrators to define the needed application's data structures within the DBMS's respective data model. Other user interfaces are used to select needed DBMS parameters (like security related, storage allocation parameters, etc.).
When the database is ready (all its data structures and other needed components are defined), it is typically populated with initial application's data (database initialization, which is typically a distinct project; in many cases using specialized DBMS interfaces that support bulk insertion) before making it operational. In some cases, the database becomes operational while empty of application data, and data are accumulated during its operation.
After the database is created, initialized and populated it needs to be maintained. Various database parameters may need changing and the database may need to be tuned (tuning) for better performance; application's data structures may be changed or added, new related application programs may be written to add to the application's functionality, etc.
Sometimes it is desired to bring a database back to a previous state (for many reasons, e.g., cases when the database is found corrupted due to a software error, or if it has been updated with erroneous data). To achieve this, a backup operation is done occasionally or continuously, where each desired database state (i.e., the values of its data and their embedding in database's data structures) is kept within dedicated backup files (many techniques exist to do this effectively). When it is decided by a database administrator to bring the database back to this state (e.g., by specifying this state by a desired point in time when the database was in this state), these files are used to restore that state.
Static analysis techniques for software verification can be applied also in the scenario of query languages. In particular, the *Abstract interpretation framework has been extended to the field of query languages for relational databases as a way to support sound approximation techniques. The semantics of query languages can be tuned according to suitable abstractions of the concrete domain of data. The abstraction of relational database systems has many interesting applications, in particular, for security purposes, such as fine-grained access control, watermarking, etc.
Other DBMS features might include:
Increasingly, there are calls for a single system that incorporates all of these core functionalities into the same build, test, and deployment framework for database management and source control. Borrowing from other developments in the software industry, some market such offerings as "DevOps for database".
The first task of a database designer is to produce a conceptual data model that reflects the structure of the information to be held in the database. A common approach to this is to develop an entity–relationship model, often with the aid of drawing tools. Another popular approach is the Unified Modeling Language. A successful data model will accurately reflect the possible state of the external world being modeled: for example, if people can have more than one phone number, it will allow this information to be captured. Designing a good conceptual data model requires a good understanding of the application domain; it typically involves asking deep questions about the things of interest to an organization, like "can a customer also be a supplier?", or "if a product is sold with two different forms of packaging, are those the same product or different products?", or "if a plane flies from New York to Dubai via Frankfurt, is that one flight or two (or maybe even three)?". The answers to these questions establish definitions of the terminology used for entities (customers, products, flights, flight segments) and their relationships and attributes.
Producing the conceptual data model sometimes involves input from business processes, or the analysis of workflow in the organization. This can help to establish what information is needed in the database, and what can be left out. For example, it can help when deciding whether the database needs to hold historic data as well as current data.
Having produced a conceptual data model that users are happy with, the next stage is to translate this into a schema that implements the relevant data structures within the database. This process is often called logical database design, and the output is a logical data model expressed in the form of a schema. Whereas the conceptual data model is (in theory at least) independent of the choice of database technology, the logical data model will be expressed in terms of a particular database model supported by the chosen DBMS. (The terms data model and database model are often used interchangeably, but in this article we use data model for the design of a specific database, and database model for the modeling notation used to express that design).
The most popular database model for general-purpose databases is the relational model, or more precisely, the relational model as represented by the SQL language. The process of creating a logical database design using this model uses a methodical approach known as normalization. The goal of normalization is to ensure that each elementary "fact" is only recorded in one place, so that insertions, updates, and deletions automatically maintain consistency.
The final stage of database design is to make the decisions that affect performance, scalability, recovery, security, and the like, which depend on the particular DBMS. This is often called physical database design, and the output is the physical data model. A key goal during this stage is data independence, meaning that the decisions made for performance optimization purposes should be invisible to end-users and applications. There are two types of data independence: Physical data independence and logical data independence. Physical design is driven mainly by performance requirements, and requires a good knowledge of the expected workload and access patterns, and a deep understanding of the features offered by the chosen DBMS.
Another aspect of physical database design is security. It involves both defining access control to database objects as well as defining security levels and methods for the data itself.
A database model is a type of data model that determines the logical structure of a database and fundamentally determines in which manner data can be stored, organized, and manipulated. The most popular example of a database model is the relational model (or the SQL approximation of relational), which uses a table-based format.
Common logical data models for databases include:
An object–relational database combines the two related structures.
Physical data models include:
Other models include:
Specialized models are optimized for particular types of data:
A database management system provides three views of the database data:
While there is typically only one conceptual and internal view of the data, there can be any number of different external views. This allows users to see database information in a more business-related way rather than from a technical, processing viewpoint. For example, a financial department of a company needs the payment details of all employees as part of the company's expenses, but does not need details about employees that are in the interest of the human resources department. Thus different departments need different views of the company's database.
The three-level database architecture relates to the concept of data independence which was one of the major initial driving forces of the relational model. The idea is that changes made at a certain level do not affect the view at a higher level. For example, changes in the internal level do not affect application programs written using conceptual level interfaces, which reduces the impact of making physical changes to improve performance.
The conceptual view provides a level of indirection between internal and external. On the one hand it provides a common view of the database, independent of different external view structures, and on the other hand it abstracts away details of how the data are stored or managed (internal level). In principle every level, and even every external view, can be presented by a different data model. In practice usually a given DBMS uses the same data model for both the external and the conceptual levels (e.g., relational model). The internal level, which is hidden inside the DBMS and depends on its implementation, requires a different level of detail and uses its own types of data structure types.
Database technology has been an active research topic since the 1960s, both in academia and in the research and development groups of companies (for example IBM Research). Research activity includes theory and development of prototypes. Notable research topics have included models, the atomic transaction concept, related concurrency control techniques, query languages and query optimization methods, RAID, and more.
The database research area has several dedicated academic journals (for example, ACM Transactions on Database Systems-TODS, Data and Knowledge Engineering-DKE) and annual conferences (e.g., ACM SIGMOD, ACM PODS, VLDB, IEEE ICDE). | [
{
"paragraph_id": 0,
"text": "In computing, a database is an organized collection of data or a type of data store based on the use of a database management system (DBMS), the software that interacts with end users, applications, and the database itself to capture and analyze the data. The DBMS additionally encompasses the core facilities provided to administer the database. The sum total of the database, the DBMS and the associated applications can be referred to as a database system. Often the term \"database\" is also used loosely to refer to any of the DBMS, the database system or an application associated with the database.",
"title": ""
},
{
"paragraph_id": 1,
"text": "Small databases can be stored on a file system, while large databases are hosted on computer clusters or cloud storage. The design of databases spans formal techniques and practical considerations, including data modeling, efficient data representation and storage, query languages, security and privacy of sensitive data, and distributed computing issues, including supporting concurrent access and fault tolerance.",
"title": ""
},
{
"paragraph_id": 2,
"text": "Computer scientists may classify database management systems according to the database models that they support. Relational databases became dominant in the 1980s. These model data as rows and columns in a series of tables, and the vast majority use SQL for writing and querying data. In the 2000s, non-relational databases became popular, collectively referred to as NoSQL, because they use different query languages.",
"title": ""
},
{
"paragraph_id": 3,
"text": "Formally, a \"database\" refers to a set of related data accessed through the use of a \"database management system\" (DBMS), which is an integrated set of computer software that allows users to interact with one or more databases and provides access to all of the data contained in the database (although restrictions may exist that limit access to particular data). The DBMS provides various functions that allow entry, storage and retrieval of large quantities of information and provides ways to manage how that information is organized.",
"title": "Terminology and overview"
},
{
"paragraph_id": 4,
"text": "Because of the close relationship between them, the term \"database\" is often used casually to refer to both a database and the DBMS used to manipulate it.",
"title": "Terminology and overview"
},
{
"paragraph_id": 5,
"text": "Outside the world of professional information technology, the term database is often used to refer to any collection of related data (such as a spreadsheet or a card index) as size and usage requirements typically necessitate use of a database management system.",
"title": "Terminology and overview"
},
{
"paragraph_id": 6,
"text": "Existing DBMSs provide various functions that allow management of a database and its data which can be classified into four main functional groups:",
"title": "Terminology and overview"
},
{
"paragraph_id": 7,
"text": "Both a database and its DBMS conform to the principles of a particular database model. \"Database system\" refers collectively to the database model, database management system, and database.",
"title": "Terminology and overview"
},
{
"paragraph_id": 8,
"text": "Physically, database servers are dedicated computers that hold the actual databases and run only the DBMS and related software. Database servers are usually multiprocessor computers, with generous memory and RAID disk arrays used for stable storage. Hardware database accelerators, connected to one or more servers via a high-speed channel, are also used in large-volume transaction processing environments. DBMSs are found at the heart of most database applications. DBMSs may be built around a custom multitasking kernel with built-in networking support, but modern DBMSs typically rely on a standard operating system to provide these functions.",
"title": "Terminology and overview"
},
{
"paragraph_id": 9,
"text": "Since DBMSs comprise a significant market, computer and storage vendors often take into account DBMS requirements in their own development plans.",
"title": "Terminology and overview"
},
{
"paragraph_id": 10,
"text": "Databases and DBMSs can be categorized according to the database model(s) that they support (such as relational or XML), the type(s) of computer they run on (from a server cluster to a mobile phone), the query language(s) used to access the database (such as SQL or XQuery), and their internal engineering, which affects performance, scalability, resilience, and security.",
"title": "Terminology and overview"
},
{
"paragraph_id": 11,
"text": "The sizes, capabilities, and performance of databases and their respective DBMSs have grown in orders of magnitude. These performance increases were enabled by the technology progress in the areas of processors, computer memory, computer storage, and computer networks. The concept of a database was made possible by the emergence of direct access storage media such as magnetic disks, which became widely available in the mid-1960s; earlier systems relied on sequential storage of data on magnetic tape. The subsequent development of database technology can be divided into three eras based on data model or structure: navigational, SQL/relational, and post-relational.",
"title": "History"
},
{
"paragraph_id": 12,
"text": "The two main early navigational data models were the hierarchical model and the CODASYL model (network model). These were characterized by the use of pointers (often physical disk addresses) to follow relationships from one record to another.",
"title": "History"
},
{
"paragraph_id": 13,
"text": "The relational model, first proposed in 1970 by Edgar F. Codd, departed from this tradition by insisting that applications should search for data by content, rather than by following links. The relational model employs sets of ledger-style tables, each used for a different type of entity. Only in the mid-1980s did computing hardware become powerful enough to allow the wide deployment of relational systems (DBMSs plus applications). By the early 1990s, however, relational systems dominated in all large-scale data processing applications, and as of 2018 they remain dominant: IBM Db2, Oracle, MySQL, and Microsoft SQL Server are the most searched DBMS. The dominant database language, standardized SQL for the relational model, has influenced database languages for other data models.",
"title": "History"
},
{
"paragraph_id": 14,
"text": "Object databases were developed in the 1980s to overcome the inconvenience of object–relational impedance mismatch, which led to the coining of the term \"post-relational\" and also the development of hybrid object–relational databases.",
"title": "History"
},
{
"paragraph_id": 15,
"text": "The next generation of post-relational databases in the late 2000s became known as NoSQL databases, introducing fast key–value stores and document-oriented databases. A competing \"next generation\" known as NewSQL databases attempted new implementations that retained the relational/SQL model while aiming to match the high performance of NoSQL compared to commercially available relational DBMSs.",
"title": "History"
},
{
"paragraph_id": 16,
"text": "The introduction of the term database coincided with the availability of direct-access storage (disks and drums) from the mid-1960s onwards. The term represented a contrast with the tape-based systems of the past, allowing shared interactive use rather than daily batch processing. The Oxford English Dictionary cites a 1962 report by the System Development Corporation of California as the first to use the term \"data-base\" in a specific technical sense.",
"title": "History"
},
{
"paragraph_id": 17,
"text": "As computers grew in speed and capability, a number of general-purpose database systems emerged; by the mid-1960s a number of such systems had come into commercial use. Interest in a standard began to grow, and Charles Bachman, author of one such product, the Integrated Data Store (IDS), founded the Database Task Group within CODASYL, the group responsible for the creation and standardization of COBOL. In 1971, the Database Task Group delivered their standard, which generally became known as the CODASYL approach, and soon a number of commercial products based on this approach entered the market.",
"title": "History"
},
{
"paragraph_id": 18,
"text": "The CODASYL approach offered applications the ability to navigate around a linked data set which was formed into a large network. Applications could find records by one of three methods:",
"title": "History"
},
{
"paragraph_id": 19,
"text": "Later systems added B-trees to provide alternate access paths. Many CODASYL databases also added a declarative query language for end users (as distinct from the navigational API). However, CODASYL databases were complex and required significant training and effort to produce useful applications.",
"title": "History"
},
{
"paragraph_id": 20,
"text": "IBM also had its own DBMS in 1966, known as Information Management System (IMS). IMS was a development of software written for the Apollo program on the System/360. IMS was generally similar in concept to CODASYL, but used a strict hierarchy for its model of data navigation instead of CODASYL's network model. Both concepts later became known as navigational databases due to the way data was accessed: the term was popularized by Bachman's 1973 Turing Award presentation The Programmer as Navigator. IMS is classified by IBM as a hierarchical database. IDMS and Cincom Systems' TOTAL databases are classified as network databases. IMS remains in use as of 2014.",
"title": "History"
},
{
"paragraph_id": 21,
"text": "Edgar F. Codd worked at IBM in San Jose, California, in one of their offshoot offices that were primarily involved in the development of hard disk systems. He was unhappy with the navigational model of the CODASYL approach, notably the lack of a \"search\" facility. In 1970, he wrote a number of papers that outlined a new approach to database construction that eventually culminated in the groundbreaking A Relational Model of Data for Large Shared Data Banks.",
"title": "History"
},
{
"paragraph_id": 22,
"text": "In this paper, he described a new system for storing and working with large databases. Instead of records being stored in some sort of linked list of free-form records as in CODASYL, Codd's idea was to organize the data as a number of \"tables\", each table being used for a different type of entity. Each table would contain a fixed number of columns containing the attributes of the entity. One or more columns of each table were designated as a primary key by which the rows of the table could be uniquely identified; cross-references between tables always used these primary keys, rather than disk addresses, and queries would join tables based on these key relationships, using a set of operations based on the mathematical system of relational calculus (from which the model takes its name). Splitting the data into a set of normalized tables (or relations) aimed to ensure that each \"fact\" was only stored once, thus simplifying update operations. Virtual tables called views could present the data in different ways for different users, but views could not be directly updated.",
"title": "History"
},
{
"paragraph_id": 23,
"text": "Codd used mathematical terms to define the model: relations, tuples, and domains rather than tables, rows, and columns. The terminology that is now familiar came from early implementations. Codd would later criticize the tendency for practical implementations to depart from the mathematical foundations on which the model was based.",
"title": "History"
},
{
"paragraph_id": 24,
"text": "The use of primary keys (user-oriented identifiers) to represent cross-table relationships, rather than disk addresses, had two primary motivations. From an engineering perspective, it enabled tables to be relocated and resized without expensive database reorganization. But Codd was more interested in the difference in semantics: the use of explicit identifiers made it easier to define update operations with clean mathematical definitions, and it also enabled query operations to be defined in terms of the established discipline of first-order predicate calculus; because these operations have clean mathematical properties, it becomes possible to rewrite queries in provably correct ways, which is the basis of query optimization. There is no loss of expressiveness compared with the hierarchic or network models, though the connections between tables are no longer so explicit.",
"title": "History"
},
{
"paragraph_id": 25,
"text": "In the hierarchic and network models, records were allowed to have a complex internal structure. For example, the salary history of an employee might be represented as a \"repeating group\" within the employee record. In the relational model, the process of normalization led to such internal structures being replaced by data held in multiple tables, connected only by logical keys.",
"title": "History"
},
{
"paragraph_id": 26,
"text": "For instance, a common use of a database system is to track information about users, their name, login information, various addresses and phone numbers. In the navigational approach, all of this data would be placed in a single variable-length record. In the relational approach, the data would be normalized into a user table, an address table and a phone number table (for instance). Records would be created in these optional tables only if the address or phone numbers were actually provided.",
"title": "History"
},
{
"paragraph_id": 27,
"text": "As well as identifying rows/records using logical identifiers rather than disk addresses, Codd changed the way in which applications assembled data from multiple records. Rather than requiring applications to gather data one record at a time by navigating the links, they would use a declarative query language that expressed what data was required, rather than the access path by which it should be found. Finding an efficient access path to the data became the responsibility of the database management system, rather than the application programmer. This process, called query optimization, depended on the fact that queries were expressed in terms of mathematical logic.",
"title": "History"
},
{
"paragraph_id": 28,
"text": "Codd's paper was picked up by two people at Berkeley, Eugene Wong and Michael Stonebraker. They started a project known as INGRES using funding that had already been allocated for a geographical database project and student programmers to produce code. Beginning in 1973, INGRES delivered its first test products which were generally ready for widespread use in 1979. INGRES was similar to System R in a number of ways, including the use of a \"language\" for data access, known as QUEL. Over time, INGRES moved to the emerging SQL standard.",
"title": "History"
},
{
"paragraph_id": 29,
"text": "IBM itself did one test implementation of the relational model, PRTV, and a production one, Business System 12, both now discontinued. Honeywell wrote MRDS for Multics, and now there are two new implementations: Alphora Dataphor and Rel. Most other DBMS implementations usually called relational are actually SQL DBMSs.",
"title": "History"
},
{
"paragraph_id": 30,
"text": "In 1970, the University of Michigan began development of the MICRO Information Management System based on D.L. Childs' Set-Theoretic Data model. MICRO was used to manage very large data sets by the US Department of Labor, the U.S. Environmental Protection Agency, and researchers from the University of Alberta, the University of Michigan, and Wayne State University. It ran on IBM mainframe computers using the Michigan Terminal System. The system remained in production until 1998.",
"title": "History"
},
{
"paragraph_id": 31,
"text": "In the 1970s and 1980s, attempts were made to build database systems with integrated hardware and software. The underlying philosophy was that such integration would provide higher performance at a lower cost. Examples were IBM System/38, the early offering of Teradata, and the Britton Lee, Inc. database machine.",
"title": "History"
},
{
"paragraph_id": 32,
"text": "Another approach to hardware support for database management was ICL's CAFS accelerator, a hardware disk controller with programmable search capabilities. In the long term, these efforts were generally unsuccessful because specialized database machines could not keep pace with the rapid development and progress of general-purpose computers. Thus most database systems nowadays are software systems running on general-purpose hardware, using general-purpose computer data storage. However, this idea is still pursued in certain applications by some companies like Netezza and Oracle (Exadata).",
"title": "History"
},
{
"paragraph_id": 33,
"text": "IBM started working on a prototype system loosely based on Codd's concepts as System R in the early 1970s. The first version was ready in 1974/5, and work then started on multi-table systems in which the data could be split so that all of the data for a record (some of which is optional) did not have to be stored in a single large \"chunk\". Subsequent multi-user versions were tested by customers in 1978 and 1979, by which time a standardized query language – SQL – had been added. Codd's ideas were establishing themselves as both workable and superior to CODASYL, pushing IBM to develop a true production version of System R, known as SQL/DS, and, later, Database 2 (IBM Db2).",
"title": "History"
},
{
"paragraph_id": 34,
"text": "Larry Ellison's Oracle Database (or more simply, Oracle) started from a different chain, based on IBM's papers on System R. Though Oracle V1 implementations were completed in 1978, it was not until Oracle Version 2 when Ellison beat IBM to market in 1979.",
"title": "History"
},
{
"paragraph_id": 35,
"text": "Stonebraker went on to apply the lessons from INGRES to develop a new database, Postgres, which is now known as PostgreSQL. PostgreSQL is often used for global mission-critical applications (the .org and .info domain name registries use it as their primary data store, as do many large companies and financial institutions).",
"title": "History"
},
{
"paragraph_id": 36,
"text": "In Sweden, Codd's paper was also read and Mimer SQL was developed in the mid-1970s at Uppsala University. In 1984, this project was consolidated into an independent enterprise.",
"title": "History"
},
{
"paragraph_id": 37,
"text": "Another data model, the entity–relationship model, emerged in 1976 and gained popularity for database design as it emphasized a more familiar description than the earlier relational model. Later on, entity–relationship constructs were retrofitted as a data modeling construct for the relational model, and the difference between the two has become irrelevant.",
"title": "History"
},
{
"paragraph_id": 38,
"text": "The 1980s ushered in the age of desktop computing. The new computers empowered their users with spreadsheets like Lotus 1-2-3 and database software like dBASE. The dBASE product was lightweight and easy for any computer user to understand out of the box. C. Wayne Ratliff, the creator of dBASE, stated: \"dBASE was different from programs like BASIC, C, FORTRAN, and COBOL in that a lot of the dirty work had already been done. The data manipulation is done by dBASE instead of by the user, so the user can concentrate on what he is doing, rather than having to mess with the dirty details of opening, reading, and closing files, and managing space allocation.\" dBASE was one of the top selling software titles in the 1980s and early 1990s.",
"title": "History"
},
{
"paragraph_id": 39,
"text": "The 1990s, along with a rise in object-oriented programming, saw a growth in how data in various databases were handled. Programmers and designers began to treat the data in their databases as objects. That is to say that if a person's data were in a database, that person's attributes, such as their address, phone number, and age, were now considered to belong to that person instead of being extraneous data. This allows for relations between data to be related to objects and their attributes and not to individual fields. The term \"object–relational impedance mismatch\" described the inconvenience of translating between programmed objects and database tables. Object databases and object–relational databases attempt to solve this problem by providing an object-oriented language (sometimes as extensions to SQL) that programmers can use as alternative to purely relational SQL. On the programming side, libraries known as object–relational mappings (ORMs) attempt to solve the same problem.",
"title": "History"
},
{
"paragraph_id": 40,
"text": "XML databases are a type of structured document-oriented database that allows querying based on XML document attributes. XML databases are mostly used in applications where the data is conveniently viewed as a collection of documents, with a structure that can vary from the very flexible to the highly rigid: examples include scientific articles, patents, tax filings, and personnel records.",
"title": "History"
},
{
"paragraph_id": 41,
"text": "NoSQL databases are often very fast, do not require fixed table schemas, avoid join operations by storing denormalized data, and are designed to scale horizontally.",
"title": "History"
},
{
"paragraph_id": 42,
"text": "In recent years, there has been a strong demand for massively distributed databases with high partition tolerance, but according to the CAP theorem, it is impossible for a distributed system to simultaneously provide consistency, availability, and partition tolerance guarantees. A distributed system can satisfy any two of these guarantees at the same time, but not all three. For that reason, many NoSQL databases are using what is called eventual consistency to provide both availability and partition tolerance guarantees with a reduced level of data consistency.",
"title": "History"
},
{
"paragraph_id": 43,
"text": "NewSQL is a class of modern relational databases that aims to provide the same scalable performance of NoSQL systems for online transaction processing (read-write) workloads while still using SQL and maintaining the ACID guarantees of a traditional database system.",
"title": "History"
},
{
"paragraph_id": 44,
"text": "Databases are used to support internal operations of organizations and to underpin online interactions with customers and suppliers (see Enterprise software).",
"title": "Use cases"
},
{
"paragraph_id": 45,
"text": "Databases are used to hold administrative information and more specialized data, such as engineering data or economic models. Examples include computerized library systems, flight reservation systems, computerized parts inventory systems, and many content management systems that store websites as collections of webpages in a database.",
"title": "Use cases"
},
{
"paragraph_id": 46,
"text": "One way to classify databases involves the type of their contents, for example: bibliographic, document-text, statistical, or multimedia objects. Another way is by their application area, for example: accounting, music compositions, movies, banking, manufacturing, or insurance. A third way is by some technical aspect, such as the database structure or interface type. This section lists a few of the adjectives used to characterize different kinds of databases.",
"title": "Classification"
},
{
"paragraph_id": 47,
"text": "Connolly and Begg define database management system (DBMS) as a \"software system that enables users to define, create, maintain and control access to the database\". Examples of DBMS's include MySQL, MariaDB, PostgreSQL, Microsoft SQL Server, Oracle Database, and Microsoft Access.",
"title": "Database management system"
},
{
"paragraph_id": 48,
"text": "The DBMS acronym is sometimes extended to indicate the underlying database model, with RDBMS for the relational, OODBMS for the object (oriented) and ORDBMS for the object–relational model. Other extensions can indicate some other characteristics, such as DDBMS for a distributed database management systems.",
"title": "Database management system"
},
{
"paragraph_id": 49,
"text": "The functionality provided by a DBMS can vary enormously. The core functionality is the storage, retrieval and update of data. Codd proposed the following functions and services a fully-fledged general purpose DBMS should provide:",
"title": "Database management system"
},
{
"paragraph_id": 50,
"text": "It is also generally to be expected the DBMS will provide a set of utilities for such purposes as may be necessary to administer the database effectively, including import, export, monitoring, defragmentation and analysis utilities. The core part of the DBMS interacting between the database and the application interface sometimes referred to as the database engine.",
"title": "Database management system"
},
{
"paragraph_id": 51,
"text": "Often DBMSs will have configuration parameters that can be statically and dynamically tuned, for example the maximum amount of main memory on a server the database can use. The trend is to minimize the amount of manual configuration, and for cases such as embedded databases the need to target zero-administration is paramount.",
"title": "Database management system"
},
{
"paragraph_id": 52,
"text": "The large major enterprise DBMSs have tended to increase in size and functionality and have involved up to thousands of human years of development effort throughout their lifetime.",
"title": "Database management system"
},
{
"paragraph_id": 53,
"text": "Early multi-user DBMS typically only allowed for the application to reside on the same computer with access via terminals or terminal emulation software. The client–server architecture was a development where the application resided on a client desktop and the database on a server allowing the processing to be distributed. This evolved into a multitier architecture incorporating application servers and web servers with the end user interface via a web browser with the database only directly connected to the adjacent tier.",
"title": "Database management system"
},
{
"paragraph_id": 54,
"text": "A general-purpose DBMS will provide public application programming interfaces (API) and optionally a processor for database languages such as SQL to allow applications to be written to interact with and manipulate the database. A special purpose DBMS may use a private API and be specifically customized and linked to a single application. For example, an email system performs many of the functions of a general-purpose DBMS such as message insertion, message deletion, attachment handling, blocklist lookup, associating messages an email address and so forth however these functions are limited to what is required to handle email.",
"title": "Database management system"
},
{
"paragraph_id": 55,
"text": "External interaction with the database will be via an application program that interfaces with the DBMS. This can range from a database tool that allows users to execute SQL queries textually or graphically, to a website that happens to use a database to store and search information.",
"title": "Application"
},
{
"paragraph_id": 56,
"text": "A programmer will code interactions to the database (sometimes referred to as a datasource) via an application program interface (API) or via a database language. The particular API or language chosen will need to be supported by DBMS, possibly indirectly via a preprocessor or a bridging API. Some API's aim to be database independent, ODBC being a commonly known example. Other common API's include JDBC and ADO.NET.",
"title": "Application"
},
{
"paragraph_id": 57,
"text": "Database languages are special-purpose languages, which allow one or more of the following tasks, sometimes distinguished as sublanguages:",
"title": "Database languages"
},
{
"paragraph_id": 58,
"text": "Database languages are specific to a particular data model. Notable examples include:",
"title": "Database languages"
},
{
"paragraph_id": 59,
"text": "A database language may also incorporate features like:",
"title": "Database languages"
},
{
"paragraph_id": 60,
"text": "Database storage is the container of the physical materialization of a database. It comprises the internal (physical) level in the database architecture. It also contains all the information needed (e.g., metadata, \"data about the data\", and internal data structures) to reconstruct the conceptual level and external level from the internal level when needed. Databases as digital objects contain three layers of information which must be stored: the data, the structure, and the semantics. Proper storage of all three layers is needed for future preservation and longevity of the database. Putting data into permanent storage is generally the responsibility of the database engine a.k.a. \"storage engine\". Though typically accessed by a DBMS through the underlying operating system (and often using the operating systems' file systems as intermediates for storage layout), storage properties and configuration settings are extremely important for the efficient operation of the DBMS, and thus are closely maintained by database administrators. A DBMS, while in operation, always has its database residing in several types of storage (e.g., memory and external storage). The database data and the additional needed information, possibly in very large amounts, are coded into bits. Data typically reside in the storage in structures that look completely different from the way the data look at the conceptual and external levels, but in ways that attempt to optimize (the best possible) these levels' reconstruction when needed by users and programs, as well as for computing additional types of needed information from the data (e.g., when querying the database).",
"title": "Storage"
},
{
"paragraph_id": 61,
"text": "Some DBMSs support specifying which character encoding was used to store data, so multiple encodings can be used in the same database.",
"title": "Storage"
},
{
"paragraph_id": 62,
"text": "Various low-level database storage structures are used by the storage engine to serialize the data model so it can be written to the medium of choice. Techniques such as indexing may be used to improve performance. Conventional storage is row-oriented, but there are also column-oriented and correlation databases.",
"title": "Storage"
},
{
"paragraph_id": 63,
"text": "Often storage redundancy is employed to increase performance. A common example is storing materialized views, which consist of frequently needed external views or query results. Storing such views saves the expensive computing them each time they are needed. The downsides of materialized views are the overhead incurred when updating them to keep them synchronized with their original updated database data, and the cost of storage redundancy.",
"title": "Storage"
},
{
"paragraph_id": 64,
"text": "Occasionally a database employs storage redundancy by database objects replication (with one or more copies) to increase data availability (both to improve performance of simultaneous multiple end-user accesses to the same database object, and to provide resiliency in a case of partial failure of a distributed database). Updates of a replicated object need to be synchronized across the object copies. In many cases, the entire database is replicated.",
"title": "Storage"
},
{
"paragraph_id": 65,
"text": "With data virtualization, the data used remains in its original locations and real-time access is established to allow analytics across multiple sources. This can aid in resolving some technical difficulties such as compatibility problems when combining data from various platforms, lowering the risk of error caused by faulty data, and guaranteeing that the newest data is used. Furthermore, avoiding the creation of a new database containing personal information can make it easier to comply with privacy regulations. However, with data virtualization, the connection to all necessary data sources must be operational as there is no local copy of the data, which is one of the main drawbacks of the approach.",
"title": "Storage"
},
{
"paragraph_id": 66,
"text": "Database security deals with all various aspects of protecting the database content, its owners, and its users. It ranges from protection from intentional unauthorized database uses to unintentional database accesses by unauthorized entities (e.g., a person or a computer program).",
"title": "Security"
},
{
"paragraph_id": 67,
"text": "Database access control deals with controlling who (a person or a certain computer program) are allowed to access what information in the database. The information may comprise specific database objects (e.g., record types, specific records, data structures), certain computations over certain objects (e.g., query types, or specific queries), or using specific access paths to the former (e.g., using specific indexes or other data structures to access information). Database access controls are set by special authorized (by the database owner) personnel that uses dedicated protected security DBMS interfaces.",
"title": "Security"
},
{
"paragraph_id": 68,
"text": "This may be managed directly on an individual basis, or by the assignment of individuals and privileges to groups, or (in the most elaborate models) through the assignment of individuals and groups to roles which are then granted entitlements. Data security prevents unauthorized users from viewing or updating the database. Using passwords, users are allowed access to the entire database or subsets of it called \"subschemas\". For example, an employee database can contain all the data about an individual employee, but one group of users may be authorized to view only payroll data, while others are allowed access to only work history and medical data. If the DBMS provides a way to interactively enter and update the database, as well as interrogate it, this capability allows for managing personal databases.",
"title": "Security"
},
{
"paragraph_id": 69,
"text": "Data security in general deals with protecting specific chunks of data, both physically (i.e., from corruption, or destruction, or removal; e.g., see physical security), or the interpretation of them, or parts of them to meaningful information (e.g., by looking at the strings of bits that they comprise, concluding specific valid credit-card numbers; e.g., see data encryption).",
"title": "Security"
},
{
"paragraph_id": 70,
"text": "Change and access logging records who accessed which attributes, what was changed, and when it was changed. Logging services allow for a forensic database audit later by keeping a record of access occurrences and changes. Sometimes application-level code is used to record changes rather than leaving this in the database. Monitoring can be set up to attempt to detect security breaches. Therefore, organizations must take database security seriously because of the many benefits it provides. Organizations will be safeguarded from security breaches and hacking activities like firewall intrusion, virus spread, and ransom ware. This helps in protecting the company's essential information, which cannot be shared with outsiders at any cause.",
"title": "Security"
},
{
"paragraph_id": 71,
"text": "Database transactions can be used to introduce some level of fault tolerance and data integrity after recovery from a crash. A database transaction is a unit of work, typically encapsulating a number of operations over a database (e.g., reading a database object, writing, acquiring or releasing a lock, etc.), an abstraction supported in database and also other systems. Each transaction has well defined boundaries in terms of which program/code executions are included in that transaction (determined by the transaction's programmer via special transaction commands).",
"title": "Transactions and concurrency"
},
{
"paragraph_id": 72,
"text": "The acronym ACID describes some ideal properties of a database transaction: atomicity, consistency, isolation, and durability.",
"title": "Transactions and concurrency"
},
{
"paragraph_id": 73,
"text": "A database built with one DBMS is not portable to another DBMS (i.e., the other DBMS cannot run it). However, in some situations, it is desirable to migrate a database from one DBMS to another. The reasons are primarily economical (different DBMSs may have different total costs of ownership or TCOs), functional, and operational (different DBMSs may have different capabilities). The migration involves the database's transformation from one DBMS type to another. The transformation should maintain (if possible) the database related application (i.e., all related application programs) intact. Thus, the database's conceptual and external architectural levels should be maintained in the transformation. It may be desired that also some aspects of the architecture internal level are maintained. A complex or large database migration may be a complicated and costly (one-time) project by itself, which should be factored into the decision to migrate. This is in spite of the fact that tools may exist to help migration between specific DBMSs. Typically, a DBMS vendor provides tools to help import databases from other popular DBMSs.",
"title": "Migration"
},
{
"paragraph_id": 74,
"text": "After designing a database for an application, the next stage is building the database. Typically, an appropriate general-purpose DBMS can be selected to be used for this purpose. A DBMS provides the needed user interfaces to be used by database administrators to define the needed application's data structures within the DBMS's respective data model. Other user interfaces are used to select needed DBMS parameters (like security related, storage allocation parameters, etc.).",
"title": "Building, maintaining, and tuning"
},
{
"paragraph_id": 75,
"text": "When the database is ready (all its data structures and other needed components are defined), it is typically populated with initial application's data (database initialization, which is typically a distinct project; in many cases using specialized DBMS interfaces that support bulk insertion) before making it operational. In some cases, the database becomes operational while empty of application data, and data are accumulated during its operation.",
"title": "Building, maintaining, and tuning"
},
{
"paragraph_id": 76,
"text": "After the database is created, initialized and populated it needs to be maintained. Various database parameters may need changing and the database may need to be tuned (tuning) for better performance; application's data structures may be changed or added, new related application programs may be written to add to the application's functionality, etc.",
"title": "Building, maintaining, and tuning"
},
{
"paragraph_id": 77,
"text": "Sometimes it is desired to bring a database back to a previous state (for many reasons, e.g., cases when the database is found corrupted due to a software error, or if it has been updated with erroneous data). To achieve this, a backup operation is done occasionally or continuously, where each desired database state (i.e., the values of its data and their embedding in database's data structures) is kept within dedicated backup files (many techniques exist to do this effectively). When it is decided by a database administrator to bring the database back to this state (e.g., by specifying this state by a desired point in time when the database was in this state), these files are used to restore that state.",
"title": "Backup and restore"
},
{
"paragraph_id": 78,
"text": "Static analysis techniques for software verification can be applied also in the scenario of query languages. In particular, the *Abstract interpretation framework has been extended to the field of query languages for relational databases as a way to support sound approximation techniques. The semantics of query languages can be tuned according to suitable abstractions of the concrete domain of data. The abstraction of relational database systems has many interesting applications, in particular, for security purposes, such as fine-grained access control, watermarking, etc.",
"title": "Static analysis"
},
{
"paragraph_id": 79,
"text": "Other DBMS features might include:",
"title": "Miscellaneous features"
},
{
"paragraph_id": 80,
"text": "Increasingly, there are calls for a single system that incorporates all of these core functionalities into the same build, test, and deployment framework for database management and source control. Borrowing from other developments in the software industry, some market such offerings as \"DevOps for database\".",
"title": "Miscellaneous features"
},
{
"paragraph_id": 81,
"text": "The first task of a database designer is to produce a conceptual data model that reflects the structure of the information to be held in the database. A common approach to this is to develop an entity–relationship model, often with the aid of drawing tools. Another popular approach is the Unified Modeling Language. A successful data model will accurately reflect the possible state of the external world being modeled: for example, if people can have more than one phone number, it will allow this information to be captured. Designing a good conceptual data model requires a good understanding of the application domain; it typically involves asking deep questions about the things of interest to an organization, like \"can a customer also be a supplier?\", or \"if a product is sold with two different forms of packaging, are those the same product or different products?\", or \"if a plane flies from New York to Dubai via Frankfurt, is that one flight or two (or maybe even three)?\". The answers to these questions establish definitions of the terminology used for entities (customers, products, flights, flight segments) and their relationships and attributes.",
"title": "Design and modeling"
},
{
"paragraph_id": 82,
"text": "Producing the conceptual data model sometimes involves input from business processes, or the analysis of workflow in the organization. This can help to establish what information is needed in the database, and what can be left out. For example, it can help when deciding whether the database needs to hold historic data as well as current data.",
"title": "Design and modeling"
},
{
"paragraph_id": 83,
"text": "Having produced a conceptual data model that users are happy with, the next stage is to translate this into a schema that implements the relevant data structures within the database. This process is often called logical database design, and the output is a logical data model expressed in the form of a schema. Whereas the conceptual data model is (in theory at least) independent of the choice of database technology, the logical data model will be expressed in terms of a particular database model supported by the chosen DBMS. (The terms data model and database model are often used interchangeably, but in this article we use data model for the design of a specific database, and database model for the modeling notation used to express that design).",
"title": "Design and modeling"
},
{
"paragraph_id": 84,
"text": "The most popular database model for general-purpose databases is the relational model, or more precisely, the relational model as represented by the SQL language. The process of creating a logical database design using this model uses a methodical approach known as normalization. The goal of normalization is to ensure that each elementary \"fact\" is only recorded in one place, so that insertions, updates, and deletions automatically maintain consistency.",
"title": "Design and modeling"
},
{
"paragraph_id": 85,
"text": "The final stage of database design is to make the decisions that affect performance, scalability, recovery, security, and the like, which depend on the particular DBMS. This is often called physical database design, and the output is the physical data model. A key goal during this stage is data independence, meaning that the decisions made for performance optimization purposes should be invisible to end-users and applications. There are two types of data independence: Physical data independence and logical data independence. Physical design is driven mainly by performance requirements, and requires a good knowledge of the expected workload and access patterns, and a deep understanding of the features offered by the chosen DBMS.",
"title": "Design and modeling"
},
{
"paragraph_id": 86,
"text": "Another aspect of physical database design is security. It involves both defining access control to database objects as well as defining security levels and methods for the data itself.",
"title": "Design and modeling"
},
{
"paragraph_id": 87,
"text": "A database model is a type of data model that determines the logical structure of a database and fundamentally determines in which manner data can be stored, organized, and manipulated. The most popular example of a database model is the relational model (or the SQL approximation of relational), which uses a table-based format.",
"title": "Design and modeling"
},
{
"paragraph_id": 88,
"text": "Common logical data models for databases include:",
"title": "Design and modeling"
},
{
"paragraph_id": 89,
"text": "An object–relational database combines the two related structures.",
"title": "Design and modeling"
},
{
"paragraph_id": 90,
"text": "Physical data models include:",
"title": "Design and modeling"
},
{
"paragraph_id": 91,
"text": "Other models include:",
"title": "Design and modeling"
},
{
"paragraph_id": 92,
"text": "Specialized models are optimized for particular types of data:",
"title": "Design and modeling"
},
{
"paragraph_id": 93,
"text": "A database management system provides three views of the database data:",
"title": "Design and modeling"
},
{
"paragraph_id": 94,
"text": "While there is typically only one conceptual and internal view of the data, there can be any number of different external views. This allows users to see database information in a more business-related way rather than from a technical, processing viewpoint. For example, a financial department of a company needs the payment details of all employees as part of the company's expenses, but does not need details about employees that are in the interest of the human resources department. Thus different departments need different views of the company's database.",
"title": "Design and modeling"
},
{
"paragraph_id": 95,
"text": "The three-level database architecture relates to the concept of data independence which was one of the major initial driving forces of the relational model. The idea is that changes made at a certain level do not affect the view at a higher level. For example, changes in the internal level do not affect application programs written using conceptual level interfaces, which reduces the impact of making physical changes to improve performance.",
"title": "Design and modeling"
},
{
"paragraph_id": 96,
"text": "The conceptual view provides a level of indirection between internal and external. On the one hand it provides a common view of the database, independent of different external view structures, and on the other hand it abstracts away details of how the data are stored or managed (internal level). In principle every level, and even every external view, can be presented by a different data model. In practice usually a given DBMS uses the same data model for both the external and the conceptual levels (e.g., relational model). The internal level, which is hidden inside the DBMS and depends on its implementation, requires a different level of detail and uses its own types of data structure types.",
"title": "Design and modeling"
},
{
"paragraph_id": 97,
"text": "Database technology has been an active research topic since the 1960s, both in academia and in the research and development groups of companies (for example IBM Research). Research activity includes theory and development of prototypes. Notable research topics have included models, the atomic transaction concept, related concurrency control techniques, query languages and query optimization methods, RAID, and more.",
"title": "Research"
},
{
"paragraph_id": 98,
"text": "The database research area has several dedicated academic journals (for example, ACM Transactions on Database Systems-TODS, Data and Knowledge Engineering-DKE) and annual conferences (e.g., ACM SIGMOD, ACM PODS, VLDB, IEEE ICDE).",
"title": "Research"
}
] | In computing, a database is an organized collection of data or a type of data store based on the use of a database management system (DBMS), the software that interacts with end users, applications, and the database itself to capture and analyze the data. The DBMS additionally encompasses the core facilities provided to administer the database. The sum total of the database, the DBMS and the associated applications can be referred to as a database system. Often the term "database" is also used loosely to refer to any of the DBMS, the database system or an application associated with the database. Small databases can be stored on a file system, while large databases are hosted on computer clusters or cloud storage. The design of databases spans formal techniques and practical considerations, including data modeling, efficient data representation and storage, query languages, security and privacy of sensitive data, and distributed computing issues, including supporting concurrent access and fault tolerance. Computer scientists may classify database management systems according to the database models that they support. Relational databases became dominant in the 1980s. These model data as rows and columns in a series of tables, and the vast majority use SQL for writing and querying data. In the 2000s, non-relational databases became popular, collectively referred to as NoSQL, because they use different query languages. | 2001-09-25T19:32:49Z | 2023-12-12T17:34:15Z | [
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8,378 | Dipole | In physics, a dipole (from Greek δίς (dis) 'twice', and πόλος (polos) 'axis') is an electromagnetic phenomenon which occurs in two ways:
Dipoles, whether electric or magnetic, can be characterized by their dipole moment, a vector quantity. For the simple electric dipole, the electric dipole moment points from the negative charge towards the positive charge, and has a magnitude equal to the strength of each charge times the separation between the charges. (To be precise: for the definition of the dipole moment, one should always consider the "dipole limit", where, for example, the distance of the generating charges should converge to 0 while simultaneously, the charge strength should diverge to infinity in such a way that the product remains a positive constant.)
For the magnetic (dipole) current loop, the magnetic dipole moment points through the loop (according to the right hand grip rule), with a magnitude equal to the current in the loop times the area of the loop.
Similar to magnetic current loops, the electron particle and some other fundamental particles have magnetic dipole moments, as an electron generates a magnetic field identical to that generated by a very small current loop. However, an electron's magnetic dipole moment is not due to a current loop, but to an intrinsic property of the electron. The electron may also have an electric dipole moment though such has yet to be observed (see electron electric dipole moment).
A permanent magnet, such as a bar magnet, owes its magnetism to the intrinsic magnetic dipole moment of the electron. The two ends of a bar magnet are referred to as poles (not to be confused with monopoles, see Classification below) and may be labeled "north" and "south". In terms of the Earth's magnetic field, they are respectively "north-seeking" and "south-seeking" poles: if the magnet were freely suspended in the Earth's magnetic field, the north-seeking pole would point towards the north and the south-seeking pole would point towards the south. The dipole moment of the bar magnet points from its magnetic south to its magnetic north pole. In a magnetic compass, the north pole of a bar magnet points north. However, that means that Earth's geomagnetic north pole is the south pole (south-seeking pole) of its dipole moment and vice versa.
The only known mechanisms for the creation of magnetic dipoles are by current loops or quantum-mechanical spin since the existence of magnetic monopoles has never been experimentally demonstrated.
A physical dipole consists of two equal and opposite point charges: in the literal sense, two poles. Its field at large distances (i.e., distances large in comparison to the separation of the poles) depends almost entirely on the dipole moment as defined above. A point (electric) dipole is the limit obtained by letting the separation tend to 0 while keeping the dipole moment fixed. The field of a point dipole has a particularly simple form, and the order-1 term in the multipole expansion is precisely the point dipole field.
Although there are no known magnetic monopoles in nature, there are magnetic dipoles in the form of the quantum-mechanical spin associated with particles such as electrons (although the accurate description of such effects falls outside of classical electromagnetism). A theoretical magnetic point dipole has a magnetic field of exactly the same form as the electric field of an electric point dipole. A very small current-carrying loop is approximately a magnetic point dipole; the magnetic dipole moment of such a loop is the product of the current flowing in the loop and the (vector) area of the loop.
Any configuration of charges or currents has a 'dipole moment', which describes the dipole whose field is the best approximation, at large distances, to that of the given configuration. This is simply one term in the multipole expansion when the total charge ("monopole moment") is 0—as it always is for the magnetic case, since there are no magnetic monopoles. The dipole term is the dominant one at large distances: Its field falls off in proportion to 1/r, as compared to 1/r for the next (quadrupole) term and higher powers of 1/r for higher terms, or 1/r for the monopole term.
Many molecules have such dipole moments due to non-uniform distributions of positive and negative charges on the various atoms. Such is the case with polar compounds like hydrogen fluoride (HF), where electron density is shared unequally between atoms. Therefore, a molecule's dipole is an electric dipole with an inherent electric field that should not be confused with a magnetic dipole, which generates a magnetic field.
The physical chemist Peter J. W. Debye was the first scientist to study molecular dipoles extensively, and, as a consequence, dipole moments are measured in the non-SI unit named debye in his honor.
For molecules there are three types of dipoles:
More generally, an induced dipole of any polarizable charge distribution ρ (remember that a molecule has a charge distribution) is caused by an electric field external to ρ. This field may, for instance, originate from an ion or polar molecule in the vicinity of ρ or may be macroscopic (e.g., a molecule between the plates of a charged capacitor). The size of the induced dipole moment is equal to the product of the strength of the external field and the dipole polarizability of ρ.
Dipole moment values can be obtained from measurement of the dielectric constant. Some typical gas phase values in debye units are:
Potassium bromide (KBr) has one of the highest dipole moments because it is an ionic compound that exists as a molecule in the gas phase.
The overall dipole moment of a molecule may be approximated as a vector sum of bond dipole moments. As a vector sum it depends on the relative orientation of the bonds, so that from the dipole moment information can be deduced about the molecular geometry.
For example, the zero dipole of CO2 implies that the two C=O bond dipole moments cancel so that the molecule must be linear. For H2O the O−H bond moments do not cancel because the molecule is bent. For ozone (O3) which is also a bent molecule, the bond dipole moments are not zero even though the O−O bonds are between similar atoms. This agrees with the Lewis structures for the resonance forms of ozone which show a positive charge on the central oxygen atom.
An example in organic chemistry of the role of geometry in determining dipole moment is the cis and trans isomers of 1,2-dichloroethene. In the cis isomer the two polar C−Cl bonds are on the same side of the C=C double bond and the molecular dipole moment is 1.90 D. In the trans isomer, the dipole moment is zero because the two C−Cl bonds are on opposite sides of the C=C and cancel (and the two bond moments for the much less polar C−H bonds also cancel).
Another example of the role of molecular geometry is boron trifluoride, which has three polar bonds with a difference in electronegativity greater than the traditionally cited threshold of 1.7 for ionic bonding. However, due to the equilateral triangular distribution of the fluoride ions centered on and in the same plane as the boron cation, the symmetry of the molecule results in its dipole moment being zero.
Consider a collection of N particles with charges qi and position vectors ri. For instance, this collection may be a molecule consisting of electrons, all with charge −e, and nuclei with charge eZi, where Zi is the atomic number of the i th nucleus. The dipole observable (physical quantity) has the quantum mechanical dipole operator:
Notice that this definition is valid only for neutral atoms or molecules, i.e. total charge equal to zero. In the ionized case, we have
where r c {\displaystyle \mathbf {r} _{c}} is the center of mass of the molecule/group of particles.
A non-degenerate (S-state) atom can have only a zero permanent dipole. This fact follows quantum mechanically from the inversion symmetry of atoms. All 3 components of the dipole operator are antisymmetric under inversion with respect to the nucleus,
where p {\displaystyle {\mathfrak {p}}} is the dipole operator and I {\displaystyle {\mathfrak {I}}} is the inversion operator.
The permanent dipole moment of an atom in a non-degenerate state (see degenerate energy level) is given as the expectation (average) value of the dipole operator,
where | S ⟩ {\displaystyle |\,S\,\rangle } is an S-state, non-degenerate, wavefunction, which is symmetric or antisymmetric under inversion: I | S ⟩ = ± | S ⟩ {\displaystyle {\mathfrak {I}}\,|\,S\,\rangle =\pm |\,S\,\rangle } . Since the product of the wavefunction (in the ket) and its complex conjugate (in the bra) is always symmetric under inversion and its inverse,
it follows that the expectation value changes sign under inversion. We used here the fact that I {\displaystyle {\mathfrak {I}}} , being a symmetry operator, is unitary: I − 1 = I ∗ {\displaystyle {\mathfrak {I}}^{-1}={\mathfrak {I}}^{*}\,} and by definition the Hermitian adjoint I ∗ {\displaystyle {\mathfrak {I}}^{*}\,} may be moved from bra to ket and then becomes I ∗ ∗ = I {\displaystyle {\mathfrak {I}}^{**}={\mathfrak {I}}\,} . Since the only quantity that is equal to minus itself is the zero, the expectation value vanishes,
In the case of open-shell atoms with degenerate energy levels, one could define a dipole moment by the aid of the first-order Stark effect. This gives a non-vanishing dipole (by definition proportional to a non-vanishing first-order Stark shift) only if some of the wavefunctions belonging to the degenerate energies have opposite parity; i.e., have different behavior under inversion. This is a rare occurrence, but happens for the excited H-atom, where 2s and 2p states are "accidentally" degenerate (see article Laplace–Runge–Lenz vector for the origin of this degeneracy) and have opposite parity (2s is even and 2p is odd).
The far-field strength, B, of a dipole magnetic field is given by
where
Conversion to cylindrical coordinates is achieved using r = z + ρ and
where ρ is the perpendicular distance from the z-axis. Then,
The field itself is a vector quantity:
where
This is exactly the field of a point dipole, exactly the dipole term in the multipole expansion of an arbitrary field, and approximately the field of any dipole-like configuration at large distances.
The vector potential A of a magnetic dipole is
with the same definitions as above.
The electrostatic potential at position r due to an electric dipole at the origin is given by:
where p is the (vector) dipole moment, and є0 is the permittivity of free space.
This term appears as the second term in the multipole expansion of an arbitrary electrostatic potential Φ(r). If the source of Φ(r) is a dipole, as it is assumed here, this term is the only non-vanishing term in the multipole expansion of Φ(r). The electric field from a dipole can be found from the gradient of this potential:
This is of the same form of the expression for the magnetic field of a point magnetic dipole, ignoring the delta function. In a real electric dipole, however, the charges are physically separate and the electric field diverges or converges at the point charges. This is different to the magnetic field of a real magnetic dipole which is continuous everywhere. The delta function represents the strong field pointing in the opposite direction between the point charges, which is often omitted since one is rarely interested in the field at the dipole's position. For further discussions about the internal field of dipoles, see or Magnetic moment#Internal magnetic field of a dipole.
Since the direction of an electric field is defined as the direction of the force on a positive charge, electric field lines point away from a positive charge and toward a negative charge.
When placed in a homogeneous electric or magnetic field, equal but opposite forces arise on each side of the dipole creating a torque τ}:
for an electric dipole moment p (in coulomb-meters), or
for a magnetic dipole moment m (in ampere-square meters).
The resulting torque will tend to align the dipole with the applied field, which in the case of an electric dipole, yields a potential energy of
The energy of a magnetic dipole is similarly
In addition to dipoles in electrostatics, it is also common to consider an electric or magnetic dipole that is oscillating in time. It is an extension, or a more physical next-step, to spherical wave radiation.
In particular, consider a harmonically oscillating electric dipole, with angular frequency ω and a dipole moment p0 along the ẑ direction of the form
In vacuum, the exact field produced by this oscillating dipole can be derived using the retarded potential formulation as:
For rω/c ≫ 1, the far-field takes the simpler form of a radiating "spherical" wave, but with angular dependence embedded in the cross-product:
The time-averaged Poynting vector
is not distributed isotropically, but concentrated around the directions lying perpendicular to the dipole moment, as a result of the non-spherical electric and magnetic waves. In fact, the spherical harmonic function (sin θ) responsible for such toroidal angular distribution is precisely the l = 1 "p" wave.
The total time-average power radiated by the field can then be derived from the Poynting vector as
Notice that the dependence of the power on the fourth power of the frequency of the radiation is in accordance with the Rayleigh scattering, and the underlying effects why the sky consists of mainly blue colour.
A circular polarized dipole is described as a superposition of two linear dipoles. | [
{
"paragraph_id": 0,
"text": "In physics, a dipole (from Greek δίς (dis) 'twice', and πόλος (polos) 'axis') is an electromagnetic phenomenon which occurs in two ways:",
"title": ""
},
{
"paragraph_id": 1,
"text": "Dipoles, whether electric or magnetic, can be characterized by their dipole moment, a vector quantity. For the simple electric dipole, the electric dipole moment points from the negative charge towards the positive charge, and has a magnitude equal to the strength of each charge times the separation between the charges. (To be precise: for the definition of the dipole moment, one should always consider the \"dipole limit\", where, for example, the distance of the generating charges should converge to 0 while simultaneously, the charge strength should diverge to infinity in such a way that the product remains a positive constant.)",
"title": ""
},
{
"paragraph_id": 2,
"text": "For the magnetic (dipole) current loop, the magnetic dipole moment points through the loop (according to the right hand grip rule), with a magnitude equal to the current in the loop times the area of the loop.",
"title": ""
},
{
"paragraph_id": 3,
"text": "Similar to magnetic current loops, the electron particle and some other fundamental particles have magnetic dipole moments, as an electron generates a magnetic field identical to that generated by a very small current loop. However, an electron's magnetic dipole moment is not due to a current loop, but to an intrinsic property of the electron. The electron may also have an electric dipole moment though such has yet to be observed (see electron electric dipole moment).",
"title": ""
},
{
"paragraph_id": 4,
"text": "A permanent magnet, such as a bar magnet, owes its magnetism to the intrinsic magnetic dipole moment of the electron. The two ends of a bar magnet are referred to as poles (not to be confused with monopoles, see Classification below) and may be labeled \"north\" and \"south\". In terms of the Earth's magnetic field, they are respectively \"north-seeking\" and \"south-seeking\" poles: if the magnet were freely suspended in the Earth's magnetic field, the north-seeking pole would point towards the north and the south-seeking pole would point towards the south. The dipole moment of the bar magnet points from its magnetic south to its magnetic north pole. In a magnetic compass, the north pole of a bar magnet points north. However, that means that Earth's geomagnetic north pole is the south pole (south-seeking pole) of its dipole moment and vice versa.",
"title": ""
},
{
"paragraph_id": 5,
"text": "The only known mechanisms for the creation of magnetic dipoles are by current loops or quantum-mechanical spin since the existence of magnetic monopoles has never been experimentally demonstrated.",
"title": ""
},
{
"paragraph_id": 6,
"text": "A physical dipole consists of two equal and opposite point charges: in the literal sense, two poles. Its field at large distances (i.e., distances large in comparison to the separation of the poles) depends almost entirely on the dipole moment as defined above. A point (electric) dipole is the limit obtained by letting the separation tend to 0 while keeping the dipole moment fixed. The field of a point dipole has a particularly simple form, and the order-1 term in the multipole expansion is precisely the point dipole field.",
"title": "Classification"
},
{
"paragraph_id": 7,
"text": "Although there are no known magnetic monopoles in nature, there are magnetic dipoles in the form of the quantum-mechanical spin associated with particles such as electrons (although the accurate description of such effects falls outside of classical electromagnetism). A theoretical magnetic point dipole has a magnetic field of exactly the same form as the electric field of an electric point dipole. A very small current-carrying loop is approximately a magnetic point dipole; the magnetic dipole moment of such a loop is the product of the current flowing in the loop and the (vector) area of the loop.",
"title": "Classification"
},
{
"paragraph_id": 8,
"text": "Any configuration of charges or currents has a 'dipole moment', which describes the dipole whose field is the best approximation, at large distances, to that of the given configuration. This is simply one term in the multipole expansion when the total charge (\"monopole moment\") is 0—as it always is for the magnetic case, since there are no magnetic monopoles. The dipole term is the dominant one at large distances: Its field falls off in proportion to 1/r, as compared to 1/r for the next (quadrupole) term and higher powers of 1/r for higher terms, or 1/r for the monopole term.",
"title": "Classification"
},
{
"paragraph_id": 9,
"text": "Many molecules have such dipole moments due to non-uniform distributions of positive and negative charges on the various atoms. Such is the case with polar compounds like hydrogen fluoride (HF), where electron density is shared unequally between atoms. Therefore, a molecule's dipole is an electric dipole with an inherent electric field that should not be confused with a magnetic dipole, which generates a magnetic field.",
"title": "Molecular dipoles"
},
{
"paragraph_id": 10,
"text": "The physical chemist Peter J. W. Debye was the first scientist to study molecular dipoles extensively, and, as a consequence, dipole moments are measured in the non-SI unit named debye in his honor.",
"title": "Molecular dipoles"
},
{
"paragraph_id": 11,
"text": "For molecules there are three types of dipoles:",
"title": "Molecular dipoles"
},
{
"paragraph_id": 12,
"text": "More generally, an induced dipole of any polarizable charge distribution ρ (remember that a molecule has a charge distribution) is caused by an electric field external to ρ. This field may, for instance, originate from an ion or polar molecule in the vicinity of ρ or may be macroscopic (e.g., a molecule between the plates of a charged capacitor). The size of the induced dipole moment is equal to the product of the strength of the external field and the dipole polarizability of ρ.",
"title": "Molecular dipoles"
},
{
"paragraph_id": 13,
"text": "Dipole moment values can be obtained from measurement of the dielectric constant. Some typical gas phase values in debye units are:",
"title": "Molecular dipoles"
},
{
"paragraph_id": 14,
"text": "Potassium bromide (KBr) has one of the highest dipole moments because it is an ionic compound that exists as a molecule in the gas phase.",
"title": "Molecular dipoles"
},
{
"paragraph_id": 15,
"text": "The overall dipole moment of a molecule may be approximated as a vector sum of bond dipole moments. As a vector sum it depends on the relative orientation of the bonds, so that from the dipole moment information can be deduced about the molecular geometry.",
"title": "Molecular dipoles"
},
{
"paragraph_id": 16,
"text": "For example, the zero dipole of CO2 implies that the two C=O bond dipole moments cancel so that the molecule must be linear. For H2O the O−H bond moments do not cancel because the molecule is bent. For ozone (O3) which is also a bent molecule, the bond dipole moments are not zero even though the O−O bonds are between similar atoms. This agrees with the Lewis structures for the resonance forms of ozone which show a positive charge on the central oxygen atom.",
"title": "Molecular dipoles"
},
{
"paragraph_id": 17,
"text": "An example in organic chemistry of the role of geometry in determining dipole moment is the cis and trans isomers of 1,2-dichloroethene. In the cis isomer the two polar C−Cl bonds are on the same side of the C=C double bond and the molecular dipole moment is 1.90 D. In the trans isomer, the dipole moment is zero because the two C−Cl bonds are on opposite sides of the C=C and cancel (and the two bond moments for the much less polar C−H bonds also cancel).",
"title": "Molecular dipoles"
},
{
"paragraph_id": 18,
"text": "Another example of the role of molecular geometry is boron trifluoride, which has three polar bonds with a difference in electronegativity greater than the traditionally cited threshold of 1.7 for ionic bonding. However, due to the equilateral triangular distribution of the fluoride ions centered on and in the same plane as the boron cation, the symmetry of the molecule results in its dipole moment being zero.",
"title": "Molecular dipoles"
},
{
"paragraph_id": 19,
"text": "Consider a collection of N particles with charges qi and position vectors ri. For instance, this collection may be a molecule consisting of electrons, all with charge −e, and nuclei with charge eZi, where Zi is the atomic number of the i th nucleus. The dipole observable (physical quantity) has the quantum mechanical dipole operator:",
"title": "Quantum mechanical dipole operator"
},
{
"paragraph_id": 20,
"text": "Notice that this definition is valid only for neutral atoms or molecules, i.e. total charge equal to zero. In the ionized case, we have",
"title": "Quantum mechanical dipole operator"
},
{
"paragraph_id": 21,
"text": "where r c {\\displaystyle \\mathbf {r} _{c}} is the center of mass of the molecule/group of particles.",
"title": "Quantum mechanical dipole operator"
},
{
"paragraph_id": 22,
"text": "A non-degenerate (S-state) atom can have only a zero permanent dipole. This fact follows quantum mechanically from the inversion symmetry of atoms. All 3 components of the dipole operator are antisymmetric under inversion with respect to the nucleus,",
"title": "Atomic dipoles"
},
{
"paragraph_id": 23,
"text": "where p {\\displaystyle {\\mathfrak {p}}} is the dipole operator and I {\\displaystyle {\\mathfrak {I}}} is the inversion operator.",
"title": "Atomic dipoles"
},
{
"paragraph_id": 24,
"text": "The permanent dipole moment of an atom in a non-degenerate state (see degenerate energy level) is given as the expectation (average) value of the dipole operator,",
"title": "Atomic dipoles"
},
{
"paragraph_id": 25,
"text": "where | S ⟩ {\\displaystyle |\\,S\\,\\rangle } is an S-state, non-degenerate, wavefunction, which is symmetric or antisymmetric under inversion: I | S ⟩ = ± | S ⟩ {\\displaystyle {\\mathfrak {I}}\\,|\\,S\\,\\rangle =\\pm |\\,S\\,\\rangle } . Since the product of the wavefunction (in the ket) and its complex conjugate (in the bra) is always symmetric under inversion and its inverse,",
"title": "Atomic dipoles"
},
{
"paragraph_id": 26,
"text": "it follows that the expectation value changes sign under inversion. We used here the fact that I {\\displaystyle {\\mathfrak {I}}} , being a symmetry operator, is unitary: I − 1 = I ∗ {\\displaystyle {\\mathfrak {I}}^{-1}={\\mathfrak {I}}^{*}\\,} and by definition the Hermitian adjoint I ∗ {\\displaystyle {\\mathfrak {I}}^{*}\\,} may be moved from bra to ket and then becomes I ∗ ∗ = I {\\displaystyle {\\mathfrak {I}}^{**}={\\mathfrak {I}}\\,} . Since the only quantity that is equal to minus itself is the zero, the expectation value vanishes,",
"title": "Atomic dipoles"
},
{
"paragraph_id": 27,
"text": "In the case of open-shell atoms with degenerate energy levels, one could define a dipole moment by the aid of the first-order Stark effect. This gives a non-vanishing dipole (by definition proportional to a non-vanishing first-order Stark shift) only if some of the wavefunctions belonging to the degenerate energies have opposite parity; i.e., have different behavior under inversion. This is a rare occurrence, but happens for the excited H-atom, where 2s and 2p states are \"accidentally\" degenerate (see article Laplace–Runge–Lenz vector for the origin of this degeneracy) and have opposite parity (2s is even and 2p is odd).",
"title": "Atomic dipoles"
},
{
"paragraph_id": 28,
"text": "The far-field strength, B, of a dipole magnetic field is given by",
"title": "Field of a static magnetic dipole"
},
{
"paragraph_id": 29,
"text": "where",
"title": "Field of a static magnetic dipole"
},
{
"paragraph_id": 30,
"text": "Conversion to cylindrical coordinates is achieved using r = z + ρ and",
"title": "Field of a static magnetic dipole"
},
{
"paragraph_id": 31,
"text": "where ρ is the perpendicular distance from the z-axis. Then,",
"title": "Field of a static magnetic dipole"
},
{
"paragraph_id": 32,
"text": "The field itself is a vector quantity:",
"title": "Field of a static magnetic dipole"
},
{
"paragraph_id": 33,
"text": "where",
"title": "Field of a static magnetic dipole"
},
{
"paragraph_id": 34,
"text": "This is exactly the field of a point dipole, exactly the dipole term in the multipole expansion of an arbitrary field, and approximately the field of any dipole-like configuration at large distances.",
"title": "Field of a static magnetic dipole"
},
{
"paragraph_id": 35,
"text": "The vector potential A of a magnetic dipole is",
"title": "Field of a static magnetic dipole"
},
{
"paragraph_id": 36,
"text": "with the same definitions as above.",
"title": "Field of a static magnetic dipole"
},
{
"paragraph_id": 37,
"text": "The electrostatic potential at position r due to an electric dipole at the origin is given by:",
"title": "Field from an electric dipole"
},
{
"paragraph_id": 38,
"text": "where p is the (vector) dipole moment, and є0 is the permittivity of free space.",
"title": "Field from an electric dipole"
},
{
"paragraph_id": 39,
"text": "This term appears as the second term in the multipole expansion of an arbitrary electrostatic potential Φ(r). If the source of Φ(r) is a dipole, as it is assumed here, this term is the only non-vanishing term in the multipole expansion of Φ(r). The electric field from a dipole can be found from the gradient of this potential:",
"title": "Field from an electric dipole"
},
{
"paragraph_id": 40,
"text": "This is of the same form of the expression for the magnetic field of a point magnetic dipole, ignoring the delta function. In a real electric dipole, however, the charges are physically separate and the electric field diverges or converges at the point charges. This is different to the magnetic field of a real magnetic dipole which is continuous everywhere. The delta function represents the strong field pointing in the opposite direction between the point charges, which is often omitted since one is rarely interested in the field at the dipole's position. For further discussions about the internal field of dipoles, see or Magnetic moment#Internal magnetic field of a dipole.",
"title": "Field from an electric dipole"
},
{
"paragraph_id": 41,
"text": "Since the direction of an electric field is defined as the direction of the force on a positive charge, electric field lines point away from a positive charge and toward a negative charge.",
"title": "Torque on a dipole"
},
{
"paragraph_id": 42,
"text": "When placed in a homogeneous electric or magnetic field, equal but opposite forces arise on each side of the dipole creating a torque τ}:",
"title": "Torque on a dipole"
},
{
"paragraph_id": 43,
"text": "for an electric dipole moment p (in coulomb-meters), or",
"title": "Torque on a dipole"
},
{
"paragraph_id": 44,
"text": "for a magnetic dipole moment m (in ampere-square meters).",
"title": "Torque on a dipole"
},
{
"paragraph_id": 45,
"text": "The resulting torque will tend to align the dipole with the applied field, which in the case of an electric dipole, yields a potential energy of",
"title": "Torque on a dipole"
},
{
"paragraph_id": 46,
"text": "The energy of a magnetic dipole is similarly",
"title": "Torque on a dipole"
},
{
"paragraph_id": 47,
"text": "In addition to dipoles in electrostatics, it is also common to consider an electric or magnetic dipole that is oscillating in time. It is an extension, or a more physical next-step, to spherical wave radiation.",
"title": "Dipole radiation"
},
{
"paragraph_id": 48,
"text": "In particular, consider a harmonically oscillating electric dipole, with angular frequency ω and a dipole moment p0 along the ẑ direction of the form",
"title": "Dipole radiation"
},
{
"paragraph_id": 49,
"text": "In vacuum, the exact field produced by this oscillating dipole can be derived using the retarded potential formulation as:",
"title": "Dipole radiation"
},
{
"paragraph_id": 50,
"text": "For rω/c ≫ 1, the far-field takes the simpler form of a radiating \"spherical\" wave, but with angular dependence embedded in the cross-product:",
"title": "Dipole radiation"
},
{
"paragraph_id": 51,
"text": "The time-averaged Poynting vector",
"title": "Dipole radiation"
},
{
"paragraph_id": 52,
"text": "is not distributed isotropically, but concentrated around the directions lying perpendicular to the dipole moment, as a result of the non-spherical electric and magnetic waves. In fact, the spherical harmonic function (sin θ) responsible for such toroidal angular distribution is precisely the l = 1 \"p\" wave.",
"title": "Dipole radiation"
},
{
"paragraph_id": 53,
"text": "The total time-average power radiated by the field can then be derived from the Poynting vector as",
"title": "Dipole radiation"
},
{
"paragraph_id": 54,
"text": "Notice that the dependence of the power on the fourth power of the frequency of the radiation is in accordance with the Rayleigh scattering, and the underlying effects why the sky consists of mainly blue colour.",
"title": "Dipole radiation"
},
{
"paragraph_id": 55,
"text": "A circular polarized dipole is described as a superposition of two linear dipoles.",
"title": "Dipole radiation"
}
] | In physics, a dipole is an electromagnetic phenomenon which occurs in two ways: An electric dipole deals with the separation of the positive and negative electric charges found in any electromagnetic system. A simple example of this system is a pair of charges of equal magnitude but opposite sign separated by some typically small distance.
A magnetic dipole is the closed circulation of an electric current system. A simple example is a single loop of wire with constant current through it. A bar magnet is an example of a magnet with a permanent magnetic dipole moment. Dipoles, whether electric or magnetic, can be characterized by their dipole moment, a vector quantity. For the simple electric dipole, the electric dipole moment points from the negative charge towards the positive charge, and has a magnitude equal to the strength of each charge times the separation between the charges. For the magnetic (dipole) current loop, the magnetic dipole moment points through the loop, with a magnitude equal to the current in the loop times the area of the loop. Similar to magnetic current loops, the electron particle and some other fundamental particles have magnetic dipole moments, as an electron generates a magnetic field identical to that generated by a very small current loop. However, an electron's magnetic dipole moment is not due to a current loop, but to an intrinsic property of the electron. The electron may also have an electric dipole moment though such has yet to be observed. A permanent magnet, such as a bar magnet, owes its magnetism to the intrinsic magnetic dipole moment of the electron. The two ends of a bar magnet are referred to as poles and may be labeled "north" and "south". In terms of the Earth's magnetic field, they are respectively "north-seeking" and "south-seeking" poles: if the magnet were freely suspended in the Earth's magnetic field, the north-seeking pole would point towards the north and the south-seeking pole would point towards the south. The dipole moment of the bar magnet points from its magnetic south to its magnetic north pole. In a magnetic compass, the north pole of a bar magnet points north. However, that means that Earth's geomagnetic north pole is the south pole of its dipole moment and vice versa. The only known mechanisms for the creation of magnetic dipoles are by current loops or quantum-mechanical spin since the existence of magnetic monopoles has never been experimentally demonstrated. | 2001-09-02T10:38:54Z | 2023-12-03T20:54:05Z | [
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8,386 | Dynamics | Dynamics (from Greek δυναμικός dynamikos "powerful", from δύναμις dynamis "power") or dynamic may refer to:
Internet
Mathematics | [
{
"paragraph_id": 0,
"text": "Dynamics (from Greek δυναμικός dynamikos \"powerful\", from δύναμις dynamis \"power\") or dynamic may refer to:",
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},
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"text": "Internet",
"title": "Computer science and mathematics"
},
{
"paragraph_id": 2,
"text": "Mathematics",
"title": "Computer science and mathematics"
}
] | Dynamics or dynamic may refer to: | 2001-09-04T17:56:58Z | 2023-12-08T16:37:52Z | [
"Template:In title",
"Template:Disambiguation",
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"Template:TOC right",
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] | https://en.wikipedia.org/wiki/Dynamics |
8,387 | Draught beer | Draught beer, also spelt draft, is beer served from a cask or keg rather than from a bottle or can. Draught beer served from a pressurised keg is also known as keg beer.
Until Joseph Bramah patented the beer engine in 1785, beer was served directly from the barrel and carried to the customer. The Old English dragan ("carry; pull") developed into a series of related words including drag, draw, and draught. By the time Bramah's beer pumps became popular, the use of the term draught to refer to the acts of serving or drinking beer was well established and transferred easily to beer served via the hand pumps. In time, the word came to be restricted to only such beer. The usual spelling is now "draught" in the United Kingdom, Ireland, Australia, and New Zealand and more commonly "draft" in North America, although it can be spelt either way. Regardless of spelling, the word is pronounced /drɑːft/ or /dræft/ depending on the region the speaker is from.
Canned draught is beer served from a pressurised container featuring a widget. Smooth flow (also known as cream flow, nitrokeg, or smooth) is the name brewers give to draught beers pressurised with a partial nitrogen gas blend.
In 1691, an article in the London Gazette mentioned John Lofting, who held a patent for a fire engine: "The said patentee has also projected a very useful engine for starting of beer, and other liquors which will draw from 20 to 30 barrels an hour, which are completely fixed with brass joints and screws at reasonable rates".
In the early 20th century, draught beer started to be served from pressurised containers. Artificial carbonation was introduced in the United Kingdom in 1936, with Watney's experimental pasteurised beer Red Barrel. Though this method of serving beer did not take hold in the UK until the late 1950s, it did become the favored method in the rest of Europe, where it is known by such terms as en pression. The carbonation method of serving beer subsequently spread to the rest of the world; by the early 1970s the term "draught beer" almost exclusively referred to beer served under pressure as opposed to the traditional cask or barrel beer.
In Britain, the Campaign for Real Ale (CAMRA) was founded in 1971 to protect traditional—unpressurised—beer and brewing methods. The group devised the term real ale to differentiate between beer served from the cask and beer served under pressure. The term real ale has since been expanded to include bottle-conditioned beer.
Keg beer is often filtered and/or pasteurised, both of which are processes that render the yeast inactive.
In brewing parlance, a keg is different from a cask. A cask has a tap hole near the edge of the top, and a spile hole on the side used for conditioning the unfiltered and unpasteurised beer. A keg has a single opening in the centre of the top to which a flow pipe is attached. Kegs are artificially pressurised after fermentation with carbon dioxide or a mixture of carbon dioxide and nitrogen gas or especially in Czech Republic solely compressed air.
Keg has become a term of contempt used by some, particularly in the UK, since the 1960s when pasteurised draught beers started replacing traditional cask beers.
Keg beer was replacing traditional cask ale in all parts of the UK, primarily because it requires less care to handle. Since 1971, CAMRA has conducted a consumer campaign on behalf of those who prefer traditional cask beer. CAMRA has lobbied the British Parliament to ensure support for cask ale and microbreweries have sprung up to serve those consumers who prefer traditional cask beer.
Pressurised CO2 in the keg's headspace maintains carbonation in the beer. The CO2 pressure varies depending on the amount of CO2 already in the beer and the keg storage temperature. Occasionally the CO2 gas is blended with nitrogen gas. CO2 / nitrogen blends are used to allow a higher operating pressure in complex dispensing systems.
Nitrogen is used under high pressure when dispensing dry stouts (such as Guinness) and other creamy beers because it displaces CO2 to (artificially) form a rich tight head and a less carbonated taste. This makes the beer feel smooth on the palate and gives a foamy appearance. Premixed bottled gas for creamy beers is usually 75% nitrogen and 25% CO2. This premixed gas, which only works well with creamy beers, is often referred to as Guinness Gas, Beer Gas, or Aligal (an Air Liquide brand name). Using "Beer Gas" with other beer styles can cause the last 5% to 10% of the beer in each keg to taste very flat and lifeless. In the UK, the term keg beer would imply the beer is pasteurised, in contrast to unpasteurised cask ale. Some of the newer microbreweries may offer a nitro keg stout which is filtered but not pasteurised.
Cask beer should be stored and served at a cellar temperature of 12 °C (54 °F). Once a cask is opened, it should be consumed within three days. Keg beer is given additional cooling just prior to being served either by flash coolers or a remote cooler in the cellar. This chills the beer to temperatures between 3 and 8 °C (37 and 46 °F).
The words "draft" and "draught" have been used as marketing terms to describe canned or bottled beers, implying that they taste and appear like beers from a cask or keg. Commercial brewers use this as a marketing tool although it is incorrect to call any beer not drawn from a cask or keg "draught". Two examples are Miller Genuine Draft, a pale lager which is produced using a cold filtering system, and Guinness stout in patented "Draught-flow" cans and bottles. Guinness is an example of beers that use a nitrogen widget to create a smooth beer with a dense head. Guinness has recently replaced the widget system from their bottled "draught" beer with a coating of cellulose fibres on the inside of the bottle. Statements indicate a new development in bottling technology that enables the mixture of nitrogen and carbon dioxide to be present in the beer without using a widget, making it according to Guinness "more drinkable" from the bottle.
In East Asian countries, such as China and Japan, the term "draft beer" (Chinese: 生啤酒; Japanese: 生ビール) applied to canned or bottled beer indicates that the beer is not pasteurised (though it may be filtered), giving it a fresher taste but shorter shelf-life than conventional packaged beers. | [
{
"paragraph_id": 0,
"text": "Draught beer, also spelt draft, is beer served from a cask or keg rather than from a bottle or can. Draught beer served from a pressurised keg is also known as keg beer.",
"title": ""
},
{
"paragraph_id": 1,
"text": "Until Joseph Bramah patented the beer engine in 1785, beer was served directly from the barrel and carried to the customer. The Old English dragan (\"carry; pull\") developed into a series of related words including drag, draw, and draught. By the time Bramah's beer pumps became popular, the use of the term draught to refer to the acts of serving or drinking beer was well established and transferred easily to beer served via the hand pumps. In time, the word came to be restricted to only such beer. The usual spelling is now \"draught\" in the United Kingdom, Ireland, Australia, and New Zealand and more commonly \"draft\" in North America, although it can be spelt either way. Regardless of spelling, the word is pronounced /drɑːft/ or /dræft/ depending on the region the speaker is from.",
"title": "Name"
},
{
"paragraph_id": 2,
"text": "Canned draught is beer served from a pressurised container featuring a widget. Smooth flow (also known as cream flow, nitrokeg, or smooth) is the name brewers give to draught beers pressurised with a partial nitrogen gas blend.",
"title": "Name"
},
{
"paragraph_id": 3,
"text": "In 1691, an article in the London Gazette mentioned John Lofting, who held a patent for a fire engine: \"The said patentee has also projected a very useful engine for starting of beer, and other liquors which will draw from 20 to 30 barrels an hour, which are completely fixed with brass joints and screws at reasonable rates\".",
"title": "History"
},
{
"paragraph_id": 4,
"text": "In the early 20th century, draught beer started to be served from pressurised containers. Artificial carbonation was introduced in the United Kingdom in 1936, with Watney's experimental pasteurised beer Red Barrel. Though this method of serving beer did not take hold in the UK until the late 1950s, it did become the favored method in the rest of Europe, where it is known by such terms as en pression. The carbonation method of serving beer subsequently spread to the rest of the world; by the early 1970s the term \"draught beer\" almost exclusively referred to beer served under pressure as opposed to the traditional cask or barrel beer.",
"title": "History"
},
{
"paragraph_id": 5,
"text": "In Britain, the Campaign for Real Ale (CAMRA) was founded in 1971 to protect traditional—unpressurised—beer and brewing methods. The group devised the term real ale to differentiate between beer served from the cask and beer served under pressure. The term real ale has since been expanded to include bottle-conditioned beer.",
"title": "History"
},
{
"paragraph_id": 6,
"text": "Keg beer is often filtered and/or pasteurised, both of which are processes that render the yeast inactive.",
"title": "Keg beer"
},
{
"paragraph_id": 7,
"text": "In brewing parlance, a keg is different from a cask. A cask has a tap hole near the edge of the top, and a spile hole on the side used for conditioning the unfiltered and unpasteurised beer. A keg has a single opening in the centre of the top to which a flow pipe is attached. Kegs are artificially pressurised after fermentation with carbon dioxide or a mixture of carbon dioxide and nitrogen gas or especially in Czech Republic solely compressed air.",
"title": "Keg beer"
},
{
"paragraph_id": 8,
"text": "Keg has become a term of contempt used by some, particularly in the UK, since the 1960s when pasteurised draught beers started replacing traditional cask beers.",
"title": "Keg beer"
},
{
"paragraph_id": 9,
"text": "Keg beer was replacing traditional cask ale in all parts of the UK, primarily because it requires less care to handle. Since 1971, CAMRA has conducted a consumer campaign on behalf of those who prefer traditional cask beer. CAMRA has lobbied the British Parliament to ensure support for cask ale and microbreweries have sprung up to serve those consumers who prefer traditional cask beer.",
"title": "Keg beer"
},
{
"paragraph_id": 10,
"text": "Pressurised CO2 in the keg's headspace maintains carbonation in the beer. The CO2 pressure varies depending on the amount of CO2 already in the beer and the keg storage temperature. Occasionally the CO2 gas is blended with nitrogen gas. CO2 / nitrogen blends are used to allow a higher operating pressure in complex dispensing systems.",
"title": "Keg beer"
},
{
"paragraph_id": 11,
"text": "Nitrogen is used under high pressure when dispensing dry stouts (such as Guinness) and other creamy beers because it displaces CO2 to (artificially) form a rich tight head and a less carbonated taste. This makes the beer feel smooth on the palate and gives a foamy appearance. Premixed bottled gas for creamy beers is usually 75% nitrogen and 25% CO2. This premixed gas, which only works well with creamy beers, is often referred to as Guinness Gas, Beer Gas, or Aligal (an Air Liquide brand name). Using \"Beer Gas\" with other beer styles can cause the last 5% to 10% of the beer in each keg to taste very flat and lifeless. In the UK, the term keg beer would imply the beer is pasteurised, in contrast to unpasteurised cask ale. Some of the newer microbreweries may offer a nitro keg stout which is filtered but not pasteurised.",
"title": "Keg beer"
},
{
"paragraph_id": 12,
"text": "Cask beer should be stored and served at a cellar temperature of 12 °C (54 °F). Once a cask is opened, it should be consumed within three days. Keg beer is given additional cooling just prior to being served either by flash coolers or a remote cooler in the cellar. This chills the beer to temperatures between 3 and 8 °C (37 and 46 °F).",
"title": "Storage and serving temperature"
},
{
"paragraph_id": 13,
"text": "The words \"draft\" and \"draught\" have been used as marketing terms to describe canned or bottled beers, implying that they taste and appear like beers from a cask or keg. Commercial brewers use this as a marketing tool although it is incorrect to call any beer not drawn from a cask or keg \"draught\". Two examples are Miller Genuine Draft, a pale lager which is produced using a cold filtering system, and Guinness stout in patented \"Draught-flow\" cans and bottles. Guinness is an example of beers that use a nitrogen widget to create a smooth beer with a dense head. Guinness has recently replaced the widget system from their bottled \"draught\" beer with a coating of cellulose fibres on the inside of the bottle. Statements indicate a new development in bottling technology that enables the mixture of nitrogen and carbon dioxide to be present in the beer without using a widget, making it according to Guinness \"more drinkable\" from the bottle.",
"title": "Canned and bottled \"draught\""
},
{
"paragraph_id": 14,
"text": "In East Asian countries, such as China and Japan, the term \"draft beer\" (Chinese: 生啤酒; Japanese: 生ビール) applied to canned or bottled beer indicates that the beer is not pasteurised (though it may be filtered), giving it a fresher taste but shorter shelf-life than conventional packaged beers.",
"title": "Canned and bottled \"draught\""
}
] | Draught beer, also spelt draft, is beer served from a cask or keg rather than from a bottle or can. Draught beer served from a pressurised keg is also known as keg beer. | 2002-02-03T18:58:53Z | 2023-09-28T05:54:07Z | [
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8,388 | Director | Director may refer to: | [
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8,389 | Major depressive disorder | Major depressive disorder (MDD), also known as clinical depression, is a mental disorder characterized by at least two weeks of pervasive low mood, low self-esteem, and loss of interest or pleasure in normally enjoyable activities. Introduced by a group of US clinicians in the mid-1970s, the term was adopted by the American Psychiatric Association for this symptom cluster under mood disorders in the 1980 version of the Diagnostic and Statistical Manual of Mental Disorders (DSM-III), and has become widely used since.
The diagnosis of major depressive disorder is based on the person's reported experiences, behavior reported by relatives or friends, and a mental status examination. There is no laboratory test for the disorder, but testing may be done to rule out physical conditions that can cause similar symptoms. The most common time of onset is in a person's 20s, with females affected about twice as often as males. The course of the disorder varies widely, from one episode lasting months to a lifelong disorder with recurrent major depressive episodes.
Those with major depressive disorder are typically treated with psychotherapy and antidepressant medication. Medication appears to be effective, but the effect may be significant only in the most severely depressed. Hospitalization (which may be involuntary) may be necessary in cases with associated self-neglect or a significant risk of harm to self or others. Electroconvulsive therapy (ECT) may be considered if other measures are not effective.
Major depressive disorder is believed to be caused by a combination of genetic, environmental, and psychological factors, with about 40% of the risk being genetic. Risk factors include a family history of the condition, major life changes, certain medications, chronic health problems, and substance use disorders. It can negatively affect a person's personal life, work life, or education, and cause issues with a person's sleeping habits, eating habits, and general health. Major depressive disorder affected approximately 163 million people (2% of the world's population) in 2017. The percentage of people who are affected at one point in their life varies from 7% in Japan to 21% in France. Lifetime rates are higher in the developed world (15%) compared to the developing world (11%). The disorder causes the second-most years lived with disability, after lower back pain.
Major depression significantly affects a person's family and personal relationships, work or school life, sleeping and eating habits, and general health. A person having a major depressive episode usually exhibits a low mood, which pervades all aspects of life, and an inability to experience pleasure in previously enjoyable activities. Depressed people may be preoccupied with—or ruminate over—thoughts and feelings of worthlessness, inappropriate guilt or regret, helplessness or hopelessness.
Other symptoms of depression include poor concentration and memory, withdrawal from social situations and activities, reduced sex drive, irritability, and thoughts of death or suicide. Insomnia is common; in the typical pattern, a person wakes very early and cannot get back to sleep. Hypersomnia, or oversleeping, can also happen, as well as day-night rhythm disturbances, such as diurnal mood variation. Some antidepressants may also cause insomnia due to their stimulating effect. In severe cases, depressed people may have psychotic symptoms. These symptoms include delusions or, less commonly, hallucinations, usually unpleasant. People who have had previous episodes with psychotic symptoms are more likely to have them with future episodes.
A depressed person may report multiple physical symptoms such as fatigue, headaches, or digestive problems; physical complaints are the most common presenting problem in developing countries, according to the World Health Organization's criteria for depression. Appetite often decreases, resulting in weight loss, although increased appetite and weight gain occasionally occur. Family and friends may notice agitation or lethargy. Older depressed people may have cognitive symptoms of recent onset, such as forgetfulness, and a more noticeable slowing of movements.
Depressed children may often display an irritable rather than a depressed mood; most lose interest in school and show a steep decline in academic performance. Diagnosis may be delayed or missed when symptoms are interpreted as "normal moodiness." Elderly people may not present with classical depressive symptoms. Diagnosis and treatment is further complicated in that the elderly are often simultaneously treated with a number of other drugs, and often have other concurrent diseases.
The etiology of depression is not yet fully understood. The biopsychosocial model proposes that biological, psychological, and social factors all play a role in causing depression. The diathesis–stress model specifies that depression results when a preexisting vulnerability, or diathesis, is activated by stressful life events. The preexisting vulnerability can be either genetic, implying an interaction between nature and nurture, or schematic, resulting from views of the world learned in childhood. American psychiatrist Aaron Beck suggested that a triad of automatic and spontaneous negative thoughts about the self, the world or environment, and the future may lead to other depressive signs and symptoms.
Genes play a major role in the development of depression. Family and twin studies find that nearly 40% of individual differences in risk for major depressive disorder can be explained by genetic factors. Like most psychiatric disorders, major depressive disorder is likely influenced by many individual genetic changes. In 2018, a genome-wide association study discovered 44 genetic variants linked to risk for major depression; a 2019 study found 102 variants in the genome linked to depression. However, it appears that major depression is less heritable compared to bipolar disorder and schizophrenia. Research focusing on specific candidate genes has been criticized for its tendency to generate false positive findings. There are also other efforts to examine interactions between life stress and polygenic risk for depression.
Depression can also arise after a chronic or terminal medical condition, such as HIV/AIDS or asthma, and may be labeled "secondary depression." It is unknown whether the underlying diseases induce depression through effect on quality of life, or through shared etiologies (such as degeneration of the basal ganglia in Parkinson's disease or immune dysregulation in asthma). Depression may also be iatrogenic (the result of healthcare), such as drug-induced depression. Therapies associated with depression include interferons, beta-blockers, isotretinoin, contraceptives, cardiac agents, anticonvulsants, antimigraine drugs, antipsychotics, and hormonal agents such as gonadotropin-releasing hormone agonist (GnRH agonist).
Substance use in early age is associated with increased risk of developing depression later in life. Depression occurring after giving birth is called postpartum depression and is thought to be the result of hormonal changes associated with pregnancy. Seasonal affective disorder, a type of depression associated with seasonal changes in sunlight, is thought to be triggered by decreased sunlight. Vitamin B2, B6 and B12 deficiency may cause depression in females.
Adverse childhood experiences (incorporating childhood abuse, neglect and family dysfunction) markedly increase the risk of major depression, especially if more than one type. Childhood trauma also correlates with severity of depression, poor responsiveness to treatment and length of illness. Some are more susceptible than others to developing mental illness such as depression after trauma, and various genes have been suggested to control susceptibility. Couples in unhappy marriages have a higher risk of developing clinical depression.
There appears to be a link between air pollution and depression and suicide. There may be an association between long-term PM2.5 exposure and depression, and a possible association between short-term PM10 exposure and suicide.
The pathophysiology of depression is not completely understood, but current theories center around monoaminergic systems, the circadian rhythm, immunological dysfunction, HPA-axis dysfunction and structural or functional abnormalities of emotional circuits.
Derived from the effectiveness of monoaminergic drugs in treating depression, the monoamine theory posits that insufficient activity of monoamine neurotransmitters is the primary cause of depression. Evidence for the monoamine theory comes from multiple areas. First, acute depletion of tryptophan—a necessary precursor of serotonin and a monoamine—can cause depression in those in remission or relatives of people who are depressed, suggesting that decreased serotonergic neurotransmission is important in depression. Second, the correlation between depression risk and polymorphisms in the 5-HTTLPR gene, which codes for serotonin receptors, suggests a link. Third, decreased size of the locus coeruleus, decreased activity of tyrosine hydroxylase, increased density of alpha-2 adrenergic receptor, and evidence from rat models suggest decreased adrenergic neurotransmission in depression. Furthermore, decreased levels of homovanillic acid, altered response to dextroamphetamine, responses of depressive symptoms to dopamine receptor agonists, decreased dopamine receptor D1 binding in the striatum, and polymorphism of dopamine receptor genes implicate dopamine, another monoamine, in depression. Lastly, increased activity of monoamine oxidase, which degrades monoamines, has been associated with depression. However, the monoamine theory is inconsistent with observations that serotonin depletion does not cause depression in healthy persons, that antidepressants instantly increase levels of monoamines but take weeks to work, and the existence of atypical antidepressants which can be effective despite not targeting this pathway.
One proposed explanation for the therapeutic lag, and further support for the deficiency of monoamines, is a desensitization of self-inhibition in raphe nuclei by the increased serotonin mediated by antidepressants. However, disinhibition of the dorsal raphe has been proposed to occur as a result of decreased serotonergic activity in tryptophan depletion, resulting in a depressed state mediated by increased serotonin. Further countering the monoamine hypothesis is the fact that rats with lesions of the dorsal raphe are not more depressive than controls, the finding of increased jugular 5-HIAA in people who are depressed that normalized with selective serotonin reuptake inhibitor (SSRI) treatment, and the preference for carbohydrates in people who are depressed. Already limited, the monoamine hypothesis has been further oversimplified when presented to the general public. A 2022 review found no consistent evidence supporting the serotonin hypothesis, linking serotonin levels and depression.
Immune system abnormalities have been observed, including increased levels of cytokines involved in generating sickness behavior (which shares overlap with depression). The effectiveness of nonsteroidal anti-inflammatory drugs (NSAIDs) and cytokine inhibitors in treating depression, and normalization of cytokine levels after successful treatment further suggest immune system abnormalities in depression.
HPA-axis abnormalities have been suggested in depression given the association of CRHR1 with depression and the increased frequency of dexamethasone test non-suppression in people who are depressed. However, this abnormality is not adequate as a diagnosis tool, because its sensitivity is only 44%. These stress-related abnormalities are thought to be the cause of hippocampal volume reductions seen in people who are depressed. Furthermore, a meta-analysis yielded decreased dexamethasone suppression, and increased response to psychological stressors. Further abnormal results have been obscured with the cortisol awakening response, with increased response being associated with depression.
Theories unifying neuroimaging findings have been proposed. The first model proposed is the limbic-cortical model, which involves hyperactivity of the ventral paralimbic regions and hypoactivity of frontal regulatory regions in emotional processing. Another model, the cortico-striatal model, suggests that abnormalities of the prefrontal cortex in regulating striatal and subcortical structures result in depression. Another model proposes hyperactivity of salience structures in identifying negative stimuli, and hypoactivity of cortical regulatory structures resulting in a negative emotional bias and depression, consistent with emotional bias studies.
A diagnostic assessment may be conducted by a suitably trained general practitioner, or by a psychiatrist or psychologist, who records the person's current circumstances, biographical history, current symptoms, family history, and alcohol and drug use. The assessment also includes a mental state examination, which is an assessment of the person's current mood and thought content, in particular the presence of themes of hopelessness or pessimism, self-harm or suicide, and an absence of positive thoughts or plans. Specialist mental health services are rare in rural areas, and thus diagnosis and management is left largely to primary-care clinicians. This issue is even more marked in developing countries. Rating scales are not used to diagnose depression, but they provide an indication of the severity of symptoms for a time period, so a person who scores above a given cut-off point can be more thoroughly evaluated for a depressive disorder diagnosis. Several rating scales are used for this purpose; these include the Hamilton Rating Scale for Depression, the Beck Depression Inventory or the Suicide Behaviors Questionnaire-Revised.
Primary-care physicians have more difficulty with underrecognition and undertreatment of depression compared to psychiatrists. These cases may be missed because for some people with depression, physical symptoms often accompany depression. In addition, there may also be barriers related to the person, provider, and/or the medical system. Non-psychiatrist physicians have been shown to miss about two-thirds of cases, although there is some evidence of improvement in the number of missed cases.
A doctor generally performs a medical examination and selected investigations to rule out other causes of depressive symptoms. These include blood tests measuring TSH and thyroxine to exclude hypothyroidism; basic electrolytes and serum calcium to rule out a metabolic disturbance; and a full blood count including ESR to rule out a systemic infection or chronic disease. Adverse affective reactions to medications or alcohol misuse may be ruled out, as well. Testosterone levels may be evaluated to diagnose hypogonadism, a cause of depression in men. Vitamin D levels might be evaluated, as low levels of vitamin D have been associated with greater risk for depression. Subjective cognitive complaints appear in older depressed people, but they can also be indicative of the onset of a dementing disorder, such as Alzheimer's disease. Cognitive testing and brain imaging can help distinguish depression from dementia. A CT scan can exclude brain pathology in those with psychotic, rapid-onset or otherwise unusual symptoms. No biological tests confirm major depression. In general, investigations are not repeated for a subsequent episode unless there is a medical indication.
The most widely used criteria for diagnosing depressive conditions are found in the American Psychiatric Association's Diagnostic and Statistical Manual of Mental Disorders (DSM) and the World Health Organization's International Statistical Classification of Diseases and Related Health Problems (ICD). The latter system is typically used in European countries, while the former is used in the US and many other non-European nations, and the authors of both have worked towards conforming one with the other. Both DSM and ICD mark out typical (main) depressive symptoms. The most recent edition of the DSM is the Fifth Edition, Text Revision (DSM-5-TR), and the most recent edition of the ICD is the Eleventh Edition (ICD-11).
Under mood disorders, ICD-11 classifies major depressive disorder as either single episode depressive disorder (where there is no history of depressive episodes, or of mania) or recurrent depressive disorder (where there is a history of prior episodes, with no history of mania). ICD-11 symptoms, present nearly every day for at least two weeks, are a depressed mood or anhedonia, accompanied by other symptoms such as "difficulty concentrating, feelings of worthlessness or excessive or inappropriate guilt, hopelessness, recurrent thoughts of death or suicide, changes in appetite or sleep, psychomotor agitation or retardation, and reduced energy or fatigue." These symptoms must affect work, social, or domestic activities. The ICD-11 system allows further specifiers for the current depressive episode: the severity (mild, moderate, severe, unspecified); the presence of psychotic symptoms (with or without psychotic symptoms); and the degree of remission if relevant (currently in partial remission, currently in full remission). These two disorders are classified as "Depressive disorders", in the category of "Mood disorders".
According to DSM-5, there are two main depressive symptoms: a depressed mood, and loss of interest/pleasure in activities (anhedonia). These symptoms, as well as five out of the nine more specific symptoms listed, must frequently occur for more than two weeks (to the extent in which it impairs functioning) for the diagnosis. Major depressive disorder is classified as a mood disorder in the DSM-5. The diagnosis hinges on the presence of single or recurrent major depressive episodes. Further qualifiers are used to classify both the episode itself and the course of the disorder. The category Unspecified Depressive Disorder is diagnosed if the depressive episode's manifestation does not meet the criteria for a major depressive episode.
A major depressive episode is characterized by the presence of a severely depressed mood that persists for at least two weeks. Episodes may be isolated or recurrent and are categorized as mild (few symptoms in excess of minimum criteria), moderate, or severe (marked impact on social or occupational functioning). An episode with psychotic features—commonly referred to as psychotic depression—is automatically rated as severe. If the person has had an episode of mania or markedly elevated mood, a diagnosis of bipolar disorder is made instead. Depression without mania is sometimes referred to as unipolar because the mood remains at one emotional state or "pole".
Bereavement is not an exclusion criterion in the DSM-5, and it is up to the clinician to distinguish between normal reactions to a loss and MDD. Excluded are a range of related diagnoses, including dysthymia, which involves a chronic but milder mood disturbance; recurrent brief depression, consisting of briefer depressive episodes; minor depressive disorder, whereby only some symptoms of major depression are present; and adjustment disorder with depressed mood, which denotes low mood resulting from a psychological response to an identifiable event or stressor.
The DSM-5 recognizes six further subtypes of MDD, called specifiers, in addition to noting the length, severity and presence of psychotic features:
To confirm major depressive disorder as the most likely diagnosis, other potential diagnoses must be considered, including dysthymia, adjustment disorder with depressed mood, or bipolar disorder. Dysthymia is a chronic, milder mood disturbance in which a person reports a low mood almost daily over a span of at least two years. The symptoms are not as severe as those for major depression, although people with dysthymia are vulnerable to secondary episodes of major depression (sometimes referred to as double depression). Adjustment disorder with depressed mood is a mood disturbance appearing as a psychological response to an identifiable event or stressor, in which the resulting emotional or behavioral symptoms are significant but do not meet the criteria for a major depressive episode.
Other disorders need to be ruled out before diagnosing major depressive disorder. They include depressions due to physical illness, medications, and substance use disorders. Depression due to physical illness is diagnosed as a mood disorder due to a general medical condition. This condition is determined based on history, laboratory findings, or physical examination. When the depression is caused by a medication, non-medical use of a psychoactive substance, or exposure to a toxin, it is then diagnosed as a specific mood disorder (previously called substance-induced mood disorder).
Preventive efforts may result in decreases in rates of the condition of between 22 and 38%. Since 2016, the United States Preventive Services Task Force (USPSTF) has recommended screening for depression among those over the age 12; though a 2005 Cochrane review found that the routine use of screening questionnaires has little effect on detection or treatment. Screening the general population is not recommended by authorities in the UK or Canada.
Behavioral interventions, such as interpersonal therapy and cognitive-behavioral therapy, are effective at preventing new onset depression. Because such interventions appear to be most effective when delivered to individuals or small groups, it has been suggested that they may be able to reach their large target audience most efficiently through the Internet.
The Netherlands mental health care system provides preventive interventions, such as the "Coping with Depression" course (CWD) for people with sub-threshold depression. The course is claimed to be the most successful of psychoeducational interventions for the treatment and prevention of depression (both for its adaptability to various populations and its results), with a risk reduction of 38% in major depression and an efficacy as a treatment comparing favorably to other psychotherapies.
The most common and effective treatments for depression are psychotherapy, medication, and electroconvulsive therapy (ECT); a combination of treatments is the most effective approach when depression is resistant to treatment. American Psychiatric Association treatment guidelines recommend that initial treatment should be individually tailored based on factors including severity of symptoms, co-existing disorders, prior treatment experience, and personal preference. Options may include pharmacotherapy, psychotherapy, exercise, ECT, transcranial magnetic stimulation (TMS) or light therapy. Antidepressant medication is recommended as an initial treatment choice in people with mild, moderate, or severe major depression, and should be given to all people with severe depression unless ECT is planned. There is evidence that collaborative care by a team of health care practitioners produces better results than routine single-practitioner care.
Psychotherapy is the treatment of choice (over medication) for people under 18, and cognitive behavioral therapy (CBT), third wave CBT and interpersonal therapy may help prevent depression. The UK National Institute for Health and Care Excellence (NICE) 2004 guidelines indicate that antidepressants should not be used for the initial treatment of mild depression because the risk-benefit ratio is poor. The guidelines recommend that antidepressants treatment in combination with psychosocial interventions should be considered for:
The guidelines further note that antidepressant treatment should be continued for at least six months to reduce the risk of relapse, and that SSRIs are better tolerated than tricyclic antidepressants.
Treatment options are more limited in developing countries, where access to mental health staff, medication, and psychotherapy is often difficult. Development of mental health services is minimal in many countries; depression is viewed as a phenomenon of the developed world despite evidence to the contrary, and not as an inherently life-threatening condition. There is insufficient evidence to determine the effectiveness of psychological versus medical therapy in children.
Physical exercise has been found to be effective for major depression, and may be recommended to people who are willing, motivated, and healthy enough to participate in an exercise program as treatment. It is equivalent to the use of medications or psychological therapies in most people. In older people it does appear to decrease depression. Sleep and diet may also play a role in depression, and interventions in these areas may be an effective add-on to conventional methods. In observational studies, smoking cessation has benefits in depression as large as or larger than those of medications.
Talking therapy (psychotherapy) can be delivered to individuals, groups, or families by mental health professionals, including psychotherapists, psychiatrists, psychologists, clinical social workers, counselors, and psychiatric nurses. A 2012 review found psychotherapy to be better than no treatment but not other treatments. With more complex and chronic forms of depression, a combination of medication and psychotherapy may be used. There is moderate-quality evidence that psychological therapies are a useful addition to standard antidepressant treatment of treatment-resistant depression in the short term. Psychotherapy has been shown to be effective in older people. Successful psychotherapy appears to reduce the recurrence of depression even after it has been stopped or replaced by occasional booster sessions.
The most-studied form of psychotherapy for depression is CBT, which teaches clients to challenge self-defeating, but enduring ways of thinking (cognitions) and change counter-productive behaviors. CBT can perform as well as antidepressants in people with major depression. CBT has the most research evidence for the treatment of depression in children and adolescents, and CBT and interpersonal psychotherapy (IPT) are preferred therapies for adolescent depression. In people under 18, according to the National Institute for Health and Clinical Excellence, medication should be offered only in conjunction with a psychological therapy, such as CBT, interpersonal therapy, or family therapy. Several variables predict success for cognitive behavioral therapy in adolescents: higher levels of rational thoughts, less hopelessness, fewer negative thoughts, and fewer cognitive distortions. CBT is particularly beneficial in preventing relapse. Cognitive behavioral therapy and occupational programs (including modification of work activities and assistance) have been shown to be effective in reducing sick days taken by workers with depression. Several variants of cognitive behavior therapy have been used in those with depression, the most notable being rational emotive behavior therapy, and mindfulness-based cognitive therapy. Mindfulness-based stress reduction programs may reduce depression symptoms. Mindfulness programs also appear to be a promising intervention in youth. Problem solving therapy, cognitive behavioral therapy, and interpersonal therapy are effective interventions in the elderly.
Psychoanalysis is a school of thought, founded by Sigmund Freud, which emphasizes the resolution of unconscious mental conflicts. Psychoanalytic techniques are used by some practitioners to treat clients presenting with major depression. A more widely practiced therapy, called psychodynamic psychotherapy, is in the tradition of psychoanalysis but less intensive, meeting once or twice a week. It also tends to focus more on the person's immediate problems, and has an additional social and interpersonal focus. In a meta-analysis of three controlled trials of Short Psychodynamic Supportive Psychotherapy, this modification was found to be as effective as medication for mild to moderate depression.
Conflicting results have arisen from studies that look at the effectiveness of antidepressants in people with acute, mild to moderate depression. A review commissioned by the National Institute for Health and Care Excellence (UK) concluded that there is strong evidence that SSRIs, such as escitalopram, paroxetine, and sertraline, have greater efficacy than placebo on achieving a 50% reduction in depression scores in moderate and severe major depression, and that there is some evidence for a similar effect in mild depression. Similarly, a Cochrane systematic review of clinical trials of the generic tricyclic antidepressant amitriptyline concluded that there is strong evidence that its efficacy is superior to placebo. Antidepressants work less well for the elderly than for younger individuals with depression.
To find the most effective antidepressant medication with minimal side-effects, the dosages can be adjusted, and if necessary, combinations of different classes of antidepressants can be tried. Response rates to the first antidepressant administered range from 50 to 75%, and it can take at least six to eight weeks from the start of medication to improvement. Antidepressant medication treatment is usually continued for 16 to 20 weeks after remission, to minimize the chance of recurrence, and even up to one year of continuation is recommended. People with chronic depression may need to take medication indefinitely to avoid relapse.
SSRIs are the primary medications prescribed, owing to their relatively mild side-effects, and because they are less toxic in overdose than other antidepressants. People who do not respond to one SSRI can be switched to another antidepressant, and this results in improvement in almost 50% of cases. Another option is to switch to the atypical antidepressant bupropion. Venlafaxine, an antidepressant with a different mechanism of action, may be modestly more effective than SSRIs. However, venlafaxine is not recommended in the UK as a first-line treatment because of evidence suggesting its risks may outweigh benefits, and it is specifically discouraged in children and adolescents as it increases the risk of suicidal thoughts or attempts.
For children and adolescents with moderate-to-severe depressive disorder, fluoxetine seems to be the best treatment (either with or without cognitive behavioural therapy) but more research is needed to be certain. Sertraline, escitalopram, duloxetine might also help in reducing symptoms. Some antidepressants have not been shown to be effective. Medications are not recommended in children with mild disease.
There is also insufficient evidence to determine effectiveness in those with depression complicated by dementia. Any antidepressant can cause low blood sodium levels; nevertheless, it has been reported more often with SSRIs. It is not uncommon for SSRIs to cause or worsen insomnia; the sedating atypical antidepressant mirtazapine can be used in such cases.
Irreversible monoamine oxidase inhibitors, an older class of antidepressants, have been plagued by potentially life-threatening dietary and drug interactions. They are still used only rarely, although newer and better-tolerated agents of this class have been developed. The safety profile is different with reversible monoamine oxidase inhibitors, such as moclobemide, where the risk of serious dietary interactions is negligible and dietary restrictions are less strict.
It is unclear whether antidepressants affect a person's risk of suicide. For children, adolescents, and probably young adults between 18 and 24 years old, there is a higher risk of both suicidal ideations and suicidal behavior in those treated with SSRIs. For adults, it is unclear whether SSRIs affect the risk of suicidality. One review found no connection; another an increased risk; and a third no risk in those 25–65 years old and a decreased risk in those more than 65. A black box warning was introduced in the United States in 2007 on SSRIs and other antidepressant medications due to the increased risk of suicide in people younger than 24 years old. Similar precautionary notice revisions were implemented by the Japanese Ministry of Health.
The combined use of antidepressants plus benzodiazepines demonstrates improved effectiveness when compared to antidepressants alone, but these effects may not endure. The addition of a benzodiazepine is balanced against possible harms and other alternative treatment strategies when antidepressant mono-therapy is considered inadequate.
For treatment-resistant depression, adding on the atypical antipsychotic brexpiprazole for short-term or acute management may be considered. Brexpiprazole may be effective for some people, however, the evidence as of 2023 supporting its use is weak and this medication has potential adverse effects including weight gain and akathisia. Brexpiprazole has not been sufficiently studied in older people or children and the use and effectiveness of this adjunctive therapy for longer term management is not clear.
Ketamine may have a rapid antidepressant effect lasting less than two weeks; there is limited evidence of any effect after that, common acute side effects, and longer-term studies of safety and adverse effects are needed. A nasal spray form of esketamine was approved by the FDA in March 2019 for use in treatment-resistant depression when combined with an oral antidepressant; risk of substance use disorder and concerns about its safety, serious adverse effects, tolerability, effect on suicidality, lack of information about dosage, whether the studies on it adequately represent broad populations, and escalating use of the product have been raised by an international panel of experts.
There is insufficient high quality evidence to suggest omega-3 fatty acids are effective in depression. There is limited evidence that vitamin D supplementation is of value in alleviating the symptoms of depression in individuals who are vitamin D-deficient. Lithium appears effective at lowering the risk of suicide in those with bipolar disorder and unipolar depression to nearly the same levels as the general population. There is a narrow range of effective and safe dosages of lithium thus close monitoring may be needed. Low-dose thyroid hormone may be added to existing antidepressants to treat persistent depression symptoms in people who have tried multiple courses of medication. Limited evidence suggests stimulants, such as amphetamine and modafinil, may be effective in the short term, or as adjuvant therapy. Also, it is suggested that folate supplements may have a role in depression management. There is tentative evidence for benefit from testosterone in males.
Electroconvulsive therapy (ECT) is a standard psychiatric treatment in which seizures are electrically induced in a person with depression to provide relief from psychiatric illnesses. ECT is used with informed consent as a last line of intervention for major depressive disorder. A round of ECT is effective for about 50% of people with treatment-resistant major depressive disorder, whether it is unipolar or bipolar. Follow-up treatment is still poorly studied, but about half of people who respond relapse within twelve months. Aside from effects in the brain, the general physical risks of ECT are similar to those of brief general anesthesia. Immediately following treatment, the most common adverse effects are confusion and memory loss. ECT is considered one of the least harmful treatment options available for severely depressed pregnant women.
A usual course of ECT involves multiple administrations, typically given two or three times per week, until the person no longer has symptoms. ECT is administered under anesthesia with a muscle relaxant. Electroconvulsive therapy can differ in its application in three ways: electrode placement, frequency of treatments, and the electrical waveform of the stimulus. These three forms of application have significant differences in both adverse side effects and symptom remission. After treatment, drug therapy is usually continued, and some people receive maintenance ECT.
ECT appears to work in the short term via an anticonvulsant effect mostly in the frontal lobes, and longer term via neurotrophic effects primarily in the medial temporal lobe.
Transcranial magnetic stimulation (TMS) or deep transcranial magnetic stimulation is a noninvasive method used to stimulate small regions of the brain. TMS was approved by the FDA for treatment-resistant major depressive disorder (trMDD) in 2008 and as of 2014 evidence supports that it is probably effective. The American Psychiatric Association, the Canadian Network for Mood and Anxiety Disorders, and the Royal Australia and New Zealand College of Psychiatrists have endorsed TMS for trMDD. Transcranial direct current stimulation (tDCS) is another noninvasive method used to stimulate small regions of the brain with a weak electric current. Several meta-analyses have concluded that active tDCS was useful for treating depression.
There is a small amount of evidence that sleep deprivation may improve depressive symptoms in some individuals, with the effects usually showing up within a day. This effect is usually temporary. Besides sleepiness, this method can cause a side effect of mania or hypomania. There is insufficient evidence for Reiki and dance movement therapy in depression. Cannabis is specifically not recommended as a treatment.
Studies have shown that 80% of those with a first major depressive episode will have at least one more during their life, with a lifetime average of four episodes. Other general population studies indicate that around half those who have an episode recover (whether treated or not) and remain well, while the other half will have at least one more, and around 15% of those experience chronic recurrence. Studies recruiting from selective inpatient sources suggest lower recovery and higher chronicity, while studies of mostly outpatients show that nearly all recover, with a median episode duration of 11 months. Around 90% of those with severe or psychotic depression, most of whom also meet criteria for other mental disorders, experience recurrence. Cases when outcome is poor are associated with inappropriate treatment, severe initial symptoms including psychosis, early age of onset, previous episodes, incomplete recovery after one year of treatment, pre-existing severe mental or medical disorder, and family dysfunction.
A high proportion of people who experience full symptomatic remission still have at least one not fully resolved symptom after treatment. Recurrence or chronicity is more likely if symptoms have not fully resolved with treatment. Current guidelines recommend continuing antidepressants for four to six months after remission to prevent relapse. Evidence from many randomized controlled trials indicates continuing antidepressant medications after recovery can reduce the chance of relapse by 70% (41% on placebo vs. 18% on antidepressant). The preventive effect probably lasts for at least the first 36 months of use.
Major depressive episodes often resolve over time, whether or not they are treated. Outpatients on a waiting list show a 10–15% reduction in symptoms within a few months, with approximately 20% no longer meeting the full criteria for a depressive disorder. The median duration of an episode has been estimated to be 23 weeks, with the highest rate of recovery in the first three months. According to a 2013 review, 23% of untreated adults with mild to moderate depression will remit within 3 months, 32% within 6 months and 53% within 12 months.
Depression may affect people's ability to work. The combination of usual clinical care and support with return to work (like working less hours or changing tasks) probably reduces sick leave by 15%, and leads to fewer depressive symptoms and improved work capacity, reducing sick leave by an annual average of 25 days per year. Helping depressed people return to work without a connection to clinical care has not been shown to have an effect on sick leave days. Additional psychological interventions (such as online cognitive behavioral therapy) lead to fewer sick days compared to standard management only. Streamlining care or adding specific providers for depression care may help to reduce sick leave.
Depressed individuals have a shorter life expectancy than those without depression, in part because people who are depressed are at risk of dying of suicide. About 50% of people who die of suicide have a mood disorder such as major depression, and the risk is especially high if a person has a marked sense of hopelessness or has both depression and borderline personality disorder. About 2–8% of adults with major depression die by suicide. In the US, the lifetime risk of suicide associated with a diagnosis of major depression is estimated at 7% for men and 1% for women, even though suicide attempts are more frequent in women.
Depressed people have a higher rate of dying from other causes. There is a 1.5- to 2-fold increased risk of cardiovascular disease, independent of other known risk factors, and is itself linked directly or indirectly to risk factors such as smoking and obesity. People with major depression are less likely to follow medical recommendations for treating and preventing cardiovascular disorders, further increasing their risk of medical complications. Cardiologists may not recognize underlying depression that complicates a cardiovascular problem under their care.
Major depressive disorder affected approximately 163 million people in 2017 (2% of the global population). The percentage of people who are affected at one point in their life varies from 7% in Japan to 21% in France. In most countries the number of people who have depression during their lives falls within an 8–18% range.
In the United States, 8.4% of adults (21 million individuals) have at least one episode within a year-long period; the probability of having a major depressive episode is higher for females than males (10.5% to 6.2%), and highest for those aged 18 to 25 (17%). Among adolescents between the ages of 12 and 17, 17% of the U.S. population (4.1 million individuals) had a major depressive episode in 2020 (females 25.2%, males 9.2%). Among individuals reporting two or more races, the US prevalence is highest.
Major depression is about twice as common in women as in men, although it is unclear why this is so, and whether factors unaccounted for are contributing to this. The relative increase in occurrence is related to pubertal development rather than chronological age, reaches adult ratios between the ages of 15 and 18, and appears associated with psychosocial more than hormonal factors. In 2019, major depressive disorder was identified (using either the DSM-IV-TR or ICD-10) in the Global Burden of Disease Study as the fifth most common cause of years lived with disability and the 18th most common for disability-adjusted life years.
People are most likely to develop their first depressive episode between the ages of 30 and 40, and there is a second, smaller peak of incidence between ages 50 and 60. The risk of major depression is increased with neurological conditions such as stroke, Parkinson's disease, or multiple sclerosis, and during the first year after childbirth. It is also more common after cardiovascular illnesses, and is related more to those with a poor cardiac disease outcome than to a better one. Depressive disorders are more common in urban populations than in rural ones and the prevalence is increased in groups with poorer socioeconomic factors, e.g., homelessness. Depression is common among those over 65 years of age and increases in frequency beyond this age. The risk of depression increases in relation to the frailty of the individual. Depression is one of the most important factors which negatively impact quality of life in adults, as well as the elderly. Both symptoms and treatment among the elderly differ from those of the rest of the population.
Major depression was the leading cause of disease burden in North America and other high-income countries, and the fourth-leading cause worldwide as of 2006. In the year 2030, it is predicted to be the second-leading cause of disease burden worldwide after HIV, according to the WHO. Delay or failure in seeking treatment after relapse and the failure of health professionals to provide treatment are two barriers to reducing disability.
Major depression frequently co-occurs with other psychiatric problems. The 1990–92 National Comorbidity Survey (US) reported that half of those with major depression also have lifetime anxiety and its associated disorders, such as generalized anxiety disorder. Anxiety symptoms can have a major impact on the course of a depressive illness, with delayed recovery, increased risk of relapse, greater disability and increased suicidal behavior. Depressed people have increased rates of alcohol and substance use, particularly dependence, and around a third of individuals diagnosed with attention deficit hyperactivity disorder (ADHD) develop comorbid depression. Post-traumatic stress disorder and depression often co-occur. Depression may also coexist with ADHD, complicating the diagnosis and treatment of both. Depression is also frequently comorbid with alcohol use disorder and personality disorders. Depression can also be exacerbated during particular months (usually winter) in those with seasonal affective disorder. While overuse of digital media has been associated with depressive symptoms, using digital media may also improve mood in some situations.
Depression and pain often co-occur. One or more pain symptoms are present in 65% of people who have depression, and anywhere from 5 to 85% of people who are experiencing pain will also have depression, depending on the setting—a lower prevalence in general practice, and higher in specialty clinics. Depression is often underrecognized, and therefore undertreated, in patients presenting with pain. Depression often coexists with physical disorders common among the elderly, such as stroke, other cardiovascular diseases, Parkinson's disease, and chronic obstructive pulmonary disease.
The Ancient Greek physician Hippocrates described a syndrome of melancholia (μελαγχολία, melankholía) as a distinct disease with particular mental and physical symptoms; he characterized all "fears and despondencies, if they last a long time" as being symptomatic of the ailment. It was a similar but far broader concept than today's depression; prominence was given to a clustering of the symptoms of sadness, dejection, and despondency, and often fear, anger, delusions and obsessions were included.
The term depression itself was derived from the Latin verb deprimere, meaning "to press down". From the 14th century, "to depress" meant to subjugate or to bring down in spirits. It was used in 1665 in English author Richard Baker's Chronicle to refer to someone having "a great depression of spirit", and by English author Samuel Johnson in a similar sense in 1753. The term also came into use in physiology and economics. An early usage referring to a psychiatric symptom was by French psychiatrist Louis Delasiauve in 1856, and by the 1860s it was appearing in medical dictionaries to refer to a physiological and metaphorical lowering of emotional function. Since Aristotle, melancholia had been associated with men of learning and intellectual brilliance, a hazard of contemplation and creativity. However, by the 19th century, this association has largely shifted and melancholia became more commonly linked with women.
Although melancholia remained the dominant diagnostic term, depression gained increasing currency in medical treatises and was a synonym by the end of the century; German psychiatrist Emil Kraepelin may have been the first to use it as the overarching term, referring to different kinds of melancholia as depressive states. Freud likened the state of melancholia to mourning in his 1917 paper Mourning and Melancholia. He theorized that objective loss, such as the loss of a valued relationship through death or a romantic break-up, results in subjective loss as well; the depressed individual has identified with the object of affection through an unconscious, narcissistic process called the libidinal cathexis of the ego. Such loss results in severe melancholic symptoms more profound than mourning; not only is the outside world viewed negatively but the ego itself is compromised. The person's decline of self-perception is revealed in his belief of his own blame, inferiority, and unworthiness. He also emphasized early life experiences as a predisposing factor. Adolf Meyer put forward a mixed social and biological framework emphasizing reactions in the context of an individual's life, and argued that the term depression should be used instead of melancholia. The first version of the DSM (DSM-I, 1952) contained depressive reaction and the DSM-II (1968) depressive neurosis, defined as an excessive reaction to internal conflict or an identifiable event, and also included a depressive type of manic-depressive psychosis within Major affective disorders.
The term unipolar (along with the related term bipolar) was coined by the neurologist and psychiatrist Karl Kleist, and subsequently used by his disciples Edda Neele and Karl Leonhard.
The term Major depressive disorder was introduced by a group of US clinicians in the mid-1970s as part of proposals for diagnostic criteria based on patterns of symptoms (called the "Research Diagnostic Criteria", building on earlier Feighner Criteria), and was incorporated into the DSM-III in 1980. The American Psychiatric Association added "major depressive disorder" to the Diagnostic and Statistical Manual of Mental Disorders (DSM-III), as a split of the previous depressive neurosis in the DSM-II, which also encompassed the conditions now known as dysthymia and adjustment disorder with depressed mood. To maintain consistency the ICD-10 used the same criteria, with only minor alterations, but using the DSM diagnostic threshold to mark a mild depressive episode, adding higher threshold categories for moderate and severe episodes. The ancient idea of melancholia still survives in the notion of a melancholic subtype.
The new definitions of depression were widely accepted, albeit with some conflicting findings and views. There have been some continued empirically based arguments for a return to the diagnosis of melancholia. There has been some criticism of the expansion of coverage of the diagnosis, related to the development and promotion of antidepressants and the biological model since the late 1950s.
The term "depression" is used in a number of different ways. It is often used to mean this syndrome but may refer to other mood disorders or simply to a low mood. People's conceptualizations of depression vary widely, both within and among cultures. "Because of the lack of scientific certainty," one commentator has observed, "the debate over depression turns on questions of language. What we call it—'disease,' 'disorder,' 'state of mind'—affects how we view, diagnose, and treat it." There are cultural differences in the extent to which serious depression is considered an illness requiring personal professional treatment, or an indicator of something else, such as the need to address social or moral problems, the result of biological imbalances, or a reflection of individual differences in the understanding of distress that may reinforce feelings of powerlessness, and emotional struggle.
Historical figures were often reluctant to discuss or seek treatment for depression due to social stigma about the condition, or due to ignorance of diagnosis or treatments. Nevertheless, analysis or interpretation of letters, journals, artwork, writings, or statements of family and friends of some historical personalities has led to the presumption that they may have had some form of depression. People who may have had depression include English author Mary Shelley, American-British writer Henry James, and American president Abraham Lincoln. Some well-known contemporary people with possible depression include Canadian songwriter Leonard Cohen and American playwright and novelist Tennessee Williams. Some pioneering psychologists, such as Americans William James and John B. Watson, dealt with their own depression.
There has been a continuing discussion of whether neurological disorders and mood disorders may be linked to creativity, a discussion that goes back to Aristotelian times. British literature gives many examples of reflections on depression. English philosopher John Stuart Mill experienced a several-months-long period of what he called "a dull state of nerves", when one is "unsusceptible to enjoyment or pleasurable excitement; one of those moods when what is pleasure at other times, becomes insipid or indifferent". He quoted English poet Samuel Taylor Coleridge's "Dejection" as a perfect description of his case: "A grief without a pang, void, dark and drear, / A drowsy, stifled, unimpassioned grief, / Which finds no natural outlet or relief / In word, or sigh, or tear." English writer Samuel Johnson used the term "the black dog" in the 1780s to describe his own depression, and it was subsequently popularized by British Prime Minister Sir Winston Churchill, who also had the disorder. Johann Wolfgang von Goethe in his Faust, Part I, published in 1808, has Mephistopheles assume the form of a black dog, specifically a poodle.
Social stigma of major depression is widespread, and contact with mental health services reduces this only slightly. Public opinions on treatment differ markedly to those of health professionals; alternative treatments are held to be more helpful than pharmacological ones, which are viewed poorly. In the UK, the Royal College of Psychiatrists and the Royal College of General Practitioners conducted a joint Five-year Defeat Depression campaign to educate and reduce stigma from 1992 to 1996; a MORI study conducted afterwards showed a small positive change in public attitudes to depression and treatment.
While serving his first term as Prime Minister of Norway, Kjell Magne Bondevik attracted international attention in August 1998 when he announced that he was suffering from a depressive episode, becoming the highest ranking world leader to admit to suffering from a mental illness while in office. Upon this revelation, Anne Enger became acting Prime Minister for three weeks, from 30 August to 23 September, while he recovered from the depressive episode. Bondevik then returned to office. Bondevik received thousands of supportive letters, and said that the experience had been positive overall, both for himself and because it made mental illness more publicly acceptable. | [
{
"paragraph_id": 0,
"text": "Major depressive disorder (MDD), also known as clinical depression, is a mental disorder characterized by at least two weeks of pervasive low mood, low self-esteem, and loss of interest or pleasure in normally enjoyable activities. Introduced by a group of US clinicians in the mid-1970s, the term was adopted by the American Psychiatric Association for this symptom cluster under mood disorders in the 1980 version of the Diagnostic and Statistical Manual of Mental Disorders (DSM-III), and has become widely used since.",
"title": ""
},
{
"paragraph_id": 1,
"text": "The diagnosis of major depressive disorder is based on the person's reported experiences, behavior reported by relatives or friends, and a mental status examination. There is no laboratory test for the disorder, but testing may be done to rule out physical conditions that can cause similar symptoms. The most common time of onset is in a person's 20s, with females affected about twice as often as males. The course of the disorder varies widely, from one episode lasting months to a lifelong disorder with recurrent major depressive episodes.",
"title": ""
},
{
"paragraph_id": 2,
"text": "Those with major depressive disorder are typically treated with psychotherapy and antidepressant medication. Medication appears to be effective, but the effect may be significant only in the most severely depressed. Hospitalization (which may be involuntary) may be necessary in cases with associated self-neglect or a significant risk of harm to self or others. Electroconvulsive therapy (ECT) may be considered if other measures are not effective.",
"title": ""
},
{
"paragraph_id": 3,
"text": "Major depressive disorder is believed to be caused by a combination of genetic, environmental, and psychological factors, with about 40% of the risk being genetic. Risk factors include a family history of the condition, major life changes, certain medications, chronic health problems, and substance use disorders. It can negatively affect a person's personal life, work life, or education, and cause issues with a person's sleeping habits, eating habits, and general health. Major depressive disorder affected approximately 163 million people (2% of the world's population) in 2017. The percentage of people who are affected at one point in their life varies from 7% in Japan to 21% in France. Lifetime rates are higher in the developed world (15%) compared to the developing world (11%). The disorder causes the second-most years lived with disability, after lower back pain.",
"title": ""
},
{
"paragraph_id": 4,
"text": "Major depression significantly affects a person's family and personal relationships, work or school life, sleeping and eating habits, and general health. A person having a major depressive episode usually exhibits a low mood, which pervades all aspects of life, and an inability to experience pleasure in previously enjoyable activities. Depressed people may be preoccupied with—or ruminate over—thoughts and feelings of worthlessness, inappropriate guilt or regret, helplessness or hopelessness.",
"title": "Symptoms and signs"
},
{
"paragraph_id": 5,
"text": "Other symptoms of depression include poor concentration and memory, withdrawal from social situations and activities, reduced sex drive, irritability, and thoughts of death or suicide. Insomnia is common; in the typical pattern, a person wakes very early and cannot get back to sleep. Hypersomnia, or oversleeping, can also happen, as well as day-night rhythm disturbances, such as diurnal mood variation. Some antidepressants may also cause insomnia due to their stimulating effect. In severe cases, depressed people may have psychotic symptoms. These symptoms include delusions or, less commonly, hallucinations, usually unpleasant. People who have had previous episodes with psychotic symptoms are more likely to have them with future episodes.",
"title": "Symptoms and signs"
},
{
"paragraph_id": 6,
"text": "A depressed person may report multiple physical symptoms such as fatigue, headaches, or digestive problems; physical complaints are the most common presenting problem in developing countries, according to the World Health Organization's criteria for depression. Appetite often decreases, resulting in weight loss, although increased appetite and weight gain occasionally occur. Family and friends may notice agitation or lethargy. Older depressed people may have cognitive symptoms of recent onset, such as forgetfulness, and a more noticeable slowing of movements.",
"title": "Symptoms and signs"
},
{
"paragraph_id": 7,
"text": "Depressed children may often display an irritable rather than a depressed mood; most lose interest in school and show a steep decline in academic performance. Diagnosis may be delayed or missed when symptoms are interpreted as \"normal moodiness.\" Elderly people may not present with classical depressive symptoms. Diagnosis and treatment is further complicated in that the elderly are often simultaneously treated with a number of other drugs, and often have other concurrent diseases.",
"title": "Symptoms and signs"
},
{
"paragraph_id": 8,
"text": "The etiology of depression is not yet fully understood. The biopsychosocial model proposes that biological, psychological, and social factors all play a role in causing depression. The diathesis–stress model specifies that depression results when a preexisting vulnerability, or diathesis, is activated by stressful life events. The preexisting vulnerability can be either genetic, implying an interaction between nature and nurture, or schematic, resulting from views of the world learned in childhood. American psychiatrist Aaron Beck suggested that a triad of automatic and spontaneous negative thoughts about the self, the world or environment, and the future may lead to other depressive signs and symptoms.",
"title": "Cause"
},
{
"paragraph_id": 9,
"text": "Genes play a major role in the development of depression. Family and twin studies find that nearly 40% of individual differences in risk for major depressive disorder can be explained by genetic factors. Like most psychiatric disorders, major depressive disorder is likely influenced by many individual genetic changes. In 2018, a genome-wide association study discovered 44 genetic variants linked to risk for major depression; a 2019 study found 102 variants in the genome linked to depression. However, it appears that major depression is less heritable compared to bipolar disorder and schizophrenia. Research focusing on specific candidate genes has been criticized for its tendency to generate false positive findings. There are also other efforts to examine interactions between life stress and polygenic risk for depression.",
"title": "Cause"
},
{
"paragraph_id": 10,
"text": "Depression can also arise after a chronic or terminal medical condition, such as HIV/AIDS or asthma, and may be labeled \"secondary depression.\" It is unknown whether the underlying diseases induce depression through effect on quality of life, or through shared etiologies (such as degeneration of the basal ganglia in Parkinson's disease or immune dysregulation in asthma). Depression may also be iatrogenic (the result of healthcare), such as drug-induced depression. Therapies associated with depression include interferons, beta-blockers, isotretinoin, contraceptives, cardiac agents, anticonvulsants, antimigraine drugs, antipsychotics, and hormonal agents such as gonadotropin-releasing hormone agonist (GnRH agonist).",
"title": "Cause"
},
{
"paragraph_id": 11,
"text": "Substance use in early age is associated with increased risk of developing depression later in life. Depression occurring after giving birth is called postpartum depression and is thought to be the result of hormonal changes associated with pregnancy. Seasonal affective disorder, a type of depression associated with seasonal changes in sunlight, is thought to be triggered by decreased sunlight. Vitamin B2, B6 and B12 deficiency may cause depression in females.",
"title": "Cause"
},
{
"paragraph_id": 12,
"text": "Adverse childhood experiences (incorporating childhood abuse, neglect and family dysfunction) markedly increase the risk of major depression, especially if more than one type. Childhood trauma also correlates with severity of depression, poor responsiveness to treatment and length of illness. Some are more susceptible than others to developing mental illness such as depression after trauma, and various genes have been suggested to control susceptibility. Couples in unhappy marriages have a higher risk of developing clinical depression.",
"title": "Cause"
},
{
"paragraph_id": 13,
"text": "There appears to be a link between air pollution and depression and suicide. There may be an association between long-term PM2.5 exposure and depression, and a possible association between short-term PM10 exposure and suicide.",
"title": "Cause"
},
{
"paragraph_id": 14,
"text": "The pathophysiology of depression is not completely understood, but current theories center around monoaminergic systems, the circadian rhythm, immunological dysfunction, HPA-axis dysfunction and structural or functional abnormalities of emotional circuits.",
"title": "Pathophysiology"
},
{
"paragraph_id": 15,
"text": "Derived from the effectiveness of monoaminergic drugs in treating depression, the monoamine theory posits that insufficient activity of monoamine neurotransmitters is the primary cause of depression. Evidence for the monoamine theory comes from multiple areas. First, acute depletion of tryptophan—a necessary precursor of serotonin and a monoamine—can cause depression in those in remission or relatives of people who are depressed, suggesting that decreased serotonergic neurotransmission is important in depression. Second, the correlation between depression risk and polymorphisms in the 5-HTTLPR gene, which codes for serotonin receptors, suggests a link. Third, decreased size of the locus coeruleus, decreased activity of tyrosine hydroxylase, increased density of alpha-2 adrenergic receptor, and evidence from rat models suggest decreased adrenergic neurotransmission in depression. Furthermore, decreased levels of homovanillic acid, altered response to dextroamphetamine, responses of depressive symptoms to dopamine receptor agonists, decreased dopamine receptor D1 binding in the striatum, and polymorphism of dopamine receptor genes implicate dopamine, another monoamine, in depression. Lastly, increased activity of monoamine oxidase, which degrades monoamines, has been associated with depression. However, the monoamine theory is inconsistent with observations that serotonin depletion does not cause depression in healthy persons, that antidepressants instantly increase levels of monoamines but take weeks to work, and the existence of atypical antidepressants which can be effective despite not targeting this pathway.",
"title": "Pathophysiology"
},
{
"paragraph_id": 16,
"text": "One proposed explanation for the therapeutic lag, and further support for the deficiency of monoamines, is a desensitization of self-inhibition in raphe nuclei by the increased serotonin mediated by antidepressants. However, disinhibition of the dorsal raphe has been proposed to occur as a result of decreased serotonergic activity in tryptophan depletion, resulting in a depressed state mediated by increased serotonin. Further countering the monoamine hypothesis is the fact that rats with lesions of the dorsal raphe are not more depressive than controls, the finding of increased jugular 5-HIAA in people who are depressed that normalized with selective serotonin reuptake inhibitor (SSRI) treatment, and the preference for carbohydrates in people who are depressed. Already limited, the monoamine hypothesis has been further oversimplified when presented to the general public. A 2022 review found no consistent evidence supporting the serotonin hypothesis, linking serotonin levels and depression.",
"title": "Pathophysiology"
},
{
"paragraph_id": 17,
"text": "Immune system abnormalities have been observed, including increased levels of cytokines involved in generating sickness behavior (which shares overlap with depression). The effectiveness of nonsteroidal anti-inflammatory drugs (NSAIDs) and cytokine inhibitors in treating depression, and normalization of cytokine levels after successful treatment further suggest immune system abnormalities in depression.",
"title": "Pathophysiology"
},
{
"paragraph_id": 18,
"text": "HPA-axis abnormalities have been suggested in depression given the association of CRHR1 with depression and the increased frequency of dexamethasone test non-suppression in people who are depressed. However, this abnormality is not adequate as a diagnosis tool, because its sensitivity is only 44%. These stress-related abnormalities are thought to be the cause of hippocampal volume reductions seen in people who are depressed. Furthermore, a meta-analysis yielded decreased dexamethasone suppression, and increased response to psychological stressors. Further abnormal results have been obscured with the cortisol awakening response, with increased response being associated with depression.",
"title": "Pathophysiology"
},
{
"paragraph_id": 19,
"text": "Theories unifying neuroimaging findings have been proposed. The first model proposed is the limbic-cortical model, which involves hyperactivity of the ventral paralimbic regions and hypoactivity of frontal regulatory regions in emotional processing. Another model, the cortico-striatal model, suggests that abnormalities of the prefrontal cortex in regulating striatal and subcortical structures result in depression. Another model proposes hyperactivity of salience structures in identifying negative stimuli, and hypoactivity of cortical regulatory structures resulting in a negative emotional bias and depression, consistent with emotional bias studies.",
"title": "Pathophysiology"
},
{
"paragraph_id": 20,
"text": "A diagnostic assessment may be conducted by a suitably trained general practitioner, or by a psychiatrist or psychologist, who records the person's current circumstances, biographical history, current symptoms, family history, and alcohol and drug use. The assessment also includes a mental state examination, which is an assessment of the person's current mood and thought content, in particular the presence of themes of hopelessness or pessimism, self-harm or suicide, and an absence of positive thoughts or plans. Specialist mental health services are rare in rural areas, and thus diagnosis and management is left largely to primary-care clinicians. This issue is even more marked in developing countries. Rating scales are not used to diagnose depression, but they provide an indication of the severity of symptoms for a time period, so a person who scores above a given cut-off point can be more thoroughly evaluated for a depressive disorder diagnosis. Several rating scales are used for this purpose; these include the Hamilton Rating Scale for Depression, the Beck Depression Inventory or the Suicide Behaviors Questionnaire-Revised.",
"title": "Diagnosis"
},
{
"paragraph_id": 21,
"text": "Primary-care physicians have more difficulty with underrecognition and undertreatment of depression compared to psychiatrists. These cases may be missed because for some people with depression, physical symptoms often accompany depression. In addition, there may also be barriers related to the person, provider, and/or the medical system. Non-psychiatrist physicians have been shown to miss about two-thirds of cases, although there is some evidence of improvement in the number of missed cases.",
"title": "Diagnosis"
},
{
"paragraph_id": 22,
"text": "A doctor generally performs a medical examination and selected investigations to rule out other causes of depressive symptoms. These include blood tests measuring TSH and thyroxine to exclude hypothyroidism; basic electrolytes and serum calcium to rule out a metabolic disturbance; and a full blood count including ESR to rule out a systemic infection or chronic disease. Adverse affective reactions to medications or alcohol misuse may be ruled out, as well. Testosterone levels may be evaluated to diagnose hypogonadism, a cause of depression in men. Vitamin D levels might be evaluated, as low levels of vitamin D have been associated with greater risk for depression. Subjective cognitive complaints appear in older depressed people, but they can also be indicative of the onset of a dementing disorder, such as Alzheimer's disease. Cognitive testing and brain imaging can help distinguish depression from dementia. A CT scan can exclude brain pathology in those with psychotic, rapid-onset or otherwise unusual symptoms. No biological tests confirm major depression. In general, investigations are not repeated for a subsequent episode unless there is a medical indication.",
"title": "Diagnosis"
},
{
"paragraph_id": 23,
"text": "The most widely used criteria for diagnosing depressive conditions are found in the American Psychiatric Association's Diagnostic and Statistical Manual of Mental Disorders (DSM) and the World Health Organization's International Statistical Classification of Diseases and Related Health Problems (ICD). The latter system is typically used in European countries, while the former is used in the US and many other non-European nations, and the authors of both have worked towards conforming one with the other. Both DSM and ICD mark out typical (main) depressive symptoms. The most recent edition of the DSM is the Fifth Edition, Text Revision (DSM-5-TR), and the most recent edition of the ICD is the Eleventh Edition (ICD-11).",
"title": "Diagnosis"
},
{
"paragraph_id": 24,
"text": "Under mood disorders, ICD-11 classifies major depressive disorder as either single episode depressive disorder (where there is no history of depressive episodes, or of mania) or recurrent depressive disorder (where there is a history of prior episodes, with no history of mania). ICD-11 symptoms, present nearly every day for at least two weeks, are a depressed mood or anhedonia, accompanied by other symptoms such as \"difficulty concentrating, feelings of worthlessness or excessive or inappropriate guilt, hopelessness, recurrent thoughts of death or suicide, changes in appetite or sleep, psychomotor agitation or retardation, and reduced energy or fatigue.\" These symptoms must affect work, social, or domestic activities. The ICD-11 system allows further specifiers for the current depressive episode: the severity (mild, moderate, severe, unspecified); the presence of psychotic symptoms (with or without psychotic symptoms); and the degree of remission if relevant (currently in partial remission, currently in full remission). These two disorders are classified as \"Depressive disorders\", in the category of \"Mood disorders\".",
"title": "Diagnosis"
},
{
"paragraph_id": 25,
"text": "According to DSM-5, there are two main depressive symptoms: a depressed mood, and loss of interest/pleasure in activities (anhedonia). These symptoms, as well as five out of the nine more specific symptoms listed, must frequently occur for more than two weeks (to the extent in which it impairs functioning) for the diagnosis. Major depressive disorder is classified as a mood disorder in the DSM-5. The diagnosis hinges on the presence of single or recurrent major depressive episodes. Further qualifiers are used to classify both the episode itself and the course of the disorder. The category Unspecified Depressive Disorder is diagnosed if the depressive episode's manifestation does not meet the criteria for a major depressive episode.",
"title": "Diagnosis"
},
{
"paragraph_id": 26,
"text": "A major depressive episode is characterized by the presence of a severely depressed mood that persists for at least two weeks. Episodes may be isolated or recurrent and are categorized as mild (few symptoms in excess of minimum criteria), moderate, or severe (marked impact on social or occupational functioning). An episode with psychotic features—commonly referred to as psychotic depression—is automatically rated as severe. If the person has had an episode of mania or markedly elevated mood, a diagnosis of bipolar disorder is made instead. Depression without mania is sometimes referred to as unipolar because the mood remains at one emotional state or \"pole\".",
"title": "Diagnosis"
},
{
"paragraph_id": 27,
"text": "Bereavement is not an exclusion criterion in the DSM-5, and it is up to the clinician to distinguish between normal reactions to a loss and MDD. Excluded are a range of related diagnoses, including dysthymia, which involves a chronic but milder mood disturbance; recurrent brief depression, consisting of briefer depressive episodes; minor depressive disorder, whereby only some symptoms of major depression are present; and adjustment disorder with depressed mood, which denotes low mood resulting from a psychological response to an identifiable event or stressor.",
"title": "Diagnosis"
},
{
"paragraph_id": 28,
"text": "The DSM-5 recognizes six further subtypes of MDD, called specifiers, in addition to noting the length, severity and presence of psychotic features:",
"title": "Diagnosis"
},
{
"paragraph_id": 29,
"text": "To confirm major depressive disorder as the most likely diagnosis, other potential diagnoses must be considered, including dysthymia, adjustment disorder with depressed mood, or bipolar disorder. Dysthymia is a chronic, milder mood disturbance in which a person reports a low mood almost daily over a span of at least two years. The symptoms are not as severe as those for major depression, although people with dysthymia are vulnerable to secondary episodes of major depression (sometimes referred to as double depression). Adjustment disorder with depressed mood is a mood disturbance appearing as a psychological response to an identifiable event or stressor, in which the resulting emotional or behavioral symptoms are significant but do not meet the criteria for a major depressive episode.",
"title": "Diagnosis"
},
{
"paragraph_id": 30,
"text": "Other disorders need to be ruled out before diagnosing major depressive disorder. They include depressions due to physical illness, medications, and substance use disorders. Depression due to physical illness is diagnosed as a mood disorder due to a general medical condition. This condition is determined based on history, laboratory findings, or physical examination. When the depression is caused by a medication, non-medical use of a psychoactive substance, or exposure to a toxin, it is then diagnosed as a specific mood disorder (previously called substance-induced mood disorder).",
"title": "Diagnosis"
},
{
"paragraph_id": 31,
"text": "Preventive efforts may result in decreases in rates of the condition of between 22 and 38%. Since 2016, the United States Preventive Services Task Force (USPSTF) has recommended screening for depression among those over the age 12; though a 2005 Cochrane review found that the routine use of screening questionnaires has little effect on detection or treatment. Screening the general population is not recommended by authorities in the UK or Canada.",
"title": "Screening and prevention"
},
{
"paragraph_id": 32,
"text": "Behavioral interventions, such as interpersonal therapy and cognitive-behavioral therapy, are effective at preventing new onset depression. Because such interventions appear to be most effective when delivered to individuals or small groups, it has been suggested that they may be able to reach their large target audience most efficiently through the Internet.",
"title": "Screening and prevention"
},
{
"paragraph_id": 33,
"text": "The Netherlands mental health care system provides preventive interventions, such as the \"Coping with Depression\" course (CWD) for people with sub-threshold depression. The course is claimed to be the most successful of psychoeducational interventions for the treatment and prevention of depression (both for its adaptability to various populations and its results), with a risk reduction of 38% in major depression and an efficacy as a treatment comparing favorably to other psychotherapies.",
"title": "Screening and prevention"
},
{
"paragraph_id": 34,
"text": "The most common and effective treatments for depression are psychotherapy, medication, and electroconvulsive therapy (ECT); a combination of treatments is the most effective approach when depression is resistant to treatment. American Psychiatric Association treatment guidelines recommend that initial treatment should be individually tailored based on factors including severity of symptoms, co-existing disorders, prior treatment experience, and personal preference. Options may include pharmacotherapy, psychotherapy, exercise, ECT, transcranial magnetic stimulation (TMS) or light therapy. Antidepressant medication is recommended as an initial treatment choice in people with mild, moderate, or severe major depression, and should be given to all people with severe depression unless ECT is planned. There is evidence that collaborative care by a team of health care practitioners produces better results than routine single-practitioner care.",
"title": "Management"
},
{
"paragraph_id": 35,
"text": "Psychotherapy is the treatment of choice (over medication) for people under 18, and cognitive behavioral therapy (CBT), third wave CBT and interpersonal therapy may help prevent depression. The UK National Institute for Health and Care Excellence (NICE) 2004 guidelines indicate that antidepressants should not be used for the initial treatment of mild depression because the risk-benefit ratio is poor. The guidelines recommend that antidepressants treatment in combination with psychosocial interventions should be considered for:",
"title": "Management"
},
{
"paragraph_id": 36,
"text": "The guidelines further note that antidepressant treatment should be continued for at least six months to reduce the risk of relapse, and that SSRIs are better tolerated than tricyclic antidepressants.",
"title": "Management"
},
{
"paragraph_id": 37,
"text": "Treatment options are more limited in developing countries, where access to mental health staff, medication, and psychotherapy is often difficult. Development of mental health services is minimal in many countries; depression is viewed as a phenomenon of the developed world despite evidence to the contrary, and not as an inherently life-threatening condition. There is insufficient evidence to determine the effectiveness of psychological versus medical therapy in children.",
"title": "Management"
},
{
"paragraph_id": 38,
"text": "Physical exercise has been found to be effective for major depression, and may be recommended to people who are willing, motivated, and healthy enough to participate in an exercise program as treatment. It is equivalent to the use of medications or psychological therapies in most people. In older people it does appear to decrease depression. Sleep and diet may also play a role in depression, and interventions in these areas may be an effective add-on to conventional methods. In observational studies, smoking cessation has benefits in depression as large as or larger than those of medications.",
"title": "Management"
},
{
"paragraph_id": 39,
"text": "Talking therapy (psychotherapy) can be delivered to individuals, groups, or families by mental health professionals, including psychotherapists, psychiatrists, psychologists, clinical social workers, counselors, and psychiatric nurses. A 2012 review found psychotherapy to be better than no treatment but not other treatments. With more complex and chronic forms of depression, a combination of medication and psychotherapy may be used. There is moderate-quality evidence that psychological therapies are a useful addition to standard antidepressant treatment of treatment-resistant depression in the short term. Psychotherapy has been shown to be effective in older people. Successful psychotherapy appears to reduce the recurrence of depression even after it has been stopped or replaced by occasional booster sessions.",
"title": "Management"
},
{
"paragraph_id": 40,
"text": "The most-studied form of psychotherapy for depression is CBT, which teaches clients to challenge self-defeating, but enduring ways of thinking (cognitions) and change counter-productive behaviors. CBT can perform as well as antidepressants in people with major depression. CBT has the most research evidence for the treatment of depression in children and adolescents, and CBT and interpersonal psychotherapy (IPT) are preferred therapies for adolescent depression. In people under 18, according to the National Institute for Health and Clinical Excellence, medication should be offered only in conjunction with a psychological therapy, such as CBT, interpersonal therapy, or family therapy. Several variables predict success for cognitive behavioral therapy in adolescents: higher levels of rational thoughts, less hopelessness, fewer negative thoughts, and fewer cognitive distortions. CBT is particularly beneficial in preventing relapse. Cognitive behavioral therapy and occupational programs (including modification of work activities and assistance) have been shown to be effective in reducing sick days taken by workers with depression. Several variants of cognitive behavior therapy have been used in those with depression, the most notable being rational emotive behavior therapy, and mindfulness-based cognitive therapy. Mindfulness-based stress reduction programs may reduce depression symptoms. Mindfulness programs also appear to be a promising intervention in youth. Problem solving therapy, cognitive behavioral therapy, and interpersonal therapy are effective interventions in the elderly.",
"title": "Management"
},
{
"paragraph_id": 41,
"text": "Psychoanalysis is a school of thought, founded by Sigmund Freud, which emphasizes the resolution of unconscious mental conflicts. Psychoanalytic techniques are used by some practitioners to treat clients presenting with major depression. A more widely practiced therapy, called psychodynamic psychotherapy, is in the tradition of psychoanalysis but less intensive, meeting once or twice a week. It also tends to focus more on the person's immediate problems, and has an additional social and interpersonal focus. In a meta-analysis of three controlled trials of Short Psychodynamic Supportive Psychotherapy, this modification was found to be as effective as medication for mild to moderate depression.",
"title": "Management"
},
{
"paragraph_id": 42,
"text": "Conflicting results have arisen from studies that look at the effectiveness of antidepressants in people with acute, mild to moderate depression. A review commissioned by the National Institute for Health and Care Excellence (UK) concluded that there is strong evidence that SSRIs, such as escitalopram, paroxetine, and sertraline, have greater efficacy than placebo on achieving a 50% reduction in depression scores in moderate and severe major depression, and that there is some evidence for a similar effect in mild depression. Similarly, a Cochrane systematic review of clinical trials of the generic tricyclic antidepressant amitriptyline concluded that there is strong evidence that its efficacy is superior to placebo. Antidepressants work less well for the elderly than for younger individuals with depression.",
"title": "Management"
},
{
"paragraph_id": 43,
"text": "To find the most effective antidepressant medication with minimal side-effects, the dosages can be adjusted, and if necessary, combinations of different classes of antidepressants can be tried. Response rates to the first antidepressant administered range from 50 to 75%, and it can take at least six to eight weeks from the start of medication to improvement. Antidepressant medication treatment is usually continued for 16 to 20 weeks after remission, to minimize the chance of recurrence, and even up to one year of continuation is recommended. People with chronic depression may need to take medication indefinitely to avoid relapse.",
"title": "Management"
},
{
"paragraph_id": 44,
"text": "SSRIs are the primary medications prescribed, owing to their relatively mild side-effects, and because they are less toxic in overdose than other antidepressants. People who do not respond to one SSRI can be switched to another antidepressant, and this results in improvement in almost 50% of cases. Another option is to switch to the atypical antidepressant bupropion. Venlafaxine, an antidepressant with a different mechanism of action, may be modestly more effective than SSRIs. However, venlafaxine is not recommended in the UK as a first-line treatment because of evidence suggesting its risks may outweigh benefits, and it is specifically discouraged in children and adolescents as it increases the risk of suicidal thoughts or attempts.",
"title": "Management"
},
{
"paragraph_id": 45,
"text": "For children and adolescents with moderate-to-severe depressive disorder, fluoxetine seems to be the best treatment (either with or without cognitive behavioural therapy) but more research is needed to be certain. Sertraline, escitalopram, duloxetine might also help in reducing symptoms. Some antidepressants have not been shown to be effective. Medications are not recommended in children with mild disease.",
"title": "Management"
},
{
"paragraph_id": 46,
"text": "There is also insufficient evidence to determine effectiveness in those with depression complicated by dementia. Any antidepressant can cause low blood sodium levels; nevertheless, it has been reported more often with SSRIs. It is not uncommon for SSRIs to cause or worsen insomnia; the sedating atypical antidepressant mirtazapine can be used in such cases.",
"title": "Management"
},
{
"paragraph_id": 47,
"text": "Irreversible monoamine oxidase inhibitors, an older class of antidepressants, have been plagued by potentially life-threatening dietary and drug interactions. They are still used only rarely, although newer and better-tolerated agents of this class have been developed. The safety profile is different with reversible monoamine oxidase inhibitors, such as moclobemide, where the risk of serious dietary interactions is negligible and dietary restrictions are less strict.",
"title": "Management"
},
{
"paragraph_id": 48,
"text": "It is unclear whether antidepressants affect a person's risk of suicide. For children, adolescents, and probably young adults between 18 and 24 years old, there is a higher risk of both suicidal ideations and suicidal behavior in those treated with SSRIs. For adults, it is unclear whether SSRIs affect the risk of suicidality. One review found no connection; another an increased risk; and a third no risk in those 25–65 years old and a decreased risk in those more than 65. A black box warning was introduced in the United States in 2007 on SSRIs and other antidepressant medications due to the increased risk of suicide in people younger than 24 years old. Similar precautionary notice revisions were implemented by the Japanese Ministry of Health.",
"title": "Management"
},
{
"paragraph_id": 49,
"text": "The combined use of antidepressants plus benzodiazepines demonstrates improved effectiveness when compared to antidepressants alone, but these effects may not endure. The addition of a benzodiazepine is balanced against possible harms and other alternative treatment strategies when antidepressant mono-therapy is considered inadequate.",
"title": "Management"
},
{
"paragraph_id": 50,
"text": "For treatment-resistant depression, adding on the atypical antipsychotic brexpiprazole for short-term or acute management may be considered. Brexpiprazole may be effective for some people, however, the evidence as of 2023 supporting its use is weak and this medication has potential adverse effects including weight gain and akathisia. Brexpiprazole has not been sufficiently studied in older people or children and the use and effectiveness of this adjunctive therapy for longer term management is not clear.",
"title": "Management"
},
{
"paragraph_id": 51,
"text": "Ketamine may have a rapid antidepressant effect lasting less than two weeks; there is limited evidence of any effect after that, common acute side effects, and longer-term studies of safety and adverse effects are needed. A nasal spray form of esketamine was approved by the FDA in March 2019 for use in treatment-resistant depression when combined with an oral antidepressant; risk of substance use disorder and concerns about its safety, serious adverse effects, tolerability, effect on suicidality, lack of information about dosage, whether the studies on it adequately represent broad populations, and escalating use of the product have been raised by an international panel of experts.",
"title": "Management"
},
{
"paragraph_id": 52,
"text": "There is insufficient high quality evidence to suggest omega-3 fatty acids are effective in depression. There is limited evidence that vitamin D supplementation is of value in alleviating the symptoms of depression in individuals who are vitamin D-deficient. Lithium appears effective at lowering the risk of suicide in those with bipolar disorder and unipolar depression to nearly the same levels as the general population. There is a narrow range of effective and safe dosages of lithium thus close monitoring may be needed. Low-dose thyroid hormone may be added to existing antidepressants to treat persistent depression symptoms in people who have tried multiple courses of medication. Limited evidence suggests stimulants, such as amphetamine and modafinil, may be effective in the short term, or as adjuvant therapy. Also, it is suggested that folate supplements may have a role in depression management. There is tentative evidence for benefit from testosterone in males.",
"title": "Management"
},
{
"paragraph_id": 53,
"text": "Electroconvulsive therapy (ECT) is a standard psychiatric treatment in which seizures are electrically induced in a person with depression to provide relief from psychiatric illnesses. ECT is used with informed consent as a last line of intervention for major depressive disorder. A round of ECT is effective for about 50% of people with treatment-resistant major depressive disorder, whether it is unipolar or bipolar. Follow-up treatment is still poorly studied, but about half of people who respond relapse within twelve months. Aside from effects in the brain, the general physical risks of ECT are similar to those of brief general anesthesia. Immediately following treatment, the most common adverse effects are confusion and memory loss. ECT is considered one of the least harmful treatment options available for severely depressed pregnant women.",
"title": "Management"
},
{
"paragraph_id": 54,
"text": "A usual course of ECT involves multiple administrations, typically given two or three times per week, until the person no longer has symptoms. ECT is administered under anesthesia with a muscle relaxant. Electroconvulsive therapy can differ in its application in three ways: electrode placement, frequency of treatments, and the electrical waveform of the stimulus. These three forms of application have significant differences in both adverse side effects and symptom remission. After treatment, drug therapy is usually continued, and some people receive maintenance ECT.",
"title": "Management"
},
{
"paragraph_id": 55,
"text": "ECT appears to work in the short term via an anticonvulsant effect mostly in the frontal lobes, and longer term via neurotrophic effects primarily in the medial temporal lobe.",
"title": "Management"
},
{
"paragraph_id": 56,
"text": "Transcranial magnetic stimulation (TMS) or deep transcranial magnetic stimulation is a noninvasive method used to stimulate small regions of the brain. TMS was approved by the FDA for treatment-resistant major depressive disorder (trMDD) in 2008 and as of 2014 evidence supports that it is probably effective. The American Psychiatric Association, the Canadian Network for Mood and Anxiety Disorders, and the Royal Australia and New Zealand College of Psychiatrists have endorsed TMS for trMDD. Transcranial direct current stimulation (tDCS) is another noninvasive method used to stimulate small regions of the brain with a weak electric current. Several meta-analyses have concluded that active tDCS was useful for treating depression.",
"title": "Management"
},
{
"paragraph_id": 57,
"text": "There is a small amount of evidence that sleep deprivation may improve depressive symptoms in some individuals, with the effects usually showing up within a day. This effect is usually temporary. Besides sleepiness, this method can cause a side effect of mania or hypomania. There is insufficient evidence for Reiki and dance movement therapy in depression. Cannabis is specifically not recommended as a treatment.",
"title": "Management"
},
{
"paragraph_id": 58,
"text": "Studies have shown that 80% of those with a first major depressive episode will have at least one more during their life, with a lifetime average of four episodes. Other general population studies indicate that around half those who have an episode recover (whether treated or not) and remain well, while the other half will have at least one more, and around 15% of those experience chronic recurrence. Studies recruiting from selective inpatient sources suggest lower recovery and higher chronicity, while studies of mostly outpatients show that nearly all recover, with a median episode duration of 11 months. Around 90% of those with severe or psychotic depression, most of whom also meet criteria for other mental disorders, experience recurrence. Cases when outcome is poor are associated with inappropriate treatment, severe initial symptoms including psychosis, early age of onset, previous episodes, incomplete recovery after one year of treatment, pre-existing severe mental or medical disorder, and family dysfunction.",
"title": "Prognosis"
},
{
"paragraph_id": 59,
"text": "A high proportion of people who experience full symptomatic remission still have at least one not fully resolved symptom after treatment. Recurrence or chronicity is more likely if symptoms have not fully resolved with treatment. Current guidelines recommend continuing antidepressants for four to six months after remission to prevent relapse. Evidence from many randomized controlled trials indicates continuing antidepressant medications after recovery can reduce the chance of relapse by 70% (41% on placebo vs. 18% on antidepressant). The preventive effect probably lasts for at least the first 36 months of use.",
"title": "Prognosis"
},
{
"paragraph_id": 60,
"text": "Major depressive episodes often resolve over time, whether or not they are treated. Outpatients on a waiting list show a 10–15% reduction in symptoms within a few months, with approximately 20% no longer meeting the full criteria for a depressive disorder. The median duration of an episode has been estimated to be 23 weeks, with the highest rate of recovery in the first three months. According to a 2013 review, 23% of untreated adults with mild to moderate depression will remit within 3 months, 32% within 6 months and 53% within 12 months.",
"title": "Prognosis"
},
{
"paragraph_id": 61,
"text": "Depression may affect people's ability to work. The combination of usual clinical care and support with return to work (like working less hours or changing tasks) probably reduces sick leave by 15%, and leads to fewer depressive symptoms and improved work capacity, reducing sick leave by an annual average of 25 days per year. Helping depressed people return to work without a connection to clinical care has not been shown to have an effect on sick leave days. Additional psychological interventions (such as online cognitive behavioral therapy) lead to fewer sick days compared to standard management only. Streamlining care or adding specific providers for depression care may help to reduce sick leave.",
"title": "Prognosis"
},
{
"paragraph_id": 62,
"text": "Depressed individuals have a shorter life expectancy than those without depression, in part because people who are depressed are at risk of dying of suicide. About 50% of people who die of suicide have a mood disorder such as major depression, and the risk is especially high if a person has a marked sense of hopelessness or has both depression and borderline personality disorder. About 2–8% of adults with major depression die by suicide. In the US, the lifetime risk of suicide associated with a diagnosis of major depression is estimated at 7% for men and 1% for women, even though suicide attempts are more frequent in women.",
"title": "Prognosis"
},
{
"paragraph_id": 63,
"text": "Depressed people have a higher rate of dying from other causes. There is a 1.5- to 2-fold increased risk of cardiovascular disease, independent of other known risk factors, and is itself linked directly or indirectly to risk factors such as smoking and obesity. People with major depression are less likely to follow medical recommendations for treating and preventing cardiovascular disorders, further increasing their risk of medical complications. Cardiologists may not recognize underlying depression that complicates a cardiovascular problem under their care.",
"title": "Prognosis"
},
{
"paragraph_id": 64,
"text": "Major depressive disorder affected approximately 163 million people in 2017 (2% of the global population). The percentage of people who are affected at one point in their life varies from 7% in Japan to 21% in France. In most countries the number of people who have depression during their lives falls within an 8–18% range.",
"title": "Epidemiology"
},
{
"paragraph_id": 65,
"text": "In the United States, 8.4% of adults (21 million individuals) have at least one episode within a year-long period; the probability of having a major depressive episode is higher for females than males (10.5% to 6.2%), and highest for those aged 18 to 25 (17%). Among adolescents between the ages of 12 and 17, 17% of the U.S. population (4.1 million individuals) had a major depressive episode in 2020 (females 25.2%, males 9.2%). Among individuals reporting two or more races, the US prevalence is highest.",
"title": "Epidemiology"
},
{
"paragraph_id": 66,
"text": "Major depression is about twice as common in women as in men, although it is unclear why this is so, and whether factors unaccounted for are contributing to this. The relative increase in occurrence is related to pubertal development rather than chronological age, reaches adult ratios between the ages of 15 and 18, and appears associated with psychosocial more than hormonal factors. In 2019, major depressive disorder was identified (using either the DSM-IV-TR or ICD-10) in the Global Burden of Disease Study as the fifth most common cause of years lived with disability and the 18th most common for disability-adjusted life years.",
"title": "Epidemiology"
},
{
"paragraph_id": 67,
"text": "People are most likely to develop their first depressive episode between the ages of 30 and 40, and there is a second, smaller peak of incidence between ages 50 and 60. The risk of major depression is increased with neurological conditions such as stroke, Parkinson's disease, or multiple sclerosis, and during the first year after childbirth. It is also more common after cardiovascular illnesses, and is related more to those with a poor cardiac disease outcome than to a better one. Depressive disorders are more common in urban populations than in rural ones and the prevalence is increased in groups with poorer socioeconomic factors, e.g., homelessness. Depression is common among those over 65 years of age and increases in frequency beyond this age. The risk of depression increases in relation to the frailty of the individual. Depression is one of the most important factors which negatively impact quality of life in adults, as well as the elderly. Both symptoms and treatment among the elderly differ from those of the rest of the population.",
"title": "Epidemiology"
},
{
"paragraph_id": 68,
"text": "Major depression was the leading cause of disease burden in North America and other high-income countries, and the fourth-leading cause worldwide as of 2006. In the year 2030, it is predicted to be the second-leading cause of disease burden worldwide after HIV, according to the WHO. Delay or failure in seeking treatment after relapse and the failure of health professionals to provide treatment are two barriers to reducing disability.",
"title": "Epidemiology"
},
{
"paragraph_id": 69,
"text": "Major depression frequently co-occurs with other psychiatric problems. The 1990–92 National Comorbidity Survey (US) reported that half of those with major depression also have lifetime anxiety and its associated disorders, such as generalized anxiety disorder. Anxiety symptoms can have a major impact on the course of a depressive illness, with delayed recovery, increased risk of relapse, greater disability and increased suicidal behavior. Depressed people have increased rates of alcohol and substance use, particularly dependence, and around a third of individuals diagnosed with attention deficit hyperactivity disorder (ADHD) develop comorbid depression. Post-traumatic stress disorder and depression often co-occur. Depression may also coexist with ADHD, complicating the diagnosis and treatment of both. Depression is also frequently comorbid with alcohol use disorder and personality disorders. Depression can also be exacerbated during particular months (usually winter) in those with seasonal affective disorder. While overuse of digital media has been associated with depressive symptoms, using digital media may also improve mood in some situations.",
"title": "Epidemiology"
},
{
"paragraph_id": 70,
"text": "Depression and pain often co-occur. One or more pain symptoms are present in 65% of people who have depression, and anywhere from 5 to 85% of people who are experiencing pain will also have depression, depending on the setting—a lower prevalence in general practice, and higher in specialty clinics. Depression is often underrecognized, and therefore undertreated, in patients presenting with pain. Depression often coexists with physical disorders common among the elderly, such as stroke, other cardiovascular diseases, Parkinson's disease, and chronic obstructive pulmonary disease.",
"title": "Epidemiology"
},
{
"paragraph_id": 71,
"text": "The Ancient Greek physician Hippocrates described a syndrome of melancholia (μελαγχολία, melankholía) as a distinct disease with particular mental and physical symptoms; he characterized all \"fears and despondencies, if they last a long time\" as being symptomatic of the ailment. It was a similar but far broader concept than today's depression; prominence was given to a clustering of the symptoms of sadness, dejection, and despondency, and often fear, anger, delusions and obsessions were included.",
"title": "History"
},
{
"paragraph_id": 72,
"text": "The term depression itself was derived from the Latin verb deprimere, meaning \"to press down\". From the 14th century, \"to depress\" meant to subjugate or to bring down in spirits. It was used in 1665 in English author Richard Baker's Chronicle to refer to someone having \"a great depression of spirit\", and by English author Samuel Johnson in a similar sense in 1753. The term also came into use in physiology and economics. An early usage referring to a psychiatric symptom was by French psychiatrist Louis Delasiauve in 1856, and by the 1860s it was appearing in medical dictionaries to refer to a physiological and metaphorical lowering of emotional function. Since Aristotle, melancholia had been associated with men of learning and intellectual brilliance, a hazard of contemplation and creativity. However, by the 19th century, this association has largely shifted and melancholia became more commonly linked with women.",
"title": "History"
},
{
"paragraph_id": 73,
"text": "Although melancholia remained the dominant diagnostic term, depression gained increasing currency in medical treatises and was a synonym by the end of the century; German psychiatrist Emil Kraepelin may have been the first to use it as the overarching term, referring to different kinds of melancholia as depressive states. Freud likened the state of melancholia to mourning in his 1917 paper Mourning and Melancholia. He theorized that objective loss, such as the loss of a valued relationship through death or a romantic break-up, results in subjective loss as well; the depressed individual has identified with the object of affection through an unconscious, narcissistic process called the libidinal cathexis of the ego. Such loss results in severe melancholic symptoms more profound than mourning; not only is the outside world viewed negatively but the ego itself is compromised. The person's decline of self-perception is revealed in his belief of his own blame, inferiority, and unworthiness. He also emphasized early life experiences as a predisposing factor. Adolf Meyer put forward a mixed social and biological framework emphasizing reactions in the context of an individual's life, and argued that the term depression should be used instead of melancholia. The first version of the DSM (DSM-I, 1952) contained depressive reaction and the DSM-II (1968) depressive neurosis, defined as an excessive reaction to internal conflict or an identifiable event, and also included a depressive type of manic-depressive psychosis within Major affective disorders.",
"title": "History"
},
{
"paragraph_id": 74,
"text": "The term unipolar (along with the related term bipolar) was coined by the neurologist and psychiatrist Karl Kleist, and subsequently used by his disciples Edda Neele and Karl Leonhard.",
"title": "History"
},
{
"paragraph_id": 75,
"text": "The term Major depressive disorder was introduced by a group of US clinicians in the mid-1970s as part of proposals for diagnostic criteria based on patterns of symptoms (called the \"Research Diagnostic Criteria\", building on earlier Feighner Criteria), and was incorporated into the DSM-III in 1980. The American Psychiatric Association added \"major depressive disorder\" to the Diagnostic and Statistical Manual of Mental Disorders (DSM-III), as a split of the previous depressive neurosis in the DSM-II, which also encompassed the conditions now known as dysthymia and adjustment disorder with depressed mood. To maintain consistency the ICD-10 used the same criteria, with only minor alterations, but using the DSM diagnostic threshold to mark a mild depressive episode, adding higher threshold categories for moderate and severe episodes. The ancient idea of melancholia still survives in the notion of a melancholic subtype.",
"title": "History"
},
{
"paragraph_id": 76,
"text": "The new definitions of depression were widely accepted, albeit with some conflicting findings and views. There have been some continued empirically based arguments for a return to the diagnosis of melancholia. There has been some criticism of the expansion of coverage of the diagnosis, related to the development and promotion of antidepressants and the biological model since the late 1950s.",
"title": "History"
},
{
"paragraph_id": 77,
"text": "The term \"depression\" is used in a number of different ways. It is often used to mean this syndrome but may refer to other mood disorders or simply to a low mood. People's conceptualizations of depression vary widely, both within and among cultures. \"Because of the lack of scientific certainty,\" one commentator has observed, \"the debate over depression turns on questions of language. What we call it—'disease,' 'disorder,' 'state of mind'—affects how we view, diagnose, and treat it.\" There are cultural differences in the extent to which serious depression is considered an illness requiring personal professional treatment, or an indicator of something else, such as the need to address social or moral problems, the result of biological imbalances, or a reflection of individual differences in the understanding of distress that may reinforce feelings of powerlessness, and emotional struggle.",
"title": "Society and culture"
},
{
"paragraph_id": 78,
"text": "Historical figures were often reluctant to discuss or seek treatment for depression due to social stigma about the condition, or due to ignorance of diagnosis or treatments. Nevertheless, analysis or interpretation of letters, journals, artwork, writings, or statements of family and friends of some historical personalities has led to the presumption that they may have had some form of depression. People who may have had depression include English author Mary Shelley, American-British writer Henry James, and American president Abraham Lincoln. Some well-known contemporary people with possible depression include Canadian songwriter Leonard Cohen and American playwright and novelist Tennessee Williams. Some pioneering psychologists, such as Americans William James and John B. Watson, dealt with their own depression.",
"title": "Society and culture"
},
{
"paragraph_id": 79,
"text": "There has been a continuing discussion of whether neurological disorders and mood disorders may be linked to creativity, a discussion that goes back to Aristotelian times. British literature gives many examples of reflections on depression. English philosopher John Stuart Mill experienced a several-months-long period of what he called \"a dull state of nerves\", when one is \"unsusceptible to enjoyment or pleasurable excitement; one of those moods when what is pleasure at other times, becomes insipid or indifferent\". He quoted English poet Samuel Taylor Coleridge's \"Dejection\" as a perfect description of his case: \"A grief without a pang, void, dark and drear, / A drowsy, stifled, unimpassioned grief, / Which finds no natural outlet or relief / In word, or sigh, or tear.\" English writer Samuel Johnson used the term \"the black dog\" in the 1780s to describe his own depression, and it was subsequently popularized by British Prime Minister Sir Winston Churchill, who also had the disorder. Johann Wolfgang von Goethe in his Faust, Part I, published in 1808, has Mephistopheles assume the form of a black dog, specifically a poodle.",
"title": "Society and culture"
},
{
"paragraph_id": 80,
"text": "Social stigma of major depression is widespread, and contact with mental health services reduces this only slightly. Public opinions on treatment differ markedly to those of health professionals; alternative treatments are held to be more helpful than pharmacological ones, which are viewed poorly. In the UK, the Royal College of Psychiatrists and the Royal College of General Practitioners conducted a joint Five-year Defeat Depression campaign to educate and reduce stigma from 1992 to 1996; a MORI study conducted afterwards showed a small positive change in public attitudes to depression and treatment.",
"title": "Society and culture"
},
{
"paragraph_id": 81,
"text": "While serving his first term as Prime Minister of Norway, Kjell Magne Bondevik attracted international attention in August 1998 when he announced that he was suffering from a depressive episode, becoming the highest ranking world leader to admit to suffering from a mental illness while in office. Upon this revelation, Anne Enger became acting Prime Minister for three weeks, from 30 August to 23 September, while he recovered from the depressive episode. Bondevik then returned to office. Bondevik received thousands of supportive letters, and said that the experience had been positive overall, both for himself and because it made mental illness more publicly acceptable.",
"title": "Society and culture"
}
] | Major depressive disorder (MDD), also known as clinical depression, is a mental disorder characterized by at least two weeks of pervasive low mood, low self-esteem, and loss of interest or pleasure in normally enjoyable activities. Introduced by a group of US clinicians in the mid-1970s, the term was adopted by the American Psychiatric Association for this symptom cluster under mood disorders in the 1980 version of the Diagnostic and Statistical Manual of Mental Disorders (DSM-III), and has become widely used since. The diagnosis of major depressive disorder is based on the person's reported experiences, behavior reported by relatives or friends, and a mental status examination. There is no laboratory test for the disorder, but testing may be done to rule out physical conditions that can cause similar symptoms. The most common time of onset is in a person's 20s, with females affected about twice as often as males. The course of the disorder varies widely, from one episode lasting months to a lifelong disorder with recurrent major depressive episodes. Those with major depressive disorder are typically treated with psychotherapy and antidepressant medication. Medication appears to be effective, but the effect may be significant only in the most severely depressed. Hospitalization may be necessary in cases with associated self-neglect or a significant risk of harm to self or others. Electroconvulsive therapy (ECT) may be considered if other measures are not effective. Major depressive disorder is believed to be caused by a combination of genetic, environmental, and psychological factors, with about 40% of the risk being genetic. Risk factors include a family history of the condition, major life changes, certain medications, chronic health problems, and substance use disorders. It can negatively affect a person's personal life, work life, or education, and cause issues with a person's sleeping habits, eating habits, and general health. Major depressive disorder affected approximately 163 million people in 2017. The percentage of people who are affected at one point in their life varies from 7% in Japan to 21% in France. Lifetime rates are higher in the developed world (15%) compared to the developing world (11%). The disorder causes the second-most years lived with disability, after lower back pain. | 2001-10-30T00:53:08Z | 2023-12-29T11:37:42Z | [
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8,391 | Diana (mythology) | Diana is a goddess in Roman and Hellenistic religion, primarily considered a patroness of the countryside and nature, hunters, wildlife, childbirth, crossroads, the night, and the Moon. She is equated with the Greek goddess Artemis, and absorbed much of Artemis' mythology early in Roman history, including a birth on the island of Delos to parents Jupiter and Latona, and a twin brother, Apollo, though she had an independent origin in Italy.
Diana is considered a virgin goddess and protector of childbirth. Historically, Diana made up a triad with two other Roman deities: Egeria the water nymph, her servant and assistant midwife; and Virbius, the woodland god.
Diana is revered in modern neopagan religions including Roman neopaganism, Stregheria, and Wicca. In the ancient, medieval, and modern periods, Diana has been considered a triple deity, merged with a goddess of the moon (Luna/Selene) and the underworld (usually Hecate).
The name Dīāna probably derives from Latin dīus ('godly'), ultimately from Proto-Italic *dīwī, meaning 'divine, heavenly'. It stems from Proto-Indo-European *diwyós ('divine, heavenly'), formed with the stem *dyew- ('daylight sky') attached the thematic suffix -yós. Cognates appear in Myceanean Greek di-wi-ja, in Ancient Greek dîos (δῖος; 'belonging to heaven, godlike'), and in Sanskrit divyá ('heavenly' or 'celestial').
The ancient Latin writers Varro and Cicero considered the etymology of Dīāna as allied to that of dies and connected to the shine of the Moon, noting that one of her titles is Diana Lucifera ("light-bearer").
... people regard Diana and the moon as one and the same. ... the moon (luna) is so called from the verb to shine (lucere). Lucina is identified with it, which is why in our country they invoke Juno Lucina in childbirth, just as the Greeks call on Diana the Light-bearer. Diana also has the name Omnivaga ("wandering everywhere"), not because of her hunting but because she is numbered as one of the seven planets; her name Diana derives from the fact that she turns darkness into daylight (dies). She is invoked at childbirth because children are born occasionally after seven, or usually after nine, lunar revolutions ...
The persona of Diana is complex, and contains a number of archaic features. Diana was originally considered to be a goddess of the wilderness and of the hunt, a central sport in both Roman and Greek culture. Early Roman inscriptions to Diana celebrated her primarily as a huntress and patron of hunters. Later, in the Hellenistic period, Diana came to be equally or more revered as a goddess not of the wild woodland but of the "tame" countryside, or villa rustica, the idealization of which was common in Greek thought and poetry. This dual role as goddess of both civilization and the wild, and therefore the civilized countryside, first applied to the Greek goddess Artemis (for example, in the 3rd century BCE poetry of Anacreon).
By the 3rd century CE, after Greek influence had a profound impact on Roman religion, Diana had been almost fully combined with Artemis and took on many of her attributes, both in her spiritual domains and in the description of her appearance. The Roman poet Nemesianus wrote a typical description of Diana: She carried a bow and a quiver full of golden arrows, wore a golden cloak, purple half-boots, and a belt with a jeweled buckle to hold her tunic together, and wore her hair gathered in a ribbon. By the 5th century CE, almost a millennia after her cult's entry into Rome, the philosopher Proclus could still characterize Diana as "the inspective guardian of every thing rural, [who] represses every thing rustic and uncultivated."
Diana was often considered an aspect of a triple goddess, known as Diana triformis: Diana, Luna, and Hecate. According to historian C.M. Green, "these were neither different goddesses nor an amalgamation of different goddesses. They were Diana...Diana as huntress, Diana as the moon, Diana of the underworld." At her sacred grove on the shores of Lake Nemi, Diana was venerated as a triple goddess beginning in the late 6th century BCE.
Andreas Alföldi interpreted an image on a late Republican coin as the Latin Diana "conceived as a threefold unity of the divine huntress, the Moon goddess and the goddess of the nether world, Hekate". This coin, minted by P. Accoleius Lariscolus in 43 BCE, has been acknowledged as representing an archaic statue of Diana Nemorensis. It represents Artemis with the bow at one extremity, Luna-Selene with flowers at the other and a central deity not immediately identifiable, all united by a horizontal bar. The iconographical analysis allows the dating of this image to the 6th century at which time there are Etruscan models. The coin shows that the triple goddess cult image still stood in the lucus of Nemi in 43 BCE. Lake Nemi was called Triviae lacus by Virgil (Aeneid 7.516), while Horace called Diana montium custos nemoremque virgo ("keeper of the mountains and virgin of Nemi") and diva triformis ("three-form goddess").
Two heads found in the sanctuary and the Roman theatre at Nemi, which have a hollow on their back, lend support to this interpretation of an archaic triple Diana.
The earliest epithet of Diana was Trivia, and she was addressed with that title by Virgil, Catullus, and many others. "Trivia" comes from the Latin trivium, "triple way", and refers to Diana's guardianship over roadways, particularly Y-junctions or three-way crossroads. This role carried a somewhat dark and dangerous connotation, as it metaphorically pointed the way to the underworld. In the 1st-century CE play Medea, Seneca's titular sorceress calls on Trivia to cast a magic spell. She evokes the triple goddess of Diana, Selene, and Hecate, and specifies that she requires the powers of the latter. The 1st century poet Horace similarly wrote of a magic incantation invoking the power of both Diana and Proserpina. The symbol of the crossroads is relevant to several aspects of Diana's domain. It can symbolize the paths hunters may encounter in the forest, lit only by the full moon; this symbolizes making choices "in the dark" without the light of guidance.
Diana's role as a goddess of the underworld, or at least of ushering people between life and death, caused her early on to be conflated with Hecate (and occasionally also with Proserpina). However, her role as an underworld goddess appears to pre-date strong Greek influence (though the early Greek colony of Cumae had a cult of Hekate and certainly had contacts with the Latins). A theater in her sanctuary at Lake Nemi included a pit and tunnel that would have allowed actors to easily descend on one side of the stage and ascend on the other, indicating a connection between the phases of the moon and a descent by the moon goddess into the underworld. It is likely that her underworld aspect in her original Latin worship did not have a distinct name, like Luna was for her moon aspect. This is due to a seeming reluctance or taboo by the early Latins to name underworld deities, and the fact that they believed the underworld to be silent, precluding naming. Hekate, a Greek goddess also associated with the boundary between the earth and the underworld, became attached to Diana as a name for her underworld aspect following Greek influence.
Diana was often considered to be a goddess associated with fertility and childbirth, and the protection of women during labor. This probably arose as an extension of her association with the moon, whose cycles were believed to parallel the menstrual cycle, and which was used to track the months during pregnancy. At her shrine in Aricia, worshipers left votive terracotta offerings for the goddess in the shapes of babies and wombs, and the temple there also offered care of pups and pregnant dogs. This care of infants also extended to the training of both young people and dogs, especially for hunting. In her role as a protector of childbirth, Diana was called Diana Lucina, Diana Lucifera or even Juno Lucina, because her domain overlapped with that of the goddess Juno. The title of Juno may also have had an independent origin as it applied to Diana, with the literal meaning of "helper" – Diana as Juno Lucina would be the "helper of childbirth".
According to a theory proposed by Georges Dumézil, Diana falls into a particular subset of celestial gods, referred to in histories of religion as frame gods. Such gods, while keeping the original features of celestial divinities (i.e. transcendent heavenly power and abstention from direct rule in worldly matters), did not share the fate of other celestial gods in Indoeuropean religions – that of becoming dei otiosi, or gods without practical purpose, since they did retain a particular sort of influence over the world and mankind. The celestial character of Diana is reflected in her connection with inaccessibility, virginity, light, and her preference for dwelling on high mountains and in sacred woods. Diana, therefore, reflects the heavenly world in its sovereignty, supremacy, impassibility, and indifference towards such secular matters as the fates of mortals and states. At the same time, however, she is seen as active in ensuring the succession of kings and in the preservation of humankind through the protection of childbirth. These functions are apparent in the traditional institutions and cults related to the goddess:
According to Dumezil, the forerunner of all frame gods is an Indian epic hero who was the image (avatar) of the Vedic god Dyaus. Having renounced the world, in his roles of father and king, he attained the status of an immortal being while retaining the duty of ensuring that his dynasty is preserved and that there is always a new king for each generation. The Scandinavian god Heimdallr performs an analogous function: he is born first and will die last. He too gives origin to kingship and the first king, bestowing on him regal prerogatives. Diana, although a female deity, has exactly the same functions, preserving mankind through childbirth and royal succession.
F. H. Pairault, in her essay on Diana, qualified Dumézil's theory as "impossible to verify".
Unlike the Greek gods, Roman gods were originally considered to be numina: divine powers of presence and will that did not necessarily have physical form. At the time Rome was founded, Diana and the other major Roman gods probably did not have much mythology per se, or any depictions in human form. The idea of gods as having anthropomorphic qualities and human-like personalities and actions developed later, under the influence of Greek and Etruscan religion.
By the 3rd century BCE, Diana is found listed among the twelve major gods of the Roman pantheon by the poet Ennius. Though the Capitoline Triad were the primary state gods of Rome, early Roman myth did not assign a strict hierarchy to the gods the way Greek mythology did, though the Greek hierarchy would eventually be adopted by Roman religion as well.
Once Greek influence had caused Diana to be considered identical to the Greek goddess Artemis, Diana acquired Artemis's physical description, attributes, and variants of her myths as well. Like Artemis, Diana is usually depicted in art wearing a women’s chiton, shortened in the kolpos style to facilitate mobility during hunting, with a hunting bow and quiver, and often accompanied by hunting dogs. A 1st-century BCE Roman coin (see above) depicted her with a unique, short hairstyle, and in triple form, with one form holding a bow and another holding a poppy.
When worship of Apollo was first introduced to Rome, Diana became conflated with Apollo's sister Artemis as in the earlier Greek myths, and as such she became identified as the daughter of Apollo's parents Latona and Jupiter. Though Diana was usually considered to be a virgin goddess like Artemis, later authors sometimes attributed consorts and children to her. According to Cicero and Ennius, Trivia (an epithet of Diana) and Caelus were the parents of Janus, as well as of Saturn and Ops.
According to Macrobius (who cited Nigidius Figulus and Cicero), Janus and Jana (Diana) are a pair of divinities, worshiped as the sun and moon. Janus was said to receive sacrifices before all the others because, through him, the way of access to the desired deity is made apparent.
Diana's mythology incorporated stories which were variants of earlier stories about Artemis. Possibly the most well-known of these is the myth of Actaeon. In Ovid's version of this myth, part of his poem Metamorphoses, he tells of a pool or grotto hidden in the wooded valley of Gargaphie. There, Diana, the goddess of the woods, would bathe and rest after a hunt. Actaeon, a young hunter, stumbled across the grotto and accidentally witnessed the goddess bathing without invitation. In retaliation, Diana splashed him with water from the pool, cursing him, and he transformed into a deer. His own hunting dogs caught his scent, and tore him apart.
Ovid's version of the myth of Actaeon differs from most earlier sources. Unlike earlier myths about Artemis, Actaeon is killed for an innocent mistake, glimpsing Diana bathing. An earlier variant of this myth, known as the Bath of Pallas, had the hunter intentionally spy on the bathing goddess Pallas (Athena), and earlier versions of the myth involving Artemis did not involve the bath at all.
Diana was an ancient goddess common to all Latin tribes. Therefore, many sanctuaries were dedicated to her in the lands inhabited by Latins. Her primary sanctuary was a woodland grove overlooking Lake Nemi, a body of water also known as "Diana's Mirror", where she was worshiped as Diana Nemorensis, or "Diana of the Wood". In Rome, the cult of Diana may have been almost as old as the city itself. Varro mentions her in the list of deities to whom king Titus Tatius promised to build a shrine. His list included Luna and Diana Lucina as separate entities. Another testimony to the antiquity of her cult is to be found in the lex regia of King Tullus Hostilius that condemns those guilty of incest to the sacratio to Diana. She had a temple in Rome on the Aventine Hill, according to tradition dedicated by king Servius Tullius. Its location is remarkable as the Aventine is situated outside the pomerium, i.e. original territory of the city, in order to comply with the tradition that Diana was a goddess common to all Latins and not exclusively of the Romans. Being placed on the Aventine, and thus outside the pomerium, meant that Diana's cult essentially remained a foreign one, like that of Bacchus; she was never officially transferred to Rome as Juno was after the sack of Veii.
Other known sanctuaries and temples to Diana include Colle di Corne near Tusculum, where she is referred to with the archaic Latin name of deva Cornisca and where existed a collegium of worshippers; at Évora, Portugal; Mount Algidus, also near Tusculum; at Lavinium; and at Tibur (Tivoli), where she is referred to as Diana Opifera Nemorensis. Diana was also worshiped at a sacred wood mentioned by Livy – ad compitum Anagninum (near Anagni), and on Mount Tifata in Campania.
According to Plutarch, men and women alike were worshipers of Diana and were welcomed into all of her temples. The one exception seems to have been a temple on the Vicus Patricius, which men either did not enter due to tradition, or were not allowed to enter. Plutarch related a legend that a man had attempted to assault a woman worshiping in this temple and was killed by a pack of dogs (echoing the myth of Diana and Actaeon), which resulted in a superstition against men entering the temple.
A feature common to nearly all of Diana's temples and shrines by the second century AD was the hanging up of stag antlers. Plutarch noted that the only exception to this was the temple on the Aventine Hill, in which bull horns had been hung up instead. Plutarch explains this by way of reference to a legend surrounding the sacrifice of an impressive Sabine bull by King Servius at the founding of the Aventine temple.
Diana's worship may have originated at an open-air sanctuary overlooking Lake Nemi in the Alban Hills near Aricia, where she was worshiped as Diana Nemorensis, or ("Diana of the Sylvan Glade"). According to legendary accounts, the sanctuary was founded by Orestes and Iphigenia after they fled from the Tauri. In this tradition, the Nemi sanctuary was supposedly built on the pattern of an earlier Temple of Artemis Tauropolos, and the first cult statue at Nemi was said to have been stolen from the Tauri and brought to Nemi by Orestes. Historical evidence suggests that worship of Diana at Nemi flourished from at least the 6th century BCE until the 2nd century CE. Her cult there was first attested in Latin literature by Cato the Elder, in a surviving quote by the late grammarian Priscian. By the 4th century BCE, the simple shrine at Nemi had been joined by a temple complex. The sanctuary served an important political role as it was held in common by the Latin League.
A festival to Diana, the Nemoralia, was held yearly at Nemi on the Ides of August (August 13–15). Worshipers traveled to Nemi carrying torches and garlands, and once at the lake, they left pieces of thread tied to fences and tablets inscribed with prayers. Diana's festival eventually became widely celebrated throughout Italy, which was unusual given the provincial nature of Diana's cult. The poet Statius wrote of the festival:
Statius describes the triple nature of the goddess by invoking heavenly (the stars), earthly (the grove itself) and underworld (Hecate) imagery. He also suggests by the garlanding of the dogs and polishing of the spears that no hunting was allowed during the festival.
Legend has it that Diana's high priest at Nemi, known as the Rex Nemorensis, was always an escaped slave who could only obtain the position by defeating his predecessor in a fight to the death. Sir James George Frazer wrote of this sacred grove in The Golden Bough, basing his interpretation on brief remarks in Strabo (5.3.12), Pausanias (2,27.24) and Servius' commentary on the Aeneid (6.136). The legend tells of a tree that stood in the center of the grove and was heavily guarded. No one was allowed to break off its limbs, with the exception of a runaway slave, who was allowed, if he could, to break off one of the boughs. He was then in turn granted the privilege to engage the Rex Nemorensis, the current king and priest of Diana, in a fight to the death. If the slave prevailed, he became the next king for as long as he could defeat his challengers. However, Joseph Fontenrose criticised Frazer's assumption that a rite of this sort actually occurred at the sanctuary, and no contemporary records exist that support the historical existence of the Rex Nemorensis.
Rome hoped to unify into and control the Latin tribes around Nemi, so Diana's worship was imported to Rome as a show of political solidarity. Diana soon afterwards became Hellenized, and combined with the Greek goddess Artemis, "a process which culminated with the appearance of Diana beside Apollo [the brother of Artemis] in the first lectisternium at Rome" in 399 BCE. The process of identification between the two goddesses probably began when artists who were commissioned to create new cult statues for Diana's temples outside Nemi were struck by the similar attributes between Diana and the more familiar Artemis, and sculpted Diana in a manner inspired by previous depictions of Artemis. Sibyllene influence and trade with Massilia, where similar cult statues of Artemis existed, would have completed the process.
According to Françoise Hélène Pairault's study, historical and archaeological evidence point to the fact that the characteristics given to both Diana of the Aventine Hill and Diana Nemorensis were the product of the direct or indirect influence of the cult of Artemis, which was spread by the Phoceans among the Greek towns of Campania Cuma and Capua, who in turn had passed it over to the Etruscans and the Latins by the 6th and 5th centuries BCE.
Evidence suggests that a confrontation occurred between two groups of Etruscans who fought for supremacy, those from Tarquinia, Vulci and Caere (allied with the Greeks of Capua) and those of Clusium. This is reflected in the legend of the coming of Orestes to Nemi and of the inhumation of his bones in the Roman Forum near the temple of Saturn. The cult introduced by Orestes at Nemi is apparently that of the Artemis Tauropolos. The literary amplification reveals a confused religious background: different versions of Artemis were conflated under the epithet. As far as Nemi's Diana is concerned there are two different versions, by Strabo and Servius Honoratus. Strabo's version looks to be the most authoritative as he had access to first-hand primary sources on the sanctuaries of Artemis, i.e. the priest of Artemis Artemidoros of Ephesus. The meaning of Tauropolos denotes an Asiatic goddess with lunar attributes, lady of the herds. The only possible interpretatio graeca of high antiquity concerning Diana Nemorensis could have been the one based on this ancient aspect of a deity of light, master of wildlife. Tauropolos is an ancient epithet attached to Artemis, Hecate, and even Athena. According to the legend Orestes founded Nemi together with Iphigenia. At Cuma the Sybil is the priestess of both Phoibos and Trivia. Hesiod and Stesichorus tell the story according to which after her death Iphigenia was divinised under the name of Hecate, a fact which would support the assumption that Artemis Tauropolos had a real ancient alliance with the heroine, who was her priestess in Taurid and her human paragon. This religious complex is in turn supported by the triple statue of Artemis-Hecate.
In Rome, Diana was regarded with great reverence and was a patroness of lower-class citizens, called plebeians, as well as slaves, who could receive asylum in her temples. Georg Wissowa proposed that this might be because the first slaves of the Romans were Latins of the neighboring tribes. However, the Temple of Artemis at Ephesus had the same custom of the asylum.
Worship of Diana probably spread into the city of Rome beginning around 550 BCE, during her Hellenization and combination with the Greek goddess Artemis. Diana was first worshiped along with her brother and mother, Apollo and Latona, in their temple in the Campus Martius, and later in the Temple of Apollo Palatinus.
The first major temple dedicated primarily to Diana in the vicinity of Rome was the Temple of Diana Aventina (Diana of the Aventine Hill). According to the Roman historian Livy, the construction of this temple began in the 6th century BCE and was inspired by stories of the massive Temple of Artemis at Ephesus, which was said to have been built through the combined efforts of all the cities of Asia Minor. Legend has it that Servius Tullius was impressed with this act of massive political and economic cooperation, and convinced the cities of the Latin League to work with the Romans to build their own temple to the goddess. However, there is no compelling evidence for such an early construction of the temple, and it is more likely that it was built in the 3rd century BCE, following the influence of the temple at Nemi, and probably about the same time the first temples to Vertumnus (who was associated with Diana) were built in Rome (264 BCE). The misconception that the Aventine Temple was inspired by the Ephesian Temple might originate in the fact that the cult images and statues used at the former were based heavily on those found in the latter. Whatever its initial construction date, records show that the Avantine Temple was rebuilt by Lucius Cornificius in 32 BCE. If it was still in use by the 4th century CE, the Aventine temple would have been permanently closed during the persecution of pagans in the late Roman Empire. Today, a short street named the Via del Tempio di Diana and an associated plaza, Piazza del Tempio di Diana, commemorates the site of the temple. Part of its wall is located within one of the halls of the Apuleius restaurant.
Later temple dedications often were based on the model for ritual formulas and regulations of the Temple of Diana. Roman politicians built several minor temples to Diana elsewhere in Rome to secure public support. One of these was built in the Campus Martius in 187 BCE; no Imperial period records of this temple have been found, and it is possible it was one of the temples demolished around 55 BCE in order to build a theater. Diana also had a public temple on the Quirinal Hill, the sanctuary of Diana Planciana. It was dedicated by Plancius in 55 BCE, though it is unclear which Plancius.
In their worship of Artemis, Greeks filled their temples with sculptures of the goddess created by well-known sculptors, and many were adapted for use in the worship of Diana by the Romans, beginning around the 2nd century BCE (the beginning of a period of strong Hellenistic influence on Roman religion). The earliest depictions of the Artemis of Ephesus are found on Ephesian coins from this period. By the Imperial period, small marble statues of the Ephesian Artemis were being produced in the Western region of the Mediterranean and were often bought by Roman patrons. The Romans obtained a large copy of an Ephesian Artemis statue for their temple on the Aventine Hill. Diana was usually depicted for educated Romans in her Greek guise. If she was shown accompanied by a deer, as in the Diana of Versailles, this is because Diana was the patroness of hunting. The deer may also offer a covert reference to the myth of Acteon (or Actaeon), who saw her bathing naked. Diana transformed Acteon into a stag and set his own hunting dogs to kill him.
In Campania, Diana had a major temple at Mount Tifata, near Capua. She was worshiped there as Diana Tifatina. This was one of the oldest sanctuaries in Campania. As a rural sanctuary, it included lands and estates that would have been worked by slaves following the Roman conquest of Campania, and records show that expansion and renovation projects at her temple were funded in part by other conquests by Roman military campaigns. The modern Christian church of Sant'Angelo in Formis was built on the ruins of the Tifata temple.
In the Roman provinces, Diana was widely worshiped alongside local deities. Over 100 inscriptions to Diana have been cataloged in the provinces, mainly from Gaul, Upper Germania, and Britannia. Diana was commonly invoked alongside another forest god, Silvanus, as well as other "mountain gods". In the provinces, she was occasionally conflated with local goddesses such as Abnoba, and was given high status, with Augusta and regina ("queen") being common epithets.
Diana was not only regarded as a goddess of the wilderness and the hunt, but was often worshiped as a patroness of families. She served a similar function to the hearth goddess Vesta, and was sometimes considered to be a member of the Penates, the deities most often invoked in household rituals. In this role, she was often given a name reflecting the tribe of family who worshiped her and asked for her protection. For example, in what is now Wiesbaden, Diana was worshiped as Diana Mattiaca by the Mattiaci tribe. Other family-derived named attested in the ancient literature include Diana Cariciana, Diana Valeriana, and Diana Plancia. As a house goddess, Diana often became reduced in stature compared to her official worship by the Roman state religion. In personal or family worship, Diana was brought to the level of other household spirits, and was believed to have a vested interest in the prosperity of the household and the continuation of the family. The Roman poet Horace regarded Diana as a household goddess in his Odes, and had an altar dedicated to her in his villa where household worship could be conducted. In his poetry, Horace deliberately contrasted the kinds of grand, elevated hymns to Diana on behalf of the entire Roman state, the kind of worship that would have been typical at her Aventine temple, with a more personal form of devotion.
Images of Diana and her associated myths have been found on sarcophagi of wealthy Romans. They often included scenes depicting sacrifices to the goddess, and on at least one example, the deceased man is shown joining Diana's hunt.
Since ancient times, philosophers and theologians have examined the nature of Diana in light of her worship traditions, attributes, mythology, and identification with other gods.
Diana was initially a hunting goddess and goddess of the local woodland at Nemi, but as her worship spread, she acquired attributes of other similar goddesses. As she became conflated with Artemis, she became a moon goddess, identified with the other lunar goddesses goddess Luna and Hekate. She also became the goddess of childbirth and ruled over the countryside. Catullus wrote a poem to Diana in which she has more than one alias: Latonia, Lucina, Juno, Trivia, Luna.
Along with Mars, Diana was often venerated at games held in Roman amphitheaters, and some inscriptions from the Danubian provinces show that she was conflated with Nemesis in this role, as Diana Nemesis.
Outside of Italy, Diana had important centers of worship where she was syncretised with similar local deities in Gaul, Upper Germania, and Britannia. Diana was particularly important in the region in and around the Black Forest, where she was conflated with the local goddess Abnoba and worshiped as Diana Abnoba.
Some late antique sources went even further, syncretizing many local "great goddesses" into a single "Queen of Heaven". The Platonist philosopher Apuleius, writing in the late 2nd century, depicted the goddess declaring:
"I come, Lucius, moved by your entreaties: I, mother of the universe, mistress of all the elements, first-born of the ages, highest of the gods, queen of the shades, first of those who dwell in heaven, representing in one shape all gods and goddesses. My will controls the shining heights of heaven, the health-giving sea-winds, and the mournful silences of hell; the entire world worships my single godhead in a thousand shapes, with divers rites, and under many a different name. The Phrygians, first-born of mankind, call me the Pessinuntian Mother of the gods; the native Athenians the Cecropian Minerva; the island-dwelling Cypriots Paphian Venus; the archer Cretans Dictynnan Diana; the triple-tongued Sicilians Stygian Proserpine; the ancient Eleusinians Actaean Ceres; some call me Juno, some Bellona, others Hecate, others Rhamnusia; but both races of Ethiopians, those on whom the rising and those on whom the setting sun shines, and the Egyptians who excel in ancient learning, honour me with the worship which is truly mine and call me by my true name: Queen Isis."
Later poets and historians looked to Diana's identity as a triple goddess to merge her with triads heavenly, earthly, and underworld (cthonic) goddesses. Maurus Servius Honoratus said that the same goddess was called Luna in heaven, Diana on earth, and Proserpina in hell. Michael Drayton praises the Triple Diana in poem The Man in the Moone (1606): "So these great three most powerful of the rest, Phoebe, Diana, Hecate, do tell. Her sovereignty in Heaven, in Earth and Hell".
Based on the earlier writings of Plato, the Neoplatonist philosophers of late antiquity united the various major gods of Hellenic tradition into a series of monads containing within them triads, with some creating the world, some animating it or bringing it to life, and others harmonizing it. Within this system, Proclus considered Diana to be one of the primary animating, or life-giving, deities. Proclus, citing Orphic tradition, concludes that Diana "presides over all the generation in nature, and is the midwife of physical productive principles" and that she "extends these genitals, distributing as far as to subterranean natures the prolific power of [Bacchus]." Specifically, Proclus considered the life-generating principle of the highest order, within the Intellectual realm, to be Rhea, whom he identified with Ceres. Within her divinity was produced the cause of the basic principle of life. Projecting this principle into the lower, Hypercosmic realm of reality generated a lower monad, Kore, who could therefore be understood as Ceres' "daughter". Kore embodied the "maidenly" principle of generation that, more importantly, included a principle of division – where Demeter generates life indiscriminately, Kore distributes it individually. This division results in another triad or trinity, known as the Maidenly trinity, within the monad of Kore: namely, Diana, Proserpine, and Minerva, through whom individual living beings are given life and perfected. Specifically, according to a commentary by scholar Spyridon Rangos, Diana (equated with Hecate) gives existence, Proserpine (equated with "Soul") gives form, and Minerva (equated with "Virtue") gives intellect.
In his commentary on Proclus, the 19th century Platonist scholar Thomas Taylor expanded upon the theology of the classical philosophers, further interpreting the nature and roles of the gods in light of the whole body of Neoplatonist philosophy. He cites Plato in giving a three-form aspect to her central characteristic of virginity: the undefiled, the mundane, and the anagogic. Through the first form, Diana is regarded as a "lover of virginity". Through the second, she is the guardian of virtue. Through the third, she is considered to "hate the impulses arising from generation." Through the principle of the undefiled, Taylor suggests that she is given supremacy in Proclus' triad of life-giving or animating deities, and in this role the theurgists called her Hekate. In this role, Diana is granted undefiled power (Amilieti) from the other gods. This generative power does not proceed forth from the goddess (according to a statement by the Oracle of Delphi) but rather resides with her, giving her unparalleled virtue, and in this way she can be said to embody virginity. Later commentators on Proclus have clarified that the virginity of Diana is not an absence of sexual drive, but a renunciation of sexuality. Diana embodies virginity because she generates but precedes active fertility (within Neoplatonism, an important maxim is that "every productive cause is superior to the nature of the produced effect").
Using the ancient Neoplatonists as a basis, Taylor also commented on the triadic nature of Diana and related goddesses, and the ways in which they subsist within one another, partaking unevenly in each other's powers and attributes. For example, Kore is said to embody both Diana/Hecate and Minerva, who create the virtuous or virgin power within her, but also Proserpine (her sole traditional identification), through whom the generative power of the Kore as a whole is able to proceed forth into the world, where it joins with the demiurge to produce further deities, including Bacchus and "nine azure-eyed, flower-producing daughters".
Proclus also included Artemis/Diana in a second triad of deities, along with Ceres and Juno. According to Proclus:
Proclus pointed to the conflict between Hera and Artemis in the Illiad as a representation of the two kinds of human souls. Where Hera creates the higher, more cultured, or "worthy" souls, Artemis brings light to and perfects the "less worthy" or less rational. As explained by Ragnos (2000), "The aspect of reality which Artemis and Hera share, and because of which they engage in a symbolic conflict, is the engendering of life." Hera elevates rational living beings up to intellectual rational existence, whereas Artemis's power pertains to human life as far as its physical existence as a living thing. "Artemis deals with the most elementary forms of life or the most elementary part of all life, whereas Hera operates in the most elevated forms of life or the most elevated part of all life.
Sermons and other religious documents have provided evidence for the worship of Diana during the Middle Ages. Though few details have been recorded, enough references to Diana worship during the early Christian period exist to give some indication that it may have been relatively widespread among remote and rural communities throughout Europe, and that such beliefs persisted into the Merovingian period. References to contemporary Diana worship exist from the 6th century on the Iberian peninsula and what is now southern France, though more detailed accounts of Dianic cults were given for the Low Countries, and southern Belgium in particular. Many of these were probably local goddesses, and wood nymphs or dryads, which had been conflated with Diana by Christian writers Latinizing local names and traditions.
The 6th century bishop Gregory of Tours reported meeting with a deacon named Vulfilaic (also known as Saint Wulflaicus or Walfroy the Stylite), who founded a hermitage on a hill in what is now Margut, France. On the same hill, he found "an image of Diana which the unbelieving people worshiped as a god." According to Gregory's report, worshipers would also sing chants in Diana's honor as they drank and feasted. Vulfilaic destroyed a number of smaller pagan statues in the area, but the statue of Diana was too large. After converting some of the local population to Christianity, Vulfilaic and a group of local residents attempted to pull the large statue down the mountain in order to destroy it, but failed, as it was too large to be moved. In Vulfilaic's account, after praying for a miracle, he was then able to single-handedly pull down the statue, at which point he and his group smashed it to dust with their hammers. According to Vulfilaic, this incident was quickly followed by an outbreak of pimples or sores that covered his entire body, which he attributed to demonic activity and similarly cured via what he described as a miracle. Vulfilaic would later found a church on the site, which is today known as Mont Saint-Walfroy.
Additional evidence for surviving pagan practices in the Low Countries region comes from the Vita Eligii, or "Life of Saint Eligius", written by Audoin in the 7th century. Audoin drew together the familiar admonitions of Eligius to the people of Flanders. In his sermons, he denounced "pagan customs" that the people continued to follow. In particular, he denounced several Roman gods and goddesses alongside Druidic mythological beliefs and objects:
"I denounce and contest, that you shall observe no sacrilegious pagan customs. For no cause or infirmity should you consult magicians, diviners, sorcerers or incantators. ..Do not observe auguries ... No influence attaches to the first work of the day or the [phase of the] moon. ... [Do not] make vetulas, little deer or iotticos or set tables at night or exchange New Year gifts or supply superfluous drinks... No Christian... performs solestitia or dancing or leaping or diabolical chants. No Christian should presume to invoke the name of a demon, not Neptune or Orcus or Diana or Minerva or Geniscus... No one should observe Jove's day in idleness. ... No Christian should make or render any devotion to the gods of the trivium, where three roads meet, to the fanes or the rocks, or springs or groves or corners. None should presume to hang any phylacteries from the neck of man nor beast. ..None should presume to make lustrations or incantations with herbs, or to pass cattle through a hollow tree or ditch ... No woman should presume to hang amber from her neck or call upon Minerva or other ill-starred beings in their weaving or dyeing. .. None should call the sun or moon lord or swear by them. .. No one should tell fate or fortune or horoscopes by them as those do who believe that a person must be what he was born to be."
Legends from medieval Belgium concern a natural spring which came to be known as the "Fons Remacli", a location which may have been home to late-surviving worship of Diana. Remacle was a monk appointed by Eligius to head a monastery at Solignac, and he is reported to have encountered Diana worship in the area around the river Warche. The population in this region was said to have been involved in the worship of "Diana of the Ardennes" (a syncretism of Diana and the Celtic goddess Arduinna), with effigies and "stones of Diana" used as evidence of pagan practices. Remacle believed that demonic entities were present in the spring, and had caused it to run dry. He performed and exorcism of the water source, and installed a lead pipe, which allowed the water to flow again.
Diana is the only pagan goddess mentioned by name in the New Testament (only in some Bible versions of Acts 19; many other Bibles refer to her as Artemis instead). As a result, she became associated with many folk beliefs involving goddess-like supernatural figures that Catholic clergy wished to demonize. In the Middle Ages, legends of night-time processions of spirits led by a female figure are recorded in the church records of Northern Italy, western Germany, and southern France. The spirits were said to enter houses and consume food which then miraculously re-appeared. They would sing and dance, and dispense advice regarding healing herbs and the whereabouts of lost objects. If the house was in good order, they would bring fertility and plenty. If not, they would bring curses to the family. Some women reported participating in these processions while their bodies still lay in bed. Historian Carlo Ginzburg has referred to these legendary spirit gatherings as "The Society of Diana".
Local clergy complained that women believed they were following Diana or Herodias, riding out on appointed nights to join the processions or carry out instructions from the goddess. The earliest reports of these legends appear in the writings of Regino of Prüm in the year 899, followed by many additional reports and variants of the legend in documents by Ratherius and others. By 1310, the names of the goddess figures attached to the legend were sometimes combined as Herodiana. It is likely that the clergy of this time used the identification of the procession's leader as Diana or Herodias in order to fit an older folk belief into a Biblical framework, as both are featured and demonized in the New Testament. Herodias was often conflated with her daughter Salome in legend, which also holds that, upon being presented with the severed head of John the Baptist, she was blown into the air by wind from the saint's mouth, through which she continued to wander for eternity. Diana was often conflated with Hecate, a goddess associated with the spirits of the dead and with witchcraft. These associations, and the fact that both figures are attested to in the Bible, made them a natural fit for the leader of the ghostly procession. Clergy used this identification to assert that the spirits were evil, and that the women who followed them were inspired by demons. As was typical of this time period, though pagan beliefs and practices were near totally eliminated from Europe, the clergy and other authorities still treated paganism as a real threat, in part thanks to biblical influence; much of the Bible had been written when various forms of paganism were still active if not dominant, so medieval clergy applied the same kinds of warnings and admonitions for any non-standard folk beliefs and practices they encountered. Based on analysis of church documents and parishioner confessions, it is likely that the spirit identified by the Church as Diana or Herodias was called by names of pre-Christian figures like Holda (a Germanic goddess of the winter solstice), or with names referencing her bringing of prosperity, like the Latin Abundia (meaning "plenty"), Satia (meaning "full" or "plentiful") and the Italian Richella (meaning "rich"). Some of the local titles for her, such as bonae res (meaning "good things"), are similar to late classical titles for Hecate, like bona dea. This might indicate a cultural mixture of medieval folk ideas with holdovers from earlier pagan belief systems. Whatever her true origin, by the 13th century, the leader of the legendary spirit procession had come to be firmly identified with Diana and Herodias through the influence of the Church.
In his wide-ranging, comparative study of mythology and religion, The Golden Bough, anthropologist James George Frazer drew on various lines of evidence to re-interpret the legendary rituals associated with Diana at Nemi, particularly that of the rex Nemorensis. Frazer developed his ideas in relation to J. M. W. Turner's painting, also titled The Golden Bough, depicting a dream-like vision of the woodland lake of Nemi. According to Frazer, the rex Nemorensis or king at Nemi was the incarnation of a dying and reviving god, a solar deity who participated in a mystical marriage to a goddess. He died at the harvest and was reincarnated in the spring. Frazer claimed that this motif of death and rebirth is central to nearly all of the world's religions and mythologies. In Frazer's theory, Diana functioned as a goddess of fertility and childbirth, who, assisted by the sacred king, ritually returned life to the land in spring. The king in this scheme served not only as a high priest but as a god of the grove. Frazer identifies this figure with Virbius, of which little is known, but also with Jupiter via an association with sacred oak trees. Frazer argued furthermore that Jupiter and Juno were simply duplicate names of Jana and Janus; that is, Diana and Dianus, all of whom had identical functions and origins.
Frazer's speculatively reconstructed folklore of Diana's origins and the nature of her cult at Nemi were not well received even by his contemporaries. Godfrey Lienhardt noted that even during Frazer's lifetime, other anthropologists had "for the most part distanced themselves from his theories and opinions", and that the lasting influence of The Golden Bough and Frazer's wider body of work "has been in the literary rather than the academic world." Robert Ackerman wrote that, for anthropologists, Frazer is "an embarrassment" for being "the most famous of them all" and that most distance themselves from his work. While The Golden Bough achieved wide "popular appeal" and exerted a "disproportionate" influence "on so many [20th century] creative writers", Frazer's ideas played "a much smaller part" in the history of academic social anthropology.
Folk legends like the Society of Diana, which linked the goddess to forbidden gatherings of women with spirits, may have influenced later works of folklore. One of these is Charles Godfrey Leland's Aradia, or the Gospel of the Witches, which prominently featured Diana at the center of an Italian witch-cult. In Leland's interpretation of supposed Italian folk witchcraft, Diana is considered Queen of the Witches. In this belief system, Diana is said to have created the world of her own being having in herself the seeds of all creation yet to come. It was said that out of herself she divided the darkness and the light, keeping for herself the darkness of creation and creating her brother Lucifer. Diana was believed to have loved and ruled with her brother, and with him bore a daughter, Aradia (a name likely derived from Herodias), who leads and teaches the witches on earth.
Leland's claim that Aradia represented an authentic tradition from an underground witch-cult, which had secretly worshiped Diana since ancient times has been dismissed by most scholars of folklore, religion, and medieval history. After the 1921 publication of Margaret Murray's The Witch-cult in Western Europe, which hypothesized that the European witch trials were actually a persecution of a pagan religious survival, American sensationalist author Theda Kenyon's 1929 book Witches Still Live connected Murray's thesis with the witchcraft religion in Aradia. Arguments against Murray's thesis would eventually include arguments against Leland. Witchcraft scholar Jeffrey Russell devoted some of his 1980 book A History of Witchcraft: Sorcerers, Heretics and Pagans to arguing against the claims Leland presented in Aradia. Historian Elliot Rose's A Razor for a Goat dismissed Aradia as a collection of incantations unsuccessfully attempting to portray a religion. In his book Triumph of the Moon, historian Ronald Hutton doubted not only of the existence of the religion that Aradia claimed to represent, and that the traditions Leland presented were unlike anything found in actual medieval literature, but also of the existence of Leland's sources, arguing that it is more likely that Leland created the entire story than that Leland could be so easily "duped". Religious scholar Chas S. Clifton took exception to Hutton's position, writing that it amounted to an accusation of "serious literary fraud" made by an "argument from absence".
Building on the work of Frazer, Murray, and others, some 20th and 21st century authors have attempted to identify links between Diana and more localized deities. R. Lowe Thompson, for example, in his 2013 book The History of the Devil, speculated that Diana may have been linked as an occasional "spouse" to the Gaulish horned god Cernunnos. Thompson suggested that Diana in her role as wild goddess of the hunt would have made a fitting consort for Cernunnos in Western Europe, and further noted the link between Diana as Proserpina with Pluto, the Greek god associated with the riches of the earth who served a similar role to the Gaulish Cernunnos.
Because Leland's claims about an Italian witch-cult are questionable, the first verifiable worship of Diana in the modern age was probably begun by Wicca. The earliest known practitioners of Neopagan witchcraft were members of a tradition begun by Gerald Gardner. Published versions of the devotional materials used by Gardner's group, dated to 1949, are heavily focused on the worship of Aradia, the daughter of Diana in Leland's folklore. Diana herself was recognized as an aspect of a single "great goddess" in the tradition of Apuleius, as described in the Wiccan Charge of the Goddess (itself adapted from Leland's text). Some later Wiccans, such as Scott Cunningham, would replace Aradia with Diana as the central focus of worship.
In the early 1960s, Victor Henry Anderson founded the Feri Tradition, a form of Wicca that draws from both Charles Leland's folklore and the Gardnerian tradition. Anderson claimed that he had first been initiated into a witchcraft tradition as a child in 1926, and that he had been told the name of the goddess worshiped by witches was Tana. The name Tana originated in Leland's Aradia, where he claimed it was an old Etruscan name for Diana. The Feri Tradition founded by Anderson continues to recognize Tana/Diana as an aspect of the Star Goddess related to the element of fire, and representing "the fiery womb that gives birth to and transforms all matter." (In Aradia, Diana is also credited as the creatrix of the material world and Queen of Faeries).
A few Wiccan traditions would elevate Diana to a more prominent position of worship, and there are two distinct modern branches of Wicca focused primarily on Diana. The first, founded during the early 1970s in the United States by Morgan McFarland and Mark Roberts, has a feminist theology and only occasionally accepts male participants, and leadership is limited to female priestesses. McFarland Dianic Wiccans base their tradition primarily on the work of Robert Graves and his book The White Goddess, and were inspired by references to the existence of medieval European "Dianic cults" in Margaret Murray's book The Witch-Cult in Western Europe. The second Dianic tradition, founded by Zsuzsanna Budapest in the mid 1970s, is characterized by an exclusive focus on the feminine aspect of the divine, and as a result is exclusively female. This tradition combines elements from British Traditional Wicca, Italian folk-magic based on the work of Charles Leland, feminist values, and healing practices drawn from a variety of different cultures.
A third Neopagan tradition heavily inspired by the worship of Diana through the lens of Italian folklore is Stregheria, founded in the 1980s. It centers around a pair of deities regarded as divine lovers, who are known by several variant names including Diana and Dianus, alternately given as Tana and Tanus or Jana and Janus (the later two deity names were mentioned by James Frazer in The Golden Bough as later corruptions of Diana and Dianus, which themselves were alternate and possibly older names for Juno and Jupiter). The tradition was founded by author Raven Grimassi, and influenced by Italian folktales he was told by his mother. One such folktale describes the moon being impregnated by her lover the morning star, a parallel to Leland's mythology of Diana and her lover Lucifer.
Diana was also a subject of worship in certain Feraferian rites, particularly those surrounding the autumnal equinox, beginning in 1967.
Both the Romanian words for "fairy" Zână and Sânziană, the Leonese and Portuguese word for "water nymph" xana, and the Spanish word for "shooting target" and "morning call" (diana) seem to come from the name of Diana.
Since the Renaissance, Diana's myths have often been represented in the visual and dramatic arts, including the opera L'arbore di Diana. In the 16th century, Diana's image figured prominently at the châteaus of Fontainebleau, Chenonceau, and at Anet, in deference to Diane de Poitiers, mistress of Henri of France. At Versailles she was incorporated into the Olympian iconography with which Louis XIV, the Apollo-like "Sun King" liked to surround himself. Diana is also a character in the 1876 Léo Delibes ballet Sylvia. The plot deals with Sylvia, one of Diana's nymphs and sworn to chastity, and Diana's assault on Sylvia's affections for the shepherd Amyntas.
Diana has been one of the most popular themes in art. Painters like Titian, Peter Paul Rubens, François Boucher, Nicolas Poussin and made use of her myth as a major theme. Most depictions of Diana in art featured the stories of Diana and Actaeon, or Callisto, or depicted her resting after hunting. Some famous work of arts with a Diana theme are:
There are many statues of Diana the Huntress in Yambol, Bulgaria. | [
{
"paragraph_id": 0,
"text": "Diana is a goddess in Roman and Hellenistic religion, primarily considered a patroness of the countryside and nature, hunters, wildlife, childbirth, crossroads, the night, and the Moon. She is equated with the Greek goddess Artemis, and absorbed much of Artemis' mythology early in Roman history, including a birth on the island of Delos to parents Jupiter and Latona, and a twin brother, Apollo, though she had an independent origin in Italy.",
"title": ""
},
{
"paragraph_id": 1,
"text": "Diana is considered a virgin goddess and protector of childbirth. Historically, Diana made up a triad with two other Roman deities: Egeria the water nymph, her servant and assistant midwife; and Virbius, the woodland god.",
"title": ""
},
{
"paragraph_id": 2,
"text": "Diana is revered in modern neopagan religions including Roman neopaganism, Stregheria, and Wicca. In the ancient, medieval, and modern periods, Diana has been considered a triple deity, merged with a goddess of the moon (Luna/Selene) and the underworld (usually Hecate).",
"title": ""
},
{
"paragraph_id": 3,
"text": "The name Dīāna probably derives from Latin dīus ('godly'), ultimately from Proto-Italic *dīwī, meaning 'divine, heavenly'. It stems from Proto-Indo-European *diwyós ('divine, heavenly'), formed with the stem *dyew- ('daylight sky') attached the thematic suffix -yós. Cognates appear in Myceanean Greek di-wi-ja, in Ancient Greek dîos (δῖος; 'belonging to heaven, godlike'), and in Sanskrit divyá ('heavenly' or 'celestial').",
"title": "Etymology"
},
{
"paragraph_id": 4,
"text": "The ancient Latin writers Varro and Cicero considered the etymology of Dīāna as allied to that of dies and connected to the shine of the Moon, noting that one of her titles is Diana Lucifera (\"light-bearer\").",
"title": "Etymology"
},
{
"paragraph_id": 5,
"text": "... people regard Diana and the moon as one and the same. ... the moon (luna) is so called from the verb to shine (lucere). Lucina is identified with it, which is why in our country they invoke Juno Lucina in childbirth, just as the Greeks call on Diana the Light-bearer. Diana also has the name Omnivaga (\"wandering everywhere\"), not because of her hunting but because she is numbered as one of the seven planets; her name Diana derives from the fact that she turns darkness into daylight (dies). She is invoked at childbirth because children are born occasionally after seven, or usually after nine, lunar revolutions ...",
"title": "Etymology"
},
{
"paragraph_id": 6,
"text": "The persona of Diana is complex, and contains a number of archaic features. Diana was originally considered to be a goddess of the wilderness and of the hunt, a central sport in both Roman and Greek culture. Early Roman inscriptions to Diana celebrated her primarily as a huntress and patron of hunters. Later, in the Hellenistic period, Diana came to be equally or more revered as a goddess not of the wild woodland but of the \"tame\" countryside, or villa rustica, the idealization of which was common in Greek thought and poetry. This dual role as goddess of both civilization and the wild, and therefore the civilized countryside, first applied to the Greek goddess Artemis (for example, in the 3rd century BCE poetry of Anacreon).",
"title": "Description"
},
{
"paragraph_id": 7,
"text": "By the 3rd century CE, after Greek influence had a profound impact on Roman religion, Diana had been almost fully combined with Artemis and took on many of her attributes, both in her spiritual domains and in the description of her appearance. The Roman poet Nemesianus wrote a typical description of Diana: She carried a bow and a quiver full of golden arrows, wore a golden cloak, purple half-boots, and a belt with a jeweled buckle to hold her tunic together, and wore her hair gathered in a ribbon. By the 5th century CE, almost a millennia after her cult's entry into Rome, the philosopher Proclus could still characterize Diana as \"the inspective guardian of every thing rural, [who] represses every thing rustic and uncultivated.\"",
"title": "Description"
},
{
"paragraph_id": 8,
"text": "Diana was often considered an aspect of a triple goddess, known as Diana triformis: Diana, Luna, and Hecate. According to historian C.M. Green, \"these were neither different goddesses nor an amalgamation of different goddesses. They were Diana...Diana as huntress, Diana as the moon, Diana of the underworld.\" At her sacred grove on the shores of Lake Nemi, Diana was venerated as a triple goddess beginning in the late 6th century BCE.",
"title": "Description"
},
{
"paragraph_id": 9,
"text": "Andreas Alföldi interpreted an image on a late Republican coin as the Latin Diana \"conceived as a threefold unity of the divine huntress, the Moon goddess and the goddess of the nether world, Hekate\". This coin, minted by P. Accoleius Lariscolus in 43 BCE, has been acknowledged as representing an archaic statue of Diana Nemorensis. It represents Artemis with the bow at one extremity, Luna-Selene with flowers at the other and a central deity not immediately identifiable, all united by a horizontal bar. The iconographical analysis allows the dating of this image to the 6th century at which time there are Etruscan models. The coin shows that the triple goddess cult image still stood in the lucus of Nemi in 43 BCE. Lake Nemi was called Triviae lacus by Virgil (Aeneid 7.516), while Horace called Diana montium custos nemoremque virgo (\"keeper of the mountains and virgin of Nemi\") and diva triformis (\"three-form goddess\").",
"title": "Description"
},
{
"paragraph_id": 10,
"text": "Two heads found in the sanctuary and the Roman theatre at Nemi, which have a hollow on their back, lend support to this interpretation of an archaic triple Diana.",
"title": "Description"
},
{
"paragraph_id": 11,
"text": "The earliest epithet of Diana was Trivia, and she was addressed with that title by Virgil, Catullus, and many others. \"Trivia\" comes from the Latin trivium, \"triple way\", and refers to Diana's guardianship over roadways, particularly Y-junctions or three-way crossroads. This role carried a somewhat dark and dangerous connotation, as it metaphorically pointed the way to the underworld. In the 1st-century CE play Medea, Seneca's titular sorceress calls on Trivia to cast a magic spell. She evokes the triple goddess of Diana, Selene, and Hecate, and specifies that she requires the powers of the latter. The 1st century poet Horace similarly wrote of a magic incantation invoking the power of both Diana and Proserpina. The symbol of the crossroads is relevant to several aspects of Diana's domain. It can symbolize the paths hunters may encounter in the forest, lit only by the full moon; this symbolizes making choices \"in the dark\" without the light of guidance.",
"title": "Description"
},
{
"paragraph_id": 12,
"text": "Diana's role as a goddess of the underworld, or at least of ushering people between life and death, caused her early on to be conflated with Hecate (and occasionally also with Proserpina). However, her role as an underworld goddess appears to pre-date strong Greek influence (though the early Greek colony of Cumae had a cult of Hekate and certainly had contacts with the Latins). A theater in her sanctuary at Lake Nemi included a pit and tunnel that would have allowed actors to easily descend on one side of the stage and ascend on the other, indicating a connection between the phases of the moon and a descent by the moon goddess into the underworld. It is likely that her underworld aspect in her original Latin worship did not have a distinct name, like Luna was for her moon aspect. This is due to a seeming reluctance or taboo by the early Latins to name underworld deities, and the fact that they believed the underworld to be silent, precluding naming. Hekate, a Greek goddess also associated with the boundary between the earth and the underworld, became attached to Diana as a name for her underworld aspect following Greek influence.",
"title": "Description"
},
{
"paragraph_id": 13,
"text": "Diana was often considered to be a goddess associated with fertility and childbirth, and the protection of women during labor. This probably arose as an extension of her association with the moon, whose cycles were believed to parallel the menstrual cycle, and which was used to track the months during pregnancy. At her shrine in Aricia, worshipers left votive terracotta offerings for the goddess in the shapes of babies and wombs, and the temple there also offered care of pups and pregnant dogs. This care of infants also extended to the training of both young people and dogs, especially for hunting. In her role as a protector of childbirth, Diana was called Diana Lucina, Diana Lucifera or even Juno Lucina, because her domain overlapped with that of the goddess Juno. The title of Juno may also have had an independent origin as it applied to Diana, with the literal meaning of \"helper\" – Diana as Juno Lucina would be the \"helper of childbirth\".",
"title": "Description"
},
{
"paragraph_id": 14,
"text": "According to a theory proposed by Georges Dumézil, Diana falls into a particular subset of celestial gods, referred to in histories of religion as frame gods. Such gods, while keeping the original features of celestial divinities (i.e. transcendent heavenly power and abstention from direct rule in worldly matters), did not share the fate of other celestial gods in Indoeuropean religions – that of becoming dei otiosi, or gods without practical purpose, since they did retain a particular sort of influence over the world and mankind. The celestial character of Diana is reflected in her connection with inaccessibility, virginity, light, and her preference for dwelling on high mountains and in sacred woods. Diana, therefore, reflects the heavenly world in its sovereignty, supremacy, impassibility, and indifference towards such secular matters as the fates of mortals and states. At the same time, however, she is seen as active in ensuring the succession of kings and in the preservation of humankind through the protection of childbirth. These functions are apparent in the traditional institutions and cults related to the goddess:",
"title": "Description"
},
{
"paragraph_id": 15,
"text": "According to Dumezil, the forerunner of all frame gods is an Indian epic hero who was the image (avatar) of the Vedic god Dyaus. Having renounced the world, in his roles of father and king, he attained the status of an immortal being while retaining the duty of ensuring that his dynasty is preserved and that there is always a new king for each generation. The Scandinavian god Heimdallr performs an analogous function: he is born first and will die last. He too gives origin to kingship and the first king, bestowing on him regal prerogatives. Diana, although a female deity, has exactly the same functions, preserving mankind through childbirth and royal succession.",
"title": "Description"
},
{
"paragraph_id": 16,
"text": "F. H. Pairault, in her essay on Diana, qualified Dumézil's theory as \"impossible to verify\".",
"title": "Description"
},
{
"paragraph_id": 17,
"text": "Unlike the Greek gods, Roman gods were originally considered to be numina: divine powers of presence and will that did not necessarily have physical form. At the time Rome was founded, Diana and the other major Roman gods probably did not have much mythology per se, or any depictions in human form. The idea of gods as having anthropomorphic qualities and human-like personalities and actions developed later, under the influence of Greek and Etruscan religion.",
"title": "Mythology"
},
{
"paragraph_id": 18,
"text": "By the 3rd century BCE, Diana is found listed among the twelve major gods of the Roman pantheon by the poet Ennius. Though the Capitoline Triad were the primary state gods of Rome, early Roman myth did not assign a strict hierarchy to the gods the way Greek mythology did, though the Greek hierarchy would eventually be adopted by Roman religion as well.",
"title": "Mythology"
},
{
"paragraph_id": 19,
"text": "Once Greek influence had caused Diana to be considered identical to the Greek goddess Artemis, Diana acquired Artemis's physical description, attributes, and variants of her myths as well. Like Artemis, Diana is usually depicted in art wearing a women’s chiton, shortened in the kolpos style to facilitate mobility during hunting, with a hunting bow and quiver, and often accompanied by hunting dogs. A 1st-century BCE Roman coin (see above) depicted her with a unique, short hairstyle, and in triple form, with one form holding a bow and another holding a poppy.",
"title": "Mythology"
},
{
"paragraph_id": 20,
"text": "When worship of Apollo was first introduced to Rome, Diana became conflated with Apollo's sister Artemis as in the earlier Greek myths, and as such she became identified as the daughter of Apollo's parents Latona and Jupiter. Though Diana was usually considered to be a virgin goddess like Artemis, later authors sometimes attributed consorts and children to her. According to Cicero and Ennius, Trivia (an epithet of Diana) and Caelus were the parents of Janus, as well as of Saturn and Ops.",
"title": "Mythology"
},
{
"paragraph_id": 21,
"text": "According to Macrobius (who cited Nigidius Figulus and Cicero), Janus and Jana (Diana) are a pair of divinities, worshiped as the sun and moon. Janus was said to receive sacrifices before all the others because, through him, the way of access to the desired deity is made apparent.",
"title": "Mythology"
},
{
"paragraph_id": 22,
"text": "Diana's mythology incorporated stories which were variants of earlier stories about Artemis. Possibly the most well-known of these is the myth of Actaeon. In Ovid's version of this myth, part of his poem Metamorphoses, he tells of a pool or grotto hidden in the wooded valley of Gargaphie. There, Diana, the goddess of the woods, would bathe and rest after a hunt. Actaeon, a young hunter, stumbled across the grotto and accidentally witnessed the goddess bathing without invitation. In retaliation, Diana splashed him with water from the pool, cursing him, and he transformed into a deer. His own hunting dogs caught his scent, and tore him apart.",
"title": "Mythology"
},
{
"paragraph_id": 23,
"text": "Ovid's version of the myth of Actaeon differs from most earlier sources. Unlike earlier myths about Artemis, Actaeon is killed for an innocent mistake, glimpsing Diana bathing. An earlier variant of this myth, known as the Bath of Pallas, had the hunter intentionally spy on the bathing goddess Pallas (Athena), and earlier versions of the myth involving Artemis did not involve the bath at all.",
"title": "Mythology"
},
{
"paragraph_id": 24,
"text": "Diana was an ancient goddess common to all Latin tribes. Therefore, many sanctuaries were dedicated to her in the lands inhabited by Latins. Her primary sanctuary was a woodland grove overlooking Lake Nemi, a body of water also known as \"Diana's Mirror\", where she was worshiped as Diana Nemorensis, or \"Diana of the Wood\". In Rome, the cult of Diana may have been almost as old as the city itself. Varro mentions her in the list of deities to whom king Titus Tatius promised to build a shrine. His list included Luna and Diana Lucina as separate entities. Another testimony to the antiquity of her cult is to be found in the lex regia of King Tullus Hostilius that condemns those guilty of incest to the sacratio to Diana. She had a temple in Rome on the Aventine Hill, according to tradition dedicated by king Servius Tullius. Its location is remarkable as the Aventine is situated outside the pomerium, i.e. original territory of the city, in order to comply with the tradition that Diana was a goddess common to all Latins and not exclusively of the Romans. Being placed on the Aventine, and thus outside the pomerium, meant that Diana's cult essentially remained a foreign one, like that of Bacchus; she was never officially transferred to Rome as Juno was after the sack of Veii.",
"title": "Worship in the classical period"
},
{
"paragraph_id": 25,
"text": "Other known sanctuaries and temples to Diana include Colle di Corne near Tusculum, where she is referred to with the archaic Latin name of deva Cornisca and where existed a collegium of worshippers; at Évora, Portugal; Mount Algidus, also near Tusculum; at Lavinium; and at Tibur (Tivoli), where she is referred to as Diana Opifera Nemorensis. Diana was also worshiped at a sacred wood mentioned by Livy – ad compitum Anagninum (near Anagni), and on Mount Tifata in Campania.",
"title": "Worship in the classical period"
},
{
"paragraph_id": 26,
"text": "According to Plutarch, men and women alike were worshipers of Diana and were welcomed into all of her temples. The one exception seems to have been a temple on the Vicus Patricius, which men either did not enter due to tradition, or were not allowed to enter. Plutarch related a legend that a man had attempted to assault a woman worshiping in this temple and was killed by a pack of dogs (echoing the myth of Diana and Actaeon), which resulted in a superstition against men entering the temple.",
"title": "Worship in the classical period"
},
{
"paragraph_id": 27,
"text": "A feature common to nearly all of Diana's temples and shrines by the second century AD was the hanging up of stag antlers. Plutarch noted that the only exception to this was the temple on the Aventine Hill, in which bull horns had been hung up instead. Plutarch explains this by way of reference to a legend surrounding the sacrifice of an impressive Sabine bull by King Servius at the founding of the Aventine temple.",
"title": "Worship in the classical period"
},
{
"paragraph_id": 28,
"text": "Diana's worship may have originated at an open-air sanctuary overlooking Lake Nemi in the Alban Hills near Aricia, where she was worshiped as Diana Nemorensis, or (\"Diana of the Sylvan Glade\"). According to legendary accounts, the sanctuary was founded by Orestes and Iphigenia after they fled from the Tauri. In this tradition, the Nemi sanctuary was supposedly built on the pattern of an earlier Temple of Artemis Tauropolos, and the first cult statue at Nemi was said to have been stolen from the Tauri and brought to Nemi by Orestes. Historical evidence suggests that worship of Diana at Nemi flourished from at least the 6th century BCE until the 2nd century CE. Her cult there was first attested in Latin literature by Cato the Elder, in a surviving quote by the late grammarian Priscian. By the 4th century BCE, the simple shrine at Nemi had been joined by a temple complex. The sanctuary served an important political role as it was held in common by the Latin League.",
"title": "Worship in the classical period"
},
{
"paragraph_id": 29,
"text": "A festival to Diana, the Nemoralia, was held yearly at Nemi on the Ides of August (August 13–15). Worshipers traveled to Nemi carrying torches and garlands, and once at the lake, they left pieces of thread tied to fences and tablets inscribed with prayers. Diana's festival eventually became widely celebrated throughout Italy, which was unusual given the provincial nature of Diana's cult. The poet Statius wrote of the festival:",
"title": "Worship in the classical period"
},
{
"paragraph_id": 30,
"text": "Statius describes the triple nature of the goddess by invoking heavenly (the stars), earthly (the grove itself) and underworld (Hecate) imagery. He also suggests by the garlanding of the dogs and polishing of the spears that no hunting was allowed during the festival.",
"title": "Worship in the classical period"
},
{
"paragraph_id": 31,
"text": "Legend has it that Diana's high priest at Nemi, known as the Rex Nemorensis, was always an escaped slave who could only obtain the position by defeating his predecessor in a fight to the death. Sir James George Frazer wrote of this sacred grove in The Golden Bough, basing his interpretation on brief remarks in Strabo (5.3.12), Pausanias (2,27.24) and Servius' commentary on the Aeneid (6.136). The legend tells of a tree that stood in the center of the grove and was heavily guarded. No one was allowed to break off its limbs, with the exception of a runaway slave, who was allowed, if he could, to break off one of the boughs. He was then in turn granted the privilege to engage the Rex Nemorensis, the current king and priest of Diana, in a fight to the death. If the slave prevailed, he became the next king for as long as he could defeat his challengers. However, Joseph Fontenrose criticised Frazer's assumption that a rite of this sort actually occurred at the sanctuary, and no contemporary records exist that support the historical existence of the Rex Nemorensis.",
"title": "Worship in the classical period"
},
{
"paragraph_id": 32,
"text": "Rome hoped to unify into and control the Latin tribes around Nemi, so Diana's worship was imported to Rome as a show of political solidarity. Diana soon afterwards became Hellenized, and combined with the Greek goddess Artemis, \"a process which culminated with the appearance of Diana beside Apollo [the brother of Artemis] in the first lectisternium at Rome\" in 399 BCE. The process of identification between the two goddesses probably began when artists who were commissioned to create new cult statues for Diana's temples outside Nemi were struck by the similar attributes between Diana and the more familiar Artemis, and sculpted Diana in a manner inspired by previous depictions of Artemis. Sibyllene influence and trade with Massilia, where similar cult statues of Artemis existed, would have completed the process.",
"title": "Worship in the classical period"
},
{
"paragraph_id": 33,
"text": "According to Françoise Hélène Pairault's study, historical and archaeological evidence point to the fact that the characteristics given to both Diana of the Aventine Hill and Diana Nemorensis were the product of the direct or indirect influence of the cult of Artemis, which was spread by the Phoceans among the Greek towns of Campania Cuma and Capua, who in turn had passed it over to the Etruscans and the Latins by the 6th and 5th centuries BCE.",
"title": "Worship in the classical period"
},
{
"paragraph_id": 34,
"text": "Evidence suggests that a confrontation occurred between two groups of Etruscans who fought for supremacy, those from Tarquinia, Vulci and Caere (allied with the Greeks of Capua) and those of Clusium. This is reflected in the legend of the coming of Orestes to Nemi and of the inhumation of his bones in the Roman Forum near the temple of Saturn. The cult introduced by Orestes at Nemi is apparently that of the Artemis Tauropolos. The literary amplification reveals a confused religious background: different versions of Artemis were conflated under the epithet. As far as Nemi's Diana is concerned there are two different versions, by Strabo and Servius Honoratus. Strabo's version looks to be the most authoritative as he had access to first-hand primary sources on the sanctuaries of Artemis, i.e. the priest of Artemis Artemidoros of Ephesus. The meaning of Tauropolos denotes an Asiatic goddess with lunar attributes, lady of the herds. The only possible interpretatio graeca of high antiquity concerning Diana Nemorensis could have been the one based on this ancient aspect of a deity of light, master of wildlife. Tauropolos is an ancient epithet attached to Artemis, Hecate, and even Athena. According to the legend Orestes founded Nemi together with Iphigenia. At Cuma the Sybil is the priestess of both Phoibos and Trivia. Hesiod and Stesichorus tell the story according to which after her death Iphigenia was divinised under the name of Hecate, a fact which would support the assumption that Artemis Tauropolos had a real ancient alliance with the heroine, who was her priestess in Taurid and her human paragon. This religious complex is in turn supported by the triple statue of Artemis-Hecate.",
"title": "Worship in the classical period"
},
{
"paragraph_id": 35,
"text": "In Rome, Diana was regarded with great reverence and was a patroness of lower-class citizens, called plebeians, as well as slaves, who could receive asylum in her temples. Georg Wissowa proposed that this might be because the first slaves of the Romans were Latins of the neighboring tribes. However, the Temple of Artemis at Ephesus had the same custom of the asylum.",
"title": "Worship in the classical period"
},
{
"paragraph_id": 36,
"text": "Worship of Diana probably spread into the city of Rome beginning around 550 BCE, during her Hellenization and combination with the Greek goddess Artemis. Diana was first worshiped along with her brother and mother, Apollo and Latona, in their temple in the Campus Martius, and later in the Temple of Apollo Palatinus.",
"title": "Worship in the classical period"
},
{
"paragraph_id": 37,
"text": "The first major temple dedicated primarily to Diana in the vicinity of Rome was the Temple of Diana Aventina (Diana of the Aventine Hill). According to the Roman historian Livy, the construction of this temple began in the 6th century BCE and was inspired by stories of the massive Temple of Artemis at Ephesus, which was said to have been built through the combined efforts of all the cities of Asia Minor. Legend has it that Servius Tullius was impressed with this act of massive political and economic cooperation, and convinced the cities of the Latin League to work with the Romans to build their own temple to the goddess. However, there is no compelling evidence for such an early construction of the temple, and it is more likely that it was built in the 3rd century BCE, following the influence of the temple at Nemi, and probably about the same time the first temples to Vertumnus (who was associated with Diana) were built in Rome (264 BCE). The misconception that the Aventine Temple was inspired by the Ephesian Temple might originate in the fact that the cult images and statues used at the former were based heavily on those found in the latter. Whatever its initial construction date, records show that the Avantine Temple was rebuilt by Lucius Cornificius in 32 BCE. If it was still in use by the 4th century CE, the Aventine temple would have been permanently closed during the persecution of pagans in the late Roman Empire. Today, a short street named the Via del Tempio di Diana and an associated plaza, Piazza del Tempio di Diana, commemorates the site of the temple. Part of its wall is located within one of the halls of the Apuleius restaurant.",
"title": "Worship in the classical period"
},
{
"paragraph_id": 38,
"text": "Later temple dedications often were based on the model for ritual formulas and regulations of the Temple of Diana. Roman politicians built several minor temples to Diana elsewhere in Rome to secure public support. One of these was built in the Campus Martius in 187 BCE; no Imperial period records of this temple have been found, and it is possible it was one of the temples demolished around 55 BCE in order to build a theater. Diana also had a public temple on the Quirinal Hill, the sanctuary of Diana Planciana. It was dedicated by Plancius in 55 BCE, though it is unclear which Plancius.",
"title": "Worship in the classical period"
},
{
"paragraph_id": 39,
"text": "In their worship of Artemis, Greeks filled their temples with sculptures of the goddess created by well-known sculptors, and many were adapted for use in the worship of Diana by the Romans, beginning around the 2nd century BCE (the beginning of a period of strong Hellenistic influence on Roman religion). The earliest depictions of the Artemis of Ephesus are found on Ephesian coins from this period. By the Imperial period, small marble statues of the Ephesian Artemis were being produced in the Western region of the Mediterranean and were often bought by Roman patrons. The Romans obtained a large copy of an Ephesian Artemis statue for their temple on the Aventine Hill. Diana was usually depicted for educated Romans in her Greek guise. If she was shown accompanied by a deer, as in the Diana of Versailles, this is because Diana was the patroness of hunting. The deer may also offer a covert reference to the myth of Acteon (or Actaeon), who saw her bathing naked. Diana transformed Acteon into a stag and set his own hunting dogs to kill him.",
"title": "Worship in the classical period"
},
{
"paragraph_id": 40,
"text": "In Campania, Diana had a major temple at Mount Tifata, near Capua. She was worshiped there as Diana Tifatina. This was one of the oldest sanctuaries in Campania. As a rural sanctuary, it included lands and estates that would have been worked by slaves following the Roman conquest of Campania, and records show that expansion and renovation projects at her temple were funded in part by other conquests by Roman military campaigns. The modern Christian church of Sant'Angelo in Formis was built on the ruins of the Tifata temple.",
"title": "Worship in the classical period"
},
{
"paragraph_id": 41,
"text": "In the Roman provinces, Diana was widely worshiped alongside local deities. Over 100 inscriptions to Diana have been cataloged in the provinces, mainly from Gaul, Upper Germania, and Britannia. Diana was commonly invoked alongside another forest god, Silvanus, as well as other \"mountain gods\". In the provinces, she was occasionally conflated with local goddesses such as Abnoba, and was given high status, with Augusta and regina (\"queen\") being common epithets.",
"title": "Worship in the classical period"
},
{
"paragraph_id": 42,
"text": "Diana was not only regarded as a goddess of the wilderness and the hunt, but was often worshiped as a patroness of families. She served a similar function to the hearth goddess Vesta, and was sometimes considered to be a member of the Penates, the deities most often invoked in household rituals. In this role, she was often given a name reflecting the tribe of family who worshiped her and asked for her protection. For example, in what is now Wiesbaden, Diana was worshiped as Diana Mattiaca by the Mattiaci tribe. Other family-derived named attested in the ancient literature include Diana Cariciana, Diana Valeriana, and Diana Plancia. As a house goddess, Diana often became reduced in stature compared to her official worship by the Roman state religion. In personal or family worship, Diana was brought to the level of other household spirits, and was believed to have a vested interest in the prosperity of the household and the continuation of the family. The Roman poet Horace regarded Diana as a household goddess in his Odes, and had an altar dedicated to her in his villa where household worship could be conducted. In his poetry, Horace deliberately contrasted the kinds of grand, elevated hymns to Diana on behalf of the entire Roman state, the kind of worship that would have been typical at her Aventine temple, with a more personal form of devotion.",
"title": "Worship in the classical period"
},
{
"paragraph_id": 43,
"text": "Images of Diana and her associated myths have been found on sarcophagi of wealthy Romans. They often included scenes depicting sacrifices to the goddess, and on at least one example, the deceased man is shown joining Diana's hunt.",
"title": "Worship in the classical period"
},
{
"paragraph_id": 44,
"text": "Since ancient times, philosophers and theologians have examined the nature of Diana in light of her worship traditions, attributes, mythology, and identification with other gods.",
"title": "Theology"
},
{
"paragraph_id": 45,
"text": "Diana was initially a hunting goddess and goddess of the local woodland at Nemi, but as her worship spread, she acquired attributes of other similar goddesses. As she became conflated with Artemis, she became a moon goddess, identified with the other lunar goddesses goddess Luna and Hekate. She also became the goddess of childbirth and ruled over the countryside. Catullus wrote a poem to Diana in which she has more than one alias: Latonia, Lucina, Juno, Trivia, Luna.",
"title": "Theology"
},
{
"paragraph_id": 46,
"text": "Along with Mars, Diana was often venerated at games held in Roman amphitheaters, and some inscriptions from the Danubian provinces show that she was conflated with Nemesis in this role, as Diana Nemesis.",
"title": "Theology"
},
{
"paragraph_id": 47,
"text": "Outside of Italy, Diana had important centers of worship where she was syncretised with similar local deities in Gaul, Upper Germania, and Britannia. Diana was particularly important in the region in and around the Black Forest, where she was conflated with the local goddess Abnoba and worshiped as Diana Abnoba.",
"title": "Theology"
},
{
"paragraph_id": 48,
"text": "Some late antique sources went even further, syncretizing many local \"great goddesses\" into a single \"Queen of Heaven\". The Platonist philosopher Apuleius, writing in the late 2nd century, depicted the goddess declaring:",
"title": "Theology"
},
{
"paragraph_id": 49,
"text": "\"I come, Lucius, moved by your entreaties: I, mother of the universe, mistress of all the elements, first-born of the ages, highest of the gods, queen of the shades, first of those who dwell in heaven, representing in one shape all gods and goddesses. My will controls the shining heights of heaven, the health-giving sea-winds, and the mournful silences of hell; the entire world worships my single godhead in a thousand shapes, with divers rites, and under many a different name. The Phrygians, first-born of mankind, call me the Pessinuntian Mother of the gods; the native Athenians the Cecropian Minerva; the island-dwelling Cypriots Paphian Venus; the archer Cretans Dictynnan Diana; the triple-tongued Sicilians Stygian Proserpine; the ancient Eleusinians Actaean Ceres; some call me Juno, some Bellona, others Hecate, others Rhamnusia; but both races of Ethiopians, those on whom the rising and those on whom the setting sun shines, and the Egyptians who excel in ancient learning, honour me with the worship which is truly mine and call me by my true name: Queen Isis.\"",
"title": "Theology"
},
{
"paragraph_id": 50,
"text": "Later poets and historians looked to Diana's identity as a triple goddess to merge her with triads heavenly, earthly, and underworld (cthonic) goddesses. Maurus Servius Honoratus said that the same goddess was called Luna in heaven, Diana on earth, and Proserpina in hell. Michael Drayton praises the Triple Diana in poem The Man in the Moone (1606): \"So these great three most powerful of the rest, Phoebe, Diana, Hecate, do tell. Her sovereignty in Heaven, in Earth and Hell\".",
"title": "Theology"
},
{
"paragraph_id": 51,
"text": "Based on the earlier writings of Plato, the Neoplatonist philosophers of late antiquity united the various major gods of Hellenic tradition into a series of monads containing within them triads, with some creating the world, some animating it or bringing it to life, and others harmonizing it. Within this system, Proclus considered Diana to be one of the primary animating, or life-giving, deities. Proclus, citing Orphic tradition, concludes that Diana \"presides over all the generation in nature, and is the midwife of physical productive principles\" and that she \"extends these genitals, distributing as far as to subterranean natures the prolific power of [Bacchus].\" Specifically, Proclus considered the life-generating principle of the highest order, within the Intellectual realm, to be Rhea, whom he identified with Ceres. Within her divinity was produced the cause of the basic principle of life. Projecting this principle into the lower, Hypercosmic realm of reality generated a lower monad, Kore, who could therefore be understood as Ceres' \"daughter\". Kore embodied the \"maidenly\" principle of generation that, more importantly, included a principle of division – where Demeter generates life indiscriminately, Kore distributes it individually. This division results in another triad or trinity, known as the Maidenly trinity, within the monad of Kore: namely, Diana, Proserpine, and Minerva, through whom individual living beings are given life and perfected. Specifically, according to a commentary by scholar Spyridon Rangos, Diana (equated with Hecate) gives existence, Proserpine (equated with \"Soul\") gives form, and Minerva (equated with \"Virtue\") gives intellect.",
"title": "Theology"
},
{
"paragraph_id": 52,
"text": "In his commentary on Proclus, the 19th century Platonist scholar Thomas Taylor expanded upon the theology of the classical philosophers, further interpreting the nature and roles of the gods in light of the whole body of Neoplatonist philosophy. He cites Plato in giving a three-form aspect to her central characteristic of virginity: the undefiled, the mundane, and the anagogic. Through the first form, Diana is regarded as a \"lover of virginity\". Through the second, she is the guardian of virtue. Through the third, she is considered to \"hate the impulses arising from generation.\" Through the principle of the undefiled, Taylor suggests that she is given supremacy in Proclus' triad of life-giving or animating deities, and in this role the theurgists called her Hekate. In this role, Diana is granted undefiled power (Amilieti) from the other gods. This generative power does not proceed forth from the goddess (according to a statement by the Oracle of Delphi) but rather resides with her, giving her unparalleled virtue, and in this way she can be said to embody virginity. Later commentators on Proclus have clarified that the virginity of Diana is not an absence of sexual drive, but a renunciation of sexuality. Diana embodies virginity because she generates but precedes active fertility (within Neoplatonism, an important maxim is that \"every productive cause is superior to the nature of the produced effect\").",
"title": "Theology"
},
{
"paragraph_id": 53,
"text": "Using the ancient Neoplatonists as a basis, Taylor also commented on the triadic nature of Diana and related goddesses, and the ways in which they subsist within one another, partaking unevenly in each other's powers and attributes. For example, Kore is said to embody both Diana/Hecate and Minerva, who create the virtuous or virgin power within her, but also Proserpine (her sole traditional identification), through whom the generative power of the Kore as a whole is able to proceed forth into the world, where it joins with the demiurge to produce further deities, including Bacchus and \"nine azure-eyed, flower-producing daughters\".",
"title": "Theology"
},
{
"paragraph_id": 54,
"text": "Proclus also included Artemis/Diana in a second triad of deities, along with Ceres and Juno. According to Proclus:",
"title": "Theology"
},
{
"paragraph_id": 55,
"text": "Proclus pointed to the conflict between Hera and Artemis in the Illiad as a representation of the two kinds of human souls. Where Hera creates the higher, more cultured, or \"worthy\" souls, Artemis brings light to and perfects the \"less worthy\" or less rational. As explained by Ragnos (2000), \"The aspect of reality which Artemis and Hera share, and because of which they engage in a symbolic conflict, is the engendering of life.\" Hera elevates rational living beings up to intellectual rational existence, whereas Artemis's power pertains to human life as far as its physical existence as a living thing. \"Artemis deals with the most elementary forms of life or the most elementary part of all life, whereas Hera operates in the most elevated forms of life or the most elevated part of all life.",
"title": "Theology"
},
{
"paragraph_id": 56,
"text": "Sermons and other religious documents have provided evidence for the worship of Diana during the Middle Ages. Though few details have been recorded, enough references to Diana worship during the early Christian period exist to give some indication that it may have been relatively widespread among remote and rural communities throughout Europe, and that such beliefs persisted into the Merovingian period. References to contemporary Diana worship exist from the 6th century on the Iberian peninsula and what is now southern France, though more detailed accounts of Dianic cults were given for the Low Countries, and southern Belgium in particular. Many of these were probably local goddesses, and wood nymphs or dryads, which had been conflated with Diana by Christian writers Latinizing local names and traditions.",
"title": "Worship in Post Roman Europe"
},
{
"paragraph_id": 57,
"text": "The 6th century bishop Gregory of Tours reported meeting with a deacon named Vulfilaic (also known as Saint Wulflaicus or Walfroy the Stylite), who founded a hermitage on a hill in what is now Margut, France. On the same hill, he found \"an image of Diana which the unbelieving people worshiped as a god.\" According to Gregory's report, worshipers would also sing chants in Diana's honor as they drank and feasted. Vulfilaic destroyed a number of smaller pagan statues in the area, but the statue of Diana was too large. After converting some of the local population to Christianity, Vulfilaic and a group of local residents attempted to pull the large statue down the mountain in order to destroy it, but failed, as it was too large to be moved. In Vulfilaic's account, after praying for a miracle, he was then able to single-handedly pull down the statue, at which point he and his group smashed it to dust with their hammers. According to Vulfilaic, this incident was quickly followed by an outbreak of pimples or sores that covered his entire body, which he attributed to demonic activity and similarly cured via what he described as a miracle. Vulfilaic would later found a church on the site, which is today known as Mont Saint-Walfroy.",
"title": "Worship in Post Roman Europe"
},
{
"paragraph_id": 58,
"text": "Additional evidence for surviving pagan practices in the Low Countries region comes from the Vita Eligii, or \"Life of Saint Eligius\", written by Audoin in the 7th century. Audoin drew together the familiar admonitions of Eligius to the people of Flanders. In his sermons, he denounced \"pagan customs\" that the people continued to follow. In particular, he denounced several Roman gods and goddesses alongside Druidic mythological beliefs and objects:",
"title": "Worship in Post Roman Europe"
},
{
"paragraph_id": 59,
"text": "\"I denounce and contest, that you shall observe no sacrilegious pagan customs. For no cause or infirmity should you consult magicians, diviners, sorcerers or incantators. ..Do not observe auguries ... No influence attaches to the first work of the day or the [phase of the] moon. ... [Do not] make vetulas, little deer or iotticos or set tables at night or exchange New Year gifts or supply superfluous drinks... No Christian... performs solestitia or dancing or leaping or diabolical chants. No Christian should presume to invoke the name of a demon, not Neptune or Orcus or Diana or Minerva or Geniscus... No one should observe Jove's day in idleness. ... No Christian should make or render any devotion to the gods of the trivium, where three roads meet, to the fanes or the rocks, or springs or groves or corners. None should presume to hang any phylacteries from the neck of man nor beast. ..None should presume to make lustrations or incantations with herbs, or to pass cattle through a hollow tree or ditch ... No woman should presume to hang amber from her neck or call upon Minerva or other ill-starred beings in their weaving or dyeing. .. None should call the sun or moon lord or swear by them. .. No one should tell fate or fortune or horoscopes by them as those do who believe that a person must be what he was born to be.\"",
"title": "Worship in Post Roman Europe"
},
{
"paragraph_id": 60,
"text": "Legends from medieval Belgium concern a natural spring which came to be known as the \"Fons Remacli\", a location which may have been home to late-surviving worship of Diana. Remacle was a monk appointed by Eligius to head a monastery at Solignac, and he is reported to have encountered Diana worship in the area around the river Warche. The population in this region was said to have been involved in the worship of \"Diana of the Ardennes\" (a syncretism of Diana and the Celtic goddess Arduinna), with effigies and \"stones of Diana\" used as evidence of pagan practices. Remacle believed that demonic entities were present in the spring, and had caused it to run dry. He performed and exorcism of the water source, and installed a lead pipe, which allowed the water to flow again.",
"title": "Worship in Post Roman Europe"
},
{
"paragraph_id": 61,
"text": "Diana is the only pagan goddess mentioned by name in the New Testament (only in some Bible versions of Acts 19; many other Bibles refer to her as Artemis instead). As a result, she became associated with many folk beliefs involving goddess-like supernatural figures that Catholic clergy wished to demonize. In the Middle Ages, legends of night-time processions of spirits led by a female figure are recorded in the church records of Northern Italy, western Germany, and southern France. The spirits were said to enter houses and consume food which then miraculously re-appeared. They would sing and dance, and dispense advice regarding healing herbs and the whereabouts of lost objects. If the house was in good order, they would bring fertility and plenty. If not, they would bring curses to the family. Some women reported participating in these processions while their bodies still lay in bed. Historian Carlo Ginzburg has referred to these legendary spirit gatherings as \"The Society of Diana\".",
"title": "Worship in Post Roman Europe"
},
{
"paragraph_id": 62,
"text": "Local clergy complained that women believed they were following Diana or Herodias, riding out on appointed nights to join the processions or carry out instructions from the goddess. The earliest reports of these legends appear in the writings of Regino of Prüm in the year 899, followed by many additional reports and variants of the legend in documents by Ratherius and others. By 1310, the names of the goddess figures attached to the legend were sometimes combined as Herodiana. It is likely that the clergy of this time used the identification of the procession's leader as Diana or Herodias in order to fit an older folk belief into a Biblical framework, as both are featured and demonized in the New Testament. Herodias was often conflated with her daughter Salome in legend, which also holds that, upon being presented with the severed head of John the Baptist, she was blown into the air by wind from the saint's mouth, through which she continued to wander for eternity. Diana was often conflated with Hecate, a goddess associated with the spirits of the dead and with witchcraft. These associations, and the fact that both figures are attested to in the Bible, made them a natural fit for the leader of the ghostly procession. Clergy used this identification to assert that the spirits were evil, and that the women who followed them were inspired by demons. As was typical of this time period, though pagan beliefs and practices were near totally eliminated from Europe, the clergy and other authorities still treated paganism as a real threat, in part thanks to biblical influence; much of the Bible had been written when various forms of paganism were still active if not dominant, so medieval clergy applied the same kinds of warnings and admonitions for any non-standard folk beliefs and practices they encountered. Based on analysis of church documents and parishioner confessions, it is likely that the spirit identified by the Church as Diana or Herodias was called by names of pre-Christian figures like Holda (a Germanic goddess of the winter solstice), or with names referencing her bringing of prosperity, like the Latin Abundia (meaning \"plenty\"), Satia (meaning \"full\" or \"plentiful\") and the Italian Richella (meaning \"rich\"). Some of the local titles for her, such as bonae res (meaning \"good things\"), are similar to late classical titles for Hecate, like bona dea. This might indicate a cultural mixture of medieval folk ideas with holdovers from earlier pagan belief systems. Whatever her true origin, by the 13th century, the leader of the legendary spirit procession had come to be firmly identified with Diana and Herodias through the influence of the Church.",
"title": "Worship in Post Roman Europe"
},
{
"paragraph_id": 63,
"text": "In his wide-ranging, comparative study of mythology and religion, The Golden Bough, anthropologist James George Frazer drew on various lines of evidence to re-interpret the legendary rituals associated with Diana at Nemi, particularly that of the rex Nemorensis. Frazer developed his ideas in relation to J. M. W. Turner's painting, also titled The Golden Bough, depicting a dream-like vision of the woodland lake of Nemi. According to Frazer, the rex Nemorensis or king at Nemi was the incarnation of a dying and reviving god, a solar deity who participated in a mystical marriage to a goddess. He died at the harvest and was reincarnated in the spring. Frazer claimed that this motif of death and rebirth is central to nearly all of the world's religions and mythologies. In Frazer's theory, Diana functioned as a goddess of fertility and childbirth, who, assisted by the sacred king, ritually returned life to the land in spring. The king in this scheme served not only as a high priest but as a god of the grove. Frazer identifies this figure with Virbius, of which little is known, but also with Jupiter via an association with sacred oak trees. Frazer argued furthermore that Jupiter and Juno were simply duplicate names of Jana and Janus; that is, Diana and Dianus, all of whom had identical functions and origins.",
"title": "Modern development and folklore"
},
{
"paragraph_id": 64,
"text": "Frazer's speculatively reconstructed folklore of Diana's origins and the nature of her cult at Nemi were not well received even by his contemporaries. Godfrey Lienhardt noted that even during Frazer's lifetime, other anthropologists had \"for the most part distanced themselves from his theories and opinions\", and that the lasting influence of The Golden Bough and Frazer's wider body of work \"has been in the literary rather than the academic world.\" Robert Ackerman wrote that, for anthropologists, Frazer is \"an embarrassment\" for being \"the most famous of them all\" and that most distance themselves from his work. While The Golden Bough achieved wide \"popular appeal\" and exerted a \"disproportionate\" influence \"on so many [20th century] creative writers\", Frazer's ideas played \"a much smaller part\" in the history of academic social anthropology.",
"title": "Modern development and folklore"
},
{
"paragraph_id": 65,
"text": "Folk legends like the Society of Diana, which linked the goddess to forbidden gatherings of women with spirits, may have influenced later works of folklore. One of these is Charles Godfrey Leland's Aradia, or the Gospel of the Witches, which prominently featured Diana at the center of an Italian witch-cult. In Leland's interpretation of supposed Italian folk witchcraft, Diana is considered Queen of the Witches. In this belief system, Diana is said to have created the world of her own being having in herself the seeds of all creation yet to come. It was said that out of herself she divided the darkness and the light, keeping for herself the darkness of creation and creating her brother Lucifer. Diana was believed to have loved and ruled with her brother, and with him bore a daughter, Aradia (a name likely derived from Herodias), who leads and teaches the witches on earth.",
"title": "Modern development and folklore"
},
{
"paragraph_id": 66,
"text": "Leland's claim that Aradia represented an authentic tradition from an underground witch-cult, which had secretly worshiped Diana since ancient times has been dismissed by most scholars of folklore, religion, and medieval history. After the 1921 publication of Margaret Murray's The Witch-cult in Western Europe, which hypothesized that the European witch trials were actually a persecution of a pagan religious survival, American sensationalist author Theda Kenyon's 1929 book Witches Still Live connected Murray's thesis with the witchcraft religion in Aradia. Arguments against Murray's thesis would eventually include arguments against Leland. Witchcraft scholar Jeffrey Russell devoted some of his 1980 book A History of Witchcraft: Sorcerers, Heretics and Pagans to arguing against the claims Leland presented in Aradia. Historian Elliot Rose's A Razor for a Goat dismissed Aradia as a collection of incantations unsuccessfully attempting to portray a religion. In his book Triumph of the Moon, historian Ronald Hutton doubted not only of the existence of the religion that Aradia claimed to represent, and that the traditions Leland presented were unlike anything found in actual medieval literature, but also of the existence of Leland's sources, arguing that it is more likely that Leland created the entire story than that Leland could be so easily \"duped\". Religious scholar Chas S. Clifton took exception to Hutton's position, writing that it amounted to an accusation of \"serious literary fraud\" made by an \"argument from absence\".",
"title": "Modern development and folklore"
},
{
"paragraph_id": 67,
"text": "Building on the work of Frazer, Murray, and others, some 20th and 21st century authors have attempted to identify links between Diana and more localized deities. R. Lowe Thompson, for example, in his 2013 book The History of the Devil, speculated that Diana may have been linked as an occasional \"spouse\" to the Gaulish horned god Cernunnos. Thompson suggested that Diana in her role as wild goddess of the hunt would have made a fitting consort for Cernunnos in Western Europe, and further noted the link between Diana as Proserpina with Pluto, the Greek god associated with the riches of the earth who served a similar role to the Gaulish Cernunnos.",
"title": "Modern development and folklore"
},
{
"paragraph_id": 68,
"text": "Because Leland's claims about an Italian witch-cult are questionable, the first verifiable worship of Diana in the modern age was probably begun by Wicca. The earliest known practitioners of Neopagan witchcraft were members of a tradition begun by Gerald Gardner. Published versions of the devotional materials used by Gardner's group, dated to 1949, are heavily focused on the worship of Aradia, the daughter of Diana in Leland's folklore. Diana herself was recognized as an aspect of a single \"great goddess\" in the tradition of Apuleius, as described in the Wiccan Charge of the Goddess (itself adapted from Leland's text). Some later Wiccans, such as Scott Cunningham, would replace Aradia with Diana as the central focus of worship.",
"title": "Modern development and folklore"
},
{
"paragraph_id": 69,
"text": "In the early 1960s, Victor Henry Anderson founded the Feri Tradition, a form of Wicca that draws from both Charles Leland's folklore and the Gardnerian tradition. Anderson claimed that he had first been initiated into a witchcraft tradition as a child in 1926, and that he had been told the name of the goddess worshiped by witches was Tana. The name Tana originated in Leland's Aradia, where he claimed it was an old Etruscan name for Diana. The Feri Tradition founded by Anderson continues to recognize Tana/Diana as an aspect of the Star Goddess related to the element of fire, and representing \"the fiery womb that gives birth to and transforms all matter.\" (In Aradia, Diana is also credited as the creatrix of the material world and Queen of Faeries).",
"title": "Modern development and folklore"
},
{
"paragraph_id": 70,
"text": "A few Wiccan traditions would elevate Diana to a more prominent position of worship, and there are two distinct modern branches of Wicca focused primarily on Diana. The first, founded during the early 1970s in the United States by Morgan McFarland and Mark Roberts, has a feminist theology and only occasionally accepts male participants, and leadership is limited to female priestesses. McFarland Dianic Wiccans base their tradition primarily on the work of Robert Graves and his book The White Goddess, and were inspired by references to the existence of medieval European \"Dianic cults\" in Margaret Murray's book The Witch-Cult in Western Europe. The second Dianic tradition, founded by Zsuzsanna Budapest in the mid 1970s, is characterized by an exclusive focus on the feminine aspect of the divine, and as a result is exclusively female. This tradition combines elements from British Traditional Wicca, Italian folk-magic based on the work of Charles Leland, feminist values, and healing practices drawn from a variety of different cultures.",
"title": "Modern development and folklore"
},
{
"paragraph_id": 71,
"text": "A third Neopagan tradition heavily inspired by the worship of Diana through the lens of Italian folklore is Stregheria, founded in the 1980s. It centers around a pair of deities regarded as divine lovers, who are known by several variant names including Diana and Dianus, alternately given as Tana and Tanus or Jana and Janus (the later two deity names were mentioned by James Frazer in The Golden Bough as later corruptions of Diana and Dianus, which themselves were alternate and possibly older names for Juno and Jupiter). The tradition was founded by author Raven Grimassi, and influenced by Italian folktales he was told by his mother. One such folktale describes the moon being impregnated by her lover the morning star, a parallel to Leland's mythology of Diana and her lover Lucifer.",
"title": "Modern development and folklore"
},
{
"paragraph_id": 72,
"text": "Diana was also a subject of worship in certain Feraferian rites, particularly those surrounding the autumnal equinox, beginning in 1967.",
"title": "Modern development and folklore"
},
{
"paragraph_id": 73,
"text": "Both the Romanian words for \"fairy\" Zână and Sânziană, the Leonese and Portuguese word for \"water nymph\" xana, and the Spanish word for \"shooting target\" and \"morning call\" (diana) seem to come from the name of Diana.",
"title": "Legacy"
},
{
"paragraph_id": 74,
"text": "Since the Renaissance, Diana's myths have often been represented in the visual and dramatic arts, including the opera L'arbore di Diana. In the 16th century, Diana's image figured prominently at the châteaus of Fontainebleau, Chenonceau, and at Anet, in deference to Diane de Poitiers, mistress of Henri of France. At Versailles she was incorporated into the Olympian iconography with which Louis XIV, the Apollo-like \"Sun King\" liked to surround himself. Diana is also a character in the 1876 Léo Delibes ballet Sylvia. The plot deals with Sylvia, one of Diana's nymphs and sworn to chastity, and Diana's assault on Sylvia's affections for the shepherd Amyntas.",
"title": "Legacy"
},
{
"paragraph_id": 75,
"text": "Diana has been one of the most popular themes in art. Painters like Titian, Peter Paul Rubens, François Boucher, Nicolas Poussin and made use of her myth as a major theme. Most depictions of Diana in art featured the stories of Diana and Actaeon, or Callisto, or depicted her resting after hunting. Some famous work of arts with a Diana theme are:",
"title": "Legacy"
},
{
"paragraph_id": 76,
"text": "There are many statues of Diana the Huntress in Yambol, Bulgaria.",
"title": "Legacy"
}
] | Diana is a goddess in Roman and Hellenistic religion, primarily considered a patroness of the countryside and nature, hunters, wildlife, childbirth, crossroads, the night, and the Moon. She is equated with the Greek goddess Artemis, and absorbed much of Artemis' mythology early in Roman history, including a birth on the island of Delos to parents Jupiter and Latona, and a twin brother, Apollo, though she had an independent origin in Italy. Diana is considered a virgin goddess and protector of childbirth. Historically, Diana made up a triad with two other Roman deities: Egeria the water nymph, her servant and assistant midwife; and Virbius, the woodland god. Diana is revered in modern neopagan religions including Roman neopaganism, Stregheria, and Wicca. In the ancient, medieval, and modern periods, Diana has been considered a triple deity, merged with a goddess of the moon (Luna/Selene) and the underworld. | 2001-09-24T07:13:11Z | 2023-11-24T19:22:54Z | [
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8,396 | December 11 | December 11 is the 345th day of the year (346th in leap years) in the Gregorian calendar; 20 days remain until the end of the year. | [
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"paragraph_id": 0,
"text": "December 11 is the 345th day of the year (346th in leap years) in the Gregorian calendar; 20 days remain until the end of the year.",
"title": ""
}
] | December 11 is the 345th day of the year in the Gregorian calendar; 20 days remain until the end of the year. | 2001-10-18T16:31:34Z | 2023-12-19T13:23:15Z | [
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8,397 | Danny Elfman | Daniel Robert Elfman (born May 29, 1953) is an American film composer, singer, songwriter, and musician. He came to prominence as the lead singer and primary songwriter for the new wave band Oingo Boingo in the early 1980s. Since scoring his first studio film in 1985, Elfman has garnered international recognition for composing over 100 feature film scores, as well as compositions for television, stage productions, and the concert hall.
Elfman has frequently worked with directors Tim Burton, Sam Raimi, and Gus Van Sant, contributing music to nearly 20 Burton projects, including Pee-Wee's Big Adventure, Batman, Edward Scissorhands, and Wednesday, as well as scoring Raimi's Darkman, A Simple Plan, Spider-Man, Spider-Man 2 and Doctor Strange in the Multiverse of Madness, and Van Sant's Academy Award-winning films Good Will Hunting and Milk. He wrote music for all of the Men in Black and Fifty Shades of Grey franchise films, the songs and score for Henry Selick's animated musical The Nightmare Before Christmas, and the themes for the popular television series Desperate Housewives and The Simpsons.
Among his honors are four Oscar nominations, two Emmy Awards, a Grammy, seven Saturn Awards for Best Music, the 2002 Richard Kirk Award, the 2015 Disney Legend Award, the Max Steiner Film Music Achievement Award in 2017, and the Society of Composers & Lyricists Lifetime Achievement Award in 2022.
Elfman was born on May 29, 1953, in Los Angeles, California, to a Jewish family of Polish and Russian descent. He is a son of Blossom Elfman (née Bernstein), a writer and teacher, and Milton Elfman, a teacher, and the brother of actor, musician, and journalist Richard Elfman. Elfman was raised in a racially mixed affluent community in Baldwin Hills, California, where he spent much of his time at the local cinema discovering classic sci-fi, fantasy and horror films and first noticed the music of such film composers as Bernard Herrmann and Franz Waxman. Elfman has admitted to fabricating stories about his past out of boredom, including a false birthplace of Amarillo, Texas, and parents in the United States Air Force.
In his early school days, Elfman exhibited an aptitude for science with almost no interest in music, and was even rejected from elementary school orchestra "for having no propensity for music." This would change when he switched high schools in the late 1960s and fell in with a musical crowd, who introduced him to early jazz and the work of Stravinsky and his 20th-century contemporaries.
After finishing high school early with plans to travel the world, Elfman followed his brother Richard to France, where he performed violin with Jérôme Savary's Le Grand Magic Circus, an avant-garde musical theater group. He then embarked on a ten-month, self-guided tour through Africa, busking and collecting a range of West African percussion instruments until a series of illnesses forced him to return home. At this time, Richard was forming a new musical theater group in Los Angeles.
After returning to Los Angeles from Africa in the early 1970s, Elfman was asked by his brother Richard to serve as musical director of his street theatre performance art troupe The Mystic Knights of the Oingo Boingo. Elfman was tasked with adapting and arranging 1920s and 1930s jazz and big band music by artists such as Cab Calloway, Duke Ellington, Django Reinhardt and Josephine Baker for the ensemble, which consisted of up to 15 performers playing upwards of 30 instruments. He also composed original pieces and helped build instruments unique for the group, including an aluminum gamelan, the 'Schlitz celeste' made from tuned beer cans, and a "junkyard orchestra" built from car parts and trash cans.
The Mystic Knights performed on the street and in theaters, and later in nightclubs throughout Los Angeles until Richard left in 1976 to pursue filmmaking. As a send-off to the group's original concept, Richard produced the film Forbidden Zone based on the Mystic Knights' stage performances. Elfman composed the songs and his first score for the film, and appeared as the character Satan, who performs a reworked version of Calloway's "Minnie the Moocher."
Before the release of Forbidden Zone, Elfman took over the Mystic Knights as lead singer-songwriter in 1976. In 1979, he pared the group down to eight players to record and tour as a ska-influenced new wave band. That summer, the group's name would change to Oingo Boingo. Their biggest success among eight studio albums penned by Elfman was 1985's Dead Man's Party, featuring the hit song "Weird Science" from the movie of the same name. The band also appeared performing their single "Dead Man's Party" in the 1986 movie Back to School, for which Elfman also composed the score. Elfman shifted the band to a more guitar-oriented rock sound in the late 1980s, which continued through their last album Boingo in 1994.
Citing permanent hearing damage from performing live and conflicts with his film-scoring career, Elfman retired Oingo Boingo in 1995 with a series of five sold-out final concerts at the Universal Amphitheatre ending on Halloween night. On October 31, 2015, Elfman and Oingo Boingo guitarist Steve Bartek performed the song "Dead Man's Party" with an orchestra as an encore to a live-to-film concert of The Nightmare Before Christmas score at the Hollywood Bowl. Elfman told the audience the performance was "20 years to the day" of Oingo Boingo's retirement.
As fans of Oingo Boingo, Tim Burton and Paul Reubens invited Elfman to write the score for their first feature film Pee-wee's Big Adventure in 1985. Elfman was initially apprehensive because of his lack of formal training and having never scored a studio feature, but after Burton accepted his initial demo of the title music, and with orchestration assistance from Oingo Boingo guitarist and arranger Steve Bartek, Elfman completed the score to great effect, paying homage to influential film composers Nino Rota and Bernard Herrmann. Elfman described the first time he heard his music played by a full orchestra as one of the most thrilling experiences of his life.
Following Pee Wee's Big Adventure, Elfman scored a string of comedies in the late 1980s, including Back to School starring Rodney Dangerfield, Burton's Beetlejuice and the Bill Murray film Scrooged. Non-comedy work included the all-synth score to Emilio Estevez's crime drama Wisdom and the big band, blues-infused music for Martin Brest's buddy cop action film Midnight Run.
In 1989, Elfman's influential, Grammy-winning score for Burton's Batman marked a major stylistic shift to dark, densely orchestrated music in the romantic idiom. This continued in his scores for Warren Beatty's Dick Tracy, Sam Raimi's Darkman and Clive Barker's Nightbreed, all released in 1990.
With Batman, Elfman firmly established a career-spanning relationship with Burton, scoring all but three of the director's major studio releases. Highlights include Edward Scissorhands (1990), Batman Returns (1992), Sleepy Hollow (1999), Big Fish (2003) and Alice in Wonderland (2010). In 1993, Elfman wrote the score and ten songs for the Burton-produced stop motion animated film The Nightmare Before Christmas, directed by Henry Selick, and also provided the singing voice for main character Jack Skellington, as well as the voices for secondary characters Barrel, the Clown with the Tear-Away Face and others. In 2005, he wrote the score and songs for Burton's Corpse Bride and provided the voice of the character of Bonejangles, and provided the score, songs and Oompa-Loompa vocals for Burton's Charlie and the Chocolate Factory that same year.
In addition to frequent collaborations with Burton, Raimi and Gus Van Sant, Elfman has worked with directors such as Brian De Palma, Peter Jackson, Joss Whedon, Errol Morris, Ang Lee, Richard Donner, Guillermo del Toro, David O. Russell, Taylor Hackford, Jon Amiel, Joe Johnston, and Barry Sonnenfeld. His scores for Sonnenfeld's Men in Black, Van Sant's Good Will Hunting and Milk, and Burton's Big Fish all received Academy Award nominations.
Since the mid-1990s, Elfman expanded his craft to a range of genres, including thrillers (Dolores Claiborne, A Simple Plan, The Kingdom, The Girl on the Train, The Woman in the Window), dramas (Sommersby, A Civil Action, Hitchcock), indies (Freeway, Silver Linings Playbook, Don't Worry, He Won't Get Far on Foot, White Noise), family (Flubber, Charlotte's Web, Frankenweenie, Goosebumps, Dolittle), documentary (Standard Operating Procedure, The Unknown Known), and horror (Red Dragon, The Wolfman), as well as entries in his well-established areas of horror comedy (The Frighteners, Mars Attacks!, Dark Shadows) and comic book-inspired action films (Hulk, Wanted, Hellboy II: The Golden Army).
Among his franchise work, Elfman composed the scores for four Men in Black films (1997–2019) and three Fifty Shades films (2015–2018). In 1996, he scored the first film in the Mission: Impossible series, adapting themes for the original television series by Lalo Schifrin as well as composing his own. Elfman scored Raimi's Spider-Man in 2002 and Spider-Man 2 in 2004, themes and selections from which were used for Raimi's Spider-Man 3, scored by Christopher Young. Elfman's Spider-Man theme was incorporated into the MCU film Spider-Man: No Way Home composed by Michael Giacchino.
Elfman entered the Marvel Cinematic Universe by providing additional music an 2015's Avengers: Age of Ultron, receiving composer credit with Brian Tyler. Elfman also scored MCU's Doctor Strange in the Multiverse of Madness in 2022, utilizing Giacchino's theme to the original Doctor Strange film, as well as themes from WandaVision and X-Men: The Animated Series, and music from Beethoven's Fifth Symphony and Bach's Toccata and Fugue.
For several high-profile sequel and reboot projects in the 2010s, Elfman incorporated established musical themes with his own original thematic material, including the DC Extended Universe's Justice League, The Grinch, Dumbo and Men in Black International.
Elfman was featured in the 2016 documentary Score, in which he appeared among over 50 film composers to discuss the craft of movie music and influential figures in the business.
Elfman's first piece of original concert music, Serenada Schizophrana, was commissioned by the American Composers Orchestra, who premiered the piece on February 23, 2005, at Carnegie Hall. Subsequent concert works include his first Violin Concerto "Eleven Eleven", co-commissioned by the Czech National Symphony Orchestra, Stanford Live at Stanford University, and the Royal Scottish National Orchestra, which premiered at Smetana Hall in Prague on June 21, 2017, with Sandy Cameron on violin and John Mauceri conducting the Czech National Symphony Orchestra; the Piano Quartet, co-commissioned by the Lied Center for Performing Arts University of Nebraska and the Berlin Philharmonic Piano Quartet, which premiered February 6, 2018, in Lincoln, Nebraska; and the Percussion Quartet, commissioned by Third Coast Percussion and premiered at the Philip Glass Days And Nights Festival in Big Sur on October 10, 2019.
2022 saw the first performances of three concert works. Elfman's Cello Concerto composed Gautier Capucon premiered by the Vienna Symphony in March, with subsequent performances by the Orchestre Philharmonique de Radio France in May and The San Francisco Symphony US premiere in November Elfman's Percussion Concerto for Colin Currie premiered at London's Royal Festival Hall with London Philharmonic Orchestra, and was later performed at Soka University of America in California, with Pacific Symphony. His Wunderkammer, a commission from the National Youth Orchestra of Great Britain, toured the UK in summer 2022, culminating in a performance in London's Royal Albert Hall as part of the BBC Proms, with national radio and TV broadcasts.
In 2008, Elfman accepted his first commission for the stage, composing the music for Twyla Tharp's Rabbit and Rogue ballet, co-commissioned by American Ballet Theatre and Orange County Performing Arts Center and premiering on June 3, 2008, at the Metropolitan Opera House, Lincoln Center. Other works for stage include the music for Cirque Du Soleil's Iris in 2011, and incidental music for the Broadway production of Taylor Mac's Gary: A Sequel to Titus Andronicus in 2019.
In October 2013, Elfman returned to the stage for the first time since his band Oingo Boingo disbanded to sing a handful of The Nightmare Before Christmas songs as part of the concert Danny Elfman's Music from the Films of Tim Burton, featuring suites of music from 15 Tim Burton films newly arranged by Elfman. The concert has since toured internationally and has played in Japan, Australia, Mexico and throughout Europe and the United States. Since 2015, Elfman has appeared regularly in a Hollywood Bowl Halloween concert featuring full orchestra performing the Nightmare Before Christmas score live to the film projection.
Elfman made his Coachella debut on April 16, 2022, with Danny Elfman: From Boingo to Batman to Big Mess to Beyond! The concert, postponed from Coachella 2020 due to the COVID-19 pandemic, featured Elfman's film and television music arranged for band, orchestra and choir, as well as songs from his solo album Big Mess and new arrangements of songs from his Oingo Boingo catalogue. Conducted by Steve Bartek, and featuring Elfman (vocals, guitar, percussion), Wes Borland (guitar), Stu Brooks (bass), Nili Brosh (guitar), and Josh Freese (drums), the concert was expanded for two shows Halloween weekend 2022 at the Hollywood Bowl.
In addition to his music for film, Elfman also penned themes for the television series The Simpsons, Tales from the Crypt, The Flash and Desperate Housewives, which won Elfman his first Emmy. He also adapted his original themes for the animated versions of Batman and Beetlejuice. Occasional forays into serial television include episodes of Alfred Hitchcock Presents, Amazing Stories and Pee-wee's Playhouse, the miniseries When We Rise co-composed with Chris Bacon, and themes for the Netflix series Wednesday.
He has composed music for animated shorts, including Sally Cruikshank's Face Like A Frog and Tim Burton's "Stainboy" internet series.
Elfman provided background music for Luigi Serafini's solo exhibition il Teatro della Pittura at the Fondazione Mudima di Milano in Milan, Italy in 1998 and for the Tim Burton exhibition at MoMA in 2009.
In the 1990s, Elfman composed music for advertising campaigns for Nike, Nissan and Lincoln-Mercury, and in 2002 wrote the music for Honda's "Power of Dreams" advertising campaign, which was the first cinema commercial to be shot in the IMAX format.
In 2013 he composed the music and provided the English-language vocals for the Hong Kong Disneyland attraction Mystic Manor.
On October 31, 2019, the MasterClass online educational series released "Making Music out of Chaos," presenting 21 compositional and career lessons from Elfman's four decades of experience primarily in the film industry.
Elfman scored the 10-minute video "Joe Biden," which introduced Joe Biden's acceptance of the presidential candidacy nomination at the 2020 Democratic National Convention.
On November 16, 2021, Disney Branded Television announced that Elfman would compose score and songs of the upcoming Disney Television Animation and 20th Television Animation stop-motion animated comedy series "Rhona Who Lives By The River" created by Emily Kapnek, Elfman also serves as executive producer for the series.
In October 2020, Elfman released the single, "Happy," on Anti- Records and Epitaph Records. From January 2021 on the eleventh day of each month, he released five subsequent singles "Sorry", "Love in the Time of COVID", "Kick Me", "True", and a reworking the Oingo Boingo song "Insects" from the album Nothing to Fear. This culminated with the release of the double album Big Mess on June 11. Featuring 18 original songs this was Elfman's first solo studio album since 1984's So-Lo.
On August 11, 2021, Elfman released a remix of "True" with lead vocals shared between Elfman and Nine Inch Nails frontman Trent Reznor. A year later, Elfman released Bigger Messier, a compilation of 23 remixes of songs on the album Big Mess by artists including Reznor, Iggy Pop, Blixa Bargeld, Squarepusher, Boy Harsher and more.
Elfman has said his major influences are composers from Hollywood's Golden Age, such as Bernard Herrmann, Dimitri Tiomkin, Max Steiner, David Tamkin, Erich Wolfgang Korngold, and Carl Stalling; 20th century classical composers Sergei Prokofiev, Igor Stravinsky, Béla Bartók, Dmitri Shostakovich, and Carl Orff; and jazz, experimental and minimalist composers Kurt Weill, Duke Ellington, Harry Partch, Philip Glass, Lou Harrison, Terry Riley, and Steve Reich. Influences on specific scores include Erik Satie (Forbidden Zone), Nino Rota (Pee-wee's Big Adventure), George Gershwin (Dick Tracy), Pyotr Ilyich Tchaikovsky (Edward Scissorhands), and Jimi Hendrix (Dead Presidents). Though not considered direct influences per se, Elfman has discussed his respect and admiration for film composers Jerry Goldsmith, Ennio Morricone, Thomas Newman, Alexandre Desplat and John Williams, as well as classical composer John Adams.
Though many believe Richard Wagner informed his influential score to Batman, Elfman has said it was more likely from Wagner's influence on classic film composers such as Herrmann, Steiner, Waxman and Korngold, as he was unfamiliar with Wagner's work at the time.
Elfman counts Herrmann as his biggest influence, and has said hearing Herrmann's score to The Day the Earth Stood Still when he was a child was the first time he recognized film music as a cinematic art form and realized the powerful contribution a composer makes to the movies. Pastiche of Herrmann's music can be heard in Elfman's Pee-wee's Big Adventure, especially the cues "Stolen Bike" and "Clown Dream", which directly reference Herrmann's music from Psycho and The 7th Voyage of Sinbad respectively. His score to Batman makes more subtle nods to Herrmann's Journey to the Center of the Earth and Vertigo, and more integral homage can be heard in later scores for Mars Attacks! and Hitchcock, as well as the "Blue Strings" movement of his first concert work Serenada Schizophrana.
While Elfman is primarily known for writing large-scale orchestral works in the romantic, 20th century and Hollywood Golden Age film score traditions, his compositions have used a wide range of idioms, including rock and blues (Midnight Run, Hot to Trot), big band and jazz (Dick Tracy, Chicago), operetta (The Nightmare Before Christmas, Corpse Bride), funk and hip hop (Dead Presidents, Notorious), folk and indie rock (Taking Woodstock, Silver Linings Playbook), Americana (Article 99, Sommersby, Big Fish), minimalism (Good Will Hunting, Standard Operating Procedure, The Unknown Known), and atonal or experimental (Freeway, A Simple Plan, The Girl on the Train).
Given his appreciation and study of world music and his vast collection of instruments from non-Western cultures, Elfman will often use traditional instruments in his scores when there is an international setting, such as African percussion for Instinct, the oud for The Kingdom set in Saudi Arabia, and pan flute for Proof of Life set in South America.
When working on films with established musical identifiers, Elfman will often incorporate original themes in addition to his own thematic material. Examples include Lalo Schifrin's main theme and "The Plot" from the original Mission Impossible TV Series for Mission: Impossible; John Williams' theme for Superman, the Hans Zimmer/Junkie XL theme for Wonder Woman and his own original Batman theme for Justice League; the "Welcome Christmas" song from the 1966 How the Grinch Stole Christmas! for The Grinch; and "Casey Junior," "Pink Elephants on Parade," and "When I See an Elephant Fly" from Disney's original 1941 animated film for Dumbo.
The songs for The Nightmare Before Christmas and Corpse Bride were influenced by Kurt Weill, Gilbert and Sullivan and early Rodgers and Hammerstein. At the request of Tim Burton, Charlie and the Chocolate Factory songs drew inspiration from Bollywood, the Mamas and the Papas, ABBA, and Earth, Wind & Fire individually.
Elfman's work in pop music and specifically as songwriter for Oingo Boingo was influenced by the Specials, Madness, the Selecter, Devo, Fun Boy Three, and XTC.
For his film scores, Elfman draws musical inspiration almost exclusively from viewing a cut of the film, and occasionally from visits to the set while the film is in production (he wrote and orchestrated his theme for Batman on an airplane to Los Angeles after visiting the set in London). While he prefers not to work from script, story or concept, exceptions include The Nightmare Before Christmas, for which ten songs needed to be written in advance of filmmaking, and Dumbo, for which he composed the main theme before filming began.
Once a rough cut of the film is ready, Elfman and the director have a spotting session to decide where to place music in the film, the emotional undercurrents of each scene, and overall tone. Elfman then spends a few weeks of free composition and experimentation to begin working out thematic material and to develop sounds and the harmonic palette.
When he has received approval on initial material from the filmmakers, Elfman begins to compose anywhere from 60 to 120 minutes of music cue-by-cue. He says two of the most important things to capture at this point are the tone of each scene and editorial rhythm. Next to thematic development, action set pieces tend to take Elfman the most time given the complexity of timing music to action. One element where Elfman's compositional process deviates from most film composers is that he will often compose three or more often radically different versions of a single cue to give the director more options for musicalizing a scene.
Early in his career, he wrote out his scores using pencil, but has composed largely digitally since the mid-1990s.
Before recording the score, he demos each cue by mocking orchestral and choral parts on synthesizer to get approval from the director. Once approved, he provides a detailed, multi-line sketch of his composition to his lead orchestrator Steve Bartek, who ensures the sketches are appropriately broken down for sections of the orchestra (i.e. string, brass woodwind, some percussion), choir (SATB) and individual players.
Elfman also typically samples or records his own percussion and guitar playing to overlay with live orchestra. More than half of some scores feature Elfman's performance, including Dead Presidents, Mission: Impossible, Planet of the Apes, The Kingdom, The Girl on the Train and The Circle.
To produce the score, Elfman rents a recording studio and hires a conductor and orchestra/choir. He oversees the recording from the control booth so that he can troubleshoot with the film's director and recording engineers. The final recording is given to the film's sound department to mix with dialogue and sound effects for the film's complete soundtrack. Elfman will usually do a separate mix of select cues for an album presentation of the score, and has produced nearly 100 to date.
On the occasion that there are compressed deadlines or in the event he is not available to rescore or adapt his music if there are major edits to the film after the score's completion, Elfman will hire additional composers to work on small cues or sections of cues, adapting his existing material or themes. Examples include Jonathan Sheffer on Darkman, David Buckley on the Fifty Shades films, and Pinar Toprak on Justice League. Since the 1990s, Elfman has occasionally co-composed music or shared music writing credit (e.g.When We Rise, Spy Kids, Avengers: Age of Ultron, Men in Black International), or written themes that are then used or adapted by other composers, including Jonathan Sheffer (Pure Luck), Steve Bartek (Novacaine), John Debney (Heartbreakers), Deborah Lurie (9), and the Newton Brothers (Before I Wake).
During all his career, Elfman only once collaborated with another artist – meaning writing music together: it was with Siouxsie and the Banshees on the song "Face to Face" for Batman Returns in 1992. She created the foundation of the song, "and then I would take it and I would add stuff. And send it back to her". It was a long-distance collaboration as the studio needed the song very quickly. Elfman literally saw himself as a non-collaborator. "I'm not used to collaborating at all with anybody. I did one track with Siouxsie and the Banshees but that's it. I've always been in my own bubble, and that bubble has been very fertile".
In the liner notes for the 2006 CD recording of his first concert work Serenada Schizophrana, Elfman wrote: "I began composing several dozen short improvisational compositions, maybe a minute each. Slowly, some of them began to develop themselves until finally I had six separate movements that, in some abstract, absurd way, felt connected."
To create the cadenzas for his violin concerto Eleven Eleven, Elfman collaborated with soloist Sandy Cameron, for whom the piece was written.
Elfman often incorporates choral or vocal arrangements into his film scores, notably the use of women's and children's choirs (Scrooged, Nightbreed, Edward Scissorhands, Batman Returns, Sleepy Hollow, Alice in Wonderland, The Grinch), and solo voice or vocal effects (Beetlejuice, Mars Attacks!, Men in Black II, Flubber, Nacho Libre, Iris, Dark Shadows, The Girl on the Train). Evoking the "O Fortuna" from Carl Orff's Carmina Burana, he set made-up, Latin-sounding text for SATB choir in standout cue "Descent into Mystery" from Batman.
Elfman also adds his own vocals into compositions in much the same way he mixes his percussion and guitar performances into orchestral arrangements. Prominent use can be heard in the scores for To Die For (sung with director Gus Van Sant, credited to "Little Gus and the Suzettes"), Silver Linings Playbook, and his music for the Hong Kong Disneyland ride Mystic Manor. He provided the singing voice for characters in The Nightmare Before Christmas and Corpse Bride in addition to composing the scores and songs, and can be heard singing the "Day-O" call in the style of Harry Belafonte's "Banana Boat Song" in the first bars of the Beetlejuice main title.
For Tim Burton's Charlie and the Chocolate Factory, Elfman set Roald Dahl's text for the Oompa-Loompa characters as four stylistically distinct songs: the Bollywood-influenced "Augustus Gloop", the funk-infused "Violet Beauregarde", the psychedelic pop stylings of "Veruca Salt" and the baroque rock of "Mike Teavee". For all songs in the film, Elfman sang, manipulated and mixed several layers of his vocals to create the singing voices and harmonies of the Oompa Loompas, and incorporated his vocals into non-song score tracks that featured the characters, including "Loompa Land", "Chocolate River", "The Boat Arrives" and "The River Cruise".
Elfman typically writes the lyrics to songs he has composed for movies. He employs song structures from Tin Pan Alley and early musical theatre composers (32-bar form), and pop and rock of the 1950s and 1960s (verse-chorus). As his songs serve to advance the plot and develop characters, lyrics reflect storylines and imagery specific to the film and express the inner life of characters.
He wrote the lyrics and music for ten songs featured in the stop-motion musical The Nightmare Before Christmas. Drawing from Tim Burton's parody poem of A Visit from St. Nicholas and concept drawings, Elfman wrote each song in consultation with Burton before the film even had a script. These include the full-cast songs "This Is Halloween", "Town Meeting Song" and "Making Christmas"; four songs for the main character Jack Skellington, "Jack's Lament", "What's This?", "Jack's Obsession" and "Poor Jack", all sung by Elfman; and the other character songs "Kidnap the Sandy Claws", "Oogie Boogie's Song" and "Sally's Song". An eleventh song, "Finale/Reprise", reworks lyrics from the songs "This Is Halloween", "What's This?" and "Sally's Song" for the film's ending. Though uncredited, Burton contributed some lyrics to Nightmare, including the line "Perhaps it's the head that I found in the lake" in "Town Meeting Song".
Elfman composed five songs for Burton's Corpse Bride: "According to Plan", with lyrics co-written by screenwriter John August; "Remains of the Day" (which he sung as the character Bonejangles) and "Tears to Shed", both with additional lyrics by August; and "The Wedding Song", credited solely to Elfman. The song "Erased" was not used in the final film.
He wrote the lyrics to "Lullaby" from Charlotte's Web, the rock track "The Little Things" from Wanted which he also sang in English and Russian, and "Alice's Theme" from Alice in Wonderland. Elfman co-wrote the lyrics to "Twice the Love" from Big Fish and the "Wonka's Welcome Song" for Charlie and the Chocolate Factory with John August.
Elfman wrote the lyrics to all of Oingo Boingo's original songs 1979–1994 and has made residuals on the titular two-word opening phrase sung in his The Simpsons theme since the series first aired in 1989.
As a teenager, Elfman dated his classmate Kim Gordon, who would later become one of the members of the rock band Sonic Youth. He has two daughters, Lola and Mali, from his marriage to Geri Eisenmenger. Mali is a film producer and actress. Elfman and Mali collaborated on her 2011 film Do Not Disturb.
On November 29, 2003, Elfman married actress Bridget Fonda. They have a son, Oliver. In 1998, Elfman scored A Simple Plan, starring Fonda. He is the uncle of actor Bodhi Elfman, who is married to actress Jenna Elfman.
Elfman has been an atheist since the age of 11 or 12. In an interview with the New York Post, he referred to himself as a "cynic-ologist".
Describing his politics during the 1980s, Elfman said, "I'm not a doomist. My attitude is always to be critical of what's around you, but not ever to forget how lucky we are. I've travelled around the world. I left thinking I was a revolutionary. I came back real right-wing patriotic. Since then, I've kind of mellowed in between." Several of his songs written for Oingo Boingo during this period satirised social politics, although Elfman stated his message was to "question, resist, challenge" and that his songs were not aligned to any one political agenda.
In 2008, Elfman expressed support for Barack Obama. For the 2020 Democratic National Convention, he scored the biographical video played ahead of Joe Biden's acceptance of the presidential nomination in the 2020 United States elections. In a series of posts on his Instagram page discussing the video, Elfman criticized Donald Trump, Richard Nixon, and the electoral college, and linked to several voter resources.
During his 18 years with Oingo Boingo, Elfman developed significant hearing damage as a result of the continuous exposure to the high noise levels involved in performing in a rock band. Afraid of worsening his condition, he decided to leave the band, saying that he would never return to that kind of performance. His impairment was so bad that he could not "even sit in a loud restaurant or bar anymore." However, he found performing in front of orchestras more tolerable, and returned several times to reprise his live performance of Jack Skellington.
In July 2023, Rolling Stone reported that composer Nomi Abadi had accused Elfman of sexually harassing her between 2015 and 2017. According to the magazine's reporting, Abadi and Elfman signed a non-disclosure agreement in 2018, with Elfman agreeing to pay Abadi $830,000 in installments if she did not publicize her allegations against him. Abadi stipulated that part of the settlement would help establish a nonprofit foundation, the Female Composer Safety League. When Elfman defaulted on payments to the League, Abadi filed a breach of contract suit in Los Angeles Superior Court, leading to the matter becoming public.
After Rolling Stone revealed the existence of this agreement, Elfman denied the allegations, and said that he only agreed to the settlement because he feared that his "50-year career may be destroyed in one news cycle" if the claims had been published. Elfman stated Abadi had a "childhood crush" on him and intended to break up his marriage to pursue him romantically, but that he rejected her advances, leading to the allegations. Elfman's lawyer was quoted saying "accusations alone should not and do not equate to guilt, and Danny will defend himself and clear his name with the volume of evidence and the other party's own words — her words speak for themselves."
In response, Abadi's attorney Jeff Anderson stated "It is ironic that Mr. Elfman’s current statements are directly contrary to the position he maintained in the underlying dispute and to the evidentiary record." Anderson further told Variety that "Elfman has said that his relationship to Nomi Abadi was platonic and consensual. His account is as bizarre as his conduct towards her was years ago. It was not platonic. It was bizarre."
In October 2023, a Maryland woman filed suit against Elfman for "sexual assault, gender violence, intentional infliction of emotional distress, sexual harassment and negligence." The woman, using the pseudonym Jane Doe XX, alleged that between 1997 and 2002 Elfman groomed and sexually abused her in a similar fashion to Abadi's claims.
Since The Simpsons' second annual Treehouse of Horror episode aired in 1991, launching "scary names" tradition in the opening and closing titles, Elfman has been alternately credited for the theme music as "Red Wolf Elfman", "Danny Skellingelfman", "Li'l Leakin Brain Elfman", "Boris Elfmonivich", "Danny Elfblood", "Danny 'Hell'fman", "The Bloody Elf", "Danny Elfbones" "Elfmunster" and "Daniel Beilzebelsman".
Elfman's composition "Clown Dream" from Pee-wee's Big Adventure is used in the video game Grand Theft Auto V and has often been used as the opening music for Primus concerts.
In the 2007 sixth season Star Wars parody "Blue Harvest", Family Guy lampooned Elfman's orchestral style. A scene shows Elfman replacing an incinerated John Williams to conduct a full orchestra playing the score, only to be decapitated by a lightsaber after conducting a few bars of oom-pah music.
Episode five of the 14th season of South Park in 2010 criticized Tim Burton for using the "same" music in all his films, referring to Elfman's scores.
In October 2016, Elfman produced a video clip for Funny or Die with original "horror" music composed to footage of Donald Trump pacing around Hillary Clinton at the second United States presidential election debates, 2016.
In 2019, selections from Elfman's Midnight Run score were used in the third season of Netflix's Stranger Things, including "Stairway Chase" in episodes 5 and 6, and "Wild Ride" and "Package Deal" in episode 6.
Christina Aguilera revealed that Elfman's music inspired her Las Vegas concert residency The Xperience.
Elfman's scores for Batman and Edward Scissorhands were nominated for AFI's 100 Years of Film Scores.
Including commercial recordings of his film scores and the Oingo Boingo discography, Elfman has produced over 100 albums as of 2019. | [
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"text": "Daniel Robert Elfman (born May 29, 1953) is an American film composer, singer, songwriter, and musician. He came to prominence as the lead singer and primary songwriter for the new wave band Oingo Boingo in the early 1980s. Since scoring his first studio film in 1985, Elfman has garnered international recognition for composing over 100 feature film scores, as well as compositions for television, stage productions, and the concert hall.",
"title": ""
},
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"paragraph_id": 1,
"text": "Elfman has frequently worked with directors Tim Burton, Sam Raimi, and Gus Van Sant, contributing music to nearly 20 Burton projects, including Pee-Wee's Big Adventure, Batman, Edward Scissorhands, and Wednesday, as well as scoring Raimi's Darkman, A Simple Plan, Spider-Man, Spider-Man 2 and Doctor Strange in the Multiverse of Madness, and Van Sant's Academy Award-winning films Good Will Hunting and Milk. He wrote music for all of the Men in Black and Fifty Shades of Grey franchise films, the songs and score for Henry Selick's animated musical The Nightmare Before Christmas, and the themes for the popular television series Desperate Housewives and The Simpsons.",
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{
"paragraph_id": 2,
"text": "Among his honors are four Oscar nominations, two Emmy Awards, a Grammy, seven Saturn Awards for Best Music, the 2002 Richard Kirk Award, the 2015 Disney Legend Award, the Max Steiner Film Music Achievement Award in 2017, and the Society of Composers & Lyricists Lifetime Achievement Award in 2022.",
"title": ""
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{
"paragraph_id": 3,
"text": "Elfman was born on May 29, 1953, in Los Angeles, California, to a Jewish family of Polish and Russian descent. He is a son of Blossom Elfman (née Bernstein), a writer and teacher, and Milton Elfman, a teacher, and the brother of actor, musician, and journalist Richard Elfman. Elfman was raised in a racially mixed affluent community in Baldwin Hills, California, where he spent much of his time at the local cinema discovering classic sci-fi, fantasy and horror films and first noticed the music of such film composers as Bernard Herrmann and Franz Waxman. Elfman has admitted to fabricating stories about his past out of boredom, including a false birthplace of Amarillo, Texas, and parents in the United States Air Force.",
"title": "Early life"
},
{
"paragraph_id": 4,
"text": "In his early school days, Elfman exhibited an aptitude for science with almost no interest in music, and was even rejected from elementary school orchestra \"for having no propensity for music.\" This would change when he switched high schools in the late 1960s and fell in with a musical crowd, who introduced him to early jazz and the work of Stravinsky and his 20th-century contemporaries.",
"title": "Early life"
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{
"paragraph_id": 5,
"text": "After finishing high school early with plans to travel the world, Elfman followed his brother Richard to France, where he performed violin with Jérôme Savary's Le Grand Magic Circus, an avant-garde musical theater group. He then embarked on a ten-month, self-guided tour through Africa, busking and collecting a range of West African percussion instruments until a series of illnesses forced him to return home. At this time, Richard was forming a new musical theater group in Los Angeles.",
"title": "Early life"
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{
"paragraph_id": 6,
"text": "After returning to Los Angeles from Africa in the early 1970s, Elfman was asked by his brother Richard to serve as musical director of his street theatre performance art troupe The Mystic Knights of the Oingo Boingo. Elfman was tasked with adapting and arranging 1920s and 1930s jazz and big band music by artists such as Cab Calloway, Duke Ellington, Django Reinhardt and Josephine Baker for the ensemble, which consisted of up to 15 performers playing upwards of 30 instruments. He also composed original pieces and helped build instruments unique for the group, including an aluminum gamelan, the 'Schlitz celeste' made from tuned beer cans, and a \"junkyard orchestra\" built from car parts and trash cans.",
"title": "Career"
},
{
"paragraph_id": 7,
"text": "The Mystic Knights performed on the street and in theaters, and later in nightclubs throughout Los Angeles until Richard left in 1976 to pursue filmmaking. As a send-off to the group's original concept, Richard produced the film Forbidden Zone based on the Mystic Knights' stage performances. Elfman composed the songs and his first score for the film, and appeared as the character Satan, who performs a reworked version of Calloway's \"Minnie the Moocher.\"",
"title": "Career"
},
{
"paragraph_id": 8,
"text": "Before the release of Forbidden Zone, Elfman took over the Mystic Knights as lead singer-songwriter in 1976. In 1979, he pared the group down to eight players to record and tour as a ska-influenced new wave band. That summer, the group's name would change to Oingo Boingo. Their biggest success among eight studio albums penned by Elfman was 1985's Dead Man's Party, featuring the hit song \"Weird Science\" from the movie of the same name. The band also appeared performing their single \"Dead Man's Party\" in the 1986 movie Back to School, for which Elfman also composed the score. Elfman shifted the band to a more guitar-oriented rock sound in the late 1980s, which continued through their last album Boingo in 1994.",
"title": "Career"
},
{
"paragraph_id": 9,
"text": "Citing permanent hearing damage from performing live and conflicts with his film-scoring career, Elfman retired Oingo Boingo in 1995 with a series of five sold-out final concerts at the Universal Amphitheatre ending on Halloween night. On October 31, 2015, Elfman and Oingo Boingo guitarist Steve Bartek performed the song \"Dead Man's Party\" with an orchestra as an encore to a live-to-film concert of The Nightmare Before Christmas score at the Hollywood Bowl. Elfman told the audience the performance was \"20 years to the day\" of Oingo Boingo's retirement.",
"title": "Career"
},
{
"paragraph_id": 10,
"text": "As fans of Oingo Boingo, Tim Burton and Paul Reubens invited Elfman to write the score for their first feature film Pee-wee's Big Adventure in 1985. Elfman was initially apprehensive because of his lack of formal training and having never scored a studio feature, but after Burton accepted his initial demo of the title music, and with orchestration assistance from Oingo Boingo guitarist and arranger Steve Bartek, Elfman completed the score to great effect, paying homage to influential film composers Nino Rota and Bernard Herrmann. Elfman described the first time he heard his music played by a full orchestra as one of the most thrilling experiences of his life.",
"title": "Career"
},
{
"paragraph_id": 11,
"text": "Following Pee Wee's Big Adventure, Elfman scored a string of comedies in the late 1980s, including Back to School starring Rodney Dangerfield, Burton's Beetlejuice and the Bill Murray film Scrooged. Non-comedy work included the all-synth score to Emilio Estevez's crime drama Wisdom and the big band, blues-infused music for Martin Brest's buddy cop action film Midnight Run.",
"title": "Career"
},
{
"paragraph_id": 12,
"text": "In 1989, Elfman's influential, Grammy-winning score for Burton's Batman marked a major stylistic shift to dark, densely orchestrated music in the romantic idiom. This continued in his scores for Warren Beatty's Dick Tracy, Sam Raimi's Darkman and Clive Barker's Nightbreed, all released in 1990.",
"title": "Career"
},
{
"paragraph_id": 13,
"text": "With Batman, Elfman firmly established a career-spanning relationship with Burton, scoring all but three of the director's major studio releases. Highlights include Edward Scissorhands (1990), Batman Returns (1992), Sleepy Hollow (1999), Big Fish (2003) and Alice in Wonderland (2010). In 1993, Elfman wrote the score and ten songs for the Burton-produced stop motion animated film The Nightmare Before Christmas, directed by Henry Selick, and also provided the singing voice for main character Jack Skellington, as well as the voices for secondary characters Barrel, the Clown with the Tear-Away Face and others. In 2005, he wrote the score and songs for Burton's Corpse Bride and provided the voice of the character of Bonejangles, and provided the score, songs and Oompa-Loompa vocals for Burton's Charlie and the Chocolate Factory that same year.",
"title": "Career"
},
{
"paragraph_id": 14,
"text": "In addition to frequent collaborations with Burton, Raimi and Gus Van Sant, Elfman has worked with directors such as Brian De Palma, Peter Jackson, Joss Whedon, Errol Morris, Ang Lee, Richard Donner, Guillermo del Toro, David O. Russell, Taylor Hackford, Jon Amiel, Joe Johnston, and Barry Sonnenfeld. His scores for Sonnenfeld's Men in Black, Van Sant's Good Will Hunting and Milk, and Burton's Big Fish all received Academy Award nominations.",
"title": "Career"
},
{
"paragraph_id": 15,
"text": "Since the mid-1990s, Elfman expanded his craft to a range of genres, including thrillers (Dolores Claiborne, A Simple Plan, The Kingdom, The Girl on the Train, The Woman in the Window), dramas (Sommersby, A Civil Action, Hitchcock), indies (Freeway, Silver Linings Playbook, Don't Worry, He Won't Get Far on Foot, White Noise), family (Flubber, Charlotte's Web, Frankenweenie, Goosebumps, Dolittle), documentary (Standard Operating Procedure, The Unknown Known), and horror (Red Dragon, The Wolfman), as well as entries in his well-established areas of horror comedy (The Frighteners, Mars Attacks!, Dark Shadows) and comic book-inspired action films (Hulk, Wanted, Hellboy II: The Golden Army).",
"title": "Career"
},
{
"paragraph_id": 16,
"text": "Among his franchise work, Elfman composed the scores for four Men in Black films (1997–2019) and three Fifty Shades films (2015–2018). In 1996, he scored the first film in the Mission: Impossible series, adapting themes for the original television series by Lalo Schifrin as well as composing his own. Elfman scored Raimi's Spider-Man in 2002 and Spider-Man 2 in 2004, themes and selections from which were used for Raimi's Spider-Man 3, scored by Christopher Young. Elfman's Spider-Man theme was incorporated into the MCU film Spider-Man: No Way Home composed by Michael Giacchino.",
"title": "Career"
},
{
"paragraph_id": 17,
"text": "Elfman entered the Marvel Cinematic Universe by providing additional music an 2015's Avengers: Age of Ultron, receiving composer credit with Brian Tyler. Elfman also scored MCU's Doctor Strange in the Multiverse of Madness in 2022, utilizing Giacchino's theme to the original Doctor Strange film, as well as themes from WandaVision and X-Men: The Animated Series, and music from Beethoven's Fifth Symphony and Bach's Toccata and Fugue.",
"title": "Career"
},
{
"paragraph_id": 18,
"text": "For several high-profile sequel and reboot projects in the 2010s, Elfman incorporated established musical themes with his own original thematic material, including the DC Extended Universe's Justice League, The Grinch, Dumbo and Men in Black International.",
"title": "Career"
},
{
"paragraph_id": 19,
"text": "Elfman was featured in the 2016 documentary Score, in which he appeared among over 50 film composers to discuss the craft of movie music and influential figures in the business.",
"title": "Career"
},
{
"paragraph_id": 20,
"text": "Elfman's first piece of original concert music, Serenada Schizophrana, was commissioned by the American Composers Orchestra, who premiered the piece on February 23, 2005, at Carnegie Hall. Subsequent concert works include his first Violin Concerto \"Eleven Eleven\", co-commissioned by the Czech National Symphony Orchestra, Stanford Live at Stanford University, and the Royal Scottish National Orchestra, which premiered at Smetana Hall in Prague on June 21, 2017, with Sandy Cameron on violin and John Mauceri conducting the Czech National Symphony Orchestra; the Piano Quartet, co-commissioned by the Lied Center for Performing Arts University of Nebraska and the Berlin Philharmonic Piano Quartet, which premiered February 6, 2018, in Lincoln, Nebraska; and the Percussion Quartet, commissioned by Third Coast Percussion and premiered at the Philip Glass Days And Nights Festival in Big Sur on October 10, 2019.",
"title": "Career"
},
{
"paragraph_id": 21,
"text": "2022 saw the first performances of three concert works. Elfman's Cello Concerto composed Gautier Capucon premiered by the Vienna Symphony in March, with subsequent performances by the Orchestre Philharmonique de Radio France in May and The San Francisco Symphony US premiere in November Elfman's Percussion Concerto for Colin Currie premiered at London's Royal Festival Hall with London Philharmonic Orchestra, and was later performed at Soka University of America in California, with Pacific Symphony. His Wunderkammer, a commission from the National Youth Orchestra of Great Britain, toured the UK in summer 2022, culminating in a performance in London's Royal Albert Hall as part of the BBC Proms, with national radio and TV broadcasts.",
"title": "Career"
},
{
"paragraph_id": 22,
"text": "In 2008, Elfman accepted his first commission for the stage, composing the music for Twyla Tharp's Rabbit and Rogue ballet, co-commissioned by American Ballet Theatre and Orange County Performing Arts Center and premiering on June 3, 2008, at the Metropolitan Opera House, Lincoln Center. Other works for stage include the music for Cirque Du Soleil's Iris in 2011, and incidental music for the Broadway production of Taylor Mac's Gary: A Sequel to Titus Andronicus in 2019.",
"title": "Career"
},
{
"paragraph_id": 23,
"text": "In October 2013, Elfman returned to the stage for the first time since his band Oingo Boingo disbanded to sing a handful of The Nightmare Before Christmas songs as part of the concert Danny Elfman's Music from the Films of Tim Burton, featuring suites of music from 15 Tim Burton films newly arranged by Elfman. The concert has since toured internationally and has played in Japan, Australia, Mexico and throughout Europe and the United States. Since 2015, Elfman has appeared regularly in a Hollywood Bowl Halloween concert featuring full orchestra performing the Nightmare Before Christmas score live to the film projection.",
"title": "Career"
},
{
"paragraph_id": 24,
"text": "Elfman made his Coachella debut on April 16, 2022, with Danny Elfman: From Boingo to Batman to Big Mess to Beyond! The concert, postponed from Coachella 2020 due to the COVID-19 pandemic, featured Elfman's film and television music arranged for band, orchestra and choir, as well as songs from his solo album Big Mess and new arrangements of songs from his Oingo Boingo catalogue. Conducted by Steve Bartek, and featuring Elfman (vocals, guitar, percussion), Wes Borland (guitar), Stu Brooks (bass), Nili Brosh (guitar), and Josh Freese (drums), the concert was expanded for two shows Halloween weekend 2022 at the Hollywood Bowl.",
"title": "Career"
},
{
"paragraph_id": 25,
"text": "In addition to his music for film, Elfman also penned themes for the television series The Simpsons, Tales from the Crypt, The Flash and Desperate Housewives, which won Elfman his first Emmy. He also adapted his original themes for the animated versions of Batman and Beetlejuice. Occasional forays into serial television include episodes of Alfred Hitchcock Presents, Amazing Stories and Pee-wee's Playhouse, the miniseries When We Rise co-composed with Chris Bacon, and themes for the Netflix series Wednesday.",
"title": "Career"
},
{
"paragraph_id": 26,
"text": "He has composed music for animated shorts, including Sally Cruikshank's Face Like A Frog and Tim Burton's \"Stainboy\" internet series.",
"title": "Career"
},
{
"paragraph_id": 27,
"text": "Elfman provided background music for Luigi Serafini's solo exhibition il Teatro della Pittura at the Fondazione Mudima di Milano in Milan, Italy in 1998 and for the Tim Burton exhibition at MoMA in 2009.",
"title": "Career"
},
{
"paragraph_id": 28,
"text": "In the 1990s, Elfman composed music for advertising campaigns for Nike, Nissan and Lincoln-Mercury, and in 2002 wrote the music for Honda's \"Power of Dreams\" advertising campaign, which was the first cinema commercial to be shot in the IMAX format.",
"title": "Career"
},
{
"paragraph_id": 29,
"text": "In 2013 he composed the music and provided the English-language vocals for the Hong Kong Disneyland attraction Mystic Manor.",
"title": "Career"
},
{
"paragraph_id": 30,
"text": "On October 31, 2019, the MasterClass online educational series released \"Making Music out of Chaos,\" presenting 21 compositional and career lessons from Elfman's four decades of experience primarily in the film industry.",
"title": "Career"
},
{
"paragraph_id": 31,
"text": "Elfman scored the 10-minute video \"Joe Biden,\" which introduced Joe Biden's acceptance of the presidential candidacy nomination at the 2020 Democratic National Convention.",
"title": "Career"
},
{
"paragraph_id": 32,
"text": "On November 16, 2021, Disney Branded Television announced that Elfman would compose score and songs of the upcoming Disney Television Animation and 20th Television Animation stop-motion animated comedy series \"Rhona Who Lives By The River\" created by Emily Kapnek, Elfman also serves as executive producer for the series.",
"title": "Career"
},
{
"paragraph_id": 33,
"text": "In October 2020, Elfman released the single, \"Happy,\" on Anti- Records and Epitaph Records. From January 2021 on the eleventh day of each month, he released five subsequent singles \"Sorry\", \"Love in the Time of COVID\", \"Kick Me\", \"True\", and a reworking the Oingo Boingo song \"Insects\" from the album Nothing to Fear. This culminated with the release of the double album Big Mess on June 11. Featuring 18 original songs this was Elfman's first solo studio album since 1984's So-Lo.",
"title": "Career"
},
{
"paragraph_id": 34,
"text": "On August 11, 2021, Elfman released a remix of \"True\" with lead vocals shared between Elfman and Nine Inch Nails frontman Trent Reznor. A year later, Elfman released Bigger Messier, a compilation of 23 remixes of songs on the album Big Mess by artists including Reznor, Iggy Pop, Blixa Bargeld, Squarepusher, Boy Harsher and more.",
"title": "Career"
},
{
"paragraph_id": 35,
"text": "Elfman has said his major influences are composers from Hollywood's Golden Age, such as Bernard Herrmann, Dimitri Tiomkin, Max Steiner, David Tamkin, Erich Wolfgang Korngold, and Carl Stalling; 20th century classical composers Sergei Prokofiev, Igor Stravinsky, Béla Bartók, Dmitri Shostakovich, and Carl Orff; and jazz, experimental and minimalist composers Kurt Weill, Duke Ellington, Harry Partch, Philip Glass, Lou Harrison, Terry Riley, and Steve Reich. Influences on specific scores include Erik Satie (Forbidden Zone), Nino Rota (Pee-wee's Big Adventure), George Gershwin (Dick Tracy), Pyotr Ilyich Tchaikovsky (Edward Scissorhands), and Jimi Hendrix (Dead Presidents). Though not considered direct influences per se, Elfman has discussed his respect and admiration for film composers Jerry Goldsmith, Ennio Morricone, Thomas Newman, Alexandre Desplat and John Williams, as well as classical composer John Adams.",
"title": "Influences and style"
},
{
"paragraph_id": 36,
"text": "Though many believe Richard Wagner informed his influential score to Batman, Elfman has said it was more likely from Wagner's influence on classic film composers such as Herrmann, Steiner, Waxman and Korngold, as he was unfamiliar with Wagner's work at the time.",
"title": "Influences and style"
},
{
"paragraph_id": 37,
"text": "Elfman counts Herrmann as his biggest influence, and has said hearing Herrmann's score to The Day the Earth Stood Still when he was a child was the first time he recognized film music as a cinematic art form and realized the powerful contribution a composer makes to the movies. Pastiche of Herrmann's music can be heard in Elfman's Pee-wee's Big Adventure, especially the cues \"Stolen Bike\" and \"Clown Dream\", which directly reference Herrmann's music from Psycho and The 7th Voyage of Sinbad respectively. His score to Batman makes more subtle nods to Herrmann's Journey to the Center of the Earth and Vertigo, and more integral homage can be heard in later scores for Mars Attacks! and Hitchcock, as well as the \"Blue Strings\" movement of his first concert work Serenada Schizophrana.",
"title": "Influences and style"
},
{
"paragraph_id": 38,
"text": "While Elfman is primarily known for writing large-scale orchestral works in the romantic, 20th century and Hollywood Golden Age film score traditions, his compositions have used a wide range of idioms, including rock and blues (Midnight Run, Hot to Trot), big band and jazz (Dick Tracy, Chicago), operetta (The Nightmare Before Christmas, Corpse Bride), funk and hip hop (Dead Presidents, Notorious), folk and indie rock (Taking Woodstock, Silver Linings Playbook), Americana (Article 99, Sommersby, Big Fish), minimalism (Good Will Hunting, Standard Operating Procedure, The Unknown Known), and atonal or experimental (Freeway, A Simple Plan, The Girl on the Train).",
"title": "Influences and style"
},
{
"paragraph_id": 39,
"text": "Given his appreciation and study of world music and his vast collection of instruments from non-Western cultures, Elfman will often use traditional instruments in his scores when there is an international setting, such as African percussion for Instinct, the oud for The Kingdom set in Saudi Arabia, and pan flute for Proof of Life set in South America.",
"title": "Influences and style"
},
{
"paragraph_id": 40,
"text": "When working on films with established musical identifiers, Elfman will often incorporate original themes in addition to his own thematic material. Examples include Lalo Schifrin's main theme and \"The Plot\" from the original Mission Impossible TV Series for Mission: Impossible; John Williams' theme for Superman, the Hans Zimmer/Junkie XL theme for Wonder Woman and his own original Batman theme for Justice League; the \"Welcome Christmas\" song from the 1966 How the Grinch Stole Christmas! for The Grinch; and \"Casey Junior,\" \"Pink Elephants on Parade,\" and \"When I See an Elephant Fly\" from Disney's original 1941 animated film for Dumbo.",
"title": "Influences and style"
},
{
"paragraph_id": 41,
"text": "The songs for The Nightmare Before Christmas and Corpse Bride were influenced by Kurt Weill, Gilbert and Sullivan and early Rodgers and Hammerstein. At the request of Tim Burton, Charlie and the Chocolate Factory songs drew inspiration from Bollywood, the Mamas and the Papas, ABBA, and Earth, Wind & Fire individually.",
"title": "Influences and style"
},
{
"paragraph_id": 42,
"text": "Elfman's work in pop music and specifically as songwriter for Oingo Boingo was influenced by the Specials, Madness, the Selecter, Devo, Fun Boy Three, and XTC.",
"title": "Influences and style"
},
{
"paragraph_id": 43,
"text": "For his film scores, Elfman draws musical inspiration almost exclusively from viewing a cut of the film, and occasionally from visits to the set while the film is in production (he wrote and orchestrated his theme for Batman on an airplane to Los Angeles after visiting the set in London). While he prefers not to work from script, story or concept, exceptions include The Nightmare Before Christmas, for which ten songs needed to be written in advance of filmmaking, and Dumbo, for which he composed the main theme before filming began.",
"title": "Methods"
},
{
"paragraph_id": 44,
"text": "Once a rough cut of the film is ready, Elfman and the director have a spotting session to decide where to place music in the film, the emotional undercurrents of each scene, and overall tone. Elfman then spends a few weeks of free composition and experimentation to begin working out thematic material and to develop sounds and the harmonic palette.",
"title": "Methods"
},
{
"paragraph_id": 45,
"text": "When he has received approval on initial material from the filmmakers, Elfman begins to compose anywhere from 60 to 120 minutes of music cue-by-cue. He says two of the most important things to capture at this point are the tone of each scene and editorial rhythm. Next to thematic development, action set pieces tend to take Elfman the most time given the complexity of timing music to action. One element where Elfman's compositional process deviates from most film composers is that he will often compose three or more often radically different versions of a single cue to give the director more options for musicalizing a scene.",
"title": "Methods"
},
{
"paragraph_id": 46,
"text": "Early in his career, he wrote out his scores using pencil, but has composed largely digitally since the mid-1990s.",
"title": "Methods"
},
{
"paragraph_id": 47,
"text": "Before recording the score, he demos each cue by mocking orchestral and choral parts on synthesizer to get approval from the director. Once approved, he provides a detailed, multi-line sketch of his composition to his lead orchestrator Steve Bartek, who ensures the sketches are appropriately broken down for sections of the orchestra (i.e. string, brass woodwind, some percussion), choir (SATB) and individual players.",
"title": "Methods"
},
{
"paragraph_id": 48,
"text": "Elfman also typically samples or records his own percussion and guitar playing to overlay with live orchestra. More than half of some scores feature Elfman's performance, including Dead Presidents, Mission: Impossible, Planet of the Apes, The Kingdom, The Girl on the Train and The Circle.",
"title": "Methods"
},
{
"paragraph_id": 49,
"text": "To produce the score, Elfman rents a recording studio and hires a conductor and orchestra/choir. He oversees the recording from the control booth so that he can troubleshoot with the film's director and recording engineers. The final recording is given to the film's sound department to mix with dialogue and sound effects for the film's complete soundtrack. Elfman will usually do a separate mix of select cues for an album presentation of the score, and has produced nearly 100 to date.",
"title": "Methods"
},
{
"paragraph_id": 50,
"text": "On the occasion that there are compressed deadlines or in the event he is not available to rescore or adapt his music if there are major edits to the film after the score's completion, Elfman will hire additional composers to work on small cues or sections of cues, adapting his existing material or themes. Examples include Jonathan Sheffer on Darkman, David Buckley on the Fifty Shades films, and Pinar Toprak on Justice League. Since the 1990s, Elfman has occasionally co-composed music or shared music writing credit (e.g.When We Rise, Spy Kids, Avengers: Age of Ultron, Men in Black International), or written themes that are then used or adapted by other composers, including Jonathan Sheffer (Pure Luck), Steve Bartek (Novacaine), John Debney (Heartbreakers), Deborah Lurie (9), and the Newton Brothers (Before I Wake).",
"title": "Methods"
},
{
"paragraph_id": 51,
"text": "During all his career, Elfman only once collaborated with another artist – meaning writing music together: it was with Siouxsie and the Banshees on the song \"Face to Face\" for Batman Returns in 1992. She created the foundation of the song, \"and then I would take it and I would add stuff. And send it back to her\". It was a long-distance collaboration as the studio needed the song very quickly. Elfman literally saw himself as a non-collaborator. \"I'm not used to collaborating at all with anybody. I did one track with Siouxsie and the Banshees but that's it. I've always been in my own bubble, and that bubble has been very fertile\".",
"title": "Methods"
},
{
"paragraph_id": 52,
"text": "In the liner notes for the 2006 CD recording of his first concert work Serenada Schizophrana, Elfman wrote: \"I began composing several dozen short improvisational compositions, maybe a minute each. Slowly, some of them began to develop themselves until finally I had six separate movements that, in some abstract, absurd way, felt connected.\"",
"title": "Methods"
},
{
"paragraph_id": 53,
"text": "To create the cadenzas for his violin concerto Eleven Eleven, Elfman collaborated with soloist Sandy Cameron, for whom the piece was written.",
"title": "Methods"
},
{
"paragraph_id": 54,
"text": "Elfman often incorporates choral or vocal arrangements into his film scores, notably the use of women's and children's choirs (Scrooged, Nightbreed, Edward Scissorhands, Batman Returns, Sleepy Hollow, Alice in Wonderland, The Grinch), and solo voice or vocal effects (Beetlejuice, Mars Attacks!, Men in Black II, Flubber, Nacho Libre, Iris, Dark Shadows, The Girl on the Train). Evoking the \"O Fortuna\" from Carl Orff's Carmina Burana, he set made-up, Latin-sounding text for SATB choir in standout cue \"Descent into Mystery\" from Batman.",
"title": "Methods"
},
{
"paragraph_id": 55,
"text": "Elfman also adds his own vocals into compositions in much the same way he mixes his percussion and guitar performances into orchestral arrangements. Prominent use can be heard in the scores for To Die For (sung with director Gus Van Sant, credited to \"Little Gus and the Suzettes\"), Silver Linings Playbook, and his music for the Hong Kong Disneyland ride Mystic Manor. He provided the singing voice for characters in The Nightmare Before Christmas and Corpse Bride in addition to composing the scores and songs, and can be heard singing the \"Day-O\" call in the style of Harry Belafonte's \"Banana Boat Song\" in the first bars of the Beetlejuice main title.",
"title": "Methods"
},
{
"paragraph_id": 56,
"text": "For Tim Burton's Charlie and the Chocolate Factory, Elfman set Roald Dahl's text for the Oompa-Loompa characters as four stylistically distinct songs: the Bollywood-influenced \"Augustus Gloop\", the funk-infused \"Violet Beauregarde\", the psychedelic pop stylings of \"Veruca Salt\" and the baroque rock of \"Mike Teavee\". For all songs in the film, Elfman sang, manipulated and mixed several layers of his vocals to create the singing voices and harmonies of the Oompa Loompas, and incorporated his vocals into non-song score tracks that featured the characters, including \"Loompa Land\", \"Chocolate River\", \"The Boat Arrives\" and \"The River Cruise\".",
"title": "Methods"
},
{
"paragraph_id": 57,
"text": "Elfman typically writes the lyrics to songs he has composed for movies. He employs song structures from Tin Pan Alley and early musical theatre composers (32-bar form), and pop and rock of the 1950s and 1960s (verse-chorus). As his songs serve to advance the plot and develop characters, lyrics reflect storylines and imagery specific to the film and express the inner life of characters.",
"title": "Methods"
},
{
"paragraph_id": 58,
"text": "He wrote the lyrics and music for ten songs featured in the stop-motion musical The Nightmare Before Christmas. Drawing from Tim Burton's parody poem of A Visit from St. Nicholas and concept drawings, Elfman wrote each song in consultation with Burton before the film even had a script. These include the full-cast songs \"This Is Halloween\", \"Town Meeting Song\" and \"Making Christmas\"; four songs for the main character Jack Skellington, \"Jack's Lament\", \"What's This?\", \"Jack's Obsession\" and \"Poor Jack\", all sung by Elfman; and the other character songs \"Kidnap the Sandy Claws\", \"Oogie Boogie's Song\" and \"Sally's Song\". An eleventh song, \"Finale/Reprise\", reworks lyrics from the songs \"This Is Halloween\", \"What's This?\" and \"Sally's Song\" for the film's ending. Though uncredited, Burton contributed some lyrics to Nightmare, including the line \"Perhaps it's the head that I found in the lake\" in \"Town Meeting Song\".",
"title": "Methods"
},
{
"paragraph_id": 59,
"text": "Elfman composed five songs for Burton's Corpse Bride: \"According to Plan\", with lyrics co-written by screenwriter John August; \"Remains of the Day\" (which he sung as the character Bonejangles) and \"Tears to Shed\", both with additional lyrics by August; and \"The Wedding Song\", credited solely to Elfman. The song \"Erased\" was not used in the final film.",
"title": "Methods"
},
{
"paragraph_id": 60,
"text": "He wrote the lyrics to \"Lullaby\" from Charlotte's Web, the rock track \"The Little Things\" from Wanted which he also sang in English and Russian, and \"Alice's Theme\" from Alice in Wonderland. Elfman co-wrote the lyrics to \"Twice the Love\" from Big Fish and the \"Wonka's Welcome Song\" for Charlie and the Chocolate Factory with John August.",
"title": "Methods"
},
{
"paragraph_id": 61,
"text": "Elfman wrote the lyrics to all of Oingo Boingo's original songs 1979–1994 and has made residuals on the titular two-word opening phrase sung in his The Simpsons theme since the series first aired in 1989.",
"title": "Methods"
},
{
"paragraph_id": 62,
"text": "As a teenager, Elfman dated his classmate Kim Gordon, who would later become one of the members of the rock band Sonic Youth. He has two daughters, Lola and Mali, from his marriage to Geri Eisenmenger. Mali is a film producer and actress. Elfman and Mali collaborated on her 2011 film Do Not Disturb.",
"title": "Personal life"
},
{
"paragraph_id": 63,
"text": "On November 29, 2003, Elfman married actress Bridget Fonda. They have a son, Oliver. In 1998, Elfman scored A Simple Plan, starring Fonda. He is the uncle of actor Bodhi Elfman, who is married to actress Jenna Elfman.",
"title": "Personal life"
},
{
"paragraph_id": 64,
"text": "Elfman has been an atheist since the age of 11 or 12. In an interview with the New York Post, he referred to himself as a \"cynic-ologist\".",
"title": "Personal life"
},
{
"paragraph_id": 65,
"text": "Describing his politics during the 1980s, Elfman said, \"I'm not a doomist. My attitude is always to be critical of what's around you, but not ever to forget how lucky we are. I've travelled around the world. I left thinking I was a revolutionary. I came back real right-wing patriotic. Since then, I've kind of mellowed in between.\" Several of his songs written for Oingo Boingo during this period satirised social politics, although Elfman stated his message was to \"question, resist, challenge\" and that his songs were not aligned to any one political agenda.",
"title": "Personal life"
},
{
"paragraph_id": 66,
"text": "In 2008, Elfman expressed support for Barack Obama. For the 2020 Democratic National Convention, he scored the biographical video played ahead of Joe Biden's acceptance of the presidential nomination in the 2020 United States elections. In a series of posts on his Instagram page discussing the video, Elfman criticized Donald Trump, Richard Nixon, and the electoral college, and linked to several voter resources.",
"title": "Personal life"
},
{
"paragraph_id": 67,
"text": "During his 18 years with Oingo Boingo, Elfman developed significant hearing damage as a result of the continuous exposure to the high noise levels involved in performing in a rock band. Afraid of worsening his condition, he decided to leave the band, saying that he would never return to that kind of performance. His impairment was so bad that he could not \"even sit in a loud restaurant or bar anymore.\" However, he found performing in front of orchestras more tolerable, and returned several times to reprise his live performance of Jack Skellington.",
"title": "Personal life"
},
{
"paragraph_id": 68,
"text": "In July 2023, Rolling Stone reported that composer Nomi Abadi had accused Elfman of sexually harassing her between 2015 and 2017. According to the magazine's reporting, Abadi and Elfman signed a non-disclosure agreement in 2018, with Elfman agreeing to pay Abadi $830,000 in installments if she did not publicize her allegations against him. Abadi stipulated that part of the settlement would help establish a nonprofit foundation, the Female Composer Safety League. When Elfman defaulted on payments to the League, Abadi filed a breach of contract suit in Los Angeles Superior Court, leading to the matter becoming public.",
"title": "Personal life"
},
{
"paragraph_id": 69,
"text": "After Rolling Stone revealed the existence of this agreement, Elfman denied the allegations, and said that he only agreed to the settlement because he feared that his \"50-year career may be destroyed in one news cycle\" if the claims had been published. Elfman stated Abadi had a \"childhood crush\" on him and intended to break up his marriage to pursue him romantically, but that he rejected her advances, leading to the allegations. Elfman's lawyer was quoted saying \"accusations alone should not and do not equate to guilt, and Danny will defend himself and clear his name with the volume of evidence and the other party's own words — her words speak for themselves.\"",
"title": "Personal life"
},
{
"paragraph_id": 70,
"text": "In response, Abadi's attorney Jeff Anderson stated \"It is ironic that Mr. Elfman’s current statements are directly contrary to the position he maintained in the underlying dispute and to the evidentiary record.\" Anderson further told Variety that \"Elfman has said that his relationship to Nomi Abadi was platonic and consensual. His account is as bizarre as his conduct towards her was years ago. It was not platonic. It was bizarre.\"",
"title": "Personal life"
},
{
"paragraph_id": 71,
"text": "In October 2023, a Maryland woman filed suit against Elfman for \"sexual assault, gender violence, intentional infliction of emotional distress, sexual harassment and negligence.\" The woman, using the pseudonym Jane Doe XX, alleged that between 1997 and 2002 Elfman groomed and sexually abused her in a similar fashion to Abadi's claims.",
"title": "Personal life"
},
{
"paragraph_id": 72,
"text": "Since The Simpsons' second annual Treehouse of Horror episode aired in 1991, launching \"scary names\" tradition in the opening and closing titles, Elfman has been alternately credited for the theme music as \"Red Wolf Elfman\", \"Danny Skellingelfman\", \"Li'l Leakin Brain Elfman\", \"Boris Elfmonivich\", \"Danny Elfblood\", \"Danny 'Hell'fman\", \"The Bloody Elf\", \"Danny Elfbones\" \"Elfmunster\" and \"Daniel Beilzebelsman\".",
"title": "In popular culture"
},
{
"paragraph_id": 73,
"text": "Elfman's composition \"Clown Dream\" from Pee-wee's Big Adventure is used in the video game Grand Theft Auto V and has often been used as the opening music for Primus concerts.",
"title": "In popular culture"
},
{
"paragraph_id": 74,
"text": "In the 2007 sixth season Star Wars parody \"Blue Harvest\", Family Guy lampooned Elfman's orchestral style. A scene shows Elfman replacing an incinerated John Williams to conduct a full orchestra playing the score, only to be decapitated by a lightsaber after conducting a few bars of oom-pah music.",
"title": "In popular culture"
},
{
"paragraph_id": 75,
"text": "Episode five of the 14th season of South Park in 2010 criticized Tim Burton for using the \"same\" music in all his films, referring to Elfman's scores.",
"title": "In popular culture"
},
{
"paragraph_id": 76,
"text": "In October 2016, Elfman produced a video clip for Funny or Die with original \"horror\" music composed to footage of Donald Trump pacing around Hillary Clinton at the second United States presidential election debates, 2016.",
"title": "In popular culture"
},
{
"paragraph_id": 77,
"text": "In 2019, selections from Elfman's Midnight Run score were used in the third season of Netflix's Stranger Things, including \"Stairway Chase\" in episodes 5 and 6, and \"Wild Ride\" and \"Package Deal\" in episode 6.",
"title": "In popular culture"
},
{
"paragraph_id": 78,
"text": "Christina Aguilera revealed that Elfman's music inspired her Las Vegas concert residency The Xperience.",
"title": "In popular culture"
},
{
"paragraph_id": 79,
"text": "Elfman's scores for Batman and Edward Scissorhands were nominated for AFI's 100 Years of Film Scores.",
"title": "Awards and nominations"
},
{
"paragraph_id": 80,
"text": "Including commercial recordings of his film scores and the Oingo Boingo discography, Elfman has produced over 100 albums as of 2019.",
"title": "Discography"
}
] | Daniel Robert Elfman is an American film composer, singer, songwriter, and musician. He came to prominence as the lead singer and primary songwriter for the new wave band Oingo Boingo in the early 1980s. Since scoring his first studio film in 1985, Elfman has garnered international recognition for composing over 100 feature film scores, as well as compositions for television, stage productions, and the concert hall. Elfman has frequently worked with directors Tim Burton, Sam Raimi, and Gus Van Sant, contributing music to nearly 20 Burton projects, including Pee-Wee's Big Adventure, Batman, Edward Scissorhands, and Wednesday, as well as scoring Raimi's Darkman, A Simple Plan, Spider-Man, Spider-Man 2 and Doctor Strange in the Multiverse of Madness, and Van Sant's Academy Award-winning films Good Will Hunting and Milk. He wrote music for all of the Men in Black and Fifty Shades of Grey franchise films, the songs and score for Henry Selick's animated musical The Nightmare Before Christmas, and the themes for the popular television series Desperate Housewives and The Simpsons. Among his honors are four Oscar nominations, two Emmy Awards, a Grammy, seven Saturn Awards for Best Music, the 2002 Richard Kirk Award, the 2015 Disney Legend Award, the Max Steiner Film Music Achievement Award in 2017, and the Society of Composers & Lyricists Lifetime Achievement Award in 2022. | 2001-09-05T18:20:48Z | 2023-12-17T18:07:43Z | [
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] | https://en.wikipedia.org/wiki/Danny_Elfman |
8,398 | Dimension | In physics and mathematics, the dimension of a mathematical space (or object) is informally defined as the minimum number of coordinates needed to specify any point within it. Thus, a line has a dimension of one (1D) because only one coordinate is needed to specify a point on it – for example, the point at 5 on a number line. A surface, such as the boundary of a cylinder or sphere, has a dimension of two (2D) because two coordinates are needed to specify a point on it – for example, both a latitude and longitude are required to locate a point on the surface of a sphere. A two-dimensional Euclidean space is a two-dimensional space on the plane. The inside of a cube, a cylinder or a sphere is three-dimensional (3D) because three coordinates are needed to locate a point within these spaces.
In classical mechanics, space and time are different categories and refer to absolute space and time. That conception of the world is a four-dimensional space but not the one that was found necessary to describe electromagnetism. The four dimensions (4D) of spacetime consist of events that are not absolutely defined spatially and temporally, but rather are known relative to the motion of an observer. Minkowski space first approximates the universe without gravity; the pseudo-Riemannian manifolds of general relativity describe spacetime with matter and gravity. 10 dimensions are used to describe superstring theory (6D hyperspace + 4D), 11 dimensions can describe supergravity and M-theory (7D hyperspace + 4D), and the state-space of quantum mechanics is an infinite-dimensional function space.
The concept of dimension is not restricted to physical objects. High-dimensional spaces frequently occur in mathematics and the sciences. They may be Euclidean spaces or more general parameter spaces or configuration spaces such as in Lagrangian or Hamiltonian mechanics; these are abstract spaces, independent of the physical space.
In mathematics, the dimension of an object is, roughly speaking, the number of degrees of freedom of a point that moves on this object. In other words, the dimension is the number of independent parameters or coordinates that are needed for defining the position of a point that is constrained to be on the object. For example, the dimension of a point is zero; the dimension of a line is one, as a point can move on a line in only one direction (or its opposite); the dimension of a plane is two etc.
The dimension is an intrinsic property of an object, in the sense that it is independent of the dimension of the space in which the object is or can be embedded. For example, a curve, such as a circle, is of dimension one, because the position of a point on a curve is determined by its signed distance along the curve to a fixed point on the curve. This is independent from the fact that a curve cannot be embedded in a Euclidean space of dimension lower than two, unless it is a line.
The dimension of Euclidean n-space E is n. When trying to generalize to other types of spaces, one is faced with the question "what makes E n-dimensional?" One answer is that to cover a fixed ball in E by small balls of radius ε, one needs on the order of ε such small balls. This observation leads to the definition of the Minkowski dimension and its more sophisticated variant, the Hausdorff dimension, but there are also other answers to that question. For example, the boundary of a ball in E looks locally like E and this leads to the notion of the inductive dimension. While these notions agree on E, they turn out to be different when one looks at more general spaces.
A tesseract is an example of a four-dimensional object. Whereas outside mathematics the use of the term "dimension" is as in: "A tesseract has four dimensions", mathematicians usually express this as: "The tesseract has dimension 4", or: "The dimension of the tesseract is 4" or: 4D.
Although the notion of higher dimensions goes back to René Descartes, substantial development of a higher-dimensional geometry only began in the 19th century, via the work of Arthur Cayley, William Rowan Hamilton, Ludwig Schläfli and Bernhard Riemann. Riemann's 1854 Habilitationsschrift, Schläfli's 1852 Theorie der vielfachen Kontinuität, and Hamilton's discovery of the quaternions and John T. Graves' discovery of the octonions in 1843 marked the beginning of higher-dimensional geometry.
The rest of this section examines some of the more important mathematical definitions of dimension.
The dimension of a vector space is the number of vectors in any basis for the space, i.e. the number of coordinates necessary to specify any vector. This notion of dimension (the cardinality of a basis) is often referred to as the Hamel dimension or algebraic dimension to distinguish it from other notions of dimension.
For the non-free case, this generalizes to the notion of the length of a module.
The uniquely defined dimension of every connected topological manifold can be calculated. A connected topological manifold is locally homeomorphic to Euclidean n-space, in which the number n is the manifold's dimension.
For connected differentiable manifolds, the dimension is also the dimension of the tangent vector space at any point.
In geometric topology, the theory of manifolds is characterized by the way dimensions 1 and 2 are relatively elementary, the high-dimensional cases n > 4 are simplified by having extra space in which to "work"; and the cases n = 3 and 4 are in some senses the most difficult. This state of affairs was highly marked in the various cases of the Poincaré conjecture, in which four different proof methods are applied.
The dimension of a manifold depends on the base field with respect to which Euclidean space is defined. While analysis usually assumes a manifold to be over the real numbers, it is sometimes useful in the study of complex manifolds and algebraic varieties to work over the complex numbers instead. A complex number (x + iy) has a real part x and an imaginary part y, in which x and y are both real numbers; hence, the complex dimension is half the real dimension.
Conversely, in algebraically unconstrained contexts, a single complex coordinate system may be applied to an object having two real dimensions. For example, an ordinary two-dimensional spherical surface, when given a complex metric, becomes a Riemann sphere of one complex dimension.
The dimension of an algebraic variety may be defined in various equivalent ways. The most intuitive way is probably the dimension of the tangent space at any Regular point of an algebraic variety. Another intuitive way is to define the dimension as the number of hyperplanes that are needed in order to have an intersection with the variety that is reduced to a finite number of points (dimension zero). This definition is based on the fact that the intersection of a variety with a hyperplane reduces the dimension by one unless if the hyperplane contains the variety.
An algebraic set being a finite union of algebraic varieties, its dimension is the maximum of the dimensions of its components. It is equal to the maximal length of the chains V 0 ⊊ V 1 ⊊ ⋯ ⊊ V d {\displaystyle V_{0}\subsetneq V_{1}\subsetneq \cdots \subsetneq V_{d}} of sub-varieties of the given algebraic set (the length of such a chain is the number of " ⊊ {\displaystyle \subsetneq } ").
Each variety can be considered as an algebraic stack, and its dimension as variety agrees with its dimension as stack. There are however many stacks which do not correspond to varieties, and some of these have negative dimension. Specifically, if V is a variety of dimension m and G is an algebraic group of dimension n acting on V, then the quotient stack [V/G] has dimension m − n.
The Krull dimension of a commutative ring is the maximal length of chains of prime ideals in it, a chain of length n being a sequence P 0 ⊊ P 1 ⊊ ⋯ ⊊ P n {\displaystyle {\mathcal {P}}_{0}\subsetneq {\mathcal {P}}_{1}\subsetneq \cdots \subsetneq {\mathcal {P}}_{n}} of prime ideals related by inclusion. It is strongly related to the dimension of an algebraic variety, because of the natural correspondence between sub-varieties and prime ideals of the ring of the polynomials on the variety.
For an algebra over a field, the dimension as vector space is finite if and only if its Krull dimension is 0.
For any normal topological space X, the Lebesgue covering dimension of X is defined to be the smallest integer n for which the following holds: any open cover has an open refinement (a second open cover in which each element is a subset of an element in the first cover) such that no point is included in more than n + 1 elements. In this case dim X = n. For X a manifold, this coincides with the dimension mentioned above. If no such integer n exists, then the dimension of X is said to be infinite, and one writes dim X = ∞. Moreover, X has dimension −1, i.e. dim X = −1 if and only if X is empty. This definition of covering dimension can be extended from the class of normal spaces to all Tychonoff spaces merely by replacing the term "open" in the definition by the term "functionally open".
An inductive dimension may be defined inductively as follows. Consider a discrete set of points (such as a finite collection of points) to be 0-dimensional. By dragging a 0-dimensional object in some direction, one obtains a 1-dimensional object. By dragging a 1-dimensional object in a new direction, one obtains a 2-dimensional object. In general one obtains an (n + 1)-dimensional object by dragging an n-dimensional object in a new direction. The inductive dimension of a topological space may refer to the small inductive dimension or the large inductive dimension, and is based on the analogy that, in the case of metric spaces, (n + 1)-dimensional balls have n-dimensional boundaries, permitting an inductive definition based on the dimension of the boundaries of open sets. Moreover, the boundary of a discrete set of points is the empty set, and therefore the empty set can be taken to have dimension -1.
Similarly, for the class of CW complexes, the dimension of an object is the largest n for which the n-skeleton is nontrivial. Intuitively, this can be described as follows: if the original space can be continuously deformed into a collection of higher-dimensional triangles joined at their faces with a complicated surface, then the dimension of the object is the dimension of those triangles.
The Hausdorff dimension is useful for studying structurally complicated sets, especially fractals. The Hausdorff dimension is defined for all metric spaces and, unlike the dimensions considered above, can also have non-integer real values. The box dimension or Minkowski dimension is a variant of the same idea. In general, there exist more definitions of fractal dimensions that work for highly irregular sets and attain non-integer positive real values.
Every Hilbert space admits an orthonormal basis, and any two such bases for a particular space have the same cardinality. This cardinality is called the dimension of the Hilbert space. This dimension is finite if and only if the space's Hamel dimension is finite, and in this case the two dimensions coincide.
Classical physics theories describe three physical dimensions: from a particular point in space, the basic directions in which we can move are up/down, left/right, and forward/backward. Movement in any other direction can be expressed in terms of just these three. Moving down is the same as moving up a negative distance. Moving diagonally upward and forward is just as the name of the direction implies; i.e., moving in a linear combination of up and forward. In its simplest form: a line describes one dimension, a plane describes two dimensions, and a cube describes three dimensions. (See Space and Cartesian coordinate system.)
A temporal dimension, or time dimension, is a dimension of time. Time is often referred to as the "fourth dimension" for this reason, but that is not to imply that it is a spatial dimension. A temporal dimension is one way to measure physical change. It is perceived differently from the three spatial dimensions in that there is only one of it, and that we cannot move freely in time but subjectively move in one direction.
The equations used in physics to model reality do not treat time in the same way that humans commonly perceive it. The equations of classical mechanics are symmetric with respect to time, and equations of quantum mechanics are typically symmetric if both time and other quantities (such as charge and parity) are reversed. In these models, the perception of time flowing in one direction is an artifact of the laws of thermodynamics (we perceive time as flowing in the direction of increasing entropy).
The best-known treatment of time as a dimension is Poincaré and Einstein's special relativity (and extended to general relativity), which treats perceived space and time as components of a four-dimensional manifold, known as spacetime, and in the special, flat case as Minkowski space. Time is different from other spatial dimensions as time operates in all spatial dimensions. Time operates in the first, second and third as well as theoretical spatial dimensions such as a fourth spatial dimension. Time is not however present in a single point of absolute infinite singularity as defined as a geometric point, as an infinitely small point can have no change and therefore no time. Just as when an object moves through positions in space, it also moves through positions in time. In this sense the force moving any object to change is time.
In physics, three dimensions of space and one of time is the accepted norm. However, there are theories that attempt to unify the four fundamental forces by introducing extra dimensions/hyperspace. Most notably, superstring theory requires 10 spacetime dimensions, and originates from a more fundamental 11-dimensional theory tentatively called M-theory which subsumes five previously distinct superstring theories. Supergravity theory also promotes 11D spacetime = 7D hyperspace + 4 common dimensions. To date, no direct experimental or observational evidence is available to support the existence of these extra dimensions. If hyperspace exists, it must be hidden from us by some physical mechanism. One well-studied possibility is that the extra dimensions may be "curled up" at such tiny scales as to be effectively invisible to current experiments.
In 1921, Kaluza–Klein theory presented 5D including an extra dimension of space. At the level of quantum field theory, Kaluza–Klein theory unifies gravity with gauge interactions, based on the realization that gravity propagating in small, compact extra dimensions is equivalent to gauge interactions at long distances. In particular when the geometry of the extra dimensions is trivial, it reproduces electromagnetism. However at sufficiently high energies or short distances, this setup still suffers from the same pathologies that famously obstruct direct attempts to describe quantum gravity. Therefore, these models still require a UV completion, of the kind that string theory is intended to provide. In particular, superstring theory requires six compact dimensions (6D hyperspace) forming a Calabi–Yau manifold. Thus Kaluza-Klein theory may be considered either as an incomplete description on its own, or as a subset of string theory model building.
In addition to small and curled up extra dimensions, there may be extra dimensions that instead aren't apparent because the matter associated with our visible universe is localized on a (3 + 1)-dimensional subspace. Thus the extra dimensions need not be small and compact but may be large extra dimensions. D-branes are dynamical extended objects of various dimensionalities predicted by string theory that could play this role. They have the property that open string excitations, which are associated with gauge interactions, are confined to the brane by their endpoints, whereas the closed strings that mediate the gravitational interaction are free to propagate into the whole spacetime, or "the bulk". This could be related to why gravity is exponentially weaker than the other forces, as it effectively dilutes itself as it propagates into a higher-dimensional volume.
Some aspects of brane physics have been applied to cosmology. For example, brane gas cosmology attempts to explain why there are three dimensions of space using topological and thermodynamic considerations. According to this idea it would be since three is the largest number of spatial dimensions in which strings can generically intersect. If initially there are many windings of strings around compact dimensions, space could only expand to macroscopic sizes once these windings are eliminated, which requires oppositely wound strings to find each other and annihilate. But strings can only find each other to annihilate at a meaningful rate in three dimensions, so it follows that only three dimensions of space are allowed to grow large given this kind of initial configuration.
Extra dimensions are said to be universal if all fields are equally free to propagate within them.
Several types of digital systems are based on the storage, analysis, and visualization of geometric shapes, including illustration software, Computer-aided design, and Geographic information systems. Different vector systems use a wide variety of data structures to represent shapes, but almost all are fundamentally based on a set of geometric primitives corresponding to the spatial dimensions:
Frequently in these systems, especially GIS and Cartography, a representation of a real-world phenomena may have a different (usually lower) dimension than the phenomenon being represented. For example, a city (a two-dimensional region) may be represented as a point, or a road (a three-dimensional volume of material) may be represented as a line. This dimensional generalization correlates with tendencies in spatial cognition. For example, asking the distance between two cities presumes a conceptual model of the cities as points, while giving directions involving travel "up," "down," or "along" a road imply a one-dimensional conceptual model. This is frequently done for purposes of data efficiency, visual simplicity, or cognitive efficiency, and is acceptable if the distinction between the representation and the represented is understood, but can cause confusion if information users assume that the digital shape is a perfect representation of reality (i.e., believing that roads really are lines). | [
{
"paragraph_id": 0,
"text": "In physics and mathematics, the dimension of a mathematical space (or object) is informally defined as the minimum number of coordinates needed to specify any point within it. Thus, a line has a dimension of one (1D) because only one coordinate is needed to specify a point on it – for example, the point at 5 on a number line. A surface, such as the boundary of a cylinder or sphere, has a dimension of two (2D) because two coordinates are needed to specify a point on it – for example, both a latitude and longitude are required to locate a point on the surface of a sphere. A two-dimensional Euclidean space is a two-dimensional space on the plane. The inside of a cube, a cylinder or a sphere is three-dimensional (3D) because three coordinates are needed to locate a point within these spaces.",
"title": ""
},
{
"paragraph_id": 1,
"text": "In classical mechanics, space and time are different categories and refer to absolute space and time. That conception of the world is a four-dimensional space but not the one that was found necessary to describe electromagnetism. The four dimensions (4D) of spacetime consist of events that are not absolutely defined spatially and temporally, but rather are known relative to the motion of an observer. Minkowski space first approximates the universe without gravity; the pseudo-Riemannian manifolds of general relativity describe spacetime with matter and gravity. 10 dimensions are used to describe superstring theory (6D hyperspace + 4D), 11 dimensions can describe supergravity and M-theory (7D hyperspace + 4D), and the state-space of quantum mechanics is an infinite-dimensional function space.",
"title": ""
},
{
"paragraph_id": 2,
"text": "The concept of dimension is not restricted to physical objects. High-dimensional spaces frequently occur in mathematics and the sciences. They may be Euclidean spaces or more general parameter spaces or configuration spaces such as in Lagrangian or Hamiltonian mechanics; these are abstract spaces, independent of the physical space.",
"title": ""
},
{
"paragraph_id": 3,
"text": "In mathematics, the dimension of an object is, roughly speaking, the number of degrees of freedom of a point that moves on this object. In other words, the dimension is the number of independent parameters or coordinates that are needed for defining the position of a point that is constrained to be on the object. For example, the dimension of a point is zero; the dimension of a line is one, as a point can move on a line in only one direction (or its opposite); the dimension of a plane is two etc.",
"title": "In mathematics"
},
{
"paragraph_id": 4,
"text": "The dimension is an intrinsic property of an object, in the sense that it is independent of the dimension of the space in which the object is or can be embedded. For example, a curve, such as a circle, is of dimension one, because the position of a point on a curve is determined by its signed distance along the curve to a fixed point on the curve. This is independent from the fact that a curve cannot be embedded in a Euclidean space of dimension lower than two, unless it is a line.",
"title": "In mathematics"
},
{
"paragraph_id": 5,
"text": "The dimension of Euclidean n-space E is n. When trying to generalize to other types of spaces, one is faced with the question \"what makes E n-dimensional?\" One answer is that to cover a fixed ball in E by small balls of radius ε, one needs on the order of ε such small balls. This observation leads to the definition of the Minkowski dimension and its more sophisticated variant, the Hausdorff dimension, but there are also other answers to that question. For example, the boundary of a ball in E looks locally like E and this leads to the notion of the inductive dimension. While these notions agree on E, they turn out to be different when one looks at more general spaces.",
"title": "In mathematics"
},
{
"paragraph_id": 6,
"text": "A tesseract is an example of a four-dimensional object. Whereas outside mathematics the use of the term \"dimension\" is as in: \"A tesseract has four dimensions\", mathematicians usually express this as: \"The tesseract has dimension 4\", or: \"The dimension of the tesseract is 4\" or: 4D.",
"title": "In mathematics"
},
{
"paragraph_id": 7,
"text": "Although the notion of higher dimensions goes back to René Descartes, substantial development of a higher-dimensional geometry only began in the 19th century, via the work of Arthur Cayley, William Rowan Hamilton, Ludwig Schläfli and Bernhard Riemann. Riemann's 1854 Habilitationsschrift, Schläfli's 1852 Theorie der vielfachen Kontinuität, and Hamilton's discovery of the quaternions and John T. Graves' discovery of the octonions in 1843 marked the beginning of higher-dimensional geometry.",
"title": "In mathematics"
},
{
"paragraph_id": 8,
"text": "The rest of this section examines some of the more important mathematical definitions of dimension.",
"title": "In mathematics"
},
{
"paragraph_id": 9,
"text": "The dimension of a vector space is the number of vectors in any basis for the space, i.e. the number of coordinates necessary to specify any vector. This notion of dimension (the cardinality of a basis) is often referred to as the Hamel dimension or algebraic dimension to distinguish it from other notions of dimension.",
"title": "In mathematics"
},
{
"paragraph_id": 10,
"text": "For the non-free case, this generalizes to the notion of the length of a module.",
"title": "In mathematics"
},
{
"paragraph_id": 11,
"text": "The uniquely defined dimension of every connected topological manifold can be calculated. A connected topological manifold is locally homeomorphic to Euclidean n-space, in which the number n is the manifold's dimension.",
"title": "In mathematics"
},
{
"paragraph_id": 12,
"text": "For connected differentiable manifolds, the dimension is also the dimension of the tangent vector space at any point.",
"title": "In mathematics"
},
{
"paragraph_id": 13,
"text": "In geometric topology, the theory of manifolds is characterized by the way dimensions 1 and 2 are relatively elementary, the high-dimensional cases n > 4 are simplified by having extra space in which to \"work\"; and the cases n = 3 and 4 are in some senses the most difficult. This state of affairs was highly marked in the various cases of the Poincaré conjecture, in which four different proof methods are applied.",
"title": "In mathematics"
},
{
"paragraph_id": 14,
"text": "The dimension of a manifold depends on the base field with respect to which Euclidean space is defined. While analysis usually assumes a manifold to be over the real numbers, it is sometimes useful in the study of complex manifolds and algebraic varieties to work over the complex numbers instead. A complex number (x + iy) has a real part x and an imaginary part y, in which x and y are both real numbers; hence, the complex dimension is half the real dimension.",
"title": "In mathematics"
},
{
"paragraph_id": 15,
"text": "Conversely, in algebraically unconstrained contexts, a single complex coordinate system may be applied to an object having two real dimensions. For example, an ordinary two-dimensional spherical surface, when given a complex metric, becomes a Riemann sphere of one complex dimension.",
"title": "In mathematics"
},
{
"paragraph_id": 16,
"text": "The dimension of an algebraic variety may be defined in various equivalent ways. The most intuitive way is probably the dimension of the tangent space at any Regular point of an algebraic variety. Another intuitive way is to define the dimension as the number of hyperplanes that are needed in order to have an intersection with the variety that is reduced to a finite number of points (dimension zero). This definition is based on the fact that the intersection of a variety with a hyperplane reduces the dimension by one unless if the hyperplane contains the variety.",
"title": "In mathematics"
},
{
"paragraph_id": 17,
"text": "An algebraic set being a finite union of algebraic varieties, its dimension is the maximum of the dimensions of its components. It is equal to the maximal length of the chains V 0 ⊊ V 1 ⊊ ⋯ ⊊ V d {\\displaystyle V_{0}\\subsetneq V_{1}\\subsetneq \\cdots \\subsetneq V_{d}} of sub-varieties of the given algebraic set (the length of such a chain is the number of \" ⊊ {\\displaystyle \\subsetneq } \").",
"title": "In mathematics"
},
{
"paragraph_id": 18,
"text": "Each variety can be considered as an algebraic stack, and its dimension as variety agrees with its dimension as stack. There are however many stacks which do not correspond to varieties, and some of these have negative dimension. Specifically, if V is a variety of dimension m and G is an algebraic group of dimension n acting on V, then the quotient stack [V/G] has dimension m − n.",
"title": "In mathematics"
},
{
"paragraph_id": 19,
"text": "The Krull dimension of a commutative ring is the maximal length of chains of prime ideals in it, a chain of length n being a sequence P 0 ⊊ P 1 ⊊ ⋯ ⊊ P n {\\displaystyle {\\mathcal {P}}_{0}\\subsetneq {\\mathcal {P}}_{1}\\subsetneq \\cdots \\subsetneq {\\mathcal {P}}_{n}} of prime ideals related by inclusion. It is strongly related to the dimension of an algebraic variety, because of the natural correspondence between sub-varieties and prime ideals of the ring of the polynomials on the variety.",
"title": "In mathematics"
},
{
"paragraph_id": 20,
"text": "For an algebra over a field, the dimension as vector space is finite if and only if its Krull dimension is 0.",
"title": "In mathematics"
},
{
"paragraph_id": 21,
"text": "For any normal topological space X, the Lebesgue covering dimension of X is defined to be the smallest integer n for which the following holds: any open cover has an open refinement (a second open cover in which each element is a subset of an element in the first cover) such that no point is included in more than n + 1 elements. In this case dim X = n. For X a manifold, this coincides with the dimension mentioned above. If no such integer n exists, then the dimension of X is said to be infinite, and one writes dim X = ∞. Moreover, X has dimension −1, i.e. dim X = −1 if and only if X is empty. This definition of covering dimension can be extended from the class of normal spaces to all Tychonoff spaces merely by replacing the term \"open\" in the definition by the term \"functionally open\".",
"title": "In mathematics"
},
{
"paragraph_id": 22,
"text": "An inductive dimension may be defined inductively as follows. Consider a discrete set of points (such as a finite collection of points) to be 0-dimensional. By dragging a 0-dimensional object in some direction, one obtains a 1-dimensional object. By dragging a 1-dimensional object in a new direction, one obtains a 2-dimensional object. In general one obtains an (n + 1)-dimensional object by dragging an n-dimensional object in a new direction. The inductive dimension of a topological space may refer to the small inductive dimension or the large inductive dimension, and is based on the analogy that, in the case of metric spaces, (n + 1)-dimensional balls have n-dimensional boundaries, permitting an inductive definition based on the dimension of the boundaries of open sets. Moreover, the boundary of a discrete set of points is the empty set, and therefore the empty set can be taken to have dimension -1.",
"title": "In mathematics"
},
{
"paragraph_id": 23,
"text": "Similarly, for the class of CW complexes, the dimension of an object is the largest n for which the n-skeleton is nontrivial. Intuitively, this can be described as follows: if the original space can be continuously deformed into a collection of higher-dimensional triangles joined at their faces with a complicated surface, then the dimension of the object is the dimension of those triangles.",
"title": "In mathematics"
},
{
"paragraph_id": 24,
"text": "The Hausdorff dimension is useful for studying structurally complicated sets, especially fractals. The Hausdorff dimension is defined for all metric spaces and, unlike the dimensions considered above, can also have non-integer real values. The box dimension or Minkowski dimension is a variant of the same idea. In general, there exist more definitions of fractal dimensions that work for highly irregular sets and attain non-integer positive real values.",
"title": "In mathematics"
},
{
"paragraph_id": 25,
"text": "Every Hilbert space admits an orthonormal basis, and any two such bases for a particular space have the same cardinality. This cardinality is called the dimension of the Hilbert space. This dimension is finite if and only if the space's Hamel dimension is finite, and in this case the two dimensions coincide.",
"title": "In mathematics"
},
{
"paragraph_id": 26,
"text": "Classical physics theories describe three physical dimensions: from a particular point in space, the basic directions in which we can move are up/down, left/right, and forward/backward. Movement in any other direction can be expressed in terms of just these three. Moving down is the same as moving up a negative distance. Moving diagonally upward and forward is just as the name of the direction implies; i.e., moving in a linear combination of up and forward. In its simplest form: a line describes one dimension, a plane describes two dimensions, and a cube describes three dimensions. (See Space and Cartesian coordinate system.)",
"title": "In physics"
},
{
"paragraph_id": 27,
"text": "A temporal dimension, or time dimension, is a dimension of time. Time is often referred to as the \"fourth dimension\" for this reason, but that is not to imply that it is a spatial dimension. A temporal dimension is one way to measure physical change. It is perceived differently from the three spatial dimensions in that there is only one of it, and that we cannot move freely in time but subjectively move in one direction.",
"title": "In physics"
},
{
"paragraph_id": 28,
"text": "The equations used in physics to model reality do not treat time in the same way that humans commonly perceive it. The equations of classical mechanics are symmetric with respect to time, and equations of quantum mechanics are typically symmetric if both time and other quantities (such as charge and parity) are reversed. In these models, the perception of time flowing in one direction is an artifact of the laws of thermodynamics (we perceive time as flowing in the direction of increasing entropy).",
"title": "In physics"
},
{
"paragraph_id": 29,
"text": "The best-known treatment of time as a dimension is Poincaré and Einstein's special relativity (and extended to general relativity), which treats perceived space and time as components of a four-dimensional manifold, known as spacetime, and in the special, flat case as Minkowski space. Time is different from other spatial dimensions as time operates in all spatial dimensions. Time operates in the first, second and third as well as theoretical spatial dimensions such as a fourth spatial dimension. Time is not however present in a single point of absolute infinite singularity as defined as a geometric point, as an infinitely small point can have no change and therefore no time. Just as when an object moves through positions in space, it also moves through positions in time. In this sense the force moving any object to change is time.",
"title": "In physics"
},
{
"paragraph_id": 30,
"text": "In physics, three dimensions of space and one of time is the accepted norm. However, there are theories that attempt to unify the four fundamental forces by introducing extra dimensions/hyperspace. Most notably, superstring theory requires 10 spacetime dimensions, and originates from a more fundamental 11-dimensional theory tentatively called M-theory which subsumes five previously distinct superstring theories. Supergravity theory also promotes 11D spacetime = 7D hyperspace + 4 common dimensions. To date, no direct experimental or observational evidence is available to support the existence of these extra dimensions. If hyperspace exists, it must be hidden from us by some physical mechanism. One well-studied possibility is that the extra dimensions may be \"curled up\" at such tiny scales as to be effectively invisible to current experiments.",
"title": "In physics"
},
{
"paragraph_id": 31,
"text": "In 1921, Kaluza–Klein theory presented 5D including an extra dimension of space. At the level of quantum field theory, Kaluza–Klein theory unifies gravity with gauge interactions, based on the realization that gravity propagating in small, compact extra dimensions is equivalent to gauge interactions at long distances. In particular when the geometry of the extra dimensions is trivial, it reproduces electromagnetism. However at sufficiently high energies or short distances, this setup still suffers from the same pathologies that famously obstruct direct attempts to describe quantum gravity. Therefore, these models still require a UV completion, of the kind that string theory is intended to provide. In particular, superstring theory requires six compact dimensions (6D hyperspace) forming a Calabi–Yau manifold. Thus Kaluza-Klein theory may be considered either as an incomplete description on its own, or as a subset of string theory model building.",
"title": "In physics"
},
{
"paragraph_id": 32,
"text": "In addition to small and curled up extra dimensions, there may be extra dimensions that instead aren't apparent because the matter associated with our visible universe is localized on a (3 + 1)-dimensional subspace. Thus the extra dimensions need not be small and compact but may be large extra dimensions. D-branes are dynamical extended objects of various dimensionalities predicted by string theory that could play this role. They have the property that open string excitations, which are associated with gauge interactions, are confined to the brane by their endpoints, whereas the closed strings that mediate the gravitational interaction are free to propagate into the whole spacetime, or \"the bulk\". This could be related to why gravity is exponentially weaker than the other forces, as it effectively dilutes itself as it propagates into a higher-dimensional volume.",
"title": "In physics"
},
{
"paragraph_id": 33,
"text": "Some aspects of brane physics have been applied to cosmology. For example, brane gas cosmology attempts to explain why there are three dimensions of space using topological and thermodynamic considerations. According to this idea it would be since three is the largest number of spatial dimensions in which strings can generically intersect. If initially there are many windings of strings around compact dimensions, space could only expand to macroscopic sizes once these windings are eliminated, which requires oppositely wound strings to find each other and annihilate. But strings can only find each other to annihilate at a meaningful rate in three dimensions, so it follows that only three dimensions of space are allowed to grow large given this kind of initial configuration.",
"title": "In physics"
},
{
"paragraph_id": 34,
"text": "Extra dimensions are said to be universal if all fields are equally free to propagate within them.",
"title": "In physics"
},
{
"paragraph_id": 35,
"text": "Several types of digital systems are based on the storage, analysis, and visualization of geometric shapes, including illustration software, Computer-aided design, and Geographic information systems. Different vector systems use a wide variety of data structures to represent shapes, but almost all are fundamentally based on a set of geometric primitives corresponding to the spatial dimensions:",
"title": "In computer graphics and spatial data"
},
{
"paragraph_id": 36,
"text": "Frequently in these systems, especially GIS and Cartography, a representation of a real-world phenomena may have a different (usually lower) dimension than the phenomenon being represented. For example, a city (a two-dimensional region) may be represented as a point, or a road (a three-dimensional volume of material) may be represented as a line. This dimensional generalization correlates with tendencies in spatial cognition. For example, asking the distance between two cities presumes a conceptual model of the cities as points, while giving directions involving travel \"up,\" \"down,\" or \"along\" a road imply a one-dimensional conceptual model. This is frequently done for purposes of data efficiency, visual simplicity, or cognitive efficiency, and is acceptable if the distinction between the representation and the represented is understood, but can cause confusion if information users assume that the digital shape is a perfect representation of reality (i.e., believing that roads really are lines).",
"title": "In computer graphics and spatial data"
}
] | In physics and mathematics, the dimension of a mathematical space is informally defined as the minimum number of coordinates needed to specify any point within it. Thus, a line has a dimension of one (1D) because only one coordinate is needed to specify a point on it – for example, the point at 5 on a number line. A surface, such as the boundary of a cylinder or sphere, has a dimension of two (2D) because two coordinates are needed to specify a point on it – for example, both a latitude and longitude are required to locate a point on the surface of a sphere. A two-dimensional Euclidean space is a two-dimensional space on the plane. The inside of a cube, a cylinder or a sphere is three-dimensional (3D) because three coordinates are needed to locate a point within these spaces. In classical mechanics, space and time are different categories and refer to absolute space and time. That conception of the world is a four-dimensional space but not the one that was found necessary to describe electromagnetism. The four dimensions (4D) of spacetime consist of events that are not absolutely defined spatially and temporally, but rather are known relative to the motion of an observer. Minkowski space first approximates the universe without gravity; the pseudo-Riemannian manifolds of general relativity describe spacetime with matter and gravity. 10 dimensions are used to describe superstring theory, 11 dimensions can describe supergravity and M-theory, and the state-space of quantum mechanics is an infinite-dimensional function space. The concept of dimension is not restricted to physical objects. High-dimensional spaces frequently occur in mathematics and the sciences. They may be Euclidean spaces or more general parameter spaces or configuration spaces such as in Lagrangian or Hamiltonian mechanics; these are abstract spaces, independent of the physical space. | 2001-10-07T05:01:24Z | 2023-12-22T04:46:11Z | [
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8,399 | Dissolve | Dissolve may refer to: | [
{
"paragraph_id": 0,
"text": "Dissolve may refer to:",
"title": ""
}
] | Dissolve may refer to: Dissolve (filmmaking), in film and video editing, a transition between scenes
Dissolve, a film by Kim Ki-duk
The Dissolve, a web magazine property of Pitchfork, covering movies
Dissolve (band), collaborative musical project between experimental guitarists Chris Heaphy and Roy Montgomery
"Dissolve", a song by Absofacto
‘’Dissolve’’ a song by Joji from Smithereens "Dissolve", a song by Daniel Johns from the album Talk
"Dissolve", a song by Hundred Reasons on the 2002 album Ideas Above Our Station | 2022-11-28T20:44:35Z | [
"Template:Wiktionary",
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] | https://en.wikipedia.org/wiki/Dissolve |
|
8,400 | Duodecimal | The duodecimal system (also known as base 12, or dozenal) is a positional notation numeral system using twelve as its base. The number twelve (that is, the number written as "12" in the decimal numerical system) is instead written as "10" in duodecimal (meaning "1 dozen and 0 units", instead of "1 ten and 0 units"), whereas the digit string "12" means "1 dozen and 2 units" (decimal 14). Similarly, in duodecimal, "100" means "1 gross", "1000" means "1 great gross", and "0.1" means "1 twelfth" (instead of their decimal meanings "1 hundred", "1 thousand", and "1 tenth", respectively).
Various symbols have been used to stand for ten and eleven in duodecimal notation; this page uses A and B, as in hexadecimal, which make a duodecimal count from zero to twelve read 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, A, B, 10. The Dozenal Societies of America and Great Britain (organisations promoting the use of duodecimal) use turned digits in their published material: 2 (a turned 2) for ten and 3 (a turned 3) for eleven.
The number twelve, a superior highly composite number, is the smallest number with four non-trivial factors (2, 3, 4, 6), and the smallest to include as factors all four numbers (1 to 4) within the subitizing range, and the smallest abundant number. All multiples of reciprocals of 3-smooth numbers (a/2·3 where a,b,c are integers) have a terminating representation in duodecimal. In particular, +1⁄4 (0.3), +1⁄3 (0.4), +1⁄2 (0.6), +2⁄3 (0.8), and +3⁄4 (0.9) all have a short terminating representation in duodecimal. There is also higher regularity observable in the duodecimal multiplication table. As a result, duodecimal has been described as the optimal number system.
In these respects, duodecimal is considered superior to decimal (which has only 2 and 5 as factors) and other proposed bases like octal or hexadecimal. Sexagesimal does even better in this respect (the reciprocals of all 5-smooth numbers terminate), but at the cost of unwieldy multiplication tables and a much larger number of symbols to memorize.
The origin of the duodecimal system is typically traced back to a system of finger counting based on the knuckle bones of the four larger fingers. Using the thumb as a pointer, it is possible to count to 12 by touching each finger bone, starting with the farthest bone on the fifth finger, and counting on. In this system, one hand counts repeatedly to 12, while the other displays the number of iterations, until five dozens, i.e. the 60, are full. This system is still in use in many regions of Asia.
Languages using duodecimal number systems are uncommon. Languages in the Nigerian Middle Belt such as Janji, Gbiri-Niragu (Gure-Kahugu), Piti, and the Nimbia dialect of Gwandara; and the Chepang language of Nepal are known to use duodecimal numerals.
Germanic languages have special words for 11 and 12, such as eleven and twelve in English. They come from Proto-Germanic *ainlif and *twalif (meaning, respectively, one left and two left), suggesting a decimal rather than duodecimal origin. However, Old Norse used a hybrid decimal–duodecimal counting system, with its words for "one hundred and eighty" meaning 200 and "two hundred" meaning 240. On the British Isles, this style of counting survived well into the Middle Ages as the long hundred.
Historically, units of time in many civilizations are duodecimal. There are twelve signs of the zodiac, twelve months in a year, and the Babylonians had twelve hours in a day (although at some point, this was changed to 24). Traditional Chinese calendars, clocks, and compasses are based on the twelve Earthly Branches or 24 (12×2) Solar terms. There are 12 inches in an imperial foot, 12 troy ounces in a troy pound, 12 old British pence in a shilling, 24 (12×2) hours in a day; many other items are counted by the dozen, gross (144, square of 12), or great gross (1728, cube of 12). The Romans used a fraction system based on 12, including the uncia, which became both the English words ounce and inch. Pre-decimalisation, Ireland and the United Kingdom used a mixed duodecimal-vigesimal currency system (12 pence = 1 shilling, 20 shillings or 240 pence to the pound sterling or Irish pound), and Charlemagne established a monetary system that also had a mixed base of twelve and twenty, the remnants of which persist in many places.
In a numbering system, the base (twelve for duodecimal) must be written as 10, but there are numerous proposals for how to write the quantities (counting values) "ten" and "eleven".
To allow entry on typewriters, letters such as ⟨A, B⟩ (as in hexadecimal), ⟨T, E⟩ (initials of Ten and Eleven), ⟨X, E⟩, or ⟨X, Z⟩ (X from the Roman numeral for ten) are used. Some employ Greek letters, such as ⟨δ, ε⟩ (from Greek δέκα "ten" and ένδεκα "eleven") or ⟨τ, ε⟩. Frank Emerson Andrews, an early American advocate for duodecimal, suggested and used in his 1935 book New Numbers ⟨X, Ɛ⟩ (italic capital X and a rounded italic capital E similar to open E), along with italic numerals 0–9.
Edna Kramer in her 1951 book The Main Stream of Mathematics used a ⟨*, #⟩ (sextile or six-pointed asterisk, hash or octothorpe). The symbols were chosen because they were available on some typewriters; they are also on push-button telephones. This notation was used in publications of the Dozenal Society of America (DSA) from 1974 to 2008.
From 2008 to 2015, the DSA used ⟨ , ⟩, the symbols devised by William Addison Dwiggins.
The Dozenal Society of Great Britain (DSGB) proposed symbols ⟨ 2, 3 ⟩. This notation, derived from Arabic digits by 180° rotation, was introduced by Isaac Pitman in 1857. In March 2013, a proposal was submitted to include the digit forms for ten and eleven propagated by the Dozenal Societies in the Unicode Standard. Of these, the British/Pitman forms were accepted for encoding as characters at code points U+218A ↊ TURNED DIGIT TWO and U+218B ↋ TURNED DIGIT THREE. They were included in Unicode 8.0 (2015).
After the Pitman digits were added to Unicode, the DSA took a vote and then began publishing content using the Pitman digits instead. They still use the letters X and E in ASCII text. As the Unicode characters are poorly supported, this page uses "A" and "B".
Other proposals are more creative or aesthetic; for example, many do not use any Arabic numerals under the principle of "separate identity."
There are also varying proposals of how to distinguish a duodecimal number from a decimal one. They include italicizing duodecimal numbers "54 = 64", adding a "Humphrey point" (a semicolon instead of a decimal point) to duodecimal numbers "54;6 = 64.5", or some combination of the two. Others use subscript or affixed labels to indicate the base, allowing for more than decimal and duodecimal to be represented (for single letters, "z" from "dozenal" is used, as "d" would mean decimal), such as "54z = 64d," "5412 = 6410" or "doz 54 = dec 64."
The Dozenal Society of America suggested the pronunciation of ten and eleven as "dek" and "el". For the names of powers of twelve, there are two prominent systems.
In this system, the prefix e- is added for fractions.
Multiple digits in this series are pronounced differently: 12 is "do two"; 30 is "three do"; 100 is "gro"; BA9 is "el gro dek do nine"; B86 is "el gro eight do six"; 8BB,15A is "eight gro el do el, one gro five do dek"; ABA is "dek gro el do dek"; BBB is "el gro el do el"; 0.06 is "six egro"; and so on.
This system uses "-qua" ending for the positive powers of 12 and "-cia" ending for the negative powers of 12, and an extension of the IUPAC systematic element names (with syllables dec and lev for the two extra digits needed for duodecimal) to express which power is meant.
William James Sidis used 12 as the base for his constructed language Vendergood in 1906, noting it being the smallest number with four factors and its prevalence in commerce.
The case for the duodecimal system was put forth at length in Frank Emerson Andrews' 1935 book New Numbers: How Acceptance of a Duodecimal Base Would Simplify Mathematics. Emerson noted that, due to the prevalence of factors of twelve in many traditional units of weight and measure, many of the computational advantages claimed for the metric system could be realized either by the adoption of ten-based weights and measure or by the adoption of the duodecimal number system.
Both the Dozenal Society of America and the Dozenal Society of Great Britain promote widespread adoption of the duodecimal system. They use the word "dozenal" instead of "duodecimal" to avoid the more overtly decimal terminology. However, the etymology of "dozenal" itself is also an expression based on decimal terminology since "dozen" is a direct derivation of the French word douzaine, which is a derivative of the French word for twelve, douze, descended from Latin duodecim.
Mathematician and mental calculator Alexander Craig Aitken was an outspoken advocate of duodecimal:
The duodecimal tables are easy to master, easier than the decimal ones; and in elementary teaching they would be so much more interesting, since young children would find more fascinating things to do with twelve rods or blocks than with ten. Anyone having these tables at command will do these calculations more than one-and-a-half times as fast in the duodecimal scale as in the decimal. This is my experience; I am certain that even more so it would be the experience of others.
But the final quantitative advantage, in my own experience, is this: in varied and extensive calculations of an ordinary and not unduly complicated kind, carried out over many years, I come to the conclusion that the efficiency of the decimal system might be rated at about 65 or less, if we assign 100 to the duodecimal.
In "Little Twelvetoes", American television series Schoolhouse Rock! portrayed an alien being using duodecimal arithmetic, using "dek" and "el" as names for ten and eleven, and Andrews' script-X and script-E for the digit symbols.
Systems of measurement proposed by dozenalists include:
The Dozenal Society of America argues that if a base is too small, significantly longer expansions are needed for numbers; if a base is too large, one must memorise a large multiplication table to perform arithmetic. Thus, it presumes that "a number base will need to be between about 7 or 8 through about 16, possibly including 18 and 20".
The number 12 has six factors, which are 1, 2, 3, 4, 6, and 12, of which 2 and 3 are prime. It is the smallest number to have six factors, the largest number to have at least half of the numbers below it as divisors, and is only slightly larger than 10. (The numbers 18 and 20 also have six factors but are much larger.) Ten, in contrast, only has four factors, which are 1, 2, 5, and 10, of which 2 and 5 are prime. Six shares the prime factors 2 and 3 with twelve; however, like ten, six only has four factors (1, 2, 3, and 6) instead of six. Its corresponding base, senary, is below the DSA's stated threshold.
Eight and Sixteen only have 2 as a prime factor. Therefore, in octal and hexadecimal, the only terminating fractions are those whose denominator is a power of two.
Thirty is the smallest number that has three different prime factors (2, 3, and 5, the first three primes), and it has eight factors in total (1, 2, 3, 5, 6, 10, 15, and 30). Sexagesimal was actually used by the ancient Sumerians and Babylonians, among others; its base, sixty, adds the four convenient factors 4, 12, 20, and 60 to 30 but no new prime factors. The smallest number that has four different prime factors is 210; the pattern follows the primorials. However, these numbers are quite large to use as bases, and are far beyond the DSA's stated threshold.
In all base systems, there are similarities to the representation of multiples of numbers that are one less than or one more than the base.
In the following multiplication table, numerals are written in duodecimal. For example, "10" means twelve, and "12" means fourteen.
To convert numbers between bases, one can use the general conversion algorithm (see the relevant section under positional notation). Alternatively, one can use digit-conversion tables. The ones provided below can be used to convert any duodecimal number between 0;01 and BBB,BBB;BB to decimal, or any decimal number between 0.01 and 999,999.99 to duodecimal. To use them, the given number must first be decomposed into a sum of numbers with only one significant digit each. For example:
This decomposition works the same no matter what base the number is expressed in. Just isolate each non-zero digit, padding them with as many zeros as necessary to preserve their respective place values. If the digits in the given number include zeroes (for example, 102,304.05), these are left out in the digit decomposition (102,304.05 = 100,000 + 2,000 + 300 + 4 + 0.05). Then, the digit conversion tables can be used to obtain the equivalent value in the target base for each digit. If the given number is in duodecimal and the target base is decimal, we get:
Because the summands are already converted to decimal, the usual decimal arithmetic is used to perform the addition and recompose the number, arriving at the conversion result:
That is, (duodecimal) 123,456.78 equals (decimal) 296,130.638 ≈ 296,130.64
If the given number is in decimal and the target base is duodecimal, the method is same. Using the digit conversion tables:
(decimal) 100,000 + 20,000 + 3,000 + 400 + 50 + 6 + 0.7 + 0.08 = (duodecimal) 49,A54 + B,6A8 + 1,8A0 + 294 + 42 + 6 + 0;849724972497249724972497... + 0;0B62A68781B05915343A0B62...
However, to do this sum and recompose the number, the addition tables for the duodecimal system have to be used, instead of the addition tables for decimal most people are already familiar with. This is because the summands are now in duodecimal; thus, the arithmetic with them has to be in duodecimal as well. In decimal, 6 + 6 = 12 {\displaystyle 6+6=12} ; in duodecimal, 6 + 6 = 10 {\displaystyle 6+6=10} . So, if using decimal arithmetic with duodecimal numbers, one would arrive at an incorrect result. Doing the arithmetic properly in duodecimal, one gets the result:
That is, (decimal) 123,456.78 equals (duodecimal) 5B,540;943A0B62A68781B059153... ≈ 5B,540;94
In this section, numerals are in duodecimal. For example, "10" means 6×2, and "12" means 7×2.
This section is about the divisibility rules in duodecimal.
Any integer is divisible by 1.
If a number is divisible by 2, then the unit digit of that number will be 0, 2, 4, 6, 8, or A.
If a number is divisible by 3, then the unit digit of that number will be 0, 3, 6, or 9.
If a number is divisible by 4, then the unit digit of that number will be 0, 4, or 8.
To test for divisibility by 5, double the units digit and subtract the result from the number formed by the rest of the digits. If the result is divisible by 5, then the given number is divisible by 5.
This rule comes from 21 ( 5 2 {\displaystyle 5^{2}} ).
Examples: 13 rule → | 1 − 2 × 3 | = 5 {\displaystyle |1-2\times 3|=5} , which is divisible by 5. 2BA5 rule → | 2 B A − 2 × 5 | = 2 B 0 ( 5 × 70 ) {\displaystyle |2{\texttt {B}}{\texttt {A}}-2\times 5|=2{\texttt {B}}0(5\times 70)} , which is divisible by 5 (or apply the rule on 2B0).
OR
To test for divisibility by 5, subtract the units digit and triple of the result to the number formed by the rest of the digits. If the result is divisible by 5, then the given number is divisible by 5.
This rule comes from 13 ( 5 × 3 {\displaystyle 5\times 3} ).
Examples: 13 rule → | 3 − 3 × 1 | = 0 {\displaystyle |3-3\times 1|=0} , which is divisible by 5. 2BA5 rule → | 5 − 3 × 2 B A | = 8 B 1 ( 5 × 195 ) {\displaystyle |5-3\times 2{\texttt {B}}{\texttt {A}}|=8{\texttt {B}}1(5\times 195)} , which is divisible by 5 (or apply the rule on 8B1).
OR
Form the alternating sum of blocks of two from right to left. If the result is divisible by 5, then the given number is divisible by 5.
This rule comes from 101, since 101 = 5 × 25 {\displaystyle 101=5\times 25} ; thus, this rule can be also tested for the divisibility by 25.
Example:
97,374,627 → 27 − 46 + 37 − 97 = − 7 B {\displaystyle 27-46+37-97=-7{\texttt {B}}} , which is divisible by 5.
If a number is divisible by 6, then the unit digit of that number will be 0 or 6.
To test for divisibility by 7, triple the units digit and add the result to the number formed by the rest of the digits. If the result is divisible by 7, then the given number is divisible by 7.
This rule comes from 2B ( 7 × 5 {\displaystyle 7\times 5} )
Examples: 12 rule → | 3 × 2 + 1 | = 7 {\displaystyle |3\times 2+1|=7} , which is divisible by 7. 271B rule → | 3 × B + 271 | = 29 A ( 7 × 4 A ) {\displaystyle |3\times {\texttt {B}}+271|=29{\texttt {A}}(7\times 4{\texttt {A}})} , which is divisible by 7 (or apply the rule on 29A).
OR
To test for divisibility by 7, subtract the units digit and double the result from the number formed by the rest of the digits. If the result is divisible by 7, then the given number is divisible by 7.
This rule comes from 12 ( 7 × 2 {\displaystyle 7\times 2} ).
Examples: 12 rule → | 2 − 2 × 1 | = 0 {\displaystyle |2-2\times 1|=0} , which is divisible by 7. 271B rule → | B − 2 × 271 | = 513 ( 7 × 89 ) {\displaystyle |{\texttt {B}}-2\times 271|=513(7\times 89)} , which is divisible by 7 (or apply the rule on 513).
OR
To test for divisibility by 7, quadruple the units digit and subtract the result from the number formed by the rest of the digits. If the result is divisible by 7, then the given number is divisible by 7.
This rule comes from 41 ( 7 2 {\displaystyle 7^{2}} ).
Examples: 12 rule → | 4 × 2 − 1 | = 7 {\displaystyle |4\times 2-1|=7} , which is divisible by 7. 271B rule → | 4 × B − 271 | = 235 ( 7 × 3 B ) {\displaystyle |4\times {\texttt {B}}-271|=235(7\times 3{\texttt {B}})} , which is divisible by 7 (or apply the rule on 235).
OR
Form the alternating sum of blocks of three from right to left. If the result is divisible by 7, then the given number is divisible by 7.
This rule comes from 1001, since 1001 = 7 × 11 × 17 {\displaystyle 1001=7\times 11\times 17} ; thus, this rule can be also tested for the divisibility by 11 and 17.
Example:
386,967,443 → 443 − 967 + 386 = − 168 {\displaystyle 443-967+386=-168} , which is divisible by 7.
If the two-digit number formed by the last two digits of the given number is divisible by 8, then the given number is divisible by 8.
Example: 1B48, 4120
If the two-digit number formed by the last two digits of the given number is divisible by 9, then the given number is divisible by 9.
Example: 7423, 8330
If the number is divisible by 2 and 5, then the number is divisible by A.
If the sum of the digits of a number is divisible by B, then the number is divisible by B (the equivalent of casting out nines in decimal).
Example: 29, 61B13
If a number is divisible by 10, then the unit digit of that number will be 0.
Sum the alternate digits and subtract the sums. If the result is divisible by 11, the number is divisible by 11 (the equivalent of divisibility by eleven in decimal).
Example: 66, 9427
If the number is divisible by 2 and 7, then the number is divisible by 12.
If the number is divisible by 3 and 5, then the number is divisible by 13.
If the two-digit number formed by the last two digits of the given number is divisible by 14, then the given number is divisible by 14.
Example: 1468, 7394
Duodecimal fractions for rational numbers with 3-smooth denominators terminate:
while other rational numbers have recurring duodecimal fractions:
As explained in recurring decimals, whenever an irreducible fraction is written in radix point notation in any base, the fraction can be expressed exactly (terminates) if and only if all the prime factors of its denominator are also prime factors of the base.
Because 2 × 5 = 10 {\displaystyle 2\times 5=10} in the decimal system, fractions whose denominators are made up solely of multiples of 2 and 5 terminate: 1/8 = 1/(2×2×2), 1/20 = 1/(2×2×5), and 1/500 = 1/(2×2×5×5×5) can be expressed exactly as 0.125, 0.05, and 0.002 respectively. 1/3 and 1/7, however, recur (0.333... and 0.142857142857...).
Because 2 × 2 × 3 = 12 {\displaystyle 2\times 2\times 3=12} in the duodecimal system, 1/8 is exact; 1/20 and 1/500 recur because they include 5 as a factor; 1/3 is exact, and 1/7 recurs, just as it does in decimal.
The number of denominators that give terminating fractions within a given number of digits, n, in a base b is the number of factors (divisors) of b n {\displaystyle b^{n}} , the nth power of the base b (although this includes the divisor 1, which does not produce fractions when used as the denominator). The number of factors of b n {\displaystyle b^{n}} is given using its prime factorization.
For decimal, 10 n = 2 n × 5 n {\displaystyle 10^{n}=2^{n}\times 5^{n}} . The number of divisors is found by adding one to each exponent of each prime and multiplying the resulting quantities together, so the number of factors of 10 n {\displaystyle 10^{n}} is ( n + 1 ) ( n + 1 ) = ( n + 1 ) 2 {\displaystyle (n+1)(n+1)=(n+1)^{2}} .
For example, the number 8 is a factor of 10 (1000), so 1 8 {\textstyle {\frac {1}{8}}} and other fractions with a denominator of 8 cannot require more than three fractional decimal digits to terminate. 5 8 = 0.625 10 . {\textstyle {\frac {5}{8}}=0.625_{10}.}
For duodecimal, 10 n = 2 2 n × 3 n {\displaystyle 10^{n}=2^{2n}\times 3^{n}} . This has ( 2 n + 1 ) ( n + 1 ) {\displaystyle (2n+1)(n+1)} divisors. The sample denominator of 8 is a factor of a gross 12 2 = 144 {\textstyle 12^{2}=144} in decimal), so eighths cannot need more than two duodecimal fractional places to terminate. 5 8 = 0.76 12 . {\textstyle {\frac {5}{8}}=0.76_{12}.}
Because both ten and twelve have two unique prime factors, the number of divisors of b n {\displaystyle b^{n}} for b = 10 or 12 grows quadratically with the exponent n (in other words, of the order of n 2 {\displaystyle n^{2}} ).
The Dozenal Society of America argues that factors of 3 are more commonly encountered in real-life division problems than factors of 5. Thus, in practical applications, the nuisance of repeating decimals is encountered less often when duodecimal notation is used. Advocates of duodecimal systems argue that this is particularly true of financial calculations, in which the twelve months of the year often enter into calculations.
However, when recurring fractions do occur in duodecimal notation, they are less likely to have a very short period than in decimal notation, because 12 (twelve) is between two prime numbers, 11 (eleven) and 13 (thirteen), whereas ten is adjacent to the composite number 9. Nonetheless, having a shorter or longer period does not help the main inconvenience that one does not get a finite representation for such fractions in the given base (so rounding, which introduces inexactitude, is necessary to handle them in calculations), and overall one is more likely to have to deal with infinite recurring digits when fractions are expressed in decimal than in duodecimal, because one out of every three consecutive numbers contains the prime factor 3 in its factorization, whereas only one out of every five contains the prime factor 5. All other prime factors, except 2, are not shared by either ten or twelve, so they do not influence the relative likeliness of encountering recurring digits (any irreducible fraction that contains any of these other factors in its denominator will recur in either base).
Also, the prime factor 2 appears twice in the factorization of twelve, whereas only once in the factorization of ten; which means that most fractions whose denominators are powers of two will have a shorter, more convenient terminating representation in duodecimal than in decimal:
The duodecimal period length of 1/n are (in decimal)
The duodecimal period length of 1/(nth prime) are (in decimal)
Smallest prime with duodecimal period n are (in decimal)
The representations of irrational numbers in any positional number system (including decimal and duodecimal) neither terminate nor repeat. The following table gives the first digits for some important algebraic and transcendental numbers in both decimal and duodecimal. | [
{
"paragraph_id": 0,
"text": "The duodecimal system (also known as base 12, or dozenal) is a positional notation numeral system using twelve as its base. The number twelve (that is, the number written as \"12\" in the decimal numerical system) is instead written as \"10\" in duodecimal (meaning \"1 dozen and 0 units\", instead of \"1 ten and 0 units\"), whereas the digit string \"12\" means \"1 dozen and 2 units\" (decimal 14). Similarly, in duodecimal, \"100\" means \"1 gross\", \"1000\" means \"1 great gross\", and \"0.1\" means \"1 twelfth\" (instead of their decimal meanings \"1 hundred\", \"1 thousand\", and \"1 tenth\", respectively).",
"title": ""
},
{
"paragraph_id": 1,
"text": "Various symbols have been used to stand for ten and eleven in duodecimal notation; this page uses A and B, as in hexadecimal, which make a duodecimal count from zero to twelve read 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, A, B, 10. The Dozenal Societies of America and Great Britain (organisations promoting the use of duodecimal) use turned digits in their published material: 2 (a turned 2) for ten and 3 (a turned 3) for eleven.",
"title": ""
},
{
"paragraph_id": 2,
"text": "The number twelve, a superior highly composite number, is the smallest number with four non-trivial factors (2, 3, 4, 6), and the smallest to include as factors all four numbers (1 to 4) within the subitizing range, and the smallest abundant number. All multiples of reciprocals of 3-smooth numbers (a/2·3 where a,b,c are integers) have a terminating representation in duodecimal. In particular, +1⁄4 (0.3), +1⁄3 (0.4), +1⁄2 (0.6), +2⁄3 (0.8), and +3⁄4 (0.9) all have a short terminating representation in duodecimal. There is also higher regularity observable in the duodecimal multiplication table. As a result, duodecimal has been described as the optimal number system.",
"title": ""
},
{
"paragraph_id": 3,
"text": "In these respects, duodecimal is considered superior to decimal (which has only 2 and 5 as factors) and other proposed bases like octal or hexadecimal. Sexagesimal does even better in this respect (the reciprocals of all 5-smooth numbers terminate), but at the cost of unwieldy multiplication tables and a much larger number of symbols to memorize.",
"title": ""
},
{
"paragraph_id": 4,
"text": "The origin of the duodecimal system is typically traced back to a system of finger counting based on the knuckle bones of the four larger fingers. Using the thumb as a pointer, it is possible to count to 12 by touching each finger bone, starting with the farthest bone on the fifth finger, and counting on. In this system, one hand counts repeatedly to 12, while the other displays the number of iterations, until five dozens, i.e. the 60, are full. This system is still in use in many regions of Asia.",
"title": "Origin"
},
{
"paragraph_id": 5,
"text": "Languages using duodecimal number systems are uncommon. Languages in the Nigerian Middle Belt such as Janji, Gbiri-Niragu (Gure-Kahugu), Piti, and the Nimbia dialect of Gwandara; and the Chepang language of Nepal are known to use duodecimal numerals.",
"title": "Origin"
},
{
"paragraph_id": 6,
"text": "Germanic languages have special words for 11 and 12, such as eleven and twelve in English. They come from Proto-Germanic *ainlif and *twalif (meaning, respectively, one left and two left), suggesting a decimal rather than duodecimal origin. However, Old Norse used a hybrid decimal–duodecimal counting system, with its words for \"one hundred and eighty\" meaning 200 and \"two hundred\" meaning 240. On the British Isles, this style of counting survived well into the Middle Ages as the long hundred.",
"title": "Origin"
},
{
"paragraph_id": 7,
"text": "Historically, units of time in many civilizations are duodecimal. There are twelve signs of the zodiac, twelve months in a year, and the Babylonians had twelve hours in a day (although at some point, this was changed to 24). Traditional Chinese calendars, clocks, and compasses are based on the twelve Earthly Branches or 24 (12×2) Solar terms. There are 12 inches in an imperial foot, 12 troy ounces in a troy pound, 12 old British pence in a shilling, 24 (12×2) hours in a day; many other items are counted by the dozen, gross (144, square of 12), or great gross (1728, cube of 12). The Romans used a fraction system based on 12, including the uncia, which became both the English words ounce and inch. Pre-decimalisation, Ireland and the United Kingdom used a mixed duodecimal-vigesimal currency system (12 pence = 1 shilling, 20 shillings or 240 pence to the pound sterling or Irish pound), and Charlemagne established a monetary system that also had a mixed base of twelve and twenty, the remnants of which persist in many places.",
"title": "Origin"
},
{
"paragraph_id": 8,
"text": "In a numbering system, the base (twelve for duodecimal) must be written as 10, but there are numerous proposals for how to write the quantities (counting values) \"ten\" and \"eleven\".",
"title": "Notations and pronunciations"
},
{
"paragraph_id": 9,
"text": "To allow entry on typewriters, letters such as ⟨A, B⟩ (as in hexadecimal), ⟨T, E⟩ (initials of Ten and Eleven), ⟨X, E⟩, or ⟨X, Z⟩ (X from the Roman numeral for ten) are used. Some employ Greek letters, such as ⟨δ, ε⟩ (from Greek δέκα \"ten\" and ένδεκα \"eleven\") or ⟨τ, ε⟩. Frank Emerson Andrews, an early American advocate for duodecimal, suggested and used in his 1935 book New Numbers ⟨X, Ɛ⟩ (italic capital X and a rounded italic capital E similar to open E), along with italic numerals 0–9.",
"title": "Notations and pronunciations"
},
{
"paragraph_id": 10,
"text": "Edna Kramer in her 1951 book The Main Stream of Mathematics used a ⟨*, #⟩ (sextile or six-pointed asterisk, hash or octothorpe). The symbols were chosen because they were available on some typewriters; they are also on push-button telephones. This notation was used in publications of the Dozenal Society of America (DSA) from 1974 to 2008.",
"title": "Notations and pronunciations"
},
{
"paragraph_id": 11,
"text": "From 2008 to 2015, the DSA used ⟨ , ⟩, the symbols devised by William Addison Dwiggins.",
"title": "Notations and pronunciations"
},
{
"paragraph_id": 12,
"text": "The Dozenal Society of Great Britain (DSGB) proposed symbols ⟨ 2, 3 ⟩. This notation, derived from Arabic digits by 180° rotation, was introduced by Isaac Pitman in 1857. In March 2013, a proposal was submitted to include the digit forms for ten and eleven propagated by the Dozenal Societies in the Unicode Standard. Of these, the British/Pitman forms were accepted for encoding as characters at code points U+218A ↊ TURNED DIGIT TWO and U+218B ↋ TURNED DIGIT THREE. They were included in Unicode 8.0 (2015).",
"title": "Notations and pronunciations"
},
{
"paragraph_id": 13,
"text": "After the Pitman digits were added to Unicode, the DSA took a vote and then began publishing content using the Pitman digits instead. They still use the letters X and E in ASCII text. As the Unicode characters are poorly supported, this page uses \"A\" and \"B\".",
"title": "Notations and pronunciations"
},
{
"paragraph_id": 14,
"text": "Other proposals are more creative or aesthetic; for example, many do not use any Arabic numerals under the principle of \"separate identity.\"",
"title": "Notations and pronunciations"
},
{
"paragraph_id": 15,
"text": "There are also varying proposals of how to distinguish a duodecimal number from a decimal one. They include italicizing duodecimal numbers \"54 = 64\", adding a \"Humphrey point\" (a semicolon instead of a decimal point) to duodecimal numbers \"54;6 = 64.5\", or some combination of the two. Others use subscript or affixed labels to indicate the base, allowing for more than decimal and duodecimal to be represented (for single letters, \"z\" from \"dozenal\" is used, as \"d\" would mean decimal), such as \"54z = 64d,\" \"5412 = 6410\" or \"doz 54 = dec 64.\"",
"title": "Notations and pronunciations"
},
{
"paragraph_id": 16,
"text": "The Dozenal Society of America suggested the pronunciation of ten and eleven as \"dek\" and \"el\". For the names of powers of twelve, there are two prominent systems.",
"title": "Notations and pronunciations"
},
{
"paragraph_id": 17,
"text": "In this system, the prefix e- is added for fractions.",
"title": "Notations and pronunciations"
},
{
"paragraph_id": 18,
"text": "Multiple digits in this series are pronounced differently: 12 is \"do two\"; 30 is \"three do\"; 100 is \"gro\"; BA9 is \"el gro dek do nine\"; B86 is \"el gro eight do six\"; 8BB,15A is \"eight gro el do el, one gro five do dek\"; ABA is \"dek gro el do dek\"; BBB is \"el gro el do el\"; 0.06 is \"six egro\"; and so on.",
"title": "Notations and pronunciations"
},
{
"paragraph_id": 19,
"text": "This system uses \"-qua\" ending for the positive powers of 12 and \"-cia\" ending for the negative powers of 12, and an extension of the IUPAC systematic element names (with syllables dec and lev for the two extra digits needed for duodecimal) to express which power is meant.",
"title": "Notations and pronunciations"
},
{
"paragraph_id": 20,
"text": "William James Sidis used 12 as the base for his constructed language Vendergood in 1906, noting it being the smallest number with four factors and its prevalence in commerce.",
"title": "Advocacy and \"dozenalism\""
},
{
"paragraph_id": 21,
"text": "The case for the duodecimal system was put forth at length in Frank Emerson Andrews' 1935 book New Numbers: How Acceptance of a Duodecimal Base Would Simplify Mathematics. Emerson noted that, due to the prevalence of factors of twelve in many traditional units of weight and measure, many of the computational advantages claimed for the metric system could be realized either by the adoption of ten-based weights and measure or by the adoption of the duodecimal number system.",
"title": "Advocacy and \"dozenalism\""
},
{
"paragraph_id": 22,
"text": "Both the Dozenal Society of America and the Dozenal Society of Great Britain promote widespread adoption of the duodecimal system. They use the word \"dozenal\" instead of \"duodecimal\" to avoid the more overtly decimal terminology. However, the etymology of \"dozenal\" itself is also an expression based on decimal terminology since \"dozen\" is a direct derivation of the French word douzaine, which is a derivative of the French word for twelve, douze, descended from Latin duodecim.",
"title": "Advocacy and \"dozenalism\""
},
{
"paragraph_id": 23,
"text": "Mathematician and mental calculator Alexander Craig Aitken was an outspoken advocate of duodecimal:",
"title": "Advocacy and \"dozenalism\""
},
{
"paragraph_id": 24,
"text": "The duodecimal tables are easy to master, easier than the decimal ones; and in elementary teaching they would be so much more interesting, since young children would find more fascinating things to do with twelve rods or blocks than with ten. Anyone having these tables at command will do these calculations more than one-and-a-half times as fast in the duodecimal scale as in the decimal. This is my experience; I am certain that even more so it would be the experience of others.",
"title": "Advocacy and \"dozenalism\""
},
{
"paragraph_id": 25,
"text": "But the final quantitative advantage, in my own experience, is this: in varied and extensive calculations of an ordinary and not unduly complicated kind, carried out over many years, I come to the conclusion that the efficiency of the decimal system might be rated at about 65 or less, if we assign 100 to the duodecimal.",
"title": "Advocacy and \"dozenalism\""
},
{
"paragraph_id": 26,
"text": "In \"Little Twelvetoes\", American television series Schoolhouse Rock! portrayed an alien being using duodecimal arithmetic, using \"dek\" and \"el\" as names for ten and eleven, and Andrews' script-X and script-E for the digit symbols.",
"title": "Advocacy and \"dozenalism\""
},
{
"paragraph_id": 27,
"text": "Systems of measurement proposed by dozenalists include:",
"title": "Advocacy and \"dozenalism\""
},
{
"paragraph_id": 28,
"text": "The Dozenal Society of America argues that if a base is too small, significantly longer expansions are needed for numbers; if a base is too large, one must memorise a large multiplication table to perform arithmetic. Thus, it presumes that \"a number base will need to be between about 7 or 8 through about 16, possibly including 18 and 20\".",
"title": "Comparison to other number systems"
},
{
"paragraph_id": 29,
"text": "The number 12 has six factors, which are 1, 2, 3, 4, 6, and 12, of which 2 and 3 are prime. It is the smallest number to have six factors, the largest number to have at least half of the numbers below it as divisors, and is only slightly larger than 10. (The numbers 18 and 20 also have six factors but are much larger.) Ten, in contrast, only has four factors, which are 1, 2, 5, and 10, of which 2 and 5 are prime. Six shares the prime factors 2 and 3 with twelve; however, like ten, six only has four factors (1, 2, 3, and 6) instead of six. Its corresponding base, senary, is below the DSA's stated threshold.",
"title": "Comparison to other number systems"
},
{
"paragraph_id": 30,
"text": "Eight and Sixteen only have 2 as a prime factor. Therefore, in octal and hexadecimal, the only terminating fractions are those whose denominator is a power of two.",
"title": "Comparison to other number systems"
},
{
"paragraph_id": 31,
"text": "Thirty is the smallest number that has three different prime factors (2, 3, and 5, the first three primes), and it has eight factors in total (1, 2, 3, 5, 6, 10, 15, and 30). Sexagesimal was actually used by the ancient Sumerians and Babylonians, among others; its base, sixty, adds the four convenient factors 4, 12, 20, and 60 to 30 but no new prime factors. The smallest number that has four different prime factors is 210; the pattern follows the primorials. However, these numbers are quite large to use as bases, and are far beyond the DSA's stated threshold.",
"title": "Comparison to other number systems"
},
{
"paragraph_id": 32,
"text": "In all base systems, there are similarities to the representation of multiples of numbers that are one less than or one more than the base.",
"title": "Comparison to other number systems"
},
{
"paragraph_id": 33,
"text": "In the following multiplication table, numerals are written in duodecimal. For example, \"10\" means twelve, and \"12\" means fourteen.",
"title": "Comparison to other number systems"
},
{
"paragraph_id": 34,
"text": "To convert numbers between bases, one can use the general conversion algorithm (see the relevant section under positional notation). Alternatively, one can use digit-conversion tables. The ones provided below can be used to convert any duodecimal number between 0;01 and BBB,BBB;BB to decimal, or any decimal number between 0.01 and 999,999.99 to duodecimal. To use them, the given number must first be decomposed into a sum of numbers with only one significant digit each. For example:",
"title": "Conversion tables to and from decimal"
},
{
"paragraph_id": 35,
"text": "This decomposition works the same no matter what base the number is expressed in. Just isolate each non-zero digit, padding them with as many zeros as necessary to preserve their respective place values. If the digits in the given number include zeroes (for example, 102,304.05), these are left out in the digit decomposition (102,304.05 = 100,000 + 2,000 + 300 + 4 + 0.05). Then, the digit conversion tables can be used to obtain the equivalent value in the target base for each digit. If the given number is in duodecimal and the target base is decimal, we get:",
"title": "Conversion tables to and from decimal"
},
{
"paragraph_id": 36,
"text": "Because the summands are already converted to decimal, the usual decimal arithmetic is used to perform the addition and recompose the number, arriving at the conversion result:",
"title": "Conversion tables to and from decimal"
},
{
"paragraph_id": 37,
"text": "That is, (duodecimal) 123,456.78 equals (decimal) 296,130.638 ≈ 296,130.64",
"title": "Conversion tables to and from decimal"
},
{
"paragraph_id": 38,
"text": "If the given number is in decimal and the target base is duodecimal, the method is same. Using the digit conversion tables:",
"title": "Conversion tables to and from decimal"
},
{
"paragraph_id": 39,
"text": "(decimal) 100,000 + 20,000 + 3,000 + 400 + 50 + 6 + 0.7 + 0.08 = (duodecimal) 49,A54 + B,6A8 + 1,8A0 + 294 + 42 + 6 + 0;849724972497249724972497... + 0;0B62A68781B05915343A0B62...",
"title": "Conversion tables to and from decimal"
},
{
"paragraph_id": 40,
"text": "However, to do this sum and recompose the number, the addition tables for the duodecimal system have to be used, instead of the addition tables for decimal most people are already familiar with. This is because the summands are now in duodecimal; thus, the arithmetic with them has to be in duodecimal as well. In decimal, 6 + 6 = 12 {\\displaystyle 6+6=12} ; in duodecimal, 6 + 6 = 10 {\\displaystyle 6+6=10} . So, if using decimal arithmetic with duodecimal numbers, one would arrive at an incorrect result. Doing the arithmetic properly in duodecimal, one gets the result:",
"title": "Conversion tables to and from decimal"
},
{
"paragraph_id": 41,
"text": "That is, (decimal) 123,456.78 equals (duodecimal) 5B,540;943A0B62A68781B059153... ≈ 5B,540;94",
"title": "Conversion tables to and from decimal"
},
{
"paragraph_id": 42,
"text": "In this section, numerals are in duodecimal. For example, \"10\" means 6×2, and \"12\" means 7×2.",
"title": "Divisibility rules"
},
{
"paragraph_id": 43,
"text": "This section is about the divisibility rules in duodecimal.",
"title": "Divisibility rules"
},
{
"paragraph_id": 44,
"text": "Any integer is divisible by 1.",
"title": "Divisibility rules"
},
{
"paragraph_id": 45,
"text": "If a number is divisible by 2, then the unit digit of that number will be 0, 2, 4, 6, 8, or A.",
"title": "Divisibility rules"
},
{
"paragraph_id": 46,
"text": "If a number is divisible by 3, then the unit digit of that number will be 0, 3, 6, or 9.",
"title": "Divisibility rules"
},
{
"paragraph_id": 47,
"text": "If a number is divisible by 4, then the unit digit of that number will be 0, 4, or 8.",
"title": "Divisibility rules"
},
{
"paragraph_id": 48,
"text": "To test for divisibility by 5, double the units digit and subtract the result from the number formed by the rest of the digits. If the result is divisible by 5, then the given number is divisible by 5.",
"title": "Divisibility rules"
},
{
"paragraph_id": 49,
"text": "This rule comes from 21 ( 5 2 {\\displaystyle 5^{2}} ).",
"title": "Divisibility rules"
},
{
"paragraph_id": 50,
"text": "Examples: 13 rule → | 1 − 2 × 3 | = 5 {\\displaystyle |1-2\\times 3|=5} , which is divisible by 5. 2BA5 rule → | 2 B A − 2 × 5 | = 2 B 0 ( 5 × 70 ) {\\displaystyle |2{\\texttt {B}}{\\texttt {A}}-2\\times 5|=2{\\texttt {B}}0(5\\times 70)} , which is divisible by 5 (or apply the rule on 2B0).",
"title": "Divisibility rules"
},
{
"paragraph_id": 51,
"text": "OR",
"title": "Divisibility rules"
},
{
"paragraph_id": 52,
"text": "To test for divisibility by 5, subtract the units digit and triple of the result to the number formed by the rest of the digits. If the result is divisible by 5, then the given number is divisible by 5.",
"title": "Divisibility rules"
},
{
"paragraph_id": 53,
"text": "This rule comes from 13 ( 5 × 3 {\\displaystyle 5\\times 3} ).",
"title": "Divisibility rules"
},
{
"paragraph_id": 54,
"text": "Examples: 13 rule → | 3 − 3 × 1 | = 0 {\\displaystyle |3-3\\times 1|=0} , which is divisible by 5. 2BA5 rule → | 5 − 3 × 2 B A | = 8 B 1 ( 5 × 195 ) {\\displaystyle |5-3\\times 2{\\texttt {B}}{\\texttt {A}}|=8{\\texttt {B}}1(5\\times 195)} , which is divisible by 5 (or apply the rule on 8B1).",
"title": "Divisibility rules"
},
{
"paragraph_id": 55,
"text": "OR",
"title": "Divisibility rules"
},
{
"paragraph_id": 56,
"text": "Form the alternating sum of blocks of two from right to left. If the result is divisible by 5, then the given number is divisible by 5.",
"title": "Divisibility rules"
},
{
"paragraph_id": 57,
"text": "This rule comes from 101, since 101 = 5 × 25 {\\displaystyle 101=5\\times 25} ; thus, this rule can be also tested for the divisibility by 25.",
"title": "Divisibility rules"
},
{
"paragraph_id": 58,
"text": "Example:",
"title": "Divisibility rules"
},
{
"paragraph_id": 59,
"text": "97,374,627 → 27 − 46 + 37 − 97 = − 7 B {\\displaystyle 27-46+37-97=-7{\\texttt {B}}} , which is divisible by 5.",
"title": "Divisibility rules"
},
{
"paragraph_id": 60,
"text": "If a number is divisible by 6, then the unit digit of that number will be 0 or 6.",
"title": "Divisibility rules"
},
{
"paragraph_id": 61,
"text": "To test for divisibility by 7, triple the units digit and add the result to the number formed by the rest of the digits. If the result is divisible by 7, then the given number is divisible by 7.",
"title": "Divisibility rules"
},
{
"paragraph_id": 62,
"text": "This rule comes from 2B ( 7 × 5 {\\displaystyle 7\\times 5} )",
"title": "Divisibility rules"
},
{
"paragraph_id": 63,
"text": "Examples: 12 rule → | 3 × 2 + 1 | = 7 {\\displaystyle |3\\times 2+1|=7} , which is divisible by 7. 271B rule → | 3 × B + 271 | = 29 A ( 7 × 4 A ) {\\displaystyle |3\\times {\\texttt {B}}+271|=29{\\texttt {A}}(7\\times 4{\\texttt {A}})} , which is divisible by 7 (or apply the rule on 29A).",
"title": "Divisibility rules"
},
{
"paragraph_id": 64,
"text": "OR",
"title": "Divisibility rules"
},
{
"paragraph_id": 65,
"text": "To test for divisibility by 7, subtract the units digit and double the result from the number formed by the rest of the digits. If the result is divisible by 7, then the given number is divisible by 7.",
"title": "Divisibility rules"
},
{
"paragraph_id": 66,
"text": "This rule comes from 12 ( 7 × 2 {\\displaystyle 7\\times 2} ).",
"title": "Divisibility rules"
},
{
"paragraph_id": 67,
"text": "Examples: 12 rule → | 2 − 2 × 1 | = 0 {\\displaystyle |2-2\\times 1|=0} , which is divisible by 7. 271B rule → | B − 2 × 271 | = 513 ( 7 × 89 ) {\\displaystyle |{\\texttt {B}}-2\\times 271|=513(7\\times 89)} , which is divisible by 7 (or apply the rule on 513).",
"title": "Divisibility rules"
},
{
"paragraph_id": 68,
"text": "OR",
"title": "Divisibility rules"
},
{
"paragraph_id": 69,
"text": "To test for divisibility by 7, quadruple the units digit and subtract the result from the number formed by the rest of the digits. If the result is divisible by 7, then the given number is divisible by 7.",
"title": "Divisibility rules"
},
{
"paragraph_id": 70,
"text": "This rule comes from 41 ( 7 2 {\\displaystyle 7^{2}} ).",
"title": "Divisibility rules"
},
{
"paragraph_id": 71,
"text": "Examples: 12 rule → | 4 × 2 − 1 | = 7 {\\displaystyle |4\\times 2-1|=7} , which is divisible by 7. 271B rule → | 4 × B − 271 | = 235 ( 7 × 3 B ) {\\displaystyle |4\\times {\\texttt {B}}-271|=235(7\\times 3{\\texttt {B}})} , which is divisible by 7 (or apply the rule on 235).",
"title": "Divisibility rules"
},
{
"paragraph_id": 72,
"text": "OR",
"title": "Divisibility rules"
},
{
"paragraph_id": 73,
"text": "Form the alternating sum of blocks of three from right to left. If the result is divisible by 7, then the given number is divisible by 7.",
"title": "Divisibility rules"
},
{
"paragraph_id": 74,
"text": "This rule comes from 1001, since 1001 = 7 × 11 × 17 {\\displaystyle 1001=7\\times 11\\times 17} ; thus, this rule can be also tested for the divisibility by 11 and 17.",
"title": "Divisibility rules"
},
{
"paragraph_id": 75,
"text": "Example:",
"title": "Divisibility rules"
},
{
"paragraph_id": 76,
"text": "386,967,443 → 443 − 967 + 386 = − 168 {\\displaystyle 443-967+386=-168} , which is divisible by 7.",
"title": "Divisibility rules"
},
{
"paragraph_id": 77,
"text": "If the two-digit number formed by the last two digits of the given number is divisible by 8, then the given number is divisible by 8.",
"title": "Divisibility rules"
},
{
"paragraph_id": 78,
"text": "Example: 1B48, 4120",
"title": "Divisibility rules"
},
{
"paragraph_id": 79,
"text": "If the two-digit number formed by the last two digits of the given number is divisible by 9, then the given number is divisible by 9.",
"title": "Divisibility rules"
},
{
"paragraph_id": 80,
"text": "Example: 7423, 8330",
"title": "Divisibility rules"
},
{
"paragraph_id": 81,
"text": "If the number is divisible by 2 and 5, then the number is divisible by A.",
"title": "Divisibility rules"
},
{
"paragraph_id": 82,
"text": "If the sum of the digits of a number is divisible by B, then the number is divisible by B (the equivalent of casting out nines in decimal).",
"title": "Divisibility rules"
},
{
"paragraph_id": 83,
"text": "Example: 29, 61B13",
"title": "Divisibility rules"
},
{
"paragraph_id": 84,
"text": "If a number is divisible by 10, then the unit digit of that number will be 0.",
"title": "Divisibility rules"
},
{
"paragraph_id": 85,
"text": "Sum the alternate digits and subtract the sums. If the result is divisible by 11, the number is divisible by 11 (the equivalent of divisibility by eleven in decimal).",
"title": "Divisibility rules"
},
{
"paragraph_id": 86,
"text": "Example: 66, 9427",
"title": "Divisibility rules"
},
{
"paragraph_id": 87,
"text": "If the number is divisible by 2 and 7, then the number is divisible by 12.",
"title": "Divisibility rules"
},
{
"paragraph_id": 88,
"text": "If the number is divisible by 3 and 5, then the number is divisible by 13.",
"title": "Divisibility rules"
},
{
"paragraph_id": 89,
"text": "If the two-digit number formed by the last two digits of the given number is divisible by 14, then the given number is divisible by 14.",
"title": "Divisibility rules"
},
{
"paragraph_id": 90,
"text": "Example: 1468, 7394",
"title": "Divisibility rules"
},
{
"paragraph_id": 91,
"text": "Duodecimal fractions for rational numbers with 3-smooth denominators terminate:",
"title": "Fractions and irrational numbers"
},
{
"paragraph_id": 92,
"text": "while other rational numbers have recurring duodecimal fractions:",
"title": "Fractions and irrational numbers"
},
{
"paragraph_id": 93,
"text": "As explained in recurring decimals, whenever an irreducible fraction is written in radix point notation in any base, the fraction can be expressed exactly (terminates) if and only if all the prime factors of its denominator are also prime factors of the base.",
"title": "Fractions and irrational numbers"
},
{
"paragraph_id": 94,
"text": "Because 2 × 5 = 10 {\\displaystyle 2\\times 5=10} in the decimal system, fractions whose denominators are made up solely of multiples of 2 and 5 terminate: 1/8 = 1/(2×2×2), 1/20 = 1/(2×2×5), and 1/500 = 1/(2×2×5×5×5) can be expressed exactly as 0.125, 0.05, and 0.002 respectively. 1/3 and 1/7, however, recur (0.333... and 0.142857142857...).",
"title": "Fractions and irrational numbers"
},
{
"paragraph_id": 95,
"text": "Because 2 × 2 × 3 = 12 {\\displaystyle 2\\times 2\\times 3=12} in the duodecimal system, 1/8 is exact; 1/20 and 1/500 recur because they include 5 as a factor; 1/3 is exact, and 1/7 recurs, just as it does in decimal.",
"title": "Fractions and irrational numbers"
},
{
"paragraph_id": 96,
"text": "The number of denominators that give terminating fractions within a given number of digits, n, in a base b is the number of factors (divisors) of b n {\\displaystyle b^{n}} , the nth power of the base b (although this includes the divisor 1, which does not produce fractions when used as the denominator). The number of factors of b n {\\displaystyle b^{n}} is given using its prime factorization.",
"title": "Fractions and irrational numbers"
},
{
"paragraph_id": 97,
"text": "For decimal, 10 n = 2 n × 5 n {\\displaystyle 10^{n}=2^{n}\\times 5^{n}} . The number of divisors is found by adding one to each exponent of each prime and multiplying the resulting quantities together, so the number of factors of 10 n {\\displaystyle 10^{n}} is ( n + 1 ) ( n + 1 ) = ( n + 1 ) 2 {\\displaystyle (n+1)(n+1)=(n+1)^{2}} .",
"title": "Fractions and irrational numbers"
},
{
"paragraph_id": 98,
"text": "For example, the number 8 is a factor of 10 (1000), so 1 8 {\\textstyle {\\frac {1}{8}}} and other fractions with a denominator of 8 cannot require more than three fractional decimal digits to terminate. 5 8 = 0.625 10 . {\\textstyle {\\frac {5}{8}}=0.625_{10}.}",
"title": "Fractions and irrational numbers"
},
{
"paragraph_id": 99,
"text": "For duodecimal, 10 n = 2 2 n × 3 n {\\displaystyle 10^{n}=2^{2n}\\times 3^{n}} . This has ( 2 n + 1 ) ( n + 1 ) {\\displaystyle (2n+1)(n+1)} divisors. The sample denominator of 8 is a factor of a gross 12 2 = 144 {\\textstyle 12^{2}=144} in decimal), so eighths cannot need more than two duodecimal fractional places to terminate. 5 8 = 0.76 12 . {\\textstyle {\\frac {5}{8}}=0.76_{12}.}",
"title": "Fractions and irrational numbers"
},
{
"paragraph_id": 100,
"text": "Because both ten and twelve have two unique prime factors, the number of divisors of b n {\\displaystyle b^{n}} for b = 10 or 12 grows quadratically with the exponent n (in other words, of the order of n 2 {\\displaystyle n^{2}} ).",
"title": "Fractions and irrational numbers"
},
{
"paragraph_id": 101,
"text": "The Dozenal Society of America argues that factors of 3 are more commonly encountered in real-life division problems than factors of 5. Thus, in practical applications, the nuisance of repeating decimals is encountered less often when duodecimal notation is used. Advocates of duodecimal systems argue that this is particularly true of financial calculations, in which the twelve months of the year often enter into calculations.",
"title": "Fractions and irrational numbers"
},
{
"paragraph_id": 102,
"text": "However, when recurring fractions do occur in duodecimal notation, they are less likely to have a very short period than in decimal notation, because 12 (twelve) is between two prime numbers, 11 (eleven) and 13 (thirteen), whereas ten is adjacent to the composite number 9. Nonetheless, having a shorter or longer period does not help the main inconvenience that one does not get a finite representation for such fractions in the given base (so rounding, which introduces inexactitude, is necessary to handle them in calculations), and overall one is more likely to have to deal with infinite recurring digits when fractions are expressed in decimal than in duodecimal, because one out of every three consecutive numbers contains the prime factor 3 in its factorization, whereas only one out of every five contains the prime factor 5. All other prime factors, except 2, are not shared by either ten or twelve, so they do not influence the relative likeliness of encountering recurring digits (any irreducible fraction that contains any of these other factors in its denominator will recur in either base).",
"title": "Fractions and irrational numbers"
},
{
"paragraph_id": 103,
"text": "Also, the prime factor 2 appears twice in the factorization of twelve, whereas only once in the factorization of ten; which means that most fractions whose denominators are powers of two will have a shorter, more convenient terminating representation in duodecimal than in decimal:",
"title": "Fractions and irrational numbers"
},
{
"paragraph_id": 104,
"text": "The duodecimal period length of 1/n are (in decimal)",
"title": "Fractions and irrational numbers"
},
{
"paragraph_id": 105,
"text": "The duodecimal period length of 1/(nth prime) are (in decimal)",
"title": "Fractions and irrational numbers"
},
{
"paragraph_id": 106,
"text": "Smallest prime with duodecimal period n are (in decimal)",
"title": "Fractions and irrational numbers"
},
{
"paragraph_id": 107,
"text": "The representations of irrational numbers in any positional number system (including decimal and duodecimal) neither terminate nor repeat. The following table gives the first digits for some important algebraic and transcendental numbers in both decimal and duodecimal.",
"title": "Fractions and irrational numbers"
}
] | The duodecimal system is a positional notation numeral system using twelve as its base. The number twelve is instead written as "10" in duodecimal, whereas the digit string "12" means "1 dozen and 2 units". Similarly, in duodecimal, "100" means "1 gross", "1000" means "1 great gross", and "0.1" means "1 twelfth". Various symbols have been used to stand for ten and eleven in duodecimal notation; this page uses A and B, as in hexadecimal, which make a duodecimal count from zero to twelve read 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, A, B, 10. The Dozenal Societies of America and Great Britain use turned digits in their published material: 2 for ten and 3 for eleven. The number twelve, a superior highly composite number, is the smallest number with four non-trivial factors, and the smallest to include as factors all four numbers within the subitizing range, and the smallest abundant number. All multiples of reciprocals of 3-smooth numbers have a terminating representation in duodecimal. In particular, +1⁄4 (0.3), +1⁄3 (0.4), +1⁄2 (0.6), +2⁄3 (0.8), and +3⁄4 (0.9) all have a short terminating representation in duodecimal. There is also higher regularity observable in the duodecimal multiplication table. As a result, duodecimal has been described as the optimal number system. In these respects, duodecimal is considered superior to decimal and other proposed bases like octal or hexadecimal. Sexagesimal does even better in this respect, but at the cost of unwieldy multiplication tables and a much larger number of symbols to memorize. | 2001-09-06T08:39:27Z | 2023-12-08T11:26:43Z | [
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8,401 | David Hayes Agnew | David Hayes Agnew (November 24, 1818 – March 22, 1892) was an American surgeon.
Agnew was born on November 24, 1818, Nobleville, Pennsylvania (present-day Christiana). His parents were Robert Agnew and Agnes Noble. Agnew grew up as a Christian. He was surrounded by a family of doctors and had always known he was going to become a physician. As a young boy, he had a sharp sense of humor and was very intelligent.
He was educated at Jefferson College, and at Delaware College in Newark, Delaware. He graduated from the University of Pennsylvania School of Medicine on April 6, 1838. He returned to Nobleville to help his father in his clinic. He worked there for two years. His father was an asthmatic and moved to Maryland in 1840 because the climate was more suited to his condition. Agnew moved with him. On November 21, 1841, he married Margaret Irwin. In 1852, he bought and revived the Philadelphia School of Anatomy. He held responsibility for ten years until 1862. During the American Civil War he was consulting surgeon in the Mower Army Hospital, near Philadelphia, and acquired a considerable reputation for his operations in cases of gunshot wounds. On December 21, 1863, he became the Demonstrator of Anatomy and Assistant Lecturer on Clinical Surgery at The University of Pennsylvania. Later, he was requested to assist the Professor of Surgery in the Conduct of the surgical clinics. In the year 1865, he gave summer instruction courses. For the next seven years, he worked for the University as Demonstrator of Anatomy. A large portion of his success was due to his wife's energy, intelligence, and determination. She gave him an impetus to try harder and not be satisfied with his first try.
He was elected as a member of the American Philosophical Society in 1872.
On July 2, 1881, President James A. Garfield was shot by Charles J. Guiteau. He held the position of chief consulting surgeon. When a committee came to give him his money for helping, Agnew said, "Gentlemen, I present no bill for my attendance to President Garfield. I gave my services freely and gratuitously". He was never optimistic about the President's case and was not fooled by fallacious beliefs. This procedure helped create Agnew's reputation.
The Agnew Clinic is an 1889 painting by Thomas Eakins which depicts Agnew conducting a mastectomy operation before a gallery of students and doctors.
David Agnew wrote The Principles and Practice of Surgery, covers an experience of fifty active years, and its value, preserving and presenting as it does the life-work of such a recognized authority, can hardly be overrated. It was a three-volume set that he published from 1878–1883. He also helped found the Irwin & Agnew Iron Foundry in 1846.
Agnew caught a severe attack of epidemic influenza in 1890. He never fully recovered. Following this, he had an attack of broncho-vesicular catarrh. On March 9, 1892, he was put to bed for a series of medical problems. After a few days his condition began to improve, but suddenly, on March 12 it became much worse. On March 20, he fell into a comatose condition. Agnew stayed like this until he died at 3:20 p.m. on March 22, 1892. He is now buried in West Laurel Hill Cemetery.
Attribution: | [
{
"paragraph_id": 0,
"text": "David Hayes Agnew (November 24, 1818 – March 22, 1892) was an American surgeon.",
"title": ""
},
{
"paragraph_id": 1,
"text": "Agnew was born on November 24, 1818, Nobleville, Pennsylvania (present-day Christiana). His parents were Robert Agnew and Agnes Noble. Agnew grew up as a Christian. He was surrounded by a family of doctors and had always known he was going to become a physician. As a young boy, he had a sharp sense of humor and was very intelligent.",
"title": "Biography"
},
{
"paragraph_id": 2,
"text": "He was educated at Jefferson College, and at Delaware College in Newark, Delaware. He graduated from the University of Pennsylvania School of Medicine on April 6, 1838. He returned to Nobleville to help his father in his clinic. He worked there for two years. His father was an asthmatic and moved to Maryland in 1840 because the climate was more suited to his condition. Agnew moved with him. On November 21, 1841, he married Margaret Irwin. In 1852, he bought and revived the Philadelphia School of Anatomy. He held responsibility for ten years until 1862. During the American Civil War he was consulting surgeon in the Mower Army Hospital, near Philadelphia, and acquired a considerable reputation for his operations in cases of gunshot wounds. On December 21, 1863, he became the Demonstrator of Anatomy and Assistant Lecturer on Clinical Surgery at The University of Pennsylvania. Later, he was requested to assist the Professor of Surgery in the Conduct of the surgical clinics. In the year 1865, he gave summer instruction courses. For the next seven years, he worked for the University as Demonstrator of Anatomy. A large portion of his success was due to his wife's energy, intelligence, and determination. She gave him an impetus to try harder and not be satisfied with his first try.",
"title": "Biography"
},
{
"paragraph_id": 3,
"text": "He was elected as a member of the American Philosophical Society in 1872.",
"title": "Biography"
},
{
"paragraph_id": 4,
"text": "On July 2, 1881, President James A. Garfield was shot by Charles J. Guiteau. He held the position of chief consulting surgeon. When a committee came to give him his money for helping, Agnew said, \"Gentlemen, I present no bill for my attendance to President Garfield. I gave my services freely and gratuitously\". He was never optimistic about the President's case and was not fooled by fallacious beliefs. This procedure helped create Agnew's reputation.",
"title": "Garfield case"
},
{
"paragraph_id": 5,
"text": "The Agnew Clinic is an 1889 painting by Thomas Eakins which depicts Agnew conducting a mastectomy operation before a gallery of students and doctors.",
"title": "The Agnew Clinic"
},
{
"paragraph_id": 6,
"text": "David Agnew wrote The Principles and Practice of Surgery, covers an experience of fifty active years, and its value, preserving and presenting as it does the life-work of such a recognized authority, can hardly be overrated. It was a three-volume set that he published from 1878–1883. He also helped found the Irwin & Agnew Iron Foundry in 1846.",
"title": "Accomplishments"
},
{
"paragraph_id": 7,
"text": "Agnew caught a severe attack of epidemic influenza in 1890. He never fully recovered. Following this, he had an attack of broncho-vesicular catarrh. On March 9, 1892, he was put to bed for a series of medical problems. After a few days his condition began to improve, but suddenly, on March 12 it became much worse. On March 20, he fell into a comatose condition. Agnew stayed like this until he died at 3:20 p.m. on March 22, 1892. He is now buried in West Laurel Hill Cemetery.",
"title": "Death"
},
{
"paragraph_id": 8,
"text": "Attribution:",
"title": "References"
}
] | David Hayes Agnew was an American surgeon. | 2023-02-13T06:20:21Z | [
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|
8,402 | Diving (sport) | Diving is the sport of jumping or falling into water from a platform or springboard, usually while performing acrobatics. Diving is an internationally recognized sport that is part of the Olympic Games. In addition, unstructured and non-competitive diving is a recreational pastime.
Competitors possess many of the same characteristics as gymnasts and dancers, including strength, flexibility, kinaesthetic judgment and air awareness. Some professional divers were originally gymnasts or dancers as both the sports have similar characteristics to diving. Dmitri Sautin holds the record for most Olympic diving medals won, by winning eight medals in total between 1992 and 2008.
The Tomb of the Diver, dating to 470 BCE, contains a single enigmatic fresco clearly depicting a young man diving into a curling and waving stream of water.
Although diving has been a popular pastime across the world since ancient times, the first modern diving competitions were held in England in the 1880s. The exact origins of the sport are unclear, though it likely derives from the act of diving at the start of swimming races. The 1904 book Swimming by Ralph Thomas notes English reports of plunging records dating back to at least 1865. The 1877 edition to British Rural Sports by John Henry Walsh makes note of a "Mr. Young" plunging 56 feet (17 m) in 1870, and also states that 25 years prior, a swimmer named Drake could cover 53 feet (16 m).
The English Amateur Swimming Association (at the time called the Swimming Association of Great Britain) first started a "plunging championship" in 1883. The Plunging Championship was discontinued in 1937.
Diving into a body of water had also been a method used by gymnasts in Germany and Sweden since the early 19th century. The soft landing allowed for more elaborate gymnastic feats in midair as the jump could be made from a greater height. This tradition evolved into 'fancy diving', while diving as a preliminary to swimming became known as 'Plain diving'.
In England, the practice of high diving – diving from a great height – gained popularity; the first diving stages were erected at the Highgate Ponds at a height of 15 feet (4.6 m) in 1893 and the first world championship event, the National Graceful Diving Competition, was held there by the Royal Life Saving Society in 1895. The event consisted of standing and running dives from either 15 or 30 feet (4.6 or 9.1 m).
It was at this event that the Swedish tradition of fancy diving was introduced to the sport by the athletes Otto Hagborg and C F Mauritzi. They demonstrated their acrobatic techniques from the 10 m diving board at Highgate Pond and stimulated the establishment of the Amateur Diving Association in 1901, the first organization devoted to diving in the world (later amalgamated with the Amateur Swimming Association). Fancy diving was formally introduced into the championship in 1903.
Plain diving was first introduced into the Olympics at the 1904 event. The 1908 Olympics in London added 'fancy diving' and introduced elastic boards rather than fixed platforms. Women were first allowed to participate in the diving events for the 1912 Olympics in Stockholm.
In the 1928 Olympics, 'plain' and 'fancy' diving were amalgamated into one event – 'Highboard Diving'. The diving event was first held indoors in the Empire Pool for the 1934 British Empire Games and 1948 Summer Olympics in London.
Most diving competitions consist of three disciplines: 1 m and 3 m springboards, and the platform. Competitive athletes are divided by gender, and often by age group. In platform events, competitors are allowed to perform their dives on either the five, seven and a half (generally just called seven), nine, or ten meter towers. In major diving meets, including the Olympic Games and the World Championships, platform diving is from the 10 meter height.
Divers have to perform a set number of dives according to established requirements, including somersaults and twists. Divers are judged on whether and how well they completed all aspects of the dive, the conformance of their body to the requirements of the dive, and the amount of splash created by their entry to the water. A possible score out of ten is broken down into three points for the takeoff (meaning the hurdle), three for the flight (the actual dive), and three for the entry (how the diver hits the water), with one more available to give the judges flexibility.
The raw score is multiplied by a degree of difficulty factor, derived from the number and combination of movements attempted. The diver with the highest total score after a sequence of dives is declared the winner.
Synchronized diving was adopted as an Olympic sport in 2000. Two divers form a team and perform dives simultaneously. The dives are identical. It used to be possible to dive opposites, also known as a pinwheel, but this is no longer part of competitive synchronized diving. For example, one diver would perform a forward dive and the other an inward dive in the same position, or one would do a reverse and the other a back movement. In these events, the diving would be judged both on the quality of execution and the synchronicity – in timing of take-off and entry, height and forward travel.
There are rules governing the scoring of a dive. Usually a score considers three elements of the dive: the approach, the flight, and the entry. The primary factors affecting the scoring are:
Each dive is assigned a degree of difficulty (DD), which is determined from a combination of the moves undertaken, position used, and height. The DD value is multiplied by the scores given by the judges.
To reduce the subjectivity of scoring in major meets, panels of five or seven judges are assembled; major international events such as the Olympics use seven-judge panels. For a five-judge panel, the highest and lowest scores are discarded and the middle three are summed and multiplied by the DD. For seven-judge panels, as of the 2012 London Olympics, the two highest scores and two lowest are discarded, leaving three to be summed and multiplied by the DD. (Prior to the London Olympics, the highest and lowest scores were eliminated, and the remaining five scores were multiplied by 3⁄5, to allow for comparison to five-judge panels.) The canceling of scores is used to make it difficult for a single judge to manipulate scores.
There is a general misconception about scoring and judging. In serious meets, the absolute score is somewhat meaningless. It is the relative score, not the absolute score that wins meets. Accordingly, good judging implies consistent scoring across the dives. Specifically, if a judge consistently gives low scores for all divers, or consistently gives high scores for the same divers, the judging will yield fair relative results and will cause divers to place in the correct order. However, absolute scores have significance to the individual divers. Besides the obvious instances of setting records, absolute scores are also used for rankings and qualifications for higher level meets.
In synchronised diving events, there is a panel of seven, nine, or eleven judges; two or three to mark the execution of one diver, two or three to mark the execution of the other, and the remaining three or five to judge the synchronisation. The execution judges are positioned two on each side of the pool, and they score the diver which is nearer to them. The 2012 London Olympics saw the first use of eleven judges.
The score is computed similarly to the scores from other diving events, but has been modified starting with the 2012 London Olympics for the use of the larger judging panels. Each group of judges will have the highest and lowest scores dropped, leaving the middle score for each diver's execution and the three middle scores for synchronization. The total is then weighted by 3⁄5 and multiplied by the DD. The result is that the emphasis is on the synchronization of the divers.
The synchronisation scores are based on:
The judges may also disqualify the diver for certain violations during the dive, including:
To win dive meets, divers create a dive list in advance of the meet. To win the meet the diver must accumulate more points than other divers. Often, simple dives with low DDs will look good to spectators but will not win meets. The competitive diver will attempt the highest DD dives possible with which they can achieve consistent, high scores. If divers are scoring 8 or 9 on most dives, it may be a sign of their extreme skill, or it may be a sign that their dive list is not competitive, and they may lose the meet to a diver with higher DDs and lower scores.
In competition, divers must submit their lists beforehand, and once past a deadline (usually when the event is announced or shortly before it begins) they cannot change their dives. If they fail to perform the dive announced, even if they physically cannot execute the dive announced or if they perform a more difficult dive, they will receive a score of zero. Under exceptional circumstances, a redive may be granted, but these are exceedingly rare (usually for very young divers just learning how to compete, or if some event outside the diver's control has caused them to be unable to perform-such as a loud noise).
In the Olympics or other highly competitive meets, many divers will have nearly the same list of dives as their competitors. The importance for divers competing at this level is not so much the DD, but how they arrange their list. Once the more difficult rounds of dives begin it is important to lead off with a confident dive to build momentum. They also tend to put a very confident dive in front of a very difficult dive to ensure that they will have a good mentality for the difficult dive. Most divers have pre-dive and post-dive rituals that help them either maintain or regain focus. Coaches also play a role in this aspect of the sport. Many divers rely on their coaches to help keep their composure during the meet. In a large meet coaches are rarely allowed on the deck to talk to their athlete so it is common to see coaches using hand gestures or body movements to communicate.
There are some American meets which will allow changes of the position of the dive even after the dive has been announced immediately before execution, but these are an exception to the rules generally observed internationally.
Generally, NCAA rules allow for dives to be changed while the diver is on the board, but the diver must request the change directly after the dive is announced. This applies especially in cases where the wrong dive is announced. If the diver pauses during his or her hurdle to ask for a change of dive, it will be declared a balk (when the diver stops mid-hurdle) and the change of dive will not be permitted.
Under FINA law, no dive may be changed after the deadline for the dive-sheet to be submitted (generally a period ranging from one hour to 24 hours, depending on the rulings made by the event organiser).
It is the diver's responsibility to ensure that the dive-sheet is filled in correctly, and also to correct the referee or announcer before the dive if they describe it incorrectly. If a dive is performed which is as submitted but not as (incorrectly) announced, it is declared failed and scores zero according to a strict reading of the FINA law. But in practice, a re-dive would usually be granted in these circumstances.
The global governing body of diving is FINA, which also governs swimming, synchronised swimming, water polo and open water swimming. Almost invariably, at national level, diving shares a governing body with the other aquatic sports.
This is frequently a source of political friction as the committees are naturally dominated by swimming officials who do not necessarily share or understand the concerns of the diving community. Divers often feel, for example, that they do not get adequate support over issues like the provision of facilities. Other areas of concern are the selection of personnel for the specialised Diving committees and for coaching and officiating at events, and the team selection for international competitions.
There are sometimes attempts to separate the governing body as a means to resolve these frustrations, but they are rarely successful. For example, in the UK the Great Britain Diving Federation was formed in 1992 with the intention of taking over the governance of Diving from the ASA (Amateur Swimming Association). Although it initially received widespread support from the diving community, the FINA requirement that international competitors had to be registered with their National Governing Body was a major factor in the abandonment of this ambition a few years later.
Since FINA refused to rescind recognition of the ASA as the British governing body for all aquatic sports including diving, this meant that the elite divers had to belong to ASA-affiliated clubs to be eligible for selection to international competition.
In the United States scholastic diving is almost always part of the school's swim team. Diving is a separate sport in Olympic and Club Diving. The NCAA will separate diving from swimming in special diving competitions after the swim season is completed.
Despite the apparent risk, the statistical incidence of injury in supervised training and competition is extremely low.
The majority of accidents that are classified as 'diving-related' are incidents caused by individuals jumping from structures such as bridges or piers into water of inadequate depth. Many accidents also occur when divers do not account for rocks and logs in the water. Because of this many beaches and pools prohibit diving in shallow waters or when a lifeguard is not on duty.
After an incident in Washington in 1993, most US and other pool builders are reluctant to equip a residential swimming pool with a diving springboard so home diving pools are much less common these days. In the incident, 14-year-old Shawn Meneely made a "suicide dive" (holding his hands at his sides, so that his head hit the bottom first) in a private swimming pool and became a tetraplegic. The lawyers for the family, Jan Eric Peterson and Fred Zeder, successfully sued the diving board manufacturer, the pool builder, and the National Spa and Pool Institute over the inappropriate depth of the pool. The NSPI had specified a minimum depth of 7 ft 6 in (2.29 m) which proved to be insufficient in the above case. The pool into which Meneely dived was not constructed to the published standards. The standards had changed after the diving board was installed on the non-compliant pool by the homeowner. But the courts held that the pool "was close enough" to the standards to hold NSPI liable. The multimillion-dollar lawsuit was eventually resolved in 2001 for US$6.6 million ($8 million after interest was added) in favor of the plaintiff. The NSPI was held to be liable, and was financially strained by the case. It filed twice for Chapter 11 bankruptcy protection and was successfully reorganized into a new swimming pool industry association.
In competitive diving, FINA takes regulatory steps to ensure that athletes are protected from the inherent dangers of the sport. For example, they impose restrictions according to age on the heights of platforms which divers may compete on.
Group D divers have only recently been allowed to compete on the tower. In the past, the age group could compete only springboard, to discourage children from taking on the greater risks of tower diving. Group D tower was introduced to counteract the phenomenon of coaches pushing young divers to compete in higher age categories, thus putting them at even greater risk.
However, some divers may safely dive in higher age categories to dive on higher platforms. Usually this occurs when advanced Group C divers wish to compete on the 10 m.
Points on pool depths in connection with safety:
There are six "groups" into which dives are classified: Forward, Back, Inward, Reverse, Twist, and Armstand. The armstand group applies only to Platform competitions, whereas the other five groups apply to both Springboard and Platform.
During the flight of the dive, one of four positions is assumed:
These positions are referred to by the letters A, B, C and D respectively.
Additionally, some dives can be started in a flying position. The body is kept straight with the arms extended to the side, and the regular dive position is assumed at about half the dive.
Difficulty is rated according to the Degree of Difficulty of the dives. Some divers may find pike easier in a flip than tuck, and most find straight the easiest in a front/back dive, although it is still rated the most difficult because of the risk of overrotation.
An armstand dive may have a higher degree of difficulty outdoors compared to indoors as wind can destabilize the equilibrium of the diver.
In competition, the dives are referred to by a schematic system of three- or four-digit numbers. The letter to indicate the position is appended to the end of the number.
The first digit of the number indicates the dive group as defined above.
For groups 1 to 4, the number consists of three digits and a letter of the alphabet. The third digit represents the number of half-somersaults. The second digit is either 0 or 1, with 0 representing a normal somersault, and 1 signifying a "flying" variation of the basic movement (i.e. the first half somersault is performed in the straight position, and then the pike or tuck shape is assumed). No flying dive has been competed at a high level competition for many years.
For example:
For Group 5, the dive number has 4 digits. The first digit indicates that it is a twisting dive. The second digit indicates the group (1–4) of the underlying movement; the third digit indicates the number of half-somersaults, and the fourth indicates the number of half-twists.
For example:
For Group 6 – Armstand – the dive number has either three or four digits: Three digits for dives without twist and four for dives with twists.
In non-twisting armstand dives, the second digit indicates the direction of rotation (0 = no rotation, 1 = forward, 2 = backward, 3 = reverse, 4 = inward) and the third digit indicates the number of half-somersaults. Inward-rotating armstand dives have never been performed, and are generally regarded as physically impossible.
For example:
For twisting Armstand dives, the dive number again has 4 digits, but rather than beginning with the number 5, the number 6 remains as the first digit, indicating that the "twister" will be performed from an Armstand. The second digit indicates the direction of rotation – as above, the third is the number of half-somersaults, and the fourth is the number of half-twists:
e.g. 6243D – armstand back double-somersault with one and a half twists in the free position
All of these dives come with DD (degree of difficulty) this is an indication of how difficult/complex a dive is. The score that the dive receives is multiplied by the DD (also known as tariff) to give the dive a final score. Before a diver competes they must decide on a "list" this is a number of optional dives and compulsory dives. The optionals come with a DD limit. this means that a diver must select X number of dives and the combined DD limit must be no more than the limit set by the competition/organisation etc.
Until the mid-1990s the tariff was decided by the FINA diving committee, and divers could only select from the range of dives in the published tariff table. Since then, the tariff is calculated by a formula based on various factors such as the number of twist and somersaults, the height, the group etc., and divers are free to submit new combinations. This change was implemented because new dives were being invented too frequently for an annual meeting to accommodate the progress of the sport.
At the moment of take-off, two critical aspects of the dive are determined, and cannot subsequently be altered during the execution. One is the trajectory of the dive, and the other is the magnitude of the angular momentum.
The speed of rotation – and therefore the total amount of rotation – may be varied from moment to moment by changing the shape of the body, in accordance with the law of conservation of angular momentum.
The center of mass of the diver follows a parabolic path in free-fall under the influence of gravity (ignoring the effects of air resistance, which are negligible at the speeds involved).
Since the parabola is symmetrical, the travel away from the board as the diver passes it is twice the amount of the forward travel at the peak of the flight. Excessive forward distance to the entry point is penalized when scoring a dive, but obviously an adequate clearance from the diving board is essential on safety grounds.
The greatest possible height that can be achieved is desirable for several reasons:
The magnitude of angular momentum remains constant throughout the dive, but since
and the moment of inertia is larger when the body has an increased radius, the speed of rotation may be increased by moving the body into a compact shape, and reduced by opening out into a straight position.
Since the tucked shape is the most compact, it gives the most control over rotational speed, and dives in this position are easier to perform. Dives in the straight position are hardest, since there is almost no scope for altering the speed, so the angular momentum must be created at take-off with a very high degree of accuracy. (A small amount of control is available by moving the position of the arms and by a slight hollowing of the back).
The opening of the body for the entry does not stop the rotation, but merely slows it down. The vertical entry achieved by expert divers is largely an illusion created by starting the entry slightly short of vertical, so that the legs are vertical as they disappear beneath the surface. A small amount of additional tuning is available by 'entry save' techniques, whereby underwater movements of the upper body and arms against the viscosity of the water affect the position of the legs.
Dives with multiple twists and somersaults are some of the most spectacular movements, as well as the most challenging to perform.
The rules state that twisting "must not be generated manifestly on take-off". Consequently, divers must use some of the somersaulting angular momentum to generate twisting movements. The physics of twisting can be explained by looking at the components of the angular momentum vector.
As the diver leaves the board, the total angular momentum vector is horizontal, pointing directly to the left for a forward dive for example. For twisting rotation to exist, it is necessary to tilt the body sideways after takeoff, so that there is now a small component of this horizontal angular momentum vector along the body's long axis. The tilt can be seen in the photo.
The tilting is done by the arms, which are outstretched to the sides just before the twist. When one arm is moved up and the other is moved down (like turning a big steering wheel), the body reacts by tilting to the side, which then begins the twisting rotation. At the completion of the required number of twist rotations, the arm motion is reversed (the steering wheel is turned back), which removes the body's tilt and stops the twisting rotation.
An alternative explanation is that the moving arms have precession torque on them which set the body into twisting rotation. Moving the arms back produces opposite torque which stops the twisting rotation.
The rules state that the body should be vertical, or nearly so, for entry. Strictly speaking, it is physically impossible to achieve a literally vertical position throughout the entry as there will inevitably still be some rotational momentum while the body is entering the water. Divers therefore attempt to create the illusion of being vertical, especially when performing rapidly rotating multiple somersault movements. For back entries, one technique is to allow the upper body to enter slightly short of vertical so that the continuing rotation leaves the final impression of the legs entering vertically. This is called "Pike save". Another is to use "knee save" movements of scooping the upper body underwater in the direction of rotation so as to counteract the rotation of the legs.
The arms must be beside the body for feet-first dives, which are typically competed only on the 1m springboard and only at fairly low levels of 3m springboard, and extended forwards in line for "head-first" dives, which are much more common competitively. It used to be common for the hands to be interlocked with the fingers extended towards the water, but a different technique has become favoured during the last few decades. Now the usual practice is for one hand to grasp the other with palms down to strike the water with a flat surface. This creates a vacuum between the hands, arms and head which, with a vertical entry, will pull down and under any splash until deep enough to have minimal effect on the surface of the water (the so-called "rip entry").
Once a diver is completely under the water they may choose to roll or scoop in the same direction their dive was rotating to pull their legs into a more vertical position. Apart from aesthetic considerations, it is important from a safety point of view that divers reinforce the habit of rolling in the direction of rotation, especially for forward and inward entries. Back injuries such as hyperextension are caused by attempting to re-surface in the opposite direction. Diving from the higher levels increases the danger and likelihood of such injuries.
In Canada, elite competitive diving is regulated by DPC (Diving Plongeon Canada), although the individual provinces also have organizational bodies. The main competitive season runs from February to July, although some competitions may be held in January or December, and many divers (particularly international level athletes) will train and compete year round.
Most provincial level competitions consist of events for six age groups (Groups A, B, C, D, E, and Open) for both genders on each of the three board levels. These age groups roughly correspond to those standardized by FINA, with the addition of a youngest age group for divers 9 and younger, Group E, which does not compete nationally and does not have a tower event (although divers of this age may choose to compete in Group D). The age group Open is so called because divers of any age, including those over 18, may compete in these events, so long as their dives meet a minimum standard of difficulty.
Although Canada is internationally a fairly strong country in diving, the vast majority of Canadian high schools and universities do not have diving teams, and many Canadian divers accept athletic scholarships from American colleges.
Adult divers who are not competitive at an elite level may compete in masters diving. Typically, masters are either adults who never practiced the sport as children or teenagers, or former elite athletes who have retired but still seek a way to be involved in the sport. Many diving clubs have masters teams in addition to their primary competitive ones, and while some masters dive only for fun and fitness, there are also masters competitions, which range from the local to world championship level.
Divers can qualify to compete at the age group national championships, or junior national championships, in their age groups as assigned by FINA up to the age of 18. This competition is held annually in July. Qualification is based on achieving minimum scores at earlier competitions in the season, although athletes who place very highly at a national championship will be automatically qualified to compete at the next. Divers must qualify at two different competitions, at least one of which must be a level 1 competition, i.e. a competition with fairly strict judging patterns. Such competitions include the Polar Bear Invitational in Winnipeg, the Sting in Victoria, and the Alberta Provincial Championships in Edmonton or Calgary. The qualifying scores are determined by DPC according to the results of the preceding year's national competition, and typically do not have much variation from year to year.
Divers older than 18, or advanced divers of younger ages, can qualify for the senior national championships, which are held twice each year, once roughly in March and once in June or July. Once again, qualification is based on achieving minimum scores at earlier competitions (in this case, within the 12 months preceding the national championships, and in an Open age group event), or high placements in previous national championships or international competitions. It is no longer the case that divers may use results from age group events to qualify for senior nationals, or results from Open events to qualify for age group nationals.
In the Republic of Ireland facilities are limited to one operational pool at the National Aquatic Centre in Dublin. Other facilities with diving boards at the University of Limerick are undergoing staff training in an effort to start diving programmes.
National championships take place late in the year, usually during November. The competition is held at the National Aquatic Centre in Dublin and consists of four events:
In the United Kingdom, diving competitions on all boards run throughout the year. National Masters' Championships are held two or three times per year.
In the United States, summer diving is usually limited to one meter diving at community or country club pools. Some pools organize to form intra-pool competitions. These competitions are usually designed to accommodate all school-age children.
In the United States scholastic diving at the high school level is usually limited to one meter diving (but some schools use three meter springboards.). Scores from those one meter dives contribute to the swim team's overall score. High school diving and swimming concludes their season with a state competition. Depending on the state and the number of athletes competing in the state, certain qualifications must be achieved to compete in the state's championship meet. There are often regional championships and district championships which are necessary to compete in before reaching the state meet to narrow the field to only the most competitive athletes. Most state championship meets consist of eleven dives. The eleven dives are usually split up between two categories: five required (voluntary) dives and six optional dives.
In the United States, pre-college divers interested in learning one and three meter or platform diving should consider a club sanctioned by either USA Diving or AAU Diving. In USA Diving, Future Champions is the entry level or novice diver category with eight levels of competition. From Future Champions, divers graduate to "Junior Olympic", or JO. JO divers compete in age groups at inter-club competitions, at invitationals, and if qualified, at regional, zone and national competitions. Divers over the age of 19 years of age cannot compete in these events as a JO diver.
USA Diving sanctions the Winter Nationals championship with one, three meter, and platform events. In the summer USA Diving sanctions the Summer Nationals including all three events with both Junior and Senior divers. USA Diving is sanctioned by the United States Olympic Committee to select team representatives for international diving competitions including the World Championships and Olympic Games.
AAU Diving sanctions one national event per year in the summer. AAU competes on the one, three, and tower to determine the All-American team.
In the United States scholastic diving at the college level requires one and three meter diving. Scores from the one and three meter competition contribute to the swim team's overall meet score. College divers interested in tower diving may compete in the NCAA separate from swim team events. NCAA Divisions II and III do not usually compete platform; if a diver wishes to compete platform in college, he or she must attend a Division I school.
Each division also has rules on the number of dives in each competition. Division II schools compete with 10 dives in competition whereas Division III schools compete with 11. Division I schools only compete with 6 dives in competition. These 6 dives consist of either 5 optionals and 1 voluntary, or 6 optionals. If the meet is a 5 optional meet, then the divers will perform 1 optional from each category (Front, Back, Inward, Reverse, and Twister) and then 1 voluntary from the category of their choice. The voluntary in this type of meet is always worth a DD (Degree of Difficulty) of 2.0 even if the real DD is worth more or less on a DD sheet. In a 6 optional meet, the divers will yet again perform one dive from each category, but this time they will perform a 6th optional from the category of their choosing, which is worth its actual DD from the DD sheet.
The highest level of collegiate competition is the NCAA Division 1 Swimming and Diving Championship. Events at the championship include 1 meter springboard, 3 meter springboard, and platform, as well as various swimming individual and relay events. The points scored by swimmers and divers are combined to determine a team swimming & diving champion. To qualify for a diving event at the NCAA championships, a competitor must first finish in the top three at one of five zone championships, which are held after the various conference championship meets. A diver who scores at least 310 points on the 3 meter springboard and 300 points on the 1 meter springboard in a 6 optional meet can participate in the particular zone championship corresponding to the geographic region in which his or her school lies.
A number of colleges and universities offer scholarships to men and women who have competitive diving skills. These scholarships are usually offered to divers with age-group or club diving experience.
The NCAA limits the number of years a college student can represent any school in competitions. The limit is four years, but could be less under certain circumstances.
Divers who continue diving past their college years can compete in Masters' Diving programs. Masters' diving programs are frequently offered by college or club programs.
Masters' Diving events are normally conducted in age-groups separated by five or ten years, and attract competitors of a wide range of ages and experience (many, indeed, are newcomers to the sport); the oldest competitor in a Masters' Diving Championship was Viola Krahn, who at the age of 101 was the first person in any sport, male or female, anywhere in the world, to compete in an age-group of 100+ years in a nationally organized competition.
Diving is also popular as a non-competitive activity. Such diving usually emphasizes the airborne experience, and the height of the dive, but does not emphasize what goes on once the diver enters the water. The ability to dive underwater can be a useful emergency skill, and is an important part of watersport and navy safety training. Entering water from a height is an enjoyable leisure activity, as is underwater swimming.
Such non-competitive diving can occur indoors and outdoors. Outdoor diving typically takes place from cliffs or other rock formations either into fresh or salt water. However, man-made diving platforms are sometimes constructed in popular swimming destinations. Outdoor diving requires knowledge of the water depth and currents as conditions can be dangerous. On occasion, the diver will inadvertently belly flop, entering the water horizontally or nearly so. The diver typically displaces a larger than usual amount of water.
A recently developing section of the sport is High Diving (e.g. see 2013 World Aquatics Championships), conducted in open air locations, usually from improvised platforms up to 27 meters (89 ft) high (as compared with 10 meters (33 ft) as used in Olympic and World Championship events). Entry to the water is invariably feet-first to avoid the risk of injury that would be involved in head-first entry from that height. The final half-somersault is almost always performed backwards, enabling the diver to spot the entry point and control their rotation.
Competitive high diving is run as the Red Bull Cliff Diving World Series. | [
{
"paragraph_id": 0,
"text": "Diving is the sport of jumping or falling into water from a platform or springboard, usually while performing acrobatics. Diving is an internationally recognized sport that is part of the Olympic Games. In addition, unstructured and non-competitive diving is a recreational pastime.",
"title": ""
},
{
"paragraph_id": 1,
"text": "Competitors possess many of the same characteristics as gymnasts and dancers, including strength, flexibility, kinaesthetic judgment and air awareness. Some professional divers were originally gymnasts or dancers as both the sports have similar characteristics to diving. Dmitri Sautin holds the record for most Olympic diving medals won, by winning eight medals in total between 1992 and 2008.",
"title": ""
},
{
"paragraph_id": 2,
"text": "The Tomb of the Diver, dating to 470 BCE, contains a single enigmatic fresco clearly depicting a young man diving into a curling and waving stream of water.",
"title": "History"
},
{
"paragraph_id": 3,
"text": "Although diving has been a popular pastime across the world since ancient times, the first modern diving competitions were held in England in the 1880s. The exact origins of the sport are unclear, though it likely derives from the act of diving at the start of swimming races. The 1904 book Swimming by Ralph Thomas notes English reports of plunging records dating back to at least 1865. The 1877 edition to British Rural Sports by John Henry Walsh makes note of a \"Mr. Young\" plunging 56 feet (17 m) in 1870, and also states that 25 years prior, a swimmer named Drake could cover 53 feet (16 m).",
"title": "History"
},
{
"paragraph_id": 4,
"text": "The English Amateur Swimming Association (at the time called the Swimming Association of Great Britain) first started a \"plunging championship\" in 1883. The Plunging Championship was discontinued in 1937.",
"title": "History"
},
{
"paragraph_id": 5,
"text": "Diving into a body of water had also been a method used by gymnasts in Germany and Sweden since the early 19th century. The soft landing allowed for more elaborate gymnastic feats in midair as the jump could be made from a greater height. This tradition evolved into 'fancy diving', while diving as a preliminary to swimming became known as 'Plain diving'.",
"title": "History"
},
{
"paragraph_id": 6,
"text": "In England, the practice of high diving – diving from a great height – gained popularity; the first diving stages were erected at the Highgate Ponds at a height of 15 feet (4.6 m) in 1893 and the first world championship event, the National Graceful Diving Competition, was held there by the Royal Life Saving Society in 1895. The event consisted of standing and running dives from either 15 or 30 feet (4.6 or 9.1 m).",
"title": "History"
},
{
"paragraph_id": 7,
"text": "It was at this event that the Swedish tradition of fancy diving was introduced to the sport by the athletes Otto Hagborg and C F Mauritzi. They demonstrated their acrobatic techniques from the 10 m diving board at Highgate Pond and stimulated the establishment of the Amateur Diving Association in 1901, the first organization devoted to diving in the world (later amalgamated with the Amateur Swimming Association). Fancy diving was formally introduced into the championship in 1903.",
"title": "History"
},
{
"paragraph_id": 8,
"text": "Plain diving was first introduced into the Olympics at the 1904 event. The 1908 Olympics in London added 'fancy diving' and introduced elastic boards rather than fixed platforms. Women were first allowed to participate in the diving events for the 1912 Olympics in Stockholm.",
"title": "History"
},
{
"paragraph_id": 9,
"text": "In the 1928 Olympics, 'plain' and 'fancy' diving were amalgamated into one event – 'Highboard Diving'. The diving event was first held indoors in the Empire Pool for the 1934 British Empire Games and 1948 Summer Olympics in London.",
"title": "History"
},
{
"paragraph_id": 10,
"text": "Most diving competitions consist of three disciplines: 1 m and 3 m springboards, and the platform. Competitive athletes are divided by gender, and often by age group. In platform events, competitors are allowed to perform their dives on either the five, seven and a half (generally just called seven), nine, or ten meter towers. In major diving meets, including the Olympic Games and the World Championships, platform diving is from the 10 meter height.",
"title": "Competitive diving"
},
{
"paragraph_id": 11,
"text": "Divers have to perform a set number of dives according to established requirements, including somersaults and twists. Divers are judged on whether and how well they completed all aspects of the dive, the conformance of their body to the requirements of the dive, and the amount of splash created by their entry to the water. A possible score out of ten is broken down into three points for the takeoff (meaning the hurdle), three for the flight (the actual dive), and three for the entry (how the diver hits the water), with one more available to give the judges flexibility.",
"title": "Competitive diving"
},
{
"paragraph_id": 12,
"text": "The raw score is multiplied by a degree of difficulty factor, derived from the number and combination of movements attempted. The diver with the highest total score after a sequence of dives is declared the winner.",
"title": "Competitive diving"
},
{
"paragraph_id": 13,
"text": "Synchronized diving was adopted as an Olympic sport in 2000. Two divers form a team and perform dives simultaneously. The dives are identical. It used to be possible to dive opposites, also known as a pinwheel, but this is no longer part of competitive synchronized diving. For example, one diver would perform a forward dive and the other an inward dive in the same position, or one would do a reverse and the other a back movement. In these events, the diving would be judged both on the quality of execution and the synchronicity – in timing of take-off and entry, height and forward travel.",
"title": "Competitive diving"
},
{
"paragraph_id": 14,
"text": "There are rules governing the scoring of a dive. Usually a score considers three elements of the dive: the approach, the flight, and the entry. The primary factors affecting the scoring are:",
"title": "Competitive diving"
},
{
"paragraph_id": 15,
"text": "Each dive is assigned a degree of difficulty (DD), which is determined from a combination of the moves undertaken, position used, and height. The DD value is multiplied by the scores given by the judges.",
"title": "Competitive diving"
},
{
"paragraph_id": 16,
"text": "To reduce the subjectivity of scoring in major meets, panels of five or seven judges are assembled; major international events such as the Olympics use seven-judge panels. For a five-judge panel, the highest and lowest scores are discarded and the middle three are summed and multiplied by the DD. For seven-judge panels, as of the 2012 London Olympics, the two highest scores and two lowest are discarded, leaving three to be summed and multiplied by the DD. (Prior to the London Olympics, the highest and lowest scores were eliminated, and the remaining five scores were multiplied by 3⁄5, to allow for comparison to five-judge panels.) The canceling of scores is used to make it difficult for a single judge to manipulate scores.",
"title": "Competitive diving"
},
{
"paragraph_id": 17,
"text": "There is a general misconception about scoring and judging. In serious meets, the absolute score is somewhat meaningless. It is the relative score, not the absolute score that wins meets. Accordingly, good judging implies consistent scoring across the dives. Specifically, if a judge consistently gives low scores for all divers, or consistently gives high scores for the same divers, the judging will yield fair relative results and will cause divers to place in the correct order. However, absolute scores have significance to the individual divers. Besides the obvious instances of setting records, absolute scores are also used for rankings and qualifications for higher level meets.",
"title": "Competitive diving"
},
{
"paragraph_id": 18,
"text": "In synchronised diving events, there is a panel of seven, nine, or eleven judges; two or three to mark the execution of one diver, two or three to mark the execution of the other, and the remaining three or five to judge the synchronisation. The execution judges are positioned two on each side of the pool, and they score the diver which is nearer to them. The 2012 London Olympics saw the first use of eleven judges.",
"title": "Competitive diving"
},
{
"paragraph_id": 19,
"text": "The score is computed similarly to the scores from other diving events, but has been modified starting with the 2012 London Olympics for the use of the larger judging panels. Each group of judges will have the highest and lowest scores dropped, leaving the middle score for each diver's execution and the three middle scores for synchronization. The total is then weighted by 3⁄5 and multiplied by the DD. The result is that the emphasis is on the synchronization of the divers.",
"title": "Competitive diving"
},
{
"paragraph_id": 20,
"text": "The synchronisation scores are based on:",
"title": "Competitive diving"
},
{
"paragraph_id": 21,
"text": "The judges may also disqualify the diver for certain violations during the dive, including:",
"title": "Competitive diving"
},
{
"paragraph_id": 22,
"text": "To win dive meets, divers create a dive list in advance of the meet. To win the meet the diver must accumulate more points than other divers. Often, simple dives with low DDs will look good to spectators but will not win meets. The competitive diver will attempt the highest DD dives possible with which they can achieve consistent, high scores. If divers are scoring 8 or 9 on most dives, it may be a sign of their extreme skill, or it may be a sign that their dive list is not competitive, and they may lose the meet to a diver with higher DDs and lower scores.",
"title": "Competitive diving"
},
{
"paragraph_id": 23,
"text": "In competition, divers must submit their lists beforehand, and once past a deadline (usually when the event is announced or shortly before it begins) they cannot change their dives. If they fail to perform the dive announced, even if they physically cannot execute the dive announced or if they perform a more difficult dive, they will receive a score of zero. Under exceptional circumstances, a redive may be granted, but these are exceedingly rare (usually for very young divers just learning how to compete, or if some event outside the diver's control has caused them to be unable to perform-such as a loud noise).",
"title": "Competitive diving"
},
{
"paragraph_id": 24,
"text": "In the Olympics or other highly competitive meets, many divers will have nearly the same list of dives as their competitors. The importance for divers competing at this level is not so much the DD, but how they arrange their list. Once the more difficult rounds of dives begin it is important to lead off with a confident dive to build momentum. They also tend to put a very confident dive in front of a very difficult dive to ensure that they will have a good mentality for the difficult dive. Most divers have pre-dive and post-dive rituals that help them either maintain or regain focus. Coaches also play a role in this aspect of the sport. Many divers rely on their coaches to help keep their composure during the meet. In a large meet coaches are rarely allowed on the deck to talk to their athlete so it is common to see coaches using hand gestures or body movements to communicate.",
"title": "Competitive diving"
},
{
"paragraph_id": 25,
"text": "There are some American meets which will allow changes of the position of the dive even after the dive has been announced immediately before execution, but these are an exception to the rules generally observed internationally.",
"title": "Competitive diving"
},
{
"paragraph_id": 26,
"text": "Generally, NCAA rules allow for dives to be changed while the diver is on the board, but the diver must request the change directly after the dive is announced. This applies especially in cases where the wrong dive is announced. If the diver pauses during his or her hurdle to ask for a change of dive, it will be declared a balk (when the diver stops mid-hurdle) and the change of dive will not be permitted.",
"title": "Competitive diving"
},
{
"paragraph_id": 27,
"text": "Under FINA law, no dive may be changed after the deadline for the dive-sheet to be submitted (generally a period ranging from one hour to 24 hours, depending on the rulings made by the event organiser).",
"title": "Competitive diving"
},
{
"paragraph_id": 28,
"text": "It is the diver's responsibility to ensure that the dive-sheet is filled in correctly, and also to correct the referee or announcer before the dive if they describe it incorrectly. If a dive is performed which is as submitted but not as (incorrectly) announced, it is declared failed and scores zero according to a strict reading of the FINA law. But in practice, a re-dive would usually be granted in these circumstances.",
"title": "Competitive diving"
},
{
"paragraph_id": 29,
"text": "The global governing body of diving is FINA, which also governs swimming, synchronised swimming, water polo and open water swimming. Almost invariably, at national level, diving shares a governing body with the other aquatic sports.",
"title": "Governance"
},
{
"paragraph_id": 30,
"text": "This is frequently a source of political friction as the committees are naturally dominated by swimming officials who do not necessarily share or understand the concerns of the diving community. Divers often feel, for example, that they do not get adequate support over issues like the provision of facilities. Other areas of concern are the selection of personnel for the specialised Diving committees and for coaching and officiating at events, and the team selection for international competitions.",
"title": "Governance"
},
{
"paragraph_id": 31,
"text": "There are sometimes attempts to separate the governing body as a means to resolve these frustrations, but they are rarely successful. For example, in the UK the Great Britain Diving Federation was formed in 1992 with the intention of taking over the governance of Diving from the ASA (Amateur Swimming Association). Although it initially received widespread support from the diving community, the FINA requirement that international competitors had to be registered with their National Governing Body was a major factor in the abandonment of this ambition a few years later.",
"title": "Governance"
},
{
"paragraph_id": 32,
"text": "Since FINA refused to rescind recognition of the ASA as the British governing body for all aquatic sports including diving, this meant that the elite divers had to belong to ASA-affiliated clubs to be eligible for selection to international competition.",
"title": "Governance"
},
{
"paragraph_id": 33,
"text": "In the United States scholastic diving is almost always part of the school's swim team. Diving is a separate sport in Olympic and Club Diving. The NCAA will separate diving from swimming in special diving competitions after the swim season is completed.",
"title": "Governance"
},
{
"paragraph_id": 34,
"text": "Despite the apparent risk, the statistical incidence of injury in supervised training and competition is extremely low.",
"title": "Safety"
},
{
"paragraph_id": 35,
"text": "The majority of accidents that are classified as 'diving-related' are incidents caused by individuals jumping from structures such as bridges or piers into water of inadequate depth. Many accidents also occur when divers do not account for rocks and logs in the water. Because of this many beaches and pools prohibit diving in shallow waters or when a lifeguard is not on duty.",
"title": "Safety"
},
{
"paragraph_id": 36,
"text": "After an incident in Washington in 1993, most US and other pool builders are reluctant to equip a residential swimming pool with a diving springboard so home diving pools are much less common these days. In the incident, 14-year-old Shawn Meneely made a \"suicide dive\" (holding his hands at his sides, so that his head hit the bottom first) in a private swimming pool and became a tetraplegic. The lawyers for the family, Jan Eric Peterson and Fred Zeder, successfully sued the diving board manufacturer, the pool builder, and the National Spa and Pool Institute over the inappropriate depth of the pool. The NSPI had specified a minimum depth of 7 ft 6 in (2.29 m) which proved to be insufficient in the above case. The pool into which Meneely dived was not constructed to the published standards. The standards had changed after the diving board was installed on the non-compliant pool by the homeowner. But the courts held that the pool \"was close enough\" to the standards to hold NSPI liable. The multimillion-dollar lawsuit was eventually resolved in 2001 for US$6.6 million ($8 million after interest was added) in favor of the plaintiff. The NSPI was held to be liable, and was financially strained by the case. It filed twice for Chapter 11 bankruptcy protection and was successfully reorganized into a new swimming pool industry association.",
"title": "Safety"
},
{
"paragraph_id": 37,
"text": "In competitive diving, FINA takes regulatory steps to ensure that athletes are protected from the inherent dangers of the sport. For example, they impose restrictions according to age on the heights of platforms which divers may compete on.",
"title": "Safety"
},
{
"paragraph_id": 38,
"text": "Group D divers have only recently been allowed to compete on the tower. In the past, the age group could compete only springboard, to discourage children from taking on the greater risks of tower diving. Group D tower was introduced to counteract the phenomenon of coaches pushing young divers to compete in higher age categories, thus putting them at even greater risk.",
"title": "Safety"
},
{
"paragraph_id": 39,
"text": "However, some divers may safely dive in higher age categories to dive on higher platforms. Usually this occurs when advanced Group C divers wish to compete on the 10 m.",
"title": "Safety"
},
{
"paragraph_id": 40,
"text": "Points on pool depths in connection with safety:",
"title": "Safety"
},
{
"paragraph_id": 41,
"text": "There are six \"groups\" into which dives are classified: Forward, Back, Inward, Reverse, Twist, and Armstand. The armstand group applies only to Platform competitions, whereas the other five groups apply to both Springboard and Platform.",
"title": "Dive groups"
},
{
"paragraph_id": 42,
"text": "",
"title": "Dive groups"
},
{
"paragraph_id": 43,
"text": "During the flight of the dive, one of four positions is assumed:",
"title": "Dive groups"
},
{
"paragraph_id": 44,
"text": "These positions are referred to by the letters A, B, C and D respectively.",
"title": "Dive groups"
},
{
"paragraph_id": 45,
"text": "Additionally, some dives can be started in a flying position. The body is kept straight with the arms extended to the side, and the regular dive position is assumed at about half the dive.",
"title": "Dive groups"
},
{
"paragraph_id": 46,
"text": "Difficulty is rated according to the Degree of Difficulty of the dives. Some divers may find pike easier in a flip than tuck, and most find straight the easiest in a front/back dive, although it is still rated the most difficult because of the risk of overrotation.",
"title": "Dive groups"
},
{
"paragraph_id": 47,
"text": "An armstand dive may have a higher degree of difficulty outdoors compared to indoors as wind can destabilize the equilibrium of the diver.",
"title": "Dive groups"
},
{
"paragraph_id": 48,
"text": "In competition, the dives are referred to by a schematic system of three- or four-digit numbers. The letter to indicate the position is appended to the end of the number.",
"title": "Dive groups"
},
{
"paragraph_id": 49,
"text": "The first digit of the number indicates the dive group as defined above.",
"title": "Dive groups"
},
{
"paragraph_id": 50,
"text": "For groups 1 to 4, the number consists of three digits and a letter of the alphabet. The third digit represents the number of half-somersaults. The second digit is either 0 or 1, with 0 representing a normal somersault, and 1 signifying a \"flying\" variation of the basic movement (i.e. the first half somersault is performed in the straight position, and then the pike or tuck shape is assumed). No flying dive has been competed at a high level competition for many years.",
"title": "Dive groups"
},
{
"paragraph_id": 51,
"text": "For example:",
"title": "Dive groups"
},
{
"paragraph_id": 52,
"text": "For Group 5, the dive number has 4 digits. The first digit indicates that it is a twisting dive. The second digit indicates the group (1–4) of the underlying movement; the third digit indicates the number of half-somersaults, and the fourth indicates the number of half-twists.",
"title": "Dive groups"
},
{
"paragraph_id": 53,
"text": "For example:",
"title": "Dive groups"
},
{
"paragraph_id": 54,
"text": "For Group 6 – Armstand – the dive number has either three or four digits: Three digits for dives without twist and four for dives with twists.",
"title": "Dive groups"
},
{
"paragraph_id": 55,
"text": "In non-twisting armstand dives, the second digit indicates the direction of rotation (0 = no rotation, 1 = forward, 2 = backward, 3 = reverse, 4 = inward) and the third digit indicates the number of half-somersaults. Inward-rotating armstand dives have never been performed, and are generally regarded as physically impossible.",
"title": "Dive groups"
},
{
"paragraph_id": 56,
"text": "For example:",
"title": "Dive groups"
},
{
"paragraph_id": 57,
"text": "For twisting Armstand dives, the dive number again has 4 digits, but rather than beginning with the number 5, the number 6 remains as the first digit, indicating that the \"twister\" will be performed from an Armstand. The second digit indicates the direction of rotation – as above, the third is the number of half-somersaults, and the fourth is the number of half-twists:",
"title": "Dive groups"
},
{
"paragraph_id": 58,
"text": "e.g. 6243D – armstand back double-somersault with one and a half twists in the free position",
"title": "Dive groups"
},
{
"paragraph_id": 59,
"text": "All of these dives come with DD (degree of difficulty) this is an indication of how difficult/complex a dive is. The score that the dive receives is multiplied by the DD (also known as tariff) to give the dive a final score. Before a diver competes they must decide on a \"list\" this is a number of optional dives and compulsory dives. The optionals come with a DD limit. this means that a diver must select X number of dives and the combined DD limit must be no more than the limit set by the competition/organisation etc.",
"title": "Dive groups"
},
{
"paragraph_id": 60,
"text": "Until the mid-1990s the tariff was decided by the FINA diving committee, and divers could only select from the range of dives in the published tariff table. Since then, the tariff is calculated by a formula based on various factors such as the number of twist and somersaults, the height, the group etc., and divers are free to submit new combinations. This change was implemented because new dives were being invented too frequently for an annual meeting to accommodate the progress of the sport.",
"title": "Dive groups"
},
{
"paragraph_id": 61,
"text": "At the moment of take-off, two critical aspects of the dive are determined, and cannot subsequently be altered during the execution. One is the trajectory of the dive, and the other is the magnitude of the angular momentum.",
"title": "Mechanics of diving"
},
{
"paragraph_id": 62,
"text": "The speed of rotation – and therefore the total amount of rotation – may be varied from moment to moment by changing the shape of the body, in accordance with the law of conservation of angular momentum.",
"title": "Mechanics of diving"
},
{
"paragraph_id": 63,
"text": "The center of mass of the diver follows a parabolic path in free-fall under the influence of gravity (ignoring the effects of air resistance, which are negligible at the speeds involved).",
"title": "Mechanics of diving"
},
{
"paragraph_id": 64,
"text": "Since the parabola is symmetrical, the travel away from the board as the diver passes it is twice the amount of the forward travel at the peak of the flight. Excessive forward distance to the entry point is penalized when scoring a dive, but obviously an adequate clearance from the diving board is essential on safety grounds.",
"title": "Mechanics of diving"
},
{
"paragraph_id": 65,
"text": "The greatest possible height that can be achieved is desirable for several reasons:",
"title": "Mechanics of diving"
},
{
"paragraph_id": 66,
"text": "The magnitude of angular momentum remains constant throughout the dive, but since",
"title": "Mechanics of diving"
},
{
"paragraph_id": 67,
"text": "and the moment of inertia is larger when the body has an increased radius, the speed of rotation may be increased by moving the body into a compact shape, and reduced by opening out into a straight position.",
"title": "Mechanics of diving"
},
{
"paragraph_id": 68,
"text": "Since the tucked shape is the most compact, it gives the most control over rotational speed, and dives in this position are easier to perform. Dives in the straight position are hardest, since there is almost no scope for altering the speed, so the angular momentum must be created at take-off with a very high degree of accuracy. (A small amount of control is available by moving the position of the arms and by a slight hollowing of the back).",
"title": "Mechanics of diving"
},
{
"paragraph_id": 69,
"text": "The opening of the body for the entry does not stop the rotation, but merely slows it down. The vertical entry achieved by expert divers is largely an illusion created by starting the entry slightly short of vertical, so that the legs are vertical as they disappear beneath the surface. A small amount of additional tuning is available by 'entry save' techniques, whereby underwater movements of the upper body and arms against the viscosity of the water affect the position of the legs.",
"title": "Mechanics of diving"
},
{
"paragraph_id": 70,
"text": "Dives with multiple twists and somersaults are some of the most spectacular movements, as well as the most challenging to perform.",
"title": "Mechanics of diving"
},
{
"paragraph_id": 71,
"text": "The rules state that twisting \"must not be generated manifestly on take-off\". Consequently, divers must use some of the somersaulting angular momentum to generate twisting movements. The physics of twisting can be explained by looking at the components of the angular momentum vector.",
"title": "Mechanics of diving"
},
{
"paragraph_id": 72,
"text": "As the diver leaves the board, the total angular momentum vector is horizontal, pointing directly to the left for a forward dive for example. For twisting rotation to exist, it is necessary to tilt the body sideways after takeoff, so that there is now a small component of this horizontal angular momentum vector along the body's long axis. The tilt can be seen in the photo.",
"title": "Mechanics of diving"
},
{
"paragraph_id": 73,
"text": "The tilting is done by the arms, which are outstretched to the sides just before the twist. When one arm is moved up and the other is moved down (like turning a big steering wheel), the body reacts by tilting to the side, which then begins the twisting rotation. At the completion of the required number of twist rotations, the arm motion is reversed (the steering wheel is turned back), which removes the body's tilt and stops the twisting rotation.",
"title": "Mechanics of diving"
},
{
"paragraph_id": 74,
"text": "An alternative explanation is that the moving arms have precession torque on them which set the body into twisting rotation. Moving the arms back produces opposite torque which stops the twisting rotation.",
"title": "Mechanics of diving"
},
{
"paragraph_id": 75,
"text": "The rules state that the body should be vertical, or nearly so, for entry. Strictly speaking, it is physically impossible to achieve a literally vertical position throughout the entry as there will inevitably still be some rotational momentum while the body is entering the water. Divers therefore attempt to create the illusion of being vertical, especially when performing rapidly rotating multiple somersault movements. For back entries, one technique is to allow the upper body to enter slightly short of vertical so that the continuing rotation leaves the final impression of the legs entering vertically. This is called \"Pike save\". Another is to use \"knee save\" movements of scooping the upper body underwater in the direction of rotation so as to counteract the rotation of the legs.",
"title": "Mechanics of diving"
},
{
"paragraph_id": 76,
"text": "The arms must be beside the body for feet-first dives, which are typically competed only on the 1m springboard and only at fairly low levels of 3m springboard, and extended forwards in line for \"head-first\" dives, which are much more common competitively. It used to be common for the hands to be interlocked with the fingers extended towards the water, but a different technique has become favoured during the last few decades. Now the usual practice is for one hand to grasp the other with palms down to strike the water with a flat surface. This creates a vacuum between the hands, arms and head which, with a vertical entry, will pull down and under any splash until deep enough to have minimal effect on the surface of the water (the so-called \"rip entry\").",
"title": "Mechanics of diving"
},
{
"paragraph_id": 77,
"text": "Once a diver is completely under the water they may choose to roll or scoop in the same direction their dive was rotating to pull their legs into a more vertical position. Apart from aesthetic considerations, it is important from a safety point of view that divers reinforce the habit of rolling in the direction of rotation, especially for forward and inward entries. Back injuries such as hyperextension are caused by attempting to re-surface in the opposite direction. Diving from the higher levels increases the danger and likelihood of such injuries.",
"title": "Mechanics of diving"
},
{
"paragraph_id": 78,
"text": "In Canada, elite competitive diving is regulated by DPC (Diving Plongeon Canada), although the individual provinces also have organizational bodies. The main competitive season runs from February to July, although some competitions may be held in January or December, and many divers (particularly international level athletes) will train and compete year round.",
"title": "By country"
},
{
"paragraph_id": 79,
"text": "Most provincial level competitions consist of events for six age groups (Groups A, B, C, D, E, and Open) for both genders on each of the three board levels. These age groups roughly correspond to those standardized by FINA, with the addition of a youngest age group for divers 9 and younger, Group E, which does not compete nationally and does not have a tower event (although divers of this age may choose to compete in Group D). The age group Open is so called because divers of any age, including those over 18, may compete in these events, so long as their dives meet a minimum standard of difficulty.",
"title": "By country"
},
{
"paragraph_id": 80,
"text": "Although Canada is internationally a fairly strong country in diving, the vast majority of Canadian high schools and universities do not have diving teams, and many Canadian divers accept athletic scholarships from American colleges.",
"title": "By country"
},
{
"paragraph_id": 81,
"text": "Adult divers who are not competitive at an elite level may compete in masters diving. Typically, masters are either adults who never practiced the sport as children or teenagers, or former elite athletes who have retired but still seek a way to be involved in the sport. Many diving clubs have masters teams in addition to their primary competitive ones, and while some masters dive only for fun and fitness, there are also masters competitions, which range from the local to world championship level.",
"title": "By country"
},
{
"paragraph_id": 82,
"text": "Divers can qualify to compete at the age group national championships, or junior national championships, in their age groups as assigned by FINA up to the age of 18. This competition is held annually in July. Qualification is based on achieving minimum scores at earlier competitions in the season, although athletes who place very highly at a national championship will be automatically qualified to compete at the next. Divers must qualify at two different competitions, at least one of which must be a level 1 competition, i.e. a competition with fairly strict judging patterns. Such competitions include the Polar Bear Invitational in Winnipeg, the Sting in Victoria, and the Alberta Provincial Championships in Edmonton or Calgary. The qualifying scores are determined by DPC according to the results of the preceding year's national competition, and typically do not have much variation from year to year.",
"title": "By country"
},
{
"paragraph_id": 83,
"text": "Divers older than 18, or advanced divers of younger ages, can qualify for the senior national championships, which are held twice each year, once roughly in March and once in June or July. Once again, qualification is based on achieving minimum scores at earlier competitions (in this case, within the 12 months preceding the national championships, and in an Open age group event), or high placements in previous national championships or international competitions. It is no longer the case that divers may use results from age group events to qualify for senior nationals, or results from Open events to qualify for age group nationals.",
"title": "By country"
},
{
"paragraph_id": 84,
"text": "In the Republic of Ireland facilities are limited to one operational pool at the National Aquatic Centre in Dublin. Other facilities with diving boards at the University of Limerick are undergoing staff training in an effort to start diving programmes.",
"title": "By country"
},
{
"paragraph_id": 85,
"text": "National championships take place late in the year, usually during November. The competition is held at the National Aquatic Centre in Dublin and consists of four events:",
"title": "By country"
},
{
"paragraph_id": 86,
"text": "In the United Kingdom, diving competitions on all boards run throughout the year. National Masters' Championships are held two or three times per year.",
"title": "By country"
},
{
"paragraph_id": 87,
"text": "In the United States, summer diving is usually limited to one meter diving at community or country club pools. Some pools organize to form intra-pool competitions. These competitions are usually designed to accommodate all school-age children.",
"title": "By country"
},
{
"paragraph_id": 88,
"text": "In the United States scholastic diving at the high school level is usually limited to one meter diving (but some schools use three meter springboards.). Scores from those one meter dives contribute to the swim team's overall score. High school diving and swimming concludes their season with a state competition. Depending on the state and the number of athletes competing in the state, certain qualifications must be achieved to compete in the state's championship meet. There are often regional championships and district championships which are necessary to compete in before reaching the state meet to narrow the field to only the most competitive athletes. Most state championship meets consist of eleven dives. The eleven dives are usually split up between two categories: five required (voluntary) dives and six optional dives.",
"title": "By country"
},
{
"paragraph_id": 89,
"text": "In the United States, pre-college divers interested in learning one and three meter or platform diving should consider a club sanctioned by either USA Diving or AAU Diving. In USA Diving, Future Champions is the entry level or novice diver category with eight levels of competition. From Future Champions, divers graduate to \"Junior Olympic\", or JO. JO divers compete in age groups at inter-club competitions, at invitationals, and if qualified, at regional, zone and national competitions. Divers over the age of 19 years of age cannot compete in these events as a JO diver.",
"title": "By country"
},
{
"paragraph_id": 90,
"text": "USA Diving sanctions the Winter Nationals championship with one, three meter, and platform events. In the summer USA Diving sanctions the Summer Nationals including all three events with both Junior and Senior divers. USA Diving is sanctioned by the United States Olympic Committee to select team representatives for international diving competitions including the World Championships and Olympic Games.",
"title": "By country"
},
{
"paragraph_id": 91,
"text": "AAU Diving sanctions one national event per year in the summer. AAU competes on the one, three, and tower to determine the All-American team.",
"title": "By country"
},
{
"paragraph_id": 92,
"text": "In the United States scholastic diving at the college level requires one and three meter diving. Scores from the one and three meter competition contribute to the swim team's overall meet score. College divers interested in tower diving may compete in the NCAA separate from swim team events. NCAA Divisions II and III do not usually compete platform; if a diver wishes to compete platform in college, he or she must attend a Division I school.",
"title": "By country"
},
{
"paragraph_id": 93,
"text": "Each division also has rules on the number of dives in each competition. Division II schools compete with 10 dives in competition whereas Division III schools compete with 11. Division I schools only compete with 6 dives in competition. These 6 dives consist of either 5 optionals and 1 voluntary, or 6 optionals. If the meet is a 5 optional meet, then the divers will perform 1 optional from each category (Front, Back, Inward, Reverse, and Twister) and then 1 voluntary from the category of their choice. The voluntary in this type of meet is always worth a DD (Degree of Difficulty) of 2.0 even if the real DD is worth more or less on a DD sheet. In a 6 optional meet, the divers will yet again perform one dive from each category, but this time they will perform a 6th optional from the category of their choosing, which is worth its actual DD from the DD sheet.",
"title": "By country"
},
{
"paragraph_id": 94,
"text": "The highest level of collegiate competition is the NCAA Division 1 Swimming and Diving Championship. Events at the championship include 1 meter springboard, 3 meter springboard, and platform, as well as various swimming individual and relay events. The points scored by swimmers and divers are combined to determine a team swimming & diving champion. To qualify for a diving event at the NCAA championships, a competitor must first finish in the top three at one of five zone championships, which are held after the various conference championship meets. A diver who scores at least 310 points on the 3 meter springboard and 300 points on the 1 meter springboard in a 6 optional meet can participate in the particular zone championship corresponding to the geographic region in which his or her school lies.",
"title": "By country"
},
{
"paragraph_id": 95,
"text": "A number of colleges and universities offer scholarships to men and women who have competitive diving skills. These scholarships are usually offered to divers with age-group or club diving experience.",
"title": "By country"
},
{
"paragraph_id": 96,
"text": "The NCAA limits the number of years a college student can represent any school in competitions. The limit is four years, but could be less under certain circumstances.",
"title": "By country"
},
{
"paragraph_id": 97,
"text": "Divers who continue diving past their college years can compete in Masters' Diving programs. Masters' diving programs are frequently offered by college or club programs.",
"title": "By country"
},
{
"paragraph_id": 98,
"text": "Masters' Diving events are normally conducted in age-groups separated by five or ten years, and attract competitors of a wide range of ages and experience (many, indeed, are newcomers to the sport); the oldest competitor in a Masters' Diving Championship was Viola Krahn, who at the age of 101 was the first person in any sport, male or female, anywhere in the world, to compete in an age-group of 100+ years in a nationally organized competition.",
"title": "By country"
},
{
"paragraph_id": 99,
"text": "Diving is also popular as a non-competitive activity. Such diving usually emphasizes the airborne experience, and the height of the dive, but does not emphasize what goes on once the diver enters the water. The ability to dive underwater can be a useful emergency skill, and is an important part of watersport and navy safety training. Entering water from a height is an enjoyable leisure activity, as is underwater swimming.",
"title": "Non-competitive diving"
},
{
"paragraph_id": 100,
"text": "Such non-competitive diving can occur indoors and outdoors. Outdoor diving typically takes place from cliffs or other rock formations either into fresh or salt water. However, man-made diving platforms are sometimes constructed in popular swimming destinations. Outdoor diving requires knowledge of the water depth and currents as conditions can be dangerous. On occasion, the diver will inadvertently belly flop, entering the water horizontally or nearly so. The diver typically displaces a larger than usual amount of water.",
"title": "Non-competitive diving"
},
{
"paragraph_id": 101,
"text": "A recently developing section of the sport is High Diving (e.g. see 2013 World Aquatics Championships), conducted in open air locations, usually from improvised platforms up to 27 meters (89 ft) high (as compared with 10 meters (33 ft) as used in Olympic and World Championship events). Entry to the water is invariably feet-first to avoid the risk of injury that would be involved in head-first entry from that height. The final half-somersault is almost always performed backwards, enabling the diver to spot the entry point and control their rotation.",
"title": "High diving"
},
{
"paragraph_id": 102,
"text": "Competitive high diving is run as the Red Bull Cliff Diving World Series.",
"title": "High diving"
}
] | Diving is the sport of jumping or falling into water from a platform or springboard, usually while performing acrobatics. Diving is an internationally recognized sport that is part of the Olympic Games. In addition, unstructured and non-competitive diving is a recreational pastime. Competitors possess many of the same characteristics as gymnasts and dancers, including strength, flexibility, kinaesthetic judgment and air awareness. Some professional divers were originally gymnasts or dancers as both the sports have similar characteristics to diving. Dmitri Sautin holds the record for most Olympic diving medals won, by winning eight medals in total between 1992 and 2008. | 2001-09-06T14:28:18Z | 2023-09-17T21:09:01Z | [
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] | https://en.wikipedia.org/wiki/Diving_(sport) |
8,406 | Dative case | In grammar, the dative case (abbreviated dat, or sometimes d when it is a core argument) is a grammatical case used in some languages to indicate the recipient or beneficiary of an action, as in "Maria Jacobo potum dedit", Latin for "Maria gave Jacob a drink". In this example, the dative marks what would be considered the indirect object of a verb in English.
Sometimes the dative has functions unrelated to giving. In Scottish Gaelic and Irish, the term dative case is used in traditional grammars to refer to the prepositional case-marking of nouns following simple prepositions and the definite article. In Georgian and Hindustani (Hindi-Urdu), the dative case can also mark the subject of a sentence. This is called the dative construction. In Hindi, the dative construction is not limited to only certain verbs or tenses and it can be used with any verb in any tense or mood.
The dative was common among early Indo-European languages and has survived to the present in the Balto-Slavic branch, the Germanic branch, Albanian and others. It also exists in similar forms in several non-Indo-European languages, such as the Uralic family of languages. In some languages, the dative case has assimilated the functions of other, now extinct cases. In Ancient Greek, the dative has the functions of the Proto-Indo-European locative and instrumental as well as those of the original dative.
Under the influence of English, which uses the preposition "to" for (among other uses) both indirect objects (give to) and directions of movement (go to), the term "dative" has sometimes been used to describe cases that in other languages would more appropriately be called lative.
"Dative" comes from Latin cāsus datīvus ("case for giving"), a translation of Greek δοτικὴ πτῶσις, dotikē ptôsis ("inflection for giving"). Dionysius Thrax in his Art of Grammar also refers to it as epistaltikḗ "for sending (a letter)", from the verb epistéllō "send to", a word from the same root as epistle.
The Old English language had a dative case; however, the English case system gradually fell into disuse during the Middle English period, when the accusative and dative of pronouns merged into a single oblique case that was also used with all prepositions. This conflation of case in Middle and Modern English has led most modern grammarians to discard the "accusative" and "dative" labels as obsolete in reference to English, often using the term "objective" for oblique.
The dative case is rare in modern English usage, but it can be argued that it survives in a few set expressions. One example is the word "methinks", with the meaning "it seems to me". It survives in this fixed form from Old English (having undergone, however, phonetic changes with the rest of the language), in which it was constructed as "[it]" + "me" (the dative case of the personal pronoun) + "thinks" (i.e., "seems", < Old English þyncan, "to seem", a verb closely related to the verb þencan, "to think", but distinct from it in Old English; later it merged with "think" and lost this meaning).
The modern objective case pronoun whom is derived from the dative case in Old English, specifically the Old English dative pronoun "hwām" (as opposed to the modern subjective "who", which descends from Old English "hwā") – though "whom" also absorbed the functions of the Old English accusative pronoun "hwone". It is also cognate to the word "wem" (the dative form of "wer") in German. The OED defines all classical uses of the word "whom" in situations where the indirect object is not known – in effect, indicating the anonymity of the indirect object.
Likewise, some of the object forms of personal pronouns are remnants of Old English datives. For example, "him" goes back to the Old English dative him (accusative was hine), and "her" goes back to the dative hire (accusative was hīe). These pronouns are not pure datives in modern English; they are also used for functions previously indicated by the accusative.
The indirect object of the verb may be placed between the verb and the direct object of the verb: "he gave me a book" or "he wrote me a poem."
The indirect object may also be expressed using a prepositional phrase using "to": "he gave a book to me.
In general, the dative (German: Dativ) is used to mark the indirect object of a German sentence. For example:
In English, the first sentence can be rendered as "I sent the book to the man" and as "I sent the man the book", where the indirect object is identified in English by standing in front of the direct object. The normal word order in German is to put the dative in front of the accusative (as in the example above). However, since the German dative is marked in form, it can also be put after the accusative: Ich schickte das Buch dem Mann(e). The (e) after Mann and Kind signifies a now largely archaic -e ending for certain nouns in the dative. It survives today almost exclusively in set phrases such as zu Hause (at home, lit. to house), im Zuge (in the course of), and am Tage (during the day, lit. at the day), as well as in occasional usage in formal prose, poetry, and song lyrics.
Some masculine nouns (and one neuter noun, Herz [heart]), referred to as weak nouns or n-nouns, take an -n or -en in the dative singular and plural. Many are masculine nouns ending in -e in the nominative (such as Name [name], Beamte [officer], and Junge [boy]), although not all such nouns follow this rule. Many also, whether or not they fall into the former category, refer to people, animals, professions, or titles; exceptions to this include the aforementioned Herz and Name, as well as Buchstabe (letter), Friede (peace), Obelisk (obelisk), Planet (planet), and others.
Certain German prepositions require the dative: aus (from), außer (out of), bei (at, near), entgegen (against), gegenüber (opposite), mit (with), nach (after, to), seit (since), von (from), and zu (at, in, to). Some other prepositions (an [at], auf [on], entlang [along], hinter [behind], in [in, into], neben (beside, next to), über [over, across], unter [under, below], vor [in front of], and zwischen [among, between]) may be used with dative (indicating current location), or accusative (indicating direction toward something). Das Buch liegt auf dem Tisch(e) (dative: The book is lying on the table), but Ich lege das Buch auf den Tisch (accusative: I put the book onto the table).
In addition the four prepositions [an]statt (in place of), trotz (in spite of), während (during), and wegen (because of) which require the genitive in modern formal language, are most commonly used with the dative in colloquial German. For example, "because of the weather" is expressed as wegen dem Wetter instead of the formally correct wegen des Wetters. Other prepositions requiring the genitive in formal language, are combined with von ("of") in colloquial style, e.g. außerhalb vom Garten instead of außerhalb des Gartens ("outside the garden").
The concept of an indirect object may be rendered by a prepositional phrase. In this case, the noun's or pronoun's case is determined by the preposition, not by its function in the sentence. Consider this sentence:
Here, the subject, Ich, is in the nominative case, the direct object, das Buch, is in the accusative case, and zum Verleger is in the dative case, since zu always requires the dative (zum is a contraction of zu + dem). However:
In this sentence, Freund is the indirect object, but, because it follows an (direction), the accusative is required, not the dative.
All of the articles change in the dative case.
Some German verbs require the dative for their direct objects. Common examples are antworten (to answer), danken (to thank), gefallen (to please), folgen (to follow), glauben (to believe), helfen (to help), and raten (to advise). In each case, the direct object of the verb is rendered in the dative. For example:
These verbs cannot be used in normal passive constructions, because German allows these only for verbs with accusative objects. It is therefore ungrammatical to say: *Ich werde geholfen. "I am helped." Instead a special construction called "impersonal passive" must be used: Mir wird geholfen, literally: "To me is helped." A colloquial (non-standard) way to form the passive voice for dative verbs is the following: Ich kriege geholfen, or: Ich bekomme geholfen, literally: "I get helped". The use of the verb "to get" here reminds us that the dative case has something to do with giving and receiving. In German, help is not something you perform on somebody, but rather something you offer them.
The dative case is also used with reflexive (sich) verbs when specifying what part of the self the verb is being done to:
Cf. the respective accord in French: "Les enfants se sont lavés" (the children have washed themselves) vs. "Les enfants se sont lavé" [uninflected] "les mains" (... their hands).
German can use two datives to make sentences like: Sei mir meinem Sohn(e) gnädig! "For my sake, have mercy on my son!" Literally: "Be for me to my son merciful." The first dative mir ("for me") expresses the speaker's commiseration (much like the dativus ethicus in Latin, see below). The second dative meinem Sohn(e) ("to my son") names the actual object of the plea. Mercy is to be given to the son for or on behalf of his mother/father.
Adjective endings also change in the dative case. There are three inflection possibilities depending on what precedes the adjective. They most commonly use weak inflection when preceded by a definite article (the), mixed inflection after an indefinite article (a/an), and strong inflection when a quantity is indicated (many green apples).
There are several uses for the dative case (Dativus):
In addition to its main function as the dativus, the dative case has other functions in Classical Greek: (The chart below uses the Latin names for the types of dative; the Greek name for the dative is δοτική πτῶσις, like its Latin equivalent, derived from the verb "to give"; in Ancient Greek, δίδωμι.)
The articles in the Greek dative are
The dative case, strictly speaking, no longer exists in Modern Greek, except in fossilized expressions like δόξα τω Θεώ (from the ecclesiastical τῷ Θεῷ δόξα, "Glory to God") or εν τάξει (ἐν τάξει, lit. "in order", i.e. "all right" or "OK"). Otherwise, most of the functions of the dative are expressed by the genitive or by prepositional phrases.
In Russian, the dative case is used for indicating the indirect object of an action (that to which something is given, thrown, read, etc.). In the instance where a person is the goal of motion, dative is used instead of accusative to indicate motion toward. This is usually achieved with the preposition κ + destination in dative case; К врачу, meaning "to the doctor."
Dative is also the necessary case taken by certain prepositions when expressing certain ideas. For instance, when the preposition по is used to mean "along", its object is always in dative case, as in По бокам, meaning "along the sides."
Other Slavic languages apply the dative case (and the other cases) more or less the same way as does Russian; some languages may use the dative in other ways. The following examples are from Polish:
Some other kinds of dative use as found in the Serbo-Croatian language are: Dativus finalis (Titaniku u pomoć "to Titanic's rescue"), Dativus commodi/incommodi (Operi svojoj majci suđe "Wash the dishes for your mother"), Dativus possessivus (Ovcama je dlaka gusta "Sheep's hair is thick"), Dativus ethicus (Šta/što mi radi Boni? "What is Boni doing? (I am especially interested in what it is)") and Dativus auctoris (Izgleda mi okej "It seems okay to me").
Unusual in other Indo-European branches but common among Slavic languages, endings of nouns and adjectives are different based on grammatical function. Other factors are gender and number. In some cases, the ending may not be obvious, even when those three factors (function, gender, number) are considered. For example, in Polish, 'syn' ("son") and 'ojciec' ("father") are both masculine singular nouns, yet appear as syn → synowi and ojciec → ojcu in the dative.
Both Lithuanian and Latvian have a distinct dative case in the system of nominal declensions.
Lithuanian nouns preserve Indo-European inflections in the dative case fairly well: (o-stems) vaikas -> sg. vaikui, pl. vaikams; (ā-stems) ranka -> sg. rankai, pl. rankoms; (i-stems) viltis -> sg. vilčiai, pl. viltims; (u-stems) sūnus -> sg. sūnui, pl. sūnums; (consonant stems) vanduo -> sg. vandeniui, pl. vandenims.
Adjectives in the dative case receive pronominal endings (this might be the result of a more recent development): tas geras vaikas -> sg. tam geram vaikui, pl. tiems geriems vaikams.
The dative case in Latvian underwent further simplifications – the original masculine endings of both nouns and adjectives have been replaced with pronominal inflections: tas vīrs -> sg. tam vīram, pl. tiem vīriem. Also, the final "s" in all Dative forms has been dropped. The only exception is personal pronouns in the plural: mums (to us), jums (to you). In colloquial Lithuanian the final "s" in the dative is often omitted, as well: time geriem vaikam.
In both Latvian and Lithuanian, the main function of the dative case is to render the indirect object in a sentence: (lt) aš duodu vyrui knygą; (lv) es dodu [duodu] vīram grāmatu – I am giving a book to the man.
The dative case can also be used with gerundives to indicate an action preceding or simultaneous with the main action in a sentence: (lt) jam įėjus, visi atsistojo – when he walked in, everybody stood up, lit. to him having walked in, all stood up; (lt) jai miegant, visi dirbo – while she slept, everybody was working, lit. to her sleeping, all were working.
In modern standard Lithuanian, Dative case is not required by prepositions, although in many dialects it is done frequently: (dial.) iki (+D) šiai dienai, (stand.) iki (+G) šios dienos – up until this day.
In Latvian, the dative case is taken by several prepositions in the singular and all prepositions in the plural (due to peculiar historical changes): sg. bez (+G) tevis (without thee) ~ pl. bez (+D) jums (without you); sg. pa (+A) ceļu (along the road) ~ pl. pa (+D) ceļiem (along the roads).
In modern Eastern Armenian, the dative is attained by adding any article to the genitive:
There is a general tendency to view -ին as the standard dative suffix, but only because that is its most productive (and therefore common) form. The suffix -ին as a dative marker is nothing but the standard, most common, genitive suffix -ի accompanied by the definite article -ն. But the dative case encompasses indefinite objects as well, which will not be marked by -ին:
The main function of the dative marking in Armenian is to indicate the receiving end of an action, more commonly the indirect object which in English is preceded by the preposition to. In the use of "giving" verbs like give, donate, offer, deliver, sell, bring... the dative marks the recipient. With communicative verbs like tell, say, advise, explain, ask, answer... the dative marks the listener. Other verbs whose indirect objects are marked by the dative case in Armenian are show, reach, look, approach...
Eastern Armenian also uses the dative case to mark the time of an event, in the same way English uses the preposition at, as in Meet me at nine o' clock.
Hindustani (Hindi-Urdu) has true dative case for pronouns, but for nouns the dative case has to be constructed using the dative case-marker (postposition) को کو (ko) to the nouns in their oblique case. Pronouns in Hindustani also have an oblique case, so dative pronouns can also be alternatively constructed using the dative case-marker को کو (ko) with the pronouns in their oblique case, hence forming two sets of synonymous dative pronouns. The following table shows the pronouns in their nominative and their dative forms. Hindustani lacks pronouns in the third person and the demonstrative pronouns double as the third person pronouns.
The table below shows the oblique cases of Hindustani for the nouns boy and girl which take in the dative case-marker after them to assign the combination of the oblique case and the case-marker the dative case. The oblique case of Hindustani by itself has no meaning and adding the case-marker को کو (ko) assigns the oblique case the function of the dative case.
Dative case in Hindustani can also mark the subject of a sentence. This is called the dative construction or quirky subjects. In the examples below the dative pronoun passes the subjecthood test of subject-oriented anaphora binding. The dative subject मुझे مجھے (mujhe) binds the anaphora अपने اپنے (apne).
मुझे
مجھے
mujhei
I.DAT
अपने
اپنے
apnei
REFL.MASC.PL
सभी
سبھی
sabhī
all.NOM
रिश्तेदार
رشتےدار
rishtedār
relatives.MASC.PL
पसंद
پسند
pasand
like
हैं
ہیں
hɛ̄
be.PRS.MASC.PL
मुझे अपने सभी रिश्तेदार पसंद हैं
مجھے اپنے سبھی رشتےدار پسند ہیں
mujhei apnei sabhī rishtedār pasand hɛ̄
I.DAT REFL.MASC.PL all.NOM relatives.MASC.PL like be.PRS.MASC.PL
'I like all my relatives'
मुझे
مجھے
mujhei
I.DAT
अपने
اپنے
apnei
REFL.MASC.PL
काम
کام
kām
work.NOM
करने
کرنے
karne
do.INF.PTCP.MASC.PL
हैं
ہیں
hɛ̄
be.PRS.MASC.PL
मुझे अपने काम करने हैं
مجھے اپنے کام کرنے ہیں
mujhei apnei kām karne hɛ̄
I.DAT REFL.MASC.PL work.NOM do.INF.PTCP.MASC.PL be.PRS.MASC.PL
'I have/want to do my work.'
The dative case is known as the "fourth case" (chaturthi-vibhakti) in the usual procedure in the declension of nouns. Its use is mainly for the indirect object.
As with many other languages, the dative case is used in Hungarian to show the indirect object of a verb. For example, Dánielnek adtam ezt a könyvet (I gave this book to Dániel). It has two suffixes, -nak and -nek; the correct one is selected by vowel harmony. The personal dative pronouns follow the -nek version: nekem, neked, etc. This case is also used to express "for" in certain circumstances, such as "I bought a gift for Mother". In possessive constructions the nak/nek endings are also used but this is not the dative form (rather, the attributive or possessive case)
Finnish does not have a separate dative case. However, the allative case can fulfill essentially the same role as dative, beyond its primary meaning of directional movement (that is, going somewhere or approaching someone). For example: He lahjoittivat kaikki rahansa köyhille (They donated all their money to the poor.)
In the Northeast Caucasian languages, such as Tsez, the dative also takes the functions of the lative case in marking the direction of an action. By some linguists, they are still regarded as two separate cases in those languages, although the suffixes are exactly the same for both cases. Other linguists list them separately only for the purpose of separating syntactic cases from locative cases. An example with the ditransitive verb "show" (literally: "make see") is given below:
Кидбā
kidb-ā
girl:OBL-ERG
ужихъор
uži-qo-r
boy-POSS-DAT/LAT
кIетIу
kʼetʼu
cat:[III]:ABS
биквархо.
b-ikʷa-r-xo
III-see-CAUS-PRES
Кидбā ужихъор кIетIу биквархо.
kidb-ā uži-qo-r kʼetʼu b-ikʷa-r-xo
girl:OBL-ERG boy-POSS-DAT/LAT cat:[III]:ABS III-see-CAUS-PRES
"The girl shows the cat to the boy."
The dative/lative is also used to indicate possession, as in the example below, because there is no such verb as "to have".
Кидбехъор
kidbe-qo-r
girl:OBL-POSS-DAT/LAT
кIетIу
kʼetʼu
cat:ABS
зовси.
zow-si
be:PST-PST
Кидбехъор кIетIу зовси.
kidbe-qo-r kʼetʼu zow-si
girl:OBL-POSS-DAT/LAT cat:ABS be:PST-PST
"The girl had a cat."
As in the examples above, the dative/lative case usually occurs in combination with another suffix as poss-lative case; this should not be regarded as a separate case, however, as many of the locative cases in Tsez are constructed analytically; hence, they are, in fact, a combination of two case suffixes. See Tsez language#Locative case suffixes for further details.
Verbs of perception or emotion (like "see", "know", "love", "want") also require the logical subject to stand in the dative/lative case. In this example the "pure" dative/lative without its POSS-suffix is used.
ГIалир
ʻAli-r
Ali-DAT/LAT
ПатIи
Patʼi
Fatima:[II]:ABS
йетих.
y-eti-x
II-love-PRES
ГIалир ПатIи йетих.
ʻAli-r Patʼi y-eti-x
Ali-DAT/LAT Fatima:[II]:ABS II-love-PRES
"Ali loves Fatima."
The dative case (yönelme durumu) in the Turkish language is formed by adding the ''-e" or "-a'' suffixes to the end of the noun, in accordance with the effected noun's vowel harmony. The word that should be in the dative case can be found as an answer to the questions 'neye?' (to what?), 'kime?' (to whom?) and 'nereye?' (to where?) will lead to find a dative case in a sentence. There are many different uses for the dative case.
The dative also is for objects, usually indirect objects, but sometimes objects that in English would be considered direct:
Güneşin
sun's
batışına
at-its-sinking
bak.
look
Güneşin batışına bak.
sun's at-its-sinking look
"Look at the sunset."
The dative case tells whither, that is, the place to which. Thus it has roughly the meaning of the English prepositions "to" and "into", and also "in" when it can be replaced with "into":
Birayı
the-beer
buzdolabına
into-icebox
koy.
put
Birayı buzdolabına koy.
the-beer into-icebox put
"Put the beer in(to) the fridge." | [
{
"paragraph_id": 0,
"text": "In grammar, the dative case (abbreviated dat, or sometimes d when it is a core argument) is a grammatical case used in some languages to indicate the recipient or beneficiary of an action, as in \"Maria Jacobo potum dedit\", Latin for \"Maria gave Jacob a drink\". In this example, the dative marks what would be considered the indirect object of a verb in English.",
"title": ""
},
{
"paragraph_id": 1,
"text": "Sometimes the dative has functions unrelated to giving. In Scottish Gaelic and Irish, the term dative case is used in traditional grammars to refer to the prepositional case-marking of nouns following simple prepositions and the definite article. In Georgian and Hindustani (Hindi-Urdu), the dative case can also mark the subject of a sentence. This is called the dative construction. In Hindi, the dative construction is not limited to only certain verbs or tenses and it can be used with any verb in any tense or mood.",
"title": ""
},
{
"paragraph_id": 2,
"text": "The dative was common among early Indo-European languages and has survived to the present in the Balto-Slavic branch, the Germanic branch, Albanian and others. It also exists in similar forms in several non-Indo-European languages, such as the Uralic family of languages. In some languages, the dative case has assimilated the functions of other, now extinct cases. In Ancient Greek, the dative has the functions of the Proto-Indo-European locative and instrumental as well as those of the original dative.",
"title": ""
},
{
"paragraph_id": 3,
"text": "Under the influence of English, which uses the preposition \"to\" for (among other uses) both indirect objects (give to) and directions of movement (go to), the term \"dative\" has sometimes been used to describe cases that in other languages would more appropriately be called lative.",
"title": ""
},
{
"paragraph_id": 4,
"text": "\"Dative\" comes from Latin cāsus datīvus (\"case for giving\"), a translation of Greek δοτικὴ πτῶσις, dotikē ptôsis (\"inflection for giving\"). Dionysius Thrax in his Art of Grammar also refers to it as epistaltikḗ \"for sending (a letter)\", from the verb epistéllō \"send to\", a word from the same root as epistle.",
"title": "Etymology"
},
{
"paragraph_id": 5,
"text": "The Old English language had a dative case; however, the English case system gradually fell into disuse during the Middle English period, when the accusative and dative of pronouns merged into a single oblique case that was also used with all prepositions. This conflation of case in Middle and Modern English has led most modern grammarians to discard the \"accusative\" and \"dative\" labels as obsolete in reference to English, often using the term \"objective\" for oblique.",
"title": "English"
},
{
"paragraph_id": 6,
"text": "The dative case is rare in modern English usage, but it can be argued that it survives in a few set expressions. One example is the word \"methinks\", with the meaning \"it seems to me\". It survives in this fixed form from Old English (having undergone, however, phonetic changes with the rest of the language), in which it was constructed as \"[it]\" + \"me\" (the dative case of the personal pronoun) + \"thinks\" (i.e., \"seems\", < Old English þyncan, \"to seem\", a verb closely related to the verb þencan, \"to think\", but distinct from it in Old English; later it merged with \"think\" and lost this meaning).",
"title": "English"
},
{
"paragraph_id": 7,
"text": "The modern objective case pronoun whom is derived from the dative case in Old English, specifically the Old English dative pronoun \"hwām\" (as opposed to the modern subjective \"who\", which descends from Old English \"hwā\") – though \"whom\" also absorbed the functions of the Old English accusative pronoun \"hwone\". It is also cognate to the word \"wem\" (the dative form of \"wer\") in German. The OED defines all classical uses of the word \"whom\" in situations where the indirect object is not known – in effect, indicating the anonymity of the indirect object.",
"title": "English"
},
{
"paragraph_id": 8,
"text": "Likewise, some of the object forms of personal pronouns are remnants of Old English datives. For example, \"him\" goes back to the Old English dative him (accusative was hine), and \"her\" goes back to the dative hire (accusative was hīe). These pronouns are not pure datives in modern English; they are also used for functions previously indicated by the accusative.",
"title": "English"
},
{
"paragraph_id": 9,
"text": "The indirect object of the verb may be placed between the verb and the direct object of the verb: \"he gave me a book\" or \"he wrote me a poem.\"",
"title": "English"
},
{
"paragraph_id": 10,
"text": "The indirect object may also be expressed using a prepositional phrase using \"to\": \"he gave a book to me.",
"title": "English"
},
{
"paragraph_id": 11,
"text": "In general, the dative (German: Dativ) is used to mark the indirect object of a German sentence. For example:",
"title": "German"
},
{
"paragraph_id": 12,
"text": "In English, the first sentence can be rendered as \"I sent the book to the man\" and as \"I sent the man the book\", where the indirect object is identified in English by standing in front of the direct object. The normal word order in German is to put the dative in front of the accusative (as in the example above). However, since the German dative is marked in form, it can also be put after the accusative: Ich schickte das Buch dem Mann(e). The (e) after Mann and Kind signifies a now largely archaic -e ending for certain nouns in the dative. It survives today almost exclusively in set phrases such as zu Hause (at home, lit. to house), im Zuge (in the course of), and am Tage (during the day, lit. at the day), as well as in occasional usage in formal prose, poetry, and song lyrics.",
"title": "German"
},
{
"paragraph_id": 13,
"text": "Some masculine nouns (and one neuter noun, Herz [heart]), referred to as weak nouns or n-nouns, take an -n or -en in the dative singular and plural. Many are masculine nouns ending in -e in the nominative (such as Name [name], Beamte [officer], and Junge [boy]), although not all such nouns follow this rule. Many also, whether or not they fall into the former category, refer to people, animals, professions, or titles; exceptions to this include the aforementioned Herz and Name, as well as Buchstabe (letter), Friede (peace), Obelisk (obelisk), Planet (planet), and others.",
"title": "German"
},
{
"paragraph_id": 14,
"text": "Certain German prepositions require the dative: aus (from), außer (out of), bei (at, near), entgegen (against), gegenüber (opposite), mit (with), nach (after, to), seit (since), von (from), and zu (at, in, to). Some other prepositions (an [at], auf [on], entlang [along], hinter [behind], in [in, into], neben (beside, next to), über [over, across], unter [under, below], vor [in front of], and zwischen [among, between]) may be used with dative (indicating current location), or accusative (indicating direction toward something). Das Buch liegt auf dem Tisch(e) (dative: The book is lying on the table), but Ich lege das Buch auf den Tisch (accusative: I put the book onto the table).",
"title": "German"
},
{
"paragraph_id": 15,
"text": "In addition the four prepositions [an]statt (in place of), trotz (in spite of), während (during), and wegen (because of) which require the genitive in modern formal language, are most commonly used with the dative in colloquial German. For example, \"because of the weather\" is expressed as wegen dem Wetter instead of the formally correct wegen des Wetters. Other prepositions requiring the genitive in formal language, are combined with von (\"of\") in colloquial style, e.g. außerhalb vom Garten instead of außerhalb des Gartens (\"outside the garden\").",
"title": "German"
},
{
"paragraph_id": 16,
"text": "The concept of an indirect object may be rendered by a prepositional phrase. In this case, the noun's or pronoun's case is determined by the preposition, not by its function in the sentence. Consider this sentence:",
"title": "German"
},
{
"paragraph_id": 17,
"text": "Here, the subject, Ich, is in the nominative case, the direct object, das Buch, is in the accusative case, and zum Verleger is in the dative case, since zu always requires the dative (zum is a contraction of zu + dem). However:",
"title": "German"
},
{
"paragraph_id": 18,
"text": "In this sentence, Freund is the indirect object, but, because it follows an (direction), the accusative is required, not the dative.",
"title": "German"
},
{
"paragraph_id": 19,
"text": "All of the articles change in the dative case.",
"title": "German"
},
{
"paragraph_id": 20,
"text": "Some German verbs require the dative for their direct objects. Common examples are antworten (to answer), danken (to thank), gefallen (to please), folgen (to follow), glauben (to believe), helfen (to help), and raten (to advise). In each case, the direct object of the verb is rendered in the dative. For example:",
"title": "German"
},
{
"paragraph_id": 21,
"text": "These verbs cannot be used in normal passive constructions, because German allows these only for verbs with accusative objects. It is therefore ungrammatical to say: *Ich werde geholfen. \"I am helped.\" Instead a special construction called \"impersonal passive\" must be used: Mir wird geholfen, literally: \"To me is helped.\" A colloquial (non-standard) way to form the passive voice for dative verbs is the following: Ich kriege geholfen, or: Ich bekomme geholfen, literally: \"I get helped\". The use of the verb \"to get\" here reminds us that the dative case has something to do with giving and receiving. In German, help is not something you perform on somebody, but rather something you offer them.",
"title": "German"
},
{
"paragraph_id": 22,
"text": "The dative case is also used with reflexive (sich) verbs when specifying what part of the self the verb is being done to:",
"title": "German"
},
{
"paragraph_id": 23,
"text": "Cf. the respective accord in French: \"Les enfants se sont lavés\" (the children have washed themselves) vs. \"Les enfants se sont lavé\" [uninflected] \"les mains\" (... their hands).",
"title": "German"
},
{
"paragraph_id": 24,
"text": "German can use two datives to make sentences like: Sei mir meinem Sohn(e) gnädig! \"For my sake, have mercy on my son!\" Literally: \"Be for me to my son merciful.\" The first dative mir (\"for me\") expresses the speaker's commiseration (much like the dativus ethicus in Latin, see below). The second dative meinem Sohn(e) (\"to my son\") names the actual object of the plea. Mercy is to be given to the son for or on behalf of his mother/father.",
"title": "German"
},
{
"paragraph_id": 25,
"text": "Adjective endings also change in the dative case. There are three inflection possibilities depending on what precedes the adjective. They most commonly use weak inflection when preceded by a definite article (the), mixed inflection after an indefinite article (a/an), and strong inflection when a quantity is indicated (many green apples).",
"title": "German"
},
{
"paragraph_id": 26,
"text": "There are several uses for the dative case (Dativus):",
"title": "Latin"
},
{
"paragraph_id": 27,
"text": "In addition to its main function as the dativus, the dative case has other functions in Classical Greek: (The chart below uses the Latin names for the types of dative; the Greek name for the dative is δοτική πτῶσις, like its Latin equivalent, derived from the verb \"to give\"; in Ancient Greek, δίδωμι.)",
"title": "Greek"
},
{
"paragraph_id": 28,
"text": "The articles in the Greek dative are",
"title": "Greek"
},
{
"paragraph_id": 29,
"text": "The dative case, strictly speaking, no longer exists in Modern Greek, except in fossilized expressions like δόξα τω Θεώ (from the ecclesiastical τῷ Θεῷ δόξα, \"Glory to God\") or εν τάξει (ἐν τάξει, lit. \"in order\", i.e. \"all right\" or \"OK\"). Otherwise, most of the functions of the dative are expressed by the genitive or by prepositional phrases.",
"title": "Greek"
},
{
"paragraph_id": 30,
"text": "In Russian, the dative case is used for indicating the indirect object of an action (that to which something is given, thrown, read, etc.). In the instance where a person is the goal of motion, dative is used instead of accusative to indicate motion toward. This is usually achieved with the preposition κ + destination in dative case; К врачу, meaning \"to the doctor.\"",
"title": "Slavic languages"
},
{
"paragraph_id": 31,
"text": "Dative is also the necessary case taken by certain prepositions when expressing certain ideas. For instance, when the preposition по is used to mean \"along\", its object is always in dative case, as in По бокам, meaning \"along the sides.\"",
"title": "Slavic languages"
},
{
"paragraph_id": 32,
"text": "Other Slavic languages apply the dative case (and the other cases) more or less the same way as does Russian; some languages may use the dative in other ways. The following examples are from Polish:",
"title": "Slavic languages"
},
{
"paragraph_id": 33,
"text": "Some other kinds of dative use as found in the Serbo-Croatian language are: Dativus finalis (Titaniku u pomoć \"to Titanic's rescue\"), Dativus commodi/incommodi (Operi svojoj majci suđe \"Wash the dishes for your mother\"), Dativus possessivus (Ovcama je dlaka gusta \"Sheep's hair is thick\"), Dativus ethicus (Šta/što mi radi Boni? \"What is Boni doing? (I am especially interested in what it is)\") and Dativus auctoris (Izgleda mi okej \"It seems okay to me\").",
"title": "Slavic languages"
},
{
"paragraph_id": 34,
"text": "Unusual in other Indo-European branches but common among Slavic languages, endings of nouns and adjectives are different based on grammatical function. Other factors are gender and number. In some cases, the ending may not be obvious, even when those three factors (function, gender, number) are considered. For example, in Polish, 'syn' (\"son\") and 'ojciec' (\"father\") are both masculine singular nouns, yet appear as syn → synowi and ojciec → ojcu in the dative.",
"title": "Slavic languages"
},
{
"paragraph_id": 35,
"text": "Both Lithuanian and Latvian have a distinct dative case in the system of nominal declensions.",
"title": "Baltic languages"
},
{
"paragraph_id": 36,
"text": "Lithuanian nouns preserve Indo-European inflections in the dative case fairly well: (o-stems) vaikas -> sg. vaikui, pl. vaikams; (ā-stems) ranka -> sg. rankai, pl. rankoms; (i-stems) viltis -> sg. vilčiai, pl. viltims; (u-stems) sūnus -> sg. sūnui, pl. sūnums; (consonant stems) vanduo -> sg. vandeniui, pl. vandenims.",
"title": "Baltic languages"
},
{
"paragraph_id": 37,
"text": "Adjectives in the dative case receive pronominal endings (this might be the result of a more recent development): tas geras vaikas -> sg. tam geram vaikui, pl. tiems geriems vaikams.",
"title": "Baltic languages"
},
{
"paragraph_id": 38,
"text": "The dative case in Latvian underwent further simplifications – the original masculine endings of both nouns and adjectives have been replaced with pronominal inflections: tas vīrs -> sg. tam vīram, pl. tiem vīriem. Also, the final \"s\" in all Dative forms has been dropped. The only exception is personal pronouns in the plural: mums (to us), jums (to you). In colloquial Lithuanian the final \"s\" in the dative is often omitted, as well: time geriem vaikam.",
"title": "Baltic languages"
},
{
"paragraph_id": 39,
"text": "In both Latvian and Lithuanian, the main function of the dative case is to render the indirect object in a sentence: (lt) aš duodu vyrui knygą; (lv) es dodu [duodu] vīram grāmatu – I am giving a book to the man.",
"title": "Baltic languages"
},
{
"paragraph_id": 40,
"text": "The dative case can also be used with gerundives to indicate an action preceding or simultaneous with the main action in a sentence: (lt) jam įėjus, visi atsistojo – when he walked in, everybody stood up, lit. to him having walked in, all stood up; (lt) jai miegant, visi dirbo – while she slept, everybody was working, lit. to her sleeping, all were working.",
"title": "Baltic languages"
},
{
"paragraph_id": 41,
"text": "In modern standard Lithuanian, Dative case is not required by prepositions, although in many dialects it is done frequently: (dial.) iki (+D) šiai dienai, (stand.) iki (+G) šios dienos – up until this day.",
"title": "Baltic languages"
},
{
"paragraph_id": 42,
"text": "In Latvian, the dative case is taken by several prepositions in the singular and all prepositions in the plural (due to peculiar historical changes): sg. bez (+G) tevis (without thee) ~ pl. bez (+D) jums (without you); sg. pa (+A) ceļu (along the road) ~ pl. pa (+D) ceļiem (along the roads).",
"title": "Baltic languages"
},
{
"paragraph_id": 43,
"text": "",
"title": "Armenian"
},
{
"paragraph_id": 44,
"text": "In modern Eastern Armenian, the dative is attained by adding any article to the genitive:",
"title": "Armenian"
},
{
"paragraph_id": 45,
"text": "There is a general tendency to view -ին as the standard dative suffix, but only because that is its most productive (and therefore common) form. The suffix -ին as a dative marker is nothing but the standard, most common, genitive suffix -ի accompanied by the definite article -ն. But the dative case encompasses indefinite objects as well, which will not be marked by -ին:",
"title": "Armenian"
},
{
"paragraph_id": 46,
"text": "The main function of the dative marking in Armenian is to indicate the receiving end of an action, more commonly the indirect object which in English is preceded by the preposition to. In the use of \"giving\" verbs like give, donate, offer, deliver, sell, bring... the dative marks the recipient. With communicative verbs like tell, say, advise, explain, ask, answer... the dative marks the listener. Other verbs whose indirect objects are marked by the dative case in Armenian are show, reach, look, approach...",
"title": "Armenian"
},
{
"paragraph_id": 47,
"text": "Eastern Armenian also uses the dative case to mark the time of an event, in the same way English uses the preposition at, as in Meet me at nine o' clock.",
"title": "Armenian"
},
{
"paragraph_id": 48,
"text": "Hindustani (Hindi-Urdu) has true dative case for pronouns, but for nouns the dative case has to be constructed using the dative case-marker (postposition) को کو (ko) to the nouns in their oblique case. Pronouns in Hindustani also have an oblique case, so dative pronouns can also be alternatively constructed using the dative case-marker को کو (ko) with the pronouns in their oblique case, hence forming two sets of synonymous dative pronouns. The following table shows the pronouns in their nominative and their dative forms. Hindustani lacks pronouns in the third person and the demonstrative pronouns double as the third person pronouns.",
"title": "Indo-Aryan languages"
},
{
"paragraph_id": 49,
"text": "The table below shows the oblique cases of Hindustani for the nouns boy and girl which take in the dative case-marker after them to assign the combination of the oblique case and the case-marker the dative case. The oblique case of Hindustani by itself has no meaning and adding the case-marker को کو (ko) assigns the oblique case the function of the dative case.",
"title": "Indo-Aryan languages"
},
{
"paragraph_id": 50,
"text": "Dative case in Hindustani can also mark the subject of a sentence. This is called the dative construction or quirky subjects. In the examples below the dative pronoun passes the subjecthood test of subject-oriented anaphora binding. The dative subject मुझे مجھے (mujhe) binds the anaphora अपने اپنے (apne).",
"title": "Indo-Aryan languages"
},
{
"paragraph_id": 51,
"text": "मुझे",
"title": "Indo-Aryan languages"
},
{
"paragraph_id": 52,
"text": "مجھے",
"title": "Indo-Aryan languages"
},
{
"paragraph_id": 53,
"text": "mujhei",
"title": "Indo-Aryan languages"
},
{
"paragraph_id": 54,
"text": "I.DAT",
"title": "Indo-Aryan languages"
},
{
"paragraph_id": 55,
"text": "अपने",
"title": "Indo-Aryan languages"
},
{
"paragraph_id": 56,
"text": "اپنے",
"title": "Indo-Aryan languages"
},
{
"paragraph_id": 57,
"text": "apnei",
"title": "Indo-Aryan languages"
},
{
"paragraph_id": 58,
"text": "REFL.MASC.PL",
"title": "Indo-Aryan languages"
},
{
"paragraph_id": 59,
"text": "सभी",
"title": "Indo-Aryan languages"
},
{
"paragraph_id": 60,
"text": "سبھی",
"title": "Indo-Aryan languages"
},
{
"paragraph_id": 61,
"text": "sabhī",
"title": "Indo-Aryan languages"
},
{
"paragraph_id": 62,
"text": "all.NOM",
"title": "Indo-Aryan languages"
},
{
"paragraph_id": 63,
"text": "रिश्तेदार",
"title": "Indo-Aryan languages"
},
{
"paragraph_id": 64,
"text": "رشتےدار",
"title": "Indo-Aryan languages"
},
{
"paragraph_id": 65,
"text": "rishtedār",
"title": "Indo-Aryan languages"
},
{
"paragraph_id": 66,
"text": "relatives.MASC.PL",
"title": "Indo-Aryan languages"
},
{
"paragraph_id": 67,
"text": "पसंद",
"title": "Indo-Aryan languages"
},
{
"paragraph_id": 68,
"text": "پسند",
"title": "Indo-Aryan languages"
},
{
"paragraph_id": 69,
"text": "pasand",
"title": "Indo-Aryan languages"
},
{
"paragraph_id": 70,
"text": "like",
"title": "Indo-Aryan languages"
},
{
"paragraph_id": 71,
"text": "हैं",
"title": "Indo-Aryan languages"
},
{
"paragraph_id": 72,
"text": "ہیں",
"title": "Indo-Aryan languages"
},
{
"paragraph_id": 73,
"text": "hɛ̄",
"title": "Indo-Aryan languages"
},
{
"paragraph_id": 74,
"text": "be.PRS.MASC.PL",
"title": "Indo-Aryan languages"
},
{
"paragraph_id": 75,
"text": "मुझे अपने सभी रिश्तेदार पसंद हैं",
"title": "Indo-Aryan languages"
},
{
"paragraph_id": 76,
"text": "مجھے اپنے سبھی رشتےدار پسند ہیں",
"title": "Indo-Aryan languages"
},
{
"paragraph_id": 77,
"text": "mujhei apnei sabhī rishtedār pasand hɛ̄",
"title": "Indo-Aryan languages"
},
{
"paragraph_id": 78,
"text": "I.DAT REFL.MASC.PL all.NOM relatives.MASC.PL like be.PRS.MASC.PL",
"title": "Indo-Aryan languages"
},
{
"paragraph_id": 79,
"text": "'I like all my relatives'",
"title": "Indo-Aryan languages"
},
{
"paragraph_id": 80,
"text": "मुझे",
"title": "Indo-Aryan languages"
},
{
"paragraph_id": 81,
"text": "مجھے",
"title": "Indo-Aryan languages"
},
{
"paragraph_id": 82,
"text": "mujhei",
"title": "Indo-Aryan languages"
},
{
"paragraph_id": 83,
"text": "I.DAT",
"title": "Indo-Aryan languages"
},
{
"paragraph_id": 84,
"text": "अपने",
"title": "Indo-Aryan languages"
},
{
"paragraph_id": 85,
"text": "اپنے",
"title": "Indo-Aryan languages"
},
{
"paragraph_id": 86,
"text": "apnei",
"title": "Indo-Aryan languages"
},
{
"paragraph_id": 87,
"text": "REFL.MASC.PL",
"title": "Indo-Aryan languages"
},
{
"paragraph_id": 88,
"text": "काम",
"title": "Indo-Aryan languages"
},
{
"paragraph_id": 89,
"text": "کام",
"title": "Indo-Aryan languages"
},
{
"paragraph_id": 90,
"text": "kām",
"title": "Indo-Aryan languages"
},
{
"paragraph_id": 91,
"text": "work.NOM",
"title": "Indo-Aryan languages"
},
{
"paragraph_id": 92,
"text": "करने",
"title": "Indo-Aryan languages"
},
{
"paragraph_id": 93,
"text": "کرنے",
"title": "Indo-Aryan languages"
},
{
"paragraph_id": 94,
"text": "karne",
"title": "Indo-Aryan languages"
},
{
"paragraph_id": 95,
"text": "do.INF.PTCP.MASC.PL",
"title": "Indo-Aryan languages"
},
{
"paragraph_id": 96,
"text": "हैं",
"title": "Indo-Aryan languages"
},
{
"paragraph_id": 97,
"text": "ہیں",
"title": "Indo-Aryan languages"
},
{
"paragraph_id": 98,
"text": "hɛ̄",
"title": "Indo-Aryan languages"
},
{
"paragraph_id": 99,
"text": "be.PRS.MASC.PL",
"title": "Indo-Aryan languages"
},
{
"paragraph_id": 100,
"text": "मुझे अपने काम करने हैं",
"title": "Indo-Aryan languages"
},
{
"paragraph_id": 101,
"text": "مجھے اپنے کام کرنے ہیں",
"title": "Indo-Aryan languages"
},
{
"paragraph_id": 102,
"text": "mujhei apnei kām karne hɛ̄",
"title": "Indo-Aryan languages"
},
{
"paragraph_id": 103,
"text": "I.DAT REFL.MASC.PL work.NOM do.INF.PTCP.MASC.PL be.PRS.MASC.PL",
"title": "Indo-Aryan languages"
},
{
"paragraph_id": 104,
"text": "'I have/want to do my work.'",
"title": "Indo-Aryan languages"
},
{
"paragraph_id": 105,
"text": "The dative case is known as the \"fourth case\" (chaturthi-vibhakti) in the usual procedure in the declension of nouns. Its use is mainly for the indirect object.",
"title": "Indo-Aryan languages"
},
{
"paragraph_id": 106,
"text": "As with many other languages, the dative case is used in Hungarian to show the indirect object of a verb. For example, Dánielnek adtam ezt a könyvet (I gave this book to Dániel). It has two suffixes, -nak and -nek; the correct one is selected by vowel harmony. The personal dative pronouns follow the -nek version: nekem, neked, etc. This case is also used to express \"for\" in certain circumstances, such as \"I bought a gift for Mother\". In possessive constructions the nak/nek endings are also used but this is not the dative form (rather, the attributive or possessive case)",
"title": "Non-Indo-European languages"
},
{
"paragraph_id": 107,
"text": "Finnish does not have a separate dative case. However, the allative case can fulfill essentially the same role as dative, beyond its primary meaning of directional movement (that is, going somewhere or approaching someone). For example: He lahjoittivat kaikki rahansa köyhille (They donated all their money to the poor.)",
"title": "Non-Indo-European languages"
},
{
"paragraph_id": 108,
"text": "In the Northeast Caucasian languages, such as Tsez, the dative also takes the functions of the lative case in marking the direction of an action. By some linguists, they are still regarded as two separate cases in those languages, although the suffixes are exactly the same for both cases. Other linguists list them separately only for the purpose of separating syntactic cases from locative cases. An example with the ditransitive verb \"show\" (literally: \"make see\") is given below:",
"title": "Non-Indo-European languages"
},
{
"paragraph_id": 109,
"text": "Кидбā",
"title": "Non-Indo-European languages"
},
{
"paragraph_id": 110,
"text": "kidb-ā",
"title": "Non-Indo-European languages"
},
{
"paragraph_id": 111,
"text": "girl:OBL-ERG",
"title": "Non-Indo-European languages"
},
{
"paragraph_id": 112,
"text": "ужихъор",
"title": "Non-Indo-European languages"
},
{
"paragraph_id": 113,
"text": "uži-qo-r",
"title": "Non-Indo-European languages"
},
{
"paragraph_id": 114,
"text": "boy-POSS-DAT/LAT",
"title": "Non-Indo-European languages"
},
{
"paragraph_id": 115,
"text": "кIетIу",
"title": "Non-Indo-European languages"
},
{
"paragraph_id": 116,
"text": "kʼetʼu",
"title": "Non-Indo-European languages"
},
{
"paragraph_id": 117,
"text": "cat:[III]:ABS",
"title": "Non-Indo-European languages"
},
{
"paragraph_id": 118,
"text": "биквархо.",
"title": "Non-Indo-European languages"
},
{
"paragraph_id": 119,
"text": "b-ikʷa-r-xo",
"title": "Non-Indo-European languages"
},
{
"paragraph_id": 120,
"text": "III-see-CAUS-PRES",
"title": "Non-Indo-European languages"
},
{
"paragraph_id": 121,
"text": "Кидбā ужихъор кIетIу биквархо.",
"title": "Non-Indo-European languages"
},
{
"paragraph_id": 122,
"text": "kidb-ā uži-qo-r kʼetʼu b-ikʷa-r-xo",
"title": "Non-Indo-European languages"
},
{
"paragraph_id": 123,
"text": "girl:OBL-ERG boy-POSS-DAT/LAT cat:[III]:ABS III-see-CAUS-PRES",
"title": "Non-Indo-European languages"
},
{
"paragraph_id": 124,
"text": "\"The girl shows the cat to the boy.\"",
"title": "Non-Indo-European languages"
},
{
"paragraph_id": 125,
"text": "The dative/lative is also used to indicate possession, as in the example below, because there is no such verb as \"to have\".",
"title": "Non-Indo-European languages"
},
{
"paragraph_id": 126,
"text": "Кидбехъор",
"title": "Non-Indo-European languages"
},
{
"paragraph_id": 127,
"text": "kidbe-qo-r",
"title": "Non-Indo-European languages"
},
{
"paragraph_id": 128,
"text": "girl:OBL-POSS-DAT/LAT",
"title": "Non-Indo-European languages"
},
{
"paragraph_id": 129,
"text": "кIетIу",
"title": "Non-Indo-European languages"
},
{
"paragraph_id": 130,
"text": "kʼetʼu",
"title": "Non-Indo-European languages"
},
{
"paragraph_id": 131,
"text": "cat:ABS",
"title": "Non-Indo-European languages"
},
{
"paragraph_id": 132,
"text": "зовси.",
"title": "Non-Indo-European languages"
},
{
"paragraph_id": 133,
"text": "zow-si",
"title": "Non-Indo-European languages"
},
{
"paragraph_id": 134,
"text": "be:PST-PST",
"title": "Non-Indo-European languages"
},
{
"paragraph_id": 135,
"text": "Кидбехъор кIетIу зовси.",
"title": "Non-Indo-European languages"
},
{
"paragraph_id": 136,
"text": "kidbe-qo-r kʼetʼu zow-si",
"title": "Non-Indo-European languages"
},
{
"paragraph_id": 137,
"text": "girl:OBL-POSS-DAT/LAT cat:ABS be:PST-PST",
"title": "Non-Indo-European languages"
},
{
"paragraph_id": 138,
"text": "\"The girl had a cat.\"",
"title": "Non-Indo-European languages"
},
{
"paragraph_id": 139,
"text": "As in the examples above, the dative/lative case usually occurs in combination with another suffix as poss-lative case; this should not be regarded as a separate case, however, as many of the locative cases in Tsez are constructed analytically; hence, they are, in fact, a combination of two case suffixes. See Tsez language#Locative case suffixes for further details.",
"title": "Non-Indo-European languages"
},
{
"paragraph_id": 140,
"text": "Verbs of perception or emotion (like \"see\", \"know\", \"love\", \"want\") also require the logical subject to stand in the dative/lative case. In this example the \"pure\" dative/lative without its POSS-suffix is used.",
"title": "Non-Indo-European languages"
},
{
"paragraph_id": 141,
"text": "ГIалир",
"title": "Non-Indo-European languages"
},
{
"paragraph_id": 142,
"text": "ʻAli-r",
"title": "Non-Indo-European languages"
},
{
"paragraph_id": 143,
"text": "Ali-DAT/LAT",
"title": "Non-Indo-European languages"
},
{
"paragraph_id": 144,
"text": "ПатIи",
"title": "Non-Indo-European languages"
},
{
"paragraph_id": 145,
"text": "Patʼi",
"title": "Non-Indo-European languages"
},
{
"paragraph_id": 146,
"text": "Fatima:[II]:ABS",
"title": "Non-Indo-European languages"
},
{
"paragraph_id": 147,
"text": "йетих.",
"title": "Non-Indo-European languages"
},
{
"paragraph_id": 148,
"text": "y-eti-x",
"title": "Non-Indo-European languages"
},
{
"paragraph_id": 149,
"text": "II-love-PRES",
"title": "Non-Indo-European languages"
},
{
"paragraph_id": 150,
"text": "ГIалир ПатIи йетих.",
"title": "Non-Indo-European languages"
},
{
"paragraph_id": 151,
"text": "ʻAli-r Patʼi y-eti-x",
"title": "Non-Indo-European languages"
},
{
"paragraph_id": 152,
"text": "Ali-DAT/LAT Fatima:[II]:ABS II-love-PRES",
"title": "Non-Indo-European languages"
},
{
"paragraph_id": 153,
"text": "\"Ali loves Fatima.\"",
"title": "Non-Indo-European languages"
},
{
"paragraph_id": 154,
"text": "The dative case (yönelme durumu) in the Turkish language is formed by adding the ''-e\" or \"-a'' suffixes to the end of the noun, in accordance with the effected noun's vowel harmony. The word that should be in the dative case can be found as an answer to the questions 'neye?' (to what?), 'kime?' (to whom?) and 'nereye?' (to where?) will lead to find a dative case in a sentence. There are many different uses for the dative case.",
"title": "Non-Indo-European languages"
},
{
"paragraph_id": 155,
"text": "The dative also is for objects, usually indirect objects, but sometimes objects that in English would be considered direct:",
"title": "Non-Indo-European languages"
},
{
"paragraph_id": 156,
"text": "Güneşin",
"title": "Non-Indo-European languages"
},
{
"paragraph_id": 157,
"text": "sun's",
"title": "Non-Indo-European languages"
},
{
"paragraph_id": 158,
"text": "batışına",
"title": "Non-Indo-European languages"
},
{
"paragraph_id": 159,
"text": "at-its-sinking",
"title": "Non-Indo-European languages"
},
{
"paragraph_id": 160,
"text": "bak.",
"title": "Non-Indo-European languages"
},
{
"paragraph_id": 161,
"text": "look",
"title": "Non-Indo-European languages"
},
{
"paragraph_id": 162,
"text": "Güneşin batışına bak.",
"title": "Non-Indo-European languages"
},
{
"paragraph_id": 163,
"text": "sun's at-its-sinking look",
"title": "Non-Indo-European languages"
},
{
"paragraph_id": 164,
"text": "\"Look at the sunset.\"",
"title": "Non-Indo-European languages"
},
{
"paragraph_id": 165,
"text": "The dative case tells whither, that is, the place to which. Thus it has roughly the meaning of the English prepositions \"to\" and \"into\", and also \"in\" when it can be replaced with \"into\":",
"title": "Non-Indo-European languages"
},
{
"paragraph_id": 166,
"text": "Birayı",
"title": "Non-Indo-European languages"
},
{
"paragraph_id": 167,
"text": "the-beer",
"title": "Non-Indo-European languages"
},
{
"paragraph_id": 168,
"text": "buzdolabına",
"title": "Non-Indo-European languages"
},
{
"paragraph_id": 169,
"text": "into-icebox",
"title": "Non-Indo-European languages"
},
{
"paragraph_id": 170,
"text": "koy.",
"title": "Non-Indo-European languages"
},
{
"paragraph_id": 171,
"text": "put",
"title": "Non-Indo-European languages"
},
{
"paragraph_id": 172,
"text": "Birayı buzdolabına koy.",
"title": "Non-Indo-European languages"
},
{
"paragraph_id": 173,
"text": "the-beer into-icebox put",
"title": "Non-Indo-European languages"
},
{
"paragraph_id": 174,
"text": "\"Put the beer in(to) the fridge.\"",
"title": "Non-Indo-European languages"
}
] | In grammar, the dative case is a grammatical case used in some languages to indicate the recipient or beneficiary of an action, as in "Maria Jacobo potum dedit", Latin for "Maria gave Jacob a drink". In this example, the dative marks what would be considered the indirect object of a verb in English. Sometimes the dative has functions unrelated to giving. In Scottish Gaelic and Irish, the term dative case is used in traditional grammars to refer to the prepositional case-marking of nouns following simple prepositions and the definite article. In Georgian and Hindustani (Hindi-Urdu), the dative case can also mark the subject of a sentence. This is called the dative construction. In Hindi, the dative construction is not limited to only certain verbs or tenses and it can be used with any verb in any tense or mood. The dative was common among early Indo-European languages and has survived to the present in the Balto-Slavic branch, the Germanic branch, Albanian and others. It also exists in similar forms in several non-Indo-European languages, such as the Uralic family of languages. In some languages, the dative case has assimilated the functions of other, now extinct cases. In Ancient Greek, the dative has the functions of the Proto-Indo-European locative and instrumental as well as those of the original dative. Under the influence of English, which uses the preposition "to" for both indirect objects and directions of movement, the term "dative" has sometimes been used to describe cases that in other languages would more appropriately be called lative. | 2001-10-23T10:33:06Z | 2023-09-28T15:17:50Z | [
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] | https://en.wikipedia.org/wiki/Dative_case |
8,407 | Dodecahedron | In geometry, a dodecahedron (from Ancient Greek δωδεκάεδρον (dōdekáedron); from δώδεκα (dṓdeka) 'twelve', and ἕδρα (hédra) 'base, seat, face') or duodecahedron is any polyhedron with twelve flat faces. The most familiar dodecahedron is the regular dodecahedron with regular pentagons as faces, which is a Platonic solid. There are also three regular star dodecahedra, which are constructed as stellations of the convex form. All of these have icosahedral symmetry, order 120.
Some dodecahedra have the same combinatorial structure as the regular dodecahedron (in terms of the graph formed by its vertices and edges), but their pentagonal faces are not regular: The pyritohedron, a common crystal form in pyrite, has pyritohedral symmetry, while the tetartoid has tetrahedral symmetry.
The rhombic dodecahedron can be seen as a limiting case of the pyritohedron, and it has octahedral symmetry. The elongated dodecahedron and trapezo-rhombic dodecahedron variations, along with the rhombic dodecahedra, are space-filling. There are numerous other dodecahedra.
While the regular dodecahedron shares many features with other Platonic solids, one unique property of it is that one can start at a corner of the surface and draw an infinite number of straight lines across the figure that return to the original point without crossing over any other corner.
The convex regular dodecahedron is one of the five regular Platonic solids and can be represented by its Schläfli symbol {5, 3}.
The dual polyhedron is the regular icosahedron {3, 5}, having five equilateral triangles around each vertex.
The convex regular dodecahedron also has three stellations, all of which are regular star dodecahedra. They form three of the four Kepler–Poinsot polyhedra. They are the small stellated dodecahedron {5/2, 5}, the great dodecahedron {5, 5/2}, and the great stellated dodecahedron {5/2, 3}. The small stellated dodecahedron and great dodecahedron are dual to each other; the great stellated dodecahedron is dual to the great icosahedron {3, 5/2}. All of these regular star dodecahedra have regular pentagonal or pentagrammic faces. The convex regular dodecahedron and great stellated dodecahedron are different realisations of the same abstract regular polyhedron; the small stellated dodecahedron and great dodecahedron are different realisations of another abstract regular polyhedron.
In crystallography, two important dodecahedra can occur as crystal forms in some symmetry classes of the cubic crystal system that are topologically equivalent to the regular dodecahedron but less symmetrical: the pyritohedron with pyritohedral symmetry, and the tetartoid with tetrahedral symmetry:
A pyritohedron is a dodecahedron with pyritohedral (Th) symmetry. Like the regular dodecahedron, it has twelve identical pentagonal faces, with three meeting in each of the 20 vertices (see figure). However, the pentagons are not constrained to be regular, and the underlying atomic arrangement has no true fivefold symmetry axis. Its 30 edges are divided into two sets – containing 24 and 6 edges of the same length. The only axes of rotational symmetry are three mutually perpendicular twofold axes and four threefold axes.
Although regular dodecahedra do not exist in crystals, the pyritohedron form occurs in the crystals of the mineral pyrite, and it may be an inspiration for the discovery of the regular Platonic solid form. The true regular dodecahedron can occur as a shape for quasicrystals (such as holmium–magnesium–zinc quasicrystal) with icosahedral symmetry, which includes true fivefold rotation axes.
The name crystal pyrite comes from one of the two common crystal habits shown by pyrite (the other one being the cube). In pyritohedral pyrite, the faces have a Miller index of (210), which means that the dihedral angle is 2·arctan(2) ≈ 126.87° and each pentagonal face has one angle of approximately 121.6° in between two angles of approximately 106.6° and opposite two angles of approximately 102.6°. The following formulas show the measurements for the face of a perfect crystal (which is rarely found in nature).
Height = 5 2 ⋅ Long side {\displaystyle {\text{Height}}={\frac {\sqrt {5}}{2}}\cdot {\text{Long side}}}
Width = 4 3 ⋅ Long side {\displaystyle {\text{Width}}={\frac {4}{3}}\cdot {\text{Long side}}}
Short sides = 7 12 ⋅ Long side {\displaystyle {\text{Short sides}}={\sqrt {\frac {7}{12}}}\cdot {\text{Long side}}}
The eight vertices of a cube have the coordinates (±1, ±1, ±1).
The coordinates of the 12 additional vertices are (0, ±(1 + h), ±(1 − h)), (±(1 + h), ±(1 − h), 0) and (±(1 − h), 0, ±(1 + h)).
h is the height of the wedge-shaped "roof" above the faces of that cube with edge length 2.
An important case is h = 1/2 (a quarter of the cube edge length) for perfect natural pyrite (also the pyritohedron in the Weaire–Phelan structure).
Another one is h = 1/φ = 0.618... for the regular dodecahedron. See section Geometric freedom for other cases.
Two pyritohedra with swapped nonzero coordinates are in dual positions to each other like the dodecahedra in the compound of two dodecahedra.
The pyritohedron has a geometric degree of freedom with limiting cases of a cubic convex hull at one limit of collinear edges, and a rhombic dodecahedron as the other limit as 6 edges are degenerated to length zero. The regular dodecahedron represents a special intermediate case where all edges and angles are equal.
It is possible to go past these limiting cases, creating concave or nonconvex pyritohedra. The endo-dodecahedron is concave and equilateral; it can tessellate space with the convex regular dodecahedron. Continuing from there in that direction, we pass through a degenerate case where twelve vertices coincide in the centre, and on to the regular great stellated dodecahedron where all edges and angles are equal again, and the faces have been distorted into regular pentagrams. On the other side, past the rhombic dodecahedron, we get a nonconvex equilateral dodecahedron with fish-shaped self-intersecting equilateral pentagonal faces.
A tetartoid (also tetragonal pentagonal dodecahedron, pentagon-tritetrahedron, and tetrahedric pentagon dodecahedron) is a dodecahedron with chiral tetrahedral symmetry (T). Like the regular dodecahedron, it has twelve identical pentagonal faces, with three meeting in each of the 20 vertices. However, the pentagons are not regular and the figure has no fivefold symmetry axes.
Although regular dodecahedra do not exist in crystals, the tetartoid form does. The name tetartoid comes from the Greek root for one-fourth because it has one fourth of full octahedral symmetry, and half of pyritohedral symmetry. The mineral cobaltite can have this symmetry form.
Abstractions sharing the solid's topology and symmetry can be created from the cube and the tetrahedron. In the cube each face is bisected by a slanted edge. In the tetrahedron each edge is trisected, and each of the new vertices connected to a face center. (In Conway polyhedron notation this is a gyro tetrahedron.)
The following points are vertices of a tetartoid pentagon under tetrahedral symmetry:
under the following conditions:
The regular dodecahedron is a tetartoid with more than the required symmetry. The triakis tetrahedron is a degenerate case with 12 zero-length edges. (In terms of the colors used above this means, that the white vertices and green edges are absorbed by the green vertices.)
A lower symmetry form of the regular dodecahedron can be constructed as the dual of a polyhedron constructed from two triangular anticupola connected base-to-base, called a triangular gyrobianticupola. It has D3d symmetry, order 12. It has 2 sets of 3 identical pentagons on the top and bottom, connected 6 pentagons around the sides which alternate upwards and downwards. This form has a hexagonal cross-section and identical copies can be connected as a partial hexagonal honeycomb, but all vertices will not match.
The rhombic dodecahedron is a zonohedron with twelve rhombic faces and octahedral symmetry. It is dual to the quasiregular cuboctahedron (an Archimedean solid) and occurs in nature as a crystal form. The rhombic dodecahedron packs together to fill space.
The rhombic dodecahedron can be seen as a degenerate pyritohedron where the 6 special edges have been reduced to zero length, reducing the pentagons into rhombic faces.
The rhombic dodecahedron has several stellations, the first of which is also a parallelohedral spacefiller.
Another important rhombic dodecahedron, the Bilinski dodecahedron, has twelve faces congruent to those of the rhombic triacontahedron, i.e. the diagonals are in the ratio of the golden ratio. It is also a zonohedron and was described by Bilinski in 1960. This figure is another spacefiller, and can also occur in non-periodic spacefillings along with the rhombic triacontahedron, the rhombic icosahedron and rhombic hexahedra.
There are 6,384,634 topologically distinct convex dodecahedra, excluding mirror images—the number of vertices ranges from 8 to 20. (Two polyhedra are "topologically distinct" if they have intrinsically different arrangements of faces and vertices, such that it is impossible to distort one into the other simply by changing the lengths of edges or the angles between edges or faces.)
Topologically distinct dodecahedra (excluding pentagonal and rhombic forms)
Armand Spitz used a dodecahedron as the "globe" equivalent for his Digital Dome planetarium projector, based upon a suggestion from Albert Einstein. | [
{
"paragraph_id": 0,
"text": "In geometry, a dodecahedron (from Ancient Greek δωδεκάεδρον (dōdekáedron); from δώδεκα (dṓdeka) 'twelve', and ἕδρα (hédra) 'base, seat, face') or duodecahedron is any polyhedron with twelve flat faces. The most familiar dodecahedron is the regular dodecahedron with regular pentagons as faces, which is a Platonic solid. There are also three regular star dodecahedra, which are constructed as stellations of the convex form. All of these have icosahedral symmetry, order 120.",
"title": ""
},
{
"paragraph_id": 1,
"text": "Some dodecahedra have the same combinatorial structure as the regular dodecahedron (in terms of the graph formed by its vertices and edges), but their pentagonal faces are not regular: The pyritohedron, a common crystal form in pyrite, has pyritohedral symmetry, while the tetartoid has tetrahedral symmetry.",
"title": ""
},
{
"paragraph_id": 2,
"text": "The rhombic dodecahedron can be seen as a limiting case of the pyritohedron, and it has octahedral symmetry. The elongated dodecahedron and trapezo-rhombic dodecahedron variations, along with the rhombic dodecahedra, are space-filling. There are numerous other dodecahedra.",
"title": ""
},
{
"paragraph_id": 3,
"text": "While the regular dodecahedron shares many features with other Platonic solids, one unique property of it is that one can start at a corner of the surface and draw an infinite number of straight lines across the figure that return to the original point without crossing over any other corner.",
"title": ""
},
{
"paragraph_id": 4,
"text": "The convex regular dodecahedron is one of the five regular Platonic solids and can be represented by its Schläfli symbol {5, 3}.",
"title": "Regular dodecahedron"
},
{
"paragraph_id": 5,
"text": "The dual polyhedron is the regular icosahedron {3, 5}, having five equilateral triangles around each vertex.",
"title": "Regular dodecahedron"
},
{
"paragraph_id": 6,
"text": "The convex regular dodecahedron also has three stellations, all of which are regular star dodecahedra. They form three of the four Kepler–Poinsot polyhedra. They are the small stellated dodecahedron {5/2, 5}, the great dodecahedron {5, 5/2}, and the great stellated dodecahedron {5/2, 3}. The small stellated dodecahedron and great dodecahedron are dual to each other; the great stellated dodecahedron is dual to the great icosahedron {3, 5/2}. All of these regular star dodecahedra have regular pentagonal or pentagrammic faces. The convex regular dodecahedron and great stellated dodecahedron are different realisations of the same abstract regular polyhedron; the small stellated dodecahedron and great dodecahedron are different realisations of another abstract regular polyhedron.",
"title": "Regular dodecahedron"
},
{
"paragraph_id": 7,
"text": "In crystallography, two important dodecahedra can occur as crystal forms in some symmetry classes of the cubic crystal system that are topologically equivalent to the regular dodecahedron but less symmetrical: the pyritohedron with pyritohedral symmetry, and the tetartoid with tetrahedral symmetry:",
"title": "Other pentagonal dodecahedra"
},
{
"paragraph_id": 8,
"text": "A pyritohedron is a dodecahedron with pyritohedral (Th) symmetry. Like the regular dodecahedron, it has twelve identical pentagonal faces, with three meeting in each of the 20 vertices (see figure). However, the pentagons are not constrained to be regular, and the underlying atomic arrangement has no true fivefold symmetry axis. Its 30 edges are divided into two sets – containing 24 and 6 edges of the same length. The only axes of rotational symmetry are three mutually perpendicular twofold axes and four threefold axes.",
"title": "Other pentagonal dodecahedra"
},
{
"paragraph_id": 9,
"text": "Although regular dodecahedra do not exist in crystals, the pyritohedron form occurs in the crystals of the mineral pyrite, and it may be an inspiration for the discovery of the regular Platonic solid form. The true regular dodecahedron can occur as a shape for quasicrystals (such as holmium–magnesium–zinc quasicrystal) with icosahedral symmetry, which includes true fivefold rotation axes.",
"title": "Other pentagonal dodecahedra"
},
{
"paragraph_id": 10,
"text": "The name crystal pyrite comes from one of the two common crystal habits shown by pyrite (the other one being the cube). In pyritohedral pyrite, the faces have a Miller index of (210), which means that the dihedral angle is 2·arctan(2) ≈ 126.87° and each pentagonal face has one angle of approximately 121.6° in between two angles of approximately 106.6° and opposite two angles of approximately 102.6°. The following formulas show the measurements for the face of a perfect crystal (which is rarely found in nature).",
"title": "Other pentagonal dodecahedra"
},
{
"paragraph_id": 11,
"text": "Height = 5 2 ⋅ Long side {\\displaystyle {\\text{Height}}={\\frac {\\sqrt {5}}{2}}\\cdot {\\text{Long side}}}",
"title": "Other pentagonal dodecahedra"
},
{
"paragraph_id": 12,
"text": "Width = 4 3 ⋅ Long side {\\displaystyle {\\text{Width}}={\\frac {4}{3}}\\cdot {\\text{Long side}}}",
"title": "Other pentagonal dodecahedra"
},
{
"paragraph_id": 13,
"text": "Short sides = 7 12 ⋅ Long side {\\displaystyle {\\text{Short sides}}={\\sqrt {\\frac {7}{12}}}\\cdot {\\text{Long side}}}",
"title": "Other pentagonal dodecahedra"
},
{
"paragraph_id": 14,
"text": "The eight vertices of a cube have the coordinates (±1, ±1, ±1).",
"title": "Other pentagonal dodecahedra"
},
{
"paragraph_id": 15,
"text": "The coordinates of the 12 additional vertices are (0, ±(1 + h), ±(1 − h)), (±(1 + h), ±(1 − h), 0) and (±(1 − h), 0, ±(1 + h)).",
"title": "Other pentagonal dodecahedra"
},
{
"paragraph_id": 16,
"text": "h is the height of the wedge-shaped \"roof\" above the faces of that cube with edge length 2.",
"title": "Other pentagonal dodecahedra"
},
{
"paragraph_id": 17,
"text": "An important case is h = 1/2 (a quarter of the cube edge length) for perfect natural pyrite (also the pyritohedron in the Weaire–Phelan structure).",
"title": "Other pentagonal dodecahedra"
},
{
"paragraph_id": 18,
"text": "Another one is h = 1/φ = 0.618... for the regular dodecahedron. See section Geometric freedom for other cases.",
"title": "Other pentagonal dodecahedra"
},
{
"paragraph_id": 19,
"text": "Two pyritohedra with swapped nonzero coordinates are in dual positions to each other like the dodecahedra in the compound of two dodecahedra.",
"title": "Other pentagonal dodecahedra"
},
{
"paragraph_id": 20,
"text": "The pyritohedron has a geometric degree of freedom with limiting cases of a cubic convex hull at one limit of collinear edges, and a rhombic dodecahedron as the other limit as 6 edges are degenerated to length zero. The regular dodecahedron represents a special intermediate case where all edges and angles are equal.",
"title": "Other pentagonal dodecahedra"
},
{
"paragraph_id": 21,
"text": "It is possible to go past these limiting cases, creating concave or nonconvex pyritohedra. The endo-dodecahedron is concave and equilateral; it can tessellate space with the convex regular dodecahedron. Continuing from there in that direction, we pass through a degenerate case where twelve vertices coincide in the centre, and on to the regular great stellated dodecahedron where all edges and angles are equal again, and the faces have been distorted into regular pentagrams. On the other side, past the rhombic dodecahedron, we get a nonconvex equilateral dodecahedron with fish-shaped self-intersecting equilateral pentagonal faces.",
"title": "Other pentagonal dodecahedra"
},
{
"paragraph_id": 22,
"text": "A tetartoid (also tetragonal pentagonal dodecahedron, pentagon-tritetrahedron, and tetrahedric pentagon dodecahedron) is a dodecahedron with chiral tetrahedral symmetry (T). Like the regular dodecahedron, it has twelve identical pentagonal faces, with three meeting in each of the 20 vertices. However, the pentagons are not regular and the figure has no fivefold symmetry axes.",
"title": "Other pentagonal dodecahedra"
},
{
"paragraph_id": 23,
"text": "Although regular dodecahedra do not exist in crystals, the tetartoid form does. The name tetartoid comes from the Greek root for one-fourth because it has one fourth of full octahedral symmetry, and half of pyritohedral symmetry. The mineral cobaltite can have this symmetry form.",
"title": "Other pentagonal dodecahedra"
},
{
"paragraph_id": 24,
"text": "Abstractions sharing the solid's topology and symmetry can be created from the cube and the tetrahedron. In the cube each face is bisected by a slanted edge. In the tetrahedron each edge is trisected, and each of the new vertices connected to a face center. (In Conway polyhedron notation this is a gyro tetrahedron.)",
"title": "Other pentagonal dodecahedra"
},
{
"paragraph_id": 25,
"text": "The following points are vertices of a tetartoid pentagon under tetrahedral symmetry:",
"title": "Other pentagonal dodecahedra"
},
{
"paragraph_id": 26,
"text": "under the following conditions:",
"title": "Other pentagonal dodecahedra"
},
{
"paragraph_id": 27,
"text": "The regular dodecahedron is a tetartoid with more than the required symmetry. The triakis tetrahedron is a degenerate case with 12 zero-length edges. (In terms of the colors used above this means, that the white vertices and green edges are absorbed by the green vertices.)",
"title": "Other pentagonal dodecahedra"
},
{
"paragraph_id": 28,
"text": "A lower symmetry form of the regular dodecahedron can be constructed as the dual of a polyhedron constructed from two triangular anticupola connected base-to-base, called a triangular gyrobianticupola. It has D3d symmetry, order 12. It has 2 sets of 3 identical pentagons on the top and bottom, connected 6 pentagons around the sides which alternate upwards and downwards. This form has a hexagonal cross-section and identical copies can be connected as a partial hexagonal honeycomb, but all vertices will not match.",
"title": "Other pentagonal dodecahedra"
},
{
"paragraph_id": 29,
"text": "The rhombic dodecahedron is a zonohedron with twelve rhombic faces and octahedral symmetry. It is dual to the quasiregular cuboctahedron (an Archimedean solid) and occurs in nature as a crystal form. The rhombic dodecahedron packs together to fill space.",
"title": "Rhombic dodecahedron"
},
{
"paragraph_id": 30,
"text": "The rhombic dodecahedron can be seen as a degenerate pyritohedron where the 6 special edges have been reduced to zero length, reducing the pentagons into rhombic faces.",
"title": "Rhombic dodecahedron"
},
{
"paragraph_id": 31,
"text": "The rhombic dodecahedron has several stellations, the first of which is also a parallelohedral spacefiller.",
"title": "Rhombic dodecahedron"
},
{
"paragraph_id": 32,
"text": "Another important rhombic dodecahedron, the Bilinski dodecahedron, has twelve faces congruent to those of the rhombic triacontahedron, i.e. the diagonals are in the ratio of the golden ratio. It is also a zonohedron and was described by Bilinski in 1960. This figure is another spacefiller, and can also occur in non-periodic spacefillings along with the rhombic triacontahedron, the rhombic icosahedron and rhombic hexahedra.",
"title": "Rhombic dodecahedron"
},
{
"paragraph_id": 33,
"text": "There are 6,384,634 topologically distinct convex dodecahedra, excluding mirror images—the number of vertices ranges from 8 to 20. (Two polyhedra are \"topologically distinct\" if they have intrinsically different arrangements of faces and vertices, such that it is impossible to distort one into the other simply by changing the lengths of edges or the angles between edges or faces.)",
"title": "Other dodecahedra"
},
{
"paragraph_id": 34,
"text": "Topologically distinct dodecahedra (excluding pentagonal and rhombic forms)",
"title": "Other dodecahedra"
},
{
"paragraph_id": 35,
"text": "Armand Spitz used a dodecahedron as the \"globe\" equivalent for his Digital Dome planetarium projector, based upon a suggestion from Albert Einstein.",
"title": "Practical usage"
}
] | In geometry, a dodecahedron or duodecahedron is any polyhedron with twelve flat faces. The most familiar dodecahedron is the regular dodecahedron with regular pentagons as faces, which is a Platonic solid. There are also three regular star dodecahedra, which are constructed as stellations of the convex form. All of these have icosahedral symmetry, order 120. Some dodecahedra have the same combinatorial structure as the regular dodecahedron, but their pentagonal faces are not regular:
The pyritohedron, a common crystal form in pyrite, has pyritohedral symmetry, while the tetartoid has tetrahedral symmetry. The rhombic dodecahedron can be seen as a limiting case of the pyritohedron, and it has octahedral symmetry. The elongated dodecahedron and trapezo-rhombic dodecahedron variations, along with the rhombic dodecahedra, are space-filling. There are numerous other dodecahedra. While the regular dodecahedron shares many features with other Platonic solids, one unique property of it is that one can start at a corner of the surface and draw an infinite number of straight lines across the figure that return to the original point without crossing over any other corner. | 2001-09-07T17:58:24Z | 2023-12-26T00:35:11Z | [
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8,408 | Darwin, Northern Territory | Darwin (/ˈdɑːrwɪn/ DAR-win; Larrakia: Garramilla) is the capital city of the Northern Territory, Australia. With a population of 139,902 at the 2021 census, the city contains most of the sparsely populated Northern Territory's residents. It is the smallest, wettest, and most northerly of the Australian capital cities and serves as the Top End's regional centre.
Darwin's proximity to Southeast Asia makes it a key link between Australia and countries such as Indonesia and East Timor. The Stuart Highway begins in Darwin and extends southerly across central Australia through Tennant Creek and Alice Springs, concluding in Port Augusta, South Australia. The city is built upon a low bluff overlooking Darwin Harbour. Darwin's suburbs begin at Lee Point in the north and stretch to Berrimah in the east. The Stuart Highway extends to Darwin's eastern satellite city of Palmerston and its suburbs.
The Darwin region, like much of the Top End, has a tropical climate, with a wet and dry season. A period known locally as "the build up" leading up to Darwin's wet season sees temperature and humidity increase. Darwin's wet season typically arrives in late November to early December and brings with it heavy monsoonal downpours, spectacular lightning displays, and increased cyclone activity. During the dry season, the city has clear skies and mild sea breezes from the harbour.
The Larrakia people are the traditional owners of the Darwin area and Aboriginal people are a significant proportion of the population. On 9 September 1839, HMS Beagle sailed into Darwin Harbour during its survey of the area. John Clements Wickham named the region "Port Darwin" in honour of their former shipmate Charles Darwin, who had sailed with them on the ship's previous voyage. The settlement there became the town of Palmerston in 1869, but was renamed Darwin in 1911. The city has been almost entirely rebuilt four times, following devastation caused by a cyclone in 1897, another one in 1937, Japanese air raids during World War II, and Cyclone Tracy in 1974.
The Aboriginal people of the Larrakia language group are the traditional custodians and earliest known inhabitants of the greater Darwin area. Their name for the area is Garramilla, pronounced /ɡɑːrəmɪlə/ and meaning "white stone", referring to the colour of rock and sea cliffs found in the area. They had trading routes with Southeast Asia (see Macassan contact with Australia) and imported goods from as far afield as South and Western Australia. Established songlines penetrated throughout the country, allowing stories and histories to be told and retold along the routes. The extent of shared songlines and history of multiple clan groups within this area is contestable.
The Dutch visited Australia's northern coastline in the 1600s and landed on the Tiwi Islands only to be repelled by the Tiwi peoples. The Dutch created the first European maps of the area. This accounts for the Dutch names in the area, such as Arnhem Land and Groote Eylandt. During this period, Dutch explorers named the region around Darwin—sometimes including nearby Kimberley—variations of "Van Diemen's Land", after the VOC governor-general Anthony van Diemen. This should not be confused with the more general and prolonged use of the same name for Tasmania.
The first British person to see Darwin harbour appears to have been Lieutenant John Lort Stokes of HMS Beagle on 9 September 1839. The ship's captain, Commander John Clements Wickham, named the port after Charles Darwin, the British naturalist who had sailed with him when he served as first lieutenant on the earlier second expedition of the Beagle.
In 1863, the Northern Territory was transferred from New South Wales to South Australia. In 1864 South Australia sent B. T. Finniss north as Government Resident to survey and found a capital for its new territory. Finniss chose a site at Escape Cliffs, near the entrance to Adelaide River, about 60 kilometres (37 mi) northeast of the modern city. This attempt was short-lived, and the settlement abandoned by 1865. On 5 February 1869, George Goyder, the Surveyor-General of South Australia, established a small settlement of 135 people at Port Darwin between Fort Hill and the escarpment. Goyder named the settlement Palmerston after British Prime Minister Lord Palmerston. In 1870, the first poles for the Overland Telegraph were erected in Darwin, connecting Australia to the rest of the world. The discovery of gold by employees of the Australian Overland Telegraph Line digging holes for telegraph poles at Pine Creek in the 1880s spawned a gold rush, which further boosted the colony's development.
In February 1872 the brigantine Alexandra was the first private vessel to sail from an English port directly to Darwin, carrying people many of whom were coming to recent gold finds.
In early 1875 Darwin's white population had grown to approximately 300 because of the gold rush. On 17 February 1875 the SS Gothenburg left Darwin en route for Adelaide. The approximately 88 passengers and 34 crew (surviving records vary) included government officials, circuit-court judges, Darwin residents taking their first furlough, and miners. While travelling south along the north Queensland coast, the Gothenburg encountered a cyclone-strength storm and was wrecked on a section of the Great Barrier Reef. Only 22 men survived, while between 98 and 112 people perished. Many passengers who perished were Darwin residents, and news of the tragedy severely affected the small community, which reportedly took several years to recover.
In the 1870s, relatively large numbers of Chinese settled at least temporarily in the Northern Territory; many were contracted to work the goldfields and later to build the Palmerston to Pine Creek railway. By 1888 there were 6,122 Chinese in the Northern Territory, mostly in or around Darwin. The early Chinese settlers were mainly from Guangdong Province. The Chinese community established Darwin Chinatown. At the end of the 19th century, anti-Chinese feelings grew in response to the 1890s economic depression, and the White Australia policy meant many Chinese left the territory. But some stayed, became British subjects, and established a commercial base in Darwin.
The Northern Territory was initially settled and administered by South Australia, until its transfer to the Commonwealth in 1911. In the same year, the city's official name changed from Palmerston to Darwin.
The period between 1911 and 1919 was filled with political turmoil, particularly with trade union unrest, which culminated on 17 December 1918. Led by Harold Nelson, some 1,000 demonstrators marched to Government House at Liberty Square in Darwin, where they burnt an effigy of the Administrator of the Northern Territory, John Gilruth, and demanded his resignation. The incident became known as the Darwin Rebellion. Their grievances were against the two main Northern Territory employers: Vestey's Meatworks and the federal government. Both Gilruth and the Vestey company left Darwin soon afterward.
On 18 October 1918, during the Spanish flu pandemic, the SS Mataram sailing from Singapore with infectious diseases arrived in Darwin.
In 1931, the 17 remaining patients from the leprosarium at Cossack, Western Australia were moved to Darwin, after it closed down. It was at a time when many Aboriginal people who were thought to have leprosy or other infectious diseases were sent to lock hospitals and leprosariums under the Aborigines Act 1905, which gave the Chief Protector of Aborigines powers to arrest and send any Indigenous person suspected of having a range of diseases to one of these institutions.
Around 10,000 Australian and other Allied troops arrived in Darwin at the outset of World War II to defend Australia's northern coast. On 19 February 1942 at 0957, 188 Japanese warplanes attacked Darwin in two waves. It was the same fleet that had bombed Pearl Harbor, though considerably more bombs were dropped on Darwin than on Pearl Harbor. The attack killed at least 243 people and caused immense damage to the town, airfields, and aircraft. These were by far the most serious attacks on Australia in time of war, in terms of fatalities and damage. They were the first of many raids on Darwin.
Darwin Chinatown which lay within the heart of Darwin was razed to the ground by the Japanese bombing and was never rebuilt. Northern Territory administrator Aubrey Abbott wanted to eliminate the Chinese community and forcibly seized their land as it was considered prime real estate.
Darwin was further developed after the war, with sealed roads constructed connecting the region to Alice Springs to the south and Mount Isa to the southeast, and Manton Dam built in the south to provide the city with water. On Australia Day (26 January) 1959, Darwin was granted city status.
On 25 December 1974, Darwin was struck by Cyclone Tracy, which killed 71 people and destroyed over 70% of the city's buildings, including many old stone buildings such as the Palmerston Town Hall, which could not withstand the lateral forces the winds generated. After the disaster, 30,000 of the population of 46,000 were evacuated in the biggest airlift in Australia's history. The town was rebuilt with newer materials and techniques during the late 1970s by the Darwin Reconstruction Commission, led by former Brisbane Lord mayor Clem Jones. A satellite city of Palmerston was built 20 km (12 mi) east of Darwin in the early 1980s.
On 17 September 2003, the Adelaide–Darwin railway was completed, with the opening of the Alice Springs–Darwin standard gauge line.
Darwin hosted many of aviation's early pioneers. On 10 December 1919, Captain Ross Smith and his crew landed in Darwin and won a £10,000 prize from the Australian government for completing the first flight from London to Australia in under 30 days. Smith and his crew flew a Vickers Vimy, G-EAOU, and landed on an airstrip that has become Ross Smith Avenue.
Other aviation pioneers include Amy Johnson, Amelia Earhart, Sir Charles Kingsford Smith and Bert Hinkler. The original QANTAS Empire Airways Ltd Hangar, a registered heritage site, was part of the original Darwin Civil Aerodrome in Parap and is now a museum that still bears scars from the bombing of Darwin during World War II.
Darwin was home to Australian and U.S. pilots during the war, with airstrips built in and around Darwin. Today Darwin provides a staging ground for military exercises.
Darwin was a compulsory stopover and checkpoint in the London-to-Melbourne Centenary Air Race in 1934. The official name of the race was the MacRobertson Air Race. Winners of the race were Tom Campbell Black and C. W. A. Scott.
The following is an excerpt from Time magazine, 29 October 1934:
Third Day. Biggest sensation of the race came just before dawn on the third day, when burly Lieutenant Scott and dapper Captain Black flew their scarlet Comet into Darwin. They had covered the last 300 miles [480 km] over water on one motor, risked death landing on a field made soggy by the first rain in seven months. Said sandy-haired Lieutenant Scott: "We've had a devil of a trip." But they had flown 9000 miles [14000 km] in two days, had broken the England to Australia record of 162 hr. in the unbelievable time of 52hr. 33 min., were only 2000 miles [3200 km] from their goal at Melbourne.
The Australian Aviation Heritage Centre is about 8 km (5 mi) from the city centre on the Stuart Highway and is one of only three places outside the United States where a B-52 bomber (on permanent loan from the United States Air Force) is on public display.
Darwin is a coastal city, situated along the western shoreline of the Northern Territory. The water meets the land from the Beagle Gulf, which extends out into the Timor Sea. The central business district occupies a low bluff overlooking Darwin Harbour to the south, beyond which lie East Arm, Middle Arm, Northern Territory, and, across the gulf, West Arm. Middle Arm has an industrial precinct on the peninsula, which is being promoted as a sustainable development area that will include plants for industries such as low-emission petrochemicals, renewable hydrogen, and carbon capture storage. The city is flanked by Frances Bay to the east and Cullen Bay to the west.
The rest of the city is relatively flat and low-lying, and areas bordering the coast are home to recreational reserves, extensive beaches, and excellent fishing.
Darwin and its suburbs spread in an approximately triangular shape, with the older southwestern suburbs—and the city itself—forming one corner, the newer northern suburbs another, and the eastern suburbs, progressing towards Palmerston, forming the third.
The older part of Darwin is separated from the newer northern suburbs by Darwin International Airport and RAAF Base Darwin. Palmerston is a satellite city 20 km (12 mi) east of Darwin that was established in the 1980s and is one of Australia's fastest-growing municipalities. Darwin's rural areas, including Howard Springs, Humpty Doo and Berry Springs, are experiencing strong growth.
Darwin's central business district (CBD) is bounded by Daly Street in the northwest, McMinn Street in the northeast, Mitchell Street on the southwest, and Bennett Street on the southeast. The CBD has been the focus of a number of major projects, such as the billion-dollar redevelopment of the Stokes Hill wharf waterfront area, including a convention centre with seating for 1,500 people and approximately 4,000 square metres (43,000 sq ft) of exhibition space. The developers announced that this includes hotels, residential apartments, and public space. The city's main industrial areas are along the Stuart Highway toward Palmerston, centred on Winnellie. The area'a largest shopping precinct is Casuarina Square.
The most expensive residential areas stand along the coast in suburbs such as the marina of Cullen Bay, Larrakeyah, Bayview and Brinkin. These low-lying regions are at risk during cyclones and higher tides, but adequate drainage and stringent building regulations have reduced the potential damage to buildings or injury to residents. The inner northern suburbs are home to lower-income households, although low-income Territory Housing units are scattered throughout the metropolitan area. The suburb of Lyons was part of a multi-stage land release and development in the Northern Suburbs; planning, development and construction took place from 2004 to 2009. More recent developments near Lyons subdivision includes the suburb of Muirhead.
Darwin has a tropical savanna climate (Köppen Aw) with distinct wet and dry seasons, and the average maximum temperature is similar year round. The Australian Building Codes Board classifies it as Climate Zone 1 based on its very humid summers and warm winters. The dry season runs from about May to September, during which nearly every day is sunny, and afternoon relative humidity averages around 30%.
The driest period of the year, seeing about 5 mm (0.20 in) of monthly rainfall on average, is between May and September. In the coolest months, June and July, the daily minimum temperature may dip as low as 14 °C (57 °F), but very rarely lower, and a temperature lower than 10 °C (50 °F) has never been recorded in the city centre. Outer suburbs away from the coast occasionally record temperatures as low as 5 °C (41 °F) in the dry season. For a 147‑day period during the 2012 dry season, from 5 May to 29 September, Darwin recorded no precipitation. Prolonged periods of no precipitation are common in the dry season in Northern Australia (particularly in the Northern Territory and northern regions of Western Australia), although a no-rainfall event of this extent is rare. The 3pm dewpoint average in the wet season is around 24.0 °C (75.2 °F).
Extreme temperatures at the Darwin Post Office Station have ranged from 40.4 °C (104.7 °F) on 17 October 1892 to 13.4 °C (56.1 °F) on 25 June 1891; extreme temperatures at the Darwin Airport station (which is farther from the coast and routinely records cooler temperatures than the post office station, which is in Darwin's CBD) have ranged from 38.9 °C (102.0 °F) on 18 October 1982 to 10.4 °C (50.7 °F) on 29 July 1942. The highest minimum temperature on record is 30.7 °C (87.3 °F) on 18 January 1928 for the post office station and 29.7 °C (85.5 °F) on both 25 November 1987 and 17 December 2014 for the airport station. The lowest maximum temperature on record is 18.4 °C (65.1 °F) on 3 June 1904 for the post office station and 21.1 °C (70.0 °F) on 14 July 1968 for the airport station.
The wet season is associated with tropical cyclones and monsoon rains. Most rainfall occurs between December and March (the summer), when thunderstorms are common and afternoon relative humidity averages over 70 percent during the wettest months. It does not rain every day during the wet season, but most days have plentiful cloud cover; January averages under six hours of bright sunshine daily. Darwin's highest daily rainfall verified by the Bureau of Meteorology is 367.6 millimetres (14.47 in), which fell when Cyclone Carlos bore down on the Darwin area on 16 February 2011. February 2011 was also Darwin's wettest month ever recorded, with 1,110.2 millimetres (43.71 in) at the airport.
The hottest months are October and November, just before the onset of the main rain season. The temperature is usually below 35 °C (95 °F), but the heat index sometimes rises above 45 °C (113 °F), because of humidity levels that most find uncomfortable. Because of its long dry season, Darwin has the second-highest average daily hours of sunshine (8.4) of any Australian capital, with the most sunshine from April to November; only Perth, Western Australia, averages more (8.8). The sun passes directly overhead in mid-October and mid-February.
The average temperature of the sea ranges from 25.8 °C (78.4 °F) in July to 31.5 °C (88.7 °F) in December.
Darwin occupies one of the most lightning-prone areas in Australia. On 31 January 2002 an early-morning squall line produced over 5,000 cloud-to-ground lightning strikes within a 60-kilometre (37 mi) radius of Darwin alone—about three times the amount of lightning that Perth experiences on average in an entire year.
Darwin's population changed after the Second World War. Like many other Australian cities, Darwin experienced influxes from Europe, with significant numbers of Italians and Greeks during the 1960s and 1970s. It also began to experience an influx from other European countries, which included the Dutch, Germans, and many others. A significant proportion of Darwin's residents are recent immigrants from Asia, including the peoples of East Timor.
At the 2016 census, the most commonly nominated ancestries were:
38.3% of the population at the 2016 census was born overseas. The five largest groups of overseas-born were from the Philippines (3.6%), England (3.1%), New Zealand (2.1%), India (2%) and Greece (0.9%).
8.7% of the population, or 11,960 people, identified as Indigenous Australians (Aboriginal Australians and/or Torres Strait Islanders) in 2016. This is the largest proportion of any Australian capital city.
At the 2016 census, 58% of the population spoke only English at home. Other languages spoken at home include Tagalog (3.7%), Greek (3.5%), Mandarin (2.0%), Nepali (1.2%), Indonesian (1.0%), Australian Aboriginal languages (1.0%), Malayalam (0.9%), Vietnamese (0.8%), Cantonese (0.7%), Italian (0.6%), Portuguese (0.5%, mostly spoken by Timorese), and Tamil (0.5%).
In 2011, the Darwin population averaged 33 years old (compared to the national average of around 37), to a large extent because of the military presence and because many people opt to retire elsewhere.
As of 2008, Christianity had the most adherents in Darwin, with 56,613 followers accounting for 49.5 percent of the population. The largest denominations of Christianity are Roman Catholicism (24,538 or 21.5 percent), Anglicanism (14,028 or 12.3 percent) and Greek Orthodoxy (2,964 or 2.6 percent). Buddhists, Muslims, Hindus and Jews account for 3.2 percent of Darwin's population. There were 26,695 or 23.3 percent of people professing no religion.
The Darwin City Council (incorporated under the Northern Territory Local Government Act 1993) governs the City of Darwin, which takes in the CBD and the suburbs. The city has been governed by a city council form of government since 1957. The council consists of 13 elected members, the lord mayor, and 12 aldermen.
The City of Darwin electorate is organised into four electoral units or wards. The wards are Chan, Lyons, Richardson, and Waters. The constituents of each ward are directly responsible for electing three aldermen. Constituents of all wards are directly responsible for electing the Lord Mayor of Darwin. Since the August 2017 council elections, the mayor has been Kon Vatskalis.
The rest of the Darwin area is divided into two local government areas—the Palmerston City Council and the Shire of Coomalie. These areas have elected councils that are responsible for functions delegated to them by the Northern Territory Government, such as planning and garbage collection.
The Legislative Assembly of the Northern Territory convenes in Darwin in the Northern Territory Parliament House. Government House, the official residence of the Administrator of the Northern Territory, is on the Esplanade.
Darwin is split between nine electoral divisions in the Legislative Assembly—Port Darwin, Fannie Bay, Fong Lim, Nightcliff, Sanderson, Johnston, Casuarina, Wanguri, and Karama. Historically, Darwin voters elected Country Liberal Party members, but since the turn of the 21st century, voters have often selected Labor members, particularly in the more diverse northern section; as of the 2020 Northern Territory general election, all of Darwin's nine Legislative Assembly electoral divisions are held by Labor, with Labor also holding both the Northern Territory's federal electorates, Solomon and Lingiari.
Also on the Esplanade is the Supreme Court of the Northern Territory. Darwin has a Magistrate's Court is on the corner of Cavenagh and Bennett streets, quite close to the Darwin City Council Chambers.
Darwin's police force are members of the Northern Territory Police, under the NT Police Darwin Metropolitan Command. The Darwin urban centre includes Darwin City and the associated suburbs from Buffalo Creek, Berrimah, and East Arm westwards, representing around 35% of the Northern Territory's population. Palmerston urban centre closely approximates the Palmerston Local Government Area, and represents approximately 13% of the Northern Territory's population.
Darwin has had a history of alcohol abuse and violent crime, with 6,000 assaults in 2009, of which 350 resulted in broken jaws and noses—more than anywhere else in the world, according to the Royal Darwin Hospital.
Mitchell Street, with its numerous pubs, clubs and other entertainment venues, was one of the areas policed by the CitySafe Unit, officially launched by the NT Chief Minister Paul Henderson on 25 February 2009. It was credited with success in tackling alcohol abuse linked to crime, and the NT police were looking at establishing a specialist licensing enforcement unit in 2010.
The First Response Patrol, run by Larrakia Nation, which helps move homeless Indigenous women out of dangerous situations, was credited with the decline in sexual assaults in 2009. The service operates every day from 5am to 2am.
In the 10 months between 1 October 2018, the date that the alcohol floor price and various other measures were imposed by the NT government following the Riley Review, and 31 July 2019, alcohol-related assaults dropped by 16% and domestic violence by 9% in the Darwin area.
The rate of offending in most categories of crime dropped in the Darwin urban area between 2018 and 2019, with the notable exceptions of motor vehicle theft and break-ins (both up about 12%). Apart from sexual assault, which rose from 21 to 46, all other categories of crime declined in Palmerston.
The two largest economic sectors are mining and tourism. Given its location, Darwin serves as a gateway for Australian travellers to Asia.
Mining and energy industry production exceeds $2.5 billion per annum. The most important mineral resources are gold, zinc, and bauxite, along with manganese and many others. The energy production is mostly off-shore with oil and natural gas from the Timor Sea, although there are significant uranium deposits near Darwin. Tourism employs 8% of Darwin residents and is expected to grow as domestic and international tourists now spend time in Darwin during the wet and dry seasons. Federal spending is also a major contributor to the local economy. Darwin's importance as a port is expected to grow, due to the increased exploitation of petroleum in the nearby Timor Sea and to the completion of the railway link and continued expansion in trade with Asia. During 2005, a number of major construction projects started in Darwin. One is the redevelopment of the Wharf Precinct, which includes a large convention and exhibition centre, apartment housing including Outrigger Pandanas and Evolution on Gardiner, retail and entertainment outlets including a large wave pool and safe swimming lagoon. The Chinatown project has also started with plans to construct Chinese-themed retail and dining outlets.
Tourism is one of Darwin's largest industries and a major employment sector for the Northern Territory. In 2005–2006, 1.38 million people visited the Northern Territory. They stayed for 9.2 million nights and spent over $1.5 billion. The tourism industry directly employed 8,391 Territorians in June 2006, and, when indirect employment is included, tourism typically accounts for more than 14,000 jobs across the Territory.
Darwin is a hub for tours to Kakadu National Park, Litchfield National Park and Katherine Gorge. The year is traditionally divided into the wet and dry seasons, but there are up to six traditional seasons in Darwin. It is warm and sunny from May to September. Humidity rises during the green season, from October to April, bringing thunderstorms and monsoonal rains that rejuvenate the landscape. Tourism is largely seasonal, with most tourists visiting during the cooler dry season, from April to September.
The military presence in both Darwin and the wider Northern Territory is a substantial source of employment. On 16 November 2011, Prime Minister Julia Gillard and President Barack Obama announced that the United States would station troops in Australia for the first time since World War II. The agreement between the U.S. and Australia would involve a contingent of 250 Marines arriving in Darwin in 2012, with the total number rising to a maximum of 2,500 troops by 2017 on six-month rotations as well as a supporting air element including F-22 Raptors, F-35 Joint Strike Fighters and KC-135 refuellers. China and Indonesia have expressed concern about the decision. Some analysts have argued that an expanded U.S. presence could pose a threat to security. Gillard announced that the first 200 U.S. Marines had arrived in Darwin from Hawaii on 3 April 2012. In 2013, further news of other expansion vectors aired in U.S. media, with no comment or confirmation from Australian authorities. The agreement between the two governments remains hidden from public scrutiny. Marine numbers based in Darwin increased to more than 1,150 by 2014. In a 2019 telephone survey of local residents, 51% of respondents had positive feelings about the U.S. troop presence, with 6% responding negatively. In late 2021, the U.S. Department of Defense signed a contract to create a 300 million litres (79,000,000 US gal) fuel storage facility at East Arm.
Darwin hosts biennial multi-nation exercises named "Pitch Black"; in 2014 this involved military personnel from Australia, New Zealand, Singapore, Thailand, United Arab Emirates, and the United States.
Education is overseen territory-wide by the Department of Education and Training (DET), whose role is to continually improve education outcomes for all students, with a focus on Indigenous students.
Darwin is served by a number of public and private schools that cater to local and overseas students. Over 16,500 primary and secondary students are enrolled in schools in Darwin, with 10,524 students attending primary education, and 5,932 students attending secondary education. Over 12,089 students are enrolled in government schools, and 2,124 in independent schools.
There were 9,764 students attending schools in the City of Darwin area. 6,045 students attended primary schools and 3,719 attended secondary schools. Over 7,161 students are enrolled in government schools and 1,108 in independent schools. There are over 35 primary and pre-schools and 12 secondary schools, including both government and non-government. Most schools in the city are secular, but there are a small number of Catholic and Lutheran institutions. Students intending to complete their secondary education work toward either the Northern Territory Certificate of Education, the Victorian Certificate of Education, or the Victorian Certificate of Applied Learning (the latter two are offered only at Haileybury Rendall School). Until the sale and restructuring of Kormilda College in 2018, it was the only school to offer the International Baccalaureate in the Northern Territory.
Schools have been restructured into Primary, Middle, and High schools since the beginning of 2007.
Darwin's largest university is Charles Darwin University, the Northern Territory's central provider of tertiary education. It has both vocational and academic courses, acting as both a university and an Institute of TAFE. More than 5,500 students are enrolled in tertiary and further education courses.
Darwin is also home to several private vocational colleges, including Alana Kaye College, which focuses on Early Childhood Education and Care, and Latitude College, which offers Commercial Cookery and Hospitality Management.
As Darwin was destroyed by cyclones several times and suffered severe bomb damage during World War II, few historic buildings remain in town. The Administrator's Office dating from 1883 was used as a law court and as a police station and was only slightly damaged by bombs, but in 1974, the cyclone completely destroyed it. In 1979, it was decided to rebuild, and the reconstruction was finished in 1981. The building houses government offices today. Opposite the building, Survivors Lookout offers a view of the marina.
In a park in the south of the CBD, the ruin of the Town Hall built in 1883 and destroyed by the cyclone in 1974 can be seen. Browns Mart is a stone building dating from 1880 opposite the park. Browns Mart was originally used in many different activities including commerce, storage, shipping and insurance agency, mining exchange and meetings of local organisations but it was transformed into a theatre.
One of Darwin's most prominent buildings is the Chinese Temple, which was founded in 1887 and damaged by cyclones in 1897 and in 1937. It was severely damaged by bombs in 1942 and rebuilt after the war. On 24 December 1974 the cyclone completely destroyed it. Reconstruction was completed in 1978.
There are various modern churches in Darwin. St Mary's Star of the Sea Roman Catholic Cathedral was inaugurated in 1962. Christ Church Anglican Cathedral was rebuilt in 1977 after being severely damaged by bombs in 1942 and destroyed by Cyclone Tracy in 1974. The Uniting Memorial Church was built in 1960.
The Darwin Symphony Orchestra was assembled in 1989 and has performed throughout the Territory. The Darwin Theatre Company is a locally produced professional theatre production company, performing locally and nationally.
The Darwin Entertainment Centre is the city's main concert venue and hosts theatre and orchestral performances. Other theatres include the Darwin Convention Centre, which opened in July 2008. The Darwin Convention Centre is part of the $1.1 billion Darwin Waterfront project.
The Northern Territory Museum and Art Gallery (MAGNT) in Darwin gives an overview of the history of the area, including exhibits on Cyclone Tracy and the boats of the Pacific Islands. The MAGNT also organises the annual Telstra National Aboriginal and Torres Strait Islander Art Award, the longest-running Indigenous art award in Australia. The MAGNT also manages the Defence of Darwin Experience, a multi-media installation that tells the story of the Japanese air raids on Darwin during World War II.
The NT Dance Company is led by choreographer Gary Lang, who has been artistic director since 2012. Lang previously taught at many leading dance companies, including Bangarra Dance Theatre, after studying dance at NAISDA in Sydney and working as a dancer for years. The company has a strong focus on culture, and also works with disadvantaged young Indigenous people.
Local and visiting bands can be heard at venues including the Darwin Entertainment Centre, The Vic Hotel, Happy Yess, and Brown's Mart. Artists such as Jessica Mauboy and The Groovesmiths call Darwin home.
The multiculturalism of Darwin has helped make Southeast Asian noodle broth laksa the city's favourite meal.
Weekly markets include the popular Mindil Beach Sunset Market (Thursdays and Sundays during the dry season); Parap Market; Nightcliff Market; and Rapid Creek market.
Darwin's only casino opened in 1979 as the Don Casino, operating out of the Don Hotel on Cavenagh Street. The present site of the hotel and casino on Darwin's Mindil Beach opened in 1983, at which point gambling operations ceased at the Don Hotel and resumed at the newly built facilities. The new hotel and casino was named Mindil Beach Casino until 1985, when the name changed to the Diamond Beach Hotel Casino. Upon its acquisition by MGM Grand the hotel was rebranded as the MGM Grand Darwin, before it changed to Skycity Darwin after Skycity Entertainment Group purchased the hotel in 2004.
Mitchell Street in the central business district is lined with nightclubs, takeaways, and restaurants. This is the city's entertainment hub. There are several smaller theatres, three cinema complexes (CBD, Casuarina, and Palmerston), and the Deckchair Cinema. An open-air cinema operates through the dry season, from April to October, screening independent and arthouse films.
During the months of October–May the sea contains deadly box jellyfish, known locally as stingers or sea wasps. Saltwater crocodiles are common in all waterways surrounding Darwin and are occasionally found in Darwin Harbour and on local beaches. An active trapping program is carried out by the NT Government to limit numbers of crocodiles within the Darwin urban waterway area.
The city has many kilometres of beaches, including the Casuarina Beach and renowned Mindil Beach, home of the Mindil Beach markets. Darwin City Council has designated an area of Casuarina Beach as a free beach, which has been designated as a nudist beach area since 1976.
Bundilla Beach was formerly named Vesteys Beach, as it was one of the beaches overlooked by Vestey's Meatworks, which existed from 1914 to 1920 and was involved in the Darwin rebellion. In March 2021, the beach was formally renamed Bundilla Beach, the name by which it had long been known to the traditional owners, the Larrakia people.
The Darwin Surf Life Saving Club operates longboats and surf skis and provides events and lifesaving accreditations.
Fishing is a popular recreation among Darwin locals. Visitors fish for the barramundi, an iconic fish in the region. This fish thrives in the Mary River, Daly River, and South and East Alligator River.
Blue-water fishing is also available off the coast of Darwin; Spanish mackerel, black jewfish, queenfish, and snapper are found in the area. Lake Alexander is a man-made swimming lake at East Point Reserve.
Darwin has extensive parks and gardens. These include the George Brown Darwin Botanic Gardens, East Point Reserve, Casuarina Coastal Reserve, Charles Darwin National Park, Knuckey Lagoons Conservation Reserve, Leanyer Recreation Park, the Nightcliff Foreshore, Bicentennial Park and the Jingili Water Gardens.
Darwin is a popular bird-watching site, with locations such as the George Brown Darwin Botanic Gardens, East Point Reserve, Buffalo Creek, Leanyer Ponds, and Knuckey Lagoon. Slightly further from the city is one of the best birding sites in the country, Fogg Dam Conservation Reserve.
Some species of native mammals are more abundant in Darwin than in the surrounding native forest and woodland ecosystems of the region, including the common brushtail possum and black-footed tree-rat. This is likely due to the presence of well-watered gardens and parks, the absence of frequent fires, and the availability of denning sites (e.g. the roofs of houses).
Darwin is also home to many species of frogs and reptiles. There are more species of snake in Darwin than any other Australian capital city, with 34 non-marine snake species found in the region, of which 23 have been recorded by professional snake catchers in Darwin itself. Fortunately for the citizens of Darwin, a far smaller proportion of these snakes are highly venomous than is typically found in other cities, due to the low numbers of front-fanged elapid species and dominance of relatively harmless pythons and colubrid species. Of the 23 more regularly encountered snake species in Darwin, it seems that species with broader habitat and dietary preferences, as well as a penchant for arboreality, are associated with more frequent human–snake interactions. Shifts in snake behaviour or movement also occur throughout the year, with species specific differences in abundance and occurrence in certain months.
The Marrara Sports Complex near the airport has stadiums for Australian rules (TIO Stadium), cricket, rugby league, football, basketball (and indoor court sports), athletics and field hockey. Every two years since 1991 (excluding 2003 due to the SARS outbreak), Darwin has hosted the Arafura Games, a major regional sporting event. In July 2003, the city hosted its first international test cricket match between Australia and Bangladesh, followed by Australia and Sri Lanka in 2004.
Australian rules is played all year round and the Territory's premier league competition, the Northern Territory Football League is based in Darwin. Australian Football League clubs generally sell a handful of games to the Northern Territory each year, some of which are played at Marrara Oval. Darwin is part of a bid for a Northern Territory AFL license for proposed entry into the competition by 2028 at the earliest. The Darwin based Indigenous All-Stars have participated in the AFL pre-season competition. In 2003, a record crowd of 17,500 attended a pre-season game between the All-Stars and Carlton Football Club at Marrara.
Rugby League and Rugby Union club competitions are played in Darwin each year, organised by the NTRL and NTRU respectively. The Darwin Hottest Sevens in the World tournament is hosted in Darwin each January, with Rugby Sevens club teams from countries including Australia, New Zealand, Papua New Guinea, Malaysia, and Singapore competing. Darwin's Hottest 7s is the richest Rugby 7s tournament in the Southern Hemisphere.
Darwin hosts a round of the Supercars Championship every year, bringing thousands of motorsports fans to the Hidden Valley Raceway. Also in Hidden Valley, adjacent to the road-racing circuit, is Darwin's dirt track racing venue, Northline Speedway. The speedway has hosted a number of Australian Championships over the years for different categories including Sprintcars, Speedcars, and Super Sedans.
The Darwin Cup culminating on the first Monday of August is a popular horse race event for Darwin and draws large crowds every year to Fannie Bay Racecourse. While it is not as popular as the Melbourne Cup, it does draw a crowd and, in 2003, Sky Racing began televising most of the races. The Darwin Cup day is a public holiday for the Northern Territory (Picnic Day public holiday).
There is one greyhound racing track in Darwin at Winnellie Park on Hook Road. It is the only track in the Northern Territory.
In 2022, the Darwin Salties basketball club will debut in the Queensland-based NBL1 North competition, making the NBL1 the first Australian sport league to have clubs based in and playing out of every state and territory in Australia.
Darwin's major newspapers are the Northern Territory News (Monday–Saturday), The Sunday Territorian (Sunday), and the national daily, The Australian (Monday–Friday) and The Weekend Australian (Saturday), all published by News Corp. Free weekly community newspapers include Sun Newspapers (delivered in Darwin, Palmerston and Litchfield), and published by the NT News. Another newspaper, the Centralian Advocate (1947–present), is printed in Darwin and trucked to Alice Springs.
Former publications in (or connected to) Darwin include:
Five free-to-air channels service Darwin. Commercial television channels are provided by Seven Darwin (Seven Network affiliate), Nine Darwin (formerly branded as Channel 8) and Ten Darwin (Network Ten relay), which launched on 28 April 2008. The two government-owned national broadcast services in Darwin are the ABC and SBS. Subscription television services Foxtel via Cable and Fetch TV via IPTV are available in the Darwin/Palmerston/Litchfield areas.
Darwin has radio stations on AM and FM frequencies, as well as on DAB+ (digital radio). ABC stations include ABC Local Radio (105.7 FM), ABC Radio National (657 AM), ABC News Radio (102.5 FM), ABC Classic (107.3 FM) and Triple J (103.3 FM). SBS Radio (100.9 FM) also broadcasts its national radio network to Darwin. There are three commercial radio stations, Hot 100, Mix 104.9 and Top Country 92.3. Other stations in Darwin include university-based station Territory FM 104.1, dance music station KIK FM 91.5, Palmerston FM 88.0 and Niche Radio 87.6 Non-English stations include Arabic-language channel 2ME 1638 AM, Chinese-language channel 3CW 1701 AM, Greek-language channel 2MM 1656AM, Italian-language channel Rete Italia 1476 AM and Spanish-language channel Radio Austral 90.7 FM. Indigenous community-based stations Radio Larrakia 94.5 FM and Radio Yolngu 1530 AM. The two sports stations TAB Radio 1242 AM and SEN 1611 AM. As well as Christian stations Faith 88.4 FM, Rhema 97.7 FM and Vision Radio 1323 AM.
The Territory's public transport services are managed by the Department of Lands and Planning, Public Transport Division. Darwin has a bus network serviced by a range of contracted bus operators, which provides transport to the main suburbs of Darwin.
Darwin has no commuter rail system, but long-distance passenger rail services do operate out of the city. The Alice Springs-Darwin railway line was completed in 2003, linking Darwin to Adelaide. The first service ran in 2004. The Ghan passenger train service from Adelaide via Alice Springs and Katherine runs once per week in each direction, with some exceptions.
Historically, the North Australia Railway carried passengers and freight from Darwin into the interior, reaching Pine Creek in 1889, Katherine in 1917, and Birdum in 1929. It was closed due to declining traffic in 1976.
Darwin International Airport, in the suburb of Eaton, is Darwin's only airport, which shares its runways with the Royal Australian Air Force's RAAF Base Darwin.
Darwin can be reached via the Stuart Highway, which runs the length of the Northern Territory from Darwin through Katherine, Tennant Creek, Alice Springs, and on to Adelaide. Other major roads in Darwin include Tiger Brennan Drive, Amy Johnson Avenue, Dick Ward Drive, Bagot Road, Trower Road, and McMillans Road. Bus service in the greater Darwin area is provided by Darwinbus.
Ferries leave from Port Darwin to island locations, mainly for tourists. A ferry service to the Tiwi Islands, the Arafura Pearl, operates from Cullen Bay.
Darwin has a deepwater port, East Arm Wharf, which opened in 2000. It has 754 metres (2,474 ft) of wharfline and is capable of handling Panamax-sized ships of a maximum length of 274 metres (899 ft) and a DWT of up to 80,000 tonnes (88,000 short tons).
The Government of the Northern Territory Department of Health and Families oversees one public hospital in the Darwin metropolitan region. The Royal Darwin Hospital, in Tiwi, is the city's major teaching and referral hospital, and the largest in the Northern Territory.
There is one major private hospital, Darwin Private Hospital, in Tiwi, adjacent to the Royal Darwin Hospital. Darwin Private Hospital is operated and owned by Healthscope Ltd, a private hospital corporation.
A new hospital called Palmerston Regional Hospital was opened in August 2018 to help ease the pressure of patient numbers at the Royal Darwin Hospital.
Water storage, supply and power for Darwin is managed by Power and Water Corporation, which is owned by the Government of the Northern Territory. The corporation is also responsible for management of sewage and the major water catchments in the region. Water is mainly stored in the largest dam, The Darwin River Dam, which holds up to 90% of Darwin's water supply. For many years, Darwin's principal water supply came from Manton Dam.
Darwin and its suburbs, Palmerston and Katherine, are powered by the Channel Island Power Station, the Northern Territory's largest power plant, and the Weddell Power Station.
Darwin once had Australia's only international connection to the outside world in the form of an overseas telegraph cable, connecting Darwin to Java. The southern section of the cable connected Darwin with Adelaide and was known as the overland telegraph line. In 2022, the Northern Territory Government announced that an international undersea cable system would land into Darwin, directly connecting it to Indonesia, Singapore, the United States and Timor Leste. The new cable system, representing an investment of $700 million, is expected to create a new digital economy as it is coupled with recent announcements on Data Centre Investment into Darwin. The plans for Darwin for Data Centres and International cables are outlined in the Northern Territory's Digital Strategy the Terabit Territory. | [
{
"paragraph_id": 0,
"text": "Darwin (/ˈdɑːrwɪn/ DAR-win; Larrakia: Garramilla) is the capital city of the Northern Territory, Australia. With a population of 139,902 at the 2021 census, the city contains most of the sparsely populated Northern Territory's residents. It is the smallest, wettest, and most northerly of the Australian capital cities and serves as the Top End's regional centre.",
"title": ""
},
{
"paragraph_id": 1,
"text": "Darwin's proximity to Southeast Asia makes it a key link between Australia and countries such as Indonesia and East Timor. The Stuart Highway begins in Darwin and extends southerly across central Australia through Tennant Creek and Alice Springs, concluding in Port Augusta, South Australia. The city is built upon a low bluff overlooking Darwin Harbour. Darwin's suburbs begin at Lee Point in the north and stretch to Berrimah in the east. The Stuart Highway extends to Darwin's eastern satellite city of Palmerston and its suburbs.",
"title": ""
},
{
"paragraph_id": 2,
"text": "The Darwin region, like much of the Top End, has a tropical climate, with a wet and dry season. A period known locally as \"the build up\" leading up to Darwin's wet season sees temperature and humidity increase. Darwin's wet season typically arrives in late November to early December and brings with it heavy monsoonal downpours, spectacular lightning displays, and increased cyclone activity. During the dry season, the city has clear skies and mild sea breezes from the harbour.",
"title": ""
},
{
"paragraph_id": 3,
"text": "The Larrakia people are the traditional owners of the Darwin area and Aboriginal people are a significant proportion of the population. On 9 September 1839, HMS Beagle sailed into Darwin Harbour during its survey of the area. John Clements Wickham named the region \"Port Darwin\" in honour of their former shipmate Charles Darwin, who had sailed with them on the ship's previous voyage. The settlement there became the town of Palmerston in 1869, but was renamed Darwin in 1911. The city has been almost entirely rebuilt four times, following devastation caused by a cyclone in 1897, another one in 1937, Japanese air raids during World War II, and Cyclone Tracy in 1974.",
"title": ""
},
{
"paragraph_id": 4,
"text": "The Aboriginal people of the Larrakia language group are the traditional custodians and earliest known inhabitants of the greater Darwin area. Their name for the area is Garramilla, pronounced /ɡɑːrəmɪlə/ and meaning \"white stone\", referring to the colour of rock and sea cliffs found in the area. They had trading routes with Southeast Asia (see Macassan contact with Australia) and imported goods from as far afield as South and Western Australia. Established songlines penetrated throughout the country, allowing stories and histories to be told and retold along the routes. The extent of shared songlines and history of multiple clan groups within this area is contestable.",
"title": "History"
},
{
"paragraph_id": 5,
"text": "The Dutch visited Australia's northern coastline in the 1600s and landed on the Tiwi Islands only to be repelled by the Tiwi peoples. The Dutch created the first European maps of the area. This accounts for the Dutch names in the area, such as Arnhem Land and Groote Eylandt. During this period, Dutch explorers named the region around Darwin—sometimes including nearby Kimberley—variations of \"Van Diemen's Land\", after the VOC governor-general Anthony van Diemen. This should not be confused with the more general and prolonged use of the same name for Tasmania.",
"title": "History"
},
{
"paragraph_id": 6,
"text": "The first British person to see Darwin harbour appears to have been Lieutenant John Lort Stokes of HMS Beagle on 9 September 1839. The ship's captain, Commander John Clements Wickham, named the port after Charles Darwin, the British naturalist who had sailed with him when he served as first lieutenant on the earlier second expedition of the Beagle.",
"title": "History"
},
{
"paragraph_id": 7,
"text": "In 1863, the Northern Territory was transferred from New South Wales to South Australia. In 1864 South Australia sent B. T. Finniss north as Government Resident to survey and found a capital for its new territory. Finniss chose a site at Escape Cliffs, near the entrance to Adelaide River, about 60 kilometres (37 mi) northeast of the modern city. This attempt was short-lived, and the settlement abandoned by 1865. On 5 February 1869, George Goyder, the Surveyor-General of South Australia, established a small settlement of 135 people at Port Darwin between Fort Hill and the escarpment. Goyder named the settlement Palmerston after British Prime Minister Lord Palmerston. In 1870, the first poles for the Overland Telegraph were erected in Darwin, connecting Australia to the rest of the world. The discovery of gold by employees of the Australian Overland Telegraph Line digging holes for telegraph poles at Pine Creek in the 1880s spawned a gold rush, which further boosted the colony's development.",
"title": "History"
},
{
"paragraph_id": 8,
"text": "In February 1872 the brigantine Alexandra was the first private vessel to sail from an English port directly to Darwin, carrying people many of whom were coming to recent gold finds.",
"title": "History"
},
{
"paragraph_id": 9,
"text": "In early 1875 Darwin's white population had grown to approximately 300 because of the gold rush. On 17 February 1875 the SS Gothenburg left Darwin en route for Adelaide. The approximately 88 passengers and 34 crew (surviving records vary) included government officials, circuit-court judges, Darwin residents taking their first furlough, and miners. While travelling south along the north Queensland coast, the Gothenburg encountered a cyclone-strength storm and was wrecked on a section of the Great Barrier Reef. Only 22 men survived, while between 98 and 112 people perished. Many passengers who perished were Darwin residents, and news of the tragedy severely affected the small community, which reportedly took several years to recover.",
"title": "History"
},
{
"paragraph_id": 10,
"text": "In the 1870s, relatively large numbers of Chinese settled at least temporarily in the Northern Territory; many were contracted to work the goldfields and later to build the Palmerston to Pine Creek railway. By 1888 there were 6,122 Chinese in the Northern Territory, mostly in or around Darwin. The early Chinese settlers were mainly from Guangdong Province. The Chinese community established Darwin Chinatown. At the end of the 19th century, anti-Chinese feelings grew in response to the 1890s economic depression, and the White Australia policy meant many Chinese left the territory. But some stayed, became British subjects, and established a commercial base in Darwin.",
"title": "History"
},
{
"paragraph_id": 11,
"text": "The Northern Territory was initially settled and administered by South Australia, until its transfer to the Commonwealth in 1911. In the same year, the city's official name changed from Palmerston to Darwin.",
"title": "History"
},
{
"paragraph_id": 12,
"text": "The period between 1911 and 1919 was filled with political turmoil, particularly with trade union unrest, which culminated on 17 December 1918. Led by Harold Nelson, some 1,000 demonstrators marched to Government House at Liberty Square in Darwin, where they burnt an effigy of the Administrator of the Northern Territory, John Gilruth, and demanded his resignation. The incident became known as the Darwin Rebellion. Their grievances were against the two main Northern Territory employers: Vestey's Meatworks and the federal government. Both Gilruth and the Vestey company left Darwin soon afterward.",
"title": "History"
},
{
"paragraph_id": 13,
"text": "On 18 October 1918, during the Spanish flu pandemic, the SS Mataram sailing from Singapore with infectious diseases arrived in Darwin.",
"title": "History"
},
{
"paragraph_id": 14,
"text": "In 1931, the 17 remaining patients from the leprosarium at Cossack, Western Australia were moved to Darwin, after it closed down. It was at a time when many Aboriginal people who were thought to have leprosy or other infectious diseases were sent to lock hospitals and leprosariums under the Aborigines Act 1905, which gave the Chief Protector of Aborigines powers to arrest and send any Indigenous person suspected of having a range of diseases to one of these institutions.",
"title": "History"
},
{
"paragraph_id": 15,
"text": "Around 10,000 Australian and other Allied troops arrived in Darwin at the outset of World War II to defend Australia's northern coast. On 19 February 1942 at 0957, 188 Japanese warplanes attacked Darwin in two waves. It was the same fleet that had bombed Pearl Harbor, though considerably more bombs were dropped on Darwin than on Pearl Harbor. The attack killed at least 243 people and caused immense damage to the town, airfields, and aircraft. These were by far the most serious attacks on Australia in time of war, in terms of fatalities and damage. They were the first of many raids on Darwin.",
"title": "History"
},
{
"paragraph_id": 16,
"text": "Darwin Chinatown which lay within the heart of Darwin was razed to the ground by the Japanese bombing and was never rebuilt. Northern Territory administrator Aubrey Abbott wanted to eliminate the Chinese community and forcibly seized their land as it was considered prime real estate.",
"title": "History"
},
{
"paragraph_id": 17,
"text": "Darwin was further developed after the war, with sealed roads constructed connecting the region to Alice Springs to the south and Mount Isa to the southeast, and Manton Dam built in the south to provide the city with water. On Australia Day (26 January) 1959, Darwin was granted city status.",
"title": "History"
},
{
"paragraph_id": 18,
"text": "On 25 December 1974, Darwin was struck by Cyclone Tracy, which killed 71 people and destroyed over 70% of the city's buildings, including many old stone buildings such as the Palmerston Town Hall, which could not withstand the lateral forces the winds generated. After the disaster, 30,000 of the population of 46,000 were evacuated in the biggest airlift in Australia's history. The town was rebuilt with newer materials and techniques during the late 1970s by the Darwin Reconstruction Commission, led by former Brisbane Lord mayor Clem Jones. A satellite city of Palmerston was built 20 km (12 mi) east of Darwin in the early 1980s.",
"title": "History"
},
{
"paragraph_id": 19,
"text": "On 17 September 2003, the Adelaide–Darwin railway was completed, with the opening of the Alice Springs–Darwin standard gauge line.",
"title": "History"
},
{
"paragraph_id": 20,
"text": "Darwin hosted many of aviation's early pioneers. On 10 December 1919, Captain Ross Smith and his crew landed in Darwin and won a £10,000 prize from the Australian government for completing the first flight from London to Australia in under 30 days. Smith and his crew flew a Vickers Vimy, G-EAOU, and landed on an airstrip that has become Ross Smith Avenue.",
"title": "History"
},
{
"paragraph_id": 21,
"text": "Other aviation pioneers include Amy Johnson, Amelia Earhart, Sir Charles Kingsford Smith and Bert Hinkler. The original QANTAS Empire Airways Ltd Hangar, a registered heritage site, was part of the original Darwin Civil Aerodrome in Parap and is now a museum that still bears scars from the bombing of Darwin during World War II.",
"title": "History"
},
{
"paragraph_id": 22,
"text": "Darwin was home to Australian and U.S. pilots during the war, with airstrips built in and around Darwin. Today Darwin provides a staging ground for military exercises.",
"title": "History"
},
{
"paragraph_id": 23,
"text": "Darwin was a compulsory stopover and checkpoint in the London-to-Melbourne Centenary Air Race in 1934. The official name of the race was the MacRobertson Air Race. Winners of the race were Tom Campbell Black and C. W. A. Scott.",
"title": "History"
},
{
"paragraph_id": 24,
"text": "The following is an excerpt from Time magazine, 29 October 1934:",
"title": "History"
},
{
"paragraph_id": 25,
"text": "Third Day. Biggest sensation of the race came just before dawn on the third day, when burly Lieutenant Scott and dapper Captain Black flew their scarlet Comet into Darwin. They had covered the last 300 miles [480 km] over water on one motor, risked death landing on a field made soggy by the first rain in seven months. Said sandy-haired Lieutenant Scott: \"We've had a devil of a trip.\" But they had flown 9000 miles [14000 km] in two days, had broken the England to Australia record of 162 hr. in the unbelievable time of 52hr. 33 min., were only 2000 miles [3200 km] from their goal at Melbourne.",
"title": "History"
},
{
"paragraph_id": 26,
"text": "The Australian Aviation Heritage Centre is about 8 km (5 mi) from the city centre on the Stuart Highway and is one of only three places outside the United States where a B-52 bomber (on permanent loan from the United States Air Force) is on public display.",
"title": "History"
},
{
"paragraph_id": 27,
"text": "Darwin is a coastal city, situated along the western shoreline of the Northern Territory. The water meets the land from the Beagle Gulf, which extends out into the Timor Sea. The central business district occupies a low bluff overlooking Darwin Harbour to the south, beyond which lie East Arm, Middle Arm, Northern Territory, and, across the gulf, West Arm. Middle Arm has an industrial precinct on the peninsula, which is being promoted as a sustainable development area that will include plants for industries such as low-emission petrochemicals, renewable hydrogen, and carbon capture storage. The city is flanked by Frances Bay to the east and Cullen Bay to the west.",
"title": "Geography"
},
{
"paragraph_id": 28,
"text": "The rest of the city is relatively flat and low-lying, and areas bordering the coast are home to recreational reserves, extensive beaches, and excellent fishing.",
"title": "Geography"
},
{
"paragraph_id": 29,
"text": "Darwin and its suburbs spread in an approximately triangular shape, with the older southwestern suburbs—and the city itself—forming one corner, the newer northern suburbs another, and the eastern suburbs, progressing towards Palmerston, forming the third.",
"title": "Geography"
},
{
"paragraph_id": 30,
"text": "The older part of Darwin is separated from the newer northern suburbs by Darwin International Airport and RAAF Base Darwin. Palmerston is a satellite city 20 km (12 mi) east of Darwin that was established in the 1980s and is one of Australia's fastest-growing municipalities. Darwin's rural areas, including Howard Springs, Humpty Doo and Berry Springs, are experiencing strong growth.",
"title": "Geography"
},
{
"paragraph_id": 31,
"text": "Darwin's central business district (CBD) is bounded by Daly Street in the northwest, McMinn Street in the northeast, Mitchell Street on the southwest, and Bennett Street on the southeast. The CBD has been the focus of a number of major projects, such as the billion-dollar redevelopment of the Stokes Hill wharf waterfront area, including a convention centre with seating for 1,500 people and approximately 4,000 square metres (43,000 sq ft) of exhibition space. The developers announced that this includes hotels, residential apartments, and public space. The city's main industrial areas are along the Stuart Highway toward Palmerston, centred on Winnellie. The area'a largest shopping precinct is Casuarina Square.",
"title": "Geography"
},
{
"paragraph_id": 32,
"text": "The most expensive residential areas stand along the coast in suburbs such as the marina of Cullen Bay, Larrakeyah, Bayview and Brinkin. These low-lying regions are at risk during cyclones and higher tides, but adequate drainage and stringent building regulations have reduced the potential damage to buildings or injury to residents. The inner northern suburbs are home to lower-income households, although low-income Territory Housing units are scattered throughout the metropolitan area. The suburb of Lyons was part of a multi-stage land release and development in the Northern Suburbs; planning, development and construction took place from 2004 to 2009. More recent developments near Lyons subdivision includes the suburb of Muirhead.",
"title": "Geography"
},
{
"paragraph_id": 33,
"text": "Darwin has a tropical savanna climate (Köppen Aw) with distinct wet and dry seasons, and the average maximum temperature is similar year round. The Australian Building Codes Board classifies it as Climate Zone 1 based on its very humid summers and warm winters. The dry season runs from about May to September, during which nearly every day is sunny, and afternoon relative humidity averages around 30%.",
"title": "Geography"
},
{
"paragraph_id": 34,
"text": "The driest period of the year, seeing about 5 mm (0.20 in) of monthly rainfall on average, is between May and September. In the coolest months, June and July, the daily minimum temperature may dip as low as 14 °C (57 °F), but very rarely lower, and a temperature lower than 10 °C (50 °F) has never been recorded in the city centre. Outer suburbs away from the coast occasionally record temperatures as low as 5 °C (41 °F) in the dry season. For a 147‑day period during the 2012 dry season, from 5 May to 29 September, Darwin recorded no precipitation. Prolonged periods of no precipitation are common in the dry season in Northern Australia (particularly in the Northern Territory and northern regions of Western Australia), although a no-rainfall event of this extent is rare. The 3pm dewpoint average in the wet season is around 24.0 °C (75.2 °F).",
"title": "Geography"
},
{
"paragraph_id": 35,
"text": "Extreme temperatures at the Darwin Post Office Station have ranged from 40.4 °C (104.7 °F) on 17 October 1892 to 13.4 °C (56.1 °F) on 25 June 1891; extreme temperatures at the Darwin Airport station (which is farther from the coast and routinely records cooler temperatures than the post office station, which is in Darwin's CBD) have ranged from 38.9 °C (102.0 °F) on 18 October 1982 to 10.4 °C (50.7 °F) on 29 July 1942. The highest minimum temperature on record is 30.7 °C (87.3 °F) on 18 January 1928 for the post office station and 29.7 °C (85.5 °F) on both 25 November 1987 and 17 December 2014 for the airport station. The lowest maximum temperature on record is 18.4 °C (65.1 °F) on 3 June 1904 for the post office station and 21.1 °C (70.0 °F) on 14 July 1968 for the airport station.",
"title": "Geography"
},
{
"paragraph_id": 36,
"text": "The wet season is associated with tropical cyclones and monsoon rains. Most rainfall occurs between December and March (the summer), when thunderstorms are common and afternoon relative humidity averages over 70 percent during the wettest months. It does not rain every day during the wet season, but most days have plentiful cloud cover; January averages under six hours of bright sunshine daily. Darwin's highest daily rainfall verified by the Bureau of Meteorology is 367.6 millimetres (14.47 in), which fell when Cyclone Carlos bore down on the Darwin area on 16 February 2011. February 2011 was also Darwin's wettest month ever recorded, with 1,110.2 millimetres (43.71 in) at the airport.",
"title": "Geography"
},
{
"paragraph_id": 37,
"text": "The hottest months are October and November, just before the onset of the main rain season. The temperature is usually below 35 °C (95 °F), but the heat index sometimes rises above 45 °C (113 °F), because of humidity levels that most find uncomfortable. Because of its long dry season, Darwin has the second-highest average daily hours of sunshine (8.4) of any Australian capital, with the most sunshine from April to November; only Perth, Western Australia, averages more (8.8). The sun passes directly overhead in mid-October and mid-February.",
"title": "Geography"
},
{
"paragraph_id": 38,
"text": "The average temperature of the sea ranges from 25.8 °C (78.4 °F) in July to 31.5 °C (88.7 °F) in December.",
"title": "Geography"
},
{
"paragraph_id": 39,
"text": "Darwin occupies one of the most lightning-prone areas in Australia. On 31 January 2002 an early-morning squall line produced over 5,000 cloud-to-ground lightning strikes within a 60-kilometre (37 mi) radius of Darwin alone—about three times the amount of lightning that Perth experiences on average in an entire year.",
"title": "Geography"
},
{
"paragraph_id": 40,
"text": "Darwin's population changed after the Second World War. Like many other Australian cities, Darwin experienced influxes from Europe, with significant numbers of Italians and Greeks during the 1960s and 1970s. It also began to experience an influx from other European countries, which included the Dutch, Germans, and many others. A significant proportion of Darwin's residents are recent immigrants from Asia, including the peoples of East Timor.",
"title": "Demographics"
},
{
"paragraph_id": 41,
"text": "At the 2016 census, the most commonly nominated ancestries were:",
"title": "Demographics"
},
{
"paragraph_id": 42,
"text": "38.3% of the population at the 2016 census was born overseas. The five largest groups of overseas-born were from the Philippines (3.6%), England (3.1%), New Zealand (2.1%), India (2%) and Greece (0.9%).",
"title": "Demographics"
},
{
"paragraph_id": 43,
"text": "8.7% of the population, or 11,960 people, identified as Indigenous Australians (Aboriginal Australians and/or Torres Strait Islanders) in 2016. This is the largest proportion of any Australian capital city.",
"title": "Demographics"
},
{
"paragraph_id": 44,
"text": "At the 2016 census, 58% of the population spoke only English at home. Other languages spoken at home include Tagalog (3.7%), Greek (3.5%), Mandarin (2.0%), Nepali (1.2%), Indonesian (1.0%), Australian Aboriginal languages (1.0%), Malayalam (0.9%), Vietnamese (0.8%), Cantonese (0.7%), Italian (0.6%), Portuguese (0.5%, mostly spoken by Timorese), and Tamil (0.5%).",
"title": "Demographics"
},
{
"paragraph_id": 45,
"text": "In 2011, the Darwin population averaged 33 years old (compared to the national average of around 37), to a large extent because of the military presence and because many people opt to retire elsewhere.",
"title": "Demographics"
},
{
"paragraph_id": 46,
"text": "As of 2008, Christianity had the most adherents in Darwin, with 56,613 followers accounting for 49.5 percent of the population. The largest denominations of Christianity are Roman Catholicism (24,538 or 21.5 percent), Anglicanism (14,028 or 12.3 percent) and Greek Orthodoxy (2,964 or 2.6 percent). Buddhists, Muslims, Hindus and Jews account for 3.2 percent of Darwin's population. There were 26,695 or 23.3 percent of people professing no religion.",
"title": "Demographics"
},
{
"paragraph_id": 47,
"text": "The Darwin City Council (incorporated under the Northern Territory Local Government Act 1993) governs the City of Darwin, which takes in the CBD and the suburbs. The city has been governed by a city council form of government since 1957. The council consists of 13 elected members, the lord mayor, and 12 aldermen.",
"title": "Law and government"
},
{
"paragraph_id": 48,
"text": "The City of Darwin electorate is organised into four electoral units or wards. The wards are Chan, Lyons, Richardson, and Waters. The constituents of each ward are directly responsible for electing three aldermen. Constituents of all wards are directly responsible for electing the Lord Mayor of Darwin. Since the August 2017 council elections, the mayor has been Kon Vatskalis.",
"title": "Law and government"
},
{
"paragraph_id": 49,
"text": "The rest of the Darwin area is divided into two local government areas—the Palmerston City Council and the Shire of Coomalie. These areas have elected councils that are responsible for functions delegated to them by the Northern Territory Government, such as planning and garbage collection.",
"title": "Law and government"
},
{
"paragraph_id": 50,
"text": "The Legislative Assembly of the Northern Territory convenes in Darwin in the Northern Territory Parliament House. Government House, the official residence of the Administrator of the Northern Territory, is on the Esplanade.",
"title": "Law and government"
},
{
"paragraph_id": 51,
"text": "Darwin is split between nine electoral divisions in the Legislative Assembly—Port Darwin, Fannie Bay, Fong Lim, Nightcliff, Sanderson, Johnston, Casuarina, Wanguri, and Karama. Historically, Darwin voters elected Country Liberal Party members, but since the turn of the 21st century, voters have often selected Labor members, particularly in the more diverse northern section; as of the 2020 Northern Territory general election, all of Darwin's nine Legislative Assembly electoral divisions are held by Labor, with Labor also holding both the Northern Territory's federal electorates, Solomon and Lingiari.",
"title": "Law and government"
},
{
"paragraph_id": 52,
"text": "Also on the Esplanade is the Supreme Court of the Northern Territory. Darwin has a Magistrate's Court is on the corner of Cavenagh and Bennett streets, quite close to the Darwin City Council Chambers.",
"title": "Law and government"
},
{
"paragraph_id": 53,
"text": "Darwin's police force are members of the Northern Territory Police, under the NT Police Darwin Metropolitan Command. The Darwin urban centre includes Darwin City and the associated suburbs from Buffalo Creek, Berrimah, and East Arm westwards, representing around 35% of the Northern Territory's population. Palmerston urban centre closely approximates the Palmerston Local Government Area, and represents approximately 13% of the Northern Territory's population.",
"title": "Law and government"
},
{
"paragraph_id": 54,
"text": "Darwin has had a history of alcohol abuse and violent crime, with 6,000 assaults in 2009, of which 350 resulted in broken jaws and noses—more than anywhere else in the world, according to the Royal Darwin Hospital.",
"title": "Law and government"
},
{
"paragraph_id": 55,
"text": "Mitchell Street, with its numerous pubs, clubs and other entertainment venues, was one of the areas policed by the CitySafe Unit, officially launched by the NT Chief Minister Paul Henderson on 25 February 2009. It was credited with success in tackling alcohol abuse linked to crime, and the NT police were looking at establishing a specialist licensing enforcement unit in 2010.",
"title": "Law and government"
},
{
"paragraph_id": 56,
"text": "The First Response Patrol, run by Larrakia Nation, which helps move homeless Indigenous women out of dangerous situations, was credited with the decline in sexual assaults in 2009. The service operates every day from 5am to 2am.",
"title": "Law and government"
},
{
"paragraph_id": 57,
"text": "In the 10 months between 1 October 2018, the date that the alcohol floor price and various other measures were imposed by the NT government following the Riley Review, and 31 July 2019, alcohol-related assaults dropped by 16% and domestic violence by 9% in the Darwin area.",
"title": "Law and government"
},
{
"paragraph_id": 58,
"text": "The rate of offending in most categories of crime dropped in the Darwin urban area between 2018 and 2019, with the notable exceptions of motor vehicle theft and break-ins (both up about 12%). Apart from sexual assault, which rose from 21 to 46, all other categories of crime declined in Palmerston.",
"title": "Law and government"
},
{
"paragraph_id": 59,
"text": "The two largest economic sectors are mining and tourism. Given its location, Darwin serves as a gateway for Australian travellers to Asia.",
"title": "Economy"
},
{
"paragraph_id": 60,
"text": "Mining and energy industry production exceeds $2.5 billion per annum. The most important mineral resources are gold, zinc, and bauxite, along with manganese and many others. The energy production is mostly off-shore with oil and natural gas from the Timor Sea, although there are significant uranium deposits near Darwin. Tourism employs 8% of Darwin residents and is expected to grow as domestic and international tourists now spend time in Darwin during the wet and dry seasons. Federal spending is also a major contributor to the local economy. Darwin's importance as a port is expected to grow, due to the increased exploitation of petroleum in the nearby Timor Sea and to the completion of the railway link and continued expansion in trade with Asia. During 2005, a number of major construction projects started in Darwin. One is the redevelopment of the Wharf Precinct, which includes a large convention and exhibition centre, apartment housing including Outrigger Pandanas and Evolution on Gardiner, retail and entertainment outlets including a large wave pool and safe swimming lagoon. The Chinatown project has also started with plans to construct Chinese-themed retail and dining outlets.",
"title": "Economy"
},
{
"paragraph_id": 61,
"text": "Tourism is one of Darwin's largest industries and a major employment sector for the Northern Territory. In 2005–2006, 1.38 million people visited the Northern Territory. They stayed for 9.2 million nights and spent over $1.5 billion. The tourism industry directly employed 8,391 Territorians in June 2006, and, when indirect employment is included, tourism typically accounts for more than 14,000 jobs across the Territory.",
"title": "Economy"
},
{
"paragraph_id": 62,
"text": "Darwin is a hub for tours to Kakadu National Park, Litchfield National Park and Katherine Gorge. The year is traditionally divided into the wet and dry seasons, but there are up to six traditional seasons in Darwin. It is warm and sunny from May to September. Humidity rises during the green season, from October to April, bringing thunderstorms and monsoonal rains that rejuvenate the landscape. Tourism is largely seasonal, with most tourists visiting during the cooler dry season, from April to September.",
"title": "Economy"
},
{
"paragraph_id": 63,
"text": "The military presence in both Darwin and the wider Northern Territory is a substantial source of employment. On 16 November 2011, Prime Minister Julia Gillard and President Barack Obama announced that the United States would station troops in Australia for the first time since World War II. The agreement between the U.S. and Australia would involve a contingent of 250 Marines arriving in Darwin in 2012, with the total number rising to a maximum of 2,500 troops by 2017 on six-month rotations as well as a supporting air element including F-22 Raptors, F-35 Joint Strike Fighters and KC-135 refuellers. China and Indonesia have expressed concern about the decision. Some analysts have argued that an expanded U.S. presence could pose a threat to security. Gillard announced that the first 200 U.S. Marines had arrived in Darwin from Hawaii on 3 April 2012. In 2013, further news of other expansion vectors aired in U.S. media, with no comment or confirmation from Australian authorities. The agreement between the two governments remains hidden from public scrutiny. Marine numbers based in Darwin increased to more than 1,150 by 2014. In a 2019 telephone survey of local residents, 51% of respondents had positive feelings about the U.S. troop presence, with 6% responding negatively. In late 2021, the U.S. Department of Defense signed a contract to create a 300 million litres (79,000,000 US gal) fuel storage facility at East Arm.",
"title": "Economy"
},
{
"paragraph_id": 64,
"text": "Darwin hosts biennial multi-nation exercises named \"Pitch Black\"; in 2014 this involved military personnel from Australia, New Zealand, Singapore, Thailand, United Arab Emirates, and the United States.",
"title": "Economy"
},
{
"paragraph_id": 65,
"text": "Education is overseen territory-wide by the Department of Education and Training (DET), whose role is to continually improve education outcomes for all students, with a focus on Indigenous students.",
"title": "Education"
},
{
"paragraph_id": 66,
"text": "Darwin is served by a number of public and private schools that cater to local and overseas students. Over 16,500 primary and secondary students are enrolled in schools in Darwin, with 10,524 students attending primary education, and 5,932 students attending secondary education. Over 12,089 students are enrolled in government schools, and 2,124 in independent schools.",
"title": "Education"
},
{
"paragraph_id": 67,
"text": "There were 9,764 students attending schools in the City of Darwin area. 6,045 students attended primary schools and 3,719 attended secondary schools. Over 7,161 students are enrolled in government schools and 1,108 in independent schools. There are over 35 primary and pre-schools and 12 secondary schools, including both government and non-government. Most schools in the city are secular, but there are a small number of Catholic and Lutheran institutions. Students intending to complete their secondary education work toward either the Northern Territory Certificate of Education, the Victorian Certificate of Education, or the Victorian Certificate of Applied Learning (the latter two are offered only at Haileybury Rendall School). Until the sale and restructuring of Kormilda College in 2018, it was the only school to offer the International Baccalaureate in the Northern Territory.",
"title": "Education"
},
{
"paragraph_id": 68,
"text": "Schools have been restructured into Primary, Middle, and High schools since the beginning of 2007.",
"title": "Education"
},
{
"paragraph_id": 69,
"text": "Darwin's largest university is Charles Darwin University, the Northern Territory's central provider of tertiary education. It has both vocational and academic courses, acting as both a university and an Institute of TAFE. More than 5,500 students are enrolled in tertiary and further education courses.",
"title": "Education"
},
{
"paragraph_id": 70,
"text": "Darwin is also home to several private vocational colleges, including Alana Kaye College, which focuses on Early Childhood Education and Care, and Latitude College, which offers Commercial Cookery and Hospitality Management.",
"title": "Education"
},
{
"paragraph_id": 71,
"text": "As Darwin was destroyed by cyclones several times and suffered severe bomb damage during World War II, few historic buildings remain in town. The Administrator's Office dating from 1883 was used as a law court and as a police station and was only slightly damaged by bombs, but in 1974, the cyclone completely destroyed it. In 1979, it was decided to rebuild, and the reconstruction was finished in 1981. The building houses government offices today. Opposite the building, Survivors Lookout offers a view of the marina.",
"title": "Architecture"
},
{
"paragraph_id": 72,
"text": "In a park in the south of the CBD, the ruin of the Town Hall built in 1883 and destroyed by the cyclone in 1974 can be seen. Browns Mart is a stone building dating from 1880 opposite the park. Browns Mart was originally used in many different activities including commerce, storage, shipping and insurance agency, mining exchange and meetings of local organisations but it was transformed into a theatre.",
"title": "Architecture"
},
{
"paragraph_id": 73,
"text": "One of Darwin's most prominent buildings is the Chinese Temple, which was founded in 1887 and damaged by cyclones in 1897 and in 1937. It was severely damaged by bombs in 1942 and rebuilt after the war. On 24 December 1974 the cyclone completely destroyed it. Reconstruction was completed in 1978.",
"title": "Architecture"
},
{
"paragraph_id": 74,
"text": "There are various modern churches in Darwin. St Mary's Star of the Sea Roman Catholic Cathedral was inaugurated in 1962. Christ Church Anglican Cathedral was rebuilt in 1977 after being severely damaged by bombs in 1942 and destroyed by Cyclone Tracy in 1974. The Uniting Memorial Church was built in 1960.",
"title": "Architecture"
},
{
"paragraph_id": 75,
"text": "The Darwin Symphony Orchestra was assembled in 1989 and has performed throughout the Territory. The Darwin Theatre Company is a locally produced professional theatre production company, performing locally and nationally.",
"title": "Arts and culture"
},
{
"paragraph_id": 76,
"text": "The Darwin Entertainment Centre is the city's main concert venue and hosts theatre and orchestral performances. Other theatres include the Darwin Convention Centre, which opened in July 2008. The Darwin Convention Centre is part of the $1.1 billion Darwin Waterfront project.",
"title": "Arts and culture"
},
{
"paragraph_id": 77,
"text": "The Northern Territory Museum and Art Gallery (MAGNT) in Darwin gives an overview of the history of the area, including exhibits on Cyclone Tracy and the boats of the Pacific Islands. The MAGNT also organises the annual Telstra National Aboriginal and Torres Strait Islander Art Award, the longest-running Indigenous art award in Australia. The MAGNT also manages the Defence of Darwin Experience, a multi-media installation that tells the story of the Japanese air raids on Darwin during World War II.",
"title": "Arts and culture"
},
{
"paragraph_id": 78,
"text": "The NT Dance Company is led by choreographer Gary Lang, who has been artistic director since 2012. Lang previously taught at many leading dance companies, including Bangarra Dance Theatre, after studying dance at NAISDA in Sydney and working as a dancer for years. The company has a strong focus on culture, and also works with disadvantaged young Indigenous people.",
"title": "Arts and culture"
},
{
"paragraph_id": 79,
"text": "Local and visiting bands can be heard at venues including the Darwin Entertainment Centre, The Vic Hotel, Happy Yess, and Brown's Mart. Artists such as Jessica Mauboy and The Groovesmiths call Darwin home.",
"title": "Arts and culture"
},
{
"paragraph_id": 80,
"text": "The multiculturalism of Darwin has helped make Southeast Asian noodle broth laksa the city's favourite meal.",
"title": "Arts and culture"
},
{
"paragraph_id": 81,
"text": "Weekly markets include the popular Mindil Beach Sunset Market (Thursdays and Sundays during the dry season); Parap Market; Nightcliff Market; and Rapid Creek market.",
"title": "Other entertainment"
},
{
"paragraph_id": 82,
"text": "Darwin's only casino opened in 1979 as the Don Casino, operating out of the Don Hotel on Cavenagh Street. The present site of the hotel and casino on Darwin's Mindil Beach opened in 1983, at which point gambling operations ceased at the Don Hotel and resumed at the newly built facilities. The new hotel and casino was named Mindil Beach Casino until 1985, when the name changed to the Diamond Beach Hotel Casino. Upon its acquisition by MGM Grand the hotel was rebranded as the MGM Grand Darwin, before it changed to Skycity Darwin after Skycity Entertainment Group purchased the hotel in 2004.",
"title": "Other entertainment"
},
{
"paragraph_id": 83,
"text": "Mitchell Street in the central business district is lined with nightclubs, takeaways, and restaurants. This is the city's entertainment hub. There are several smaller theatres, three cinema complexes (CBD, Casuarina, and Palmerston), and the Deckchair Cinema. An open-air cinema operates through the dry season, from April to October, screening independent and arthouse films.",
"title": "Other entertainment"
},
{
"paragraph_id": 84,
"text": "During the months of October–May the sea contains deadly box jellyfish, known locally as stingers or sea wasps. Saltwater crocodiles are common in all waterways surrounding Darwin and are occasionally found in Darwin Harbour and on local beaches. An active trapping program is carried out by the NT Government to limit numbers of crocodiles within the Darwin urban waterway area.",
"title": "Recreation"
},
{
"paragraph_id": 85,
"text": "The city has many kilometres of beaches, including the Casuarina Beach and renowned Mindil Beach, home of the Mindil Beach markets. Darwin City Council has designated an area of Casuarina Beach as a free beach, which has been designated as a nudist beach area since 1976.",
"title": "Recreation"
},
{
"paragraph_id": 86,
"text": "Bundilla Beach was formerly named Vesteys Beach, as it was one of the beaches overlooked by Vestey's Meatworks, which existed from 1914 to 1920 and was involved in the Darwin rebellion. In March 2021, the beach was formally renamed Bundilla Beach, the name by which it had long been known to the traditional owners, the Larrakia people.",
"title": "Recreation"
},
{
"paragraph_id": 87,
"text": "The Darwin Surf Life Saving Club operates longboats and surf skis and provides events and lifesaving accreditations.",
"title": "Recreation"
},
{
"paragraph_id": 88,
"text": "Fishing is a popular recreation among Darwin locals. Visitors fish for the barramundi, an iconic fish in the region. This fish thrives in the Mary River, Daly River, and South and East Alligator River.",
"title": "Recreation"
},
{
"paragraph_id": 89,
"text": "Blue-water fishing is also available off the coast of Darwin; Spanish mackerel, black jewfish, queenfish, and snapper are found in the area. Lake Alexander is a man-made swimming lake at East Point Reserve.",
"title": "Recreation"
},
{
"paragraph_id": 90,
"text": "Darwin has extensive parks and gardens. These include the George Brown Darwin Botanic Gardens, East Point Reserve, Casuarina Coastal Reserve, Charles Darwin National Park, Knuckey Lagoons Conservation Reserve, Leanyer Recreation Park, the Nightcliff Foreshore, Bicentennial Park and the Jingili Water Gardens.",
"title": "Recreation"
},
{
"paragraph_id": 91,
"text": "Darwin is a popular bird-watching site, with locations such as the George Brown Darwin Botanic Gardens, East Point Reserve, Buffalo Creek, Leanyer Ponds, and Knuckey Lagoon. Slightly further from the city is one of the best birding sites in the country, Fogg Dam Conservation Reserve.",
"title": "Recreation"
},
{
"paragraph_id": 92,
"text": "Some species of native mammals are more abundant in Darwin than in the surrounding native forest and woodland ecosystems of the region, including the common brushtail possum and black-footed tree-rat. This is likely due to the presence of well-watered gardens and parks, the absence of frequent fires, and the availability of denning sites (e.g. the roofs of houses).",
"title": "Recreation"
},
{
"paragraph_id": 93,
"text": "Darwin is also home to many species of frogs and reptiles. There are more species of snake in Darwin than any other Australian capital city, with 34 non-marine snake species found in the region, of which 23 have been recorded by professional snake catchers in Darwin itself. Fortunately for the citizens of Darwin, a far smaller proportion of these snakes are highly venomous than is typically found in other cities, due to the low numbers of front-fanged elapid species and dominance of relatively harmless pythons and colubrid species. Of the 23 more regularly encountered snake species in Darwin, it seems that species with broader habitat and dietary preferences, as well as a penchant for arboreality, are associated with more frequent human–snake interactions. Shifts in snake behaviour or movement also occur throughout the year, with species specific differences in abundance and occurrence in certain months.",
"title": "Recreation"
},
{
"paragraph_id": 94,
"text": "The Marrara Sports Complex near the airport has stadiums for Australian rules (TIO Stadium), cricket, rugby league, football, basketball (and indoor court sports), athletics and field hockey. Every two years since 1991 (excluding 2003 due to the SARS outbreak), Darwin has hosted the Arafura Games, a major regional sporting event. In July 2003, the city hosted its first international test cricket match between Australia and Bangladesh, followed by Australia and Sri Lanka in 2004.",
"title": "Sports"
},
{
"paragraph_id": 95,
"text": "Australian rules is played all year round and the Territory's premier league competition, the Northern Territory Football League is based in Darwin. Australian Football League clubs generally sell a handful of games to the Northern Territory each year, some of which are played at Marrara Oval. Darwin is part of a bid for a Northern Territory AFL license for proposed entry into the competition by 2028 at the earliest. The Darwin based Indigenous All-Stars have participated in the AFL pre-season competition. In 2003, a record crowd of 17,500 attended a pre-season game between the All-Stars and Carlton Football Club at Marrara.",
"title": "Sports"
},
{
"paragraph_id": 96,
"text": "Rugby League and Rugby Union club competitions are played in Darwin each year, organised by the NTRL and NTRU respectively. The Darwin Hottest Sevens in the World tournament is hosted in Darwin each January, with Rugby Sevens club teams from countries including Australia, New Zealand, Papua New Guinea, Malaysia, and Singapore competing. Darwin's Hottest 7s is the richest Rugby 7s tournament in the Southern Hemisphere.",
"title": "Sports"
},
{
"paragraph_id": 97,
"text": "Darwin hosts a round of the Supercars Championship every year, bringing thousands of motorsports fans to the Hidden Valley Raceway. Also in Hidden Valley, adjacent to the road-racing circuit, is Darwin's dirt track racing venue, Northline Speedway. The speedway has hosted a number of Australian Championships over the years for different categories including Sprintcars, Speedcars, and Super Sedans.",
"title": "Sports"
},
{
"paragraph_id": 98,
"text": "The Darwin Cup culminating on the first Monday of August is a popular horse race event for Darwin and draws large crowds every year to Fannie Bay Racecourse. While it is not as popular as the Melbourne Cup, it does draw a crowd and, in 2003, Sky Racing began televising most of the races. The Darwin Cup day is a public holiday for the Northern Territory (Picnic Day public holiday).",
"title": "Sports"
},
{
"paragraph_id": 99,
"text": "There is one greyhound racing track in Darwin at Winnellie Park on Hook Road. It is the only track in the Northern Territory.",
"title": "Sports"
},
{
"paragraph_id": 100,
"text": "In 2022, the Darwin Salties basketball club will debut in the Queensland-based NBL1 North competition, making the NBL1 the first Australian sport league to have clubs based in and playing out of every state and territory in Australia.",
"title": "Sports"
},
{
"paragraph_id": 101,
"text": "Darwin's major newspapers are the Northern Territory News (Monday–Saturday), The Sunday Territorian (Sunday), and the national daily, The Australian (Monday–Friday) and The Weekend Australian (Saturday), all published by News Corp. Free weekly community newspapers include Sun Newspapers (delivered in Darwin, Palmerston and Litchfield), and published by the NT News. Another newspaper, the Centralian Advocate (1947–present), is printed in Darwin and trucked to Alice Springs.",
"title": "Media"
},
{
"paragraph_id": 102,
"text": "Former publications in (or connected to) Darwin include:",
"title": "Media"
},
{
"paragraph_id": 103,
"text": "Five free-to-air channels service Darwin. Commercial television channels are provided by Seven Darwin (Seven Network affiliate), Nine Darwin (formerly branded as Channel 8) and Ten Darwin (Network Ten relay), which launched on 28 April 2008. The two government-owned national broadcast services in Darwin are the ABC and SBS. Subscription television services Foxtel via Cable and Fetch TV via IPTV are available in the Darwin/Palmerston/Litchfield areas.",
"title": "Media"
},
{
"paragraph_id": 104,
"text": "Darwin has radio stations on AM and FM frequencies, as well as on DAB+ (digital radio). ABC stations include ABC Local Radio (105.7 FM), ABC Radio National (657 AM), ABC News Radio (102.5 FM), ABC Classic (107.3 FM) and Triple J (103.3 FM). SBS Radio (100.9 FM) also broadcasts its national radio network to Darwin. There are three commercial radio stations, Hot 100, Mix 104.9 and Top Country 92.3. Other stations in Darwin include university-based station Territory FM 104.1, dance music station KIK FM 91.5, Palmerston FM 88.0 and Niche Radio 87.6 Non-English stations include Arabic-language channel 2ME 1638 AM, Chinese-language channel 3CW 1701 AM, Greek-language channel 2MM 1656AM, Italian-language channel Rete Italia 1476 AM and Spanish-language channel Radio Austral 90.7 FM. Indigenous community-based stations Radio Larrakia 94.5 FM and Radio Yolngu 1530 AM. The two sports stations TAB Radio 1242 AM and SEN 1611 AM. As well as Christian stations Faith 88.4 FM, Rhema 97.7 FM and Vision Radio 1323 AM.",
"title": "Media"
},
{
"paragraph_id": 105,
"text": "The Territory's public transport services are managed by the Department of Lands and Planning, Public Transport Division. Darwin has a bus network serviced by a range of contracted bus operators, which provides transport to the main suburbs of Darwin.",
"title": "Transport"
},
{
"paragraph_id": 106,
"text": "Darwin has no commuter rail system, but long-distance passenger rail services do operate out of the city. The Alice Springs-Darwin railway line was completed in 2003, linking Darwin to Adelaide. The first service ran in 2004. The Ghan passenger train service from Adelaide via Alice Springs and Katherine runs once per week in each direction, with some exceptions.",
"title": "Transport"
},
{
"paragraph_id": 107,
"text": "Historically, the North Australia Railway carried passengers and freight from Darwin into the interior, reaching Pine Creek in 1889, Katherine in 1917, and Birdum in 1929. It was closed due to declining traffic in 1976.",
"title": "Transport"
},
{
"paragraph_id": 108,
"text": "Darwin International Airport, in the suburb of Eaton, is Darwin's only airport, which shares its runways with the Royal Australian Air Force's RAAF Base Darwin.",
"title": "Transport"
},
{
"paragraph_id": 109,
"text": "Darwin can be reached via the Stuart Highway, which runs the length of the Northern Territory from Darwin through Katherine, Tennant Creek, Alice Springs, and on to Adelaide. Other major roads in Darwin include Tiger Brennan Drive, Amy Johnson Avenue, Dick Ward Drive, Bagot Road, Trower Road, and McMillans Road. Bus service in the greater Darwin area is provided by Darwinbus.",
"title": "Transport"
},
{
"paragraph_id": 110,
"text": "Ferries leave from Port Darwin to island locations, mainly for tourists. A ferry service to the Tiwi Islands, the Arafura Pearl, operates from Cullen Bay.",
"title": "Transport"
},
{
"paragraph_id": 111,
"text": "Darwin has a deepwater port, East Arm Wharf, which opened in 2000. It has 754 metres (2,474 ft) of wharfline and is capable of handling Panamax-sized ships of a maximum length of 274 metres (899 ft) and a DWT of up to 80,000 tonnes (88,000 short tons).",
"title": "Transport"
},
{
"paragraph_id": 112,
"text": "The Government of the Northern Territory Department of Health and Families oversees one public hospital in the Darwin metropolitan region. The Royal Darwin Hospital, in Tiwi, is the city's major teaching and referral hospital, and the largest in the Northern Territory.",
"title": "Infrastructure"
},
{
"paragraph_id": 113,
"text": "There is one major private hospital, Darwin Private Hospital, in Tiwi, adjacent to the Royal Darwin Hospital. Darwin Private Hospital is operated and owned by Healthscope Ltd, a private hospital corporation.",
"title": "Infrastructure"
},
{
"paragraph_id": 114,
"text": "A new hospital called Palmerston Regional Hospital was opened in August 2018 to help ease the pressure of patient numbers at the Royal Darwin Hospital.",
"title": "Infrastructure"
},
{
"paragraph_id": 115,
"text": "Water storage, supply and power for Darwin is managed by Power and Water Corporation, which is owned by the Government of the Northern Territory. The corporation is also responsible for management of sewage and the major water catchments in the region. Water is mainly stored in the largest dam, The Darwin River Dam, which holds up to 90% of Darwin's water supply. For many years, Darwin's principal water supply came from Manton Dam.",
"title": "Infrastructure"
},
{
"paragraph_id": 116,
"text": "Darwin and its suburbs, Palmerston and Katherine, are powered by the Channel Island Power Station, the Northern Territory's largest power plant, and the Weddell Power Station.",
"title": "Infrastructure"
},
{
"paragraph_id": 117,
"text": "Darwin once had Australia's only international connection to the outside world in the form of an overseas telegraph cable, connecting Darwin to Java. The southern section of the cable connected Darwin with Adelaide and was known as the overland telegraph line. In 2022, the Northern Territory Government announced that an international undersea cable system would land into Darwin, directly connecting it to Indonesia, Singapore, the United States and Timor Leste. The new cable system, representing an investment of $700 million, is expected to create a new digital economy as it is coupled with recent announcements on Data Centre Investment into Darwin. The plans for Darwin for Data Centres and International cables are outlined in the Northern Territory's Digital Strategy the Terabit Territory.",
"title": "Infrastructure"
}
] | Darwin is the capital city of the Northern Territory, Australia. With a population of 139,902 at the 2021 census, the city contains most of the sparsely populated Northern Territory's residents. It is the smallest, wettest, and most northerly of the Australian capital cities and serves as the Top End's regional centre. Darwin's proximity to Southeast Asia makes it a key link between Australia and countries such as Indonesia and East Timor. The Stuart Highway begins in Darwin and extends southerly across central Australia through Tennant Creek and Alice Springs, concluding in Port Augusta, South Australia. The city is built upon a low bluff overlooking Darwin Harbour. Darwin's suburbs begin at Lee Point in the north and stretch to Berrimah in the east. The Stuart Highway extends to Darwin's eastern satellite city of Palmerston and its suburbs. The Darwin region, like much of the Top End, has a tropical climate, with a wet and dry season. A period known locally as "the build up" leading up to Darwin's wet season sees temperature and humidity increase. Darwin's wet season typically arrives in late November to early December and brings with it heavy monsoonal downpours, spectacular lightning displays, and increased cyclone activity. During the dry season, the city has clear skies and mild sea breezes from the harbour. The Larrakia people are the traditional owners of the Darwin area and Aboriginal people are a significant proportion of the population. On 9 September 1839, HMS Beagle sailed into Darwin Harbour during its survey of the area. John Clements Wickham named the region "Port Darwin" in honour of their former shipmate Charles Darwin, who had sailed with them on the ship's previous voyage. The settlement there became the town of Palmerston in 1869, but was renamed Darwin in 1911. The city has been almost entirely rebuilt four times, following devastation caused by a cyclone in 1897, another one in 1937, Japanese air raids during World War II, and Cyclone Tracy in 1974. | 2001-09-08T03:18:42Z | 2023-12-27T14:11:26Z | [
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8,409 | Dictator | A dictator is a political leader who possesses absolute power. A dictatorship is a state ruled by one dictator or by a small clique. The word originated as the title of a Roman dictator elected by the Roman Senate to rule the republic in times of emergency.
Like the term tyrant, and to a lesser degree autocrat, dictator came to be used almost exclusively as a non-titular term for oppressive rule. In modern usage the term dictator is generally used to describe a leader who holds or abuses an extraordinary amount of personal power. Dictatorships are often characterised by some of the following: suspension of elections and civil liberties; proclamation of a state of emergency; rule by decree; repression of political opponents; not abiding by the procedures of the rule of law; and the existence of a cult of personality centered on the leader. Dictatorships are often one-party or dominant-party states.
A wide variety of leaders coming to power in different kinds of regimes, such as one-party or dominant-party states and civilian governments under a personal rule, have been described as dictators.
The word dictator comes from the Latin language word dictātor, agent noun from dictare (dictāt-, past participial stem of dictāre dictate v. + -or -or suffix). A dictator was a Roman magistrate given sole power for a limited duration. Originally an emergency legal appointment in the Roman Republic and the Etruscan culture, the term dictator did not have the negative meaning it has now.
It started to get its modern negative meaning with Cornelius Sulla's ascension to the dictatorship following Sulla's civil war, making himself the first Dictator in Rome in more than a century (during which the office was ostensibly abolished) as well as de facto eliminating the time limit and need of senatorial acclamation. He avoided a major constitutional crisis by resigning the office after about one year, dying a few years later. Julius Caesar followed Sulla's example in 49 BC and in February 44 BC was proclaimed Dictator perpetuo, "Dictator in perpetuity", officially doing away with any limitations on his power, which he kept until his assassination the following month.
Following Caesar's assassination, his heir Augustus was offered the title of dictator, but he declined it. Later successors also declined the title of dictator, and usage of the title soon diminished among Roman rulers.
The term comes from Latin dictator, having same meaning as in English, originating in dicto 'I dictate', which comes from dicio 'exert authority; make a decision'.
As late as the second half of the 19th century, the term dictator had occasional positive implications. For example, during the Hungarian Revolution of 1848, the national leader Lajos Kossuth was often referred to as dictator, without any negative connotations, by his supporters and detractors alike, although his official title was that of regent-president. When creating a provisional executive in Sicily during the Expedition of the Thousand in 1860, Giuseppe Garibaldi officially assumed the title of "Dictator" (see Dictatorship of Garibaldi). Shortly afterwards, during the 1863 January uprising in Poland, "Dictator" was also the official title of four leaders, the first being Ludwik Mierosławski.
Past that time, however, the term dictator assumed an invariably negative connotation. In popular usage, a dictatorship is often associated with brutality and oppression. As a result, it is often also used as a term of abuse against political opponents. The term has also come to be associated with megalomania. Many dictators create a cult of personality around themselves and they have also come to grant themselves increasingly grandiloquent titles and honours. For instance, Idi Amin Dada, who had been a British army lieutenant prior to Uganda's independence from Britain in October 1962, subsequently styled himself "His Excellency, President for Life, Field Marshal Al Hadji Doctor Idi Amin Dada, VC, DSO, MC, Conqueror of the British Empire in Africa in General and Uganda in Particular". In the movie The Great Dictator (1940), Charlie Chaplin satirized not only Adolf Hitler but the institution of dictatorship itself.
A benevolent dictatorship refers to a government in which an authoritarian leader exercises absolute political power over the state but is perceived to do so with regard for the benefit of the population as a whole, standing in contrast to the decidedly malevolent stereotype of a dictator. A benevolent dictator may allow for some civil liberties or democratic decision-making to exist, such as through public referendums or elected representatives with limited power, and often makes preparations for a transition to genuine democracy during or after their term. The label has been applied to leaders such as Mustafa Kemal Atatürk of Turkey (1923–38), Josip Broz Tito of SFR Yugoslavia (1953–80), and Lee Kuan Yew of Singapore (1959–90).
The association between a dictator and the military is a common one. Many dictators take great pains to emphasize their connections with the military and they often wear military uniforms. In some cases, this is perfectly legitimate; for instance, Francisco Franco was a general in the Spanish Army before he became Chief of State of Spain, and Manuel Noriega was officially commander of the Panamanian Defense Forces. In other cases, the association is mere pretense.
Some dictators have been masters of crowd manipulation, such as Benito Mussolini and Adolf Hitler. Others were more prosaic speakers, such as Joseph Stalin and Francisco Franco. Typically, the dictator's people seize control of all media, censor or destroy the opposition, and give strong doses of propaganda daily, often built around a cult of personality.
Mussolini and Hitler used similar, modest titles referring to them as "the Leader". Mussolini used "Il Duce" and Hitler was generally referred to as "der Führer", both meaning 'Leader' in Italian and German respectively. Franco used a similar title "El Caudillo" ("the Head", 'the chieftain') and for Stalin his adopted name, meaning "Man of Steel", became synonyms with his role as the absolute leader. For Mussolini, Hitler, and Franco, the use of modest, non-traditional titles displayed their absolute power even stronger as they did not need any, not even a historic legitimacy either. However, in the case of Franco, the title "Caudillo" did have a longer history for political-military figures in both Latin America and Spain. Franco also used the phrase "By the Grace of God" on coinage or other material displaying him as Caudillo, whereas Hitler and Mussolini rarely used such monarchical-associated language or imagery.
The usage of the term dictator in western media has been criticized by the left-leaning organization Fairness & Accuracy in Reporting as "Code for Government We Don't Like". According to them, leaders that would generally be considered authoritarian but are allied with the US such as Paul Biya or Nursultan Nazarbayev are rarely referred to as "dictators", while leaders of countries opposed to U.S. policy such as Nicolás Maduro or Bashar al-Assad have the term applied to them much more liberally.
Because of its negative and pejorative connotations, modern authoritarian leaders very rarely (if ever) use the term dictator in their formal titles, instead they most often simply have title of president. In the 19th century, however, its official usage was more common:
Over time, dictators have been known to use tactics that violate human rights. For example, under the Soviet dictator Joseph Stalin, government policy was enforced by secret police and the Gulag system of prison labour camps. Most Gulag inmates were not political prisoners, although significant numbers of political prisoners could be found in the camps at any one time. Data collected from Soviet archives gives the death toll from Gulags as 1,053,829. Other human rights abuses by the Soviet state included human experimentation, the use of psychiatry as a political weapon and the denial of freedom of religion, assembly, speech and association.
Similar crimes were committed during Chairman Mao Zedong's rule over the People's Republic of China during China's Cultural Revolution, where Mao set out to purge dissidents, primarily through the use of youth groups strongly committed to his cult of personality, and during Augusto Pinochet's junta in Chile. Some dictators have been associated with genocide on certain races or groups; the most notable and wide-reaching example is the Holocaust, Adolf Hitler's genocide of eleven million people, of whom six million were Jews. Later on in Democratic Kampuchea, General Secretary Pol Pot and his policies killed an estimated 1.7 million people (out of a population of 7 million) during his four-year dictatorship. As a result, Pol Pot is sometimes described as "the Hitler of Cambodia" and "a genocidal tyrant".
The International Criminal Court issued an arrest warrant for Sudan's military dictator Omar al-Bashir over alleged war crimes in Darfur. Syrian dictator Bashar al-Assad, known for perpetrating numerous chemical attacks, has been regarded as the deadliest war criminal of the 21st century for inflicting industrial-scale atrocities in the Syrian civil war. | [
{
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"text": "A dictator is a political leader who possesses absolute power. A dictatorship is a state ruled by one dictator or by a small clique. The word originated as the title of a Roman dictator elected by the Roman Senate to rule the republic in times of emergency.",
"title": ""
},
{
"paragraph_id": 1,
"text": "Like the term tyrant, and to a lesser degree autocrat, dictator came to be used almost exclusively as a non-titular term for oppressive rule. In modern usage the term dictator is generally used to describe a leader who holds or abuses an extraordinary amount of personal power. Dictatorships are often characterised by some of the following: suspension of elections and civil liberties; proclamation of a state of emergency; rule by decree; repression of political opponents; not abiding by the procedures of the rule of law; and the existence of a cult of personality centered on the leader. Dictatorships are often one-party or dominant-party states.",
"title": ""
},
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"text": "A wide variety of leaders coming to power in different kinds of regimes, such as one-party or dominant-party states and civilian governments under a personal rule, have been described as dictators.",
"title": ""
},
{
"paragraph_id": 3,
"text": "The word dictator comes from the Latin language word dictātor, agent noun from dictare (dictāt-, past participial stem of dictāre dictate v. + -or -or suffix). A dictator was a Roman magistrate given sole power for a limited duration. Originally an emergency legal appointment in the Roman Republic and the Etruscan culture, the term dictator did not have the negative meaning it has now.",
"title": "Etymology"
},
{
"paragraph_id": 4,
"text": "It started to get its modern negative meaning with Cornelius Sulla's ascension to the dictatorship following Sulla's civil war, making himself the first Dictator in Rome in more than a century (during which the office was ostensibly abolished) as well as de facto eliminating the time limit and need of senatorial acclamation. He avoided a major constitutional crisis by resigning the office after about one year, dying a few years later. Julius Caesar followed Sulla's example in 49 BC and in February 44 BC was proclaimed Dictator perpetuo, \"Dictator in perpetuity\", officially doing away with any limitations on his power, which he kept until his assassination the following month.",
"title": "Etymology"
},
{
"paragraph_id": 5,
"text": "Following Caesar's assassination, his heir Augustus was offered the title of dictator, but he declined it. Later successors also declined the title of dictator, and usage of the title soon diminished among Roman rulers.",
"title": "Etymology"
},
{
"paragraph_id": 6,
"text": "The term comes from Latin dictator, having same meaning as in English, originating in dicto 'I dictate', which comes from dicio 'exert authority; make a decision'.",
"title": "Etymology"
},
{
"paragraph_id": 7,
"text": "As late as the second half of the 19th century, the term dictator had occasional positive implications. For example, during the Hungarian Revolution of 1848, the national leader Lajos Kossuth was often referred to as dictator, without any negative connotations, by his supporters and detractors alike, although his official title was that of regent-president. When creating a provisional executive in Sicily during the Expedition of the Thousand in 1860, Giuseppe Garibaldi officially assumed the title of \"Dictator\" (see Dictatorship of Garibaldi). Shortly afterwards, during the 1863 January uprising in Poland, \"Dictator\" was also the official title of four leaders, the first being Ludwik Mierosławski.",
"title": "Modern era"
},
{
"paragraph_id": 8,
"text": "Past that time, however, the term dictator assumed an invariably negative connotation. In popular usage, a dictatorship is often associated with brutality and oppression. As a result, it is often also used as a term of abuse against political opponents. The term has also come to be associated with megalomania. Many dictators create a cult of personality around themselves and they have also come to grant themselves increasingly grandiloquent titles and honours. For instance, Idi Amin Dada, who had been a British army lieutenant prior to Uganda's independence from Britain in October 1962, subsequently styled himself \"His Excellency, President for Life, Field Marshal Al Hadji Doctor Idi Amin Dada, VC, DSO, MC, Conqueror of the British Empire in Africa in General and Uganda in Particular\". In the movie The Great Dictator (1940), Charlie Chaplin satirized not only Adolf Hitler but the institution of dictatorship itself.",
"title": "Modern era"
},
{
"paragraph_id": 9,
"text": "A benevolent dictatorship refers to a government in which an authoritarian leader exercises absolute political power over the state but is perceived to do so with regard for the benefit of the population as a whole, standing in contrast to the decidedly malevolent stereotype of a dictator. A benevolent dictator may allow for some civil liberties or democratic decision-making to exist, such as through public referendums or elected representatives with limited power, and often makes preparations for a transition to genuine democracy during or after their term. The label has been applied to leaders such as Mustafa Kemal Atatürk of Turkey (1923–38), Josip Broz Tito of SFR Yugoslavia (1953–80), and Lee Kuan Yew of Singapore (1959–90).",
"title": "Modern era"
},
{
"paragraph_id": 10,
"text": "The association between a dictator and the military is a common one. Many dictators take great pains to emphasize their connections with the military and they often wear military uniforms. In some cases, this is perfectly legitimate; for instance, Francisco Franco was a general in the Spanish Army before he became Chief of State of Spain, and Manuel Noriega was officially commander of the Panamanian Defense Forces. In other cases, the association is mere pretense.",
"title": "Modern era"
},
{
"paragraph_id": 11,
"text": "Some dictators have been masters of crowd manipulation, such as Benito Mussolini and Adolf Hitler. Others were more prosaic speakers, such as Joseph Stalin and Francisco Franco. Typically, the dictator's people seize control of all media, censor or destroy the opposition, and give strong doses of propaganda daily, often built around a cult of personality.",
"title": "Modern era"
},
{
"paragraph_id": 12,
"text": "Mussolini and Hitler used similar, modest titles referring to them as \"the Leader\". Mussolini used \"Il Duce\" and Hitler was generally referred to as \"der Führer\", both meaning 'Leader' in Italian and German respectively. Franco used a similar title \"El Caudillo\" (\"the Head\", 'the chieftain') and for Stalin his adopted name, meaning \"Man of Steel\", became synonyms with his role as the absolute leader. For Mussolini, Hitler, and Franco, the use of modest, non-traditional titles displayed their absolute power even stronger as they did not need any, not even a historic legitimacy either. However, in the case of Franco, the title \"Caudillo\" did have a longer history for political-military figures in both Latin America and Spain. Franco also used the phrase \"By the Grace of God\" on coinage or other material displaying him as Caudillo, whereas Hitler and Mussolini rarely used such monarchical-associated language or imagery.",
"title": "Modern era"
},
{
"paragraph_id": 13,
"text": "The usage of the term dictator in western media has been criticized by the left-leaning organization Fairness & Accuracy in Reporting as \"Code for Government We Don't Like\". According to them, leaders that would generally be considered authoritarian but are allied with the US such as Paul Biya or Nursultan Nazarbayev are rarely referred to as \"dictators\", while leaders of countries opposed to U.S. policy such as Nicolás Maduro or Bashar al-Assad have the term applied to them much more liberally.",
"title": "Modern era"
},
{
"paragraph_id": 14,
"text": "Because of its negative and pejorative connotations, modern authoritarian leaders very rarely (if ever) use the term dictator in their formal titles, instead they most often simply have title of president. In the 19th century, however, its official usage was more common:",
"title": "Modern usage in formal titles"
},
{
"paragraph_id": 15,
"text": "Over time, dictators have been known to use tactics that violate human rights. For example, under the Soviet dictator Joseph Stalin, government policy was enforced by secret police and the Gulag system of prison labour camps. Most Gulag inmates were not political prisoners, although significant numbers of political prisoners could be found in the camps at any one time. Data collected from Soviet archives gives the death toll from Gulags as 1,053,829. Other human rights abuses by the Soviet state included human experimentation, the use of psychiatry as a political weapon and the denial of freedom of religion, assembly, speech and association.",
"title": "Human rights abuses, war crimes and genocides"
},
{
"paragraph_id": 16,
"text": "Similar crimes were committed during Chairman Mao Zedong's rule over the People's Republic of China during China's Cultural Revolution, where Mao set out to purge dissidents, primarily through the use of youth groups strongly committed to his cult of personality, and during Augusto Pinochet's junta in Chile. Some dictators have been associated with genocide on certain races or groups; the most notable and wide-reaching example is the Holocaust, Adolf Hitler's genocide of eleven million people, of whom six million were Jews. Later on in Democratic Kampuchea, General Secretary Pol Pot and his policies killed an estimated 1.7 million people (out of a population of 7 million) during his four-year dictatorship. As a result, Pol Pot is sometimes described as \"the Hitler of Cambodia\" and \"a genocidal tyrant\".",
"title": "Human rights abuses, war crimes and genocides"
},
{
"paragraph_id": 17,
"text": "The International Criminal Court issued an arrest warrant for Sudan's military dictator Omar al-Bashir over alleged war crimes in Darfur. Syrian dictator Bashar al-Assad, known for perpetrating numerous chemical attacks, has been regarded as the deadliest war criminal of the 21st century for inflicting industrial-scale atrocities in the Syrian civil war.",
"title": "Human rights abuses, war crimes and genocides"
}
] | A dictator is a political leader who possesses absolute power. A dictatorship is a state ruled by one dictator or by a small clique. The word originated as the title of a Roman dictator elected by the Roman Senate to rule the republic in times of emergency. Like the term tyrant, and to a lesser degree autocrat, dictator came to be used almost exclusively as a non-titular term for oppressive rule. In modern usage the term dictator is generally used to describe a leader who holds or abuses an extraordinary amount of personal power. Dictatorships are often characterised by some of the following: suspension of elections and civil liberties; proclamation of a state of emergency; rule by decree; repression of political opponents; not abiding by the procedures of the rule of law; and the existence of a cult of personality centered on the leader. Dictatorships are often one-party or dominant-party states. A wide variety of leaders coming to power in different kinds of regimes, such as one-party or dominant-party states and civilian governments under a personal rule, have been described as dictators. | 2001-09-08T18:27:01Z | 2023-11-24T17:38:47Z | [
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8,410 | Decibel | The decibel (symbol: dB) is a relative unit of measurement equal to one tenth of a bel (B). It expresses the ratio of two values of a power or root-power quantity on a logarithmic scale. Two signals whose levels differ by one decibel have a power ratio of 10 (approximately 1.26) or root-power ratio of 10 (approximately 1.12).
The unit expresses a relative change or an absolute value. In the latter case, the numeric value expresses the ratio of a value to a fixed reference value; when used in this way, the unit symbol is often suffixed with letter codes that indicate the reference value. For example, for the reference value of 1 volt, a common suffix is "V" (e.g., "20 dBV").
Two principal types of scaling of the decibel are in common use. When expressing a power ratio, it is defined as ten times the logarithm in base 10. That is, a change in power by a factor of 10 corresponds to a 10 dB change in level. When expressing root-power quantities, a change in amplitude by a factor of 10 corresponds to a 20 dB change in level. The decibel scales differ by a factor of two, so that the related power and root-power levels change by the same value in linear systems, where power is proportional to the square of amplitude.
The definition of the decibel originated in the measurement of transmission loss and power in telephony of the early 20th century in the Bell System in the United States. The bel was named in honor of Alexander Graham Bell, but the bel is seldom used. Instead, the decibel is used for a wide variety of measurements in science and engineering, most prominently in acoustics, electronics, and control theory. In electronics, the gains of amplifiers, attenuation of signals, and signal-to-noise ratios are often expressed in decibels.
The decibel originates from methods used to quantify signal loss in telegraph and telephone circuits. Until the mid-1920s, the unit for loss was Miles of Standard Cable (MSC). 1 MSC corresponded to the loss of power over one mile (approximately 1.6 km) of standard telephone cable at a frequency of 5000 radians per second (795.8 Hz), and matched closely the smallest attenuation detectable to a listener. A standard telephone cable was "a cable having uniformly distributed resistance of 88 ohms per loop-mile and uniformly distributed shunt capacitance of 0.054 microfarads per mile" (approximately corresponding to 19 gauge wire).
In 1924, Bell Telephone Laboratories received a favorable response to a new unit definition among members of the International Advisory Committee on Long Distance Telephony in Europe and replaced the MSC with the Transmission Unit (TU). 1 TU was defined such that the number of TUs was ten times the base-10 logarithm of the ratio of measured power to a reference power. The definition was conveniently chosen such that 1 TU approximated 1 MSC; specifically, 1 MSC was 1.056 TU. In 1928, the Bell system renamed the TU into the decibel, being one tenth of a newly defined unit for the base-10 logarithm of the power ratio. It was named the bel, in honor of the telecommunications pioneer Alexander Graham Bell. The bel is seldom used, as the decibel was the proposed working unit.
The naming and early definition of the decibel is described in the NBS Standard's Yearbook of 1931:
Since the earliest days of the telephone, the need for a unit in which to measure the transmission efficiency of telephone facilities has been recognized. The introduction of cable in 1896 afforded a stable basis for a convenient unit and the "mile of standard" cable came into general use shortly thereafter. This unit was employed up to 1923 when a new unit was adopted as being more suitable for modern telephone work. The new transmission unit is widely used among the foreign telephone organizations and recently it was termed the "decibel" at the suggestion of the International Advisory Committee on Long Distance Telephony.
The decibel may be defined by the statement that two amounts of power differ by 1 decibel when they are in the ratio of 10 and any two amounts of power differ by N decibels when they are in the ratio of 10. The number of transmission units expressing the ratio of any two powers is therefore ten times the common logarithm of that ratio. This method of designating the gain or loss of power in telephone circuits permits direct addition or subtraction of the units expressing the efficiency of different parts of the circuit ...
In 1954, J. W. Horton argued that the use of the decibel as a unit for quantities other than transmission loss led to confusion, and suggested the name logit for "standard magnitudes which combine by multiplication", to contrast with the name unit for "standard magnitudes which combine by addition".
In April 2003, the International Committee for Weights and Measures (CIPM) considered a recommendation for the inclusion of the decibel in the International System of Units (SI), but decided against the proposal. However, the decibel is recognized by other international bodies such as the International Electrotechnical Commission (IEC) and International Organization for Standardization (ISO). The IEC permits the use of the decibel with root-power quantities as well as power and this recommendation is followed by many national standards bodies, such as NIST, which justifies the use of the decibel for voltage ratios. In spite of their widespread use, suffixes (such as in dBA or dBV) are not recognized by the IEC or ISO.
ISO 80000-3 describes definitions for quantities and units of space and time.
The IEC Standard 60027-3:2002 defines the following quantities. The decibel (dB) is one-tenth of a bel: 1 dB = 0.1 B. The bel (B) is 1⁄2 ln(10) nepers: 1 B = 1⁄2 ln(10) Np. The neper is the change in the level of a root-power quantity when the root-power quantity changes by a factor of e, that is 1 Np = ln(e) = 1, thereby relating all of the units as nondimensional natural log of root-power-quantity ratios, 1 dB = 0.115 13… Np = 0.115 13…. Finally, the level of a quantity is the logarithm of the ratio of the value of that quantity to a reference value of the same kind of quantity.
Therefore, the bel represents the logarithm of a ratio between two power quantities of 10:1, or the logarithm of a ratio between two root-power quantities of √10:1.
Two signals whose levels differ by one decibel have a power ratio of 10, which is approximately 1.25893, and an amplitude (root-power quantity) ratio of 10 (1.12202).
The bel is rarely used either without a prefix or with SI unit prefixes other than deci; it is preferred, for example, to use hundredths of a decibel rather than millibels. Thus, five one-thousandths of a bel would normally be written 0.05 dB, and not 5 mB.
The method of expressing a ratio as a level in decibels depends on whether the measured property is a power quantity or a root-power quantity; see Power, root-power, and field quantities for details.
When referring to measurements of power quantities, a ratio can be expressed as a level in decibels by evaluating ten times the base-10 logarithm of the ratio of the measured quantity to reference value. Thus, the ratio of P (measured power) to P0 (reference power) is represented by LP, that ratio expressed in decibels, which is calculated using the formula:
The base-10 logarithm of the ratio of the two power quantities is the number of bels. The number of decibels is ten times the number of bels (equivalently, a decibel is one-tenth of a bel). P and P0 must measure the same type of quantity, and have the same units before calculating the ratio. If P = P0 in the above equation, then LP = 0. If P is greater than P0 then LP is positive; if P is less than P0 then LP is negative.
Rearranging the above equation gives the following formula for P in terms of P0 and LP:
When referring to measurements of root-power quantities, it is usual to consider the ratio of the squares of F (measured) and F0 (reference). This is because the definitions were originally formulated to give the same value for relative ratios for both power and root-power quantities. Thus, the following definition is used:
The formula may be rearranged to give
Similarly, in electrical circuits, dissipated power is typically proportional to the square of voltage or current when the impedance is constant. Taking voltage as an example, this leads to the equation for power gain level LG:
where Vout is the root-mean-square (rms) output voltage, Vin is the rms input voltage. A similar formula holds for current.
The term root-power quantity is introduced by ISO Standard 80000-1:2009 as a substitute of field quantity. The term field quantity is deprecated by that standard and root-power is used throughout this article.
Although power and root-power quantities are different quantities, their respective levels are historically measured in the same units, typically decibels. A factor of 2 is introduced to make changes in the respective levels match under restricted conditions such as when the medium is linear and the same waveform is under consideration with changes in amplitude, or the medium impedance is linear and independent of both frequency and time. This relies on the relationship
holding. In a nonlinear system, this relationship does not hold by the definition of linearity. However, even in a linear system in which the power quantity is the product of two linearly related quantities (e.g. voltage and current), if the impedance is frequency- or time-dependent, this relationship does not hold in general, for example if the energy spectrum of the waveform changes.
For differences in level, the required relationship is relaxed from that above to one of proportionality (i.e., the reference quantities P0 and F0 need not be related), or equivalently,
must hold to allow the power level difference to be equal to the root-power level difference from power P1 and F1 to P2 and F2. An example might be an amplifier with unity voltage gain independent of load and frequency driving a load with a frequency-dependent impedance: the relative voltage gain of the amplifier is always 0 dB, but the power gain depends on the changing spectral composition of the waveform being amplified. Frequency-dependent impedances may be analyzed by considering the quantities power spectral density and the associated root-power quantities via the Fourier transform, which allows elimination of the frequency dependence in the analysis by analyzing the system at each frequency independently.
Since logarithm differences measured in these units often represent power ratios and root-power ratios, values for both are shown below. The bel is traditionally used as a unit of logarithmic power ratio, while the neper is used for logarithmic root-power (amplitude) ratio.
The unit dBW is often used to denote a ratio for which the reference is 1 W, and similarly dBm for a 1 mW reference point.
(31.62 V / 1 V) ≈ 1 kW / 1 W, illustrating the consequence from the definitions above that LG has the same value, 30 dB, regardless of whether it is obtained from powers or from amplitudes, provided that in the specific system being considered power ratios are equal to amplitude ratios squared.
A change in power ratio by a factor of 10 corresponds to a change in level of 10 dB. A change in power ratio by a factor of 2 or 1⁄2 is approximately a change of 3 dB. More precisely, the change is ±3.0103 dB, but this is almost universally rounded to 3 dB in technical writing. This implies an increase in voltage by a factor of √2 ≈ 1.4142. Likewise, a doubling or halving of the voltage, corresponding to a quadrupling or quartering of the power, is commonly described as 6 dB rather than ±6.0206 dB.
Should it be necessary to make the distinction, the number of decibels is written with additional significant figures. 3.000 dB corresponds to a power ratio of 10, or 1.9953, about 0.24% different from exactly 2, and a voltage ratio of 1.4125, 0.12% different from exactly √2. Similarly, an increase of 6.000 dB corresponds to the power ratio is 10 ≈ 3.9811, about 0.5% different from 4.
The decibel is useful for representing large ratios and for simplifying representation of multiplicative effects, such as attenuation from multiple sources along a signal chain. Its application in systems with additive effects is less intuitive, such as in the combined sound pressure level of two machines operating together. Care is also necessary with decibels directly in fractions and with the units of multiplicative operations.
The logarithmic scale nature of the decibel means that a very large range of ratios can be represented by a convenient number, in a manner similar to scientific notation. This allows one to clearly visualize huge changes of some quantity. See Bode plot and Semi-log plot. For example, 120 dB SPL may be clearer than "a trillion times more intense than the threshold of hearing".
Level values in decibels can be added instead of multiplying the underlying power values, which means that the overall gain of a multi-component system, such as a series of amplifier stages, can be calculated by summing the gains in decibels of the individual components, rather than multiply the amplification factors; that is, log(A × B × C) = log(A) + log(B) + log(C). Practically, this means that, armed only with the knowledge that 1 dB is a power gain of approximately 26%, 3 dB is approximately 2× power gain, and 10 dB is 10× power gain, it is possible to determine the power ratio of a system from the gain in dB with only simple addition and multiplication. For example:
However, according to its critics, the decibel creates confusion, obscures reasoning, is more related to the era of slide rules than to modern digital processing, and is cumbersome and difficult to interpret. Quantities in decibels are not necessarily additive, thus being "of unacceptable form for use in dimensional analysis". Thus, units require special care in decibel operations. Take, for example, carrier-to-noise-density ratio C/N0 (in hertz), involving carrier power C (in watts) and noise power spectral density N0 (in W/Hz). Expressed in decibels, this ratio would be a subtraction (C/N0)dB = CdB − N0dB. However, the linear-scale units still simplify in the implied fraction, so that the results would be expressed in dB-Hz.
According to Mitschke, "The advantage of using a logarithmic measure is that in a transmission chain, there are many elements concatenated, and each has its own gain or attenuation. To obtain the total, addition of decibel values is much more convenient than multiplication of the individual factors." However, for the same reason that humans excel at additive operation over multiplication, decibels are awkward in inherently additive operations:
if two machines each individually produce a sound pressure level of, say, 90 dB at a certain point, then when both are operating together we should expect the combined sound pressure level to increase to 93 dB, but certainly not to 180 dB!; suppose that the noise from a machine is measured (including the contribution of background noise) and found to be 87 dBA but when the machine is switched off the background noise alone is measured as 83 dBA. [...] the machine noise [level (alone)] may be obtained by 'subtracting' the 83 dBA background noise from the combined level of 87 dBA; i.e., 84.8 dBA.; in order to find a representative value of the sound level in a room a number of measurements are taken at different positions within the room, and an average value is calculated. [...] Compare the logarithmic and arithmetic averages of [...] 70 dB and 90 dB: logarithmic average = 87 dB; arithmetic average = 80 dB.
Addition on a logarithmic scale is called logarithmic addition, and can be defined by taking exponentials to convert to a linear scale, adding there, and then taking logarithms to return. For example, where operations on decibels are logarithmic addition/subtraction and logarithmic multiplication/division, while operations on the linear scale are the usual operations:
The logarithmic mean is obtained from the logarithmic sum by subtracting 10 log 10 2 {\displaystyle 10\log _{10}2} , since logarithmic division is linear subtraction.
Attenuation constants, in topics such as optical fiber communication and radio propagation path loss, are often expressed as a fraction or ratio to distance of transmission. In this case, dB/m represents decibel per meter, dB/mi represents decibel per mile, for example. These quantities are to be manipulated obeying the rules of dimensional analysis, e.g., a 100-meter run with a 3.5 dB/km fiber yields a loss of 0.35 dB = 3.5 dB/km × 0.1 km.
The human perception of the intensity of sound and light more nearly approximates the logarithm of intensity rather than a linear relationship (see Weber–Fechner law), making the dB scale a useful measure.
The decibel is commonly used in acoustics as a unit of sound pressure level. The reference pressure for sound in air is set at the typical threshold of perception of an average human and there are common comparisons used to illustrate different levels of sound pressure. As sound pressure is a root-power quantity, the appropriate version of the unit definition is used:
where prms is the root mean square of the measured sound pressure and pref is the standard reference sound pressure of 20 micropascals in air or 1 micropascal in water.
Use of the decibel in underwater acoustics leads to confusion, in part because of this difference in reference value.
Sound intensity is proportional to the square of sound pressure. Therefore the sound intensity level can also be defined as:
The human ear has a large dynamic range in sound reception. The ratio of the sound intensity that causes permanent damage during short exposure to that of the quietest sound that the ear can hear is equal to or greater than 1 trillion (10). Such large measurement ranges are conveniently expressed in logarithmic scale: the base-10 logarithm of 10 is 12, which is expressed as a sound intensity level of 120 dB re 1 pW/m. The reference values of I and p in air have been chosen such that this also corresponds to a sound pressure level of 120 dB re 20 μPa.
Since the human ear is not equally sensitive to all sound frequencies, the acoustic power spectrum is modified by frequency weighting (A-weighting being the most common standard) to get the weighted acoustic power before converting to a sound level or noise level in decibels.
The decibel is used in telephony and audio. Similarly to the use in acoustics, a frequency weighted power is often used. For audio noise measurements in electrical circuits, the weightings are called psophometric weightings.
In electronics, the decibel is often used to express power or amplitude ratios (as for gains) in preference to arithmetic ratios or percentages. One advantage is that the total decibel gain of a series of components (such as amplifiers and attenuators) can be calculated simply by summing the decibel gains of the individual components. Similarly, in telecommunications, decibels denote signal gain or loss from a transmitter to a receiver through some medium (free space, waveguide, coaxial cable, fiber optics, etc.) using a link budget.
The decibel unit can also be combined with a reference level, often indicated via a suffix, to create an absolute unit of electric power. For example, it can be combined with "m" for "milliwatt" to produce the "dBm". A power level of 0 dBm corresponds to one milliwatt, and 1 dBm is one decibel greater (about 1.259 mW).
In professional audio specifications, a popular unit is the dBu. This is relative to the root mean square voltage which delivers 1 mW (0 dBm) into a 600-ohm resistor, or √1 mW×600 Ω ≈ 0.775 VRMS. When used in a 600-ohm circuit (historically, the standard reference impedance in telephone circuits), dBu and dBm are identical.
In an optical link, if a known amount of optical power, in dBm (referenced to 1 mW), is launched into a fiber, and the losses, in dB (decibels), of each component (e.g., connectors, splices, and lengths of fiber) are known, the overall link loss may be quickly calculated by addition and subtraction of decibel quantities.
In spectrometry and optics, the blocking unit used to measure optical density is equivalent to −1 B.
In connection with video and digital image sensors, decibels generally represent ratios of video voltages or digitized light intensities, using 20 log of the ratio, even when the represented intensity (optical power) is directly proportional to the voltage generated by the sensor, not to its square, as in a CCD imager where response voltage is linear in intensity. Thus, a camera signal-to-noise ratio or dynamic range quoted as 40 dB represents a ratio of 100:1 between optical signal intensity and optical-equivalent dark-noise intensity, not a 10,000:1 intensity (power) ratio as 40 dB might suggest. Sometimes the 20 log ratio definition is applied to electron counts or photon counts directly, which are proportional to sensor signal amplitude without the need to consider whether the voltage response to intensity is linear.
However, as mentioned above, the 10 log intensity convention prevails more generally in physical optics, including fiber optics, so the terminology can become murky between the conventions of digital photographic technology and physics. Most commonly, quantities called "dynamic range" or "signal-to-noise" (of the camera) would be specified in 20 log dB, but in related contexts (e.g. attenuation, gain, intensifier SNR, or rejection ratio) the term should be interpreted cautiously, as confusion of the two units can result in very large misunderstandings of the value.
Photographers typically use an alternative base-2 log unit, the stop, to describe light intensity ratios or dynamic range.
Suffixes are commonly attached to the basic dB unit in order to indicate the reference value by which the ratio is calculated. For example, dBm indicates power measurement relative to 1 milliwatt.
In cases where the unit value of the reference is stated, the decibel value is known as "absolute". If the unit value of the reference is not explicitly stated, as in the dB gain of an amplifier, then the decibel value is considered relative.
This form of attaching suffixes to dB is widespread in practice, albeit being against the rules promulgated by standards bodies (ISO and IEC), given the "unacceptability of attaching information to units" and the "unacceptability of mixing information with units". The IEC 60027-3 standard recommends the following format: Lx (re xref) or as Lx/xref, where x is the quantity symbol and xref is the value of the reference quantity, e.g., LE (re 1 μV/m) = 20 dB or LE/(1 μV/m)= 20 dB for the electric field strength E relative to 1 μV/m reference value. If the measurement result 20 dB is presented separately, it can be specified using the information in parentheses, which is then part of the surrounding text and not a part of the unit: 20 dB (re: 1 μV/m) or 20 dB (1 μV/m).
Outside of documents adhering to SI units, the practice is very common as illustrated by the following examples. There is no general rule, with various discipline-specific practices. Sometimes the suffix is a unit symbol ("W","K","m"), sometimes it is a transliteration of a unit symbol ("uV" instead of μV for microvolt), sometimes it is an acronym for the unit's name ("sm" for square meter, "m" for milliwatt), other times it is a mnemonic for the type of quantity being calculated ("i" for antenna gain with respect to an isotropic antenna, "λ" for anything normalized by the EM wavelength), or otherwise a general attribute or identifier about the nature of the quantity ("A" for A-weighted sound pressure level). The suffix is often connected with a hyphen, as in "dB‑Hz", or with a space, as in "dB HL", or enclosed in parentheses, as in "dB(sm)", or with no intervening character, as in "dBm" (which is non-compliant with international standards).
Since the decibel is defined with respect to power, not amplitude, conversions of voltage ratios to decibels must square the amplitude, or use the factor of 20 instead of 10, as discussed above.
Probably the most common usage of "decibels" in reference to sound level is dB SPL, sound pressure level referenced to the nominal threshold of human hearing: The measures of pressure (a root-power quantity) use the factor of 20, and the measures of power (e.g. dB SIL and dB SWL) use the factor of 10.
See also dBV and dBu above. | [
{
"paragraph_id": 0,
"text": "The decibel (symbol: dB) is a relative unit of measurement equal to one tenth of a bel (B). It expresses the ratio of two values of a power or root-power quantity on a logarithmic scale. Two signals whose levels differ by one decibel have a power ratio of 10 (approximately 1.26) or root-power ratio of 10 (approximately 1.12).",
"title": ""
},
{
"paragraph_id": 1,
"text": "The unit expresses a relative change or an absolute value. In the latter case, the numeric value expresses the ratio of a value to a fixed reference value; when used in this way, the unit symbol is often suffixed with letter codes that indicate the reference value. For example, for the reference value of 1 volt, a common suffix is \"V\" (e.g., \"20 dBV\").",
"title": ""
},
{
"paragraph_id": 2,
"text": "Two principal types of scaling of the decibel are in common use. When expressing a power ratio, it is defined as ten times the logarithm in base 10. That is, a change in power by a factor of 10 corresponds to a 10 dB change in level. When expressing root-power quantities, a change in amplitude by a factor of 10 corresponds to a 20 dB change in level. The decibel scales differ by a factor of two, so that the related power and root-power levels change by the same value in linear systems, where power is proportional to the square of amplitude.",
"title": ""
},
{
"paragraph_id": 3,
"text": "The definition of the decibel originated in the measurement of transmission loss and power in telephony of the early 20th century in the Bell System in the United States. The bel was named in honor of Alexander Graham Bell, but the bel is seldom used. Instead, the decibel is used for a wide variety of measurements in science and engineering, most prominently in acoustics, electronics, and control theory. In electronics, the gains of amplifiers, attenuation of signals, and signal-to-noise ratios are often expressed in decibels.",
"title": ""
},
{
"paragraph_id": 4,
"text": "The decibel originates from methods used to quantify signal loss in telegraph and telephone circuits. Until the mid-1920s, the unit for loss was Miles of Standard Cable (MSC). 1 MSC corresponded to the loss of power over one mile (approximately 1.6 km) of standard telephone cable at a frequency of 5000 radians per second (795.8 Hz), and matched closely the smallest attenuation detectable to a listener. A standard telephone cable was \"a cable having uniformly distributed resistance of 88 ohms per loop-mile and uniformly distributed shunt capacitance of 0.054 microfarads per mile\" (approximately corresponding to 19 gauge wire).",
"title": "History"
},
{
"paragraph_id": 5,
"text": "In 1924, Bell Telephone Laboratories received a favorable response to a new unit definition among members of the International Advisory Committee on Long Distance Telephony in Europe and replaced the MSC with the Transmission Unit (TU). 1 TU was defined such that the number of TUs was ten times the base-10 logarithm of the ratio of measured power to a reference power. The definition was conveniently chosen such that 1 TU approximated 1 MSC; specifically, 1 MSC was 1.056 TU. In 1928, the Bell system renamed the TU into the decibel, being one tenth of a newly defined unit for the base-10 logarithm of the power ratio. It was named the bel, in honor of the telecommunications pioneer Alexander Graham Bell. The bel is seldom used, as the decibel was the proposed working unit.",
"title": "History"
},
{
"paragraph_id": 6,
"text": "The naming and early definition of the decibel is described in the NBS Standard's Yearbook of 1931:",
"title": "History"
},
{
"paragraph_id": 7,
"text": "Since the earliest days of the telephone, the need for a unit in which to measure the transmission efficiency of telephone facilities has been recognized. The introduction of cable in 1896 afforded a stable basis for a convenient unit and the \"mile of standard\" cable came into general use shortly thereafter. This unit was employed up to 1923 when a new unit was adopted as being more suitable for modern telephone work. The new transmission unit is widely used among the foreign telephone organizations and recently it was termed the \"decibel\" at the suggestion of the International Advisory Committee on Long Distance Telephony.",
"title": "History"
},
{
"paragraph_id": 8,
"text": "The decibel may be defined by the statement that two amounts of power differ by 1 decibel when they are in the ratio of 10 and any two amounts of power differ by N decibels when they are in the ratio of 10. The number of transmission units expressing the ratio of any two powers is therefore ten times the common logarithm of that ratio. This method of designating the gain or loss of power in telephone circuits permits direct addition or subtraction of the units expressing the efficiency of different parts of the circuit ...",
"title": "History"
},
{
"paragraph_id": 9,
"text": "In 1954, J. W. Horton argued that the use of the decibel as a unit for quantities other than transmission loss led to confusion, and suggested the name logit for \"standard magnitudes which combine by multiplication\", to contrast with the name unit for \"standard magnitudes which combine by addition\".",
"title": "History"
},
{
"paragraph_id": 10,
"text": "In April 2003, the International Committee for Weights and Measures (CIPM) considered a recommendation for the inclusion of the decibel in the International System of Units (SI), but decided against the proposal. However, the decibel is recognized by other international bodies such as the International Electrotechnical Commission (IEC) and International Organization for Standardization (ISO). The IEC permits the use of the decibel with root-power quantities as well as power and this recommendation is followed by many national standards bodies, such as NIST, which justifies the use of the decibel for voltage ratios. In spite of their widespread use, suffixes (such as in dBA or dBV) are not recognized by the IEC or ISO.",
"title": "History"
},
{
"paragraph_id": 11,
"text": "ISO 80000-3 describes definitions for quantities and units of space and time.",
"title": "Definition"
},
{
"paragraph_id": 12,
"text": "The IEC Standard 60027-3:2002 defines the following quantities. The decibel (dB) is one-tenth of a bel: 1 dB = 0.1 B. The bel (B) is 1⁄2 ln(10) nepers: 1 B = 1⁄2 ln(10) Np. The neper is the change in the level of a root-power quantity when the root-power quantity changes by a factor of e, that is 1 Np = ln(e) = 1, thereby relating all of the units as nondimensional natural log of root-power-quantity ratios, 1 dB = 0.115 13… Np = 0.115 13…. Finally, the level of a quantity is the logarithm of the ratio of the value of that quantity to a reference value of the same kind of quantity.",
"title": "Definition"
},
{
"paragraph_id": 13,
"text": "Therefore, the bel represents the logarithm of a ratio between two power quantities of 10:1, or the logarithm of a ratio between two root-power quantities of √10:1.",
"title": "Definition"
},
{
"paragraph_id": 14,
"text": "Two signals whose levels differ by one decibel have a power ratio of 10, which is approximately 1.25893, and an amplitude (root-power quantity) ratio of 10 (1.12202).",
"title": "Definition"
},
{
"paragraph_id": 15,
"text": "The bel is rarely used either without a prefix or with SI unit prefixes other than deci; it is preferred, for example, to use hundredths of a decibel rather than millibels. Thus, five one-thousandths of a bel would normally be written 0.05 dB, and not 5 mB.",
"title": "Definition"
},
{
"paragraph_id": 16,
"text": "The method of expressing a ratio as a level in decibels depends on whether the measured property is a power quantity or a root-power quantity; see Power, root-power, and field quantities for details.",
"title": "Definition"
},
{
"paragraph_id": 17,
"text": "When referring to measurements of power quantities, a ratio can be expressed as a level in decibels by evaluating ten times the base-10 logarithm of the ratio of the measured quantity to reference value. Thus, the ratio of P (measured power) to P0 (reference power) is represented by LP, that ratio expressed in decibels, which is calculated using the formula:",
"title": "Definition"
},
{
"paragraph_id": 18,
"text": "The base-10 logarithm of the ratio of the two power quantities is the number of bels. The number of decibels is ten times the number of bels (equivalently, a decibel is one-tenth of a bel). P and P0 must measure the same type of quantity, and have the same units before calculating the ratio. If P = P0 in the above equation, then LP = 0. If P is greater than P0 then LP is positive; if P is less than P0 then LP is negative.",
"title": "Definition"
},
{
"paragraph_id": 19,
"text": "Rearranging the above equation gives the following formula for P in terms of P0 and LP:",
"title": "Definition"
},
{
"paragraph_id": 20,
"text": "When referring to measurements of root-power quantities, it is usual to consider the ratio of the squares of F (measured) and F0 (reference). This is because the definitions were originally formulated to give the same value for relative ratios for both power and root-power quantities. Thus, the following definition is used:",
"title": "Definition"
},
{
"paragraph_id": 21,
"text": "The formula may be rearranged to give",
"title": "Definition"
},
{
"paragraph_id": 22,
"text": "Similarly, in electrical circuits, dissipated power is typically proportional to the square of voltage or current when the impedance is constant. Taking voltage as an example, this leads to the equation for power gain level LG:",
"title": "Definition"
},
{
"paragraph_id": 23,
"text": "where Vout is the root-mean-square (rms) output voltage, Vin is the rms input voltage. A similar formula holds for current.",
"title": "Definition"
},
{
"paragraph_id": 24,
"text": "The term root-power quantity is introduced by ISO Standard 80000-1:2009 as a substitute of field quantity. The term field quantity is deprecated by that standard and root-power is used throughout this article.",
"title": "Definition"
},
{
"paragraph_id": 25,
"text": "Although power and root-power quantities are different quantities, their respective levels are historically measured in the same units, typically decibels. A factor of 2 is introduced to make changes in the respective levels match under restricted conditions such as when the medium is linear and the same waveform is under consideration with changes in amplitude, or the medium impedance is linear and independent of both frequency and time. This relies on the relationship",
"title": "Definition"
},
{
"paragraph_id": 26,
"text": "holding. In a nonlinear system, this relationship does not hold by the definition of linearity. However, even in a linear system in which the power quantity is the product of two linearly related quantities (e.g. voltage and current), if the impedance is frequency- or time-dependent, this relationship does not hold in general, for example if the energy spectrum of the waveform changes.",
"title": "Definition"
},
{
"paragraph_id": 27,
"text": "For differences in level, the required relationship is relaxed from that above to one of proportionality (i.e., the reference quantities P0 and F0 need not be related), or equivalently,",
"title": "Definition"
},
{
"paragraph_id": 28,
"text": "must hold to allow the power level difference to be equal to the root-power level difference from power P1 and F1 to P2 and F2. An example might be an amplifier with unity voltage gain independent of load and frequency driving a load with a frequency-dependent impedance: the relative voltage gain of the amplifier is always 0 dB, but the power gain depends on the changing spectral composition of the waveform being amplified. Frequency-dependent impedances may be analyzed by considering the quantities power spectral density and the associated root-power quantities via the Fourier transform, which allows elimination of the frequency dependence in the analysis by analyzing the system at each frequency independently.",
"title": "Definition"
},
{
"paragraph_id": 29,
"text": "Since logarithm differences measured in these units often represent power ratios and root-power ratios, values for both are shown below. The bel is traditionally used as a unit of logarithmic power ratio, while the neper is used for logarithmic root-power (amplitude) ratio.",
"title": "Definition"
},
{
"paragraph_id": 30,
"text": "The unit dBW is often used to denote a ratio for which the reference is 1 W, and similarly dBm for a 1 mW reference point.",
"title": "Definition"
},
{
"paragraph_id": 31,
"text": "(31.62 V / 1 V) ≈ 1 kW / 1 W, illustrating the consequence from the definitions above that LG has the same value, 30 dB, regardless of whether it is obtained from powers or from amplitudes, provided that in the specific system being considered power ratios are equal to amplitude ratios squared.",
"title": "Definition"
},
{
"paragraph_id": 32,
"text": "A change in power ratio by a factor of 10 corresponds to a change in level of 10 dB. A change in power ratio by a factor of 2 or 1⁄2 is approximately a change of 3 dB. More precisely, the change is ±3.0103 dB, but this is almost universally rounded to 3 dB in technical writing. This implies an increase in voltage by a factor of √2 ≈ 1.4142. Likewise, a doubling or halving of the voltage, corresponding to a quadrupling or quartering of the power, is commonly described as 6 dB rather than ±6.0206 dB.",
"title": "Definition"
},
{
"paragraph_id": 33,
"text": "Should it be necessary to make the distinction, the number of decibels is written with additional significant figures. 3.000 dB corresponds to a power ratio of 10, or 1.9953, about 0.24% different from exactly 2, and a voltage ratio of 1.4125, 0.12% different from exactly √2. Similarly, an increase of 6.000 dB corresponds to the power ratio is 10 ≈ 3.9811, about 0.5% different from 4.",
"title": "Definition"
},
{
"paragraph_id": 34,
"text": "The decibel is useful for representing large ratios and for simplifying representation of multiplicative effects, such as attenuation from multiple sources along a signal chain. Its application in systems with additive effects is less intuitive, such as in the combined sound pressure level of two machines operating together. Care is also necessary with decibels directly in fractions and with the units of multiplicative operations.",
"title": "Properties"
},
{
"paragraph_id": 35,
"text": "The logarithmic scale nature of the decibel means that a very large range of ratios can be represented by a convenient number, in a manner similar to scientific notation. This allows one to clearly visualize huge changes of some quantity. See Bode plot and Semi-log plot. For example, 120 dB SPL may be clearer than \"a trillion times more intense than the threshold of hearing\".",
"title": "Properties"
},
{
"paragraph_id": 36,
"text": "Level values in decibels can be added instead of multiplying the underlying power values, which means that the overall gain of a multi-component system, such as a series of amplifier stages, can be calculated by summing the gains in decibels of the individual components, rather than multiply the amplification factors; that is, log(A × B × C) = log(A) + log(B) + log(C). Practically, this means that, armed only with the knowledge that 1 dB is a power gain of approximately 26%, 3 dB is approximately 2× power gain, and 10 dB is 10× power gain, it is possible to determine the power ratio of a system from the gain in dB with only simple addition and multiplication. For example:",
"title": "Properties"
},
{
"paragraph_id": 37,
"text": "However, according to its critics, the decibel creates confusion, obscures reasoning, is more related to the era of slide rules than to modern digital processing, and is cumbersome and difficult to interpret. Quantities in decibels are not necessarily additive, thus being \"of unacceptable form for use in dimensional analysis\". Thus, units require special care in decibel operations. Take, for example, carrier-to-noise-density ratio C/N0 (in hertz), involving carrier power C (in watts) and noise power spectral density N0 (in W/Hz). Expressed in decibels, this ratio would be a subtraction (C/N0)dB = CdB − N0dB. However, the linear-scale units still simplify in the implied fraction, so that the results would be expressed in dB-Hz.",
"title": "Properties"
},
{
"paragraph_id": 38,
"text": "According to Mitschke, \"The advantage of using a logarithmic measure is that in a transmission chain, there are many elements concatenated, and each has its own gain or attenuation. To obtain the total, addition of decibel values is much more convenient than multiplication of the individual factors.\" However, for the same reason that humans excel at additive operation over multiplication, decibels are awkward in inherently additive operations:",
"title": "Properties"
},
{
"paragraph_id": 39,
"text": "if two machines each individually produce a sound pressure level of, say, 90 dB at a certain point, then when both are operating together we should expect the combined sound pressure level to increase to 93 dB, but certainly not to 180 dB!; suppose that the noise from a machine is measured (including the contribution of background noise) and found to be 87 dBA but when the machine is switched off the background noise alone is measured as 83 dBA. [...] the machine noise [level (alone)] may be obtained by 'subtracting' the 83 dBA background noise from the combined level of 87 dBA; i.e., 84.8 dBA.; in order to find a representative value of the sound level in a room a number of measurements are taken at different positions within the room, and an average value is calculated. [...] Compare the logarithmic and arithmetic averages of [...] 70 dB and 90 dB: logarithmic average = 87 dB; arithmetic average = 80 dB.",
"title": "Properties"
},
{
"paragraph_id": 40,
"text": "Addition on a logarithmic scale is called logarithmic addition, and can be defined by taking exponentials to convert to a linear scale, adding there, and then taking logarithms to return. For example, where operations on decibels are logarithmic addition/subtraction and logarithmic multiplication/division, while operations on the linear scale are the usual operations:",
"title": "Properties"
},
{
"paragraph_id": 41,
"text": "The logarithmic mean is obtained from the logarithmic sum by subtracting 10 log 10 2 {\\displaystyle 10\\log _{10}2} , since logarithmic division is linear subtraction.",
"title": "Properties"
},
{
"paragraph_id": 42,
"text": "Attenuation constants, in topics such as optical fiber communication and radio propagation path loss, are often expressed as a fraction or ratio to distance of transmission. In this case, dB/m represents decibel per meter, dB/mi represents decibel per mile, for example. These quantities are to be manipulated obeying the rules of dimensional analysis, e.g., a 100-meter run with a 3.5 dB/km fiber yields a loss of 0.35 dB = 3.5 dB/km × 0.1 km.",
"title": "Properties"
},
{
"paragraph_id": 43,
"text": "The human perception of the intensity of sound and light more nearly approximates the logarithm of intensity rather than a linear relationship (see Weber–Fechner law), making the dB scale a useful measure.",
"title": "Uses"
},
{
"paragraph_id": 44,
"text": "The decibel is commonly used in acoustics as a unit of sound pressure level. The reference pressure for sound in air is set at the typical threshold of perception of an average human and there are common comparisons used to illustrate different levels of sound pressure. As sound pressure is a root-power quantity, the appropriate version of the unit definition is used:",
"title": "Uses"
},
{
"paragraph_id": 45,
"text": "where prms is the root mean square of the measured sound pressure and pref is the standard reference sound pressure of 20 micropascals in air or 1 micropascal in water.",
"title": "Uses"
},
{
"paragraph_id": 46,
"text": "Use of the decibel in underwater acoustics leads to confusion, in part because of this difference in reference value.",
"title": "Uses"
},
{
"paragraph_id": 47,
"text": "Sound intensity is proportional to the square of sound pressure. Therefore the sound intensity level can also be defined as:",
"title": "Uses"
},
{
"paragraph_id": 48,
"text": "The human ear has a large dynamic range in sound reception. The ratio of the sound intensity that causes permanent damage during short exposure to that of the quietest sound that the ear can hear is equal to or greater than 1 trillion (10). Such large measurement ranges are conveniently expressed in logarithmic scale: the base-10 logarithm of 10 is 12, which is expressed as a sound intensity level of 120 dB re 1 pW/m. The reference values of I and p in air have been chosen such that this also corresponds to a sound pressure level of 120 dB re 20 μPa.",
"title": "Uses"
},
{
"paragraph_id": 49,
"text": "Since the human ear is not equally sensitive to all sound frequencies, the acoustic power spectrum is modified by frequency weighting (A-weighting being the most common standard) to get the weighted acoustic power before converting to a sound level or noise level in decibels.",
"title": "Uses"
},
{
"paragraph_id": 50,
"text": "The decibel is used in telephony and audio. Similarly to the use in acoustics, a frequency weighted power is often used. For audio noise measurements in electrical circuits, the weightings are called psophometric weightings.",
"title": "Uses"
},
{
"paragraph_id": 51,
"text": "In electronics, the decibel is often used to express power or amplitude ratios (as for gains) in preference to arithmetic ratios or percentages. One advantage is that the total decibel gain of a series of components (such as amplifiers and attenuators) can be calculated simply by summing the decibel gains of the individual components. Similarly, in telecommunications, decibels denote signal gain or loss from a transmitter to a receiver through some medium (free space, waveguide, coaxial cable, fiber optics, etc.) using a link budget.",
"title": "Uses"
},
{
"paragraph_id": 52,
"text": "The decibel unit can also be combined with a reference level, often indicated via a suffix, to create an absolute unit of electric power. For example, it can be combined with \"m\" for \"milliwatt\" to produce the \"dBm\". A power level of 0 dBm corresponds to one milliwatt, and 1 dBm is one decibel greater (about 1.259 mW).",
"title": "Uses"
},
{
"paragraph_id": 53,
"text": "In professional audio specifications, a popular unit is the dBu. This is relative to the root mean square voltage which delivers 1 mW (0 dBm) into a 600-ohm resistor, or √1 mW×600 Ω ≈ 0.775 VRMS. When used in a 600-ohm circuit (historically, the standard reference impedance in telephone circuits), dBu and dBm are identical.",
"title": "Uses"
},
{
"paragraph_id": 54,
"text": "In an optical link, if a known amount of optical power, in dBm (referenced to 1 mW), is launched into a fiber, and the losses, in dB (decibels), of each component (e.g., connectors, splices, and lengths of fiber) are known, the overall link loss may be quickly calculated by addition and subtraction of decibel quantities.",
"title": "Uses"
},
{
"paragraph_id": 55,
"text": "In spectrometry and optics, the blocking unit used to measure optical density is equivalent to −1 B.",
"title": "Uses"
},
{
"paragraph_id": 56,
"text": "In connection with video and digital image sensors, decibels generally represent ratios of video voltages or digitized light intensities, using 20 log of the ratio, even when the represented intensity (optical power) is directly proportional to the voltage generated by the sensor, not to its square, as in a CCD imager where response voltage is linear in intensity. Thus, a camera signal-to-noise ratio or dynamic range quoted as 40 dB represents a ratio of 100:1 between optical signal intensity and optical-equivalent dark-noise intensity, not a 10,000:1 intensity (power) ratio as 40 dB might suggest. Sometimes the 20 log ratio definition is applied to electron counts or photon counts directly, which are proportional to sensor signal amplitude without the need to consider whether the voltage response to intensity is linear.",
"title": "Uses"
},
{
"paragraph_id": 57,
"text": "However, as mentioned above, the 10 log intensity convention prevails more generally in physical optics, including fiber optics, so the terminology can become murky between the conventions of digital photographic technology and physics. Most commonly, quantities called \"dynamic range\" or \"signal-to-noise\" (of the camera) would be specified in 20 log dB, but in related contexts (e.g. attenuation, gain, intensifier SNR, or rejection ratio) the term should be interpreted cautiously, as confusion of the two units can result in very large misunderstandings of the value.",
"title": "Uses"
},
{
"paragraph_id": 58,
"text": "Photographers typically use an alternative base-2 log unit, the stop, to describe light intensity ratios or dynamic range.",
"title": "Uses"
},
{
"paragraph_id": 59,
"text": "Suffixes are commonly attached to the basic dB unit in order to indicate the reference value by which the ratio is calculated. For example, dBm indicates power measurement relative to 1 milliwatt.",
"title": "Suffixes and reference values"
},
{
"paragraph_id": 60,
"text": "In cases where the unit value of the reference is stated, the decibel value is known as \"absolute\". If the unit value of the reference is not explicitly stated, as in the dB gain of an amplifier, then the decibel value is considered relative.",
"title": "Suffixes and reference values"
},
{
"paragraph_id": 61,
"text": "This form of attaching suffixes to dB is widespread in practice, albeit being against the rules promulgated by standards bodies (ISO and IEC), given the \"unacceptability of attaching information to units\" and the \"unacceptability of mixing information with units\". The IEC 60027-3 standard recommends the following format: Lx (re xref) or as Lx/xref, where x is the quantity symbol and xref is the value of the reference quantity, e.g., LE (re 1 μV/m) = 20 dB or LE/(1 μV/m)= 20 dB for the electric field strength E relative to 1 μV/m reference value. If the measurement result 20 dB is presented separately, it can be specified using the information in parentheses, which is then part of the surrounding text and not a part of the unit: 20 dB (re: 1 μV/m) or 20 dB (1 μV/m).",
"title": "Suffixes and reference values"
},
{
"paragraph_id": 62,
"text": "Outside of documents adhering to SI units, the practice is very common as illustrated by the following examples. There is no general rule, with various discipline-specific practices. Sometimes the suffix is a unit symbol (\"W\",\"K\",\"m\"), sometimes it is a transliteration of a unit symbol (\"uV\" instead of μV for microvolt), sometimes it is an acronym for the unit's name (\"sm\" for square meter, \"m\" for milliwatt), other times it is a mnemonic for the type of quantity being calculated (\"i\" for antenna gain with respect to an isotropic antenna, \"λ\" for anything normalized by the EM wavelength), or otherwise a general attribute or identifier about the nature of the quantity (\"A\" for A-weighted sound pressure level). The suffix is often connected with a hyphen, as in \"dB‑Hz\", or with a space, as in \"dB HL\", or enclosed in parentheses, as in \"dB(sm)\", or with no intervening character, as in \"dBm\" (which is non-compliant with international standards).",
"title": "Suffixes and reference values"
},
{
"paragraph_id": 63,
"text": "Since the decibel is defined with respect to power, not amplitude, conversions of voltage ratios to decibels must square the amplitude, or use the factor of 20 instead of 10, as discussed above.",
"title": "List of suffixes"
},
{
"paragraph_id": 64,
"text": "Probably the most common usage of \"decibels\" in reference to sound level is dB SPL, sound pressure level referenced to the nominal threshold of human hearing: The measures of pressure (a root-power quantity) use the factor of 20, and the measures of power (e.g. dB SIL and dB SWL) use the factor of 10.",
"title": "List of suffixes"
},
{
"paragraph_id": 65,
"text": "See also dBV and dBu above.",
"title": "List of suffixes"
}
] | The decibel is a relative unit of measurement equal to one tenth of a bel (B). It expresses the ratio of two values of a power or root-power quantity on a logarithmic scale. Two signals whose levels differ by one decibel have a power ratio of 101/10 or root-power ratio of 101⁄20. The unit expresses a relative change or an absolute value. In the latter case, the numeric value expresses the ratio of a value to a fixed reference value; when used in this way, the unit symbol is often suffixed with letter codes that indicate the reference value. For example, for the reference value of 1 volt, a common suffix is "V". Two principal types of scaling of the decibel are in common use. When expressing a power ratio, it is defined as ten times the logarithm in base 10. That is, a change in power by a factor of 10 corresponds to a 10 dB change in level. When expressing root-power quantities, a change in amplitude by a factor of 10 corresponds to a 20 dB change in level. The decibel scales differ by a factor of two, so that the related power and root-power levels change by the same value in linear systems, where power is proportional to the square of amplitude. The definition of the decibel originated in the measurement of transmission loss and power in telephony of the early 20th century in the Bell System in the United States. The bel was named in honor of Alexander Graham Bell, but the bel is seldom used. Instead, the decibel is used for a wide variety of measurements in science and engineering, most prominently in acoustics, electronics, and control theory. In electronics, the gains of amplifiers, attenuation of signals, and signal-to-noise ratios are often expressed in decibels. | 2001-10-01T18:18:50Z | 2023-11-29T00:32:13Z | [
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8,411 | Darwinism | Darwinism is a theory of biological evolution developed by the English naturalist Charles Darwin (1809–1882) and others, stating that all species of organisms arise and develop through the natural selection of small, inherited variations that increase the individual's ability to compete, survive, and reproduce. Also called Darwinian theory, it originally included the broad concepts of transmutation of species or of evolution which gained general scientific acceptance after Darwin published On the Origin of Species in 1859, including concepts which predated Darwin's theories. English biologist Thomas Henry Huxley coined the term Darwinism in April 1860.
Darwinism subsequently referred to the specific concepts of natural selection, the Weismann barrier, or the central dogma of molecular biology. Though the term usually refers strictly to biological evolution, creationists have appropriated it to refer to the origin of life or to cosmic evolution, that are distinct to biological evolution. It is therefore considered the belief and acceptance of Darwin's and of his predecessors' work, in place of other concepts, including divine design and extraterrestrial origins.
English biologist Thomas Henry Huxley coined the term Darwinism in April 1860. It was used to describe evolutionary concepts in general, including earlier concepts published by English philosopher Herbert Spencer. Many of the proponents of Darwinism at that time, including Huxley, had reservations about the significance of natural selection, and Darwin himself gave credence to what was later called Lamarckism. The strict neo-Darwinism of German evolutionary biologist August Weismann gained few supporters in the late 19th century. During the approximate period of the 1880s to about 1920, sometimes called "the eclipse of Darwinism", scientists proposed various alternative evolutionary mechanisms which eventually proved untenable. The development of the modern synthesis in the early 20th century, incorporating natural selection with population genetics and Mendelian genetics, revived Darwinism in an updated form.
While the term Darwinism has remained in use amongst the public when referring to modern evolutionary theory, it has increasingly been argued by science writers such as Olivia Judson, Eugenie Scott, and Carl Safina that it is an inappropriate term for modern evolutionary theory. For example, Darwin was unfamiliar with the work of the Moravian scientist and Augustinian friar Gregor Mendel, and as a result had only a vague and inaccurate understanding of heredity. He naturally had no inkling of later theoretical developments and, like Mendel himself, knew nothing of genetic drift, for example.
In the United States, creationists often use the term "Darwinism" as a pejorative term in reference to beliefs such as scientific materialism. This is now also the case even in the United Kingdom.
Huxley, upon first reading Darwin's theory in 1858, responded, "How extremely stupid not to have thought of that!"
While the term Darwinism had been used previously to refer to the work of Erasmus Darwin in the late 18th century, the term as understood today was introduced when Charles Darwin's 1859 book On the Origin of Species was reviewed by Thomas Henry Huxley in the April 1860 issue of the Westminster Review. Having hailed the book as "a veritable Whitworth gun in the armoury of liberalism" promoting scientific naturalism over theology, and praising the usefulness of Darwin's ideas while expressing professional reservations about Darwin's gradualism and doubting if it could be proved that natural selection could form new species, Huxley compared Darwin's achievement to that of Nicolaus Copernicus in explaining planetary motion:
What if the orbit of Darwinism should be a little too circular? What if species should offer residual phenomena, here and there, not explicable by natural selection? Twenty years hence naturalists may be in a position to say whether this is, or is not, the case; but in either event they will owe the author of "The Origin of Species" an immense debt of gratitude.... And viewed as a whole, we do not believe that, since the publication of Von Baer's "Researches on Development," thirty years ago, any work has appeared calculated to exert so large an influence, not only on the future of Biology, but in extending the domination of Science over regions of thought into which she has, as yet, hardly penetrated.
These are the basic tenets of evolution by natural selection as defined by Darwin:
Another important evolutionary theorist of the same period was the Russian geographer and prominent anarchist Pyotr Kropotkin who, in his book Mutual Aid: A Factor of Evolution (1902), advocated a conception of Darwinism counter to that of Huxley. His conception was centred around what he saw as the widespread use of co-operation as a survival mechanism in human societies and animals. He used biological and sociological arguments in an attempt to show that the main factor in facilitating evolution is cooperation between individuals in free-associated societies and groups. This was in order to counteract the conception of fierce competition as the core of evolution, which provided a rationalization for the dominant political, economic and social theories of the time; and the prevalent interpretations of Darwinism, such as those by Huxley, who is targeted as an opponent by Kropotkin. Kropotkin's conception of Darwinism could be summed up by the following quote:
In the animal world we have seen that the vast majority of species live in societies, and that they find in association the best arms for the struggle for life: understood, of course, in its wide Darwinian sense—not as a struggle for the sheer means of existence, but as a struggle against all natural conditions unfavourable to the species. The animal species, in which individual struggle has been reduced to its narrowest limits, and the practice of mutual aid has attained the greatest development, are invariably the most numerous, the most prosperous, and the most open to further progress. The mutual protection which is obtained in this case, the possibility of attaining old age and of accumulating experience, the higher intellectual development, and the further growth of sociable habits, secure the maintenance of the species, its extension, and its further progressive evolution. The unsociable species, on the contrary, are doomed to decay.
"Darwinism" soon came to stand for an entire range of evolutionary (and often revolutionary) philosophies about both biology and society. One of the more prominent approaches, summed in the 1864 phrase "survival of the fittest" by Herbert Spencer, later became emblematic of Darwinism even though Spencer's own understanding of evolution (as expressed in 1857) was more similar to that of Jean-Baptiste Lamarck than to that of Darwin, and predated the publication of Darwin's theory in 1859. What is now called "Social Darwinism" was, in its day, synonymous with "Darwinism"—the application of Darwinian principles of "struggle" to society, usually in support of anti-philanthropic political agenda. Another interpretation, one notably favoured by Darwin's half-cousin Francis Galton, was that "Darwinism" implied that because natural selection was apparently no longer working on "civilized" people, it was possible for "inferior" strains of people (who would normally be filtered out of the gene pool) to overwhelm the "superior" strains, and voluntary corrective measures would be desirable—the foundation of eugenics.
In Darwin's day there was no rigid definition of the term "Darwinism", and it was used by opponents and proponents of Darwin's biological theory alike to mean whatever they wanted it to in a larger context. The ideas had international influence, and Ernst Haeckel developed what was known as Darwinismus in Germany, although, like Spencer's "evolution", Haeckel's "Darwinism" had only a rough resemblance to the theory of Charles Darwin, and was not centred on natural selection. In 1886, Alfred Russel Wallace went on a lecture tour across the United States, starting in New York and going via Boston, Washington, Kansas, Iowa and Nebraska to California, lecturing on what he called "Darwinism" without any problems.
In his book Darwinism (1889), Wallace had used the term pure-Darwinism which proposed a "greater efficacy" for natural selection. George Romanes dubbed this view as "Wallaceism", noting that in contrast to Darwin, this position was advocating a "pure theory of natural selection to the exclusion of any supplementary theory." Taking influence from Darwin, Romanes was a proponent of both natural selection and the inheritance of acquired characteristics. The latter was denied by Wallace who was a strict selectionist. Romanes' definition of Darwinism conformed directly with Darwin's views and was contrasted with Wallace's definition of the term.
The term Darwinism is often used in the United States by promoters of creationism, notably by leading members of the intelligent design movement, as an epithet to attack evolution as though it were an ideology (an "ism") based on philosophical naturalism, atheism, or both. For example, in 1993, UC Berkeley law professor and author Phillip E. Johnson made this accusation of atheism with reference to Charles Hodge's 1874 book What Is Darwinism?. However, unlike Johnson, Hodge confined the term to exclude those like American botanist Asa Gray who combined Christian faith with support for Darwin's natural selection theory, before answering the question posed in the book's title by concluding: "It is Atheism."
Creationists use pejoratively the term Darwinism to imply that the theory has been held as true only by Darwin and a core group of his followers, whom they cast as dogmatic and inflexible in their belief. In the 2008 documentary film Expelled: No Intelligence Allowed, which promotes intelligent design (ID), American writer and actor Ben Stein refers to scientists as Darwinists. Reviewing the film for Scientific American, John Rennie says "The term is a curious throwback, because in modern biology almost no one relies solely on Darwin's original ideas... Yet the choice of terminology isn't random: Ben Stein wants you to stop thinking of evolution as an actual science supported by verifiable facts and logical arguments and to start thinking of it as a dogmatic, atheistic ideology akin to Marxism."
However, Darwinism is also used neutrally within the scientific community to distinguish the modern evolutionary synthesis, which is sometimes called "neo-Darwinism", from those first proposed by Darwin. Darwinism also is used neutrally by historians to differentiate his theory from other evolutionary theories current around the same period. For example, Darwinism may refer to Darwin's proposed mechanism of natural selection, in comparison to more recent mechanisms such as genetic drift and gene flow. It may also refer specifically to the role of Charles Darwin as opposed to others in the history of evolutionary thought—particularly contrasting Darwin's results with those of earlier theories such as Lamarckism or later ones such as the modern evolutionary synthesis.
In political discussions in the United States, the term is mostly used by its enemies. "It's a rhetorical device to make evolution seem like a kind of faith, like 'Maoism,'" says Harvard University biologist E. O. Wilson. He adds, "Scientists don't call it 'Darwinism'." In the United Kingdom, the term often retains its positive sense as a reference to natural selection, and for example British ethologist and evolutionary biologist Richard Dawkins wrote in his collection of essays A Devil's Chaplain, published in 2003, that as a scientist he is a Darwinist.
In his 1995 book Darwinian Fairytales, Australian philosopher David Stove used the term "Darwinism" in a different sense than the above examples. Describing himself as non-religious and as accepting the concept of natural selection as a well-established fact, Stove nonetheless attacked what he described as flawed concepts proposed by some "Ultra-Darwinists." Stove alleged that by using weak or false ad hoc reasoning, these Ultra-Darwinists used evolutionary concepts to offer explanations that were not valid: for example, Stove suggested that the sociobiological explanation of altruism as an evolutionary feature was presented in such a way that the argument was effectively immune to any criticism. English philosopher Simon Blackburn wrote a rejoinder to Stove, though a subsequent essay by Stove's protégé James Franklin suggested that Blackburn's response actually "confirms Stove's central thesis that Darwinism can 'explain' anything."
In more recent times, the Australian moral philosopher and professor Peter Singer, who serves as the Ira W. DeCamp Professor of Bioethics at Princeton University, has proposed the development of a "Darwinian left" based on the contemporary scientific understanding of biological anthropology, human evolution, and applied ethics in order to achieve the establishment of a more equal and cooperative human society in accordance with the sociobiological explanation of altruism.
In evolutionary aesthetics theory, there is evidence that perceptions of beauty are determined by natural selection and therefore Darwinian; that things, aspects of people and landscapes considered beautiful are typically found in situations likely to give enhanced survival of the perceiving human's genes.
Evolutionary biology portal | [
{
"paragraph_id": 0,
"text": "Darwinism is a theory of biological evolution developed by the English naturalist Charles Darwin (1809–1882) and others, stating that all species of organisms arise and develop through the natural selection of small, inherited variations that increase the individual's ability to compete, survive, and reproduce. Also called Darwinian theory, it originally included the broad concepts of transmutation of species or of evolution which gained general scientific acceptance after Darwin published On the Origin of Species in 1859, including concepts which predated Darwin's theories. English biologist Thomas Henry Huxley coined the term Darwinism in April 1860.",
"title": ""
},
{
"paragraph_id": 1,
"text": "Darwinism subsequently referred to the specific concepts of natural selection, the Weismann barrier, or the central dogma of molecular biology. Though the term usually refers strictly to biological evolution, creationists have appropriated it to refer to the origin of life or to cosmic evolution, that are distinct to biological evolution. It is therefore considered the belief and acceptance of Darwin's and of his predecessors' work, in place of other concepts, including divine design and extraterrestrial origins.",
"title": "Terminology"
},
{
"paragraph_id": 2,
"text": "English biologist Thomas Henry Huxley coined the term Darwinism in April 1860. It was used to describe evolutionary concepts in general, including earlier concepts published by English philosopher Herbert Spencer. Many of the proponents of Darwinism at that time, including Huxley, had reservations about the significance of natural selection, and Darwin himself gave credence to what was later called Lamarckism. The strict neo-Darwinism of German evolutionary biologist August Weismann gained few supporters in the late 19th century. During the approximate period of the 1880s to about 1920, sometimes called \"the eclipse of Darwinism\", scientists proposed various alternative evolutionary mechanisms which eventually proved untenable. The development of the modern synthesis in the early 20th century, incorporating natural selection with population genetics and Mendelian genetics, revived Darwinism in an updated form.",
"title": "Terminology"
},
{
"paragraph_id": 3,
"text": "While the term Darwinism has remained in use amongst the public when referring to modern evolutionary theory, it has increasingly been argued by science writers such as Olivia Judson, Eugenie Scott, and Carl Safina that it is an inappropriate term for modern evolutionary theory. For example, Darwin was unfamiliar with the work of the Moravian scientist and Augustinian friar Gregor Mendel, and as a result had only a vague and inaccurate understanding of heredity. He naturally had no inkling of later theoretical developments and, like Mendel himself, knew nothing of genetic drift, for example.",
"title": "Terminology"
},
{
"paragraph_id": 4,
"text": "In the United States, creationists often use the term \"Darwinism\" as a pejorative term in reference to beliefs such as scientific materialism. This is now also the case even in the United Kingdom.",
"title": "Terminology"
},
{
"paragraph_id": 5,
"text": "Huxley, upon first reading Darwin's theory in 1858, responded, \"How extremely stupid not to have thought of that!\"",
"title": "Huxley and Kropotkin"
},
{
"paragraph_id": 6,
"text": "While the term Darwinism had been used previously to refer to the work of Erasmus Darwin in the late 18th century, the term as understood today was introduced when Charles Darwin's 1859 book On the Origin of Species was reviewed by Thomas Henry Huxley in the April 1860 issue of the Westminster Review. Having hailed the book as \"a veritable Whitworth gun in the armoury of liberalism\" promoting scientific naturalism over theology, and praising the usefulness of Darwin's ideas while expressing professional reservations about Darwin's gradualism and doubting if it could be proved that natural selection could form new species, Huxley compared Darwin's achievement to that of Nicolaus Copernicus in explaining planetary motion:",
"title": "Huxley and Kropotkin"
},
{
"paragraph_id": 7,
"text": "What if the orbit of Darwinism should be a little too circular? What if species should offer residual phenomena, here and there, not explicable by natural selection? Twenty years hence naturalists may be in a position to say whether this is, or is not, the case; but in either event they will owe the author of \"The Origin of Species\" an immense debt of gratitude.... And viewed as a whole, we do not believe that, since the publication of Von Baer's \"Researches on Development,\" thirty years ago, any work has appeared calculated to exert so large an influence, not only on the future of Biology, but in extending the domination of Science over regions of thought into which she has, as yet, hardly penetrated.",
"title": "Huxley and Kropotkin"
},
{
"paragraph_id": 8,
"text": "These are the basic tenets of evolution by natural selection as defined by Darwin:",
"title": "Huxley and Kropotkin"
},
{
"paragraph_id": 9,
"text": "Another important evolutionary theorist of the same period was the Russian geographer and prominent anarchist Pyotr Kropotkin who, in his book Mutual Aid: A Factor of Evolution (1902), advocated a conception of Darwinism counter to that of Huxley. His conception was centred around what he saw as the widespread use of co-operation as a survival mechanism in human societies and animals. He used biological and sociological arguments in an attempt to show that the main factor in facilitating evolution is cooperation between individuals in free-associated societies and groups. This was in order to counteract the conception of fierce competition as the core of evolution, which provided a rationalization for the dominant political, economic and social theories of the time; and the prevalent interpretations of Darwinism, such as those by Huxley, who is targeted as an opponent by Kropotkin. Kropotkin's conception of Darwinism could be summed up by the following quote:",
"title": "Huxley and Kropotkin"
},
{
"paragraph_id": 10,
"text": "In the animal world we have seen that the vast majority of species live in societies, and that they find in association the best arms for the struggle for life: understood, of course, in its wide Darwinian sense—not as a struggle for the sheer means of existence, but as a struggle against all natural conditions unfavourable to the species. The animal species, in which individual struggle has been reduced to its narrowest limits, and the practice of mutual aid has attained the greatest development, are invariably the most numerous, the most prosperous, and the most open to further progress. The mutual protection which is obtained in this case, the possibility of attaining old age and of accumulating experience, the higher intellectual development, and the further growth of sociable habits, secure the maintenance of the species, its extension, and its further progressive evolution. The unsociable species, on the contrary, are doomed to decay.",
"title": "Huxley and Kropotkin"
},
{
"paragraph_id": 11,
"text": "\"Darwinism\" soon came to stand for an entire range of evolutionary (and often revolutionary) philosophies about both biology and society. One of the more prominent approaches, summed in the 1864 phrase \"survival of the fittest\" by Herbert Spencer, later became emblematic of Darwinism even though Spencer's own understanding of evolution (as expressed in 1857) was more similar to that of Jean-Baptiste Lamarck than to that of Darwin, and predated the publication of Darwin's theory in 1859. What is now called \"Social Darwinism\" was, in its day, synonymous with \"Darwinism\"—the application of Darwinian principles of \"struggle\" to society, usually in support of anti-philanthropic political agenda. Another interpretation, one notably favoured by Darwin's half-cousin Francis Galton, was that \"Darwinism\" implied that because natural selection was apparently no longer working on \"civilized\" people, it was possible for \"inferior\" strains of people (who would normally be filtered out of the gene pool) to overwhelm the \"superior\" strains, and voluntary corrective measures would be desirable—the foundation of eugenics.",
"title": "Other 19th-century usage"
},
{
"paragraph_id": 12,
"text": "In Darwin's day there was no rigid definition of the term \"Darwinism\", and it was used by opponents and proponents of Darwin's biological theory alike to mean whatever they wanted it to in a larger context. The ideas had international influence, and Ernst Haeckel developed what was known as Darwinismus in Germany, although, like Spencer's \"evolution\", Haeckel's \"Darwinism\" had only a rough resemblance to the theory of Charles Darwin, and was not centred on natural selection. In 1886, Alfred Russel Wallace went on a lecture tour across the United States, starting in New York and going via Boston, Washington, Kansas, Iowa and Nebraska to California, lecturing on what he called \"Darwinism\" without any problems.",
"title": "Other 19th-century usage"
},
{
"paragraph_id": 13,
"text": "In his book Darwinism (1889), Wallace had used the term pure-Darwinism which proposed a \"greater efficacy\" for natural selection. George Romanes dubbed this view as \"Wallaceism\", noting that in contrast to Darwin, this position was advocating a \"pure theory of natural selection to the exclusion of any supplementary theory.\" Taking influence from Darwin, Romanes was a proponent of both natural selection and the inheritance of acquired characteristics. The latter was denied by Wallace who was a strict selectionist. Romanes' definition of Darwinism conformed directly with Darwin's views and was contrasted with Wallace's definition of the term.",
"title": "Other 19th-century usage"
},
{
"paragraph_id": 14,
"text": "The term Darwinism is often used in the United States by promoters of creationism, notably by leading members of the intelligent design movement, as an epithet to attack evolution as though it were an ideology (an \"ism\") based on philosophical naturalism, atheism, or both. For example, in 1993, UC Berkeley law professor and author Phillip E. Johnson made this accusation of atheism with reference to Charles Hodge's 1874 book What Is Darwinism?. However, unlike Johnson, Hodge confined the term to exclude those like American botanist Asa Gray who combined Christian faith with support for Darwin's natural selection theory, before answering the question posed in the book's title by concluding: \"It is Atheism.\"",
"title": "Contemporary usage"
},
{
"paragraph_id": 15,
"text": "Creationists use pejoratively the term Darwinism to imply that the theory has been held as true only by Darwin and a core group of his followers, whom they cast as dogmatic and inflexible in their belief. In the 2008 documentary film Expelled: No Intelligence Allowed, which promotes intelligent design (ID), American writer and actor Ben Stein refers to scientists as Darwinists. Reviewing the film for Scientific American, John Rennie says \"The term is a curious throwback, because in modern biology almost no one relies solely on Darwin's original ideas... Yet the choice of terminology isn't random: Ben Stein wants you to stop thinking of evolution as an actual science supported by verifiable facts and logical arguments and to start thinking of it as a dogmatic, atheistic ideology akin to Marxism.\"",
"title": "Contemporary usage"
},
{
"paragraph_id": 16,
"text": "However, Darwinism is also used neutrally within the scientific community to distinguish the modern evolutionary synthesis, which is sometimes called \"neo-Darwinism\", from those first proposed by Darwin. Darwinism also is used neutrally by historians to differentiate his theory from other evolutionary theories current around the same period. For example, Darwinism may refer to Darwin's proposed mechanism of natural selection, in comparison to more recent mechanisms such as genetic drift and gene flow. It may also refer specifically to the role of Charles Darwin as opposed to others in the history of evolutionary thought—particularly contrasting Darwin's results with those of earlier theories such as Lamarckism or later ones such as the modern evolutionary synthesis.",
"title": "Contemporary usage"
},
{
"paragraph_id": 17,
"text": "In political discussions in the United States, the term is mostly used by its enemies. \"It's a rhetorical device to make evolution seem like a kind of faith, like 'Maoism,'\" says Harvard University biologist E. O. Wilson. He adds, \"Scientists don't call it 'Darwinism'.\" In the United Kingdom, the term often retains its positive sense as a reference to natural selection, and for example British ethologist and evolutionary biologist Richard Dawkins wrote in his collection of essays A Devil's Chaplain, published in 2003, that as a scientist he is a Darwinist.",
"title": "Contemporary usage"
},
{
"paragraph_id": 18,
"text": "In his 1995 book Darwinian Fairytales, Australian philosopher David Stove used the term \"Darwinism\" in a different sense than the above examples. Describing himself as non-religious and as accepting the concept of natural selection as a well-established fact, Stove nonetheless attacked what he described as flawed concepts proposed by some \"Ultra-Darwinists.\" Stove alleged that by using weak or false ad hoc reasoning, these Ultra-Darwinists used evolutionary concepts to offer explanations that were not valid: for example, Stove suggested that the sociobiological explanation of altruism as an evolutionary feature was presented in such a way that the argument was effectively immune to any criticism. English philosopher Simon Blackburn wrote a rejoinder to Stove, though a subsequent essay by Stove's protégé James Franklin suggested that Blackburn's response actually \"confirms Stove's central thesis that Darwinism can 'explain' anything.\"",
"title": "Contemporary usage"
},
{
"paragraph_id": 19,
"text": "In more recent times, the Australian moral philosopher and professor Peter Singer, who serves as the Ira W. DeCamp Professor of Bioethics at Princeton University, has proposed the development of a \"Darwinian left\" based on the contemporary scientific understanding of biological anthropology, human evolution, and applied ethics in order to achieve the establishment of a more equal and cooperative human society in accordance with the sociobiological explanation of altruism.",
"title": "Contemporary usage"
},
{
"paragraph_id": 20,
"text": "In evolutionary aesthetics theory, there is evidence that perceptions of beauty are determined by natural selection and therefore Darwinian; that things, aspects of people and landscapes considered beautiful are typically found in situations likely to give enhanced survival of the perceiving human's genes.",
"title": "Esoteric usage"
},
{
"paragraph_id": 21,
"text": "Evolutionary biology portal",
"title": "See also"
},
{
"paragraph_id": 22,
"text": "",
"title": "External links"
}
] | Darwinism is a theory of biological evolution developed by the English naturalist Charles Darwin (1809–1882) and others, stating that all species of organisms arise and develop through the natural selection of small, inherited variations that increase the individual's ability to compete, survive, and reproduce. Also called Darwinian theory, it originally included the broad concepts of transmutation of species or of evolution which gained general scientific acceptance after Darwin published On the Origin of Species in 1859, including concepts which predated Darwin's theories. English biologist Thomas Henry Huxley coined the term Darwinism in April 1860. | 2001-09-08T21:53:33Z | 2023-12-28T00:54:55Z | [
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8,412 | Doraemon | Doraemon (ドラえもん) is a Japanese manga series written and illustrated by Fujiko F. Fujio. The manga was first serialized in December 1969. Its chapters were collected in 45 tankōbon volumes published by Shogakukan from 1974 to 1996. The story revolves around an earless robotic cat named Doraemon, who travels back in time from the 22nd century to aid a boy named Nobita Nobi.
The manga spawned a media franchise. Three anime TV series have been adapted in 1973, 1979, and 2005. Additionally, Shin-Ei Animation has produced over forty animated films, including two 3D computer-animated films, all of which are distributed by Toho. Various types of merchandise and media have been developed, including soundtrack albums, video games, and musicals. The manga series was licensed for an English language release in North America, via Amazon Kindle, by a collaboration of Fujiko F. Fujio Pro with Voyager Japan and AltJapan Co., Ltd. The anime series was licensed by Disney for an English-language release in North America in 2014, and LUK International in Europe, the Middle East and Africa.
Doraemon was well-received by critics and became a hit in many Asian countries. It won numerous awards, including the Japan Cartoonists Association Award in 1973 and 1994, the Shogakukan Manga Award for children's manga in 1982, and the Tezuka Osamu Cultural Prize in 1997. By 2019, it has sold over 250 million copies worldwide, becoming one of the best-selling manga series in history. The Doraemon character has been viewed as a Japanese cultural icon, and was appointed as the first "anime ambassador" in 2008 by the country's Foreign Ministry.
Nobita Nobi is a ten-year-old Japanese school boy, who is kind-hearted and honest, but also lazy, unlucky, weak, gets bad grades and is bad at sports. One day, a robot cat from the 22nd century named Doraemon is sent back to the past by Nobita's future grandchild, Sewashi Nobi, to take care of Nobita so that his descendants can have a better life. Doraemon has a four-dimensional pouch in which he stores tools, inventions, and gadgets from the future to aid Nobita whenever he is faced with a problem. Although Doraemon is a cat robot, he has a fear of mice because of an incident where robotic mice chewed off his ears. This is why Doraemon lost his original yellow color and turned blue, from sadness.
Nobita has three main friends: Takeshi Goda (nicknamed Gian), Suneo Honekawa (Gian's sidekick), and Shizuka Minamoto, Nobita's best friend and love-interest. Gian is a strong, leading and domineering boy, but also loyal to his friends. Suneo is a wealthy and spoiled boy who uses his friendship with Gian to win the respect of other schoolmates. Shizuka is a gentle and kind girl who frequently plays with Nobita. Nobita has a crush on Shizuka; she is his prospective future wife (Nobita's future wife is initially Gian's younger sister). Although Gian and Suneo are Nobita's friends, they also typically bully and abuse him. Nobita normally responds by using Doraemon's gadgets to fight back against them, but Nobita has a tendency to get carried away with using the gadgets (or Gian and Suneo, if they steal it away), which typically results in unintended consequences for him and others.
In addition to Gian, Suneo, and Shizuka, Dorami and Hidetoshi Dekisugi are also recurring characters. Dorami is Doraemon's younger sister, and Dekisugi is a gifted student boy who as Shizuka's close friend, frequently attracts the jealousy of Nobita.
Doraemon is written and illustrated by Fujiko F. Fujio, the pen name of Japanese manga artist Hiroshi Fujimoto. According to Fujio, it was originally conceived following a series of three events: when searching for ideas for a new manga, he wished a machine existed that would come up with ideas for him, he tripped over his daughter's toy, and heard cats fighting in his neighborhood. To set up the plot and characters, he inspired some elements from his earlier manga series, Obake no Q-Tarō, which involve an obake living with humans, with a similar formula. Fujio said that the idea for Doraemon came after "an accumulation of trial and error", during which he finally found the most suitable style of manga to him. Initially, the series achieved little success as gekiga was well-known at the time, and only became a hit after its adaptation into an anime TV series and multiple feature films.
Doraemon is mainly aimed at children, so Fujio chose to create the character with a simple graphic style, based on shapes such as circles and ellipses. He used the same sequences of cartoons with regularity and continuity to enhance the reader's ease of understanding. In addition, blue, a characteristic color of Doraemon, was chosen as the main color in magazine publications, which used to have a yellow cover and red title. Set in Tokyo, the manga reflected parts of Japan's society, such as the class system and the "ideal" of Japanese childhood. Problems, if occur, were resolved in a way so as not to rely on violence and eroticism, and the stories were integrated with the concept of environmentalism. The manga also insisted on the ethical values of integrity, perseverance, courage, family and respect.
In order to underline the crucial role of the young generation in society, the manga's creator chose to have the act carried out in a "children's domain" where young people can live with happiness, freedom and power without adult's interference. As Saya S. Shiraishi noted, the existence of the "domain" helped Doraemon to have a strong appeal in various Asian countries. During Doraemon's development, Fujio did not express a change in characters; he said, "When a manga hero become a success, the manga suddenly stops being interesting. So the hero has to be like the stripes on a barber pole; he seems to keep moving upward, but actually he stays in the same place."
According to Zensho Ito, Fujio's former student, the "length" of time in the universe is one of the ideas that inspired Fujio to make Doraemon. Frequently displayed in its stories is Nobita's desire to control time, and there exist time-control gadgets that he uses to satisfy that desire, particularly the "Time Machine", which lies in his desk drawer. Unlike Western works on science fiction, the manga did not explain the theory nor the applied technology behind these tools, but instead focusing on how the characters exploit their advantages, making it more children-friendly.
The name "Doraemon" can be roughly translated to "stray". Unusually, the name "Doraemon" (ドラえもん) is written in a mixture of two Japanese scripts: Katakana (ドラ) and Hiragana (えもん). "Dora" derives from "dora neko" (どら猫, stray cat), and is a corruption of nora (stray), while "-emon" (in kanji 右衛門) is an old-fashioned suffix for male names (for example, as in Ishikawa Goemon). Nobita's home address in Tsukimidai ("moon-view-heights"), Nerima refers to Fujimidai ("Fuji-view-heights"), where Osamu Tezuka's residence and animation studio is based. The name "Nobita Nobi" refers to "nobi nobi", meaning "the way a young child grows up free, healthy, and happy, unrestrained in any sense".
Gadgets, or "himitsu dōgu" (ひみつ道具), are Doraemon's tools from the future, usually used to help the characters. Fujio said that Doraemon has a total of 1,293 gadgets; according to a 2004 analysis by Yasuyuki Yokoyama of Toyama University, there are 1,963 gadgets found in 1,344 sketches. The most important gadgets include "Take-Copter", a small piece of headgear made out of bamboo that can allow its users to fly; "Time Machine", a machine used for time travel; "Anywhere Door", a pink-colored door that allows people to travel according to the thoughts of the person who turns the knob; "Time Kerchief", a handkerchief which can turn an object new or old or a person young or old; "Translator Tool", a cuboid jelly that allow one to converse in any language; and "Designer", a camera used to instantly dress-up the user.
Saya S. Shiraishi wrote that most of the gadgets were "an impressive testimony to the standards of quality control and innovation that exist in the twenty-second century". The gadgets were an essential part of the series so as to reflect a positive point of view about the association of technology in children, and to express the wishes of modern society.
The series stopped publishing after Fujimoto's death in 1996, without an ending; this has aroused numerous urban legends throughout the years. One of the most well-known "endings" of the manga was by an amateur manga cartoonist under the pen name "Yasue T. Tajima", first appeared on the Internet in 1998 and made up into a manga in 2005. The story takes place when Doraemon's battery dies, and Nobita later grows up becoming a robot engineer, potentially revive Doraemon and live a happy life. Tajima issued an apology in 2007, and the profits were shared with Shogakukan and the copyright owner, Fujiko F. Fujio Pro.
Ryūichi Yagi and Takashi Yamazaki, the directors of Stand by Me Doraemon, confirmed that it had only one opening, while the ending has been rewritten several times. Because of this, Shogakukan had to clarify that only if the marriage of Nobita and Shizuka is finalized will the mission be accomplished, and then Doraemon will return to the future.
In December 1969, the Doraemon manga appeared in six different children's monthly magazines published by Shogakukan: Yoiko, Yōchien, Shogaku Ichi-nensei, Shogaku Ni-nensei, Shogaku San-nensei, and Shogaku Yo-nensei. The magazines were aimed at children from nursery school to fourth grade. In 1973, two other magazines, Shogaku Go-nensei and Shogaku Roku-nensei (aimed at fifth-grade and sixth-grade students respectively), started publishing the manga. In 1977, CoroCoro Comic was launched as the flagship magazine of Doraemon.
Since the debut of Doraemon in 1969, the stories have been selectively collected into forty-five tankōbon volumes that were published under Shogakukan's Tentōmushi Comics (てんとう虫コミックス) imprint from July 31, 1974, to April 26, 1996. These volumes are collected in the Takaoka Central Library in Toyama, Japan, where Fujio was born. Between April 25, 2005, and February 28, 2006, Shōgakukan published a series of five manga volumes under the title Doraemon Plus (Doraemon+), featuring short stories which did not appear in the forty-five original volumes; a sixth volume, the first volume in eight years, was published on December 1, 2014. Additionally, 119 unpublished stories were compiled into six colored-manga volumes under the title Doraemon Kara Sakuhin-shu (ドラえもん カラー作品集, Doraemon Color Works), published from July 17, 1999, to September 2, 2006. Between July 24, 2009, and September 25, 2012, Shogakukan published a master works collection consisting of twenty volumes with all 1,345 stories written by Fujio. In December 2019, on the 50th anniversary of Doraemon, a "Volume 0" was published by Shogakukan featuring six different versions of Doraemon's first appearance.
There have been two series of bilingual, Japanese and English, volumes of the manga by Shogakukan English Comics under the title Doraemon: Gadget Cat from the Future, and two audio versions. The first series has ten volumes and the second one has six. 21st Century Publishing House released bilingual English-Chinese versions in Mainland China, and Chingwin Publishing Group released bilingual English-Chinese versions in Taiwan.
In July 2013, Fujiko F. Fujio Pro announced that they would be collaborating with ebook publisher Voyager Japan and localization company AltJapan Co., Ltd. to release an English-language version of the manga in full color digitally via the Amazon Kindle platform in North America. Shogakukan released the first volume in November 2013; by 2016, a total of 200 volumes have been published. This English version incorporates a variety of changes to character names; Nobita is "Noby", Shizuka is "Sue", Suneo is "Sneech", and Gian is "Big G", while dorayaki is "Yummy Bun/Fudgy Pudgy Pie". Also, by 2016, four volumes of the manga have been published in English in print by Shogakukan Asia.
Shogakukan started digital distribution of all forty-five original volumes throughout Japan from July 16, 2015.
Doraemon Long Stories is the core of the work, as is Doraemon Short Stories. Doraemon Long Stories is a manga and movie series ongoing since 1979, featuring longer and continuous narratives about the characters' adventures into various lands of science fiction and fantasy. Long Stories manga series consists of twenty-four tankōbon volumes published from 1983 to 2004.
Several spin-off manga series of Doraemon have been made. The Doraemons, a manga illustrated by Michiaki Tanaka based on Doraemon, was published by Shogakukan in six tankōbon volumes from 1996 to 2001. Between 1997 and 2003, Shogakukan also published fifteen volumes of The Doraemons Special, created by Yukihiro Mitani and Masaru Miyazaki as a complement part of The Doraemons, including twelve from the main series and three from the Robot Training School Edition. Dorabase, a baseball-themed manga written and illustrated by Mugiwara Shintarō, is another spin-off of Doraemon; twenty-three volumes of the manga were published by Shogakukan from April 26, 2001, to October 28, 2011.
The first attempt of a Doraemon animated series was in 1973, by Nippon Television. After a January 1973 pilot named Doraemon Mirai Kara Yattekuru (ドラえもんが未来からやってくる, Doraemon Coming from the Future), twenty-six episodes, each with two segments, were broadcast on Nippon TV from April 1 to September 30 of the same year. The series was directed by Mitsuo Kaminashi with voice cast from Aoni Production; the character Doraemon was voiced by Kōsei Tomita, then later by Masako Nozawa. Later in the series, the animation studio, Nippon TeleMovie Productions, went bankrupt, and the masters were sold off or destroyed. The series was re-aired on Nippon TV and several local stations until 1979, when Shogakukan requested Toyama Television to cease broadcasting. Some of the segments were found in the archives of Imagica in 1995, and some others were recovered by Jun Masami in 2003. As of 2013, 21 of 52 segments are known to survive, two of which have no audio.
Doraemon remained fairly exclusive in manga form until 1979 when a animation studio, Shin-Ei Animation (now owned by TV Asahi) produced an animated second attempt of Doraemon. The series aired on TV Asahi from April 2, 1979. Ryo Motohira served as chief director from 1981, and Tsutomu Shibayama from 1984. Eiichi Nakamura served as director of character designer, while Shunsuke Kikuchi was the composer. Nobuyo Ōyama voiced Doraemon in the series; because of this, in Asia, this version is sometimes referred to as the Ōyama Edition. In total, 1,787 episodes were produced and released in VHS and DVD by Toho. On April 15, 2005, a major renewal was carried out, including the replacement of voice actors and staff, and updated character designs (Doraemon (2005 TV series)). The third series is sometimes referred to in Asia as the Mizuta Edition, as a tribute for the voice actress for Doraemon, Wasabi Mizuta. It was released in DVD on February 10, 2006 under the title New TV-ban Doraemon (NEW TV 版 ドラえもん, Doraemon NEW TV Version) with Shogakukan Video banner.
In May 2014, TV Asahi Corporation announced an agreement with The Walt Disney Company to bring the 2005 series to the Disney XD television channel and Disney Channel in the United States beginning in the summer of that year. Besides using the name changes that were used in AltJapan's English adaptation of the original manga, other changes and edits have also been made to make the show more relatable to an American audience, such as Japanese text being replaced with English text on certain objects like signs and graded papers, items such as yen notes being replaced by US dollar bills, and the setting being changed from Japan to the United States. Initial response to the edited dub was positive. The Disney adaptation began broadcast in Japan on Disney Channel from February 1, 2016. The broadcast offered the choice of the English voice track or a newly recorded Japanese track by the Japanese cast of the 2005 series.
The anime has also been aired in over sixty countries worldwide. It premiered in Thailand in 1982, the Philippines in 1999, India in 2005, and Vietnam in 2010. Other Asian countries that broadcast the series include China, Hong Kong, Singapore, Taiwan, Malaysia, Indonesia, and South Korea. The series is licensed in EMEA regions by LUK International; it premiered in Spain in 1993 and France in 2003. It has also been distributed in South American countries, including Brazil, Colombia, and Chile. In 2017, POPS Worldwide, a Vietnamese multimedia company, collaborated with TV Asahi to release the anime series on YouTube and other digital platforms.
By 2023, there have been 42 annual feature-length animated films produced by Shin-Ei Animation and released by Toho. The first twenty-five films are based on the 1979 anime, while the rest are based on the 2005 anime. Unlike the anime and manga series, the films are more action-adventure oriented, taking the familiar characters of Doraemon and placing them in a variety of exotic and perilous settings.
A 3D computer animated film, Stand by Me Doraemon, debuted in Japan on August 8, 2014. Directed by Takashi Yamazaki and Ryūichi Yagi, it combines elements from the short stories of the manga series: "All the Way from the Country of the Future", "Imprinting Egg", "Goodbye, Shizuka-chan", "Romance in Snowy Mountain", "Nobita's the Night Before a Wedding", and "Goodbye, Doraemon ..." into a new complete story, from the first time Doraemon came to Nobita's house to Doraemon bidding farewell to Nobita. The film was a box office success, grossing $183.4 million worldwide. A sequel, Stand by Me Doraemon 2, also directed by Yamazaki and Yagi, was released on November 20, 2020.
Several Doraemon short films were produced and released between 1989 and 2004. These include 2112: The Birth of Doraemon, a film about the life of Doraemon from birth before coming to Nobita; Doraemon: Nobita's the Night Before a Wedding, a film about the events related to the marriage of Nobita and Shizuka; The Day When I Was Born and Doraemon: A Grandmother's Recollections, the films about the relationship between Nobita and his parents along with his grandmother. Other short films focus on Dorami and The Doraemons. In 1981, Toho released What Am I for Momotaro, a film about Momotarō, the hero of Japanese folklore.
In 1994, an educational OVA was made, titled Doraemon: Nobita to Mirai Note (ドラえもん のび太と未来ノート), where the main characters express the hope for a better Earth. The OVA was released in DVD along with the 13th issue of Fujiko F. Fujio Wonderland magazine in September 2004. A crossover episode of Doraemon with AIBOU: Tokyo Detective Duo aired on TV Asahi on November 9, 2018.
The soundtrack of the 1973 anime series was composed by Nobuyoshi Koshibe, who also arranged the opening theme song "Doraemon" (ドラえもん) and the ending theme song "Doraemon Rumba" (ドラえもん ルンバ), both performed by Harumi Naitō. For the 1979 anime, Shunsuke Kikuchi was the composer, who arranged "Doraemon no Uta" (ドラえもんのうた); it had been performed by numerous singers, including Kumiko Ōsugi and Satoko Yamano. When the anime got a reboot in 2005, Kan Sawada was the composer of the series. There are four other opening themes, including an instrumental version of "Doraemon no Uta" performed by Twelve Girls Band; "Hagushichao" (ハグしちゃお) performed by Rimi Natsukawa; "Yume wo Kanaete Doraemon" (夢をかなえてドラえもん), the opening theme broadcast from 2007 to 2018; and "Doraemon" performed by Gen Hoshino, broadcast since October 2019.
Numerous collections of theme songs of the anime series and feature films were initially available in cassettes. Since the 1990s, Doraemon songs have been released in CD, under the type of singles and compilation albums. Soundtracks of Doraemon feature films have been released by Nippon Columbia since 2001 in the album series "Doraemon Soundtrack History" (ドラえもんサウンドトラックヒストリー).
Doraemon has been adapted into a musical, titled Doraemon the Musical: Nobita and the Animal Planet (舞台版ドラえもん のび太とアニマル惑星, Butaiban Doraemon: Nobita to Animaru Puranetto). Based on the 1990 anime film of the same name, it debuted at Tokyo Metropolitan Art Space on September 4, 2008, running through September 14. Shoji Kokami was the director and writer, Makoto Sakamoto played Nobita and Reiko Suho as Shizuka; Jaian and Suneo were portrayed by Tomohiro Waki and Kensaku Kobayashi, respectively; Wasabi Mizuta voiced Doraemon. The musical was later revived and ran at Sunshine Theater, Tokyo from March 26 to April 2, 2017, then later in other prefectures including Fukuoka, Osaka, Miyagi and Aichi. The 2017 revival is also directed and written by Kokami, with Mizuta reprising her role; Nobita, Shizuka, Jaian and Suneo were played by Yuuchi Ogoe, Hina Higuchi, Koki Azuma and Shō Jinnai, respectively.
Many Japanese-only video games based on Doraemon have been developed. For instance, in 1983, Bandai developed Dokodemo Dorayaki Doraemon (どこでも ドラヤキ ドラえもん), an arcade game inspired by Pac-Man. Doraemon, a NES video game made by Hudson Soft, was released on December 12, 1986, and became one of the best-selling games of that year in Japan with over 1.15 million copies sold. On December 6, 2007, Sega published Doraemon Wii, the first Doraemon video game released on Wii. Doraemon can also be seen in Namco's Taiko no Tatsujin rhythm game series, such as in Taiko no Tatsujin: Sesson de Dodon ga Don! (2017). The first Doraemon game to receive a Western release was Doraemon Story of Seasons (2019). Card games with Doraemon themes have also been made in several special occasions, sometimes to exploit the popularity of feature films. In 2016, a special edition of Uno about the series' characters was released exclusively in Japan, as a result of a cooperation between Asatsu-DK and Mattel.
In Japan, the Doraemon merchandising rights belong to Shogakukan-Shueisha Productions, which has produced and distributed a wide range of products under its brand, such as toys, food, stationery, action figures, gashapon, shoes, clothing, and others. Several companies have collaborated on the creation and distribution of products on the series and its characters, including Sanrio, Converse, Moleskine, and ESP Guitars, which has made guitars decorated with Doraemon characters; a further partnership of Doraemon with Uniqlo led to a line of clothing designed by Takashi Murakami. The Doraemon franchise has also collaborated with various Japanese brands, including Tsi Groove & Sports's Jack Bunny!! golf apparel brand, Unicharm's MamiPoko diaper brand, and the video games LINE Pop 2, Monster Strike, and Granblue Fantasy. Viz Media owns the Doraemon merchandising rights in North and Latin America, which has developed Doraemon-themed clothing and collectibles in collaboration with retail chain Hot Topic, and themed Happy Meals in a 2015 collaboration with McDonald's. Viz Media Europe (now Crunchyroll EMEA) manages the merchandising in Europe except Spain and Portugal; LUK International has obtained licenses in these two countries.
Characters from Doraemon have been used in advertising through specific agreements with Shogakukan. For instance, following the Cool Japan initiative promoted by the Japanese government, Sharp Corporation produced a series of commercials featuring the characters of Doraemon and Nobita, which were broadcast in several ASEAN countries. In late 2011, Shogakukan and Toyota Motor Corporation joined forces to create a series of live-action commercials as part of Toyota's ReBorn ad campaign, which depicted the manga's characters two decades after being grown up, where Hollywood actor Jean Reno played Doraemon.
Doraemon is considered one of the best-known manga of all time, a true Japanese cultural icon, and an essential part of family life of the Japanese post-war generation. Akihiro Motoyama observed that "mothers who watched the movies when they were children are now taking their own children to see them". It was also commercially successful: over 108 million books were sold in Japan by 1996. The 1979 and 2005 anime series also achieved high ratings on television. With the film Doraemon: Nobita's Secret Gadget Museum, the Doraemon anime film series reached 100 million tickets sold at the Japanese box office, surpassing Godzilla as the highest-grossing film franchise in Japan. By 2015, it had sold over 103 million tickets, and was the largest franchise by numbers of admissions in the country.
Doraemon was also a hit in Asia in general, and was considered one of the typical cases of Japanese soft power, although it was published without a license in some countries. The anime television series is available in over 60 countries, and reportedly getting high ratings in at least 30 countries. However, Doraemon was less successful in Western countries, because it was viewed as a children-only series, and there were some tight restrictions about publishing manga and broadcasting anime series there. The manga has sold over 170 million copies worldwide by 2012, and 250 million by 2019. Estimates show that Doraemon has generated at least more than $4.3 billion in merchandise sales by 2019, and over $1.7 billion from anime feature films by 2020, making it one of the highest-grossing media franchises of all time.
Outside Japan, Doraemon achieved particular success in Vietnam, with a record-breaking 40 million copies sold by 2006. The manga was first launched there in 1992 by Kim Đồng Publishing House, but the copyright from Shogakukan was not fully acquired until 1996. In 1993, the Vietnamese Ministry of Culture considered the manga's publication to be "an impactful event for the improvement of children, youth and adult's likings ... [Doraemon] is a comprehensively educational book series which has the effect of developing children's personality". Doraemon is now a cultural icon in Vietnam, having featured in many cultural events.
Doraemon received favorable reviews. Mark Schilling wrote, "For kids whose lives are often so regulated, Doraemon represents a welcome breath of freedom and a glimpse of a funnier, friendlier world where all dreams, even foolish ones, can come true." Italian writer Massimo Nicora wrote that the manga "can be interpreted as a type of book that criticizes, with irony, the omnipotence of science that pretends to solve every problem with its tools", alluding to the fact that Doraemon's gadgets often end up making the problems even worse than they initially were, more than anything else. He added that it represents "the metaphor of the childish imagination, which always manages to find the most bizarre and original solutions, in a continuous game of transformation of reality".
Some critics considered that Nobita's flawed personality and modest background is different from the special or extraordinary characteristics usually seen in other typical anime and manga protagonists; this portrayal has been seen as reasons of its appeal as well as the contrary, especially in the United States. According to the Italian Parents Movement (Moige), in the manga, "the lazy Nobita does not know any kind of appreciable evolution", though there are still good points including "the criticism of bullying, the goodness that transpires from the little Nobita and the positive figure of Shizuka".
In his 2000 article, Leo Ching explained that the success of Doraemon in Asia was because it had reflected the Asian values such as imagination and responsibility, the same reason that Oshin, another Japanese cultural export, became well-known there. On the other hand, according to an analysis by Anne Allison, professor of cultural anthropology at Duke University, the strong point of it was not the variety of the gadgets, but the relationship between Doraemon and Nobita, which was particularly appreciated. Jason Thompson praised the "silly situations" and "old fashioned, simple artwork", with Doraemon's expression and comments adding to the "surrounding elementary-school mischief". On the manga's 50th anniversary, an op-ed published on Asahi Shimbun stated that the manga "has already become a contemporary classic".
Doraemon has received numerous accolades. It won the Japan Cartoonists Association Award twice in 1973 and 1994, the former for Excellence Award while the latter for Minister of Education, Science and Technology Award. In 1982, it received the first Shogakukan Manga Award for children's manga. In 1997, the manga won the Grand Prize at the first Tezuka Osamu Cultural Prize. The 1979 series won the award from the Japanese Agency for Cultural Affairs four times for best television series in 1984, 1985, 1988 and 1989.
A 2006 poll among 80,000 Japanese fans for the 10th anniversary of the Japan Media Arts Festival placed Doraemon at fifth among the top ten best manga of all time. The 2005 and 2006 surveys conducted by TV Asahi found the Doraemon anime ranked fifth and third, respectively, among the 100 most favorite anime series of all time. In 2010, a survey conducted by researchers of Tokyo Polytechnic University found that most responders considered Doraemon, along with Dragon Ball franchise, to be the anime series that represents Cool Japan. In a 2013 survey, Doraemon was found to be the best anime recommended for foreign people.
Doraemon has been blamed for having a negative impact on children, due to the controversial traits of the characters in the anime. The character has received criticism in China, where some media outlets considered Doraemon to be a politically subversive character and that it was a tool of Japan's "cultural invasion". In 2016, a resolution to ban Hindi dubbed Doraemon anime series was submitted in Pakistan. Around the same time, legal notices were served against several companies in India, targeting Doraemon and Crayon Shin-chan for bans (which did not materialize), as having an adverse effect on children. Disney Channel India, the regional broadcaster of the anime, was banned in Bangladesh and Pakistan citing non-availability of localized dubs for content including Doraemon.
The Doraemon manga has inspired many other mangakas; these include Eiichiro Oda, the creator of One Piece with the idea of "Devil Fruits", and Masashi Kishimoto, the creator of Naruto, who showed interest in drawing characters from anime shows during his childhood, including Doraemon. The manga has also been mentioned in Gin Tama and Great Teacher Onizuka. The character Doraemon is considered one of the cultural icons in Japan, and one of the most well-known characters in manga history; some critics compared his notability with Mickey Mouse and Snoopy. Mark Schilling noted that Doraemon's "Take-Copter" is familiar among Japanese people "just as Snoopy's biplane is familiar to most Americans".
On April 22, 2002, on the special issue of Asian Hero in Time magazine, Doraemon was the only anime character to be named one of the twenty-two Asian Heroes, and was described as "The Cuddliest Hero in Asia". A 2007 poll by Oricon shown that Doraemon was the second-strongest manga character ever, behind only Son Goku of Dragon Ball. Doraemon is also referred as something with the ability to satisfy all wishes.
In 2005, the Taiwan Society of New York selected Doraemon as a culturally significant work of Japanese otaku pop-culture in its exhibit Little Boy: The Arts of Japan's Exploding Subculture, curated by renowned artist Takashi Murakami. In 2008, the Japanese Ministry of Foreign Affairs appointed Doraemon as the first anime cultural ambassador; a Ministry spokesperson explained the decision as an attempt to help people in other countries understand Japanese anime better and to deepen their interest in Japanese culture. On September 3, 2012, Doraemon was granted official residence in the city of Kawasaki, Kanagawa, one hundred years before he was born. In the same year, Hong Kong celebrated the birthday of Doraemon 100 years early with a series of displays of the character. In April 2013, Doraemon was chosen as Japan's ambassador in Tokyo's bid to host the 2020 Summer Olympics and 2020 Summer Paralympics. He appeared in the 2016 Summer Olympics closing ceremony to promote the 2020 Summer Olympics in Tokyo.
A Fujiko F. Fujio museum opened in Kawasaki on September 3, 2011, featuring Doraemon as the star of the museum. The National Museum of Singapore held a time-travelling exhibition in October 2020 as a tribute to the manga. After the 2011 Tōhoku earthquake and tsunami, Shogakukan released an earthquake survival guidebook, which included the main cast of the Doraemon manga series. TV Asahi launched the Doraemon Fund charity fund to raise money for natural disasters in 2004, and in 2011. In 2020, Mumbai's Sion Friends Circle group distributed food and books to kids using mascots, one being Doraemon, to help during the COVID-19 pandemic. In Vietnam, a Doraemon scholarship fund was established in 1996, and the Doraemon character has been used for education of traffic safety. Doraemon's creator, Fujiko F. Fujio, received the Culture Fighter Medal from the Vietnamese Ministry of Culture in 1996 for his contributions to young education through the manga.
Many prominent figures have been nicknamed after the cast of Doraemon: politician Osamu Fujimura is known as the "Doraemon of Nagatacho" due to his figure and warm personality, and sumo wrestler Takamisugi was nicknamed "Doraemon" because of his resemblance to the character. In 2015, a group of people in a drought-affected village in northern Thailand used a Doraemon toy to complete a rain-ritual, in order to avoid controversies that would occur by using real animals.
A parody of Doraemon created by Hikari Fujisaki, titled Nozoemon (のぞえもん), was first serialized in Nihon Bungeisha's Comic Heaven magazine in September 2014, with the compiled book volume released on June 9, 2015; however, it was discontinued in August 2015 due to content issues. | [
{
"paragraph_id": 0,
"text": "Doraemon (ドラえもん) is a Japanese manga series written and illustrated by Fujiko F. Fujio. The manga was first serialized in December 1969. Its chapters were collected in 45 tankōbon volumes published by Shogakukan from 1974 to 1996. The story revolves around an earless robotic cat named Doraemon, who travels back in time from the 22nd century to aid a boy named Nobita Nobi.",
"title": ""
},
{
"paragraph_id": 1,
"text": "The manga spawned a media franchise. Three anime TV series have been adapted in 1973, 1979, and 2005. Additionally, Shin-Ei Animation has produced over forty animated films, including two 3D computer-animated films, all of which are distributed by Toho. Various types of merchandise and media have been developed, including soundtrack albums, video games, and musicals. The manga series was licensed for an English language release in North America, via Amazon Kindle, by a collaboration of Fujiko F. Fujio Pro with Voyager Japan and AltJapan Co., Ltd. The anime series was licensed by Disney for an English-language release in North America in 2014, and LUK International in Europe, the Middle East and Africa.",
"title": ""
},
{
"paragraph_id": 2,
"text": "Doraemon was well-received by critics and became a hit in many Asian countries. It won numerous awards, including the Japan Cartoonists Association Award in 1973 and 1994, the Shogakukan Manga Award for children's manga in 1982, and the Tezuka Osamu Cultural Prize in 1997. By 2019, it has sold over 250 million copies worldwide, becoming one of the best-selling manga series in history. The Doraemon character has been viewed as a Japanese cultural icon, and was appointed as the first \"anime ambassador\" in 2008 by the country's Foreign Ministry.",
"title": ""
},
{
"paragraph_id": 3,
"text": "Nobita Nobi is a ten-year-old Japanese school boy, who is kind-hearted and honest, but also lazy, unlucky, weak, gets bad grades and is bad at sports. One day, a robot cat from the 22nd century named Doraemon is sent back to the past by Nobita's future grandchild, Sewashi Nobi, to take care of Nobita so that his descendants can have a better life. Doraemon has a four-dimensional pouch in which he stores tools, inventions, and gadgets from the future to aid Nobita whenever he is faced with a problem. Although Doraemon is a cat robot, he has a fear of mice because of an incident where robotic mice chewed off his ears. This is why Doraemon lost his original yellow color and turned blue, from sadness.",
"title": "Synopsis"
},
{
"paragraph_id": 4,
"text": "Nobita has three main friends: Takeshi Goda (nicknamed Gian), Suneo Honekawa (Gian's sidekick), and Shizuka Minamoto, Nobita's best friend and love-interest. Gian is a strong, leading and domineering boy, but also loyal to his friends. Suneo is a wealthy and spoiled boy who uses his friendship with Gian to win the respect of other schoolmates. Shizuka is a gentle and kind girl who frequently plays with Nobita. Nobita has a crush on Shizuka; she is his prospective future wife (Nobita's future wife is initially Gian's younger sister). Although Gian and Suneo are Nobita's friends, they also typically bully and abuse him. Nobita normally responds by using Doraemon's gadgets to fight back against them, but Nobita has a tendency to get carried away with using the gadgets (or Gian and Suneo, if they steal it away), which typically results in unintended consequences for him and others.",
"title": "Synopsis"
},
{
"paragraph_id": 5,
"text": "In addition to Gian, Suneo, and Shizuka, Dorami and Hidetoshi Dekisugi are also recurring characters. Dorami is Doraemon's younger sister, and Dekisugi is a gifted student boy who as Shizuka's close friend, frequently attracts the jealousy of Nobita.",
"title": "Synopsis"
},
{
"paragraph_id": 6,
"text": "Doraemon is written and illustrated by Fujiko F. Fujio, the pen name of Japanese manga artist Hiroshi Fujimoto. According to Fujio, it was originally conceived following a series of three events: when searching for ideas for a new manga, he wished a machine existed that would come up with ideas for him, he tripped over his daughter's toy, and heard cats fighting in his neighborhood. To set up the plot and characters, he inspired some elements from his earlier manga series, Obake no Q-Tarō, which involve an obake living with humans, with a similar formula. Fujio said that the idea for Doraemon came after \"an accumulation of trial and error\", during which he finally found the most suitable style of manga to him. Initially, the series achieved little success as gekiga was well-known at the time, and only became a hit after its adaptation into an anime TV series and multiple feature films.",
"title": "Creation and conception"
},
{
"paragraph_id": 7,
"text": "Doraemon is mainly aimed at children, so Fujio chose to create the character with a simple graphic style, based on shapes such as circles and ellipses. He used the same sequences of cartoons with regularity and continuity to enhance the reader's ease of understanding. In addition, blue, a characteristic color of Doraemon, was chosen as the main color in magazine publications, which used to have a yellow cover and red title. Set in Tokyo, the manga reflected parts of Japan's society, such as the class system and the \"ideal\" of Japanese childhood. Problems, if occur, were resolved in a way so as not to rely on violence and eroticism, and the stories were integrated with the concept of environmentalism. The manga also insisted on the ethical values of integrity, perseverance, courage, family and respect.",
"title": "Creation and conception"
},
{
"paragraph_id": 8,
"text": "In order to underline the crucial role of the young generation in society, the manga's creator chose to have the act carried out in a \"children's domain\" where young people can live with happiness, freedom and power without adult's interference. As Saya S. Shiraishi noted, the existence of the \"domain\" helped Doraemon to have a strong appeal in various Asian countries. During Doraemon's development, Fujio did not express a change in characters; he said, \"When a manga hero become a success, the manga suddenly stops being interesting. So the hero has to be like the stripes on a barber pole; he seems to keep moving upward, but actually he stays in the same place.\"",
"title": "Creation and conception"
},
{
"paragraph_id": 9,
"text": "According to Zensho Ito, Fujio's former student, the \"length\" of time in the universe is one of the ideas that inspired Fujio to make Doraemon. Frequently displayed in its stories is Nobita's desire to control time, and there exist time-control gadgets that he uses to satisfy that desire, particularly the \"Time Machine\", which lies in his desk drawer. Unlike Western works on science fiction, the manga did not explain the theory nor the applied technology behind these tools, but instead focusing on how the characters exploit their advantages, making it more children-friendly.",
"title": "Creation and conception"
},
{
"paragraph_id": 10,
"text": "The name \"Doraemon\" can be roughly translated to \"stray\". Unusually, the name \"Doraemon\" (ドラえもん) is written in a mixture of two Japanese scripts: Katakana (ドラ) and Hiragana (えもん). \"Dora\" derives from \"dora neko\" (どら猫, stray cat), and is a corruption of nora (stray), while \"-emon\" (in kanji 右衛門) is an old-fashioned suffix for male names (for example, as in Ishikawa Goemon). Nobita's home address in Tsukimidai (\"moon-view-heights\"), Nerima refers to Fujimidai (\"Fuji-view-heights\"), where Osamu Tezuka's residence and animation studio is based. The name \"Nobita Nobi\" refers to \"nobi nobi\", meaning \"the way a young child grows up free, healthy, and happy, unrestrained in any sense\".",
"title": "Creation and conception"
},
{
"paragraph_id": 11,
"text": "Gadgets, or \"himitsu dōgu\" (ひみつ道具), are Doraemon's tools from the future, usually used to help the characters. Fujio said that Doraemon has a total of 1,293 gadgets; according to a 2004 analysis by Yasuyuki Yokoyama of Toyama University, there are 1,963 gadgets found in 1,344 sketches. The most important gadgets include \"Take-Copter\", a small piece of headgear made out of bamboo that can allow its users to fly; \"Time Machine\", a machine used for time travel; \"Anywhere Door\", a pink-colored door that allows people to travel according to the thoughts of the person who turns the knob; \"Time Kerchief\", a handkerchief which can turn an object new or old or a person young or old; \"Translator Tool\", a cuboid jelly that allow one to converse in any language; and \"Designer\", a camera used to instantly dress-up the user.",
"title": "Creation and conception"
},
{
"paragraph_id": 12,
"text": "Saya S. Shiraishi wrote that most of the gadgets were \"an impressive testimony to the standards of quality control and innovation that exist in the twenty-second century\". The gadgets were an essential part of the series so as to reflect a positive point of view about the association of technology in children, and to express the wishes of modern society.",
"title": "Creation and conception"
},
{
"paragraph_id": 13,
"text": "The series stopped publishing after Fujimoto's death in 1996, without an ending; this has aroused numerous urban legends throughout the years. One of the most well-known \"endings\" of the manga was by an amateur manga cartoonist under the pen name \"Yasue T. Tajima\", first appeared on the Internet in 1998 and made up into a manga in 2005. The story takes place when Doraemon's battery dies, and Nobita later grows up becoming a robot engineer, potentially revive Doraemon and live a happy life. Tajima issued an apology in 2007, and the profits were shared with Shogakukan and the copyright owner, Fujiko F. Fujio Pro.",
"title": "Creation and conception"
},
{
"paragraph_id": 14,
"text": "Ryūichi Yagi and Takashi Yamazaki, the directors of Stand by Me Doraemon, confirmed that it had only one opening, while the ending has been rewritten several times. Because of this, Shogakukan had to clarify that only if the marriage of Nobita and Shizuka is finalized will the mission be accomplished, and then Doraemon will return to the future.",
"title": "Creation and conception"
},
{
"paragraph_id": 15,
"text": "In December 1969, the Doraemon manga appeared in six different children's monthly magazines published by Shogakukan: Yoiko, Yōchien, Shogaku Ichi-nensei, Shogaku Ni-nensei, Shogaku San-nensei, and Shogaku Yo-nensei. The magazines were aimed at children from nursery school to fourth grade. In 1973, two other magazines, Shogaku Go-nensei and Shogaku Roku-nensei (aimed at fifth-grade and sixth-grade students respectively), started publishing the manga. In 1977, CoroCoro Comic was launched as the flagship magazine of Doraemon.",
"title": "Media"
},
{
"paragraph_id": 16,
"text": "Since the debut of Doraemon in 1969, the stories have been selectively collected into forty-five tankōbon volumes that were published under Shogakukan's Tentōmushi Comics (てんとう虫コミックス) imprint from July 31, 1974, to April 26, 1996. These volumes are collected in the Takaoka Central Library in Toyama, Japan, where Fujio was born. Between April 25, 2005, and February 28, 2006, Shōgakukan published a series of five manga volumes under the title Doraemon Plus (Doraemon+), featuring short stories which did not appear in the forty-five original volumes; a sixth volume, the first volume in eight years, was published on December 1, 2014. Additionally, 119 unpublished stories were compiled into six colored-manga volumes under the title Doraemon Kara Sakuhin-shu (ドラえもん カラー作品集, Doraemon Color Works), published from July 17, 1999, to September 2, 2006. Between July 24, 2009, and September 25, 2012, Shogakukan published a master works collection consisting of twenty volumes with all 1,345 stories written by Fujio. In December 2019, on the 50th anniversary of Doraemon, a \"Volume 0\" was published by Shogakukan featuring six different versions of Doraemon's first appearance.",
"title": "Media"
},
{
"paragraph_id": 17,
"text": "There have been two series of bilingual, Japanese and English, volumes of the manga by Shogakukan English Comics under the title Doraemon: Gadget Cat from the Future, and two audio versions. The first series has ten volumes and the second one has six. 21st Century Publishing House released bilingual English-Chinese versions in Mainland China, and Chingwin Publishing Group released bilingual English-Chinese versions in Taiwan.",
"title": "Media"
},
{
"paragraph_id": 18,
"text": "In July 2013, Fujiko F. Fujio Pro announced that they would be collaborating with ebook publisher Voyager Japan and localization company AltJapan Co., Ltd. to release an English-language version of the manga in full color digitally via the Amazon Kindle platform in North America. Shogakukan released the first volume in November 2013; by 2016, a total of 200 volumes have been published. This English version incorporates a variety of changes to character names; Nobita is \"Noby\", Shizuka is \"Sue\", Suneo is \"Sneech\", and Gian is \"Big G\", while dorayaki is \"Yummy Bun/Fudgy Pudgy Pie\". Also, by 2016, four volumes of the manga have been published in English in print by Shogakukan Asia.",
"title": "Media"
},
{
"paragraph_id": 19,
"text": "Shogakukan started digital distribution of all forty-five original volumes throughout Japan from July 16, 2015.",
"title": "Media"
},
{
"paragraph_id": 20,
"text": "Doraemon Long Stories is the core of the work, as is Doraemon Short Stories. Doraemon Long Stories is a manga and movie series ongoing since 1979, featuring longer and continuous narratives about the characters' adventures into various lands of science fiction and fantasy. Long Stories manga series consists of twenty-four tankōbon volumes published from 1983 to 2004.",
"title": "Media"
},
{
"paragraph_id": 21,
"text": "Several spin-off manga series of Doraemon have been made. The Doraemons, a manga illustrated by Michiaki Tanaka based on Doraemon, was published by Shogakukan in six tankōbon volumes from 1996 to 2001. Between 1997 and 2003, Shogakukan also published fifteen volumes of The Doraemons Special, created by Yukihiro Mitani and Masaru Miyazaki as a complement part of The Doraemons, including twelve from the main series and three from the Robot Training School Edition. Dorabase, a baseball-themed manga written and illustrated by Mugiwara Shintarō, is another spin-off of Doraemon; twenty-three volumes of the manga were published by Shogakukan from April 26, 2001, to October 28, 2011.",
"title": "Media"
},
{
"paragraph_id": 22,
"text": "The first attempt of a Doraemon animated series was in 1973, by Nippon Television. After a January 1973 pilot named Doraemon Mirai Kara Yattekuru (ドラえもんが未来からやってくる, Doraemon Coming from the Future), twenty-six episodes, each with two segments, were broadcast on Nippon TV from April 1 to September 30 of the same year. The series was directed by Mitsuo Kaminashi with voice cast from Aoni Production; the character Doraemon was voiced by Kōsei Tomita, then later by Masako Nozawa. Later in the series, the animation studio, Nippon TeleMovie Productions, went bankrupt, and the masters were sold off or destroyed. The series was re-aired on Nippon TV and several local stations until 1979, when Shogakukan requested Toyama Television to cease broadcasting. Some of the segments were found in the archives of Imagica in 1995, and some others were recovered by Jun Masami in 2003. As of 2013, 21 of 52 segments are known to survive, two of which have no audio.",
"title": "Media"
},
{
"paragraph_id": 23,
"text": "Doraemon remained fairly exclusive in manga form until 1979 when a animation studio, Shin-Ei Animation (now owned by TV Asahi) produced an animated second attempt of Doraemon. The series aired on TV Asahi from April 2, 1979. Ryo Motohira served as chief director from 1981, and Tsutomu Shibayama from 1984. Eiichi Nakamura served as director of character designer, while Shunsuke Kikuchi was the composer. Nobuyo Ōyama voiced Doraemon in the series; because of this, in Asia, this version is sometimes referred to as the Ōyama Edition. In total, 1,787 episodes were produced and released in VHS and DVD by Toho. On April 15, 2005, a major renewal was carried out, including the replacement of voice actors and staff, and updated character designs (Doraemon (2005 TV series)). The third series is sometimes referred to in Asia as the Mizuta Edition, as a tribute for the voice actress for Doraemon, Wasabi Mizuta. It was released in DVD on February 10, 2006 under the title New TV-ban Doraemon (NEW TV 版 ドラえもん, Doraemon NEW TV Version) with Shogakukan Video banner.",
"title": "Media"
},
{
"paragraph_id": 24,
"text": "In May 2014, TV Asahi Corporation announced an agreement with The Walt Disney Company to bring the 2005 series to the Disney XD television channel and Disney Channel in the United States beginning in the summer of that year. Besides using the name changes that were used in AltJapan's English adaptation of the original manga, other changes and edits have also been made to make the show more relatable to an American audience, such as Japanese text being replaced with English text on certain objects like signs and graded papers, items such as yen notes being replaced by US dollar bills, and the setting being changed from Japan to the United States. Initial response to the edited dub was positive. The Disney adaptation began broadcast in Japan on Disney Channel from February 1, 2016. The broadcast offered the choice of the English voice track or a newly recorded Japanese track by the Japanese cast of the 2005 series.",
"title": "Media"
},
{
"paragraph_id": 25,
"text": "The anime has also been aired in over sixty countries worldwide. It premiered in Thailand in 1982, the Philippines in 1999, India in 2005, and Vietnam in 2010. Other Asian countries that broadcast the series include China, Hong Kong, Singapore, Taiwan, Malaysia, Indonesia, and South Korea. The series is licensed in EMEA regions by LUK International; it premiered in Spain in 1993 and France in 2003. It has also been distributed in South American countries, including Brazil, Colombia, and Chile. In 2017, POPS Worldwide, a Vietnamese multimedia company, collaborated with TV Asahi to release the anime series on YouTube and other digital platforms.",
"title": "Media"
},
{
"paragraph_id": 26,
"text": "By 2023, there have been 42 annual feature-length animated films produced by Shin-Ei Animation and released by Toho. The first twenty-five films are based on the 1979 anime, while the rest are based on the 2005 anime. Unlike the anime and manga series, the films are more action-adventure oriented, taking the familiar characters of Doraemon and placing them in a variety of exotic and perilous settings.",
"title": "Media"
},
{
"paragraph_id": 27,
"text": "A 3D computer animated film, Stand by Me Doraemon, debuted in Japan on August 8, 2014. Directed by Takashi Yamazaki and Ryūichi Yagi, it combines elements from the short stories of the manga series: \"All the Way from the Country of the Future\", \"Imprinting Egg\", \"Goodbye, Shizuka-chan\", \"Romance in Snowy Mountain\", \"Nobita's the Night Before a Wedding\", and \"Goodbye, Doraemon ...\" into a new complete story, from the first time Doraemon came to Nobita's house to Doraemon bidding farewell to Nobita. The film was a box office success, grossing $183.4 million worldwide. A sequel, Stand by Me Doraemon 2, also directed by Yamazaki and Yagi, was released on November 20, 2020.",
"title": "Media"
},
{
"paragraph_id": 28,
"text": "Several Doraemon short films were produced and released between 1989 and 2004. These include 2112: The Birth of Doraemon, a film about the life of Doraemon from birth before coming to Nobita; Doraemon: Nobita's the Night Before a Wedding, a film about the events related to the marriage of Nobita and Shizuka; The Day When I Was Born and Doraemon: A Grandmother's Recollections, the films about the relationship between Nobita and his parents along with his grandmother. Other short films focus on Dorami and The Doraemons. In 1981, Toho released What Am I for Momotaro, a film about Momotarō, the hero of Japanese folklore.",
"title": "Media"
},
{
"paragraph_id": 29,
"text": "In 1994, an educational OVA was made, titled Doraemon: Nobita to Mirai Note (ドラえもん のび太と未来ノート), where the main characters express the hope for a better Earth. The OVA was released in DVD along with the 13th issue of Fujiko F. Fujio Wonderland magazine in September 2004. A crossover episode of Doraemon with AIBOU: Tokyo Detective Duo aired on TV Asahi on November 9, 2018.",
"title": "Media"
},
{
"paragraph_id": 30,
"text": "The soundtrack of the 1973 anime series was composed by Nobuyoshi Koshibe, who also arranged the opening theme song \"Doraemon\" (ドラえもん) and the ending theme song \"Doraemon Rumba\" (ドラえもん ルンバ), both performed by Harumi Naitō. For the 1979 anime, Shunsuke Kikuchi was the composer, who arranged \"Doraemon no Uta\" (ドラえもんのうた); it had been performed by numerous singers, including Kumiko Ōsugi and Satoko Yamano. When the anime got a reboot in 2005, Kan Sawada was the composer of the series. There are four other opening themes, including an instrumental version of \"Doraemon no Uta\" performed by Twelve Girls Band; \"Hagushichao\" (ハグしちゃお) performed by Rimi Natsukawa; \"Yume wo Kanaete Doraemon\" (夢をかなえてドラえもん), the opening theme broadcast from 2007 to 2018; and \"Doraemon\" performed by Gen Hoshino, broadcast since October 2019.",
"title": "Media"
},
{
"paragraph_id": 31,
"text": "Numerous collections of theme songs of the anime series and feature films were initially available in cassettes. Since the 1990s, Doraemon songs have been released in CD, under the type of singles and compilation albums. Soundtracks of Doraemon feature films have been released by Nippon Columbia since 2001 in the album series \"Doraemon Soundtrack History\" (ドラえもんサウンドトラックヒストリー).",
"title": "Media"
},
{
"paragraph_id": 32,
"text": "Doraemon has been adapted into a musical, titled Doraemon the Musical: Nobita and the Animal Planet (舞台版ドラえもん のび太とアニマル惑星, Butaiban Doraemon: Nobita to Animaru Puranetto). Based on the 1990 anime film of the same name, it debuted at Tokyo Metropolitan Art Space on September 4, 2008, running through September 14. Shoji Kokami was the director and writer, Makoto Sakamoto played Nobita and Reiko Suho as Shizuka; Jaian and Suneo were portrayed by Tomohiro Waki and Kensaku Kobayashi, respectively; Wasabi Mizuta voiced Doraemon. The musical was later revived and ran at Sunshine Theater, Tokyo from March 26 to April 2, 2017, then later in other prefectures including Fukuoka, Osaka, Miyagi and Aichi. The 2017 revival is also directed and written by Kokami, with Mizuta reprising her role; Nobita, Shizuka, Jaian and Suneo were played by Yuuchi Ogoe, Hina Higuchi, Koki Azuma and Shō Jinnai, respectively.",
"title": "Media"
},
{
"paragraph_id": 33,
"text": "Many Japanese-only video games based on Doraemon have been developed. For instance, in 1983, Bandai developed Dokodemo Dorayaki Doraemon (どこでも ドラヤキ ドラえもん), an arcade game inspired by Pac-Man. Doraemon, a NES video game made by Hudson Soft, was released on December 12, 1986, and became one of the best-selling games of that year in Japan with over 1.15 million copies sold. On December 6, 2007, Sega published Doraemon Wii, the first Doraemon video game released on Wii. Doraemon can also be seen in Namco's Taiko no Tatsujin rhythm game series, such as in Taiko no Tatsujin: Sesson de Dodon ga Don! (2017). The first Doraemon game to receive a Western release was Doraemon Story of Seasons (2019). Card games with Doraemon themes have also been made in several special occasions, sometimes to exploit the popularity of feature films. In 2016, a special edition of Uno about the series' characters was released exclusively in Japan, as a result of a cooperation between Asatsu-DK and Mattel.",
"title": "Media"
},
{
"paragraph_id": 34,
"text": "In Japan, the Doraemon merchandising rights belong to Shogakukan-Shueisha Productions, which has produced and distributed a wide range of products under its brand, such as toys, food, stationery, action figures, gashapon, shoes, clothing, and others. Several companies have collaborated on the creation and distribution of products on the series and its characters, including Sanrio, Converse, Moleskine, and ESP Guitars, which has made guitars decorated with Doraemon characters; a further partnership of Doraemon with Uniqlo led to a line of clothing designed by Takashi Murakami. The Doraemon franchise has also collaborated with various Japanese brands, including Tsi Groove & Sports's Jack Bunny!! golf apparel brand, Unicharm's MamiPoko diaper brand, and the video games LINE Pop 2, Monster Strike, and Granblue Fantasy. Viz Media owns the Doraemon merchandising rights in North and Latin America, which has developed Doraemon-themed clothing and collectibles in collaboration with retail chain Hot Topic, and themed Happy Meals in a 2015 collaboration with McDonald's. Viz Media Europe (now Crunchyroll EMEA) manages the merchandising in Europe except Spain and Portugal; LUK International has obtained licenses in these two countries.",
"title": "Media"
},
{
"paragraph_id": 35,
"text": "Characters from Doraemon have been used in advertising through specific agreements with Shogakukan. For instance, following the Cool Japan initiative promoted by the Japanese government, Sharp Corporation produced a series of commercials featuring the characters of Doraemon and Nobita, which were broadcast in several ASEAN countries. In late 2011, Shogakukan and Toyota Motor Corporation joined forces to create a series of live-action commercials as part of Toyota's ReBorn ad campaign, which depicted the manga's characters two decades after being grown up, where Hollywood actor Jean Reno played Doraemon.",
"title": "Media"
},
{
"paragraph_id": 36,
"text": "Doraemon is considered one of the best-known manga of all time, a true Japanese cultural icon, and an essential part of family life of the Japanese post-war generation. Akihiro Motoyama observed that \"mothers who watched the movies when they were children are now taking their own children to see them\". It was also commercially successful: over 108 million books were sold in Japan by 1996. The 1979 and 2005 anime series also achieved high ratings on television. With the film Doraemon: Nobita's Secret Gadget Museum, the Doraemon anime film series reached 100 million tickets sold at the Japanese box office, surpassing Godzilla as the highest-grossing film franchise in Japan. By 2015, it had sold over 103 million tickets, and was the largest franchise by numbers of admissions in the country.",
"title": "Reception"
},
{
"paragraph_id": 37,
"text": "Doraemon was also a hit in Asia in general, and was considered one of the typical cases of Japanese soft power, although it was published without a license in some countries. The anime television series is available in over 60 countries, and reportedly getting high ratings in at least 30 countries. However, Doraemon was less successful in Western countries, because it was viewed as a children-only series, and there were some tight restrictions about publishing manga and broadcasting anime series there. The manga has sold over 170 million copies worldwide by 2012, and 250 million by 2019. Estimates show that Doraemon has generated at least more than $4.3 billion in merchandise sales by 2019, and over $1.7 billion from anime feature films by 2020, making it one of the highest-grossing media franchises of all time.",
"title": "Reception"
},
{
"paragraph_id": 38,
"text": "Outside Japan, Doraemon achieved particular success in Vietnam, with a record-breaking 40 million copies sold by 2006. The manga was first launched there in 1992 by Kim Đồng Publishing House, but the copyright from Shogakukan was not fully acquired until 1996. In 1993, the Vietnamese Ministry of Culture considered the manga's publication to be \"an impactful event for the improvement of children, youth and adult's likings ... [Doraemon] is a comprehensively educational book series which has the effect of developing children's personality\". Doraemon is now a cultural icon in Vietnam, having featured in many cultural events.",
"title": "Reception"
},
{
"paragraph_id": 39,
"text": "Doraemon received favorable reviews. Mark Schilling wrote, \"For kids whose lives are often so regulated, Doraemon represents a welcome breath of freedom and a glimpse of a funnier, friendlier world where all dreams, even foolish ones, can come true.\" Italian writer Massimo Nicora wrote that the manga \"can be interpreted as a type of book that criticizes, with irony, the omnipotence of science that pretends to solve every problem with its tools\", alluding to the fact that Doraemon's gadgets often end up making the problems even worse than they initially were, more than anything else. He added that it represents \"the metaphor of the childish imagination, which always manages to find the most bizarre and original solutions, in a continuous game of transformation of reality\".",
"title": "Reception"
},
{
"paragraph_id": 40,
"text": "Some critics considered that Nobita's flawed personality and modest background is different from the special or extraordinary characteristics usually seen in other typical anime and manga protagonists; this portrayal has been seen as reasons of its appeal as well as the contrary, especially in the United States. According to the Italian Parents Movement (Moige), in the manga, \"the lazy Nobita does not know any kind of appreciable evolution\", though there are still good points including \"the criticism of bullying, the goodness that transpires from the little Nobita and the positive figure of Shizuka\".",
"title": "Reception"
},
{
"paragraph_id": 41,
"text": "In his 2000 article, Leo Ching explained that the success of Doraemon in Asia was because it had reflected the Asian values such as imagination and responsibility, the same reason that Oshin, another Japanese cultural export, became well-known there. On the other hand, according to an analysis by Anne Allison, professor of cultural anthropology at Duke University, the strong point of it was not the variety of the gadgets, but the relationship between Doraemon and Nobita, which was particularly appreciated. Jason Thompson praised the \"silly situations\" and \"old fashioned, simple artwork\", with Doraemon's expression and comments adding to the \"surrounding elementary-school mischief\". On the manga's 50th anniversary, an op-ed published on Asahi Shimbun stated that the manga \"has already become a contemporary classic\".",
"title": "Reception"
},
{
"paragraph_id": 42,
"text": "Doraemon has received numerous accolades. It won the Japan Cartoonists Association Award twice in 1973 and 1994, the former for Excellence Award while the latter for Minister of Education, Science and Technology Award. In 1982, it received the first Shogakukan Manga Award for children's manga. In 1997, the manga won the Grand Prize at the first Tezuka Osamu Cultural Prize. The 1979 series won the award from the Japanese Agency for Cultural Affairs four times for best television series in 1984, 1985, 1988 and 1989.",
"title": "Reception"
},
{
"paragraph_id": 43,
"text": "A 2006 poll among 80,000 Japanese fans for the 10th anniversary of the Japan Media Arts Festival placed Doraemon at fifth among the top ten best manga of all time. The 2005 and 2006 surveys conducted by TV Asahi found the Doraemon anime ranked fifth and third, respectively, among the 100 most favorite anime series of all time. In 2010, a survey conducted by researchers of Tokyo Polytechnic University found that most responders considered Doraemon, along with Dragon Ball franchise, to be the anime series that represents Cool Japan. In a 2013 survey, Doraemon was found to be the best anime recommended for foreign people.",
"title": "Reception"
},
{
"paragraph_id": 44,
"text": "Doraemon has been blamed for having a negative impact on children, due to the controversial traits of the characters in the anime. The character has received criticism in China, where some media outlets considered Doraemon to be a politically subversive character and that it was a tool of Japan's \"cultural invasion\". In 2016, a resolution to ban Hindi dubbed Doraemon anime series was submitted in Pakistan. Around the same time, legal notices were served against several companies in India, targeting Doraemon and Crayon Shin-chan for bans (which did not materialize), as having an adverse effect on children. Disney Channel India, the regional broadcaster of the anime, was banned in Bangladesh and Pakistan citing non-availability of localized dubs for content including Doraemon.",
"title": "Reception"
},
{
"paragraph_id": 45,
"text": "The Doraemon manga has inspired many other mangakas; these include Eiichiro Oda, the creator of One Piece with the idea of \"Devil Fruits\", and Masashi Kishimoto, the creator of Naruto, who showed interest in drawing characters from anime shows during his childhood, including Doraemon. The manga has also been mentioned in Gin Tama and Great Teacher Onizuka. The character Doraemon is considered one of the cultural icons in Japan, and one of the most well-known characters in manga history; some critics compared his notability with Mickey Mouse and Snoopy. Mark Schilling noted that Doraemon's \"Take-Copter\" is familiar among Japanese people \"just as Snoopy's biplane is familiar to most Americans\".",
"title": "Cultural impact and legacy"
},
{
"paragraph_id": 46,
"text": "On April 22, 2002, on the special issue of Asian Hero in Time magazine, Doraemon was the only anime character to be named one of the twenty-two Asian Heroes, and was described as \"The Cuddliest Hero in Asia\". A 2007 poll by Oricon shown that Doraemon was the second-strongest manga character ever, behind only Son Goku of Dragon Ball. Doraemon is also referred as something with the ability to satisfy all wishes.",
"title": "Cultural impact and legacy"
},
{
"paragraph_id": 47,
"text": "In 2005, the Taiwan Society of New York selected Doraemon as a culturally significant work of Japanese otaku pop-culture in its exhibit Little Boy: The Arts of Japan's Exploding Subculture, curated by renowned artist Takashi Murakami. In 2008, the Japanese Ministry of Foreign Affairs appointed Doraemon as the first anime cultural ambassador; a Ministry spokesperson explained the decision as an attempt to help people in other countries understand Japanese anime better and to deepen their interest in Japanese culture. On September 3, 2012, Doraemon was granted official residence in the city of Kawasaki, Kanagawa, one hundred years before he was born. In the same year, Hong Kong celebrated the birthday of Doraemon 100 years early with a series of displays of the character. In April 2013, Doraemon was chosen as Japan's ambassador in Tokyo's bid to host the 2020 Summer Olympics and 2020 Summer Paralympics. He appeared in the 2016 Summer Olympics closing ceremony to promote the 2020 Summer Olympics in Tokyo.",
"title": "Cultural impact and legacy"
},
{
"paragraph_id": 48,
"text": "A Fujiko F. Fujio museum opened in Kawasaki on September 3, 2011, featuring Doraemon as the star of the museum. The National Museum of Singapore held a time-travelling exhibition in October 2020 as a tribute to the manga. After the 2011 Tōhoku earthquake and tsunami, Shogakukan released an earthquake survival guidebook, which included the main cast of the Doraemon manga series. TV Asahi launched the Doraemon Fund charity fund to raise money for natural disasters in 2004, and in 2011. In 2020, Mumbai's Sion Friends Circle group distributed food and books to kids using mascots, one being Doraemon, to help during the COVID-19 pandemic. In Vietnam, a Doraemon scholarship fund was established in 1996, and the Doraemon character has been used for education of traffic safety. Doraemon's creator, Fujiko F. Fujio, received the Culture Fighter Medal from the Vietnamese Ministry of Culture in 1996 for his contributions to young education through the manga.",
"title": "Cultural impact and legacy"
},
{
"paragraph_id": 49,
"text": "Many prominent figures have been nicknamed after the cast of Doraemon: politician Osamu Fujimura is known as the \"Doraemon of Nagatacho\" due to his figure and warm personality, and sumo wrestler Takamisugi was nicknamed \"Doraemon\" because of his resemblance to the character. In 2015, a group of people in a drought-affected village in northern Thailand used a Doraemon toy to complete a rain-ritual, in order to avoid controversies that would occur by using real animals.",
"title": "Cultural impact and legacy"
},
{
"paragraph_id": 50,
"text": "A parody of Doraemon created by Hikari Fujisaki, titled Nozoemon (のぞえもん), was first serialized in Nihon Bungeisha's Comic Heaven magazine in September 2014, with the compiled book volume released on June 9, 2015; however, it was discontinued in August 2015 due to content issues.",
"title": "Cultural impact and legacy"
}
] | Doraemon (ドラえもん) is a Japanese manga series written and illustrated by Fujiko F. Fujio. The manga was first serialized in December 1969. Its chapters were collected in 45 tankōbon volumes published by Shogakukan from 1974 to 1996. The story revolves around an earless robotic cat named Doraemon, who travels back in time from the 22nd century to aid a boy named Nobita Nobi. The manga spawned a media franchise. Three anime TV series have been adapted in 1973, 1979, and 2005. Additionally, Shin-Ei Animation has produced over forty animated films, including two 3D computer-animated films, all of which are distributed by Toho. Various types of merchandise and media have been developed, including soundtrack albums, video games, and musicals. The manga series was licensed for an English language release in North America, via Amazon Kindle, by a collaboration of Fujiko F. Fujio Pro with Voyager Japan and AltJapan Co., Ltd. The anime series was licensed by Disney for an English-language release in North America in 2014, and LUK International in Europe, the Middle East and Africa. Doraemon was well-received by critics and became a hit in many Asian countries. It won numerous awards, including the Japan Cartoonists Association Award in 1973 and 1994, the Shogakukan Manga Award for children's manga in 1982, and the Tezuka Osamu Cultural Prize in 1997. By 2019, it has sold over 250 million copies worldwide, becoming one of the best-selling manga series in history. The Doraemon character has been viewed as a Japanese cultural icon, and was appointed as the first "anime ambassador" in 2008 by the country's Foreign Ministry. | 2001-09-10T18:24:09Z | 2023-12-28T21:54:48Z | [
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] | https://en.wikipedia.org/wiki/Doraemon |
8,414 | Dartmoor Preservation Association | Dartmoor Preservation Association (DPA) is one of the oldest environmental or amenity bodies in the UK. It was founded in 1883. It concerns itself with Dartmoor, a National Park in Devon, south-west England. It began with two main areas of concern. Firstly, commoners' rights were being eroded through army use, including the firing of live artillery shells, and piecemeal enclosure of land around the margins. Secondly, there was increasing public interest in Dartmoor's scenery, archaeology, history and wildlife
The DPA has opposed what it considered to be unsuitable developments on Dartmoor throughout its history. In its founding year, the secretary, Robert Burnard persuaded the War Department not to fire on the Okehampton Firing Range on Saturdays to allow access to the public. Many battles have been fought since, particularly against the military presence and the proposed building of reservoirs on the moor, notably under the Chairmanship of Lady Sayer, granddaughter of Robert Burnard.
The DPA continues to follow the same objectives as when it was founded. For example, in June 2015, it supported the inhabitants of Widecombe-in-the-Moor against the erecting of a telecommunications mast in an area of pristine countryside against the wishes of the local population.
Dartmoor Preservation Association is a registered charity, Number 215665.
Dartmoor is said to be one of the last remaining areas of wilderness in Britain, but it has been a managed landscape since the late Neolithic (3,000-2,500 BCE). The Bronze Age inhabitants (from 2,500 to 750 BCE) cleared ancient forest and developed farming. They made extensive use of surface moorstone in the construction of roundhouses (their remains now seen as "hut circles"), enclosures, land-dividing reaves, stone rows, stone circles, menhirs and kistvaens.
Farming has continued through the Medieval period to the present day, but a more disruptive activity to the landscape was the appearance of tin-mining, firstly by stream-working, then by lode-working and finally by underground mining. Many valleys have been dug over and scarred, leaving a rich industrial archaeology. Other activities such as newtake wall building, peat cutting, rabbit warrening, quarrying, clay extraction and the building of a prominent prison have all left marks on the moor. Recent undertakings have left more obvious changes: the building of reservoirs and the planting of conifer forests.
The use of moorstone continued up to recent times with the extensive building of dry stone walls around farm newtakes. Later, stone was cut and dressed. The use of moorstone continued to such an extent that in 1847 boundary markers were cut around Pew Tor to protect it. Marker stones were erected around Roos Tor. The taking of stone started to change the Dartmoor landscape: for example Eric Hemery (writing in 1983) stated that Swell Tor had been "decapitated and disembowelled by the quarrymen".
In August 1881, a public meeting was convened by the Portreeve of Tavistock in the Guildhall to discuss the continued taking of stone, particularly from landmark tors. The DPA was founded in 1883. The protected area around Pew Tor was extended in December 1896. In 1901, the DPA commissioned a report into damage to ancient monuments, caused by the taking of stone for building and road-mending, and into unlawful enclosures of common land.
The first publication of the DPA, in 1890, was a short history of commoners' rights on Dartmoor and the commons of Devon. This notes a decrease in the numbers of animals even in medieval times: in 1296 – 5,000 cattle, 487 horses, 131 folds of sheep; in 1316 – 3,292 cattle, 368 horses, 100 folds of sheep. An important battle occurred in 1894 when the Corporation of London attempted to buy the whole of Dartmoor in order to pipe its water to Paddington alongside Brunel’s recently converted railway, when it went from broad gauge to standard gauge. The DPA led the revolt against this. In 1897, the DPA went to court to fight successfully the enclosure of a section of Peter Tavy Great Common, in support of a farmer. Commoners rights seem to have been a settled issue in recent years: except for where they are impinged upon by the military presence.
Dartmoor Training Area has been used regularly for military training since 1873, although it was used earlier during the Napoleonic and Crimean Wars. In 1906–07, seven miles of roads were built on the north moor to facilitate the movement of guns. There are three established firing ranges at Okehampton, Willsworthy and Merrivale. The area taken up with live firing ranges is 9,187 hectares (22,700 acres) and they are used on average 120 days each year. They are used for small arms, mortars and artillery smoke and illuminating shells.
The use of the moor by the military has been a major concern of the DPA since its founding. In its first year, Robert Burnard (DPA Secretary) persuaded the War Department not to fire on the Okehampton Firing Range on Saturdays so that there may be some public access to the area. Lady Sylvia Sayer was very outspoken about it being totally at odds with the area being designated as a National Park. In 1963 the DPA published a widely circulated 24-page booklet entitled Misuse of a National Park which includes photographs of unexploded shells lying on the open moor, corrugated iron buildings, large craters, a derelict tank used as a target, bullet marks on standing stones, etc. It also contains details of a 1958 incident in which a young boy was killed by a mortar shell near Cranmere Pool.
Since the 1960s there has been much less military damage and litter as a result of the DPA persuading the Services to be more cautious. The military have changed since the Victorian era, they now have 120 conservation groups across the Ministry of Defence (MOD), including Dartmoor Military Conservation Group. The current leases run for many years, with Cramber Tor most recently being granted a further 40-year licence.
Early afforestation occurred when Brimpts was planted with trees in 1862. The Forestry Commission was founded in 1919, following World War I and in that year the Duchy of Cornwall planted 800 acres of conifers at Fernworthy. In 1921, Plymouth Corporation planted conifers around Burrator Reservoir. The Forestry Commission planted Bellever and Laughter Tor farms in 1930-32 and in 1944-1945 Soussons Down was also planted. The DPA opposed these post-war plantings and R. Hansford Worth (1868-1950, a Plymouth engineer, scientist and antiquarian) delivered a lecture fiercely critical of the Duchy of Cornwall as the landowners at The Plymouth Athenaeum, using the argument of encroachment on the rights of common and loss of ancient monuments. DPA opposition to forestry on Dartmoor arose again in 1953 when it wrote a policy on woodlands in the then-new national park. Opposition was exercised when Hawn, Dendles and High House Wastes, all near Cornwood, were designated for tree planting in 1959. Argument continued while Hawns and Dendles Wastes were ploughed in 1960. High House Waste was purchased by the DPA in 1964 and the Nature Conservancy (UK) bought neighbouring Dendles in 1965. The situation in 2015 is that some of the Dartmoor plantations have been affected by the fungal disease Phytophthora ramorum which results in widespread clear felling to prevent further spread of the disease. The policy now is to replant with more native hardwood trees although more resistant conifers are also being used.
There are eight Dartmoor reservoirs, with the earliest being Tottiford Reservoir, 1861. Three were built in the mid-20th century: Fernworthy, 1942; Avon, 1957 and Meldon, 1972, and the DPA fought many battles over these. It opposed plans for reservoirs on Brent Moor (1899) and Holne Moor (1901) where, later, the Avon Reservoir and Venford Reservoirs were respectively built. The DPA's opposition was supported in the House of Commons with argument made regarding the effects on the local water table. The DPA was one of many local and national amenity bodies that fought the building of the Meldon dam. The preservation battle for the Meldon valley was recorded in a DPA publication. The DPA offered a viable alternative site, Gorhuish Valley, for various reasons, including the fact that minerals such as arsenic would leach into the water supply if Meldon were selected. The Meldon story was discussed many times in Parliament. Another battle was fought against the flooding of the Swincombe valley to form another reservoir. This was rejected in parliament in 1970, revived in 1974 and finally resolved by the building of the Roadford Reservoir to the west of the moor. In 1985 the DPA used funds from a bequest to purchase 50 acres of land where the dam of a reservoir at Swincombe would have to be.
The National Parks and Access to the Countryside Act 1949 led to Dartmoor being one of the first four parks to be designated, by an order made on 15 August 1951 and confirmed on 30 October 1951. Shortly after this, the DPA tried to ensure that the new National Park was run by an independent committee and not by the Dartmoor Standing Committee that was a subcommittee of Devon County Council Planning Committee. The committee was reformed as Dartmoor National Park Committee under the Local Government Act 1972 but it was still a subcommittee of Devon County Council and as such it was not seen to be an independent guardian of the moor by the DPA. It was not until 1997 that an independent Dartmoor National Park Authority was enabled under the Environment Act 1995 as a free-standing local authority, forty-four years after the park was created, although it is still dominated by local authorities and government appointees.
The DPA learned in October 1951 that the BBC planned to build a 750-foot television mast on North Hessary Tor, near Princetown, that was erected in 1955. This was to be a relay from a transmitting station at Wenvoe, South Wales. The DPA objected to this threat and sought expert opinion, offered alternative solutions, pressed for a public enquiry, engaged a lawyer, held public meetings, distributed pamphlets, wrote to the press and petitioned parliament. Eventually, a public enquiry was announced. When the decision was made to permit the mast, there were a number of conditions, included among them was that the development was built near the tor, leaving it still intact, and that its new approach road should not be fenced. During the process of obtaining land for the transmitter, one MP asked in the House of Commons: "Will the Assistant Postmaster-General bear in mind that we have no desire to hinder the provision of this station but that it is felt that ancient common rights such as these, that have existed for a thousand years, should be adequately protected or properly extinguished by due process of law?"
During World War II, the Royal Air Force (RAF) built a mast and buildings on Peek Hill, as RAF Sharpitor. In 1956, permission was granted to rebuild the station as part of the "Gee" radio navigation system, to be occupied for ten years. There followed delay in leaving and a proposal was made in 1970 by Devon & Cornwall Police to use the mast, which was rejected. Then later that year Plymouth Corporation wanted to use the exposed site for housing juvenile offenders. This was also rejected, but Plymouth appealed. At a public enquiry in June 1973 Lady Sylvia Sayer represented the DPA and permission for development on the site was refused. A few years later, DPA fought successfully in support of South West Water (SWW) against renewed calls for a new reservoir at Swincombe. To mark the victory, Sylvia Sayer asked SWW if DPA could purchase the rocky outcrop of Sharpitor. The DPA purchased 32 acres in February 1984.
Okehampton lies on the A30 main road, the shortest route from London to west Devon and Cornwall. The need for a bypass was mooted in 1963. In 1975, three routes were considered: a northern route through mainly farmland, a central route using a railway, and a southern route through Dartmoor National Park. In August 1976, the Department of the Environment announced the preferred route was through the National Park. A major event on the timeline of this project was a 96-day public enquiry from 1 May 1979 to 4 February 1980 held in Okehampton. In March 1984, the DPA with other organisations petitioned Parliament opposing compulsory purchase orders on public open spaces. The Secretary of State announced in July 1985 that he was introducing a bill to reverse the decision of a Joint Parliamentary Committee and confirm a route through the National Park. This was followed by a confirmation bill in November 1985 that was passed in the House of Lords on 5 December 1985. Construction started in November 1986 and the road was opened on 19 July 1988.
The DPA continues to follow the same objectives as when it was founded. The activities have widened, involving local partners, it has a calendar of events, walks and work days with its Conservation Team undertaking a variety of moorland projects, it funds the supply of walking boots to some children who need them for the Duke of Edinburgh Award Scheme through the Moor Boots Scheme, it collaborates with the Campaign for National Parks, it monitors the activities of Dartmoor National Park Authority who run the National Park. It objected to eight planning proposals (with success in seven cases), with many other achievements in the DPA Director's Annual Report. The DPA remains true to its original objectives and has also added other activities in support of Dartmoor and its inhabitants.
The china clay industry on Dartmoor was established long before the DPA was founded. The earliest record of a china clay pit refers to Hook Lake in 1502. The area was surveyed around 1827 by Cornishmen with thirty years experience in the clay industry. They obtained a 21-year lease in 1830, from the Earl of Morley who owned the land, to work the area between Lee Moor and Shaugh Moor. A rival pit was opened at Leftlake in about 1850 and at Hemerdon and Broomage in about 1855. Further pits were opened at Cholwichtown, Whitehill Yeo and Wigford Down/Brisworthy (circa 1860). Others followed at Smallhanger and Headon in the 1870s. Redlake started working in 1910. China clay pits are open cast mines that result in large holes in the ground accompanied by large waste tips. Over time, the pits become larger and more ground is needed for the waste, changing the landscape: the effect of this can be seen from space.
The DPA argues that this is an activity that does not agree with the ethos of a National Park, whose purpose is to protect landscape from unsuitable development. In 1994, the National Park boundaries were changed to include common land at Shaugh Moor and exclude china clay worked land at Lee Moor. The DPA revived its campaign with the publication of a booklet in 1999 when the Blackabrook Valley, Crownhill Down and Shaugh Moor, near the popular tourist area of Cadover Bridge, all came under threat from exploitation or dumping of waste. The china clay companies relinquished planning permissions in 2001. However, in November 2009, the clay companies, Sibelco and Imerys, produced a report reviewing old mineral permissions under the Environment Act 1995 with a view to joining up two pits. A presumed Bronze Age barrow, known as Emmets Post, was to be removed and three other monuments may be affected. The DPA were recorded twice, with other bodies, in a Devon County Council Development Management Committee Report for their representations in securing the future of the three areas where planning permissions were relinquished in 2001. Oxford Archaeology held an open day during their excavation of Emmets Post in 2014 prior to its removal.
The DPA and Exmoor Society held a joint reception at the House of Lords on 6 November 2008, hosted by Baroness Mallalieu, to lobby members of both Houses of Parliament and relevant Ministers about ensuring that environmental schemes for the uplands are "fit for purpose". Both organisations funded an invited number of upland hill farmers to attend.
The excavation in August 2011 on the north moor of a Bronze Age burial kistvaen, or cist, that was originally uncovered in 2001 was part-funded by the DPA, along with other bodies.
A conference for the upland farmers of Bodmin Moor, Exmoor and Dartmoor was held as a joint venture between the South West Uplands Federation and the DPA. It was run by the DPA at Exeter Racecourse in October 2012, with 150 delegates. Speakers came from the Foundation for Common Land, the Forest of Dartmoor Commoners, the University of Gloucestershire, the National Farmers Union of England and Wales and the Open Spaces Society. The CEO raised sponsorship from Dartmoor National Park, Exmoor National Park, Natural England, Duchy of Cornwall and the Exmoor Society - this reflecting the standing of the DPA with those bodies.
Two major projects to underground overhead power cables in Dartmoor National Park have been completed in a joint project between Western Power Distribution, the South West Protected Landscapes Forum (SWPLF) and Dartmoor National Park Authority. The two schemes on Holne Moor and Walkhampton Common between them remove nearly 6 km of overhead line from open moorland. At nearly 5 km, the Walkhampton scheme is the largest to be undertaken in the South West region by Western Power Distribution. The old overhead line was readily visible from the B3212 Princetown to Yelverton Road, strung across Walkhampton Common from Devil's Elbow to just above Horseyeatt at Peek Hill. The works to provide the new underground supply were mainly undertaken on the highway to minimise the impact on the sensitive moorland landscape, its archaeology, wildlife and livestock. The DPA has supported the undergrounding of these visually intrusive power lines for many years.
The Dartmoor Conservation Garden is a joint project between DPA and Dartmoor National Park Authority (DNPA) and is located in the Jack Wigmore Garden behind the High Moorland Centre in Princetown: this is a memorial garden to a former Chair of the Authority. It is planted with a cross-section of typical native Dartmoor plants. It also houses some typical Dartmoor archaeological features, such as a 4,000-year-old Bronze Age burial kistvaen (or cist) and a Medieval granite cross from Ter Hill. This marked the Monk's Path but was constantly being pushed over by cattle. The purpose of the Garden is to illustrate the biodiversity on Dartmoor. The project came online in June 2015.
The DPA were involved in a campaign in June 2015 against four telecommunications masts planned for Dartmoor, with the first to be erected in the village of Widecombe. At short notice, the DPA banners were taken out, letters written, press interviews given and support given to the villagers when an inflatable mast was demonstrated – with the effect that the planning application was withdrawn.
In common with other amenity bodies, such as those for the Lake District, Peak District, Pembrokeshire Coast, Yorkshire Dales Three Peaks and the New Forest Trust, the image of Dartmoor Preservation Association is evolving from its Victorian origins, although the original name is being retained. Friends of Dartmoor projects a more modern image of preservation where several years of diplomacy have achieved good relations with the partner agencies that operate in the Dartmoor arena. This is due mainly to the efforts of the previous CEO, James Paxman and his successor, Phil Hutt.
The DPA Constitution, objectives and policies are published on the DPA web site.
The objectives enshrined in the constitution are the protection, preservation and enhancement in the public interest of the landscape, antiquities, flora and fauna, natural beauty, cultural heritage and scientific interest of Dartmoor. Also the protection and preservation of public access to and on Dartmoor subject to the ancient rights of commoners. Co-operation with the commoners and any organisation in achieving DPA objectives, also the study of and the recording and publication of information upon the antiquities, history and natural history of Dartmoor.
The DPA has twenty-two policies listed on its web site: regarding access and rights of way, fencing, protecting monuments, diverse habitats, bracken, china clay quarrying, military training and live firing, hill farming and small scale traditional local industries, quarrying, television and telephone masts, wind farms, planning applications, housing developments, woodlands and forestry, ponies, swaling, and recreational activities.
The DPA conservation team meet throughout the year to work on a number of ongoing projects; from gorse clearance, to habitat protection and archaeological surveying. A quarterly timetable is released both on the organisation's website and through its member publications, along with details of how to get involved. The team also host an annual open day at the DPA land holding of Pudsham Meadows. | [
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"title": "'Fighting to keep Dartmoor wild and free since 1883.'"
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"paragraph_id": 1,
"text": "Dartmoor Preservation Association (DPA) is one of the oldest environmental or amenity bodies in the UK. It was founded in 1883. It concerns itself with Dartmoor, a National Park in Devon, south-west England. It began with two main areas of concern. Firstly, commoners' rights were being eroded through army use, including the firing of live artillery shells, and piecemeal enclosure of land around the margins. Secondly, there was increasing public interest in Dartmoor's scenery, archaeology, history and wildlife",
"title": "'Fighting to keep Dartmoor wild and free since 1883.'"
},
{
"paragraph_id": 2,
"text": "The DPA has opposed what it considered to be unsuitable developments on Dartmoor throughout its history. In its founding year, the secretary, Robert Burnard persuaded the War Department not to fire on the Okehampton Firing Range on Saturdays to allow access to the public. Many battles have been fought since, particularly against the military presence and the proposed building of reservoirs on the moor, notably under the Chairmanship of Lady Sayer, granddaughter of Robert Burnard.",
"title": "'Fighting to keep Dartmoor wild and free since 1883.'"
},
{
"paragraph_id": 3,
"text": "The DPA continues to follow the same objectives as when it was founded. For example, in June 2015, it supported the inhabitants of Widecombe-in-the-Moor against the erecting of a telecommunications mast in an area of pristine countryside against the wishes of the local population.",
"title": "'Fighting to keep Dartmoor wild and free since 1883.'"
},
{
"paragraph_id": 4,
"text": "Dartmoor Preservation Association is a registered charity, Number 215665.",
"title": "'Fighting to keep Dartmoor wild and free since 1883.'"
},
{
"paragraph_id": 5,
"text": "Dartmoor is said to be one of the last remaining areas of wilderness in Britain, but it has been a managed landscape since the late Neolithic (3,000-2,500 BCE). The Bronze Age inhabitants (from 2,500 to 750 BCE) cleared ancient forest and developed farming. They made extensive use of surface moorstone in the construction of roundhouses (their remains now seen as \"hut circles\"), enclosures, land-dividing reaves, stone rows, stone circles, menhirs and kistvaens.",
"title": "Background"
},
{
"paragraph_id": 6,
"text": "Farming has continued through the Medieval period to the present day, but a more disruptive activity to the landscape was the appearance of tin-mining, firstly by stream-working, then by lode-working and finally by underground mining. Many valleys have been dug over and scarred, leaving a rich industrial archaeology. Other activities such as newtake wall building, peat cutting, rabbit warrening, quarrying, clay extraction and the building of a prominent prison have all left marks on the moor. Recent undertakings have left more obvious changes: the building of reservoirs and the planting of conifer forests.",
"title": "Background"
},
{
"paragraph_id": 7,
"text": "The use of moorstone continued up to recent times with the extensive building of dry stone walls around farm newtakes. Later, stone was cut and dressed. The use of moorstone continued to such an extent that in 1847 boundary markers were cut around Pew Tor to protect it. Marker stones were erected around Roos Tor. The taking of stone started to change the Dartmoor landscape: for example Eric Hemery (writing in 1983) stated that Swell Tor had been \"decapitated and disembowelled by the quarrymen\".",
"title": "History of the association"
},
{
"paragraph_id": 8,
"text": "In August 1881, a public meeting was convened by the Portreeve of Tavistock in the Guildhall to discuss the continued taking of stone, particularly from landmark tors. The DPA was founded in 1883. The protected area around Pew Tor was extended in December 1896. In 1901, the DPA commissioned a report into damage to ancient monuments, caused by the taking of stone for building and road-mending, and into unlawful enclosures of common land.",
"title": "History of the association"
},
{
"paragraph_id": 9,
"text": "The first publication of the DPA, in 1890, was a short history of commoners' rights on Dartmoor and the commons of Devon. This notes a decrease in the numbers of animals even in medieval times: in 1296 – 5,000 cattle, 487 horses, 131 folds of sheep; in 1316 – 3,292 cattle, 368 horses, 100 folds of sheep. An important battle occurred in 1894 when the Corporation of London attempted to buy the whole of Dartmoor in order to pipe its water to Paddington alongside Brunel’s recently converted railway, when it went from broad gauge to standard gauge. The DPA led the revolt against this. In 1897, the DPA went to court to fight successfully the enclosure of a section of Peter Tavy Great Common, in support of a farmer. Commoners rights seem to have been a settled issue in recent years: except for where they are impinged upon by the military presence.",
"title": "History of the association"
},
{
"paragraph_id": 10,
"text": "Dartmoor Training Area has been used regularly for military training since 1873, although it was used earlier during the Napoleonic and Crimean Wars. In 1906–07, seven miles of roads were built on the north moor to facilitate the movement of guns. There are three established firing ranges at Okehampton, Willsworthy and Merrivale. The area taken up with live firing ranges is 9,187 hectares (22,700 acres) and they are used on average 120 days each year. They are used for small arms, mortars and artillery smoke and illuminating shells.",
"title": "History of the association"
},
{
"paragraph_id": 11,
"text": "The use of the moor by the military has been a major concern of the DPA since its founding. In its first year, Robert Burnard (DPA Secretary) persuaded the War Department not to fire on the Okehampton Firing Range on Saturdays so that there may be some public access to the area. Lady Sylvia Sayer was very outspoken about it being totally at odds with the area being designated as a National Park. In 1963 the DPA published a widely circulated 24-page booklet entitled Misuse of a National Park which includes photographs of unexploded shells lying on the open moor, corrugated iron buildings, large craters, a derelict tank used as a target, bullet marks on standing stones, etc. It also contains details of a 1958 incident in which a young boy was killed by a mortar shell near Cranmere Pool.",
"title": "History of the association"
},
{
"paragraph_id": 12,
"text": "Since the 1960s there has been much less military damage and litter as a result of the DPA persuading the Services to be more cautious. The military have changed since the Victorian era, they now have 120 conservation groups across the Ministry of Defence (MOD), including Dartmoor Military Conservation Group. The current leases run for many years, with Cramber Tor most recently being granted a further 40-year licence.",
"title": "History of the association"
},
{
"paragraph_id": 13,
"text": "Early afforestation occurred when Brimpts was planted with trees in 1862. The Forestry Commission was founded in 1919, following World War I and in that year the Duchy of Cornwall planted 800 acres of conifers at Fernworthy. In 1921, Plymouth Corporation planted conifers around Burrator Reservoir. The Forestry Commission planted Bellever and Laughter Tor farms in 1930-32 and in 1944-1945 Soussons Down was also planted. The DPA opposed these post-war plantings and R. Hansford Worth (1868-1950, a Plymouth engineer, scientist and antiquarian) delivered a lecture fiercely critical of the Duchy of Cornwall as the landowners at The Plymouth Athenaeum, using the argument of encroachment on the rights of common and loss of ancient monuments. DPA opposition to forestry on Dartmoor arose again in 1953 when it wrote a policy on woodlands in the then-new national park. Opposition was exercised when Hawn, Dendles and High House Wastes, all near Cornwood, were designated for tree planting in 1959. Argument continued while Hawns and Dendles Wastes were ploughed in 1960. High House Waste was purchased by the DPA in 1964 and the Nature Conservancy (UK) bought neighbouring Dendles in 1965. The situation in 2015 is that some of the Dartmoor plantations have been affected by the fungal disease Phytophthora ramorum which results in widespread clear felling to prevent further spread of the disease. The policy now is to replant with more native hardwood trees although more resistant conifers are also being used.",
"title": "History of the association"
},
{
"paragraph_id": 14,
"text": "There are eight Dartmoor reservoirs, with the earliest being Tottiford Reservoir, 1861. Three were built in the mid-20th century: Fernworthy, 1942; Avon, 1957 and Meldon, 1972, and the DPA fought many battles over these. It opposed plans for reservoirs on Brent Moor (1899) and Holne Moor (1901) where, later, the Avon Reservoir and Venford Reservoirs were respectively built. The DPA's opposition was supported in the House of Commons with argument made regarding the effects on the local water table. The DPA was one of many local and national amenity bodies that fought the building of the Meldon dam. The preservation battle for the Meldon valley was recorded in a DPA publication. The DPA offered a viable alternative site, Gorhuish Valley, for various reasons, including the fact that minerals such as arsenic would leach into the water supply if Meldon were selected. The Meldon story was discussed many times in Parliament. Another battle was fought against the flooding of the Swincombe valley to form another reservoir. This was rejected in parliament in 1970, revived in 1974 and finally resolved by the building of the Roadford Reservoir to the west of the moor. In 1985 the DPA used funds from a bequest to purchase 50 acres of land where the dam of a reservoir at Swincombe would have to be.",
"title": "History of the association"
},
{
"paragraph_id": 15,
"text": "The National Parks and Access to the Countryside Act 1949 led to Dartmoor being one of the first four parks to be designated, by an order made on 15 August 1951 and confirmed on 30 October 1951. Shortly after this, the DPA tried to ensure that the new National Park was run by an independent committee and not by the Dartmoor Standing Committee that was a subcommittee of Devon County Council Planning Committee. The committee was reformed as Dartmoor National Park Committee under the Local Government Act 1972 but it was still a subcommittee of Devon County Council and as such it was not seen to be an independent guardian of the moor by the DPA. It was not until 1997 that an independent Dartmoor National Park Authority was enabled under the Environment Act 1995 as a free-standing local authority, forty-four years after the park was created, although it is still dominated by local authorities and government appointees.",
"title": "History of the association"
},
{
"paragraph_id": 16,
"text": "The DPA learned in October 1951 that the BBC planned to build a 750-foot television mast on North Hessary Tor, near Princetown, that was erected in 1955. This was to be a relay from a transmitting station at Wenvoe, South Wales. The DPA objected to this threat and sought expert opinion, offered alternative solutions, pressed for a public enquiry, engaged a lawyer, held public meetings, distributed pamphlets, wrote to the press and petitioned parliament. Eventually, a public enquiry was announced. When the decision was made to permit the mast, there were a number of conditions, included among them was that the development was built near the tor, leaving it still intact, and that its new approach road should not be fenced. During the process of obtaining land for the transmitter, one MP asked in the House of Commons: \"Will the Assistant Postmaster-General bear in mind that we have no desire to hinder the provision of this station but that it is felt that ancient common rights such as these, that have existed for a thousand years, should be adequately protected or properly extinguished by due process of law?\"",
"title": "History of the association"
},
{
"paragraph_id": 17,
"text": "During World War II, the Royal Air Force (RAF) built a mast and buildings on Peek Hill, as RAF Sharpitor. In 1956, permission was granted to rebuild the station as part of the \"Gee\" radio navigation system, to be occupied for ten years. There followed delay in leaving and a proposal was made in 1970 by Devon & Cornwall Police to use the mast, which was rejected. Then later that year Plymouth Corporation wanted to use the exposed site for housing juvenile offenders. This was also rejected, but Plymouth appealed. At a public enquiry in June 1973 Lady Sylvia Sayer represented the DPA and permission for development on the site was refused. A few years later, DPA fought successfully in support of South West Water (SWW) against renewed calls for a new reservoir at Swincombe. To mark the victory, Sylvia Sayer asked SWW if DPA could purchase the rocky outcrop of Sharpitor. The DPA purchased 32 acres in February 1984.",
"title": "History of the association"
},
{
"paragraph_id": 18,
"text": "Okehampton lies on the A30 main road, the shortest route from London to west Devon and Cornwall. The need for a bypass was mooted in 1963. In 1975, three routes were considered: a northern route through mainly farmland, a central route using a railway, and a southern route through Dartmoor National Park. In August 1976, the Department of the Environment announced the preferred route was through the National Park. A major event on the timeline of this project was a 96-day public enquiry from 1 May 1979 to 4 February 1980 held in Okehampton. In March 1984, the DPA with other organisations petitioned Parliament opposing compulsory purchase orders on public open spaces. The Secretary of State announced in July 1985 that he was introducing a bill to reverse the decision of a Joint Parliamentary Committee and confirm a route through the National Park. This was followed by a confirmation bill in November 1985 that was passed in the House of Lords on 5 December 1985. Construction started in November 1986 and the road was opened on 19 July 1988.",
"title": "History of the association"
},
{
"paragraph_id": 19,
"text": "The DPA continues to follow the same objectives as when it was founded. The activities have widened, involving local partners, it has a calendar of events, walks and work days with its Conservation Team undertaking a variety of moorland projects, it funds the supply of walking boots to some children who need them for the Duke of Edinburgh Award Scheme through the Moor Boots Scheme, it collaborates with the Campaign for National Parks, it monitors the activities of Dartmoor National Park Authority who run the National Park. It objected to eight planning proposals (with success in seven cases), with many other achievements in the DPA Director's Annual Report. The DPA remains true to its original objectives and has also added other activities in support of Dartmoor and its inhabitants.",
"title": "Since 2000"
},
{
"paragraph_id": 20,
"text": "The china clay industry on Dartmoor was established long before the DPA was founded. The earliest record of a china clay pit refers to Hook Lake in 1502. The area was surveyed around 1827 by Cornishmen with thirty years experience in the clay industry. They obtained a 21-year lease in 1830, from the Earl of Morley who owned the land, to work the area between Lee Moor and Shaugh Moor. A rival pit was opened at Leftlake in about 1850 and at Hemerdon and Broomage in about 1855. Further pits were opened at Cholwichtown, Whitehill Yeo and Wigford Down/Brisworthy (circa 1860). Others followed at Smallhanger and Headon in the 1870s. Redlake started working in 1910. China clay pits are open cast mines that result in large holes in the ground accompanied by large waste tips. Over time, the pits become larger and more ground is needed for the waste, changing the landscape: the effect of this can be seen from space.",
"title": "Since 2000"
},
{
"paragraph_id": 21,
"text": "The DPA argues that this is an activity that does not agree with the ethos of a National Park, whose purpose is to protect landscape from unsuitable development. In 1994, the National Park boundaries were changed to include common land at Shaugh Moor and exclude china clay worked land at Lee Moor. The DPA revived its campaign with the publication of a booklet in 1999 when the Blackabrook Valley, Crownhill Down and Shaugh Moor, near the popular tourist area of Cadover Bridge, all came under threat from exploitation or dumping of waste. The china clay companies relinquished planning permissions in 2001. However, in November 2009, the clay companies, Sibelco and Imerys, produced a report reviewing old mineral permissions under the Environment Act 1995 with a view to joining up two pits. A presumed Bronze Age barrow, known as Emmets Post, was to be removed and three other monuments may be affected. The DPA were recorded twice, with other bodies, in a Devon County Council Development Management Committee Report for their representations in securing the future of the three areas where planning permissions were relinquished in 2001. Oxford Archaeology held an open day during their excavation of Emmets Post in 2014 prior to its removal.",
"title": "Since 2000"
},
{
"paragraph_id": 22,
"text": "The DPA and Exmoor Society held a joint reception at the House of Lords on 6 November 2008, hosted by Baroness Mallalieu, to lobby members of both Houses of Parliament and relevant Ministers about ensuring that environmental schemes for the uplands are \"fit for purpose\". Both organisations funded an invited number of upland hill farmers to attend.",
"title": "Since 2000"
},
{
"paragraph_id": 23,
"text": "The excavation in August 2011 on the north moor of a Bronze Age burial kistvaen, or cist, that was originally uncovered in 2001 was part-funded by the DPA, along with other bodies.",
"title": "Since 2000"
},
{
"paragraph_id": 24,
"text": "A conference for the upland farmers of Bodmin Moor, Exmoor and Dartmoor was held as a joint venture between the South West Uplands Federation and the DPA. It was run by the DPA at Exeter Racecourse in October 2012, with 150 delegates. Speakers came from the Foundation for Common Land, the Forest of Dartmoor Commoners, the University of Gloucestershire, the National Farmers Union of England and Wales and the Open Spaces Society. The CEO raised sponsorship from Dartmoor National Park, Exmoor National Park, Natural England, Duchy of Cornwall and the Exmoor Society - this reflecting the standing of the DPA with those bodies.",
"title": "Since 2000"
},
{
"paragraph_id": 25,
"text": "Two major projects to underground overhead power cables in Dartmoor National Park have been completed in a joint project between Western Power Distribution, the South West Protected Landscapes Forum (SWPLF) and Dartmoor National Park Authority. The two schemes on Holne Moor and Walkhampton Common between them remove nearly 6 km of overhead line from open moorland. At nearly 5 km, the Walkhampton scheme is the largest to be undertaken in the South West region by Western Power Distribution. The old overhead line was readily visible from the B3212 Princetown to Yelverton Road, strung across Walkhampton Common from Devil's Elbow to just above Horseyeatt at Peek Hill. The works to provide the new underground supply were mainly undertaken on the highway to minimise the impact on the sensitive moorland landscape, its archaeology, wildlife and livestock. The DPA has supported the undergrounding of these visually intrusive power lines for many years.",
"title": "Since 2000"
},
{
"paragraph_id": 26,
"text": "The Dartmoor Conservation Garden is a joint project between DPA and Dartmoor National Park Authority (DNPA) and is located in the Jack Wigmore Garden behind the High Moorland Centre in Princetown: this is a memorial garden to a former Chair of the Authority. It is planted with a cross-section of typical native Dartmoor plants. It also houses some typical Dartmoor archaeological features, such as a 4,000-year-old Bronze Age burial kistvaen (or cist) and a Medieval granite cross from Ter Hill. This marked the Monk's Path but was constantly being pushed over by cattle. The purpose of the Garden is to illustrate the biodiversity on Dartmoor. The project came online in June 2015.",
"title": "Since 2000"
},
{
"paragraph_id": 27,
"text": "The DPA were involved in a campaign in June 2015 against four telecommunications masts planned for Dartmoor, with the first to be erected in the village of Widecombe. At short notice, the DPA banners were taken out, letters written, press interviews given and support given to the villagers when an inflatable mast was demonstrated – with the effect that the planning application was withdrawn.",
"title": "Since 2000"
},
{
"paragraph_id": 28,
"text": "In common with other amenity bodies, such as those for the Lake District, Peak District, Pembrokeshire Coast, Yorkshire Dales Three Peaks and the New Forest Trust, the image of Dartmoor Preservation Association is evolving from its Victorian origins, although the original name is being retained. Friends of Dartmoor projects a more modern image of preservation where several years of diplomacy have achieved good relations with the partner agencies that operate in the Dartmoor arena. This is due mainly to the efforts of the previous CEO, James Paxman and his successor, Phil Hutt.",
"title": "Since 2000"
},
{
"paragraph_id": 29,
"text": "The DPA Constitution, objectives and policies are published on the DPA web site.",
"title": "Since 2000"
},
{
"paragraph_id": 30,
"text": "The objectives enshrined in the constitution are the protection, preservation and enhancement in the public interest of the landscape, antiquities, flora and fauna, natural beauty, cultural heritage and scientific interest of Dartmoor. Also the protection and preservation of public access to and on Dartmoor subject to the ancient rights of commoners. Co-operation with the commoners and any organisation in achieving DPA objectives, also the study of and the recording and publication of information upon the antiquities, history and natural history of Dartmoor.",
"title": "Since 2000"
},
{
"paragraph_id": 31,
"text": "The DPA has twenty-two policies listed on its web site: regarding access and rights of way, fencing, protecting monuments, diverse habitats, bracken, china clay quarrying, military training and live firing, hill farming and small scale traditional local industries, quarrying, television and telephone masts, wind farms, planning applications, housing developments, woodlands and forestry, ponies, swaling, and recreational activities.",
"title": "Since 2000"
},
{
"paragraph_id": 32,
"text": "The DPA conservation team meet throughout the year to work on a number of ongoing projects; from gorse clearance, to habitat protection and archaeological surveying. A quarterly timetable is released both on the organisation's website and through its member publications, along with details of how to get involved. The team also host an annual open day at the DPA land holding of Pudsham Meadows.",
"title": "Since 2000"
}
] | 2002-02-25T15:51:15Z | 2023-12-21T14:54:29Z | [
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|
8,418 | Dartmouth College | Dartmouth College (/ˈdɑːrtməθ/; DART-məth) is a private Ivy League research university in Hanover, New Hampshire. Established in 1769 by Eleazar Wheelock, Dartmouth is one of the nine colonial colleges chartered before the American Revolution. It is among the most prestigious universities in the country.
Although originally established to educate Native Americans in Christian theology and the English way of life, the university primarily trained Congregationalist ministers during its early history before it gradually secularized. Emerging into national prominence at the turn of the 20th century, Dartmouth was considered to be the most prestigious undergraduate college in the United States in the early 1900s. While Dartmouth is now a research university rather than simply an undergraduate college, it continues to go by "Dartmouth College" to emphasize its focus on undergraduate education.
Following a liberal arts curriculum, Dartmouth provides undergraduate instruction in 40 academic departments and interdisciplinary programs, including 60 majors in the humanities, social sciences, natural sciences, and engineering, and enables students to design specialized concentrations or engage in dual degree programs. In addition to the undergraduate faculty of arts and sciences, Dartmouth has four professional and graduate schools: the Geisel School of Medicine, the Thayer School of Engineering, the Tuck School of Business, and the Guarini School of Graduate and Advanced Studies. The university also has affiliations with the Dartmouth–Hitchcock Medical Center. Dartmouth is home to the Rockefeller Center for Public Policy and the Social Sciences, the Hood Museum of Art, the John Sloan Dickey Center for International Understanding, and the Hopkins Center for the Arts. With a student enrollment of about 6,700, Dartmouth is the smallest university in the Ivy League. Undergraduate admissions are highly selective with an acceptance rate of 6% for the class of 2027, including a 4.5% rate for regular decision applicants.
Situated on a terrace above the Connecticut River, Dartmouth's 269-acre (109 ha) main campus is in the rural Upper Valley region of New England. The university functions on a quarter system, operating year-round on four ten-week academic terms. Dartmouth is known for its undergraduate focus, Greek culture, and campus traditions. Its 34 varsity sports teams compete intercollegiately in the Ivy League conference of the NCAA Division I. The university has many prominent alumni, including 170 members of the United States Congress, 24 U.S. governors, 8 U.S. Cabinet secretaries, 3 Nobel Prize laureates, 2 U.S. Supreme Court justices, and a U.S. vice president. Other notable alumni include 81 Rhodes Scholars, 26 Marshall Scholarship recipients, 13 Pulitzer Prize recipients, 10 CEOs of Fortune 500 companies, and 51 Olympic medalists.
Dartmouth was founded by Eleazar Wheelock, a Yale graduate and Congregational minister from Windham, Connecticut, who had sought to establish a school to train Native Americans as Christian missionaries. It was one of the nine colonial colleges chartered before the American Revolution. Wheelock's ostensible inspiration for such an establishment resulted from his relationship with Mohegan Indian Samson Occom. Occom became an ordained minister after studying under Wheelock from 1743 to 1747, and later moved to Long Island to preach to the Montauks.
Wheelock founded Moor's Indian Charity School in 1755. The Charity School proved somewhat successful, but additional funding was necessary to continue school's operations, and Wheelock sought the help of friends to raise money. The first major donation to the school was given by John Phillips in 1762, who would go on to found Phillips Exeter Academy. Occom, accompanied by the Reverend Nathaniel Whitaker, traveled to England in 1766 to raise money from churches. With these funds, they established a trust to help Wheelock. The head of the trust was a Methodist named William Legge, 2nd Earl of Dartmouth.
Although the fund provided Wheelock ample financial support for the Charity School, Wheelock initially had trouble recruiting Indians to the institution, primarily because its location was far from tribal territories. In seeking to expand the school into a college, Wheelock relocated it to Hanover, in the Province of New Hampshire. The move from Connecticut followed a lengthy and sometimes frustrating effort to find resources and secure a charter. The Royal Governor of New Hampshire, John Wentworth, provided the land upon which Dartmouth would be built and on December 13, 1769, issued a royal charter in the name of King George III establishing the college. That charter created a college "for the education and instruction of Youth of the Indian Tribes in this Land in reading, writing & all parts of Learning which shall appear necessary and expedient for civilizing & christianizing Children of Pagans as well as in all liberal Arts and Sciences and also of English Youth and any others". The reference to educating Native American youth was included to connect Dartmouth to the Charity School and enable the use of the Charity School's unspent trust funds. Named for William Legge, 2nd Earl of Dartmouth – an important supporter of Eleazar Wheelock's earlier efforts but who, in fact, opposed creation of the college and never donated to it – Dartmouth is the nation's ninth oldest college and the last institution of higher learning established under Colonial rule. The college granted its first degrees in 1771.
Given the limited success of the Charity School, however, Wheelock intended his new college as one primarily for whites. Occom, disappointed with Wheelock's departure from the school's original goal of Indian Christianization, went on to form his own community of New England Indians called Brothertown Indians in New York.
In 1819, Dartmouth College was the subject of the historic Dartmouth College case, which challenged New Hampshire's 1816 attempt to amend the college' charter to make the school a public university. An institution called Dartmouth University occupied the college buildings and began operating in Hanover in 1817, though the college continued teaching classes in rented rooms nearby. Daniel Webster, an alumnus of the class of 1801, presented the college's case to the Supreme Court, which found the amendment of Dartmouth's charter to be an illegal impairment of a contract by the state and reversed New Hampshire's takeover of the college. Webster concluded his peroration with the famous words: "It is, Sir, as I have said, a small college. And yet there are those who love it."
Dartmouth taught its first African-American students in 1775 and 1808. By the end of the Civil War, 20 black men had attended the college or its medical school. and Dartmouth "was recognized in the African-American community as a place where a man of color could go to get educated". One of them, Jonathan C. Gibbs, served as Secretary of State and Superintendent of Public Instruction for the state of Florida.
In 1866, the New Hampshire College of Agriculture and the Mechanic Arts was incorporated in Hanover, in connection with Dartmouth College. The institution was officially associated with Dartmouth and was directed by Dartmouth's president. The new college was moved to Durham, New Hampshire, in 1891, and later became known as the University of New Hampshire.
Dartmouth emerged onto the national academic stage at the turn of the 20th century. Prior to this period, the college had clung to traditional methods of instruction and was relatively poorly funded. Under President William Jewett Tucker (1893–1909), Dartmouth underwent a major revitalization of facilities, faculty, and the student body, following large endowments such as the $10,000 given by Dartmouth alumnus and law professor John Ordronaux. 20 new structures replaced antiquated buildings, while the student body and faculty both expanded threefold. Tucker is often credited for having "refounded Dartmouth" and bringing it into national prestige.
Presidents Ernest Fox Nichols (1909–16) and Ernest Martin Hopkins (1916–45) continued Tucker's trend of modernization, further improving campus facilities and introducing selective admissions in the 1920s. In 1945, Hopkins was subject to no small amount of controversy, as he openly admitted to Dartmouth's practice of using racial quotas to deny Jews entry into the university. John Sloan Dickey, serving as president from 1945 until 1970, strongly emphasized the liberal arts, particularly public policy and international relations. During World War II, Dartmouth was one of 131 colleges and universities nationally that took part in the V-12 Navy College Training Program which offered students a path to a navy commission.
The Dartmouth workshop, which was held in 1956, is widely considered to be the founding event of artificial intelligence as a field.
In 1970, longtime professor of mathematics and computer science John George Kemeny became president of Dartmouth. Kemeny oversaw several major changes at the college. Dartmouth, which had been a men's institution, began admitting women as full-time students and undergraduate degree candidates in 1972 amid much controversy. At about the same time, the college adopted its "Dartmouth Plan" of academic scheduling, permitting the student body to increase in size within the existing facilities. In 1988, Dartmouth's alma mater song's lyrics changed from "Men of Dartmouth" to "Dear old Dartmouth".
During the 1990s, the college saw a major academic overhaul under President James O. Freedman and a controversial (and ultimately unsuccessful) 1999 initiative to encourage the school's single-sex Greek houses to go coed. The first decade of the 21st century saw the commencement of the $1.5 billion Campaign for the Dartmouth Experience, the largest capital fundraising campaign in the college's history, which surpassed $1 billion in 2008. The mid- and late first decade of the 21st century have also seen extensive campus construction, with the erection of two new housing complexes, full renovation of two dormitories, and a forthcoming dining hall, life sciences center, and visual arts center. In 2004, Booz Allen Hamilton selected Dartmouth College as a model of institutional endurance "whose record of endurance has had implications and benefits for all American organizations, both academic and commercial", citing Dartmouth College v. Woodward and Dartmouth's successful self-reinvention in the late 19th century.
Since the election of a number of petition-nominated trustees to the Board of Trustees starting in 2004, the role of alumni in Dartmouth governance has been the subject of ongoing conflict. President James Wright announced his retirement in February 2008 and was replaced by Harvard University professor and physician Jim Yong Kim on July 1, 2009.
In May 2010 Dartmouth joined the Matariki Network of Universities (MNU) together with Durham University (UK), Queen's University (Canada), University of Otago (New Zealand), University of Tübingen (Germany), University of Western Australia (Australia) and Uppsala University (Sweden).
In early August 2019, Dartmouth College agreed to pay nine current and former students a total of $14 million to settle a class-action lawsuit alleging they were sexually harassed by three former neuroscience professors.
In 2019, Dartmouth College was elected to the Association of American Universities (AAU).
In April 2022, Dartmouth College returned the papers of Samson Occum (who helped Eleazar Wheelock secure the funds for Dartmouth College for what Occom believed would be a school for Native students in Connecticut) to the Mohegan Tribe.
In November 2022, Dartmouth Hall was rededicated after a $42 million renovation. Fundraising for the project was led by over 1700 alumnae as part of the celebration of 50 years of coeducation at Dartmouth College.
Dartmouth, a liberal arts institution, offers a four-year Bachelor of Arts and ABET-accredited Bachelor of Engineering degree to undergraduate students. The college has 39 academic departments offering 56 major programs, while students are free to design special majors or engage in dual majors. For the graduating class of 2017, the most popular majors were economics, government, computer science, engineering sciences, and history. The Economics Department, whose prominent professors include David Blanchflower and Andrew Samwick, also holds the distinction as the top-ranked bachelor's-only economics program in the world.
In order to graduate, a student must complete 35 total courses, eight to ten of which are typically part of a chosen major program. Other requirements for graduation include the completion of ten "distributive requirements" in a variety of academic fields, proficiency in a foreign language, and completion of a writing class and first-year seminar in writing. Many departments offer honors programs requiring students seeking that distinction to engage in "independent, sustained work", culminating in the production of a thesis. In addition to the courses offered in Hanover, Dartmouth offers 57 different off-campus programs, including Foreign Study Programs, Language Study Abroad programs, and Exchange Programs.
Through the Graduate Studies program, Dartmouth grants doctorate and master's degrees in 19 Arts & Sciences graduate programs. Although the first graduate degree, a PhD in classics, was awarded in 1885, many of the current PhD programs have only existed since the 1960s. Furthermore, Dartmouth is home to three professional schools: the Geisel School of Medicine (established 1797), Thayer School of Engineering (1867)—which also serves as the undergraduate department of engineering sciences—and Tuck School of Business (1900). With these professional schools and graduate programs, conventional American usage would accord Dartmouth the label of "Dartmouth University"; however, because of historical and nostalgic reasons (such as Dartmouth College v. Woodward), the school uses the name "Dartmouth College" to refer to the entire institution.
Dartmouth employs a total of 607 tenured or tenure-track faculty members, including the highest proportion of female tenured professors among the Ivy League universities, and the first black woman tenure-track faculty member in computer science at an Ivy League university. Faculty members have been at the forefront of such major academic developments as the Dartmouth Workshop, the Dartmouth Time Sharing System, Dartmouth BASIC, and Dartmouth ALGOL 30. In 2005, sponsored project awards to Dartmouth faculty research amounted to $169 million.
Dartmouth served as the host member of the University Press of New England, a university press founded in 1970 that included Brandeis University, Tufts University, the University of New Hampshire, and Northeastern University. The University Press of New England shut down in 2018. With the exception of Dartmouth College Press titles, in 2021, Brandeis become the sole owner of all copyrights and titles of UPNE.
Dartmouth was ranked 12th among undergraduate programs at national universities by U.S. News & World Report in its 2022 rankings. U.S. News also ranked the school 3rd best for veterans, tied for 5th best in undergraduate teaching, and 7th for "best value" national universities. Dartmouth's undergraduate teaching was previously ranked 1st by U.S. News for five years in a row (2009–2013). Dartmouth College is accredited by the New England Commission of Higher Education.
In Forbes' 2019 rankings of 650 universities, liberal arts colleges and service academies, Dartmouth ranked 10th overall and 10th in research universities. In the Forbes 2018 "grateful graduate" rankings, Dartmouth came in first for the second year in a row.
The 2021 Academic Ranking of World Universities ranked Dartmouth among the 90–110th best universities in the nation. However, this specific ranking has drawn criticism from scholars for not adequately adjusting for the size of an institution, which leads to larger institutions ranking above smaller ones like Dartmouth.
The 2006 Carnegie Foundation classification listed Dartmouth as the only "majority-undergraduate", "arts-and-sciences focus[ed]", "research university" in the country that also had "some graduate coexistence" and "very high research activity".
Undergraduate admission to Dartmouth College is characterized by the Carnegie Foundation and U.S. News & World Report as "most selective". The Princeton Review, in its 2023 edition, gave the university an admissions selectivity rating of 98 out of 99.
For the freshman class entering Fall 2023, Dartmouth received a record 28,841 applications of which 6.2% were accepted, consistent with the prior two years; approximately 67% of those accepted are expected to matriculate. Of those admitted students who reported class rank, 444 were ranked first or second in their class, while 96% ranked in the top decile. The admitted students' academic profile showed an all-time high SAT average score of 1501, while the average composite ACT score remained at 33.
Additionally, for the 2016–2017 academic year, Dartmouth received 685 transfer applications of which 5.1% were accepted, with an average SAT composite score of 1490, average composite ACT score of 34, and average college GPA of about 3.85. Dartmouth meets 100% of students' demonstrated financial need in order to attend the college, and currently admits all students, including internationals, on a need-blind basis.
Dartmouth guarantees to meet 100% of the demonstrated need of every admitted student who applies for financial aid at the time of admission. Dartmouth is one of seven American universities to practice international need-blind admissions. This means that all applicants, including U.S. permanent residents, undocumented students in the U.S., and international students, are admitted to the college without regard to their financial circumstances. At Dartmouth, free tuition is provided for students from families with total incomes of $125,000 or less and possessing typical assets. Dartmouth is also one of a few U.S. universities to eliminate undergraduate student loans and replace them with expanded scholarship grants. In 2015, $88.8 million (~$108 million in 2022) in need-based scholarships were awarded to Dartmouth students.
The median family income of Dartmouth students is $200,400, with 58% of students coming from the top 10% highest-earning families and 14% from the bottom 60%.
However, a 2022 article from The Dartmouth disputes the college's claims by saying the following: "To put it all together with the $9 million of student debt from the Class of 2021, this change in Dartmouth policy, hailed as "eliminat[ing] loans for undergraduate students" actually eliminated only about a quarter—27.4% to be exact—of student loans for undergraduate students. So, while Dartmouth gets glowing coverage in news publications across the country, 72.6% of the debt it saddles its students with remains."
Dartmouth functions on a quarter system, operating year-round on four ten-week academic terms. The Dartmouth Plan (or simply "D-Plan") is an academic scheduling system that permits the customization of each student's academic year. All undergraduates are required to be in residence for the fall, winter, and spring terms of their freshman year and two terms of their senior year, as well as the summer term of their sophomore year. However, students may petition to alter this plan so that they may be off during terms of their senior year or sophomore summer terms. During all terms, students are permitted to choose between studying on-campus, studying at an off-campus program, or taking a term off for vacation, outside internships, or research projects. The typical course load is three classes per term, and students will generally enroll in classes for 12 total terms over the course of their academic career.
The D-Plan was instituted in the early 1970s at the same time that Dartmouth began accepting female undergraduates. It was initially devised as a plan to increase the enrollment without enlarging campus accommodations, and has been described as "a way to put 4,000 students into 3,000 beds". Although new dormitories have been built since, the number of students has also increased and the D-Plan remains in effect. It was modified in the 1980s in an attempt to reduce the problems of lack of social and academic continuity.
Dartmouth is governed by a board of trustees comprising the college president (ex officio), the state governor (ex officio), 13 trustees nominated and elected by the board (called "charter trustees"), and eight trustees nominated by alumni and elected by the board ("alumni trustees"). The nominees for alumni trustee are determined by a poll of the members of the Association of Alumni of Dartmouth College, selecting from among names put forward by the Alumni Council or by alumni petition.
Although the board elected its members from the two sources of nominees in equal proportions between 1891 and 2007, the board decided in 2007 to add several new members, all charter trustees. In the controversy that followed the decision, the Association of Alumni filed a lawsuit, although it later withdrew the action. In 2008, the board added five new charter trustees.
This is what a college is supposed to look like.
—U.S. President Dwight D. Eisenhower, 1953
Dartmouth College is situated in the rural town of Hanover, New Hampshire, located in the Upper Valley along the Connecticut River in New England. Its 269-acre (1.09 km) campus is centered on a 5-acre (2 ha) "Green", a former field of pine trees cleared in 1771. Dartmouth is the largest private landowner of the town of Hanover, and its total landholdings and facilities are worth an estimated $434 million. In addition to its campus in Hanover, Dartmouth owns 4,500 acres (18 km) of Mount Moosilauke in the White Mountains and a 27,000-acre (110 km) tract of land in northern New Hampshire known as the Second College Grant.
Dartmouth's campus buildings vary in age from Wentworth and Thornton Halls of the 1820s (the oldest surviving buildings constructed by the college) to new dormitories and mathematics facilities completed in 2006. Most of Dartmouth's buildings are designed in the Georgian colonial architecture style, a theme which has been preserved in recent architectural additions. The college has actively sought to reduce carbon emissions and energy usage on campus, earning it the grade of A− from the Sustainable Endowments Institute on its College Sustainability Report Card 2008.
A notable feature of the Dartmouth campus is its many trees which (despite Dutch elm disease) include some 200 American elms. The campus also has the largest Kentucky coffeetree in New Hampshire, at 91 ft tall.
While Dartmouth's campus is located in a rural setting, it is connected to several major cities by intercity bus services that directly serve Dartmouth and Hanover. Dartmouth Coach provides service from Hanover to South Station and Logan International Airport in Boston as well as New York City, while Greyhound Lines operates a daily route connecting Hanover and Montreal. All three cities are popular weekend/vacation destinations for Dartmouth students.
The college's creative and performing arts facility is the Hopkins Center for the Arts ("the Hop"). Opened in 1962, the Hop houses the college's drama, music, film, and studio arts departments, as well as a woodshop, pottery studio, and jewelry studio which are open for use by students and faculty. The building was designed by the famed architect Wallace Harrison, who would later design the similar-looking façade of Manhattan's Metropolitan Opera House at Lincoln Center. Its facilities include two theaters and one 900-seat auditorium. The Hop is also the location of all student mailboxes ("Hinman boxes") and the Courtyard Café dining facility. The Hop is connected to the Hood Museum of Art, arguably North America's oldest museum in continuous operation, and the Loew Auditorium, where films are screened.
In addition to its 19 graduate programs in the arts and sciences, Dartmouth is home to three separate graduate schools. The Geisel School of Medicine is located in a complex on the north side of campus and includes laboratories, classrooms, offices, and a biomedical library. The Dartmouth–Hitchcock Medical Center, located several miles to the south in Lebanon, New Hampshire, contains a 396-bed teaching hospital for the Medical School. The Thayer School of Engineering and the Tuck School of Business are both located at the end of Tuck Mall, west of the center of campus and near the Connecticut River. The Thayer School comprises two buildings; Tuck has seven academic and administrative buildings, as well as several common areas. The two graduate schools share a library, the Feldberg Business & Engineering Library. In December 2018, Dartmouth began a major expansion of the west end of campus by breaking ground on the $200 million (~$231 million in 2022) Center for Engineering and Computer Science. The Center will house the Computer Science department and Magnuson Center for Entrepreneurship. In October 2019, construction began on the Irving Institute of Energy and Society. Both were completed by Spring 2022, and the Center for Engineering and Computer Science was renamed the Class of 1982 Engineering and Computer Science Center.
Dartmouth's libraries are all part of the collective Dartmouth College Library, which comprises 2.48 million volumes and 6 million total resources, including videos, maps, sound recordings, and photographs. Its specialized libraries include the Biomedical Libraries, Evans Map Room, Feldberg Business & Engineering Library, Jones Media Center, Rauner Special Collections Library, and Sherman Art Library. Baker-Berry Library is the main library at Dartmouth, consisting of a merger of the Baker Memorial Library (opened 1928) and the Berry Library (completed 2002). Located on the northern side of the Green, Baker's 200-foot (61 m) tower is an iconic symbol of the college.
Dartmouth's original sports field was the Green, where students played cricket and old division football during the 19th century. Today, two of Dartmouth's athletic facilities are located in the southeast corner of campus. The center of athletic life is the Alumni Gymnasium, which includes the Karl Michael Competition Pool and the Spaulding Pool, a fitness center, a weight room, and a 1/13th-mile (123 m) indoor track. Attached to Alumni Gymnasium is the Berry Sports Center, which contains basketball and volleyball courts (Leede Arena), as well as the Kresge Fitness Center. Behind the Alumni Gymnasium is Memorial Field, a 15,600-seat stadium overlooking Dartmouth's football field and track. The nearby Thompson Arena, designed by Italian engineer Pier Luigi Nervi and constructed in 1975, houses Dartmouth's ice rink. Also visible from Memorial Field is the 91,800-square-foot (8,530 m) Nathaniel Leverone Fieldhouse, home to the indoor track. The new softball field, Dartmouth Softball Park, was constructed in 2012, sharing parking facilities with Thompson arena and replacing Sachem Field, located over a mile from campus, as the primary softball facility.
Dartmouth's other athletic facilities in Hanover include the Friends of Dartmouth Rowing Boathouse and the old rowing house storage facility (both located along the Connecticut River), the Hanover Country Club, Dartmouth's oldest remaining athletic facility (established in 1899), and the Corey Ford Rugby Clubhouse. The college also maintains the Dartmouth Skiway, a 100-acre (0.40 km) skiing facility located over two mountains near the Hanover campus in Lyme Center, New Hampshire, that serves as the winter practice grounds for the Dartmouth ski team, which is a perennial contender for the NCAA Division I championship.
Dartmouth's close association and involvement in the development of the downhill skiing industry is featured in the 2010 book Passion for Skiing as well as the 2013 documentary based on the book Passion for Snow.
Beginning in the fall term of 2016, Dartmouth placed all undergraduate students in one of six House communities, similar to residential colleges, including Allen House, East Wheelock House, North Park House, School House, South House, and West House, alongside independent Living Learning Communities. Dartmouth used to have nine residential communities located throughout campus, instead of ungrouped dormitories or residential colleges. The dormitories varied in design from modern to traditional Georgian styles, and room arrangements range from singles to quads and apartment suites. Since 2006, the college has guaranteed housing for students during their freshman and sophomore years. More than 3,000 students elect to live in housing provided by college.
Campus meals are served by Dartmouth Dining Services, which operates 11 dining establishments around campus. The Class of 1953 Commons, commonly referred to as "Foco", is the all-you-can-eat dining hall, located at the center of campus. Dartmouth also operates à la carte cafes around campus (Collis Café, Courtyard Café, Novack Café, The Fern Coffee & Tea Bar, Ramekin, and Café@Baker), a convenience store (Collis Market), and 3 snack bars located in the Allen House Commons (also called the "Cube"), McLaughlin Cluster, and East Wheelock Cluster.
The Collis Center is the center of student life and programming, serving as what would be generically termed the "student union" or "campus center". It contains a café, study space, common areas, and a number of administrative departments, including the Academic Skills Center. Robinson Hall, next door to both the Collis Center and the Class of 1953 Commons, contains the offices of a number of student organizations, including the Dartmouth Outing Club and The Dartmouth daily newspaper.
Dartmouth Student Government represents students on issues related to student life. Annually, students elect a student body president, vice president, and undergraduate senate to represent them in the following academic year. In 2006, The Princeton Review ranked Dartmouth third in its "Quality of Life" category, and sixth for having the "Happiest Students". Athletics and participation in the Greek system are the most popular campus activities. In all, Dartmouth offers more than 350 organizations, teams, and sports. The school is also home to a variety of longstanding traditions and celebrations and has a loyal alumni network; Dartmouth ranked #2 in "The Princeton Review" in 2006 for Best Alumni Network.
In 2014, Dartmouth College was the third highest in the nation in "total of reports of rape" on their main campus, with 42 reports of rape. The Washington Post attributed the high number of rape reports to the fact that a growing number of sexual assault victims feel comfortable enough to report sexual assaults that would have gone unreported in previous years. In 2015, the Huffington Post reported that Dartmouth had the highest rate of bystander intervention of any college surveyed, with 57.7% of Dartmouth students reporting that they would take some sort of action if they saw someone acting in a "sexually violent or harassing manner," compared to 45.5% of students nationally.
Dartmouth fraternities have an extensive history of hazing and alcohol abuse, leading to police raids and accusations of sexual harassment.
Dartmouth's more than 200 student organizations and clubs cover a wide range of interests. In 2007, the college hosted eight academic groups, 17 cultural groups, two honor societies, 30 "issue-oriented" groups, 25 performing groups, 12 pre-professional groups, 20 publications, and 11 recreational groups. Notable student groups include the nation's largest and oldest collegiate outdoors club, the Dartmouth Outing Club, which includes the nationally recognized Big Green Bus; the campus's oldest a cappella group, The Dartmouth Aires; the controversial independent newspaper The Dartmouth Review; Dartmouth Student Government, the college's official undergraduate student government; and The Dartmouth, arguably the nation's oldest university newspaper. The Dartmouth describes itself as "America's Oldest College Newspaper, Founded 1799".
Partially because of Dartmouth's rural, isolated location, the Greek system dating from the 1840s is one of the most popular social outlets for students. Dartmouth is home to 32 recognized Greek houses: 17 fraternities, 12 sororities, and three coeducational organizations. In 2007, roughly 70% of eligible students belonged to a Greek organization; since 1987, students have not been permitted to join Greek organizations until their sophomore year. Dartmouth College was among the first institutions of higher education to desegregate fraternity houses, doing so in the 1950s, and was involved in the movement to create coeducational Greek houses in the 1970s. In the early first decade of the 21st century, campus-wide debate focused on a board of trustees recommendation that Greek organizations become "substantially coeducational"; this attempt to change the Greek system eventually failed.
Dartmouth also has a number of secret societies, which are student- and alumni-led organizations often focused on preserving the history of the college and initiating service projects. Most prominent among them is the Sphinx society, housed in a prominent Egyptian tomb-like building near the center of campus. The Sphinx has been the subject of numerous rumors as to its facilities, practices, and membership.
The college has an additional classification of social/residential organizations known as undergraduate societies.
Approximately 20% of students participate in a varsity sport, and nearly 80% participate in some form of club, varsity, intramural, or other athletics. In 2021, Dartmouth College fielded 33 intercollegiate varsity teams: 15 for men, 17 for women, and coeducational sailing and equestrian programs. Dartmouth's athletic teams compete in the NCAA Division I eight-member Ivy League conference; some teams also participate in the Eastern College Athletic Conference (ECAC). As is mandatory for the members of the Ivy League, Dartmouth College does not offer athletic scholarships. In addition to the traditional American team sports (football, basketball, baseball, and ice hockey), Dartmouth competes at the varsity level in many other sports including track and field, softball, squash, sailing, tennis, rowing, soccer, skiing, and lacrosse.
The college also offers 26 club and intramural sports such as fencing, rugby, water polo, figure skating, boxing, volleyball, ultimate frisbee, and cricket, leading to a 75% participation rate in athletics among the undergraduate student body. The Dartmouth Fencing Team, despite being entirely self-coached, won the USACFC club national championship in 2014. The Dartmouth Men's Rugby Team, founded in 1951, has been ranked among the best collegiate teams in that sport, winning for example the Ivy Rugby Conference every year between 2008 and 2020. The figure skating team won the national championship five straight times from 2004 through 2008. In addition to the academic requirements for graduation, Dartmouth requires every undergraduate to complete a 50-yard (46 m) swim and three terms of physical education.
The charter of Dartmouth College, granted to Wheelock in 1769, proclaims that the institution was created "for the education and instruction of Youth of the Indian Tribes in this Land in reading, writing and all parts of Learning ... as well as in all liberal Arts and Sciences; and also of English Youth and any others". However, Wheelock primarily intended the college to educate white youth, and the few Native students that attended Dartmouth experienced much difficulty in an institution ostensibly dedicated to their education. The funds for the Charity School for Native Americans that preceded Dartmouth College were raised primarily by the efforts of a Mohegan named Samson Occom, and at least some of those funds were used to help found the college.
The college graduated only 19 Native Americans during its first 200 years. In 1970, the college established Native American academic and social programs as part of a "new dedication to increasing Native American enrollment". Since then, Dartmouth has graduated over 700 Native American students from over 200 different tribes, more than the other seven Ivy League universities combined.
Dartmouth is well known for its fierce school spirit and many traditions. The college functions on a quarter system, and one weekend each term is set aside as a traditional celebratory event, known on campus as "big weekends" or "party weekends". In the fall term, Homecoming (officially called Dartmouth Night) is marked by a bonfire on the Green constructed by the freshman class. Winter term is celebrated by Winter Carnival, a tradition started in 1911 by the Dartmouth Outing Club to promote winter sports. This tradition is the oldest in the United States, and subsequently went on to catch on at other New England colleges. In the spring, Green Key is a weekend mostly devoted to campus parties and celebration.
The summer term was formerly marked by Tubestock, an unofficial tradition in which the students used wooden rafts and inner tubes to float on the Connecticut River. Begun in 1986, Tubestock was ended in 2006 by town ordinance. The Class of 2008, during their summer term on campus in 2006, replaced the defunct Tubestock with Fieldstock. This new celebration includes a barbecue, live music, and the revival of the 1970s and 1980s tradition of racing homemade chariots around the Green. Unlike Tubestock, Fieldstock is funded and supported by the college.
Another longstanding tradition is four-day, student-run First-Year Trips for incoming freshmen, begun in 1935. Each trip concludes at the Moosilauke Ravine Lodge. In 2011, over 96% of freshmen elected to participate.
Dartmouth's motto, chosen by Eleazar Wheelock, is Vox clamantis in deserto. The Latin motto is literally translated as "The voice of one crying in the wilderness", but is more often rendered as "A voice crying out in the wilderness". The phrase appears five times in the Bible and is a reference to the college's location on what was once the frontier of European settlement. Richard Hovey's "Men of Dartmouth" was elected as the best of Dartmouth's songs in 1896, and became the school's official song in 1926. The song was retitled to "Alma Mater" in the 1980s when its lyrics were changed to refer to women as well as men.
Dartmouth's 1769 royal charter required the creation of a seal for use on official documents and diplomas. The college's founder, Eleazar Wheelock, designed a seal for his college bearing a striking resemblance to the seal of the Society for the Propagation of the Gospel, a missionary society founded in London in 1701, in order to maintain the illusion that his college was more for mission work than for higher education. Engraved by a Boston silversmith, the seal was ready by commencement of 1773. The trustees officially accepted the seal on August 25, 1773, describing it as:
An Oval, circumscribed by a Line containing SIGILL: COL: DARTMUTH: NOV: HANT: IN AMERICA 1770. within projecting a Pine Grove on the Right, whence proceed Natives towards an Edifice two Storey on the left; which bears in a Label over the Grove these Words "vox clamantis in deserto" the whole supported by Religion on the Right and Justice on the Left, and bearing in a Triangle irradiate, with the Hebrew Words [El Shaddai], agreeable to the above Impression, be the common Seal under which to pass all Diplomas or Certificates of Degrees, and all other Affairs of Business of and concerning Dartmouth College.
On October 28, 1926, the trustees affirmed the charter's reservation of the seal for official corporate documents alone. The College Publications Committee commissioned noted typographer William Addison Dwiggins to create a line drawing version of the seal in 1940 that saw widespread use. Dwiggins' design was modified during 1957 to change the date from "1770" to "1769", to accord with the date of the college charter. The trustees commissioned a new set of dies with a date of "1769" to replace the old dies, now badly worn after almost two hundred years of use. The 1957 design continues to be used under trademark number 2305032.
On October 28, 1926, the trustees approved a "Dartmouth College Shield" for general use. Artist and engraver W. Parke Johnson designed this emblem on the basis of the shield that is depicted at the center of the original seal. This design does not survive. On June 9, 1944, the trustees approved another coat of arms based on the shield part of the seal, this one by Canadian artist and designer Thoreau MacDonald. That design was used widely and, like Dwiggins' seal, had its date changed from "1770" to "1769" around 1958. That version continues to be used under trademark registration number 3112676 and others.
College designer John Scotford made a stylized version of the shield during the 1960s, but it did not see the success of MacDonald's design. The shield appears to have been used as the basis of the shield of the Geisel School of Medicine, and it has been reproduced in sizes as small as 20 micrometers across. The design has appeared on Rudolph Ruzicka's Bicentennial Medal (Philadelphia Mint, 1969) and elsewhere.
Dartmouth has never had an official mascot. The nickname "The Big Green", originating in the 1860s, is based on students' adoption of a shade of forest green ("Dartmouth Green") as the school's official color in 1866. Beginning in the 1920s, the Dartmouth College athletic teams were known by their unofficial nickname "the Indians", a moniker that probably originated among sports journalists. This unofficial mascot and team name was used until the early 1970s, when its use came under criticism. In 1974, the Trustees declared the "use of the [Indian] symbol in any form to be inconsistent with present institutional and academic objectives of the College in advancing Native American education". Some alumni and students, as well as the conservative student newspaper, The Dartmouth Review, have sought to return the Indian symbol to prominence, but never succeeded in doing so.
Various student initiatives have been undertaken to adopt a mascot, but none has become "official". One proposal devised by the college humor magazine the Dartmouth Jack-O-Lantern was Keggy the Keg, an anthropomorphic beer keg who makes occasional appearances at college sporting events. Despite student enthusiasm for Keggy, the mascot has received approval from only the student government. In November 2006, student government attempted to revive the "Dartmoose" as a potential replacement amid renewed controversy surrounding the former unofficial Indian mascot.
Dartmouth's alumni are known for frequently donating to their alma mater. Most start by giving to the Senior Class Gift. According to a 2008 article in The Wall Street Journal based on data from payscale.com, Dartmouth graduates also earn higher median salaries at least 10 years after graduation than alumni of any other American university surveyed.
By 2008, Dartmouth had graduated 238 classes of students, and had over 60,000 living alumni in a variety of fields. Finance, consulting, and technology have consistently been the most popular industries to enter for students. Top employers of new graduates include Goldman Sachs, Morgan Stanley, McKinsey & Company, Bain & Company, Amazon, Microsoft, and Google.
Nelson A. Rockefeller, 41st Vice President of the United States and 49th Governor of New York, graduated cum laude from Dartmouth with a degree in economics in 1930. Over 164 Dartmouth graduates have served in the United States Senate and United States House of Representatives, such as Massachusetts statesman Daniel Webster. Cabinet members of American presidents include Attorney General Amos T. Akerman, Secretary of Defense James V. Forrestal, Secretary of Labor Robert Reich, Secretary of the Treasury Henry Paulson, and Secretary of the Treasury Timothy Geithner. C. Everett Koop was the Surgeon General of the United States under President Ronald Reagan. Two Dartmouth alumni have served as justices on the Supreme Court of the United States: Salmon P. Chase and Levi Woodbury. Eugene Norman Veasey (class of 1954) served as the Chief Justice of Delaware. The 46th Governor of Pennsylvania, Tom Wolf; the 42nd Governor of Illinois, businessman Bruce Rauner; and the 31st governor and current senator from North Dakota, John Hoeven (R), are also Dartmouth alumni. Ernesto de la Guardia, class of 1925, was president of the Republic of Panama.
In literature and journalism, Dartmouth has produced 13 Pulitzer Prize winners: Thomas M. Burton, Richard Eberhart, Dan Fagin, Paul Gigot, Frank Gilroy, Jake Hooker, Nigel Jaquiss, Joseph Rago, Martin J. Sherwin, David K. Shipler, David Shribman, Justin Harvey Smith and Robert Frost. Frost, who received four Pulitzer Prizes for Poetry in his lifetime, attended but did not graduate from Dartmouth; he is, however, the only person to have received two honorary degrees from Dartmouth.
Other authors and media personalities include CNN Chief White House correspondent and anchor Jake Tapper, novelist and founding editor of The Believer Heidi Julavits, "Dean of rock critics" Robert Christgau, National Book Award winners Louise Erdrich and Phil Klay, novelist/screenwriter Budd Schulberg, political commentator Dinesh D'Souza, radio talk show host Laura Ingraham, commentator Mort Kondracke, and journalist James Panero. Norman Maclean, professor at the University of Chicago and author of A River Runs Through It and Other Stories, graduated from Dartmouth in 1924. Theodor Geisel, better known as children's author Dr. Seuss, was a member of the class of 1925.
In the area of religion and theology, Dartmouth alumni include priests and ministers Ebenezer Porter, Jonathan Clarkson Gibbs, Caleb Sprague Henry, Arthur Whipple Jenks, Solomon Spalding, and Joseph Tracy; and rabbis Marshall Meyer, Arnold Resnicoff, and David E. Stern. Hyrum Smith, brother of Mormon Prophet Joseph Smith, attended the college in his teens. He was Patriarch of the LDS Church.
Dartmouth alumni in academia include Stuart Kauffman and Jeffrey Weeks, both recipients of MacArthur Fellowships (commonly called "genius grants"). Dartmouth has also graduated three Nobel Prize winners with four separate prizes: Owen Chamberlain (Physics, 1959), K. Barry Sharpless (Chemistry, 2001 and 2022), and George Davis Snell (Physiology or Medicine, 1980). Educators include founder and first president of Bates College Oren Burbank Cheney (1839); the former chancellor of the University of California, San Diego, Marye Anne Fox (PhD. in Chemistry, 1974); founding president of Vassar College Milo Parker Jewett; founder and first president of Kenyon College Philander Chase; first professor of Wabash College Caleb Mills; president of Union College Charles Augustus Aiken. Nine of Dartmouth's 17 presidents were alumni of the college.
Dartmouth alumni serving as CEOs or company presidents and executives include Charles Alfred Pillsbury, founder of the Pillsbury Company and patriarch of the Pillsbury family, Sandy Alderson (San Diego Padres), John Donahoe (eBay), Louis V. Gerstner, Jr. (IBM), Charles E. Haldeman (Putnam Investments), Donald J. Hall Sr. (Hallmark Cards), Douglas Hodge (CEO of PIMCO accused of fraud), Jeffrey R. Immelt (General Electric), Gail Koziara Boudreaux (United Health Care), Grant Tinker (NBC), Greg Maffei (Liberty Media), and Brian Goldner (Hasbro).
In film, entertainment, and television, Dartmouth is represented by David Benioff, co-creator, showrunner, and writer of Game of Thrones; Shonda Rhimes, creator of Grey's Anatomy, Private Practice, and Scandal; Budd Schulberg, Academy Award-winning screenwriter of On the Waterfront; Michael Phillips, who won the Academy Award for Best Picture as co-producer of The Sting; Rachel Dratch, a former cast member of Saturday Night Live; Chris Meledandri, executive producer of Ice Age, Horton Hears a Who!, and Despicable Me; writer and director duo Phil Lord and Chris Miller; and the title character of Mister Rogers' Neighborhood, Fred Rogers. Other notable film and television figures include Sarah Wayne Callies (Prison Break), Emmy Award winner Michael Moriarty, Andrew Shue of Melrose Place, Aisha Tyler of Friends and 24, ESPN and Tennis Channel broadcaster Brett Haber, Connie Britton of Spin City and Friday Night Lights, Mindy Kaling of The Office and The Mindy Project, David Harbour of Stranger Things, and Michelle Khare of HBO Max's Karma.
A number of Dartmouth alumni have found success in professional sports. In baseball, Dartmouth alumni include All-Star and three-time Gold Glove winner and manager Brad Ausmus, All-Star reliever Mike Remlinger, and pitcher Kyle Hendricks. Professional football players include Miami Dolphins quarterback Jay Fiedler, linebacker Reggie Williams, three-time Pro Bowler Nick Lowery, quarterback Jeff Kemp, and Tennessee Titans tight end Casey Cramer, and Miami Dolphins defensive coordinator Matt Burke. Dartmouth has also produced a number of Olympic competitors. Adam Nelson won the silver medal in the shot put in the 2000 Sydney Olympics and the gold medal at the 2004 Athens Olympics to go along with his gold medal in the 2005 World Championships in Athletics in Helsinki. Kristin King and Sarah Parsons were members of the United States' 2006 bronze medal-winning ice hockey team. Cherie Piper, Gillian Apps, and Katie Weatherston were among Canada's ice hockey gold medalists in 2006. Lawrence Whitney won bronze at the 1912 Summer Olympics in men's shot put.
Dick Durrance and Tim Caldwell competed for the United States in skiing in the 1936 and 1976 Winter Olympics, respectively. Arthur Shaw, Earl Thomson, Edwin Myers, Marc Wright, Adam Nelson, Gerry Ashworth, and Vilhjálmur Einarsson have all won medals in track and field events. Former heavyweight rower Dominic Seiterle is a member of the Canadian national rowing team and won a gold medal at the 2008 Summer Olympics in the men's 8+ event.
Dartmouth College has appeared in or been referenced by a number of popular media. Some of the most prominent include: | [
{
"paragraph_id": 0,
"text": "Dartmouth College (/ˈdɑːrtməθ/; DART-məth) is a private Ivy League research university in Hanover, New Hampshire. Established in 1769 by Eleazar Wheelock, Dartmouth is one of the nine colonial colleges chartered before the American Revolution. It is among the most prestigious universities in the country.",
"title": ""
},
{
"paragraph_id": 1,
"text": "Although originally established to educate Native Americans in Christian theology and the English way of life, the university primarily trained Congregationalist ministers during its early history before it gradually secularized. Emerging into national prominence at the turn of the 20th century, Dartmouth was considered to be the most prestigious undergraduate college in the United States in the early 1900s. While Dartmouth is now a research university rather than simply an undergraduate college, it continues to go by \"Dartmouth College\" to emphasize its focus on undergraduate education.",
"title": ""
},
{
"paragraph_id": 2,
"text": "Following a liberal arts curriculum, Dartmouth provides undergraduate instruction in 40 academic departments and interdisciplinary programs, including 60 majors in the humanities, social sciences, natural sciences, and engineering, and enables students to design specialized concentrations or engage in dual degree programs. In addition to the undergraduate faculty of arts and sciences, Dartmouth has four professional and graduate schools: the Geisel School of Medicine, the Thayer School of Engineering, the Tuck School of Business, and the Guarini School of Graduate and Advanced Studies. The university also has affiliations with the Dartmouth–Hitchcock Medical Center. Dartmouth is home to the Rockefeller Center for Public Policy and the Social Sciences, the Hood Museum of Art, the John Sloan Dickey Center for International Understanding, and the Hopkins Center for the Arts. With a student enrollment of about 6,700, Dartmouth is the smallest university in the Ivy League. Undergraduate admissions are highly selective with an acceptance rate of 6% for the class of 2027, including a 4.5% rate for regular decision applicants.",
"title": ""
},
{
"paragraph_id": 3,
"text": "Situated on a terrace above the Connecticut River, Dartmouth's 269-acre (109 ha) main campus is in the rural Upper Valley region of New England. The university functions on a quarter system, operating year-round on four ten-week academic terms. Dartmouth is known for its undergraduate focus, Greek culture, and campus traditions. Its 34 varsity sports teams compete intercollegiately in the Ivy League conference of the NCAA Division I. The university has many prominent alumni, including 170 members of the United States Congress, 24 U.S. governors, 8 U.S. Cabinet secretaries, 3 Nobel Prize laureates, 2 U.S. Supreme Court justices, and a U.S. vice president. Other notable alumni include 81 Rhodes Scholars, 26 Marshall Scholarship recipients, 13 Pulitzer Prize recipients, 10 CEOs of Fortune 500 companies, and 51 Olympic medalists.",
"title": ""
},
{
"paragraph_id": 4,
"text": "Dartmouth was founded by Eleazar Wheelock, a Yale graduate and Congregational minister from Windham, Connecticut, who had sought to establish a school to train Native Americans as Christian missionaries. It was one of the nine colonial colleges chartered before the American Revolution. Wheelock's ostensible inspiration for such an establishment resulted from his relationship with Mohegan Indian Samson Occom. Occom became an ordained minister after studying under Wheelock from 1743 to 1747, and later moved to Long Island to preach to the Montauks.",
"title": "History"
},
{
"paragraph_id": 5,
"text": "Wheelock founded Moor's Indian Charity School in 1755. The Charity School proved somewhat successful, but additional funding was necessary to continue school's operations, and Wheelock sought the help of friends to raise money. The first major donation to the school was given by John Phillips in 1762, who would go on to found Phillips Exeter Academy. Occom, accompanied by the Reverend Nathaniel Whitaker, traveled to England in 1766 to raise money from churches. With these funds, they established a trust to help Wheelock. The head of the trust was a Methodist named William Legge, 2nd Earl of Dartmouth.",
"title": "History"
},
{
"paragraph_id": 6,
"text": "Although the fund provided Wheelock ample financial support for the Charity School, Wheelock initially had trouble recruiting Indians to the institution, primarily because its location was far from tribal territories. In seeking to expand the school into a college, Wheelock relocated it to Hanover, in the Province of New Hampshire. The move from Connecticut followed a lengthy and sometimes frustrating effort to find resources and secure a charter. The Royal Governor of New Hampshire, John Wentworth, provided the land upon which Dartmouth would be built and on December 13, 1769, issued a royal charter in the name of King George III establishing the college. That charter created a college \"for the education and instruction of Youth of the Indian Tribes in this Land in reading, writing & all parts of Learning which shall appear necessary and expedient for civilizing & christianizing Children of Pagans as well as in all liberal Arts and Sciences and also of English Youth and any others\". The reference to educating Native American youth was included to connect Dartmouth to the Charity School and enable the use of the Charity School's unspent trust funds. Named for William Legge, 2nd Earl of Dartmouth – an important supporter of Eleazar Wheelock's earlier efforts but who, in fact, opposed creation of the college and never donated to it – Dartmouth is the nation's ninth oldest college and the last institution of higher learning established under Colonial rule. The college granted its first degrees in 1771.",
"title": "History"
},
{
"paragraph_id": 7,
"text": "Given the limited success of the Charity School, however, Wheelock intended his new college as one primarily for whites. Occom, disappointed with Wheelock's departure from the school's original goal of Indian Christianization, went on to form his own community of New England Indians called Brothertown Indians in New York.",
"title": "History"
},
{
"paragraph_id": 8,
"text": "In 1819, Dartmouth College was the subject of the historic Dartmouth College case, which challenged New Hampshire's 1816 attempt to amend the college' charter to make the school a public university. An institution called Dartmouth University occupied the college buildings and began operating in Hanover in 1817, though the college continued teaching classes in rented rooms nearby. Daniel Webster, an alumnus of the class of 1801, presented the college's case to the Supreme Court, which found the amendment of Dartmouth's charter to be an illegal impairment of a contract by the state and reversed New Hampshire's takeover of the college. Webster concluded his peroration with the famous words: \"It is, Sir, as I have said, a small college. And yet there are those who love it.\"",
"title": "History"
},
{
"paragraph_id": 9,
"text": "Dartmouth taught its first African-American students in 1775 and 1808. By the end of the Civil War, 20 black men had attended the college or its medical school. and Dartmouth \"was recognized in the African-American community as a place where a man of color could go to get educated\". One of them, Jonathan C. Gibbs, served as Secretary of State and Superintendent of Public Instruction for the state of Florida.",
"title": "History"
},
{
"paragraph_id": 10,
"text": "In 1866, the New Hampshire College of Agriculture and the Mechanic Arts was incorporated in Hanover, in connection with Dartmouth College. The institution was officially associated with Dartmouth and was directed by Dartmouth's president. The new college was moved to Durham, New Hampshire, in 1891, and later became known as the University of New Hampshire.",
"title": "History"
},
{
"paragraph_id": 11,
"text": "Dartmouth emerged onto the national academic stage at the turn of the 20th century. Prior to this period, the college had clung to traditional methods of instruction and was relatively poorly funded. Under President William Jewett Tucker (1893–1909), Dartmouth underwent a major revitalization of facilities, faculty, and the student body, following large endowments such as the $10,000 given by Dartmouth alumnus and law professor John Ordronaux. 20 new structures replaced antiquated buildings, while the student body and faculty both expanded threefold. Tucker is often credited for having \"refounded Dartmouth\" and bringing it into national prestige.",
"title": "History"
},
{
"paragraph_id": 12,
"text": "Presidents Ernest Fox Nichols (1909–16) and Ernest Martin Hopkins (1916–45) continued Tucker's trend of modernization, further improving campus facilities and introducing selective admissions in the 1920s. In 1945, Hopkins was subject to no small amount of controversy, as he openly admitted to Dartmouth's practice of using racial quotas to deny Jews entry into the university. John Sloan Dickey, serving as president from 1945 until 1970, strongly emphasized the liberal arts, particularly public policy and international relations. During World War II, Dartmouth was one of 131 colleges and universities nationally that took part in the V-12 Navy College Training Program which offered students a path to a navy commission.",
"title": "History"
},
{
"paragraph_id": 13,
"text": "The Dartmouth workshop, which was held in 1956, is widely considered to be the founding event of artificial intelligence as a field.",
"title": "History"
},
{
"paragraph_id": 14,
"text": "In 1970, longtime professor of mathematics and computer science John George Kemeny became president of Dartmouth. Kemeny oversaw several major changes at the college. Dartmouth, which had been a men's institution, began admitting women as full-time students and undergraduate degree candidates in 1972 amid much controversy. At about the same time, the college adopted its \"Dartmouth Plan\" of academic scheduling, permitting the student body to increase in size within the existing facilities. In 1988, Dartmouth's alma mater song's lyrics changed from \"Men of Dartmouth\" to \"Dear old Dartmouth\".",
"title": "History"
},
{
"paragraph_id": 15,
"text": "During the 1990s, the college saw a major academic overhaul under President James O. Freedman and a controversial (and ultimately unsuccessful) 1999 initiative to encourage the school's single-sex Greek houses to go coed. The first decade of the 21st century saw the commencement of the $1.5 billion Campaign for the Dartmouth Experience, the largest capital fundraising campaign in the college's history, which surpassed $1 billion in 2008. The mid- and late first decade of the 21st century have also seen extensive campus construction, with the erection of two new housing complexes, full renovation of two dormitories, and a forthcoming dining hall, life sciences center, and visual arts center. In 2004, Booz Allen Hamilton selected Dartmouth College as a model of institutional endurance \"whose record of endurance has had implications and benefits for all American organizations, both academic and commercial\", citing Dartmouth College v. Woodward and Dartmouth's successful self-reinvention in the late 19th century.",
"title": "History"
},
{
"paragraph_id": 16,
"text": "Since the election of a number of petition-nominated trustees to the Board of Trustees starting in 2004, the role of alumni in Dartmouth governance has been the subject of ongoing conflict. President James Wright announced his retirement in February 2008 and was replaced by Harvard University professor and physician Jim Yong Kim on July 1, 2009.",
"title": "History"
},
{
"paragraph_id": 17,
"text": "In May 2010 Dartmouth joined the Matariki Network of Universities (MNU) together with Durham University (UK), Queen's University (Canada), University of Otago (New Zealand), University of Tübingen (Germany), University of Western Australia (Australia) and Uppsala University (Sweden).",
"title": "History"
},
{
"paragraph_id": 18,
"text": "In early August 2019, Dartmouth College agreed to pay nine current and former students a total of $14 million to settle a class-action lawsuit alleging they were sexually harassed by three former neuroscience professors.",
"title": "History"
},
{
"paragraph_id": 19,
"text": "In 2019, Dartmouth College was elected to the Association of American Universities (AAU).",
"title": "History"
},
{
"paragraph_id": 20,
"text": "In April 2022, Dartmouth College returned the papers of Samson Occum (who helped Eleazar Wheelock secure the funds for Dartmouth College for what Occom believed would be a school for Native students in Connecticut) to the Mohegan Tribe.",
"title": "History"
},
{
"paragraph_id": 21,
"text": "In November 2022, Dartmouth Hall was rededicated after a $42 million renovation. Fundraising for the project was led by over 1700 alumnae as part of the celebration of 50 years of coeducation at Dartmouth College.",
"title": "History"
},
{
"paragraph_id": 22,
"text": "Dartmouth, a liberal arts institution, offers a four-year Bachelor of Arts and ABET-accredited Bachelor of Engineering degree to undergraduate students. The college has 39 academic departments offering 56 major programs, while students are free to design special majors or engage in dual majors. For the graduating class of 2017, the most popular majors were economics, government, computer science, engineering sciences, and history. The Economics Department, whose prominent professors include David Blanchflower and Andrew Samwick, also holds the distinction as the top-ranked bachelor's-only economics program in the world.",
"title": "Academics"
},
{
"paragraph_id": 23,
"text": "In order to graduate, a student must complete 35 total courses, eight to ten of which are typically part of a chosen major program. Other requirements for graduation include the completion of ten \"distributive requirements\" in a variety of academic fields, proficiency in a foreign language, and completion of a writing class and first-year seminar in writing. Many departments offer honors programs requiring students seeking that distinction to engage in \"independent, sustained work\", culminating in the production of a thesis. In addition to the courses offered in Hanover, Dartmouth offers 57 different off-campus programs, including Foreign Study Programs, Language Study Abroad programs, and Exchange Programs.",
"title": "Academics"
},
{
"paragraph_id": 24,
"text": "Through the Graduate Studies program, Dartmouth grants doctorate and master's degrees in 19 Arts & Sciences graduate programs. Although the first graduate degree, a PhD in classics, was awarded in 1885, many of the current PhD programs have only existed since the 1960s. Furthermore, Dartmouth is home to three professional schools: the Geisel School of Medicine (established 1797), Thayer School of Engineering (1867)—which also serves as the undergraduate department of engineering sciences—and Tuck School of Business (1900). With these professional schools and graduate programs, conventional American usage would accord Dartmouth the label of \"Dartmouth University\"; however, because of historical and nostalgic reasons (such as Dartmouth College v. Woodward), the school uses the name \"Dartmouth College\" to refer to the entire institution.",
"title": "Academics"
},
{
"paragraph_id": 25,
"text": "Dartmouth employs a total of 607 tenured or tenure-track faculty members, including the highest proportion of female tenured professors among the Ivy League universities, and the first black woman tenure-track faculty member in computer science at an Ivy League university. Faculty members have been at the forefront of such major academic developments as the Dartmouth Workshop, the Dartmouth Time Sharing System, Dartmouth BASIC, and Dartmouth ALGOL 30. In 2005, sponsored project awards to Dartmouth faculty research amounted to $169 million.",
"title": "Academics"
},
{
"paragraph_id": 26,
"text": "Dartmouth served as the host member of the University Press of New England, a university press founded in 1970 that included Brandeis University, Tufts University, the University of New Hampshire, and Northeastern University. The University Press of New England shut down in 2018. With the exception of Dartmouth College Press titles, in 2021, Brandeis become the sole owner of all copyrights and titles of UPNE.",
"title": "Academics"
},
{
"paragraph_id": 27,
"text": "Dartmouth was ranked 12th among undergraduate programs at national universities by U.S. News & World Report in its 2022 rankings. U.S. News also ranked the school 3rd best for veterans, tied for 5th best in undergraduate teaching, and 7th for \"best value\" national universities. Dartmouth's undergraduate teaching was previously ranked 1st by U.S. News for five years in a row (2009–2013). Dartmouth College is accredited by the New England Commission of Higher Education.",
"title": "Academics"
},
{
"paragraph_id": 28,
"text": "In Forbes' 2019 rankings of 650 universities, liberal arts colleges and service academies, Dartmouth ranked 10th overall and 10th in research universities. In the Forbes 2018 \"grateful graduate\" rankings, Dartmouth came in first for the second year in a row.",
"title": "Academics"
},
{
"paragraph_id": 29,
"text": "The 2021 Academic Ranking of World Universities ranked Dartmouth among the 90–110th best universities in the nation. However, this specific ranking has drawn criticism from scholars for not adequately adjusting for the size of an institution, which leads to larger institutions ranking above smaller ones like Dartmouth.",
"title": "Academics"
},
{
"paragraph_id": 30,
"text": "The 2006 Carnegie Foundation classification listed Dartmouth as the only \"majority-undergraduate\", \"arts-and-sciences focus[ed]\", \"research university\" in the country that also had \"some graduate coexistence\" and \"very high research activity\".",
"title": "Academics"
},
{
"paragraph_id": 31,
"text": "Undergraduate admission to Dartmouth College is characterized by the Carnegie Foundation and U.S. News & World Report as \"most selective\". The Princeton Review, in its 2023 edition, gave the university an admissions selectivity rating of 98 out of 99.",
"title": "Academics"
},
{
"paragraph_id": 32,
"text": "For the freshman class entering Fall 2023, Dartmouth received a record 28,841 applications of which 6.2% were accepted, consistent with the prior two years; approximately 67% of those accepted are expected to matriculate. Of those admitted students who reported class rank, 444 were ranked first or second in their class, while 96% ranked in the top decile. The admitted students' academic profile showed an all-time high SAT average score of 1501, while the average composite ACT score remained at 33.",
"title": "Academics"
},
{
"paragraph_id": 33,
"text": "Additionally, for the 2016–2017 academic year, Dartmouth received 685 transfer applications of which 5.1% were accepted, with an average SAT composite score of 1490, average composite ACT score of 34, and average college GPA of about 3.85. Dartmouth meets 100% of students' demonstrated financial need in order to attend the college, and currently admits all students, including internationals, on a need-blind basis.",
"title": "Academics"
},
{
"paragraph_id": 34,
"text": "Dartmouth guarantees to meet 100% of the demonstrated need of every admitted student who applies for financial aid at the time of admission. Dartmouth is one of seven American universities to practice international need-blind admissions. This means that all applicants, including U.S. permanent residents, undocumented students in the U.S., and international students, are admitted to the college without regard to their financial circumstances. At Dartmouth, free tuition is provided for students from families with total incomes of $125,000 or less and possessing typical assets. Dartmouth is also one of a few U.S. universities to eliminate undergraduate student loans and replace them with expanded scholarship grants. In 2015, $88.8 million (~$108 million in 2022) in need-based scholarships were awarded to Dartmouth students.",
"title": "Academics"
},
{
"paragraph_id": 35,
"text": "The median family income of Dartmouth students is $200,400, with 58% of students coming from the top 10% highest-earning families and 14% from the bottom 60%.",
"title": "Academics"
},
{
"paragraph_id": 36,
"text": "However, a 2022 article from The Dartmouth disputes the college's claims by saying the following: \"To put it all together with the $9 million of student debt from the Class of 2021, this change in Dartmouth policy, hailed as \"eliminat[ing] loans for undergraduate students\" actually eliminated only about a quarter—27.4% to be exact—of student loans for undergraduate students. So, while Dartmouth gets glowing coverage in news publications across the country, 72.6% of the debt it saddles its students with remains.\"",
"title": "Academics"
},
{
"paragraph_id": 37,
"text": "Dartmouth functions on a quarter system, operating year-round on four ten-week academic terms. The Dartmouth Plan (or simply \"D-Plan\") is an academic scheduling system that permits the customization of each student's academic year. All undergraduates are required to be in residence for the fall, winter, and spring terms of their freshman year and two terms of their senior year, as well as the summer term of their sophomore year. However, students may petition to alter this plan so that they may be off during terms of their senior year or sophomore summer terms. During all terms, students are permitted to choose between studying on-campus, studying at an off-campus program, or taking a term off for vacation, outside internships, or research projects. The typical course load is three classes per term, and students will generally enroll in classes for 12 total terms over the course of their academic career.",
"title": "Academics"
},
{
"paragraph_id": 38,
"text": "The D-Plan was instituted in the early 1970s at the same time that Dartmouth began accepting female undergraduates. It was initially devised as a plan to increase the enrollment without enlarging campus accommodations, and has been described as \"a way to put 4,000 students into 3,000 beds\". Although new dormitories have been built since, the number of students has also increased and the D-Plan remains in effect. It was modified in the 1980s in an attempt to reduce the problems of lack of social and academic continuity.",
"title": "Academics"
},
{
"paragraph_id": 39,
"text": "Dartmouth is governed by a board of trustees comprising the college president (ex officio), the state governor (ex officio), 13 trustees nominated and elected by the board (called \"charter trustees\"), and eight trustees nominated by alumni and elected by the board (\"alumni trustees\"). The nominees for alumni trustee are determined by a poll of the members of the Association of Alumni of Dartmouth College, selecting from among names put forward by the Alumni Council or by alumni petition.",
"title": "Academics"
},
{
"paragraph_id": 40,
"text": "Although the board elected its members from the two sources of nominees in equal proportions between 1891 and 2007, the board decided in 2007 to add several new members, all charter trustees. In the controversy that followed the decision, the Association of Alumni filed a lawsuit, although it later withdrew the action. In 2008, the board added five new charter trustees.",
"title": "Academics"
},
{
"paragraph_id": 41,
"text": "This is what a college is supposed to look like.",
"title": "Campus"
},
{
"paragraph_id": 42,
"text": "—U.S. President Dwight D. Eisenhower, 1953",
"title": "Campus"
},
{
"paragraph_id": 43,
"text": "Dartmouth College is situated in the rural town of Hanover, New Hampshire, located in the Upper Valley along the Connecticut River in New England. Its 269-acre (1.09 km) campus is centered on a 5-acre (2 ha) \"Green\", a former field of pine trees cleared in 1771. Dartmouth is the largest private landowner of the town of Hanover, and its total landholdings and facilities are worth an estimated $434 million. In addition to its campus in Hanover, Dartmouth owns 4,500 acres (18 km) of Mount Moosilauke in the White Mountains and a 27,000-acre (110 km) tract of land in northern New Hampshire known as the Second College Grant.",
"title": "Campus"
},
{
"paragraph_id": 44,
"text": "Dartmouth's campus buildings vary in age from Wentworth and Thornton Halls of the 1820s (the oldest surviving buildings constructed by the college) to new dormitories and mathematics facilities completed in 2006. Most of Dartmouth's buildings are designed in the Georgian colonial architecture style, a theme which has been preserved in recent architectural additions. The college has actively sought to reduce carbon emissions and energy usage on campus, earning it the grade of A− from the Sustainable Endowments Institute on its College Sustainability Report Card 2008.",
"title": "Campus"
},
{
"paragraph_id": 45,
"text": "A notable feature of the Dartmouth campus is its many trees which (despite Dutch elm disease) include some 200 American elms. The campus also has the largest Kentucky coffeetree in New Hampshire, at 91 ft tall.",
"title": "Campus"
},
{
"paragraph_id": 46,
"text": "While Dartmouth's campus is located in a rural setting, it is connected to several major cities by intercity bus services that directly serve Dartmouth and Hanover. Dartmouth Coach provides service from Hanover to South Station and Logan International Airport in Boston as well as New York City, while Greyhound Lines operates a daily route connecting Hanover and Montreal. All three cities are popular weekend/vacation destinations for Dartmouth students.",
"title": "Campus"
},
{
"paragraph_id": 47,
"text": "The college's creative and performing arts facility is the Hopkins Center for the Arts (\"the Hop\"). Opened in 1962, the Hop houses the college's drama, music, film, and studio arts departments, as well as a woodshop, pottery studio, and jewelry studio which are open for use by students and faculty. The building was designed by the famed architect Wallace Harrison, who would later design the similar-looking façade of Manhattan's Metropolitan Opera House at Lincoln Center. Its facilities include two theaters and one 900-seat auditorium. The Hop is also the location of all student mailboxes (\"Hinman boxes\") and the Courtyard Café dining facility. The Hop is connected to the Hood Museum of Art, arguably North America's oldest museum in continuous operation, and the Loew Auditorium, where films are screened.",
"title": "Campus"
},
{
"paragraph_id": 48,
"text": "In addition to its 19 graduate programs in the arts and sciences, Dartmouth is home to three separate graduate schools. The Geisel School of Medicine is located in a complex on the north side of campus and includes laboratories, classrooms, offices, and a biomedical library. The Dartmouth–Hitchcock Medical Center, located several miles to the south in Lebanon, New Hampshire, contains a 396-bed teaching hospital for the Medical School. The Thayer School of Engineering and the Tuck School of Business are both located at the end of Tuck Mall, west of the center of campus and near the Connecticut River. The Thayer School comprises two buildings; Tuck has seven academic and administrative buildings, as well as several common areas. The two graduate schools share a library, the Feldberg Business & Engineering Library. In December 2018, Dartmouth began a major expansion of the west end of campus by breaking ground on the $200 million (~$231 million in 2022) Center for Engineering and Computer Science. The Center will house the Computer Science department and Magnuson Center for Entrepreneurship. In October 2019, construction began on the Irving Institute of Energy and Society. Both were completed by Spring 2022, and the Center for Engineering and Computer Science was renamed the Class of 1982 Engineering and Computer Science Center.",
"title": "Campus"
},
{
"paragraph_id": 49,
"text": "Dartmouth's libraries are all part of the collective Dartmouth College Library, which comprises 2.48 million volumes and 6 million total resources, including videos, maps, sound recordings, and photographs. Its specialized libraries include the Biomedical Libraries, Evans Map Room, Feldberg Business & Engineering Library, Jones Media Center, Rauner Special Collections Library, and Sherman Art Library. Baker-Berry Library is the main library at Dartmouth, consisting of a merger of the Baker Memorial Library (opened 1928) and the Berry Library (completed 2002). Located on the northern side of the Green, Baker's 200-foot (61 m) tower is an iconic symbol of the college.",
"title": "Campus"
},
{
"paragraph_id": 50,
"text": "Dartmouth's original sports field was the Green, where students played cricket and old division football during the 19th century. Today, two of Dartmouth's athletic facilities are located in the southeast corner of campus. The center of athletic life is the Alumni Gymnasium, which includes the Karl Michael Competition Pool and the Spaulding Pool, a fitness center, a weight room, and a 1/13th-mile (123 m) indoor track. Attached to Alumni Gymnasium is the Berry Sports Center, which contains basketball and volleyball courts (Leede Arena), as well as the Kresge Fitness Center. Behind the Alumni Gymnasium is Memorial Field, a 15,600-seat stadium overlooking Dartmouth's football field and track. The nearby Thompson Arena, designed by Italian engineer Pier Luigi Nervi and constructed in 1975, houses Dartmouth's ice rink. Also visible from Memorial Field is the 91,800-square-foot (8,530 m) Nathaniel Leverone Fieldhouse, home to the indoor track. The new softball field, Dartmouth Softball Park, was constructed in 2012, sharing parking facilities with Thompson arena and replacing Sachem Field, located over a mile from campus, as the primary softball facility.",
"title": "Campus"
},
{
"paragraph_id": 51,
"text": "Dartmouth's other athletic facilities in Hanover include the Friends of Dartmouth Rowing Boathouse and the old rowing house storage facility (both located along the Connecticut River), the Hanover Country Club, Dartmouth's oldest remaining athletic facility (established in 1899), and the Corey Ford Rugby Clubhouse. The college also maintains the Dartmouth Skiway, a 100-acre (0.40 km) skiing facility located over two mountains near the Hanover campus in Lyme Center, New Hampshire, that serves as the winter practice grounds for the Dartmouth ski team, which is a perennial contender for the NCAA Division I championship.",
"title": "Campus"
},
{
"paragraph_id": 52,
"text": "Dartmouth's close association and involvement in the development of the downhill skiing industry is featured in the 2010 book Passion for Skiing as well as the 2013 documentary based on the book Passion for Snow.",
"title": "Campus"
},
{
"paragraph_id": 53,
"text": "Beginning in the fall term of 2016, Dartmouth placed all undergraduate students in one of six House communities, similar to residential colleges, including Allen House, East Wheelock House, North Park House, School House, South House, and West House, alongside independent Living Learning Communities. Dartmouth used to have nine residential communities located throughout campus, instead of ungrouped dormitories or residential colleges. The dormitories varied in design from modern to traditional Georgian styles, and room arrangements range from singles to quads and apartment suites. Since 2006, the college has guaranteed housing for students during their freshman and sophomore years. More than 3,000 students elect to live in housing provided by college.",
"title": "Campus"
},
{
"paragraph_id": 54,
"text": "Campus meals are served by Dartmouth Dining Services, which operates 11 dining establishments around campus. The Class of 1953 Commons, commonly referred to as \"Foco\", is the all-you-can-eat dining hall, located at the center of campus. Dartmouth also operates à la carte cafes around campus (Collis Café, Courtyard Café, Novack Café, The Fern Coffee & Tea Bar, Ramekin, and Café@Baker), a convenience store (Collis Market), and 3 snack bars located in the Allen House Commons (also called the \"Cube\"), McLaughlin Cluster, and East Wheelock Cluster.",
"title": "Campus"
},
{
"paragraph_id": 55,
"text": "The Collis Center is the center of student life and programming, serving as what would be generically termed the \"student union\" or \"campus center\". It contains a café, study space, common areas, and a number of administrative departments, including the Academic Skills Center. Robinson Hall, next door to both the Collis Center and the Class of 1953 Commons, contains the offices of a number of student organizations, including the Dartmouth Outing Club and The Dartmouth daily newspaper.",
"title": "Campus"
},
{
"paragraph_id": 56,
"text": "Dartmouth Student Government represents students on issues related to student life. Annually, students elect a student body president, vice president, and undergraduate senate to represent them in the following academic year. In 2006, The Princeton Review ranked Dartmouth third in its \"Quality of Life\" category, and sixth for having the \"Happiest Students\". Athletics and participation in the Greek system are the most popular campus activities. In all, Dartmouth offers more than 350 organizations, teams, and sports. The school is also home to a variety of longstanding traditions and celebrations and has a loyal alumni network; Dartmouth ranked #2 in \"The Princeton Review\" in 2006 for Best Alumni Network.",
"title": "Student life"
},
{
"paragraph_id": 57,
"text": "In 2014, Dartmouth College was the third highest in the nation in \"total of reports of rape\" on their main campus, with 42 reports of rape. The Washington Post attributed the high number of rape reports to the fact that a growing number of sexual assault victims feel comfortable enough to report sexual assaults that would have gone unreported in previous years. In 2015, the Huffington Post reported that Dartmouth had the highest rate of bystander intervention of any college surveyed, with 57.7% of Dartmouth students reporting that they would take some sort of action if they saw someone acting in a \"sexually violent or harassing manner,\" compared to 45.5% of students nationally.",
"title": "Student life"
},
{
"paragraph_id": 58,
"text": "Dartmouth fraternities have an extensive history of hazing and alcohol abuse, leading to police raids and accusations of sexual harassment.",
"title": "Student life"
},
{
"paragraph_id": 59,
"text": "Dartmouth's more than 200 student organizations and clubs cover a wide range of interests. In 2007, the college hosted eight academic groups, 17 cultural groups, two honor societies, 30 \"issue-oriented\" groups, 25 performing groups, 12 pre-professional groups, 20 publications, and 11 recreational groups. Notable student groups include the nation's largest and oldest collegiate outdoors club, the Dartmouth Outing Club, which includes the nationally recognized Big Green Bus; the campus's oldest a cappella group, The Dartmouth Aires; the controversial independent newspaper The Dartmouth Review; Dartmouth Student Government, the college's official undergraduate student government; and The Dartmouth, arguably the nation's oldest university newspaper. The Dartmouth describes itself as \"America's Oldest College Newspaper, Founded 1799\".",
"title": "Student life"
},
{
"paragraph_id": 60,
"text": "Partially because of Dartmouth's rural, isolated location, the Greek system dating from the 1840s is one of the most popular social outlets for students. Dartmouth is home to 32 recognized Greek houses: 17 fraternities, 12 sororities, and three coeducational organizations. In 2007, roughly 70% of eligible students belonged to a Greek organization; since 1987, students have not been permitted to join Greek organizations until their sophomore year. Dartmouth College was among the first institutions of higher education to desegregate fraternity houses, doing so in the 1950s, and was involved in the movement to create coeducational Greek houses in the 1970s. In the early first decade of the 21st century, campus-wide debate focused on a board of trustees recommendation that Greek organizations become \"substantially coeducational\"; this attempt to change the Greek system eventually failed.",
"title": "Student life"
},
{
"paragraph_id": 61,
"text": "Dartmouth also has a number of secret societies, which are student- and alumni-led organizations often focused on preserving the history of the college and initiating service projects. Most prominent among them is the Sphinx society, housed in a prominent Egyptian tomb-like building near the center of campus. The Sphinx has been the subject of numerous rumors as to its facilities, practices, and membership.",
"title": "Student life"
},
{
"paragraph_id": 62,
"text": "The college has an additional classification of social/residential organizations known as undergraduate societies.",
"title": "Student life"
},
{
"paragraph_id": 63,
"text": "Approximately 20% of students participate in a varsity sport, and nearly 80% participate in some form of club, varsity, intramural, or other athletics. In 2021, Dartmouth College fielded 33 intercollegiate varsity teams: 15 for men, 17 for women, and coeducational sailing and equestrian programs. Dartmouth's athletic teams compete in the NCAA Division I eight-member Ivy League conference; some teams also participate in the Eastern College Athletic Conference (ECAC). As is mandatory for the members of the Ivy League, Dartmouth College does not offer athletic scholarships. In addition to the traditional American team sports (football, basketball, baseball, and ice hockey), Dartmouth competes at the varsity level in many other sports including track and field, softball, squash, sailing, tennis, rowing, soccer, skiing, and lacrosse.",
"title": "Student life"
},
{
"paragraph_id": 64,
"text": "The college also offers 26 club and intramural sports such as fencing, rugby, water polo, figure skating, boxing, volleyball, ultimate frisbee, and cricket, leading to a 75% participation rate in athletics among the undergraduate student body. The Dartmouth Fencing Team, despite being entirely self-coached, won the USACFC club national championship in 2014. The Dartmouth Men's Rugby Team, founded in 1951, has been ranked among the best collegiate teams in that sport, winning for example the Ivy Rugby Conference every year between 2008 and 2020. The figure skating team won the national championship five straight times from 2004 through 2008. In addition to the academic requirements for graduation, Dartmouth requires every undergraduate to complete a 50-yard (46 m) swim and three terms of physical education.",
"title": "Student life"
},
{
"paragraph_id": 65,
"text": "The charter of Dartmouth College, granted to Wheelock in 1769, proclaims that the institution was created \"for the education and instruction of Youth of the Indian Tribes in this Land in reading, writing and all parts of Learning ... as well as in all liberal Arts and Sciences; and also of English Youth and any others\". However, Wheelock primarily intended the college to educate white youth, and the few Native students that attended Dartmouth experienced much difficulty in an institution ostensibly dedicated to their education. The funds for the Charity School for Native Americans that preceded Dartmouth College were raised primarily by the efforts of a Mohegan named Samson Occom, and at least some of those funds were used to help found the college.",
"title": "Student life"
},
{
"paragraph_id": 66,
"text": "The college graduated only 19 Native Americans during its first 200 years. In 1970, the college established Native American academic and social programs as part of a \"new dedication to increasing Native American enrollment\". Since then, Dartmouth has graduated over 700 Native American students from over 200 different tribes, more than the other seven Ivy League universities combined.",
"title": "Student life"
},
{
"paragraph_id": 67,
"text": "Dartmouth is well known for its fierce school spirit and many traditions. The college functions on a quarter system, and one weekend each term is set aside as a traditional celebratory event, known on campus as \"big weekends\" or \"party weekends\". In the fall term, Homecoming (officially called Dartmouth Night) is marked by a bonfire on the Green constructed by the freshman class. Winter term is celebrated by Winter Carnival, a tradition started in 1911 by the Dartmouth Outing Club to promote winter sports. This tradition is the oldest in the United States, and subsequently went on to catch on at other New England colleges. In the spring, Green Key is a weekend mostly devoted to campus parties and celebration.",
"title": "Student life"
},
{
"paragraph_id": 68,
"text": "The summer term was formerly marked by Tubestock, an unofficial tradition in which the students used wooden rafts and inner tubes to float on the Connecticut River. Begun in 1986, Tubestock was ended in 2006 by town ordinance. The Class of 2008, during their summer term on campus in 2006, replaced the defunct Tubestock with Fieldstock. This new celebration includes a barbecue, live music, and the revival of the 1970s and 1980s tradition of racing homemade chariots around the Green. Unlike Tubestock, Fieldstock is funded and supported by the college.",
"title": "Student life"
},
{
"paragraph_id": 69,
"text": "Another longstanding tradition is four-day, student-run First-Year Trips for incoming freshmen, begun in 1935. Each trip concludes at the Moosilauke Ravine Lodge. In 2011, over 96% of freshmen elected to participate.",
"title": "Student life"
},
{
"paragraph_id": 70,
"text": "Dartmouth's motto, chosen by Eleazar Wheelock, is Vox clamantis in deserto. The Latin motto is literally translated as \"The voice of one crying in the wilderness\", but is more often rendered as \"A voice crying out in the wilderness\". The phrase appears five times in the Bible and is a reference to the college's location on what was once the frontier of European settlement. Richard Hovey's \"Men of Dartmouth\" was elected as the best of Dartmouth's songs in 1896, and became the school's official song in 1926. The song was retitled to \"Alma Mater\" in the 1980s when its lyrics were changed to refer to women as well as men.",
"title": "Insignia and other representations"
},
{
"paragraph_id": 71,
"text": "Dartmouth's 1769 royal charter required the creation of a seal for use on official documents and diplomas. The college's founder, Eleazar Wheelock, designed a seal for his college bearing a striking resemblance to the seal of the Society for the Propagation of the Gospel, a missionary society founded in London in 1701, in order to maintain the illusion that his college was more for mission work than for higher education. Engraved by a Boston silversmith, the seal was ready by commencement of 1773. The trustees officially accepted the seal on August 25, 1773, describing it as:",
"title": "Insignia and other representations"
},
{
"paragraph_id": 72,
"text": "An Oval, circumscribed by a Line containing SIGILL: COL: DARTMUTH: NOV: HANT: IN AMERICA 1770. within projecting a Pine Grove on the Right, whence proceed Natives towards an Edifice two Storey on the left; which bears in a Label over the Grove these Words \"vox clamantis in deserto\" the whole supported by Religion on the Right and Justice on the Left, and bearing in a Triangle irradiate, with the Hebrew Words [El Shaddai], agreeable to the above Impression, be the common Seal under which to pass all Diplomas or Certificates of Degrees, and all other Affairs of Business of and concerning Dartmouth College.",
"title": "Insignia and other representations"
},
{
"paragraph_id": 73,
"text": "On October 28, 1926, the trustees affirmed the charter's reservation of the seal for official corporate documents alone. The College Publications Committee commissioned noted typographer William Addison Dwiggins to create a line drawing version of the seal in 1940 that saw widespread use. Dwiggins' design was modified during 1957 to change the date from \"1770\" to \"1769\", to accord with the date of the college charter. The trustees commissioned a new set of dies with a date of \"1769\" to replace the old dies, now badly worn after almost two hundred years of use. The 1957 design continues to be used under trademark number 2305032.",
"title": "Insignia and other representations"
},
{
"paragraph_id": 74,
"text": "On October 28, 1926, the trustees approved a \"Dartmouth College Shield\" for general use. Artist and engraver W. Parke Johnson designed this emblem on the basis of the shield that is depicted at the center of the original seal. This design does not survive. On June 9, 1944, the trustees approved another coat of arms based on the shield part of the seal, this one by Canadian artist and designer Thoreau MacDonald. That design was used widely and, like Dwiggins' seal, had its date changed from \"1770\" to \"1769\" around 1958. That version continues to be used under trademark registration number 3112676 and others.",
"title": "Insignia and other representations"
},
{
"paragraph_id": 75,
"text": "College designer John Scotford made a stylized version of the shield during the 1960s, but it did not see the success of MacDonald's design. The shield appears to have been used as the basis of the shield of the Geisel School of Medicine, and it has been reproduced in sizes as small as 20 micrometers across. The design has appeared on Rudolph Ruzicka's Bicentennial Medal (Philadelphia Mint, 1969) and elsewhere.",
"title": "Insignia and other representations"
},
{
"paragraph_id": 76,
"text": "Dartmouth has never had an official mascot. The nickname \"The Big Green\", originating in the 1860s, is based on students' adoption of a shade of forest green (\"Dartmouth Green\") as the school's official color in 1866. Beginning in the 1920s, the Dartmouth College athletic teams were known by their unofficial nickname \"the Indians\", a moniker that probably originated among sports journalists. This unofficial mascot and team name was used until the early 1970s, when its use came under criticism. In 1974, the Trustees declared the \"use of the [Indian] symbol in any form to be inconsistent with present institutional and academic objectives of the College in advancing Native American education\". Some alumni and students, as well as the conservative student newspaper, The Dartmouth Review, have sought to return the Indian symbol to prominence, but never succeeded in doing so.",
"title": "Insignia and other representations"
},
{
"paragraph_id": 77,
"text": "Various student initiatives have been undertaken to adopt a mascot, but none has become \"official\". One proposal devised by the college humor magazine the Dartmouth Jack-O-Lantern was Keggy the Keg, an anthropomorphic beer keg who makes occasional appearances at college sporting events. Despite student enthusiasm for Keggy, the mascot has received approval from only the student government. In November 2006, student government attempted to revive the \"Dartmoose\" as a potential replacement amid renewed controversy surrounding the former unofficial Indian mascot.",
"title": "Insignia and other representations"
},
{
"paragraph_id": 78,
"text": "Dartmouth's alumni are known for frequently donating to their alma mater. Most start by giving to the Senior Class Gift. According to a 2008 article in The Wall Street Journal based on data from payscale.com, Dartmouth graduates also earn higher median salaries at least 10 years after graduation than alumni of any other American university surveyed.",
"title": "Alumni"
},
{
"paragraph_id": 79,
"text": "By 2008, Dartmouth had graduated 238 classes of students, and had over 60,000 living alumni in a variety of fields. Finance, consulting, and technology have consistently been the most popular industries to enter for students. Top employers of new graduates include Goldman Sachs, Morgan Stanley, McKinsey & Company, Bain & Company, Amazon, Microsoft, and Google.",
"title": "Alumni"
},
{
"paragraph_id": 80,
"text": "Nelson A. Rockefeller, 41st Vice President of the United States and 49th Governor of New York, graduated cum laude from Dartmouth with a degree in economics in 1930. Over 164 Dartmouth graduates have served in the United States Senate and United States House of Representatives, such as Massachusetts statesman Daniel Webster. Cabinet members of American presidents include Attorney General Amos T. Akerman, Secretary of Defense James V. Forrestal, Secretary of Labor Robert Reich, Secretary of the Treasury Henry Paulson, and Secretary of the Treasury Timothy Geithner. C. Everett Koop was the Surgeon General of the United States under President Ronald Reagan. Two Dartmouth alumni have served as justices on the Supreme Court of the United States: Salmon P. Chase and Levi Woodbury. Eugene Norman Veasey (class of 1954) served as the Chief Justice of Delaware. The 46th Governor of Pennsylvania, Tom Wolf; the 42nd Governor of Illinois, businessman Bruce Rauner; and the 31st governor and current senator from North Dakota, John Hoeven (R), are also Dartmouth alumni. Ernesto de la Guardia, class of 1925, was president of the Republic of Panama.",
"title": "Alumni"
},
{
"paragraph_id": 81,
"text": "In literature and journalism, Dartmouth has produced 13 Pulitzer Prize winners: Thomas M. Burton, Richard Eberhart, Dan Fagin, Paul Gigot, Frank Gilroy, Jake Hooker, Nigel Jaquiss, Joseph Rago, Martin J. Sherwin, David K. Shipler, David Shribman, Justin Harvey Smith and Robert Frost. Frost, who received four Pulitzer Prizes for Poetry in his lifetime, attended but did not graduate from Dartmouth; he is, however, the only person to have received two honorary degrees from Dartmouth.",
"title": "Alumni"
},
{
"paragraph_id": 82,
"text": "Other authors and media personalities include CNN Chief White House correspondent and anchor Jake Tapper, novelist and founding editor of The Believer Heidi Julavits, \"Dean of rock critics\" Robert Christgau, National Book Award winners Louise Erdrich and Phil Klay, novelist/screenwriter Budd Schulberg, political commentator Dinesh D'Souza, radio talk show host Laura Ingraham, commentator Mort Kondracke, and journalist James Panero. Norman Maclean, professor at the University of Chicago and author of A River Runs Through It and Other Stories, graduated from Dartmouth in 1924. Theodor Geisel, better known as children's author Dr. Seuss, was a member of the class of 1925.",
"title": "Alumni"
},
{
"paragraph_id": 83,
"text": "In the area of religion and theology, Dartmouth alumni include priests and ministers Ebenezer Porter, Jonathan Clarkson Gibbs, Caleb Sprague Henry, Arthur Whipple Jenks, Solomon Spalding, and Joseph Tracy; and rabbis Marshall Meyer, Arnold Resnicoff, and David E. Stern. Hyrum Smith, brother of Mormon Prophet Joseph Smith, attended the college in his teens. He was Patriarch of the LDS Church.",
"title": "Alumni"
},
{
"paragraph_id": 84,
"text": "Dartmouth alumni in academia include Stuart Kauffman and Jeffrey Weeks, both recipients of MacArthur Fellowships (commonly called \"genius grants\"). Dartmouth has also graduated three Nobel Prize winners with four separate prizes: Owen Chamberlain (Physics, 1959), K. Barry Sharpless (Chemistry, 2001 and 2022), and George Davis Snell (Physiology or Medicine, 1980). Educators include founder and first president of Bates College Oren Burbank Cheney (1839); the former chancellor of the University of California, San Diego, Marye Anne Fox (PhD. in Chemistry, 1974); founding president of Vassar College Milo Parker Jewett; founder and first president of Kenyon College Philander Chase; first professor of Wabash College Caleb Mills; president of Union College Charles Augustus Aiken. Nine of Dartmouth's 17 presidents were alumni of the college.",
"title": "Alumni"
},
{
"paragraph_id": 85,
"text": "Dartmouth alumni serving as CEOs or company presidents and executives include Charles Alfred Pillsbury, founder of the Pillsbury Company and patriarch of the Pillsbury family, Sandy Alderson (San Diego Padres), John Donahoe (eBay), Louis V. Gerstner, Jr. (IBM), Charles E. Haldeman (Putnam Investments), Donald J. Hall Sr. (Hallmark Cards), Douglas Hodge (CEO of PIMCO accused of fraud), Jeffrey R. Immelt (General Electric), Gail Koziara Boudreaux (United Health Care), Grant Tinker (NBC), Greg Maffei (Liberty Media), and Brian Goldner (Hasbro).",
"title": "Alumni"
},
{
"paragraph_id": 86,
"text": "In film, entertainment, and television, Dartmouth is represented by David Benioff, co-creator, showrunner, and writer of Game of Thrones; Shonda Rhimes, creator of Grey's Anatomy, Private Practice, and Scandal; Budd Schulberg, Academy Award-winning screenwriter of On the Waterfront; Michael Phillips, who won the Academy Award for Best Picture as co-producer of The Sting; Rachel Dratch, a former cast member of Saturday Night Live; Chris Meledandri, executive producer of Ice Age, Horton Hears a Who!, and Despicable Me; writer and director duo Phil Lord and Chris Miller; and the title character of Mister Rogers' Neighborhood, Fred Rogers. Other notable film and television figures include Sarah Wayne Callies (Prison Break), Emmy Award winner Michael Moriarty, Andrew Shue of Melrose Place, Aisha Tyler of Friends and 24, ESPN and Tennis Channel broadcaster Brett Haber, Connie Britton of Spin City and Friday Night Lights, Mindy Kaling of The Office and The Mindy Project, David Harbour of Stranger Things, and Michelle Khare of HBO Max's Karma.",
"title": "Alumni"
},
{
"paragraph_id": 87,
"text": "A number of Dartmouth alumni have found success in professional sports. In baseball, Dartmouth alumni include All-Star and three-time Gold Glove winner and manager Brad Ausmus, All-Star reliever Mike Remlinger, and pitcher Kyle Hendricks. Professional football players include Miami Dolphins quarterback Jay Fiedler, linebacker Reggie Williams, three-time Pro Bowler Nick Lowery, quarterback Jeff Kemp, and Tennessee Titans tight end Casey Cramer, and Miami Dolphins defensive coordinator Matt Burke. Dartmouth has also produced a number of Olympic competitors. Adam Nelson won the silver medal in the shot put in the 2000 Sydney Olympics and the gold medal at the 2004 Athens Olympics to go along with his gold medal in the 2005 World Championships in Athletics in Helsinki. Kristin King and Sarah Parsons were members of the United States' 2006 bronze medal-winning ice hockey team. Cherie Piper, Gillian Apps, and Katie Weatherston were among Canada's ice hockey gold medalists in 2006. Lawrence Whitney won bronze at the 1912 Summer Olympics in men's shot put.",
"title": "Alumni"
},
{
"paragraph_id": 88,
"text": "Dick Durrance and Tim Caldwell competed for the United States in skiing in the 1936 and 1976 Winter Olympics, respectively. Arthur Shaw, Earl Thomson, Edwin Myers, Marc Wright, Adam Nelson, Gerry Ashworth, and Vilhjálmur Einarsson have all won medals in track and field events. Former heavyweight rower Dominic Seiterle is a member of the Canadian national rowing team and won a gold medal at the 2008 Summer Olympics in the men's 8+ event.",
"title": "Alumni"
},
{
"paragraph_id": 89,
"text": "Dartmouth College has appeared in or been referenced by a number of popular media. Some of the most prominent include:",
"title": "In popular culture"
}
] | Dartmouth College is a private Ivy League research university in Hanover, New Hampshire. Established in 1769 by Eleazar Wheelock, Dartmouth is one of the nine colonial colleges chartered before the American Revolution. It is among the most prestigious universities in the country. Although originally established to educate Native Americans in Christian theology and the English way of life, the university primarily trained Congregationalist ministers during its early history before it gradually secularized. Emerging into national prominence at the turn of the 20th century, Dartmouth was considered to be the most prestigious undergraduate college in the United States in the early 1900s. While Dartmouth is now a research university rather than simply an undergraduate college, it continues to go by "Dartmouth College" to emphasize its focus on undergraduate education. Following a liberal arts curriculum, Dartmouth provides undergraduate instruction in 40 academic departments and interdisciplinary programs, including 60 majors in the humanities, social sciences, natural sciences, and engineering, and enables students to design specialized concentrations or engage in dual degree programs. In addition to the undergraduate faculty of arts and sciences, Dartmouth has four professional and graduate schools: the Geisel School of Medicine, the Thayer School of Engineering, the Tuck School of Business, and the Guarini School of Graduate and Advanced Studies. The university also has affiliations with the Dartmouth–Hitchcock Medical Center. Dartmouth is home to the Rockefeller Center for Public Policy and the Social Sciences, the Hood Museum of Art, the John Sloan Dickey Center for International Understanding, and the Hopkins Center for the Arts. With a student enrollment of about 6,700, Dartmouth is the smallest university in the Ivy League. Undergraduate admissions are highly selective with an acceptance rate of 6% for the class of 2027, including a 4.5% rate for regular decision applicants. Situated on a terrace above the Connecticut River, Dartmouth's 269-acre (109 ha) main campus is in the rural Upper Valley region of New England. The university functions on a quarter system, operating year-round on four ten-week academic terms. Dartmouth is known for its undergraduate focus, Greek culture, and campus traditions. Its 34 varsity sports teams compete intercollegiately in the Ivy League conference of the NCAA Division I. The university has many prominent alumni, including 170 members of the United States Congress, 24 U.S. governors, 8 U.S. Cabinet secretaries, 3 Nobel Prize laureates, 2 U.S. Supreme Court justices, and a U.S. vice president. Other notable alumni include 81 Rhodes Scholars, 26 Marshall Scholarship recipients, 13 Pulitzer Prize recipients, 10 CEOs of Fortune 500 companies, and 51 Olympic medalists. | 2001-09-24T21:48:19Z | 2023-12-31T17:58:37Z | [
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] | https://en.wikipedia.org/wiki/Dartmouth_College |
8,419 | Dartmouth, Devon | Dartmouth (/ˈdɑːrtməθ/) is a town and civil parish in the English county of Devon. It is a tourist destination set on the western bank of the estuary of the River Dart, which is a long narrow tidal ria that runs inland as far as Totnes. It lies within the South Devon Area of Outstanding Natural Beauty and South Hams district, and had a population of 5,512 in 2001, reducing to 5,064 at the 2011 census. There are two electoral wards in the Dartmouth area (Townstal & Kingswear). Their combined population at the above census was 6,822.
In 1086, the Domesday Book listed Dunestal as the only settlement in the area which now makes up the parish of Dartmouth. It was held by Walter of Douai. It paid tax on half a hide, and had two plough teams, two slaves, five villagers and four smallholders. There were six cattle, 40 sheep and 15 goats. At this time Townstal (as the name became) was apparently a purely agricultural settlement, centred around the church. Walter of Douai rebelled against William II, and his lands were confiscated and added to the Honour of Marshwood (Dorset), which sublet Townstal and Dartmouth to the FitzStephens. It was probably during the early part of their proprietorship that Dartmouth began to grow as a port, as it was of strategic importance as a deep-water port for sailing vessels. The port was used as the sailing point for the Crusades of 1147 and 1190, and Warfleet Creek, close to Dartmouth Castle is supposed by some to be named for the vast fleets which assembled there. Dartmouth was a home of the Royal Navy from the reign of Edward III and was twice surprised and sacked during the Hundred Years' War, after which the mouth of the estuary was closed every night with a great chain. The narrow mouth of the Dart is protected by two fortified castles, Dartmouth Castle and Kingswear Castle. Originally Dartmouth's only wharf was Bayard's Cove, a relatively small area protected by a fort at the southern end of the town.
In 1373 Geoffrey Chaucer visited and among the pilgrims in his Canterbury Tales,
A schipman was ther, wonyng fer by weste; For ought I wost, he was of Dertemouthe.
Notwithstanding Dartmouth's connections with the crown and respectable society, it was a major base for privateering in medieval times. John Hawley or Hauley, a licensed privateer and sometime mayor of Dartmouth is reputed to be a model for Chaucer's "schipman".
The earliest street in Dartmouth to be recorded by name (in the 13th century) is Smith Street. Several of the houses on the street are originally late 16th century or early 17th century and probably rebuilt on the site of earlier medieval dwellings. The street name undoubtedly derives from the smiths and shipwrights who built and repaired ships here when the tidal waters reached as far as this point. Smith Street was also the site of the town pillory in medieval times.
The first church in the parish was St Clement's, Townstal, which may have existed in some form before the 1190s. It was granted by the FitzStephens to Torre Abbey in about 1198, the Abbey having been founded in 1196, and the present stone-built church was probably started shortly after this.
Manorial transactions are first recorded in 1220, when the manor house was at Norton, about half a mile west of Townstal. Names of occupations also started to appear, including taverner, tailor, coggar, korker, goldsmith, glover, skinner and baker. The "Fosse", now Foss Street, a dam across the creek known later as The Mill Pool, was first mentioned in 1243. The flow of water out of the pool through the Mill Gullet powered a tidal mill. The dam was used as an unofficial footpath linking Clifton, to the south, with Hardness, to the north. Before this it was necessary to go westwards to the head of the creek at Ford to travel between the two settlements. The lord of the manor was given the rights to hold a weekly market and an annual fair in 1231. In 1281, a legal case proved that the Lord of Totnes had the right to charge tolls on ships using the river, and this right was bought by Nicholas of Tewkesbury in 1306, who conveyed the town, river and port to the king in 1327, so making Dartmouth a Royal Borough. The king gave the river to the Duchy of Cornwall in 1333, who still own the "fundus" or bed of the river. In 1335 Edward III granted Dartmouth to Joan of Carew, whose husband was Lord of Stoke Fleming, and almost immediately she obediently passed the lordship to Guy de Bryan, one of the king's leading ministers. In 1341, the town was granted a Royal Charter, which allowed for the election of a mayor. The borough was required to provide two ships for forty days per year. After 1390, no more is heard of lordship rights, and the borough became effectively independent of any lord.
St Saviour's Church was constructed in 1335 and consecrated in 1372. It contains a pre-Reformation oak rood screen built in 1480 and several monuments including the tomb of John Hawley (died 1408) and his two wives, covered with a large brass plate effigy of all three. A large medieval ironwork door is decorated with two leopards of the Plantagenets and is possibly the original portal. Although it is dated "1631", this is thought to be the date of a subsequent refurbishment coincidental with major renovations of the church in the 17th century. The gallery of the church is decorated with the heraldic crests of prominent local families and is reputed to be constructed of timbers from ships captured during the defeat of the Spanish Armada, although this has not been categorically substantiated. An engraving of a painting by Thomas Allom of the interior of the church, showing the rood screen, provided the inspiration for Letitia Elizabeth Landon's poetical illustration Dartmouth Church in Fisher's Drawing Room scrap Book, 1833.
In medieval times, land access from the Totnes direction passed the manor at Norton and the parish church at Townstal before falling steeply along what are now Church Road, Mount Boone and Ridge Hill to the river at Hardness. There were steeper routes via Townstal Hill and Clarence Street and also via Brown's Hill. These were all too steep for vehicles, so the only land access was by packhorse. In 1671 there is the first mention of the building of the "New Ground". A previously existing sandbank was built up using ships' ballast, and a quay wall was built around it to provide more mooring space. The area proved too unstable to be built on, and is now the Royal Avenue Gardens. It was originally linked to the corner of the Quay by a bridge, opposite Duke Street. At the other end of The Quay, Spithead extended into the river for a few yards.
Dartmouth sent numerous ships to join the English fleet that attacked the Spanish Armada, including the Roebuck, Crescent and Hart. The Nuestra Señora del Rosario, the Spanish Armada's "payship" commanded by Admiral Pedro de Valdés, was captured along with all its crew by Sir Francis Drake. It was reportedly anchored in the River Dart for more than a year and the crew were used as labourers on the nearby Greenway Estate which was the home of Sir Humphrey Gilbert and his half-brother Sir Walter Raleigh. Greenway was later the home of Dame Agatha Christie.
In 1592 the Madre de Deus, a Portuguese treasure ship captured by the English in the Azores, docked at Dartmouth Harbour. It attracted all manner of traders, dealers, cutpurses and thieves and by the time Sir Walter Raleigh arrived to reclaim the Crown's share of the loot, a cargo estimated at half a million pounds had been reduced to £140,000. Still, ten freighters were needed to carry the treasure to London.
Henry Hudson put into Dartmouth on his return from North America, and was arrested for sailing under a foreign flag. The Pilgrim Fathers put into Dartmouth's Bayard's Cove, en route from Southampton to America. They rested a while before setting off on their journey in the Mayflower and the Speedwell on 20 August 1620. About 300 miles west of Land's End, upon realising that the Speedwell was unseaworthy, it returned to Plymouth. The Mayflower departed alone to complete the crossing to Cape Cod. Dartmouth's sister city is Dartmouth, Massachusetts.
The town contains many medieval and Elizabethan streetscapes and is a patchwork of narrow lanes and stone stairways. A significant number of the historic buildings are listed. One of the most obvious is the Butterwalk, built 1635 to 1640. Its intricately carved wooden fascia is supported on granite columns. Charles II held court in the Butterwalk whilst sheltering from storms in 1671 in a room which now forms part of Dartmouth Museum. Much of the interior survives from that time.
The Royal Castle Hotel was built in 1639 on the then new quay. The building was re-fronted in the 19th century, and as the new frontage is itself listed, it is not possible to see the original which lies beneath. A claimant for the oldest building is a former merchant's house in Higher Street, now a Good Beer Guide listed public house called the Cherub, built circa 1380. Agincourt House (next to the Lower Ferry) is also 14th century.
The remains of a fort at Gallants Bower just outside the town are some of the best preserved remains of a Civil War defensive structure. The fort was built by Royalist occupation forces in c. 1643 to the south east of the town, with a similar fort at Mount Ridley on the opposite slopes of what is now Kingswear. The Parliamentarian General Fairfax attacked from the north in 1646, taking the town and forcing the Royalists to surrender, after which Gallants Bower was demolished.
Before 1671, what is now the town centre was almost entirely tidal mud flats. The New Road (now Victoria Road) was constructed across the bed of the (silted up) Mill Pool and up the Ford valley after 1823. Spithead was extended in 1864 when the Dartmouth and Torbay Railway arrived in Kingswear and a pontoon was constructed, linked to Spithead by a bridge. The railway directors and others formed the Dartmouth Harbour Commissioners. At this time, all the roads in those parts of Dartmouth which were not land reclamations were very narrow. In 1864-7 Higher Street was widened into Southtown and linked to Lower Street, which was also widened, with the northern part renamed Fairfax Place. Some of the buildings were rebuilt further back with decorative frontages. In 1881 the Harbour Commissioners produced a scheme for an embankment or esplanade from near the Lower Ferry to Hardness, across the remains of The Pool, to provide an attraction for tourists and further mooring space. It was completed in 1885 after much disagreement between the Borough, the Commissioners and the Railway (now the Great Western Railway). A new station was also built at this time. The building of the Embankment left a section of river isolated between Spithead and the New Ground, which is known as The Boatfloat, and is linked to the river by a bridge for small vessels under the road.
The coming of steam ships led to Dartmouth being used as a bunkering port, with coal being brought in by ship or train. Coal lumpers were members of gangs, who competed to bunker the ships by racing to be first to a ship. This led to the men living as close as possible to the river, and their tenements became grossly overcrowded, with the families living in slum conditions, with up to 15 families in one house, one family to a room.
The Royal National Lifeboat Institution opened the Dart Lifeboat Station at the Sand Quay in 1878, but it was closed in 1896. In all this time only one effective rescue was made by the lifeboat.
The area to the north of Ridge Hill was a shallow and muddy bay ("Coombe Mud") with a narrow road running along the shore linking with the Higher Ferry. The mud was a dumping ground for vessels, including a submarine. The reclamation was completed in 1937 by the extension of the Embankment and the reclamation of the mud behind it, which became Coronation Park.
In the 1920s, aided by government grants, the council made a start on clearing the slums. This was aided by the decline in the use of coal as a fuel for ships. The slums were demolished, and the inhabitants were rehoused in new houses in the Britannia Avenue area, to the west of the old village or hamlet of Townstal. The process was interrupted by the second world war, but was resumed with the construction of many prefabs, and later more houses. Community facilities were minimal at first, but a central area was reserved for a church, which was used by the Baptists and opened in 1954, together with a speedway track. The latter was later used for housing, but a new community centre was opened nearby, together with a leisure centre, an outdoor swimming pool, and later an indoor pool, and supermarkets. There are also light industrial units.
In the latter part of the Second World War the town was a base for American forces and one of the departure points for Utah Beach in the D Day landings. Slipways and harbour improvements were also constructed. Much of the surrounding countryside and notably Slapton Sands was closed to the public while it was used by US troops for practise landings and manoeuvres. Between 1985 and 1990 the Embankment was widened by 6 metres and raised to prevent flooding at spring tides. A tidal lock gate was provided at the Boatfloat bridge, which could be closed at such times.
Dart Lifeboat Station was reopened in 2007, the first time that a lifeboat had been stationed in the town since 1896. It has initially been kept in a temporary building in Coronation Park.
In 2010, a fire seriously damaged numerous historical properties in Fairfax Place and Higher Street. Several were Tudor and Grade I or Grade II listed buildings.
The town was an ancient borough, incorporated by Edward III, known formally as Clifton-Dartmouth-Hardness, and consisting of the three parishes of St Petrox, St Saviour and Townstal, and incorporating the hamlets of Ford, Old Mill and Norton. It was reformed under the Municipal Corporations Act 1835. The town returned two members of parliament from the 13th century until 1835, after which one Member of Parliament (MP) was elected until the town was disenfranchised in 1868. It remained a municipal borough until 1974, when it was merged into the South Hams district, and became a successor parish of Dartmouth with a town council.
Dartmouth Town Council is the lowest of three tiers of local government. It consists of 16 councillors representing the two wards of Clifton and Townstal. At the second tier, Dartmouth forms part of the Dartmouth and Kingswear ward of South Hams District Council, which returns three councillors. At the upper tier of local government Dartmouth and Kingswear Electoral Division elects one member to Devon County Council.
The Port of Dartmouth Royal Regatta takes place annually over three days at the end of August. The event sees the traditional regatta boat races along with markets, fun fairs, community games, musical performances, air displays including the Red Arrows and fireworks. A Royal Navy guard ship is often present at the event. Other cultural events include beer festivals in February and July (the latter in Kingswear), a music festival and an art and craft weekend in June, a food festival in October and a Christmas candlelit event.
The Flavel Centre incorporates the public library and performance spaces, featuring films, live music and comedy and exhibitions.
Bayard's Cove has been used in several television productions, including The Onedin Line a popular BBC television drama series that ran from 1971 to 1980. Many of the scenes from the BBC's popular series Down to Earth, starring Ricky Tomlinson, were filmed at various locations around the town.
Notable tourist attractions include the Dartmouth Royal Naval College, Bayard's Cove Fort, Dartmouth Castle and the Dartmouth Steam Railway which terminates at Kingswear on the opposite bank of the river.
Boat cruises to nearby places along the coast (such as Torbay and Start Bay) and up the river (to Totnes, Dittisham and the Greenway Estate) are provided by several companies. The paddlesteamer PS Kingswear Castle returned to the town in 2013. The South West Coast Path National Trail passes through the town, and also through extensive National Trust coastal properties at Little Dartmouth and Brownstone (Kingswear). The Dart Valley Trail starts in Dartmouth, with routes either side of the River Dart as far as Dittisham, and continuing to Totnes via Cornworthy, Tuckenhay and Ashprington. The area has long been well regarded for yachting, and there are extensive marinas at Sandquay, Kingswear and Noss (approximately one mile north of Kingswear).
The nearest Met Office weather station is Slapton, about 5 miles south-south west of Dartmouth and a similar distance from the coast. As with the rest of the British Isles and South West England, the area experiences a maritime climate with warm summers and mild winters—this is particularly pronounced due to its position near the coast—extremes range from a record low of just −8.0 °C (17.6 °F) in January 1987 up to a record high of 30.5 °C (86.9 °F) during June 1976.
Dartmouth is linked to Kingswear, on the other side of the River Dart, by three ferries. The Higher Ferry and the Lower Ferry are both vehicular ferries. The Passenger Ferry, as its name suggests, carries only passengers, principally to connect with the Dartmouth Steam Railway at Kingswear railway station. The nearest bridge across the Dart is in Totnes, some 11 miles (18 km) away by road.
The A379 road runs through Dartmouth, linking the town to Slapton and Kingsbridge to the southwest and to Torbay to the east across the Higher Ferry. The A3122 connects Dartmouth to a junction with the A381, and hence to both Totnes and a more direct route to Kingsbridge. Stagecoach South West provides local town bus services and links to Plymouth, Totnes and Exeter, and Kingsbridge. In addition it provides links to the Torbay resorts of Brixham, Paignton and Torquay from Kingswear via the ferry.
No railway has ever run to Dartmouth, but the town does have a railway station, opened on 31 March 1890 to replace the original facility on the pontoon, although it is now a restaurant. In fact Dartmouth Railway Station was built while the line from Paignton to the River Dart was still being built, anticipating a bridge across the river being built near the present Greenway Halt. The railway line to Kingswear was opened in 1864. As a result of shortage of capital, a deviation from the original scheme to run the line from Churston to Greenway with a steamer service to Dartmouth was proposed, but defeated in Parliament. It had been suggested that this could, at a later date, be used as a jumping off point for a bridge to the west bank of the Dart and a line direct to Dartmouth. In 1900, a Light Railway scheme was proposed for a crossing of the Dart near Maypool to join another line from Totnes and then proceed to Kingsbridge and Yealmpton, with a branch to Salcombe. This was also defeated by lack of funds. The railway terminated at a station called "Kingswear for Dartmouth" (now on the Dartmouth Steam Railway) and a ferry took passengers across the river to the station at Dartmouth railway station, which had a dedicated pontoon. British Railways formally closed the line to mainline passenger trains in 1973, but it immediately re-opened as a heritage line and has run as one ever since.
The town is home to the Royal Navy's officer training college (Britannia Royal Naval College), where all officers of the Royal Navy and many foreign naval officers are trained.
Dartmouth has one primary school—St John the Baptist R.C. Primary School, and one all-through school—Dartmouth Academy—for those aged 3–16. Dartmouth also has a pre-school in the centre of town, established for over 40 years and based in the old Victorian school rooms at South Ford Road. It provides care for 2- to 5-year-olds and is run as a charitable organisation.
Dartmouth has a Non-League football club Dartmouth A.F.C. who play at Long Cross.
Dartmouth also hosts the annual "World Indoor Rally Championship", based on slot car racing in the late summer.
At the end of August and early September there is the annual Port of Dartmouth Royal Regatta.
Since 1905 Dartmouth has had a greenhouse as part of the Royal Avenue Gardens. In May 2013 this building, used for the previous 10 years by Dartmouth in Bloom, a not-for-profit organisation affiliated with Britain in Bloom, was closed as structurally unsound. There are proposals to restore the greenhouse to its prior Edwardian style. | [
{
"paragraph_id": 0,
"text": "Dartmouth (/ˈdɑːrtməθ/) is a town and civil parish in the English county of Devon. It is a tourist destination set on the western bank of the estuary of the River Dart, which is a long narrow tidal ria that runs inland as far as Totnes. It lies within the South Devon Area of Outstanding Natural Beauty and South Hams district, and had a population of 5,512 in 2001, reducing to 5,064 at the 2011 census. There are two electoral wards in the Dartmouth area (Townstal & Kingswear). Their combined population at the above census was 6,822.",
"title": ""
},
{
"paragraph_id": 1,
"text": "In 1086, the Domesday Book listed Dunestal as the only settlement in the area which now makes up the parish of Dartmouth. It was held by Walter of Douai. It paid tax on half a hide, and had two plough teams, two slaves, five villagers and four smallholders. There were six cattle, 40 sheep and 15 goats. At this time Townstal (as the name became) was apparently a purely agricultural settlement, centred around the church. Walter of Douai rebelled against William II, and his lands were confiscated and added to the Honour of Marshwood (Dorset), which sublet Townstal and Dartmouth to the FitzStephens. It was probably during the early part of their proprietorship that Dartmouth began to grow as a port, as it was of strategic importance as a deep-water port for sailing vessels. The port was used as the sailing point for the Crusades of 1147 and 1190, and Warfleet Creek, close to Dartmouth Castle is supposed by some to be named for the vast fleets which assembled there. Dartmouth was a home of the Royal Navy from the reign of Edward III and was twice surprised and sacked during the Hundred Years' War, after which the mouth of the estuary was closed every night with a great chain. The narrow mouth of the Dart is protected by two fortified castles, Dartmouth Castle and Kingswear Castle. Originally Dartmouth's only wharf was Bayard's Cove, a relatively small area protected by a fort at the southern end of the town.",
"title": "History"
},
{
"paragraph_id": 2,
"text": "In 1373 Geoffrey Chaucer visited and among the pilgrims in his Canterbury Tales,",
"title": "History"
},
{
"paragraph_id": 3,
"text": "A schipman was ther, wonyng fer by weste; For ought I wost, he was of Dertemouthe.",
"title": "History"
},
{
"paragraph_id": 4,
"text": "Notwithstanding Dartmouth's connections with the crown and respectable society, it was a major base for privateering in medieval times. John Hawley or Hauley, a licensed privateer and sometime mayor of Dartmouth is reputed to be a model for Chaucer's \"schipman\".",
"title": "History"
},
{
"paragraph_id": 5,
"text": "The earliest street in Dartmouth to be recorded by name (in the 13th century) is Smith Street. Several of the houses on the street are originally late 16th century or early 17th century and probably rebuilt on the site of earlier medieval dwellings. The street name undoubtedly derives from the smiths and shipwrights who built and repaired ships here when the tidal waters reached as far as this point. Smith Street was also the site of the town pillory in medieval times.",
"title": "History"
},
{
"paragraph_id": 6,
"text": "The first church in the parish was St Clement's, Townstal, which may have existed in some form before the 1190s. It was granted by the FitzStephens to Torre Abbey in about 1198, the Abbey having been founded in 1196, and the present stone-built church was probably started shortly after this.",
"title": "History"
},
{
"paragraph_id": 7,
"text": "Manorial transactions are first recorded in 1220, when the manor house was at Norton, about half a mile west of Townstal. Names of occupations also started to appear, including taverner, tailor, coggar, korker, goldsmith, glover, skinner and baker. The \"Fosse\", now Foss Street, a dam across the creek known later as The Mill Pool, was first mentioned in 1243. The flow of water out of the pool through the Mill Gullet powered a tidal mill. The dam was used as an unofficial footpath linking Clifton, to the south, with Hardness, to the north. Before this it was necessary to go westwards to the head of the creek at Ford to travel between the two settlements. The lord of the manor was given the rights to hold a weekly market and an annual fair in 1231. In 1281, a legal case proved that the Lord of Totnes had the right to charge tolls on ships using the river, and this right was bought by Nicholas of Tewkesbury in 1306, who conveyed the town, river and port to the king in 1327, so making Dartmouth a Royal Borough. The king gave the river to the Duchy of Cornwall in 1333, who still own the \"fundus\" or bed of the river. In 1335 Edward III granted Dartmouth to Joan of Carew, whose husband was Lord of Stoke Fleming, and almost immediately she obediently passed the lordship to Guy de Bryan, one of the king's leading ministers. In 1341, the town was granted a Royal Charter, which allowed for the election of a mayor. The borough was required to provide two ships for forty days per year. After 1390, no more is heard of lordship rights, and the borough became effectively independent of any lord.",
"title": "History"
},
{
"paragraph_id": 8,
"text": "St Saviour's Church was constructed in 1335 and consecrated in 1372. It contains a pre-Reformation oak rood screen built in 1480 and several monuments including the tomb of John Hawley (died 1408) and his two wives, covered with a large brass plate effigy of all three. A large medieval ironwork door is decorated with two leopards of the Plantagenets and is possibly the original portal. Although it is dated \"1631\", this is thought to be the date of a subsequent refurbishment coincidental with major renovations of the church in the 17th century. The gallery of the church is decorated with the heraldic crests of prominent local families and is reputed to be constructed of timbers from ships captured during the defeat of the Spanish Armada, although this has not been categorically substantiated. An engraving of a painting by Thomas Allom of the interior of the church, showing the rood screen, provided the inspiration for Letitia Elizabeth Landon's poetical illustration Dartmouth Church in Fisher's Drawing Room scrap Book, 1833.",
"title": "History"
},
{
"paragraph_id": 9,
"text": "In medieval times, land access from the Totnes direction passed the manor at Norton and the parish church at Townstal before falling steeply along what are now Church Road, Mount Boone and Ridge Hill to the river at Hardness. There were steeper routes via Townstal Hill and Clarence Street and also via Brown's Hill. These were all too steep for vehicles, so the only land access was by packhorse. In 1671 there is the first mention of the building of the \"New Ground\". A previously existing sandbank was built up using ships' ballast, and a quay wall was built around it to provide more mooring space. The area proved too unstable to be built on, and is now the Royal Avenue Gardens. It was originally linked to the corner of the Quay by a bridge, opposite Duke Street. At the other end of The Quay, Spithead extended into the river for a few yards.",
"title": "History"
},
{
"paragraph_id": 10,
"text": "Dartmouth sent numerous ships to join the English fleet that attacked the Spanish Armada, including the Roebuck, Crescent and Hart. The Nuestra Señora del Rosario, the Spanish Armada's \"payship\" commanded by Admiral Pedro de Valdés, was captured along with all its crew by Sir Francis Drake. It was reportedly anchored in the River Dart for more than a year and the crew were used as labourers on the nearby Greenway Estate which was the home of Sir Humphrey Gilbert and his half-brother Sir Walter Raleigh. Greenway was later the home of Dame Agatha Christie.",
"title": "History"
},
{
"paragraph_id": 11,
"text": "In 1592 the Madre de Deus, a Portuguese treasure ship captured by the English in the Azores, docked at Dartmouth Harbour. It attracted all manner of traders, dealers, cutpurses and thieves and by the time Sir Walter Raleigh arrived to reclaim the Crown's share of the loot, a cargo estimated at half a million pounds had been reduced to £140,000. Still, ten freighters were needed to carry the treasure to London.",
"title": "History"
},
{
"paragraph_id": 12,
"text": "Henry Hudson put into Dartmouth on his return from North America, and was arrested for sailing under a foreign flag. The Pilgrim Fathers put into Dartmouth's Bayard's Cove, en route from Southampton to America. They rested a while before setting off on their journey in the Mayflower and the Speedwell on 20 August 1620. About 300 miles west of Land's End, upon realising that the Speedwell was unseaworthy, it returned to Plymouth. The Mayflower departed alone to complete the crossing to Cape Cod. Dartmouth's sister city is Dartmouth, Massachusetts.",
"title": "History"
},
{
"paragraph_id": 13,
"text": "The town contains many medieval and Elizabethan streetscapes and is a patchwork of narrow lanes and stone stairways. A significant number of the historic buildings are listed. One of the most obvious is the Butterwalk, built 1635 to 1640. Its intricately carved wooden fascia is supported on granite columns. Charles II held court in the Butterwalk whilst sheltering from storms in 1671 in a room which now forms part of Dartmouth Museum. Much of the interior survives from that time.",
"title": "History"
},
{
"paragraph_id": 14,
"text": "The Royal Castle Hotel was built in 1639 on the then new quay. The building was re-fronted in the 19th century, and as the new frontage is itself listed, it is not possible to see the original which lies beneath. A claimant for the oldest building is a former merchant's house in Higher Street, now a Good Beer Guide listed public house called the Cherub, built circa 1380. Agincourt House (next to the Lower Ferry) is also 14th century.",
"title": "History"
},
{
"paragraph_id": 15,
"text": "The remains of a fort at Gallants Bower just outside the town are some of the best preserved remains of a Civil War defensive structure. The fort was built by Royalist occupation forces in c. 1643 to the south east of the town, with a similar fort at Mount Ridley on the opposite slopes of what is now Kingswear. The Parliamentarian General Fairfax attacked from the north in 1646, taking the town and forcing the Royalists to surrender, after which Gallants Bower was demolished.",
"title": "History"
},
{
"paragraph_id": 16,
"text": "Before 1671, what is now the town centre was almost entirely tidal mud flats. The New Road (now Victoria Road) was constructed across the bed of the (silted up) Mill Pool and up the Ford valley after 1823. Spithead was extended in 1864 when the Dartmouth and Torbay Railway arrived in Kingswear and a pontoon was constructed, linked to Spithead by a bridge. The railway directors and others formed the Dartmouth Harbour Commissioners. At this time, all the roads in those parts of Dartmouth which were not land reclamations were very narrow. In 1864-7 Higher Street was widened into Southtown and linked to Lower Street, which was also widened, with the northern part renamed Fairfax Place. Some of the buildings were rebuilt further back with decorative frontages. In 1881 the Harbour Commissioners produced a scheme for an embankment or esplanade from near the Lower Ferry to Hardness, across the remains of The Pool, to provide an attraction for tourists and further mooring space. It was completed in 1885 after much disagreement between the Borough, the Commissioners and the Railway (now the Great Western Railway). A new station was also built at this time. The building of the Embankment left a section of river isolated between Spithead and the New Ground, which is known as The Boatfloat, and is linked to the river by a bridge for small vessels under the road.",
"title": "History"
},
{
"paragraph_id": 17,
"text": "The coming of steam ships led to Dartmouth being used as a bunkering port, with coal being brought in by ship or train. Coal lumpers were members of gangs, who competed to bunker the ships by racing to be first to a ship. This led to the men living as close as possible to the river, and their tenements became grossly overcrowded, with the families living in slum conditions, with up to 15 families in one house, one family to a room.",
"title": "History"
},
{
"paragraph_id": 18,
"text": "The Royal National Lifeboat Institution opened the Dart Lifeboat Station at the Sand Quay in 1878, but it was closed in 1896. In all this time only one effective rescue was made by the lifeboat.",
"title": "History"
},
{
"paragraph_id": 19,
"text": "The area to the north of Ridge Hill was a shallow and muddy bay (\"Coombe Mud\") with a narrow road running along the shore linking with the Higher Ferry. The mud was a dumping ground for vessels, including a submarine. The reclamation was completed in 1937 by the extension of the Embankment and the reclamation of the mud behind it, which became Coronation Park.",
"title": "History"
},
{
"paragraph_id": 20,
"text": "In the 1920s, aided by government grants, the council made a start on clearing the slums. This was aided by the decline in the use of coal as a fuel for ships. The slums were demolished, and the inhabitants were rehoused in new houses in the Britannia Avenue area, to the west of the old village or hamlet of Townstal. The process was interrupted by the second world war, but was resumed with the construction of many prefabs, and later more houses. Community facilities were minimal at first, but a central area was reserved for a church, which was used by the Baptists and opened in 1954, together with a speedway track. The latter was later used for housing, but a new community centre was opened nearby, together with a leisure centre, an outdoor swimming pool, and later an indoor pool, and supermarkets. There are also light industrial units.",
"title": "History"
},
{
"paragraph_id": 21,
"text": "In the latter part of the Second World War the town was a base for American forces and one of the departure points for Utah Beach in the D Day landings. Slipways and harbour improvements were also constructed. Much of the surrounding countryside and notably Slapton Sands was closed to the public while it was used by US troops for practise landings and manoeuvres. Between 1985 and 1990 the Embankment was widened by 6 metres and raised to prevent flooding at spring tides. A tidal lock gate was provided at the Boatfloat bridge, which could be closed at such times.",
"title": "History"
},
{
"paragraph_id": 22,
"text": "Dart Lifeboat Station was reopened in 2007, the first time that a lifeboat had been stationed in the town since 1896. It has initially been kept in a temporary building in Coronation Park.",
"title": "History"
},
{
"paragraph_id": 23,
"text": "In 2010, a fire seriously damaged numerous historical properties in Fairfax Place and Higher Street. Several were Tudor and Grade I or Grade II listed buildings.",
"title": "History"
},
{
"paragraph_id": 24,
"text": "The town was an ancient borough, incorporated by Edward III, known formally as Clifton-Dartmouth-Hardness, and consisting of the three parishes of St Petrox, St Saviour and Townstal, and incorporating the hamlets of Ford, Old Mill and Norton. It was reformed under the Municipal Corporations Act 1835. The town returned two members of parliament from the 13th century until 1835, after which one Member of Parliament (MP) was elected until the town was disenfranchised in 1868. It remained a municipal borough until 1974, when it was merged into the South Hams district, and became a successor parish of Dartmouth with a town council.",
"title": "Governance"
},
{
"paragraph_id": 25,
"text": "Dartmouth Town Council is the lowest of three tiers of local government. It consists of 16 councillors representing the two wards of Clifton and Townstal. At the second tier, Dartmouth forms part of the Dartmouth and Kingswear ward of South Hams District Council, which returns three councillors. At the upper tier of local government Dartmouth and Kingswear Electoral Division elects one member to Devon County Council.",
"title": "Governance"
},
{
"paragraph_id": 26,
"text": "The Port of Dartmouth Royal Regatta takes place annually over three days at the end of August. The event sees the traditional regatta boat races along with markets, fun fairs, community games, musical performances, air displays including the Red Arrows and fireworks. A Royal Navy guard ship is often present at the event. Other cultural events include beer festivals in February and July (the latter in Kingswear), a music festival and an art and craft weekend in June, a food festival in October and a Christmas candlelit event.",
"title": "Culture and tourism"
},
{
"paragraph_id": 27,
"text": "The Flavel Centre incorporates the public library and performance spaces, featuring films, live music and comedy and exhibitions.",
"title": "Culture and tourism"
},
{
"paragraph_id": 28,
"text": "Bayard's Cove has been used in several television productions, including The Onedin Line a popular BBC television drama series that ran from 1971 to 1980. Many of the scenes from the BBC's popular series Down to Earth, starring Ricky Tomlinson, were filmed at various locations around the town.",
"title": "Culture and tourism"
},
{
"paragraph_id": 29,
"text": "Notable tourist attractions include the Dartmouth Royal Naval College, Bayard's Cove Fort, Dartmouth Castle and the Dartmouth Steam Railway which terminates at Kingswear on the opposite bank of the river.",
"title": "Culture and tourism"
},
{
"paragraph_id": 30,
"text": "Boat cruises to nearby places along the coast (such as Torbay and Start Bay) and up the river (to Totnes, Dittisham and the Greenway Estate) are provided by several companies. The paddlesteamer PS Kingswear Castle returned to the town in 2013. The South West Coast Path National Trail passes through the town, and also through extensive National Trust coastal properties at Little Dartmouth and Brownstone (Kingswear). The Dart Valley Trail starts in Dartmouth, with routes either side of the River Dart as far as Dittisham, and continuing to Totnes via Cornworthy, Tuckenhay and Ashprington. The area has long been well regarded for yachting, and there are extensive marinas at Sandquay, Kingswear and Noss (approximately one mile north of Kingswear).",
"title": "Culture and tourism"
},
{
"paragraph_id": 31,
"text": "The nearest Met Office weather station is Slapton, about 5 miles south-south west of Dartmouth and a similar distance from the coast. As with the rest of the British Isles and South West England, the area experiences a maritime climate with warm summers and mild winters—this is particularly pronounced due to its position near the coast—extremes range from a record low of just −8.0 °C (17.6 °F) in January 1987 up to a record high of 30.5 °C (86.9 °F) during June 1976.",
"title": "Climate"
},
{
"paragraph_id": 32,
"text": "Dartmouth is linked to Kingswear, on the other side of the River Dart, by three ferries. The Higher Ferry and the Lower Ferry are both vehicular ferries. The Passenger Ferry, as its name suggests, carries only passengers, principally to connect with the Dartmouth Steam Railway at Kingswear railway station. The nearest bridge across the Dart is in Totnes, some 11 miles (18 km) away by road.",
"title": "Transport"
},
{
"paragraph_id": 33,
"text": "The A379 road runs through Dartmouth, linking the town to Slapton and Kingsbridge to the southwest and to Torbay to the east across the Higher Ferry. The A3122 connects Dartmouth to a junction with the A381, and hence to both Totnes and a more direct route to Kingsbridge. Stagecoach South West provides local town bus services and links to Plymouth, Totnes and Exeter, and Kingsbridge. In addition it provides links to the Torbay resorts of Brixham, Paignton and Torquay from Kingswear via the ferry.",
"title": "Transport"
},
{
"paragraph_id": 34,
"text": "No railway has ever run to Dartmouth, but the town does have a railway station, opened on 31 March 1890 to replace the original facility on the pontoon, although it is now a restaurant. In fact Dartmouth Railway Station was built while the line from Paignton to the River Dart was still being built, anticipating a bridge across the river being built near the present Greenway Halt. The railway line to Kingswear was opened in 1864. As a result of shortage of capital, a deviation from the original scheme to run the line from Churston to Greenway with a steamer service to Dartmouth was proposed, but defeated in Parliament. It had been suggested that this could, at a later date, be used as a jumping off point for a bridge to the west bank of the Dart and a line direct to Dartmouth. In 1900, a Light Railway scheme was proposed for a crossing of the Dart near Maypool to join another line from Totnes and then proceed to Kingsbridge and Yealmpton, with a branch to Salcombe. This was also defeated by lack of funds. The railway terminated at a station called \"Kingswear for Dartmouth\" (now on the Dartmouth Steam Railway) and a ferry took passengers across the river to the station at Dartmouth railway station, which had a dedicated pontoon. British Railways formally closed the line to mainline passenger trains in 1973, but it immediately re-opened as a heritage line and has run as one ever since.",
"title": "Transport"
},
{
"paragraph_id": 35,
"text": "The town is home to the Royal Navy's officer training college (Britannia Royal Naval College), where all officers of the Royal Navy and many foreign naval officers are trained.",
"title": "Education"
},
{
"paragraph_id": 36,
"text": "Dartmouth has one primary school—St John the Baptist R.C. Primary School, and one all-through school—Dartmouth Academy—for those aged 3–16. Dartmouth also has a pre-school in the centre of town, established for over 40 years and based in the old Victorian school rooms at South Ford Road. It provides care for 2- to 5-year-olds and is run as a charitable organisation.",
"title": "Education"
},
{
"paragraph_id": 37,
"text": "Dartmouth has a Non-League football club Dartmouth A.F.C. who play at Long Cross.",
"title": "Sport and leisure"
},
{
"paragraph_id": 38,
"text": "Dartmouth also hosts the annual \"World Indoor Rally Championship\", based on slot car racing in the late summer.",
"title": "Sport and leisure"
},
{
"paragraph_id": 39,
"text": "At the end of August and early September there is the annual Port of Dartmouth Royal Regatta.",
"title": "Sport and leisure"
},
{
"paragraph_id": 40,
"text": "Since 1905 Dartmouth has had a greenhouse as part of the Royal Avenue Gardens. In May 2013 this building, used for the previous 10 years by Dartmouth in Bloom, a not-for-profit organisation affiliated with Britain in Bloom, was closed as structurally unsound. There are proposals to restore the greenhouse to its prior Edwardian style.",
"title": "Sport and leisure"
}
] | Dartmouth is a town and civil parish in the English county of Devon. It is a tourist destination set on the western bank of the estuary of the River Dart, which is a long narrow tidal ria that runs inland as far as Totnes. It lies within the South Devon Area of Outstanding Natural Beauty and South Hams district, and had a population of 5,512 in 2001, reducing to 5,064 at the 2011 census. There are two electoral wards in the Dartmouth area. Their combined population at the above census was 6,822. | 2001-09-10T06:04:05Z | 2023-10-06T10:30:07Z | [
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8,420 | Dodo | The dodo (Raphus cucullatus) is an extinct flightless bird that was endemic to the island of Mauritius, which is east of Madagascar in the Indian Ocean. The dodo's closest relative was the also-extinct and flightless Rodrigues solitaire. The two formed the subfamily Raphinae, a clade of extinct flightless birds that were a part of the family which includes pigeons and doves. The closest living relative of the dodo is the Nicobar pigeon. A white dodo was once thought to have existed on the nearby island of Réunion, but it is now believed that this assumption was merely confusion based on the also-extinct Réunion ibis and paintings of white dodos.
Subfossil remains show the dodo measured around 62.6–75 centimetres (2.05–2.46 ft) in height and may have weighed 10.6–17.5 kg (23–39 lb) in the wild. The dodo's appearance in life is evidenced only by drawings, paintings, and written accounts from the 17th century. Since these portraits vary considerably, and since only some of the illustrations are known to have been drawn from live specimens, the dodos' exact appearance in life remains unresolved, and little is known about its behaviour. It has been depicted with brownish-grey plumage, yellow feet, a tuft of tail feathers, a grey, naked head, and a black, yellow, and green beak. It used gizzard stones to help digest its food, which is thought to have included fruits, and its main habitat is believed to have been the woods in the drier coastal areas of Mauritius. One account states its clutch consisted of a single egg. It is presumed that the dodo became flightless because of the ready availability of abundant food sources and a relative absence of predators on Mauritius. Though the dodo has historically been portrayed as being fat and clumsy, it is now thought to have been well-adapted for its ecosystem.
The first recorded mention of the dodo was by Dutch sailors in 1598. In the following years, the bird was hunted by sailors and invasive species, while its habitat was being destroyed. The last widely accepted sighting of a dodo was in 1662. Its extinction was not immediately noticed, and some considered the bird to be a myth. In the 19th century, research was conducted on a small quantity of remains of four specimens that had been brought to Europe in the early 17th century. Among these is a dried head, the only soft tissue of the dodo that remains today. Since then, a large amount of subfossil material has been collected on Mauritius, mostly from the Mare aux Songes swamp. The extinction of the dodo within less than a century of its discovery called attention to the previously unrecognised problem of human involvement in the disappearance of entire species. The dodo achieved widespread recognition from its role in the story of Alice's Adventures in Wonderland, and it has since become a fixture in popular culture, often as a symbol of extinction and obsolescence.
The dodo was variously declared a small ostrich, a rail, an albatross, or a vulture, by early scientists. In 1842, Danish zoologist Johannes Theodor Reinhardt proposed that dodos were ground pigeons, based on studies of a dodo skull he had discovered in the collection of the Natural History Museum of Denmark. This view was met with ridicule, but was later supported by English naturalists Hugh Edwin Strickland and Alexander Gordon Melville in their 1848 monograph The Dodo and Its Kindred, which attempted to separate myth from reality. After dissecting the preserved head and foot of the specimen at the Oxford University Museum and comparing it with the few remains then available of the extinct Rodrigues solitaire (Pezophaps solitaria) they concluded that the two were closely related. Strickland stated that although not identical, these birds shared many distinguishing features of the leg bones, otherwise known only in pigeons.
Strickland and Melville established that the dodo was anatomically similar to pigeons in many features. They pointed to the very short keratinous portion of the beak, with its long, slender, naked basal part. Other pigeons also have bare skin around their eyes, almost reaching their beak, as in dodos. The forehead was high in relation to the beak, and the nostril was located low on the middle of the beak and surrounded by skin, a combination of features shared only with pigeons. The legs of the dodo were generally more similar to those of terrestrial pigeons than of other birds, both in their scales and in their skeletal features. Depictions of the large crop hinted at a relationship with pigeons, in which this feature is more developed than in other birds. Pigeons generally have very small clutches, and the dodo is said to have laid a single egg. Like pigeons, the dodo lacked the vomer and septum of the nostrils, and it shared details in the mandible, the zygomatic bone, the palate, and the hallux. The dodo differed from other pigeons mainly in the small size of the wings and the large size of the beak in proportion to the rest of the cranium.
Throughout the 19th century, several species were classified as congeneric with the dodo, including the Rodrigues solitaire and the Réunion solitaire, as Didus solitarius and Raphus solitarius, respectively (Didus and Raphus being names for the dodo genus used by different authors of the time). An atypical 17th-century description of a dodo and bones found on Rodrigues, now known to have belonged to the Rodrigues solitaire, led Abraham Dee Bartlett to name a new species, Didus nazarenus, in 1852. Based on solitaire remains, it is now a synonym of that species. Crude drawings of the red rail of Mauritius were also misinterpreted as dodo species; Didus broeckii and Didus herberti.
For many years the dodo and the Rodrigues solitaire were placed in a family of their own, the Raphidae (formerly Dididae), because their exact relationships with other pigeons were unresolved. Each was also placed in its own monotypic family (Raphidae and Pezophapidae, respectively), as it was thought that they had evolved their similarities independently. Osteological and DNA analysis has since led to the dissolution of the family Raphidae, and the dodo and solitaire are now placed in their own subfamily, Raphinae, within the family Columbidae.
In 2002, American geneticist Beth Shapiro and colleagues analysed the DNA of the dodo for the first time. Comparison of mitochondrial cytochrome b and 12S rRNA sequences isolated from a tarsal of the Oxford specimen and a femur of a Rodrigues solitaire confirmed their close relationship and their placement within the Columbidae. The genetic evidence was interpreted as showing the Southeast Asian Nicobar pigeon (Caloenas nicobarica) to be their closest living relative, followed by the crowned pigeons (Goura) of New Guinea, and the superficially dodo-like tooth-billed pigeon (Didunculus strigirostris) from Samoa (its scientific name refers to its dodo-like beak). This clade consists of generally ground-dwelling island endemic pigeons. The following cladogram shows the dodo's closest relationships within the Columbidae, based on Shapiro and colleagues, 2002:
A similar cladogram was published in 2007, inverting the placement of Goura and Didunculus and including the pheasant pigeon (Otidiphaps nobilis) and the thick-billed ground pigeon (Trugon terrestris) at the base of the clade. The DNA used in these studies was obtained from the Oxford specimen, and since this material is degraded, and no usable DNA has been extracted from subfossil remains, these findings still need to be independently verified. Based on behavioural and morphological evidence, Jolyon C. Parish proposed that the dodo and Rodrigues solitaire should be placed in the subfamily Gourinae along with the Goura pigeons and others, in agreement with the genetic evidence. In 2014, DNA of the only known specimen of the recently extinct spotted green pigeon (Caloenas maculata) was analysed, and it was found to be a close relative of the Nicobar pigeon, and thus also the dodo and Rodrigues solitaire.
The 2002 study indicated that the ancestors of the dodo and the solitaire diverged around the Paleogene-Neogene boundary, about 23.03 million years ago. The Mascarene Islands (Mauritius, Réunion, and Rodrigues), are of volcanic origin and are less than 10 million years old. Therefore, the ancestors of both birds probably remained capable of flight for a considerable time after the separation of their lineage. The Nicobar and spotted green pigeon were placed at the base of a lineage leading to the Raphinae, which indicates the flightless raphines had ancestors that were able to fly, were semi-terrestrial, and inhabited islands. This in turn supports the hypothesis that the ancestors of those birds reached the Mascarene islands by island hopping from South Asia. The lack of mammalian herbivores competing for resources on these islands allowed the solitaire and the dodo to attain very large sizes and flightlessness. Despite its divergent skull morphology and adaptations for larger size, many features of its skeleton remained similar to those of smaller, flying pigeons. Another large, flightless pigeon, the Viti Levu giant pigeon (Natunaornis gigoura), was described in 2001 from subfossil material from Fiji. It was only slightly smaller than the dodo and the solitaire, and it too is thought to have been related to the crowned pigeons.
One of the original names for the dodo was the Dutch "Walghvoghel", first used in the journal of Dutch Vice Admiral Wybrand van Warwijck, who visited Mauritius during the Second Dutch Expedition to Indonesia in 1598. Walghe means "tasteless", "insipid", or "sickly", and voghel means "bird". The name was translated by Jakob Friedlib into German as Walchstök or Walchvögel. The original Dutch report titled Waarachtige Beschryving was lost, but the English translation survived:
On their left hand was a little island which they named Heemskirk Island, and the bay it selve they called Warwick Bay... Here they taried 12. daies to refresh themselues, finding in this place great quantity of foules twice as bigge as swans, which they call Walghstocks or Wallowbirdes being very good meat. But finding an abundance of pigeons & popinnayes [parrots], they disdained any more to eat those great foules calling them Wallowbirds, that is to say lothsome or fulsome birdes.
Another account from that voyage, perhaps the first to mention the dodo, states that the Portuguese referred to them as penguins. The meaning may not have been derived from penguin (the Portuguese referred to those birds as "fotilicaios" at the time), but from pinion, a reference to the small wings. The crew of the Dutch ship Gelderland referred to the bird as "Dronte" (meaning "swollen") in 1602, a name that is still used in some languages. This crew also called them "griff-eendt" and "kermisgans", in reference to fowl fattened for the Kermesse festival in Amsterdam, which was held the day after they anchored on Mauritius.
The etymology of the word dodo is unclear. Some ascribe it to the Dutch word dodoor for "sluggard", but it is more probably related to Dodaars, which means either "fat-arse" or "knot-arse", referring to the knot of feathers on the hind end. The first record of the word Dodaars is in Captain Willem Van West-Zanen's journal in 1602. The English writer Sir Thomas Herbert was the first to use the word dodo in print in his 1634 travelogue claiming it was referred to as such by the Portuguese, who had visited Mauritius in 1507. Another Englishman, Emmanuel Altham, had used the word in a 1628 letter in which he also claimed its origin was Portuguese. The name "dodar" was introduced into English at the same time as dodo, but was only used until the 18th century. As far as is known, the Portuguese never mentioned the bird. Nevertheless, some sources still state that the word dodo derives from the Portuguese word doudo (currently doido), meaning "fool" or "crazy". It has also been suggested that dodo was an onomatopoeic approximation of the bird's call, a two-note pigeon-like sound resembling "doo-doo".
The Latin name cucullatus ("hooded") was first used by Juan Eusebio Nieremberg in 1635 as Cygnus cucullatus, in reference to Carolus Clusius's 1605 depiction of a dodo. In his 18th-century classic work Systema Naturae, Carl Linnaeus used cucullatus as the specific name, but combined it with the genus name Struthio (ostrich). Mathurin Jacques Brisson coined the genus name Raphus (referring to the bustards) in 1760, resulting in the current name Raphus cucullatus. In 1766, Linnaeus coined the new binomial Didus ineptus (meaning "inept dodo"). This has become a synonym of the earlier name because of nomenclatural priority.
As no complete dodo specimens exist, its external appearance, such as plumage and colouration, is hard to determine. Illustrations and written accounts of encounters with the dodo between its discovery and its extinction (1598–1662) are the primary evidence for its external appearance. According to most representations, the dodo had greyish or brownish plumage, with lighter primary feathers and a tuft of curly light feathers high on its rear end. The head was grey and naked, the beak green, black and yellow, and the legs were stout and yellowish, with black claws. A study of the few remaining feathers on the Oxford specimen head showed that they were pennaceous rather than plumaceous (downy) and most similar to those of other pigeons.
Subfossil remains and remnants of the birds that were brought to Europe in the 17th century show that dodos were very large birds, measuring around 62.6–75 cm (2.05–2.46 ft) in height. The bird was sexually dimorphic; males were larger and had proportionally longer beaks. Weight estimates have varied from study to study. In 1993, Bradley C. Livezey proposed that males would have weighed 21 kilograms (46 lb) and females 17 kilograms (37 lb). Also in 1993, Andrew C. Kitchener attributed a high contemporary weight estimate and the roundness of dodos depicted in Europe to these birds having been overfed in captivity; weights in the wild were estimated to have been in the range of 10.6–17.5 kg (23–39 lb), and fattened birds could have weighed 21.7–27.8 kg (48–61 lb). A 2011 estimate by Angst and colleagues gave an average weight as low as 10.2 kg (22 lb). This has also been questioned, and there is still controversy over weight estimates. A 2016 study estimated the weight at 10.6 to 14.3 kg (23 to 32 lb), based on CT scans of composite skeletons. It has also been suggested that the weight depended on the season, and that individuals were fat during cool seasons, but less so during hot.
The skull of the dodo differed much from those of other pigeons, especially in being more robust, the bill having a hooked tip, and in having a short cranium compared to the jaws. The upper bill was nearly twice as long as the cranium, which was short compared to those of its closest pigeon relatives. The openings of the bony nostrils were elongated along the length of the beak, and they contained no bony septum. The cranium (excluding the beak) was wider than it was long, and the frontal bone formed a dome-shape, with the highest point above the hind part of the eye sockets. The skull sloped downwards at the back. The eye sockets occupied much of the hind part of the skull. The sclerotic rings inside the eye were formed by eleven ossicles (small bones), similar to the amount in other pigeons. The mandible was slightly curved, and each half had a single fenestra (opening), as in other pigeons.
The dodo had about nineteen presynsacral vertebrae (those of the neck and thorax, including three fused into a notarium), sixteen synsacral vertebrae (those of the lumbar region and sacrum), six free tail (caudal) vertebrae, and a pygostyle. The neck had well-developed areas for muscle and ligament attachment, probably to support the heavy skull and beak. On each side, it had six ribs, four of which articulated with the sternum through sternal ribs. The sternum was large, but small in relation to the body compared to those of much smaller pigeons that are able to fly. The sternum was highly pneumatic, broad, and relatively thick in cross-section. The bones of the pectoral girdle, shoulder blades, and wing bones were reduced in size compared to those of flighted pigeon, and were more gracile compared to those of the Rodrigues solitaire, but none of the individual skeletal components had disappeared. The carpometacarpus of the dodo was more robust than that of the solitaire, however. The pelvis was wider than that of the solitaire and other relatives, yet was comparable to the proportions in some smaller, flighted pigeons. Most of the leg bones were more robust than those of extant pigeons and the solitaire, but the length proportions were little different.
Many of the skeletal features that distinguish the dodo and the Rodrigues solitaire, its closest relative, from other pigeons have been attributed to their flightlessness. The pelvic elements were thicker than those of flighted pigeons to support the higher weight, and the pectoral region and the small wings were paedomorphic, meaning that they were underdeveloped and retained juvenile features. The skull, trunk and pelvic limbs were peramorphic, meaning that they changed considerably with age. The dodo shared several other traits with the Rodrigues solitaire, such as features of the skull, pelvis, and sternum, as well as their large size. It differed in other aspects, such as being more robust and shorter than the solitaire, having a larger skull and beak, a rounded skull roof, and smaller orbits. The dodo's neck and legs were proportionally shorter, and it did not possess an equivalent to the knob present on the solitaire's wrists.
Most contemporary descriptions of the dodo are found in ship's logs and journals of the Dutch East India Company vessels that docked in Mauritius when the Dutch Empire ruled the island. These records were used as guides for future voyages. Few contemporary accounts are reliable, as many seem to be based on earlier accounts, and none were written by scientists. One of the earliest accounts, from van Warwijck's 1598 journal, describes the bird as follows:
Blue parrots are very numerous there, as well as other birds; among which are a kind, conspicuous for their size, larger than our swans, with huge heads only half covered with skin as if clothed with a hood. These birds lack wings, in the place of which 3 or 4 blackish feathers protrude. The tail consists of a few soft incurved feathers, which are ash coloured. These we used to call 'Walghvogel', for the reason that the longer and oftener they were cooked, the less soft and more insipid eating they became. Nevertheless their belly and breast were of a pleasant flavour and easily masticated.
One of the most detailed descriptions is by Herbert in A Relation of Some Yeares Travaille into Afrique and the Greater Asia from 1634:
First here only and in Dygarrois [Rodrigues] is generated the Dodo, which for shape and rareness may antagonize the Phoenix of Arabia: her body is round and fat, few weigh less than fifty pound. It is reputed more for wonder than for food, greasie stomackes may seeke after them, but to the delicate they are offensive and of no nourishment. Her visage darts forth melancholy, as sensible of Nature's injurie in framing so great a body to be guided with complementall wings, so small and impotent, that they serve only to prove her bird. The halfe of her head is naked seeming couered with a fine vaile, her bill is crooked downwards, in midst is the thrill [nostril], from which part to the end tis a light green, mixed with pale yellow tincture; her eyes are small and like to Diamonds, round and rowling; her clothing downy feathers, her train three small plumes, short and inproportionable, her legs suiting her body, her pounces sharpe, her appetite strong and greedy. Stones and iron are digested, which description will better be conceived in her representation.
The travel journal of the Dutch ship Gelderland (1601–1603), rediscovered in the 1860s, contains the only known sketches of living or recently killed specimens drawn on Mauritius. They have been attributed to the professional artist Joris Joostensz Laerle, who also drew other now-extinct Mauritian birds, and to a second, less refined artist. Apart from these sketches, it is unknown how many of the twenty or so 17th-century illustrations of the dodos were drawn from life or from stuffed specimens, which affects their reliability. Since dodos are otherwise only known from limited physical remains and descriptions, contemporary artworks are important to reconstruct their appearance in life. While there has been an effort since the mid-19 century to list all historical illustrations of dodos, previously unknown depictions continue to be discovered occasionally.
The traditional image of the dodo is of a very fat and clumsy bird, but this view may be exaggerated. The general opinion of scientists today is that many old European depictions were based on overfed captive birds or crudely stuffed specimens. It has also been suggested that the images might show dodos with puffed feathers, as part of display behaviour. The Dutch painter Roelant Savery was the most prolific and influential illustrator of the dodo, having made at least twelve depictions, often showing it in the lower corners. A famous painting of his from 1626, now called Edwards's Dodo as it was once owned by the ornithologist George Edwards, has since become the standard image of a dodo. It is housed in the Natural History Museum, London. The image shows a particularly fat bird and is the source for many other dodo illustrations.
An Indian Mughal painting rediscovered in the Hermitage Museum, St. Petersburg, in 1955 shows a dodo along with native Indian birds. It depicts a slimmer, brownish bird, and its discoverer Aleksander Iwanow and British palaeontologist Julian Hume regarded it as one of the most accurate depictions of the living dodo; the surrounding birds are clearly identifiable and depicted with appropriate colouring. It is believed to be from the 17th century and has been attributed to the Mughal painter Ustad Mansur. The bird depicted probably lived in the menagerie of the Mughal Emperor Jahangir, located in Surat, where the English traveller Peter Mundy also claimed to have seen two dodos sometime between 1628 and 1633. In 2014, another Indian illustration of a dodo was reported, but it was found to be derivative of an 1836 German illustration.
All post-1638 depictions appear to be based on earlier images, around the time reports mentioning dodos became rarer. Differences in the depictions led ornithologists such as Anthonie Cornelis Oudemans and Masauji Hachisuka to speculate about sexual dimorphism, ontogenic traits, seasonal variation, and even the existence of different species, but these theories are not accepted today. Because details such as markings of the beak, the form of the tail feathers, and colouration vary from account to account, it is impossible to determine the exact morphology of these features, whether they signal age or sex, or if they even reflect reality. Hume argued that the nostrils of the living dodo would have been slits, as seen in the Gelderland, Cornelis Saftleven, Savery's Crocker Art Gallery, and Mansur images. According to this claim, the gaping nostrils often seen in paintings indicate that taxidermy specimens were used as models. Most depictions show that the wings were held in an extended position, unlike flighted pigeons, but similar to ratites such as the ostrich and kiwi.
Little is known of the behaviour of the dodo, as most contemporary descriptions are very brief. Based on weight estimates, it has been suggested the male could reach the age of 21, and the female 17. Studies of the cantilever strength of its leg bones indicate that it could run quite fast. The legs were robust and strong to support the bulk of the bird, and also made it agile and manoeuvrable in the dense, pre-human landscape. Though the wings were small, well-developed muscle scars on the bones show that they were not completely vestigial, and may have been used for display behaviour and balance; extant pigeons also use their wings for such purposes. Unlike the Rodrigues solitaire, there is no evidence that the dodo used its wings in intraspecific combat. Though some dodo bones have been found with healed fractures, it had weak pectoral muscles and more reduced wings in comparison. The dodo may instead have used its large, hooked beak in territorial disputes. Since Mauritius receives more rainfall and has less seasonal variation than Rodrigues, which would have affected the availability of resources on the island, the dodo would have less reason to evolve aggressive territorial behaviour. The Rodrigues solitaire was therefore probably the more aggressive of the two. In 2016, the first 3D endocast was made from the brain of the dodo; the brain-to-body-size ratio was similar to that of modern pigeons, indicating that dodos were probably equal in intelligence.
The preferred habitat of the dodo is unknown, but old descriptions suggest that it inhabited the woods on the drier coastal areas of south and west Mauritius. This view is supported by the fact that the Mare aux Songes swamp, where most dodo remains have been excavated, is close to the sea in south-eastern Mauritius. Such a limited distribution across the island could well have contributed to its extinction. A 1601 map from the Gelderland journal shows a small island off the coast of Mauritius where dodos were caught. Julian Hume has suggested this island was l'île aux Benitiers in Tamarin Bay, on the west coast of Mauritius. Subfossil bones have also been found inside caves in highland areas, indicating that it once occurred on mountains. Work at the Mare aux Songes swamp has shown that its habitat was dominated by tambalacoque and Pandanus trees and endemic palms. The near-coastal placement and wetness of the Mare aux Songes led to a high diversity of plant species, whereas the surrounding areas were drier.
Many endemic species of Mauritius became extinct after the arrival of humans, so the ecosystem of the island is badly damaged and hard to reconstruct. Before humans arrived, Mauritius was entirely covered in forests, but very little remains of them today, because of deforestation. The surviving endemic fauna is still seriously threatened. The dodo lived alongside other recently extinct Mauritian birds such as the flightless red rail, the broad-billed parrot, the Mascarene grey parakeet, the Mauritius blue pigeon, the Mauritius scops owl, the Mascarene coot, the Mauritian shelduck, the Mauritian duck, and the Mauritius night heron. Extinct Mauritian reptiles include the saddle-backed Mauritius giant tortoise, the domed Mauritius giant tortoise, the Mauritian giant skink, and the Round Island burrowing boa. The small Mauritian flying fox and the snail Tropidophora carinata lived on Mauritius and Réunion, but vanished from both islands. Some plants, such as Casearia tinifolia and the palm orchid, have also become extinct.
A 1631 Dutch letter (long thought lost, but rediscovered in 2017) is the only account of the dodo's diet, and also mentions that it used its beak for defence. The document uses word-play to refer to the animals described, with dodos presumably being an allegory for wealthy mayors:
The mayors are superb and proud. They presented themselves with an unyielding, stern face and wide open mouth, very jaunty and audacious of gait. They did not want to budge before us; their war weapon was the mouth, with which they could bite fiercely. Their food was raw fruit; they were not dressed very well, but were rich and fat, therefore we brought many of them on board, to the contentment of us all.
In addition to fallen fruits, the dodo probably subsisted on nuts, seeds, bulbs, and roots. It has also been suggested that the dodo might have eaten crabs and shellfish, like their relatives the crowned pigeons. Its feeding habits must have been versatile, since captive specimens were probably given a wide range of food on the long sea journeys. Oudemans suggested that as Mauritius has marked dry and wet seasons, the dodo probably fattened itself on ripe fruits at the end of the wet season to survive the dry season, when food was scarce; contemporary reports describe the bird's "greedy" appetite. The Mauritian ornithologist France Staub suggested in 1996 that they mainly fed on palm fruits, and he attempted to correlate the fat-cycle of the dodo with the fruiting regime of the palms.
Skeletal elements of the upper jaw appear to have been rhynchokinetic (movable in relation to each other), which must have affected its feeding behaviour. In extant birds, such as frugivorous (fruit-eating) pigeons, kinetic premaxillae help with consuming large food items. The beak also appears to have been able to withstand high force loads, which indicates a diet of hard food. Examination of the brain endocast found that though the brain was similar to that of other pigeons in most respects, the dodo had a comparatively large olfactory bulb. This gave the dodo a good sense of smell, which may have aided in locating fruit and small prey.
Several contemporary sources state that the dodo used Gastroliths (gizzard stones) to aid digestion. The English writer Sir Hamon L'Estrange witnessed a live bird in London and described it as follows:
About 1638, as I walked London streets, I saw the picture of a strange looking fowle hung out upon a clothe and myselfe with one or two more in company went in to see it. It was kept in a chamber, and was a great fowle somewhat bigger than the largest Turkey cock, and so legged and footed, but stouter and thicker and of more erect shape, coloured before like the breast of a young cock fesan, and on the back of a dunn or dearc colour. The keeper called it a Dodo, and in the ende of a chymney in the chamber there lay a heape of large pebble stones, whereof hee gave it many in our sight, some as big as nutmegs, and the keeper told us that she eats them (conducing to digestion), and though I remember not how far the keeper was questioned therein, yet I am confident that afterwards she cast them all again.
It is not known how the young were fed, but related pigeons provide crop milk. Contemporary depictions show a large crop, which was probably used to add space for food storage and to produce crop milk. It has been suggested that the maximum size attained by the dodo and the solitaire was limited by the amount of crop milk they could produce for their young during early growth.
In 1973, the tambalacoque, also known as the dodo tree, was thought to be dying out on Mauritius, to which it is endemic. There were supposedly only 13 specimens left, all estimated to be about 300 years old. Stanley Temple hypothesised that it depended on the dodo for its propagation, and that its seeds would germinate only after passing through the bird's digestive tract. He claimed that the tambalacoque was now nearly coextinct because of the disappearance of the dodo. Temple overlooked reports from the 1940s that found that tambalacoque seeds germinated, albeit very rarely, without being abraded during digestion. Others have contested his hypothesis and suggested that the decline of the tree was exaggerated or seeds were also distributed by other extinct animals such as Cylindraspis tortoises, fruit bats, or the broad-billed parrot. According to Wendy Strahm and Anthony Cheke, two experts in the ecology of the Mascarene Islands, the tree, while rare, has germinated since the demise of the dodo and numbers several hundred, not 13 as claimed by Temple, hence, discrediting Temple's view as to the dodo and the tree's sole survival relationship.
The Brazilian ornithologist Carlos Yamashita suggested in 1997 that the broad-billed parrot may have depended on dodos and Cylindraspis tortoises to eat palm fruits and excrete their seeds, which became food for the parrots. Anodorhynchus macaws depended on now-extinct South American megafauna in the same way, but now rely on domesticated cattle for this service.
As it was flightless and terrestrial and there were no mammalian predators or other kinds of natural enemy on Mauritius, the dodo probably nested on the ground. The account by François Cauche from 1651 is the only description of the egg and the call:
I have seen in Mauritius birds bigger than a Swan, without feathers on the body, which is covered with a black down; the hinder part is round, the rump adorned with curled feathers as many in number as the bird is years old. In place of wings they have feathers like these last, black and curved, without webs. They have no tongues, the beak is large, curving a little downwards; their legs are long, scaly, with only three toes on each foot. It has a cry like a gosling, and is by no means so savoury to eat as the Flamingos and Ducks of which we have just spoken. They only lay one egg which is white, the size of a halfpenny roll, by the side of which they place a white stone the size of a hen's egg. They lay on grass which they collect, and make their nests in the forests; if one kills the young one, a grey stone is found in the gizzard. We call them Oiseaux de Nazaret. The fat is excellent to give ease to the muscles and nerves.
Cauche's account is problematic, since it also mentions that the bird he was describing had three toes and no tongue, unlike dodos. This led some to believe that Cauche was describing a new species of dodo ("Didus nazarenus"). The description was most probably mingled with that of a cassowary, and Cauche's writings have other inconsistencies. A mention of a "young ostrich" taken on board a ship in 1617 is the only other reference to a possible juvenile dodo. An egg claimed to be that of a dodo is stored in the East London Museum in South Africa. It was donated by the South African museum official Marjorie Courtenay-Latimer, whose great aunt had received it from a captain who claimed to have found it in a swamp on Mauritius. In 2010, the curator of the museum proposed using genetic studies to determine its authenticity. It may instead be an aberrant ostrich egg.
Because of the possible single-egg clutch and the bird's large size, it has been proposed that the dodo was K-selected, meaning that it produced few altricial offspring, which required parental care until they matured. Some evidence, including the large size and the fact that tropical and frugivorous birds have slower growth rates, indicates that the bird may have had a protracted development period. The fact that no juvenile dodos have been found in the Mare aux Songes swamp may indicate that they produced little offspring, that they matured rapidly, that the breeding grounds were far away from the swamp, or that the risk of miring was seasonal.
A 2017 study examined the histology of thin-sectioned dodo bones, modern Mauritian birds, local ecology, and contemporary accounts, to recover information about the life history of the dodo. The study suggested that dodos bred around August, after having potentially fattened themselves, corresponding with the fat and thin cycles of many vertebrates of Mauritius. The chicks grew rapidly, reaching robust, almost adult, sizes, and sexual maturity before Austral summer or the cyclone season. Adult dodos which had just bred moulted after Austral summer, around March. The feathers of the wings and tail were replaced first, and the moulting would have completed at the end of July, in time for the next breeding season. Different stages of moulting may also account for inconsistencies in contemporary descriptions of dodo plumage.
Mauritius had previously been visited by Arab vessels in the Middle Ages and Portuguese ships between 1507 and 1513, but was settled by neither. No records of dodos by these are known, although the Portuguese name for Mauritius, "Cerne (swan) Island", may have been a reference to dodos. The Dutch Empire acquired Mauritius in 1598, renaming it after Maurice of Nassau, and it was used for the provisioning of trade vessels of the Dutch East India Company henceforward. The earliest known accounts of the dodo were provided by Dutch travellers during the Second Dutch Expedition to Indonesia, led by admiral Jacob van Neck in 1598. They appear in reports published in 1601, which also contain the first published illustration of the bird. Since the first sailors to visit Mauritius had been at sea for a long time, their interest in these large birds was mainly culinary. The 1602 journal by Willem Van West-Zanen of the ship Bruin-Vis mentions that 24–25 dodos were hunted for food, which were so large that two could scarcely be consumed at mealtime, their remains being preserved by salting. An illustration made for the 1648 published version of this journal, showing the killing of dodos, a dugong, and possibly Mascarene grey parakeets, was captioned with a Dutch poem, here in Hugh Strickland's 1848 translation:
For food the seamen hunt the flesh of feathered fowl, They tap the palms, and round-rumped dodos they destroy, The parrot's life they spare that he may peep and howl, And thus his fellows to imprisonment decoy.
Some early travellers found dodo meat unsavoury, and preferred to eat parrots and pigeons; others described it as tough, but good. Some hunted dodos only for their gizzards, as this was considered the most delicious part of the bird. Dodos were easy to catch, but hunters had to be careful not to be bitten by their powerful beaks.
The appearance of the dodo and the red rail led Peter Mundy to speculate, 230 years before Charles Darwin's theory of evolution:
Of these 2 sorts off fowl afforementionede, For oughtt wee yett know, Not any to bee Found out of this Iland, which lyeth aboutt 100 leagues From St. Lawrence. A question may bee demaunded how they should bee here and Not elcewhere, beeing soe Farer From other land and can Neither fly or swymme; whither by Mixture off kindes producing straunge and Monstrous formes, or the Nature of the Climate, ayer and earth in alltring the First shapes in long tyme, or how.
The dodo was found interesting enough that living specimens were sent to Europe and the East. The number of transported dodos that reached their destinations alive is uncertain, and it is unknown how they relate to contemporary depictions and the few non-fossil remains in European museums. Based on a combination of contemporary accounts, paintings, and specimens, Julian Hume has inferred that at least eleven transported dodos reached their destinations alive.
Hamon L'Estrange's description of a dodo that he saw in London in 1638 is the only account that specifically mentions a live specimen in Europe. In 1626 Adriaen van de Venne drew a dodo that he claimed to have seen in Amsterdam, but he did not mention if it was alive, and his depiction is reminiscent of Savery's Edwards's Dodo. Two live specimens were seen by Peter Mundy in Surat, India, between 1628 and 1634, one of which may have been the individual painted by Mansur around 1625. In 1628, Emmanuel Altham visited Mauritius and sent a letter to his brother in England:
Right wo and lovinge brother, we were ordered by ye said councell to go to an island called Mauritius, lying in 20d. of south latt., where we arrived ye 28th of May; this island having many goates, hogs and cowes upon it, and very strange fowles, called by ye portingalls Dodo, which for the rareness of the same, the like being not in ye world but here, I have sent you one by Mr. Perce, who did arrive with the ship William at this island ye 10th of June. [In the margin of the letter] Of Mr. Perce you shall receive a jarr of ginger for my sister, some beades for my cousins your daughters, and a bird called a Dodo, if it live.
Whether the dodo survived the journey is unknown, and the letter was destroyed by fire in the 19th century. The earliest known picture of a dodo specimen in Europe is from a c. 1610 collection of paintings depicting animals in the royal menagerie of Emperor Rudolph II in Prague. This collection includes paintings of other Mauritian animals as well, including a red rail. The dodo, which may be a juvenile, seems to have been dried or embalmed, and had probably lived in the emperor's zoo for a while together with the other animals. That whole stuffed dodos were present in Europe indicates they had been brought alive and died there; it is unlikely that taxidermists were on board the visiting ships, and spirits were not yet used to preserve biological specimens. Most tropical specimens were preserved as dried heads and feet.
One dodo was reportedly sent as far as Nagasaki, Japan, in 1647, but it was long unknown whether it arrived. Contemporary documents first published in 2014 proved the story, and showed that it had arrived alive. It was meant as a gift, and, despite its rarity, was considered of equal value to a white deer and a bezoar stone. It is the last recorded live dodo in captivity.
Like many animals that evolved in isolation from significant predators, the dodo was entirely fearless of humans. This fearlessness and its inability to fly made the dodo easy prey for sailors. Although some scattered reports describe mass killings of dodos for ships' provisions, archaeological investigations have found scant evidence of human predation. Bones of at least two dodos were found in caves at Baie du Cap that sheltered fugitive slaves and convicts in the 17th century, which would not have been easily accessible to dodos because of the high, broken terrain. The human population on Mauritius (an area of 1,860 km or 720 sq mi) never exceeded 50 people in the 17th century, but they introduced other animals, including dogs, pigs, cats, rats, and crab-eating macaques, which plundered dodo nests and competed for the limited food resources. At the same time, humans destroyed the forest habitat of the dodos. The impact of the introduced animals on the dodo population, especially the pigs and macaques, is today considered more severe than that of hunting. Rats were perhaps not much of a threat to the nests, since dodos would have been used to dealing with local land crabs.
It has been suggested that the dodo may already have been rare or localised before the arrival of humans on Mauritius, since it would have been unlikely to become extinct so rapidly if it had occupied all the remote areas of the island. A 2005 expedition found subfossil remains of dodos and other animals killed by a flash flood. Such mass mortalities would have further jeopardised a species already in danger of becoming extinct. Yet the fact that the dodo survived hundreds of years of volcanic activity and climatic changes shows the bird was resilient within its ecosystem.
Some controversy surrounds the date of its extinction. The last widely accepted record of a dodo sighting is the 1662 report by shipwrecked mariner Volkert Evertsz of the Dutch ship Arnhem, who described birds caught on a small islet off Mauritius, now suggested to be Amber Island:
These animals on our coming up to them stared at us and remained quiet where they stand, not knowing whether they had wings to fly away or legs to run off, and suffering us to approach them as close as we pleased. Amongst these birds were those which in India they call Dod-aersen (being a kind of very big goose); these birds are unable to fly, and instead of wings, they merely have a few small pins, yet they can run very swiftly. We drove them together into one place in such a manner that we could catch them with our hands, and when we held one of them by its leg, and that upon this it made a great noise, the others all on a sudden came running as fast as they could to its assistance, and by which they were caught and made prisoners also.
The dodos on this islet may not necessarily have been the last members of the species. The last claimed sighting of a dodo was reported in the hunting records of Isaac Johannes Lamotius in 1688. A 2003 statistical analysis of these records by the biologists David L. Roberts and Andrew R. Solow gave a new estimated extinction date of 1693, with a 95% confidence interval of 1688–1715. These authors also pointed out that because the last sighting before 1662 was in 1638, the dodo was probably already quite rare by the 1660s, and thus a disputed report from 1674 by an escaped slave could not be dismissed out of hand.
The British ornithologist Alfred Newton suggested in 1868 that the name of the dodo was transferred to the red rail after the former had gone extinct. Cheke also pointed out that some descriptions after 1662 use the names "Dodo" and "Dodaers" when referring to the red rail, indicating that they had been transferred to it. He therefore pointed to the 1662 description as the last credible observation. A 1668 account by English traveller John Marshall, who used the names "Dodo" and "Red Hen" interchangeably for the red rail, mentioned that the meat was "hard", which echoes the description of the meat in the 1681 account. Even the 1662 account has been questioned by the writer Errol Fuller, as the reaction to distress cries matches what was described for the red rail. Until this explanation was proposed, a description of "dodos" from 1681 was thought to be the last account, and that date still has proponents.
Cheke stated in 2014 that then recently accessible Dutch manuscripts indicate that no dodos were seen by settlers in 1664–1674. In 2020, Cheke and the British researcher Jolyon C. Parish suggested that all mentions of dodos after the mid-17th century instead referred to red rails, and that the dodo had disappeared due to predation by feral pigs during a hiatus in settlement of Mauritius (1658–1664). The dodo's extinction therefore was not realised at the time, since new settlers had not seen real dodos, but as they expected to see flightless birds, they referred to the red rail by that name instead. Since red rails probably had larger clutches than dodos and their eggs could be incubated faster, and their nests were perhaps concealed, they probably bred more efficiently, and were less vulnerable to pigs.
It is unlikely the issue will ever be resolved, unless late reports mentioning the name alongside a physical description are rediscovered. The IUCN Red List accepts Cheke's rationale for choosing the 1662 date, taking all subsequent reports to refer to red rails. In any case, the dodo was probably extinct by 1700, about a century after its discovery in 1598. The Dutch left Mauritius in 1710, but by then the dodo and most of the large terrestrial vertebrates there had become extinct.
Even though the rareness of the dodo was reported already in the 17th century, its extinction was not recognised until the 19th century. This was partly because, for religious reasons, extinction was not believed possible until later proved so by Georges Cuvier, and partly because many scientists doubted that the dodo had ever existed. It seemed altogether too strange a creature, and many believed it a myth. The bird was first used as an example of human-induced extinction in Penny Magazine in 1833, and has since been referred to as an "icon" of extinction.
The only extant remains of dodos taken to Europe in the 17th century are a dried head and foot in the Oxford University Museum of Natural History, a foot once housed in the British Museum but now lost, a skull in the University of Copenhagen Zoological Museum, and an upper jaw in the National Museum, Prague. The last two were rediscovered and identified as dodo remains in the mid-19th century. Several stuffed dodos were also mentioned in old museum inventories, but none are known to have survived. Apart from these remains, a dried foot, which belonged to the Dutch professor Pieter Pauw, was mentioned by Carolus Clusius in 1605. Its provenance is unknown, and it is now lost, but it may have been collected during the Van Neck voyage. Supposed stuffed dodos seen in museums around the world today have in fact been made from feathers of other birds, many of the older ones by the British taxidermist Rowland Ward's company.
The only known soft tissue remains, the Oxford head (specimen OUM 11605) and foot, belonged to the last known stuffed dodo, which was first mentioned as part of the Tradescant collection in 1656 and was moved to the Ashmolean Museum in 1659. It has been suggested that this might be the remains of the bird that Hamon L'Estrange saw in London, the bird sent by Emanuel Altham, or a donation by Thomas Herbert. Since the remains do not show signs of having been mounted, the specimen might instead have been preserved as a study skin. In 2018, it was reported that scans of the Oxford dodo's head showed that its skin and bone contained lead shot, pellets which were used to hunt birds in the 17th century. This indicates that the Oxford dodo was shot either before being transported to Britain, or some time after arriving. The circumstances of its killing are unknown, and the pellets are to be examined to identify where the lead was mined from.
Many sources state that the Ashmolean Museum burned the stuffed dodo around 1755 because of severe decay, saving only the head and leg. Statute 8 of the museum states "That as any particular grows old and perishing the keeper may remove it into one of the closets or other repository; and some other to be substituted." The deliberate destruction of the specimen is now believed to be a myth; it was removed from exhibition to preserve what remained of it. This remaining soft tissue has since degraded further; the head was dissected by Strickland and Melville, separating the skin from the skull in two-halves. The foot is in a skeletal state, with only scraps of skin and tendons. Very few feathers remain on the head. It is probably a female, as the foot is 11% smaller and more gracile than the London foot, yet appears to be fully grown. The specimen was exhibited at the Oxford museum from at least the 1860s and until 1998, where-after it was mainly kept in storage to prevent damage. Casts of the head can today be found in many museums worldwide.
The dried London foot, first mentioned in 1665, and transferred to the British Museum in the 18th century, was displayed next to Savery's Edwards's Dodo painting until the 1840s, and it too was dissected by Strickland and Melville. It was not posed in a standing posture, which suggests that it was severed from a fresh specimen, not a mounted one. By 1896 it was mentioned as being without its integuments, and only the bones are believed to remain today, though its present whereabouts are unknown.
The Copenhagen skull (specimen ZMUC 90-806) is known to have been part of the collection of Bernardus Paludanus in Enkhuizen until 1651, when it was moved to the museum in Gottorf Castle, Schleswig. After the castle was occupied by Danish forces in 1702, the museum collection was assimilated into the Royal Danish collection. The skull was rediscovered by J. T. Reinhardt in 1840. Based on its history, it may be the oldest known surviving remains of a dodo brought to Europe in the 17th century. It is 13 mm (0.51 in) shorter than the Oxford skull, and may have belonged to a female. It was mummified, but the skin has perished.
The front part of a skull (specimen NMP P6V-004389) in the National Museum of Prague was found in 1850 among the remains of the Böhmisches Museum. Other elements supposedly belonging to this specimen have been listed in the literature, but it appears only the partial skull was ever present (a partial right limb in the museum appears to be from a Rodrigues solitaire). It may be what remains of one of the stuffed dodos known to have been at the menagerie of Emperor Rudolph II, possibly the specimen painted by Hoefnagel or Savery there.
Until 1860, the only known dodo remains were the four incomplete 17th-century specimens. Philip Burnard Ayres found the first subfossil bones in 1860, which were sent to Richard Owen at the British Museum, who did not publish the findings. In 1863, Owen requested the Mauritian Bishop Vincent Ryan to spread word that he should be informed if any dodo bones were found. In 1865, George Clark, the government schoolmaster at Mahébourg, finally found an abundance of subfossil dodo bones in the swamp of Mare aux Songes in Southern Mauritius, after a 30-year search inspired by Strickland and Melville's monograph. In 1866, Clark explained his procedure to The Ibis, an ornithology journal: he had sent his coolies to wade through the centre of the swamp, feeling for bones with their feet. At first they found few bones, until they cut away herbage that covered the deepest part of the swamp, where they found many fossils. Harry Pasley Higginson, a railway engineer from Yorkshire, reports discovering the Mare aux Songes bones at the same time as Clark and there is some dispute over who found them first. Higginson sent boxes of these bones to Liverpool, Leeds and York museums. The swamp yielded the remains of over 300 dodos, but very few skull and wing bones, possibly because the upper bodies were washed away or scavenged while the lower body was trapped. The situation is similar to many finds of moa remains in New Zealand marshes. Most dodo remains from the Mare aux Songes have a medium to dark brown colouration.
Clark's reports about the finds rekindled interest in the bird. Sir Richard Owen and Alfred Newton both wanted to be first to describe the post-cranial anatomy of the dodo, and Owen bought a shipment of dodo bones originally meant for Newton, which led to rivalry between the two. Owen described the bones in Memoir on the Dodo in October 1866, but erroneously based his reconstruction on the Edwards's Dodo painting by Savery, making it too squat and obese. In 1869 he received more bones and corrected its stance, making it more upright. Newton moved his focus to the Réunion solitaire instead. The remaining bones not sold to Owen or Newton were auctioned off or donated to museums. In 1889, Théodor Sauzier was commissioned to explore the "historical souvenirs" of Mauritius and find more dodo remains in the Mare aux Songes. He was successful, and also found remains of other extinct species.
In 2005, after a hundred years of neglect, a part of the Mare aux Songes swamp was excavated by an international team of researchers (International Dodo Research Project). To prevent malaria, the British had covered the swamp with hard core during their rule over Mauritius, which had to be removed. Many remains were found, including bones of at least 17 dodos in various stages of maturity (though no juveniles), and several bones obviously from the skeleton of one individual bird, which have been preserved in their natural position. These findings were made public in December 2005 in the Naturalis museum in Leiden. 63% of the fossils found in the swamp belonged to turtles of the extinct genus Cylindraspis, and 7.1% belonged to dodos, which had been deposited within several centuries, 4,000 years ago. Subsequent excavations suggested that dodos and other animals became mired in the Mare aux Songes while trying to reach water during a long period of severe drought about 4,200 years ago. Furthermore, cyanobacteria thrived in the conditions created by the excrements of animals gathered around the swamp, which died of intoxication, dehydration, trampling, and miring. Though many small skeletal elements were found during the recent excavations of the swamp, few were found during the 19th century, probably owing to the employment of less refined methods when collecting.
Louis Etienne Thirioux, an amateur naturalist at Port Louis, also found many dodo remains around 1900 from several locations. They included the first articulated specimen, which is the first subfossil dodo skeleton found outside the Mare aux Songes, and the only remains of a juvenile specimen, a now lost tarsometatarsus. The former specimen was found in 1904 in a cave near Le Pouce mountain, and is the only known complete skeleton of an individual dodo. Thirioux donated the specimen to the Museum Desjardins (now Natural History Museum at Mauritius Institute). Thrioux's heirs sold a second mounted composite skeleton (composed of at least two skeletons, with a mainly reconstructed skull) to the Durban Museum of Natural Science in South Africa in 1918. Together, these two skeletons represent the most completely known dodo remains, including bone elements previously unrecorded (such as knee-caps and wing bones). Though some contemporary writers noted the importance of Thrioux's specimens, they were not scientifically studied, and were largely forgotten until 2011, when sought out by a group of researchers. The mounted skeletons were laser scanned, from which 3-D models were reconstructed, which became the basis of a 2016 monograph about the osteology of the dodo. In 2006, explorers discovered a complete skeleton of a dodo in a lava cave in Mauritius. This was only the second associated skeleton of an individual specimen ever found, and the only one in recent times.
Worldwide, 26 museums have significant holdings of dodo material, almost all found in the Mare aux Songes. The Natural History Museum, American Museum of Natural History, Cambridge University Museum of Zoology, the Senckenberg Museum, and others have almost complete skeletons, assembled from the dissociated subfossil remains of several individuals. In 2011, a wooden box containing dodo bones from the Edwardian era was rediscovered at the Grant Museum at University College London during preparations for a move. They had been stored with crocodile bones until then.
The supposed "white dodo" (or "solitaire") of Réunion is now considered an erroneous conjecture based on contemporary reports of the Réunion ibis and 17th-century paintings of white, dodo-like birds by Pieter Withoos and Pieter Holsteyn that surfaced in the 19th century. The confusion began when Willem Ysbrandtszoon Bontekoe, who visited Réunion around 1619, mentioned fat, flightless birds that he referred to as "Dod-eersen" in his journal, though without mentioning their colouration. When the journal was published in 1646, it was accompanied by an engraving of a dodo from Savery's "Crocker Art Gallery sketch". A white, stocky, and flightless bird was first mentioned as part of the Réunion fauna by Chief Officer J. Tatton in 1625. Sporadic mentions were subsequently made by Sieur Dubois and other contemporary writers.
Baron Edmond de Sélys Longchamps coined the name Raphus solitarius for these birds in 1848, as he believed the accounts referred to a species of dodo. When 17th-century paintings of white dodos were discovered by 19th-century naturalists, it was assumed they depicted these birds. Oudemans suggested that the discrepancy between the paintings and the old descriptions was that the paintings showed females, and that the species was therefore sexually dimorphic. Some authors also believed the birds described were of a species similar to the Rodrigues solitaire, as it was referred to by the same name, or even that there were white species of both dodo and solitaire on the island.
The Pieter Withoos painting, which was discovered first, appears to be based on an earlier painting by Pieter Holsteyn, three versions of which are known to have existed. According to Hume, Cheke, and Valledor de Lozoya, it appears that all depictions of white dodos were based on Roelant Savery's painting Landscape with Orpheus and the animals, or on copies of it. The painting has generally been dated to 1611, though a post-1614, or even post-1626, date has also been proposed. The painting shows a whitish specimen and was apparently based on a stuffed specimen then in Prague; a walghvogel described as having a "dirty off-white colouring" was mentioned in an inventory of specimens in the Prague collection of the Holy Roman Emperor Rudolf II, to whom Savery was contracted at the time (1607–1611). Savery's several later images all show greyish birds, possibly because he had by then seen another specimen. Cheke and Hume believe the painted specimen was white, owing to albinism. Valledor de Lozoya has instead suggested that the light plumage was a juvenile trait, a result of bleaching of old taxidermy specimens, or simply artistic license.
In 1987, scientists described fossils of a recently extinct species of ibis from Réunion with a relatively short beak, Borbonibis latipes, before a connection to the solitaire reports had been made. Cheke suggested to one of the authors, Francois Moutou, that the fossils may have been of the Réunion solitaire, and this suggestion was published in 1995. The ibis was reassigned to the genus Threskiornis, now combined with the specific epithet solitarius from the binomial R. solitarius. Birds of this genus are also white and black with slender beaks, fitting the old descriptions of the Réunion solitaire. No fossil remains of dodo-like birds have ever been found on the island.
The dodo's significance as one of the best-known extinct animals and its singular appearance led to its use in literature and popular culture as a symbol of an outdated concept or object, as in the expression "dead as a dodo," which has come to mean unquestionably dead or obsolete. Similarly, the phrase "to go the way of the dodo" means to become extinct or obsolete, to fall out of common usage or practice, or to become a thing of the past. "Dodo" is also a slang term for a stupid, dull-witted person, as it was said to be stupid and easily caught.
The dodo appears frequently in works of popular fiction, and even before its extinction, it was featured in European literature, as a symbol for exotic lands, and of gluttony, due to its apparent fatness. In 1865, the same year that George Clark started to publish reports about excavated dodo fossils, the newly vindicated bird was featured as a character in Lewis Carroll's Alice's Adventures in Wonderland. It is thought that he included the dodo because he identified with it and had adopted the name as a nickname for himself because of his stammer, which made him accidentally introduce himself as "Do-do-dodgson", his legal surname. Carroll and the girl who served as inspiration for Alice, Alice Liddell, had enjoyed visiting the Oxford museum to see the dodo remains there. The book's popularity made the dodo a well-known icon of extinction. Popular depictions of the dodo often became more exaggerated and cartoonish following its Alice in Wonderland fame, which was in line with the inaccurate belief that it was clumsy, tragic, and destined for extinction.
The dodo is used as a mascot for many kinds of products, especially in Mauritius. It appears as a supporter on the coat of arms of Mauritius, on Mauritius coins, is used as a watermark on all Mauritian rupee banknotes, and features as the background of the Mauritian immigration form. A smiling dodo is the symbol of the Brasseries de Bourbon, a popular brewer on Réunion, whose emblem displays the white species once thought to have lived there.
The dodo is used to promote the protection of endangered species by environmental organisations, such as the Durrell Wildlife Conservation Trust and the Durrell Wildlife Park. The Center for Biological Diversity gives an annual 'Rubber Dodo Award', to "those who have done the most to destroy wild places, species and biological diversity". In 2011, the nephiline spider Nephilengys dodo, which inhabits the same woods as the dodo once did, was named after the bird to raise awareness of the urgent need for protection of the Mauritius biota. Two species of ant from Mauritius have been named after the dodo: Pseudolasius dodo in 1946 and Pheidole dodo in 2013. A species of isopod from a coral reef off Réunion was named Hansenium dodo in 1991.
The name dodo has been used by scientists naming genetic elements, honouring the dodo's flightless nature. A fruitfly gene within a region of a chromosome required for flying ability was named "dodo". In addition, a defective transposable element family from Phytophthora infestans was named DodoPi as it contained mutations that eliminated the element's ability to jump to new locations in a chromosome.
In 2009, a previously unpublished 17th-century Dutch illustration of a dodo went for sale at Christie's and was expected to sell for £6,000. It is unknown whether the illustration was based on a specimen or on a previous image, and the artist is unidentified. It sold for £44,450. Parrish suggested it depicts a stuffed specimen, as the legs look dried.
The poet Hilaire Belloc included the following poem about the dodo in his Bad Child's Book of Beasts from 1896:
The Dodo used to walk around, And take the sun and air. The sun yet warms his native ground – The Dodo is not there!
The voice which used to squawk and squeak Is now for ever dumb – Yet may you see his bones and beak All in the Mu-se-um. | [
{
"paragraph_id": 0,
"text": "The dodo (Raphus cucullatus) is an extinct flightless bird that was endemic to the island of Mauritius, which is east of Madagascar in the Indian Ocean. The dodo's closest relative was the also-extinct and flightless Rodrigues solitaire. The two formed the subfamily Raphinae, a clade of extinct flightless birds that were a part of the family which includes pigeons and doves. The closest living relative of the dodo is the Nicobar pigeon. A white dodo was once thought to have existed on the nearby island of Réunion, but it is now believed that this assumption was merely confusion based on the also-extinct Réunion ibis and paintings of white dodos.",
"title": ""
},
{
"paragraph_id": 1,
"text": "Subfossil remains show the dodo measured around 62.6–75 centimetres (2.05–2.46 ft) in height and may have weighed 10.6–17.5 kg (23–39 lb) in the wild. The dodo's appearance in life is evidenced only by drawings, paintings, and written accounts from the 17th century. Since these portraits vary considerably, and since only some of the illustrations are known to have been drawn from live specimens, the dodos' exact appearance in life remains unresolved, and little is known about its behaviour. It has been depicted with brownish-grey plumage, yellow feet, a tuft of tail feathers, a grey, naked head, and a black, yellow, and green beak. It used gizzard stones to help digest its food, which is thought to have included fruits, and its main habitat is believed to have been the woods in the drier coastal areas of Mauritius. One account states its clutch consisted of a single egg. It is presumed that the dodo became flightless because of the ready availability of abundant food sources and a relative absence of predators on Mauritius. Though the dodo has historically been portrayed as being fat and clumsy, it is now thought to have been well-adapted for its ecosystem.",
"title": ""
},
{
"paragraph_id": 2,
"text": "The first recorded mention of the dodo was by Dutch sailors in 1598. In the following years, the bird was hunted by sailors and invasive species, while its habitat was being destroyed. The last widely accepted sighting of a dodo was in 1662. Its extinction was not immediately noticed, and some considered the bird to be a myth. In the 19th century, research was conducted on a small quantity of remains of four specimens that had been brought to Europe in the early 17th century. Among these is a dried head, the only soft tissue of the dodo that remains today. Since then, a large amount of subfossil material has been collected on Mauritius, mostly from the Mare aux Songes swamp. The extinction of the dodo within less than a century of its discovery called attention to the previously unrecognised problem of human involvement in the disappearance of entire species. The dodo achieved widespread recognition from its role in the story of Alice's Adventures in Wonderland, and it has since become a fixture in popular culture, often as a symbol of extinction and obsolescence.",
"title": ""
},
{
"paragraph_id": 3,
"text": "The dodo was variously declared a small ostrich, a rail, an albatross, or a vulture, by early scientists. In 1842, Danish zoologist Johannes Theodor Reinhardt proposed that dodos were ground pigeons, based on studies of a dodo skull he had discovered in the collection of the Natural History Museum of Denmark. This view was met with ridicule, but was later supported by English naturalists Hugh Edwin Strickland and Alexander Gordon Melville in their 1848 monograph The Dodo and Its Kindred, which attempted to separate myth from reality. After dissecting the preserved head and foot of the specimen at the Oxford University Museum and comparing it with the few remains then available of the extinct Rodrigues solitaire (Pezophaps solitaria) they concluded that the two were closely related. Strickland stated that although not identical, these birds shared many distinguishing features of the leg bones, otherwise known only in pigeons.",
"title": "Taxonomy"
},
{
"paragraph_id": 4,
"text": "Strickland and Melville established that the dodo was anatomically similar to pigeons in many features. They pointed to the very short keratinous portion of the beak, with its long, slender, naked basal part. Other pigeons also have bare skin around their eyes, almost reaching their beak, as in dodos. The forehead was high in relation to the beak, and the nostril was located low on the middle of the beak and surrounded by skin, a combination of features shared only with pigeons. The legs of the dodo were generally more similar to those of terrestrial pigeons than of other birds, both in their scales and in their skeletal features. Depictions of the large crop hinted at a relationship with pigeons, in which this feature is more developed than in other birds. Pigeons generally have very small clutches, and the dodo is said to have laid a single egg. Like pigeons, the dodo lacked the vomer and septum of the nostrils, and it shared details in the mandible, the zygomatic bone, the palate, and the hallux. The dodo differed from other pigeons mainly in the small size of the wings and the large size of the beak in proportion to the rest of the cranium.",
"title": "Taxonomy"
},
{
"paragraph_id": 5,
"text": "Throughout the 19th century, several species were classified as congeneric with the dodo, including the Rodrigues solitaire and the Réunion solitaire, as Didus solitarius and Raphus solitarius, respectively (Didus and Raphus being names for the dodo genus used by different authors of the time). An atypical 17th-century description of a dodo and bones found on Rodrigues, now known to have belonged to the Rodrigues solitaire, led Abraham Dee Bartlett to name a new species, Didus nazarenus, in 1852. Based on solitaire remains, it is now a synonym of that species. Crude drawings of the red rail of Mauritius were also misinterpreted as dodo species; Didus broeckii and Didus herberti.",
"title": "Taxonomy"
},
{
"paragraph_id": 6,
"text": "For many years the dodo and the Rodrigues solitaire were placed in a family of their own, the Raphidae (formerly Dididae), because their exact relationships with other pigeons were unresolved. Each was also placed in its own monotypic family (Raphidae and Pezophapidae, respectively), as it was thought that they had evolved their similarities independently. Osteological and DNA analysis has since led to the dissolution of the family Raphidae, and the dodo and solitaire are now placed in their own subfamily, Raphinae, within the family Columbidae.",
"title": "Taxonomy"
},
{
"paragraph_id": 7,
"text": "In 2002, American geneticist Beth Shapiro and colleagues analysed the DNA of the dodo for the first time. Comparison of mitochondrial cytochrome b and 12S rRNA sequences isolated from a tarsal of the Oxford specimen and a femur of a Rodrigues solitaire confirmed their close relationship and their placement within the Columbidae. The genetic evidence was interpreted as showing the Southeast Asian Nicobar pigeon (Caloenas nicobarica) to be their closest living relative, followed by the crowned pigeons (Goura) of New Guinea, and the superficially dodo-like tooth-billed pigeon (Didunculus strigirostris) from Samoa (its scientific name refers to its dodo-like beak). This clade consists of generally ground-dwelling island endemic pigeons. The following cladogram shows the dodo's closest relationships within the Columbidae, based on Shapiro and colleagues, 2002:",
"title": "Taxonomy"
},
{
"paragraph_id": 8,
"text": "A similar cladogram was published in 2007, inverting the placement of Goura and Didunculus and including the pheasant pigeon (Otidiphaps nobilis) and the thick-billed ground pigeon (Trugon terrestris) at the base of the clade. The DNA used in these studies was obtained from the Oxford specimen, and since this material is degraded, and no usable DNA has been extracted from subfossil remains, these findings still need to be independently verified. Based on behavioural and morphological evidence, Jolyon C. Parish proposed that the dodo and Rodrigues solitaire should be placed in the subfamily Gourinae along with the Goura pigeons and others, in agreement with the genetic evidence. In 2014, DNA of the only known specimen of the recently extinct spotted green pigeon (Caloenas maculata) was analysed, and it was found to be a close relative of the Nicobar pigeon, and thus also the dodo and Rodrigues solitaire.",
"title": "Taxonomy"
},
{
"paragraph_id": 9,
"text": "The 2002 study indicated that the ancestors of the dodo and the solitaire diverged around the Paleogene-Neogene boundary, about 23.03 million years ago. The Mascarene Islands (Mauritius, Réunion, and Rodrigues), are of volcanic origin and are less than 10 million years old. Therefore, the ancestors of both birds probably remained capable of flight for a considerable time after the separation of their lineage. The Nicobar and spotted green pigeon were placed at the base of a lineage leading to the Raphinae, which indicates the flightless raphines had ancestors that were able to fly, were semi-terrestrial, and inhabited islands. This in turn supports the hypothesis that the ancestors of those birds reached the Mascarene islands by island hopping from South Asia. The lack of mammalian herbivores competing for resources on these islands allowed the solitaire and the dodo to attain very large sizes and flightlessness. Despite its divergent skull morphology and adaptations for larger size, many features of its skeleton remained similar to those of smaller, flying pigeons. Another large, flightless pigeon, the Viti Levu giant pigeon (Natunaornis gigoura), was described in 2001 from subfossil material from Fiji. It was only slightly smaller than the dodo and the solitaire, and it too is thought to have been related to the crowned pigeons.",
"title": "Taxonomy"
},
{
"paragraph_id": 10,
"text": "One of the original names for the dodo was the Dutch \"Walghvoghel\", first used in the journal of Dutch Vice Admiral Wybrand van Warwijck, who visited Mauritius during the Second Dutch Expedition to Indonesia in 1598. Walghe means \"tasteless\", \"insipid\", or \"sickly\", and voghel means \"bird\". The name was translated by Jakob Friedlib into German as Walchstök or Walchvögel. The original Dutch report titled Waarachtige Beschryving was lost, but the English translation survived:",
"title": "Taxonomy"
},
{
"paragraph_id": 11,
"text": "On their left hand was a little island which they named Heemskirk Island, and the bay it selve they called Warwick Bay... Here they taried 12. daies to refresh themselues, finding in this place great quantity of foules twice as bigge as swans, which they call Walghstocks or Wallowbirdes being very good meat. But finding an abundance of pigeons & popinnayes [parrots], they disdained any more to eat those great foules calling them Wallowbirds, that is to say lothsome or fulsome birdes.",
"title": "Taxonomy"
},
{
"paragraph_id": 12,
"text": "Another account from that voyage, perhaps the first to mention the dodo, states that the Portuguese referred to them as penguins. The meaning may not have been derived from penguin (the Portuguese referred to those birds as \"fotilicaios\" at the time), but from pinion, a reference to the small wings. The crew of the Dutch ship Gelderland referred to the bird as \"Dronte\" (meaning \"swollen\") in 1602, a name that is still used in some languages. This crew also called them \"griff-eendt\" and \"kermisgans\", in reference to fowl fattened for the Kermesse festival in Amsterdam, which was held the day after they anchored on Mauritius.",
"title": "Taxonomy"
},
{
"paragraph_id": 13,
"text": "The etymology of the word dodo is unclear. Some ascribe it to the Dutch word dodoor for \"sluggard\", but it is more probably related to Dodaars, which means either \"fat-arse\" or \"knot-arse\", referring to the knot of feathers on the hind end. The first record of the word Dodaars is in Captain Willem Van West-Zanen's journal in 1602. The English writer Sir Thomas Herbert was the first to use the word dodo in print in his 1634 travelogue claiming it was referred to as such by the Portuguese, who had visited Mauritius in 1507. Another Englishman, Emmanuel Altham, had used the word in a 1628 letter in which he also claimed its origin was Portuguese. The name \"dodar\" was introduced into English at the same time as dodo, but was only used until the 18th century. As far as is known, the Portuguese never mentioned the bird. Nevertheless, some sources still state that the word dodo derives from the Portuguese word doudo (currently doido), meaning \"fool\" or \"crazy\". It has also been suggested that dodo was an onomatopoeic approximation of the bird's call, a two-note pigeon-like sound resembling \"doo-doo\".",
"title": "Taxonomy"
},
{
"paragraph_id": 14,
"text": "The Latin name cucullatus (\"hooded\") was first used by Juan Eusebio Nieremberg in 1635 as Cygnus cucullatus, in reference to Carolus Clusius's 1605 depiction of a dodo. In his 18th-century classic work Systema Naturae, Carl Linnaeus used cucullatus as the specific name, but combined it with the genus name Struthio (ostrich). Mathurin Jacques Brisson coined the genus name Raphus (referring to the bustards) in 1760, resulting in the current name Raphus cucullatus. In 1766, Linnaeus coined the new binomial Didus ineptus (meaning \"inept dodo\"). This has become a synonym of the earlier name because of nomenclatural priority.",
"title": "Taxonomy"
},
{
"paragraph_id": 15,
"text": "As no complete dodo specimens exist, its external appearance, such as plumage and colouration, is hard to determine. Illustrations and written accounts of encounters with the dodo between its discovery and its extinction (1598–1662) are the primary evidence for its external appearance. According to most representations, the dodo had greyish or brownish plumage, with lighter primary feathers and a tuft of curly light feathers high on its rear end. The head was grey and naked, the beak green, black and yellow, and the legs were stout and yellowish, with black claws. A study of the few remaining feathers on the Oxford specimen head showed that they were pennaceous rather than plumaceous (downy) and most similar to those of other pigeons.",
"title": "Description"
},
{
"paragraph_id": 16,
"text": "Subfossil remains and remnants of the birds that were brought to Europe in the 17th century show that dodos were very large birds, measuring around 62.6–75 cm (2.05–2.46 ft) in height. The bird was sexually dimorphic; males were larger and had proportionally longer beaks. Weight estimates have varied from study to study. In 1993, Bradley C. Livezey proposed that males would have weighed 21 kilograms (46 lb) and females 17 kilograms (37 lb). Also in 1993, Andrew C. Kitchener attributed a high contemporary weight estimate and the roundness of dodos depicted in Europe to these birds having been overfed in captivity; weights in the wild were estimated to have been in the range of 10.6–17.5 kg (23–39 lb), and fattened birds could have weighed 21.7–27.8 kg (48–61 lb). A 2011 estimate by Angst and colleagues gave an average weight as low as 10.2 kg (22 lb). This has also been questioned, and there is still controversy over weight estimates. A 2016 study estimated the weight at 10.6 to 14.3 kg (23 to 32 lb), based on CT scans of composite skeletons. It has also been suggested that the weight depended on the season, and that individuals were fat during cool seasons, but less so during hot.",
"title": "Description"
},
{
"paragraph_id": 17,
"text": "The skull of the dodo differed much from those of other pigeons, especially in being more robust, the bill having a hooked tip, and in having a short cranium compared to the jaws. The upper bill was nearly twice as long as the cranium, which was short compared to those of its closest pigeon relatives. The openings of the bony nostrils were elongated along the length of the beak, and they contained no bony septum. The cranium (excluding the beak) was wider than it was long, and the frontal bone formed a dome-shape, with the highest point above the hind part of the eye sockets. The skull sloped downwards at the back. The eye sockets occupied much of the hind part of the skull. The sclerotic rings inside the eye were formed by eleven ossicles (small bones), similar to the amount in other pigeons. The mandible was slightly curved, and each half had a single fenestra (opening), as in other pigeons.",
"title": "Description"
},
{
"paragraph_id": 18,
"text": "The dodo had about nineteen presynsacral vertebrae (those of the neck and thorax, including three fused into a notarium), sixteen synsacral vertebrae (those of the lumbar region and sacrum), six free tail (caudal) vertebrae, and a pygostyle. The neck had well-developed areas for muscle and ligament attachment, probably to support the heavy skull and beak. On each side, it had six ribs, four of which articulated with the sternum through sternal ribs. The sternum was large, but small in relation to the body compared to those of much smaller pigeons that are able to fly. The sternum was highly pneumatic, broad, and relatively thick in cross-section. The bones of the pectoral girdle, shoulder blades, and wing bones were reduced in size compared to those of flighted pigeon, and were more gracile compared to those of the Rodrigues solitaire, but none of the individual skeletal components had disappeared. The carpometacarpus of the dodo was more robust than that of the solitaire, however. The pelvis was wider than that of the solitaire and other relatives, yet was comparable to the proportions in some smaller, flighted pigeons. Most of the leg bones were more robust than those of extant pigeons and the solitaire, but the length proportions were little different.",
"title": "Description"
},
{
"paragraph_id": 19,
"text": "Many of the skeletal features that distinguish the dodo and the Rodrigues solitaire, its closest relative, from other pigeons have been attributed to their flightlessness. The pelvic elements were thicker than those of flighted pigeons to support the higher weight, and the pectoral region and the small wings were paedomorphic, meaning that they were underdeveloped and retained juvenile features. The skull, trunk and pelvic limbs were peramorphic, meaning that they changed considerably with age. The dodo shared several other traits with the Rodrigues solitaire, such as features of the skull, pelvis, and sternum, as well as their large size. It differed in other aspects, such as being more robust and shorter than the solitaire, having a larger skull and beak, a rounded skull roof, and smaller orbits. The dodo's neck and legs were proportionally shorter, and it did not possess an equivalent to the knob present on the solitaire's wrists.",
"title": "Description"
},
{
"paragraph_id": 20,
"text": "Most contemporary descriptions of the dodo are found in ship's logs and journals of the Dutch East India Company vessels that docked in Mauritius when the Dutch Empire ruled the island. These records were used as guides for future voyages. Few contemporary accounts are reliable, as many seem to be based on earlier accounts, and none were written by scientists. One of the earliest accounts, from van Warwijck's 1598 journal, describes the bird as follows:",
"title": "Description"
},
{
"paragraph_id": 21,
"text": "Blue parrots are very numerous there, as well as other birds; among which are a kind, conspicuous for their size, larger than our swans, with huge heads only half covered with skin as if clothed with a hood. These birds lack wings, in the place of which 3 or 4 blackish feathers protrude. The tail consists of a few soft incurved feathers, which are ash coloured. These we used to call 'Walghvogel', for the reason that the longer and oftener they were cooked, the less soft and more insipid eating they became. Nevertheless their belly and breast were of a pleasant flavour and easily masticated.",
"title": "Description"
},
{
"paragraph_id": 22,
"text": "One of the most detailed descriptions is by Herbert in A Relation of Some Yeares Travaille into Afrique and the Greater Asia from 1634:",
"title": "Description"
},
{
"paragraph_id": 23,
"text": "First here only and in Dygarrois [Rodrigues] is generated the Dodo, which for shape and rareness may antagonize the Phoenix of Arabia: her body is round and fat, few weigh less than fifty pound. It is reputed more for wonder than for food, greasie stomackes may seeke after them, but to the delicate they are offensive and of no nourishment. Her visage darts forth melancholy, as sensible of Nature's injurie in framing so great a body to be guided with complementall wings, so small and impotent, that they serve only to prove her bird. The halfe of her head is naked seeming couered with a fine vaile, her bill is crooked downwards, in midst is the thrill [nostril], from which part to the end tis a light green, mixed with pale yellow tincture; her eyes are small and like to Diamonds, round and rowling; her clothing downy feathers, her train three small plumes, short and inproportionable, her legs suiting her body, her pounces sharpe, her appetite strong and greedy. Stones and iron are digested, which description will better be conceived in her representation.",
"title": "Description"
},
{
"paragraph_id": 24,
"text": "The travel journal of the Dutch ship Gelderland (1601–1603), rediscovered in the 1860s, contains the only known sketches of living or recently killed specimens drawn on Mauritius. They have been attributed to the professional artist Joris Joostensz Laerle, who also drew other now-extinct Mauritian birds, and to a second, less refined artist. Apart from these sketches, it is unknown how many of the twenty or so 17th-century illustrations of the dodos were drawn from life or from stuffed specimens, which affects their reliability. Since dodos are otherwise only known from limited physical remains and descriptions, contemporary artworks are important to reconstruct their appearance in life. While there has been an effort since the mid-19 century to list all historical illustrations of dodos, previously unknown depictions continue to be discovered occasionally.",
"title": "Description"
},
{
"paragraph_id": 25,
"text": "The traditional image of the dodo is of a very fat and clumsy bird, but this view may be exaggerated. The general opinion of scientists today is that many old European depictions were based on overfed captive birds or crudely stuffed specimens. It has also been suggested that the images might show dodos with puffed feathers, as part of display behaviour. The Dutch painter Roelant Savery was the most prolific and influential illustrator of the dodo, having made at least twelve depictions, often showing it in the lower corners. A famous painting of his from 1626, now called Edwards's Dodo as it was once owned by the ornithologist George Edwards, has since become the standard image of a dodo. It is housed in the Natural History Museum, London. The image shows a particularly fat bird and is the source for many other dodo illustrations.",
"title": "Description"
},
{
"paragraph_id": 26,
"text": "An Indian Mughal painting rediscovered in the Hermitage Museum, St. Petersburg, in 1955 shows a dodo along with native Indian birds. It depicts a slimmer, brownish bird, and its discoverer Aleksander Iwanow and British palaeontologist Julian Hume regarded it as one of the most accurate depictions of the living dodo; the surrounding birds are clearly identifiable and depicted with appropriate colouring. It is believed to be from the 17th century and has been attributed to the Mughal painter Ustad Mansur. The bird depicted probably lived in the menagerie of the Mughal Emperor Jahangir, located in Surat, where the English traveller Peter Mundy also claimed to have seen two dodos sometime between 1628 and 1633. In 2014, another Indian illustration of a dodo was reported, but it was found to be derivative of an 1836 German illustration.",
"title": "Description"
},
{
"paragraph_id": 27,
"text": "All post-1638 depictions appear to be based on earlier images, around the time reports mentioning dodos became rarer. Differences in the depictions led ornithologists such as Anthonie Cornelis Oudemans and Masauji Hachisuka to speculate about sexual dimorphism, ontogenic traits, seasonal variation, and even the existence of different species, but these theories are not accepted today. Because details such as markings of the beak, the form of the tail feathers, and colouration vary from account to account, it is impossible to determine the exact morphology of these features, whether they signal age or sex, or if they even reflect reality. Hume argued that the nostrils of the living dodo would have been slits, as seen in the Gelderland, Cornelis Saftleven, Savery's Crocker Art Gallery, and Mansur images. According to this claim, the gaping nostrils often seen in paintings indicate that taxidermy specimens were used as models. Most depictions show that the wings were held in an extended position, unlike flighted pigeons, but similar to ratites such as the ostrich and kiwi.",
"title": "Description"
},
{
"paragraph_id": 28,
"text": "Little is known of the behaviour of the dodo, as most contemporary descriptions are very brief. Based on weight estimates, it has been suggested the male could reach the age of 21, and the female 17. Studies of the cantilever strength of its leg bones indicate that it could run quite fast. The legs were robust and strong to support the bulk of the bird, and also made it agile and manoeuvrable in the dense, pre-human landscape. Though the wings were small, well-developed muscle scars on the bones show that they were not completely vestigial, and may have been used for display behaviour and balance; extant pigeons also use their wings for such purposes. Unlike the Rodrigues solitaire, there is no evidence that the dodo used its wings in intraspecific combat. Though some dodo bones have been found with healed fractures, it had weak pectoral muscles and more reduced wings in comparison. The dodo may instead have used its large, hooked beak in territorial disputes. Since Mauritius receives more rainfall and has less seasonal variation than Rodrigues, which would have affected the availability of resources on the island, the dodo would have less reason to evolve aggressive territorial behaviour. The Rodrigues solitaire was therefore probably the more aggressive of the two. In 2016, the first 3D endocast was made from the brain of the dodo; the brain-to-body-size ratio was similar to that of modern pigeons, indicating that dodos were probably equal in intelligence.",
"title": "Behaviour and ecology"
},
{
"paragraph_id": 29,
"text": "The preferred habitat of the dodo is unknown, but old descriptions suggest that it inhabited the woods on the drier coastal areas of south and west Mauritius. This view is supported by the fact that the Mare aux Songes swamp, where most dodo remains have been excavated, is close to the sea in south-eastern Mauritius. Such a limited distribution across the island could well have contributed to its extinction. A 1601 map from the Gelderland journal shows a small island off the coast of Mauritius where dodos were caught. Julian Hume has suggested this island was l'île aux Benitiers in Tamarin Bay, on the west coast of Mauritius. Subfossil bones have also been found inside caves in highland areas, indicating that it once occurred on mountains. Work at the Mare aux Songes swamp has shown that its habitat was dominated by tambalacoque and Pandanus trees and endemic palms. The near-coastal placement and wetness of the Mare aux Songes led to a high diversity of plant species, whereas the surrounding areas were drier.",
"title": "Behaviour and ecology"
},
{
"paragraph_id": 30,
"text": "Many endemic species of Mauritius became extinct after the arrival of humans, so the ecosystem of the island is badly damaged and hard to reconstruct. Before humans arrived, Mauritius was entirely covered in forests, but very little remains of them today, because of deforestation. The surviving endemic fauna is still seriously threatened. The dodo lived alongside other recently extinct Mauritian birds such as the flightless red rail, the broad-billed parrot, the Mascarene grey parakeet, the Mauritius blue pigeon, the Mauritius scops owl, the Mascarene coot, the Mauritian shelduck, the Mauritian duck, and the Mauritius night heron. Extinct Mauritian reptiles include the saddle-backed Mauritius giant tortoise, the domed Mauritius giant tortoise, the Mauritian giant skink, and the Round Island burrowing boa. The small Mauritian flying fox and the snail Tropidophora carinata lived on Mauritius and Réunion, but vanished from both islands. Some plants, such as Casearia tinifolia and the palm orchid, have also become extinct.",
"title": "Behaviour and ecology"
},
{
"paragraph_id": 31,
"text": "A 1631 Dutch letter (long thought lost, but rediscovered in 2017) is the only account of the dodo's diet, and also mentions that it used its beak for defence. The document uses word-play to refer to the animals described, with dodos presumably being an allegory for wealthy mayors:",
"title": "Behaviour and ecology"
},
{
"paragraph_id": 32,
"text": "The mayors are superb and proud. They presented themselves with an unyielding, stern face and wide open mouth, very jaunty and audacious of gait. They did not want to budge before us; their war weapon was the mouth, with which they could bite fiercely. Their food was raw fruit; they were not dressed very well, but were rich and fat, therefore we brought many of them on board, to the contentment of us all.",
"title": "Behaviour and ecology"
},
{
"paragraph_id": 33,
"text": "In addition to fallen fruits, the dodo probably subsisted on nuts, seeds, bulbs, and roots. It has also been suggested that the dodo might have eaten crabs and shellfish, like their relatives the crowned pigeons. Its feeding habits must have been versatile, since captive specimens were probably given a wide range of food on the long sea journeys. Oudemans suggested that as Mauritius has marked dry and wet seasons, the dodo probably fattened itself on ripe fruits at the end of the wet season to survive the dry season, when food was scarce; contemporary reports describe the bird's \"greedy\" appetite. The Mauritian ornithologist France Staub suggested in 1996 that they mainly fed on palm fruits, and he attempted to correlate the fat-cycle of the dodo with the fruiting regime of the palms.",
"title": "Behaviour and ecology"
},
{
"paragraph_id": 34,
"text": "Skeletal elements of the upper jaw appear to have been rhynchokinetic (movable in relation to each other), which must have affected its feeding behaviour. In extant birds, such as frugivorous (fruit-eating) pigeons, kinetic premaxillae help with consuming large food items. The beak also appears to have been able to withstand high force loads, which indicates a diet of hard food. Examination of the brain endocast found that though the brain was similar to that of other pigeons in most respects, the dodo had a comparatively large olfactory bulb. This gave the dodo a good sense of smell, which may have aided in locating fruit and small prey.",
"title": "Behaviour and ecology"
},
{
"paragraph_id": 35,
"text": "Several contemporary sources state that the dodo used Gastroliths (gizzard stones) to aid digestion. The English writer Sir Hamon L'Estrange witnessed a live bird in London and described it as follows:",
"title": "Behaviour and ecology"
},
{
"paragraph_id": 36,
"text": "About 1638, as I walked London streets, I saw the picture of a strange looking fowle hung out upon a clothe and myselfe with one or two more in company went in to see it. It was kept in a chamber, and was a great fowle somewhat bigger than the largest Turkey cock, and so legged and footed, but stouter and thicker and of more erect shape, coloured before like the breast of a young cock fesan, and on the back of a dunn or dearc colour. The keeper called it a Dodo, and in the ende of a chymney in the chamber there lay a heape of large pebble stones, whereof hee gave it many in our sight, some as big as nutmegs, and the keeper told us that she eats them (conducing to digestion), and though I remember not how far the keeper was questioned therein, yet I am confident that afterwards she cast them all again.",
"title": "Behaviour and ecology"
},
{
"paragraph_id": 37,
"text": "It is not known how the young were fed, but related pigeons provide crop milk. Contemporary depictions show a large crop, which was probably used to add space for food storage and to produce crop milk. It has been suggested that the maximum size attained by the dodo and the solitaire was limited by the amount of crop milk they could produce for their young during early growth.",
"title": "Behaviour and ecology"
},
{
"paragraph_id": 38,
"text": "In 1973, the tambalacoque, also known as the dodo tree, was thought to be dying out on Mauritius, to which it is endemic. There were supposedly only 13 specimens left, all estimated to be about 300 years old. Stanley Temple hypothesised that it depended on the dodo for its propagation, and that its seeds would germinate only after passing through the bird's digestive tract. He claimed that the tambalacoque was now nearly coextinct because of the disappearance of the dodo. Temple overlooked reports from the 1940s that found that tambalacoque seeds germinated, albeit very rarely, without being abraded during digestion. Others have contested his hypothesis and suggested that the decline of the tree was exaggerated or seeds were also distributed by other extinct animals such as Cylindraspis tortoises, fruit bats, or the broad-billed parrot. According to Wendy Strahm and Anthony Cheke, two experts in the ecology of the Mascarene Islands, the tree, while rare, has germinated since the demise of the dodo and numbers several hundred, not 13 as claimed by Temple, hence, discrediting Temple's view as to the dodo and the tree's sole survival relationship.",
"title": "Behaviour and ecology"
},
{
"paragraph_id": 39,
"text": "The Brazilian ornithologist Carlos Yamashita suggested in 1997 that the broad-billed parrot may have depended on dodos and Cylindraspis tortoises to eat palm fruits and excrete their seeds, which became food for the parrots. Anodorhynchus macaws depended on now-extinct South American megafauna in the same way, but now rely on domesticated cattle for this service.",
"title": "Behaviour and ecology"
},
{
"paragraph_id": 40,
"text": "As it was flightless and terrestrial and there were no mammalian predators or other kinds of natural enemy on Mauritius, the dodo probably nested on the ground. The account by François Cauche from 1651 is the only description of the egg and the call:",
"title": "Behaviour and ecology"
},
{
"paragraph_id": 41,
"text": "I have seen in Mauritius birds bigger than a Swan, without feathers on the body, which is covered with a black down; the hinder part is round, the rump adorned with curled feathers as many in number as the bird is years old. In place of wings they have feathers like these last, black and curved, without webs. They have no tongues, the beak is large, curving a little downwards; their legs are long, scaly, with only three toes on each foot. It has a cry like a gosling, and is by no means so savoury to eat as the Flamingos and Ducks of which we have just spoken. They only lay one egg which is white, the size of a halfpenny roll, by the side of which they place a white stone the size of a hen's egg. They lay on grass which they collect, and make their nests in the forests; if one kills the young one, a grey stone is found in the gizzard. We call them Oiseaux de Nazaret. The fat is excellent to give ease to the muscles and nerves.",
"title": "Behaviour and ecology"
},
{
"paragraph_id": 42,
"text": "Cauche's account is problematic, since it also mentions that the bird he was describing had three toes and no tongue, unlike dodos. This led some to believe that Cauche was describing a new species of dodo (\"Didus nazarenus\"). The description was most probably mingled with that of a cassowary, and Cauche's writings have other inconsistencies. A mention of a \"young ostrich\" taken on board a ship in 1617 is the only other reference to a possible juvenile dodo. An egg claimed to be that of a dodo is stored in the East London Museum in South Africa. It was donated by the South African museum official Marjorie Courtenay-Latimer, whose great aunt had received it from a captain who claimed to have found it in a swamp on Mauritius. In 2010, the curator of the museum proposed using genetic studies to determine its authenticity. It may instead be an aberrant ostrich egg.",
"title": "Behaviour and ecology"
},
{
"paragraph_id": 43,
"text": "Because of the possible single-egg clutch and the bird's large size, it has been proposed that the dodo was K-selected, meaning that it produced few altricial offspring, which required parental care until they matured. Some evidence, including the large size and the fact that tropical and frugivorous birds have slower growth rates, indicates that the bird may have had a protracted development period. The fact that no juvenile dodos have been found in the Mare aux Songes swamp may indicate that they produced little offspring, that they matured rapidly, that the breeding grounds were far away from the swamp, or that the risk of miring was seasonal.",
"title": "Behaviour and ecology"
},
{
"paragraph_id": 44,
"text": "A 2017 study examined the histology of thin-sectioned dodo bones, modern Mauritian birds, local ecology, and contemporary accounts, to recover information about the life history of the dodo. The study suggested that dodos bred around August, after having potentially fattened themselves, corresponding with the fat and thin cycles of many vertebrates of Mauritius. The chicks grew rapidly, reaching robust, almost adult, sizes, and sexual maturity before Austral summer or the cyclone season. Adult dodos which had just bred moulted after Austral summer, around March. The feathers of the wings and tail were replaced first, and the moulting would have completed at the end of July, in time for the next breeding season. Different stages of moulting may also account for inconsistencies in contemporary descriptions of dodo plumage.",
"title": "Behaviour and ecology"
},
{
"paragraph_id": 45,
"text": "Mauritius had previously been visited by Arab vessels in the Middle Ages and Portuguese ships between 1507 and 1513, but was settled by neither. No records of dodos by these are known, although the Portuguese name for Mauritius, \"Cerne (swan) Island\", may have been a reference to dodos. The Dutch Empire acquired Mauritius in 1598, renaming it after Maurice of Nassau, and it was used for the provisioning of trade vessels of the Dutch East India Company henceforward. The earliest known accounts of the dodo were provided by Dutch travellers during the Second Dutch Expedition to Indonesia, led by admiral Jacob van Neck in 1598. They appear in reports published in 1601, which also contain the first published illustration of the bird. Since the first sailors to visit Mauritius had been at sea for a long time, their interest in these large birds was mainly culinary. The 1602 journal by Willem Van West-Zanen of the ship Bruin-Vis mentions that 24–25 dodos were hunted for food, which were so large that two could scarcely be consumed at mealtime, their remains being preserved by salting. An illustration made for the 1648 published version of this journal, showing the killing of dodos, a dugong, and possibly Mascarene grey parakeets, was captioned with a Dutch poem, here in Hugh Strickland's 1848 translation:",
"title": "Relationship with humans"
},
{
"paragraph_id": 46,
"text": "For food the seamen hunt the flesh of feathered fowl, They tap the palms, and round-rumped dodos they destroy, The parrot's life they spare that he may peep and howl, And thus his fellows to imprisonment decoy.",
"title": "Relationship with humans"
},
{
"paragraph_id": 47,
"text": "Some early travellers found dodo meat unsavoury, and preferred to eat parrots and pigeons; others described it as tough, but good. Some hunted dodos only for their gizzards, as this was considered the most delicious part of the bird. Dodos were easy to catch, but hunters had to be careful not to be bitten by their powerful beaks.",
"title": "Relationship with humans"
},
{
"paragraph_id": 48,
"text": "The appearance of the dodo and the red rail led Peter Mundy to speculate, 230 years before Charles Darwin's theory of evolution:",
"title": "Relationship with humans"
},
{
"paragraph_id": 49,
"text": "Of these 2 sorts off fowl afforementionede, For oughtt wee yett know, Not any to bee Found out of this Iland, which lyeth aboutt 100 leagues From St. Lawrence. A question may bee demaunded how they should bee here and Not elcewhere, beeing soe Farer From other land and can Neither fly or swymme; whither by Mixture off kindes producing straunge and Monstrous formes, or the Nature of the Climate, ayer and earth in alltring the First shapes in long tyme, or how.",
"title": "Relationship with humans"
},
{
"paragraph_id": 50,
"text": "The dodo was found interesting enough that living specimens were sent to Europe and the East. The number of transported dodos that reached their destinations alive is uncertain, and it is unknown how they relate to contemporary depictions and the few non-fossil remains in European museums. Based on a combination of contemporary accounts, paintings, and specimens, Julian Hume has inferred that at least eleven transported dodos reached their destinations alive.",
"title": "Relationship with humans"
},
{
"paragraph_id": 51,
"text": "Hamon L'Estrange's description of a dodo that he saw in London in 1638 is the only account that specifically mentions a live specimen in Europe. In 1626 Adriaen van de Venne drew a dodo that he claimed to have seen in Amsterdam, but he did not mention if it was alive, and his depiction is reminiscent of Savery's Edwards's Dodo. Two live specimens were seen by Peter Mundy in Surat, India, between 1628 and 1634, one of which may have been the individual painted by Mansur around 1625. In 1628, Emmanuel Altham visited Mauritius and sent a letter to his brother in England:",
"title": "Relationship with humans"
},
{
"paragraph_id": 52,
"text": "Right wo and lovinge brother, we were ordered by ye said councell to go to an island called Mauritius, lying in 20d. of south latt., where we arrived ye 28th of May; this island having many goates, hogs and cowes upon it, and very strange fowles, called by ye portingalls Dodo, which for the rareness of the same, the like being not in ye world but here, I have sent you one by Mr. Perce, who did arrive with the ship William at this island ye 10th of June. [In the margin of the letter] Of Mr. Perce you shall receive a jarr of ginger for my sister, some beades for my cousins your daughters, and a bird called a Dodo, if it live.",
"title": "Relationship with humans"
},
{
"paragraph_id": 53,
"text": "Whether the dodo survived the journey is unknown, and the letter was destroyed by fire in the 19th century. The earliest known picture of a dodo specimen in Europe is from a c. 1610 collection of paintings depicting animals in the royal menagerie of Emperor Rudolph II in Prague. This collection includes paintings of other Mauritian animals as well, including a red rail. The dodo, which may be a juvenile, seems to have been dried or embalmed, and had probably lived in the emperor's zoo for a while together with the other animals. That whole stuffed dodos were present in Europe indicates they had been brought alive and died there; it is unlikely that taxidermists were on board the visiting ships, and spirits were not yet used to preserve biological specimens. Most tropical specimens were preserved as dried heads and feet.",
"title": "Relationship with humans"
},
{
"paragraph_id": 54,
"text": "One dodo was reportedly sent as far as Nagasaki, Japan, in 1647, but it was long unknown whether it arrived. Contemporary documents first published in 2014 proved the story, and showed that it had arrived alive. It was meant as a gift, and, despite its rarity, was considered of equal value to a white deer and a bezoar stone. It is the last recorded live dodo in captivity.",
"title": "Relationship with humans"
},
{
"paragraph_id": 55,
"text": "Like many animals that evolved in isolation from significant predators, the dodo was entirely fearless of humans. This fearlessness and its inability to fly made the dodo easy prey for sailors. Although some scattered reports describe mass killings of dodos for ships' provisions, archaeological investigations have found scant evidence of human predation. Bones of at least two dodos were found in caves at Baie du Cap that sheltered fugitive slaves and convicts in the 17th century, which would not have been easily accessible to dodos because of the high, broken terrain. The human population on Mauritius (an area of 1,860 km or 720 sq mi) never exceeded 50 people in the 17th century, but they introduced other animals, including dogs, pigs, cats, rats, and crab-eating macaques, which plundered dodo nests and competed for the limited food resources. At the same time, humans destroyed the forest habitat of the dodos. The impact of the introduced animals on the dodo population, especially the pigs and macaques, is today considered more severe than that of hunting. Rats were perhaps not much of a threat to the nests, since dodos would have been used to dealing with local land crabs.",
"title": "Relationship with humans"
},
{
"paragraph_id": 56,
"text": "It has been suggested that the dodo may already have been rare or localised before the arrival of humans on Mauritius, since it would have been unlikely to become extinct so rapidly if it had occupied all the remote areas of the island. A 2005 expedition found subfossil remains of dodos and other animals killed by a flash flood. Such mass mortalities would have further jeopardised a species already in danger of becoming extinct. Yet the fact that the dodo survived hundreds of years of volcanic activity and climatic changes shows the bird was resilient within its ecosystem.",
"title": "Relationship with humans"
},
{
"paragraph_id": 57,
"text": "Some controversy surrounds the date of its extinction. The last widely accepted record of a dodo sighting is the 1662 report by shipwrecked mariner Volkert Evertsz of the Dutch ship Arnhem, who described birds caught on a small islet off Mauritius, now suggested to be Amber Island:",
"title": "Relationship with humans"
},
{
"paragraph_id": 58,
"text": "These animals on our coming up to them stared at us and remained quiet where they stand, not knowing whether they had wings to fly away or legs to run off, and suffering us to approach them as close as we pleased. Amongst these birds were those which in India they call Dod-aersen (being a kind of very big goose); these birds are unable to fly, and instead of wings, they merely have a few small pins, yet they can run very swiftly. We drove them together into one place in such a manner that we could catch them with our hands, and when we held one of them by its leg, and that upon this it made a great noise, the others all on a sudden came running as fast as they could to its assistance, and by which they were caught and made prisoners also.",
"title": "Relationship with humans"
},
{
"paragraph_id": 59,
"text": "The dodos on this islet may not necessarily have been the last members of the species. The last claimed sighting of a dodo was reported in the hunting records of Isaac Johannes Lamotius in 1688. A 2003 statistical analysis of these records by the biologists David L. Roberts and Andrew R. Solow gave a new estimated extinction date of 1693, with a 95% confidence interval of 1688–1715. These authors also pointed out that because the last sighting before 1662 was in 1638, the dodo was probably already quite rare by the 1660s, and thus a disputed report from 1674 by an escaped slave could not be dismissed out of hand.",
"title": "Relationship with humans"
},
{
"paragraph_id": 60,
"text": "The British ornithologist Alfred Newton suggested in 1868 that the name of the dodo was transferred to the red rail after the former had gone extinct. Cheke also pointed out that some descriptions after 1662 use the names \"Dodo\" and \"Dodaers\" when referring to the red rail, indicating that they had been transferred to it. He therefore pointed to the 1662 description as the last credible observation. A 1668 account by English traveller John Marshall, who used the names \"Dodo\" and \"Red Hen\" interchangeably for the red rail, mentioned that the meat was \"hard\", which echoes the description of the meat in the 1681 account. Even the 1662 account has been questioned by the writer Errol Fuller, as the reaction to distress cries matches what was described for the red rail. Until this explanation was proposed, a description of \"dodos\" from 1681 was thought to be the last account, and that date still has proponents.",
"title": "Relationship with humans"
},
{
"paragraph_id": 61,
"text": "Cheke stated in 2014 that then recently accessible Dutch manuscripts indicate that no dodos were seen by settlers in 1664–1674. In 2020, Cheke and the British researcher Jolyon C. Parish suggested that all mentions of dodos after the mid-17th century instead referred to red rails, and that the dodo had disappeared due to predation by feral pigs during a hiatus in settlement of Mauritius (1658–1664). The dodo's extinction therefore was not realised at the time, since new settlers had not seen real dodos, but as they expected to see flightless birds, they referred to the red rail by that name instead. Since red rails probably had larger clutches than dodos and their eggs could be incubated faster, and their nests were perhaps concealed, they probably bred more efficiently, and were less vulnerable to pigs.",
"title": "Relationship with humans"
},
{
"paragraph_id": 62,
"text": "It is unlikely the issue will ever be resolved, unless late reports mentioning the name alongside a physical description are rediscovered. The IUCN Red List accepts Cheke's rationale for choosing the 1662 date, taking all subsequent reports to refer to red rails. In any case, the dodo was probably extinct by 1700, about a century after its discovery in 1598. The Dutch left Mauritius in 1710, but by then the dodo and most of the large terrestrial vertebrates there had become extinct.",
"title": "Relationship with humans"
},
{
"paragraph_id": 63,
"text": "Even though the rareness of the dodo was reported already in the 17th century, its extinction was not recognised until the 19th century. This was partly because, for religious reasons, extinction was not believed possible until later proved so by Georges Cuvier, and partly because many scientists doubted that the dodo had ever existed. It seemed altogether too strange a creature, and many believed it a myth. The bird was first used as an example of human-induced extinction in Penny Magazine in 1833, and has since been referred to as an \"icon\" of extinction.",
"title": "Relationship with humans"
},
{
"paragraph_id": 64,
"text": "The only extant remains of dodos taken to Europe in the 17th century are a dried head and foot in the Oxford University Museum of Natural History, a foot once housed in the British Museum but now lost, a skull in the University of Copenhagen Zoological Museum, and an upper jaw in the National Museum, Prague. The last two were rediscovered and identified as dodo remains in the mid-19th century. Several stuffed dodos were also mentioned in old museum inventories, but none are known to have survived. Apart from these remains, a dried foot, which belonged to the Dutch professor Pieter Pauw, was mentioned by Carolus Clusius in 1605. Its provenance is unknown, and it is now lost, but it may have been collected during the Van Neck voyage. Supposed stuffed dodos seen in museums around the world today have in fact been made from feathers of other birds, many of the older ones by the British taxidermist Rowland Ward's company.",
"title": "Physical remains"
},
{
"paragraph_id": 65,
"text": "The only known soft tissue remains, the Oxford head (specimen OUM 11605) and foot, belonged to the last known stuffed dodo, which was first mentioned as part of the Tradescant collection in 1656 and was moved to the Ashmolean Museum in 1659. It has been suggested that this might be the remains of the bird that Hamon L'Estrange saw in London, the bird sent by Emanuel Altham, or a donation by Thomas Herbert. Since the remains do not show signs of having been mounted, the specimen might instead have been preserved as a study skin. In 2018, it was reported that scans of the Oxford dodo's head showed that its skin and bone contained lead shot, pellets which were used to hunt birds in the 17th century. This indicates that the Oxford dodo was shot either before being transported to Britain, or some time after arriving. The circumstances of its killing are unknown, and the pellets are to be examined to identify where the lead was mined from.",
"title": "Physical remains"
},
{
"paragraph_id": 66,
"text": "Many sources state that the Ashmolean Museum burned the stuffed dodo around 1755 because of severe decay, saving only the head and leg. Statute 8 of the museum states \"That as any particular grows old and perishing the keeper may remove it into one of the closets or other repository; and some other to be substituted.\" The deliberate destruction of the specimen is now believed to be a myth; it was removed from exhibition to preserve what remained of it. This remaining soft tissue has since degraded further; the head was dissected by Strickland and Melville, separating the skin from the skull in two-halves. The foot is in a skeletal state, with only scraps of skin and tendons. Very few feathers remain on the head. It is probably a female, as the foot is 11% smaller and more gracile than the London foot, yet appears to be fully grown. The specimen was exhibited at the Oxford museum from at least the 1860s and until 1998, where-after it was mainly kept in storage to prevent damage. Casts of the head can today be found in many museums worldwide.",
"title": "Physical remains"
},
{
"paragraph_id": 67,
"text": "The dried London foot, first mentioned in 1665, and transferred to the British Museum in the 18th century, was displayed next to Savery's Edwards's Dodo painting until the 1840s, and it too was dissected by Strickland and Melville. It was not posed in a standing posture, which suggests that it was severed from a fresh specimen, not a mounted one. By 1896 it was mentioned as being without its integuments, and only the bones are believed to remain today, though its present whereabouts are unknown.",
"title": "Physical remains"
},
{
"paragraph_id": 68,
"text": "The Copenhagen skull (specimen ZMUC 90-806) is known to have been part of the collection of Bernardus Paludanus in Enkhuizen until 1651, when it was moved to the museum in Gottorf Castle, Schleswig. After the castle was occupied by Danish forces in 1702, the museum collection was assimilated into the Royal Danish collection. The skull was rediscovered by J. T. Reinhardt in 1840. Based on its history, it may be the oldest known surviving remains of a dodo brought to Europe in the 17th century. It is 13 mm (0.51 in) shorter than the Oxford skull, and may have belonged to a female. It was mummified, but the skin has perished.",
"title": "Physical remains"
},
{
"paragraph_id": 69,
"text": "The front part of a skull (specimen NMP P6V-004389) in the National Museum of Prague was found in 1850 among the remains of the Böhmisches Museum. Other elements supposedly belonging to this specimen have been listed in the literature, but it appears only the partial skull was ever present (a partial right limb in the museum appears to be from a Rodrigues solitaire). It may be what remains of one of the stuffed dodos known to have been at the menagerie of Emperor Rudolph II, possibly the specimen painted by Hoefnagel or Savery there.",
"title": "Physical remains"
},
{
"paragraph_id": 70,
"text": "Until 1860, the only known dodo remains were the four incomplete 17th-century specimens. Philip Burnard Ayres found the first subfossil bones in 1860, which were sent to Richard Owen at the British Museum, who did not publish the findings. In 1863, Owen requested the Mauritian Bishop Vincent Ryan to spread word that he should be informed if any dodo bones were found. In 1865, George Clark, the government schoolmaster at Mahébourg, finally found an abundance of subfossil dodo bones in the swamp of Mare aux Songes in Southern Mauritius, after a 30-year search inspired by Strickland and Melville's monograph. In 1866, Clark explained his procedure to The Ibis, an ornithology journal: he had sent his coolies to wade through the centre of the swamp, feeling for bones with their feet. At first they found few bones, until they cut away herbage that covered the deepest part of the swamp, where they found many fossils. Harry Pasley Higginson, a railway engineer from Yorkshire, reports discovering the Mare aux Songes bones at the same time as Clark and there is some dispute over who found them first. Higginson sent boxes of these bones to Liverpool, Leeds and York museums. The swamp yielded the remains of over 300 dodos, but very few skull and wing bones, possibly because the upper bodies were washed away or scavenged while the lower body was trapped. The situation is similar to many finds of moa remains in New Zealand marshes. Most dodo remains from the Mare aux Songes have a medium to dark brown colouration.",
"title": "Physical remains"
},
{
"paragraph_id": 71,
"text": "Clark's reports about the finds rekindled interest in the bird. Sir Richard Owen and Alfred Newton both wanted to be first to describe the post-cranial anatomy of the dodo, and Owen bought a shipment of dodo bones originally meant for Newton, which led to rivalry between the two. Owen described the bones in Memoir on the Dodo in October 1866, but erroneously based his reconstruction on the Edwards's Dodo painting by Savery, making it too squat and obese. In 1869 he received more bones and corrected its stance, making it more upright. Newton moved his focus to the Réunion solitaire instead. The remaining bones not sold to Owen or Newton were auctioned off or donated to museums. In 1889, Théodor Sauzier was commissioned to explore the \"historical souvenirs\" of Mauritius and find more dodo remains in the Mare aux Songes. He was successful, and also found remains of other extinct species.",
"title": "Physical remains"
},
{
"paragraph_id": 72,
"text": "In 2005, after a hundred years of neglect, a part of the Mare aux Songes swamp was excavated by an international team of researchers (International Dodo Research Project). To prevent malaria, the British had covered the swamp with hard core during their rule over Mauritius, which had to be removed. Many remains were found, including bones of at least 17 dodos in various stages of maturity (though no juveniles), and several bones obviously from the skeleton of one individual bird, which have been preserved in their natural position. These findings were made public in December 2005 in the Naturalis museum in Leiden. 63% of the fossils found in the swamp belonged to turtles of the extinct genus Cylindraspis, and 7.1% belonged to dodos, which had been deposited within several centuries, 4,000 years ago. Subsequent excavations suggested that dodos and other animals became mired in the Mare aux Songes while trying to reach water during a long period of severe drought about 4,200 years ago. Furthermore, cyanobacteria thrived in the conditions created by the excrements of animals gathered around the swamp, which died of intoxication, dehydration, trampling, and miring. Though many small skeletal elements were found during the recent excavations of the swamp, few were found during the 19th century, probably owing to the employment of less refined methods when collecting.",
"title": "Physical remains"
},
{
"paragraph_id": 73,
"text": "Louis Etienne Thirioux, an amateur naturalist at Port Louis, also found many dodo remains around 1900 from several locations. They included the first articulated specimen, which is the first subfossil dodo skeleton found outside the Mare aux Songes, and the only remains of a juvenile specimen, a now lost tarsometatarsus. The former specimen was found in 1904 in a cave near Le Pouce mountain, and is the only known complete skeleton of an individual dodo. Thirioux donated the specimen to the Museum Desjardins (now Natural History Museum at Mauritius Institute). Thrioux's heirs sold a second mounted composite skeleton (composed of at least two skeletons, with a mainly reconstructed skull) to the Durban Museum of Natural Science in South Africa in 1918. Together, these two skeletons represent the most completely known dodo remains, including bone elements previously unrecorded (such as knee-caps and wing bones). Though some contemporary writers noted the importance of Thrioux's specimens, they were not scientifically studied, and were largely forgotten until 2011, when sought out by a group of researchers. The mounted skeletons were laser scanned, from which 3-D models were reconstructed, which became the basis of a 2016 monograph about the osteology of the dodo. In 2006, explorers discovered a complete skeleton of a dodo in a lava cave in Mauritius. This was only the second associated skeleton of an individual specimen ever found, and the only one in recent times.",
"title": "Physical remains"
},
{
"paragraph_id": 74,
"text": "Worldwide, 26 museums have significant holdings of dodo material, almost all found in the Mare aux Songes. The Natural History Museum, American Museum of Natural History, Cambridge University Museum of Zoology, the Senckenberg Museum, and others have almost complete skeletons, assembled from the dissociated subfossil remains of several individuals. In 2011, a wooden box containing dodo bones from the Edwardian era was rediscovered at the Grant Museum at University College London during preparations for a move. They had been stored with crocodile bones until then.",
"title": "Physical remains"
},
{
"paragraph_id": 75,
"text": "",
"title": "White dodo"
},
{
"paragraph_id": 76,
"text": "The supposed \"white dodo\" (or \"solitaire\") of Réunion is now considered an erroneous conjecture based on contemporary reports of the Réunion ibis and 17th-century paintings of white, dodo-like birds by Pieter Withoos and Pieter Holsteyn that surfaced in the 19th century. The confusion began when Willem Ysbrandtszoon Bontekoe, who visited Réunion around 1619, mentioned fat, flightless birds that he referred to as \"Dod-eersen\" in his journal, though without mentioning their colouration. When the journal was published in 1646, it was accompanied by an engraving of a dodo from Savery's \"Crocker Art Gallery sketch\". A white, stocky, and flightless bird was first mentioned as part of the Réunion fauna by Chief Officer J. Tatton in 1625. Sporadic mentions were subsequently made by Sieur Dubois and other contemporary writers.",
"title": "White dodo"
},
{
"paragraph_id": 77,
"text": "Baron Edmond de Sélys Longchamps coined the name Raphus solitarius for these birds in 1848, as he believed the accounts referred to a species of dodo. When 17th-century paintings of white dodos were discovered by 19th-century naturalists, it was assumed they depicted these birds. Oudemans suggested that the discrepancy between the paintings and the old descriptions was that the paintings showed females, and that the species was therefore sexually dimorphic. Some authors also believed the birds described were of a species similar to the Rodrigues solitaire, as it was referred to by the same name, or even that there were white species of both dodo and solitaire on the island.",
"title": "White dodo"
},
{
"paragraph_id": 78,
"text": "The Pieter Withoos painting, which was discovered first, appears to be based on an earlier painting by Pieter Holsteyn, three versions of which are known to have existed. According to Hume, Cheke, and Valledor de Lozoya, it appears that all depictions of white dodos were based on Roelant Savery's painting Landscape with Orpheus and the animals, or on copies of it. The painting has generally been dated to 1611, though a post-1614, or even post-1626, date has also been proposed. The painting shows a whitish specimen and was apparently based on a stuffed specimen then in Prague; a walghvogel described as having a \"dirty off-white colouring\" was mentioned in an inventory of specimens in the Prague collection of the Holy Roman Emperor Rudolf II, to whom Savery was contracted at the time (1607–1611). Savery's several later images all show greyish birds, possibly because he had by then seen another specimen. Cheke and Hume believe the painted specimen was white, owing to albinism. Valledor de Lozoya has instead suggested that the light plumage was a juvenile trait, a result of bleaching of old taxidermy specimens, or simply artistic license.",
"title": "White dodo"
},
{
"paragraph_id": 79,
"text": "In 1987, scientists described fossils of a recently extinct species of ibis from Réunion with a relatively short beak, Borbonibis latipes, before a connection to the solitaire reports had been made. Cheke suggested to one of the authors, Francois Moutou, that the fossils may have been of the Réunion solitaire, and this suggestion was published in 1995. The ibis was reassigned to the genus Threskiornis, now combined with the specific epithet solitarius from the binomial R. solitarius. Birds of this genus are also white and black with slender beaks, fitting the old descriptions of the Réunion solitaire. No fossil remains of dodo-like birds have ever been found on the island.",
"title": "White dodo"
},
{
"paragraph_id": 80,
"text": "The dodo's significance as one of the best-known extinct animals and its singular appearance led to its use in literature and popular culture as a symbol of an outdated concept or object, as in the expression \"dead as a dodo,\" which has come to mean unquestionably dead or obsolete. Similarly, the phrase \"to go the way of the dodo\" means to become extinct or obsolete, to fall out of common usage or practice, or to become a thing of the past. \"Dodo\" is also a slang term for a stupid, dull-witted person, as it was said to be stupid and easily caught.",
"title": "Cultural significance"
},
{
"paragraph_id": 81,
"text": "The dodo appears frequently in works of popular fiction, and even before its extinction, it was featured in European literature, as a symbol for exotic lands, and of gluttony, due to its apparent fatness. In 1865, the same year that George Clark started to publish reports about excavated dodo fossils, the newly vindicated bird was featured as a character in Lewis Carroll's Alice's Adventures in Wonderland. It is thought that he included the dodo because he identified with it and had adopted the name as a nickname for himself because of his stammer, which made him accidentally introduce himself as \"Do-do-dodgson\", his legal surname. Carroll and the girl who served as inspiration for Alice, Alice Liddell, had enjoyed visiting the Oxford museum to see the dodo remains there. The book's popularity made the dodo a well-known icon of extinction. Popular depictions of the dodo often became more exaggerated and cartoonish following its Alice in Wonderland fame, which was in line with the inaccurate belief that it was clumsy, tragic, and destined for extinction.",
"title": "Cultural significance"
},
{
"paragraph_id": 82,
"text": "The dodo is used as a mascot for many kinds of products, especially in Mauritius. It appears as a supporter on the coat of arms of Mauritius, on Mauritius coins, is used as a watermark on all Mauritian rupee banknotes, and features as the background of the Mauritian immigration form. A smiling dodo is the symbol of the Brasseries de Bourbon, a popular brewer on Réunion, whose emblem displays the white species once thought to have lived there.",
"title": "Cultural significance"
},
{
"paragraph_id": 83,
"text": "The dodo is used to promote the protection of endangered species by environmental organisations, such as the Durrell Wildlife Conservation Trust and the Durrell Wildlife Park. The Center for Biological Diversity gives an annual 'Rubber Dodo Award', to \"those who have done the most to destroy wild places, species and biological diversity\". In 2011, the nephiline spider Nephilengys dodo, which inhabits the same woods as the dodo once did, was named after the bird to raise awareness of the urgent need for protection of the Mauritius biota. Two species of ant from Mauritius have been named after the dodo: Pseudolasius dodo in 1946 and Pheidole dodo in 2013. A species of isopod from a coral reef off Réunion was named Hansenium dodo in 1991.",
"title": "Cultural significance"
},
{
"paragraph_id": 84,
"text": "The name dodo has been used by scientists naming genetic elements, honouring the dodo's flightless nature. A fruitfly gene within a region of a chromosome required for flying ability was named \"dodo\". In addition, a defective transposable element family from Phytophthora infestans was named DodoPi as it contained mutations that eliminated the element's ability to jump to new locations in a chromosome.",
"title": "Cultural significance"
},
{
"paragraph_id": 85,
"text": "In 2009, a previously unpublished 17th-century Dutch illustration of a dodo went for sale at Christie's and was expected to sell for £6,000. It is unknown whether the illustration was based on a specimen or on a previous image, and the artist is unidentified. It sold for £44,450. Parrish suggested it depicts a stuffed specimen, as the legs look dried.",
"title": "Cultural significance"
},
{
"paragraph_id": 86,
"text": "The poet Hilaire Belloc included the following poem about the dodo in his Bad Child's Book of Beasts from 1896:",
"title": "Cultural significance"
},
{
"paragraph_id": 87,
"text": "The Dodo used to walk around, And take the sun and air. The sun yet warms his native ground – The Dodo is not there!",
"title": "Cultural significance"
},
{
"paragraph_id": 88,
"text": "The voice which used to squawk and squeak Is now for ever dumb – Yet may you see his bones and beak All in the Mu-se-um.",
"title": "Cultural significance"
},
{
"paragraph_id": 89,
"text": "",
"title": "External links"
}
] | The dodo is an extinct flightless bird that was endemic to the island of Mauritius, which is east of Madagascar in the Indian Ocean. The dodo's closest relative was the also-extinct and flightless Rodrigues solitaire. The two formed the subfamily Raphinae, a clade of extinct flightless birds that were a part of the family which includes pigeons and doves. The closest living relative of the dodo is the Nicobar pigeon. A white dodo was once thought to have existed on the nearby island of Réunion, but it is now believed that this assumption was merely confusion based on the also-extinct Réunion ibis and paintings of white dodos. Subfossil remains show the dodo measured around 62.6–75 centimetres (2.05–2.46 ft) in height and may have weighed 10.6–17.5 kg (23–39 lb) in the wild. The dodo's appearance in life is evidenced only by drawings, paintings, and written accounts from the 17th century. Since these portraits vary considerably, and since only some of the illustrations are known to have been drawn from live specimens, the dodos' exact appearance in life remains unresolved, and little is known about its behaviour. It has been depicted with brownish-grey plumage, yellow feet, a tuft of tail feathers, a grey, naked head, and a black, yellow, and green beak. It used gizzard stones to help digest its food, which is thought to have included fruits, and its main habitat is believed to have been the woods in the drier coastal areas of Mauritius. One account states its clutch consisted of a single egg. It is presumed that the dodo became flightless because of the ready availability of abundant food sources and a relative absence of predators on Mauritius. Though the dodo has historically been portrayed as being fat and clumsy, it is now thought to have been well-adapted for its ecosystem. The first recorded mention of the dodo was by Dutch sailors in 1598. In the following years, the bird was hunted by sailors and invasive species, while its habitat was being destroyed. The last widely accepted sighting of a dodo was in 1662. Its extinction was not immediately noticed, and some considered the bird to be a myth. In the 19th century, research was conducted on a small quantity of remains of four specimens that had been brought to Europe in the early 17th century. Among these is a dried head, the only soft tissue of the dodo that remains today. Since then, a large amount of subfossil material has been collected on Mauritius, mostly from the Mare aux Songes swamp. The extinction of the dodo within less than a century of its discovery called attention to the previously unrecognised problem of human involvement in the disappearance of entire species. The dodo achieved widespread recognition from its role in the story of Alice's Adventures in Wonderland, and it has since become a fixture in popular culture, often as a symbol of extinction and obsolescence. | 2001-09-10T18:29:51Z | 2023-12-15T23:04:04Z | [
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] | https://en.wikipedia.org/wiki/Dodo |
8,421 | Sideroxylon grandiflorum | Sideroxylon grandiflorum, also known as the tambalacoque or dodo tree, is a long-lived species of tree in the sapote family Sapotaceae. It is endemic to Mauritius.
The fruit of Sideroxylon grandiflorum is analogous to a peach. They are both termed drupes because both have a hard endocarp, or pit, surrounding the seed. The plant itself superficially resembles the unrelated Plumeria, but the dodo tree's flowers and fruit are cauliflorous.
In 1973, it was thought that the species was becoming extinct. There were supposedly only 13 specimens left, all estimated to be about 300 years old. The true age could not be determined because tambalacoque has no growth rings. Stanley Temple hypothesized that the dodo, which became extinct in the 17th century, ate tambalacoque fruits, and only by passing through the digestive tract of the dodo could the seeds germinate. Temple (1977) force-fed seventeen tambalacoque fruits to wild turkeys. Seven of the fruits were crushed by the bird's gizzard. The remaining ten were either regurgitated or passed with the bird's feces. Temple planted the remaining ten fruits and three germinated. Temple did not try to germinate any seeds from control fruits not fed to turkeys so the effect of feeding fruits to turkeys was unclear. Reports made on tambalacoque seed germination by Hill (1941) and King (1946) found the seeds germinated without abrading.
Temple's hypothesis that the tree required the dodo was contested. Others have suggested the decline of the tree was exaggerated, or that other extinct animals may also have been distributing the seeds, such as giant tortoises, fruit bats or the broad-billed parrot. The difference in numbers is because young trees are not distinct in appearance and may easily be confused with similar species. The decline of the tree may possibly be due to introduction of domestic pigs and crab-eating macaques, and competition from introduced plants. Catling (2001) in a summary cites Owadally and Temple (1979), and Witmer (1991). Hershey (2004) reviewed the flaws in Temple's dodo-tambalacoque hypothesis.
In 2004, the Botanical Society of America's Plant Science Bulletin disputed Temple's research as flawed. The Bulletin published evidence as to why the dodo's extinction did not directly cause the increasing disappearance of young trees, including suggestions that the Cylindraspis giant tortoises would have been more likely to disperse the seeds than dodos, casting doubt on Temple's view as to the dodo and the tree's sole survival relationship.
This dodo tree is highly valued for its wood in Mauritius, which has led some foresters to scrape the pits by hand to make them sprout and grow. | [
{
"paragraph_id": 0,
"text": "Sideroxylon grandiflorum, also known as the tambalacoque or dodo tree, is a long-lived species of tree in the sapote family Sapotaceae. It is endemic to Mauritius.",
"title": ""
},
{
"paragraph_id": 1,
"text": "The fruit of Sideroxylon grandiflorum is analogous to a peach. They are both termed drupes because both have a hard endocarp, or pit, surrounding the seed. The plant itself superficially resembles the unrelated Plumeria, but the dodo tree's flowers and fruit are cauliflorous.",
"title": "Description"
},
{
"paragraph_id": 2,
"text": "In 1973, it was thought that the species was becoming extinct. There were supposedly only 13 specimens left, all estimated to be about 300 years old. The true age could not be determined because tambalacoque has no growth rings. Stanley Temple hypothesized that the dodo, which became extinct in the 17th century, ate tambalacoque fruits, and only by passing through the digestive tract of the dodo could the seeds germinate. Temple (1977) force-fed seventeen tambalacoque fruits to wild turkeys. Seven of the fruits were crushed by the bird's gizzard. The remaining ten were either regurgitated or passed with the bird's feces. Temple planted the remaining ten fruits and three germinated. Temple did not try to germinate any seeds from control fruits not fed to turkeys so the effect of feeding fruits to turkeys was unclear. Reports made on tambalacoque seed germination by Hill (1941) and King (1946) found the seeds germinated without abrading.",
"title": "Ecology"
},
{
"paragraph_id": 3,
"text": "Temple's hypothesis that the tree required the dodo was contested. Others have suggested the decline of the tree was exaggerated, or that other extinct animals may also have been distributing the seeds, such as giant tortoises, fruit bats or the broad-billed parrot. The difference in numbers is because young trees are not distinct in appearance and may easily be confused with similar species. The decline of the tree may possibly be due to introduction of domestic pigs and crab-eating macaques, and competition from introduced plants. Catling (2001) in a summary cites Owadally and Temple (1979), and Witmer (1991). Hershey (2004) reviewed the flaws in Temple's dodo-tambalacoque hypothesis.",
"title": "Ecology"
},
{
"paragraph_id": 4,
"text": "In 2004, the Botanical Society of America's Plant Science Bulletin disputed Temple's research as flawed. The Bulletin published evidence as to why the dodo's extinction did not directly cause the increasing disappearance of young trees, including suggestions that the Cylindraspis giant tortoises would have been more likely to disperse the seeds than dodos, casting doubt on Temple's view as to the dodo and the tree's sole survival relationship.",
"title": "Ecology"
},
{
"paragraph_id": 5,
"text": "This dodo tree is highly valued for its wood in Mauritius, which has led some foresters to scrape the pits by hand to make them sprout and grow.",
"title": "Uses"
}
] | Sideroxylon grandiflorum, also known as the tambalacoque or dodo tree, is a long-lived species of tree in the sapote family Sapotaceae. It is endemic to Mauritius. | 2001-09-10T18:17:34Z | 2023-08-27T01:45:34Z | [
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8,425 | Dwight Schultz | William Dwight Schultz (born November 24, 1947) is an American television, film and voice actor.
He is known for his roles as Captain "Howling Mad" Murdock on the 1980s action series The A-Team and as Reginald Barclay in the Star Trek franchise.
He is also known in animation as the mad scientist Dr. Animo in the Ben 10 series, Adrian Toomes/Vulture in some Marvel video games, Chef Mung Daal in the children's animated series Chowder, and Eddie the Squirrel in CatDog.
Schultz was born in Baltimore on November 24, 1947. He is of German descent and a Roman Catholic. He attended Calvert Hall College High School and Towson University.
Schultz's breakthrough role was that of Captain "Howling Mad" Murdock on The A-Team. He appeared in several films, including The Fan (1981), and he starred in Fat Man and Little Boy (1989) as J. Robert Oppenheimer. In the early 1990s, he had a recurring role as Lieutenant Reginald Barclay in Star Trek: The Next Generation; he reprised the role in Star Trek: Voyager and the film Star Trek: First Contact. He played in the 1992 television film Child of Rage, starring opposite Mel Harris as a compassionate couple who adopt a troubled girl who has been sexually abused. In November 2009, Schultz confirmed that he and former A-Team co-star Dirk Benedict would make cameo appearances in the feature film The A-Team.
Schultz hosted a conservative talk-radio podcast called Howling Mad Radio which ended in March 2009. He has also guest-hosted on numerous occasions for Michael Savage on The Savage Nation, Jerry Doyle on The Jerry Doyle Show, and Rusty Humphries on The Rusty Humphries Show. He also posts political commentaries and podcasts on his official fansite. Schultz has also written for Breitbart where he likened liberalism to mental illness, and has similarly suggested that President Barack Obama's administration may intend to force sex reassignment surgery onto him and others.
Schultz married actress Wendy Fulton in 1983. Their daughter Ava (born 1987) serves in the United States Marine Corps.
Schultz is a Roman Catholic and a conservative. In 2012 he began regular appearances on The Glazov Gang, an Internet political talk show hosted by Jamie Glazov, managing editor of FrontPage Magazine. | [
{
"paragraph_id": 0,
"text": "William Dwight Schultz (born November 24, 1947) is an American television, film and voice actor.",
"title": ""
},
{
"paragraph_id": 1,
"text": "He is known for his roles as Captain \"Howling Mad\" Murdock on the 1980s action series The A-Team and as Reginald Barclay in the Star Trek franchise.",
"title": ""
},
{
"paragraph_id": 2,
"text": "He is also known in animation as the mad scientist Dr. Animo in the Ben 10 series, Adrian Toomes/Vulture in some Marvel video games, Chef Mung Daal in the children's animated series Chowder, and Eddie the Squirrel in CatDog.",
"title": ""
},
{
"paragraph_id": 3,
"text": "Schultz was born in Baltimore on November 24, 1947. He is of German descent and a Roman Catholic. He attended Calvert Hall College High School and Towson University.",
"title": "Early life"
},
{
"paragraph_id": 4,
"text": "Schultz's breakthrough role was that of Captain \"Howling Mad\" Murdock on The A-Team. He appeared in several films, including The Fan (1981), and he starred in Fat Man and Little Boy (1989) as J. Robert Oppenheimer. In the early 1990s, he had a recurring role as Lieutenant Reginald Barclay in Star Trek: The Next Generation; he reprised the role in Star Trek: Voyager and the film Star Trek: First Contact. He played in the 1992 television film Child of Rage, starring opposite Mel Harris as a compassionate couple who adopt a troubled girl who has been sexually abused. In November 2009, Schultz confirmed that he and former A-Team co-star Dirk Benedict would make cameo appearances in the feature film The A-Team.",
"title": "Career"
},
{
"paragraph_id": 5,
"text": "Schultz hosted a conservative talk-radio podcast called Howling Mad Radio which ended in March 2009. He has also guest-hosted on numerous occasions for Michael Savage on The Savage Nation, Jerry Doyle on The Jerry Doyle Show, and Rusty Humphries on The Rusty Humphries Show. He also posts political commentaries and podcasts on his official fansite. Schultz has also written for Breitbart where he likened liberalism to mental illness, and has similarly suggested that President Barack Obama's administration may intend to force sex reassignment surgery onto him and others.",
"title": "Career"
},
{
"paragraph_id": 6,
"text": "Schultz married actress Wendy Fulton in 1983. Their daughter Ava (born 1987) serves in the United States Marine Corps.",
"title": "Personal life"
},
{
"paragraph_id": 7,
"text": "Schultz is a Roman Catholic and a conservative. In 2012 he began regular appearances on The Glazov Gang, an Internet political talk show hosted by Jamie Glazov, managing editor of FrontPage Magazine.",
"title": "Personal life"
}
] | William Dwight Schultz is an American television, film and voice actor. He is known for his roles as Captain "Howling Mad" Murdock on the 1980s action series The A-Team and as Reginald Barclay in the Star Trek franchise. He is also known in animation as the mad scientist Dr. Animo in the Ben 10 series, Adrian Toomes/Vulture in some Marvel video games, Chef Mung Daal in the children's animated series Chowder, and Eddie the Squirrel in CatDog. | 2001-09-11T09:58:02Z | 2023-12-25T04:17:06Z | [
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8,429 | Density | Density (volumetric mass density or specific mass) is a substance's mass per unit of volume. The symbol most often used for density is ρ (the lower case Greek letter rho), although the Latin letter D can also be used. Mathematically, density is defined as mass divided by volume:
where ρ is the density, m is the mass, and V is the volume. In some cases (for instance, in the United States oil and gas industry), density is loosely defined as its weight per unit volume, although this is scientifically inaccurate – this quantity is more specifically called specific weight.
For a pure substance the density has the same numerical value as its mass concentration. Different materials usually have different densities, and density may be relevant to buoyancy, purity and packaging. Osmium is the densest known element at standard conditions for temperature and pressure.
To simplify comparisons of density across different systems of units, it is sometimes replaced by the dimensionless quantity "relative density" or "specific gravity", i.e. the ratio of the density of the material to that of a standard material, usually water. Thus a relative density less than one relative to water means that the substance floats in water.
The density of a material varies with temperature and pressure. This variation is typically small for solids and liquids but much greater for gases. Increasing the pressure on an object decreases the volume of the object and thus increases its density. Increasing the temperature of a substance (with a few exceptions) decreases its density by increasing its volume. In most materials, heating the bottom of a fluid results in convection of the heat from the bottom to the top, due to the decrease in the density of the heated fluid, which causes it to rise relative to denser unheated material.
The reciprocal of the density of a substance is occasionally called its specific volume, a term sometimes used in thermodynamics. Density is an intensive property in that increasing the amount of a substance does not increase its density; rather it increases its mass.
Other conceptually comparable quantities or ratios include specific density, relative density (specific gravity), and specific weight.
The understanding that different materials have different densities, and of a relationship between density, floating, and sinking must date to prehistoric times. Much later it was put in writing. Aristotle, for example, wrote:
There is so great a difference in density between salt and fresh water that vessels laden with cargoes of the same weight almost sink in rivers, but ride quite easily at sea and are quite seaworthy. And an ignorance of this has sometimes cost people dear who load their ships in rivers. The following is a proof that the density of a fluid is greater when a substance is mixed with it. If you make water very salt by mixing salt in with it, eggs will float on it. ... If there were any truth in the stories they tell about the lake in Palestine it would further bear out what I say. For they say if you bind a man or beast and throw him into it he floats and does not sink beneath the surface.
In a well-known but probably apocryphal tale, Archimedes was given the task of determining whether King Hiero's goldsmith was embezzling gold during the manufacture of a golden wreath dedicated to the gods and replacing it with another, cheaper alloy. Archimedes knew that the irregularly shaped wreath could be crushed into a cube whose volume could be calculated easily and compared with the mass; but the king did not approve of this. Baffled, Archimedes is said to have taken an immersion bath and observed from the rise of the water upon entering that he could calculate the volume of the gold wreath through the displacement of the water. Upon this discovery, he leapt from his bath and ran naked through the streets shouting, "Eureka! Eureka!" (Ancient Greek: Εύρηκα!, lit. 'I have found it'). As a result, the term eureka entered common parlance and is used today to indicate a moment of enlightenment.
The story first appeared in written form in Vitruvius' books of architecture, two centuries after it supposedly took place. Some scholars have doubted the accuracy of this tale, saying among other things that the method would have required precise measurements that would have been difficult to make at the time.
Nevertheless, in 1586, Galileo Galilei, in one of his first experiments, made a possible reconstruction of how the experiment could have been performed with ancient Greek resources
From the equation for density (ρ = m/V), mass density has any unit that is mass divided by volume. As there are many units of mass and volume covering many different magnitudes there are a large number of units for mass density in use. The SI unit of kilogram per cubic metre (kg/m) and the cgs unit of gram per cubic centimetre (g/cm) are probably the most commonly used units for density. One g/cm is equal to 1000 kg/m. One cubic centimetre (abbreviation cc) is equal to one millilitre. In industry, other larger or smaller units of mass and or volume are often more practical and US customary units may be used. See below for a list of some of the most common units of density.
The litre and tonne are not part of the SI, but are acceptable for use with it, leading to the following units:
Densities using the following metric units all have exactly the same numerical value, one thousandth of the value in (kg/m). Liquid water has a density of about 1 kg/dm, making any of these SI units numerically convenient to use as most solids and liquids have densities between 0.1 and 20 kg/dm.
In US customary units density can be stated in:
Imperial units differing from the above (as the Imperial gallon and bushel differ from the US units) in practice are rarely used, though found in older documents. The Imperial gallon was based on the concept that an Imperial fluid ounce of water would have a mass of one Avoirdupois ounce, and indeed 1 g/cm ≈ 1.00224129 ounces per Imperial fluid ounce = 10.0224129 pounds per Imperial gallon. The density of precious metals could conceivably be based on Troy ounces and pounds, a possible cause of confusion.
Knowing the volume of the unit cell of a crystalline material and its formula weight (in daltons), the density can be calculated. One dalton per cubic ångström is equal to a density of 1.660 539 066 60 g/cm.
A number of techniques as well as standards exist for the measurement of density of materials. Such techniques include the use of a hydrometer (a buoyancy method for liquids), Hydrostatic balance (a buoyancy method for liquids and solids), immersed body method (a buoyancy method for liquids), pycnometer (liquids and solids), air comparison pycnometer (solids), oscillating densitometer (liquids), as well as pour and tap (solids). However, each individual method or technique measures different types of density (e.g. bulk density, skeletal density, etc.), and therefore it is necessary to have an understanding of the type of density being measured as well as the type of material in question.
The density at all points of a homogeneous object equals its total mass divided by its total volume. The mass is normally measured with a scale or balance; the volume may be measured directly (from the geometry of the object) or by the displacement of a fluid. To determine the density of a liquid or a gas, a hydrometer, a dasymeter or a Coriolis flow meter may be used, respectively. Similarly, hydrostatic weighing uses the displacement of water due to a submerged object to determine the density of the object.
If the body is not homogeneous, then its density varies between different regions of the object. In that case the density around any given location is determined by calculating the density of a small volume around that location. In the limit of an infinitesimal volume the density of an inhomogeneous object at a point becomes: ρ ( r → ) = d m / d V {\displaystyle \rho ({\vec {r}})=dm/dV} , where d V {\displaystyle dV} is an elementary volume at position r → {\displaystyle {\vec {r}}} . The mass of the body then can be expressed as
In practice, bulk materials such as sugar, sand, or snow contain voids. Many materials exist in nature as flakes, pellets, or granules.
Voids are regions which contain something other than the considered material. Commonly the void is air, but it could also be vacuum, liquid, solid, or a different gas or gaseous mixture.
The bulk volume of a material —inclusive of the void space fraction— is often obtained by a simple measurement (e.g. with a calibrated measuring cup) or geometrically from known dimensions.
Mass divided by bulk volume determines bulk density. This is not the same thing as the material volumetric mass density. To determine the material volumetric mass density, one must first discount the volume of the void fraction. Sometimes this can be determined by geometrical reasoning. For the close-packing of equal spheres the non-void fraction can be at most about 74%. It can also be determined empirically. Some bulk materials, however, such as sand, have a variable void fraction which depends on how the material is agitated or poured. It might be loose or compact, with more or less air space depending on handling.
In practice, the void fraction is not necessarily air, or even gaseous. In the case of sand, it could be water, which can be advantageous for measurement as the void fraction for sand saturated in water—once any air bubbles are thoroughly driven out—is potentially more consistent than dry sand measured with an air void.
In the case of non-compact materials, one must also take care in determining the mass of the material sample. If the material is under pressure (commonly ambient air pressure at the earth's surface) the determination of mass from a measured sample weight might need to account for buoyancy effects due to the density of the void constituent, depending on how the measurement was conducted. In the case of dry sand, sand is so much denser than air that the buoyancy effect is commonly neglected (less than one part in one thousand).
Mass change upon displacing one void material with another while maintaining constant volume can be used to estimate the void fraction, if the difference in density of the two voids materials is reliably known.
In general, density can be changed by changing either the pressure or the temperature. Increasing the pressure always increases the density of a material. Increasing the temperature generally decreases the density, but there are notable exceptions to this generalization. For example, the density of water increases between its melting point at 0 °C and 4 °C; similar behavior is observed in silicon at low temperatures.
The effect of pressure and temperature on the densities of liquids and solids is small. The compressibility for a typical liquid or solid is 10 bar (1 bar = 0.1 MPa) and a typical thermal expansivity is 10 K. This roughly translates into needing around ten thousand times atmospheric pressure to reduce the volume of a substance by one percent. (Although the pressures needed may be around a thousand times smaller for sandy soil and some clays.) A one percent expansion of volume typically requires a temperature increase on the order of thousands of degrees Celsius.
In contrast, the density of gases is strongly affected by pressure. The density of an ideal gas is
where M is the molar mass, P is the pressure, R is the universal gas constant, and T is the absolute temperature. This means that the density of an ideal gas can be doubled by doubling the pressure, or by halving the absolute temperature.
In the case of volumic thermal expansion at constant pressure and small intervals of temperature the temperature dependence of density is
where ρ T 0 {\displaystyle \rho _{T_{0}}} is the density at a reference temperature, α {\displaystyle \alpha } is the thermal expansion coefficient of the material at temperatures close to T 0 {\displaystyle T_{0}} .
The density of a solution is the sum of mass (massic) concentrations of the components of that solution.
Mass (massic) concentration of each given component ρ i {\displaystyle \rho _{i}} in a solution sums to density of the solution,
Expressed as a function of the densities of pure components of the mixture and their volume participation, it allows the determination of excess molar volumes:
provided that there is no interaction between the components.
Knowing the relation between excess volumes and activity coefficients of the components, one can determine the activity coefficients: | [
{
"paragraph_id": 0,
"text": "Density (volumetric mass density or specific mass) is a substance's mass per unit of volume. The symbol most often used for density is ρ (the lower case Greek letter rho), although the Latin letter D can also be used. Mathematically, density is defined as mass divided by volume:",
"title": ""
},
{
"paragraph_id": 1,
"text": "where ρ is the density, m is the mass, and V is the volume. In some cases (for instance, in the United States oil and gas industry), density is loosely defined as its weight per unit volume, although this is scientifically inaccurate – this quantity is more specifically called specific weight.",
"title": ""
},
{
"paragraph_id": 2,
"text": "For a pure substance the density has the same numerical value as its mass concentration. Different materials usually have different densities, and density may be relevant to buoyancy, purity and packaging. Osmium is the densest known element at standard conditions for temperature and pressure.",
"title": ""
},
{
"paragraph_id": 3,
"text": "To simplify comparisons of density across different systems of units, it is sometimes replaced by the dimensionless quantity \"relative density\" or \"specific gravity\", i.e. the ratio of the density of the material to that of a standard material, usually water. Thus a relative density less than one relative to water means that the substance floats in water.",
"title": ""
},
{
"paragraph_id": 4,
"text": "The density of a material varies with temperature and pressure. This variation is typically small for solids and liquids but much greater for gases. Increasing the pressure on an object decreases the volume of the object and thus increases its density. Increasing the temperature of a substance (with a few exceptions) decreases its density by increasing its volume. In most materials, heating the bottom of a fluid results in convection of the heat from the bottom to the top, due to the decrease in the density of the heated fluid, which causes it to rise relative to denser unheated material.",
"title": ""
},
{
"paragraph_id": 5,
"text": "The reciprocal of the density of a substance is occasionally called its specific volume, a term sometimes used in thermodynamics. Density is an intensive property in that increasing the amount of a substance does not increase its density; rather it increases its mass.",
"title": ""
},
{
"paragraph_id": 6,
"text": "Other conceptually comparable quantities or ratios include specific density, relative density (specific gravity), and specific weight.",
"title": ""
},
{
"paragraph_id": 7,
"text": "The understanding that different materials have different densities, and of a relationship between density, floating, and sinking must date to prehistoric times. Much later it was put in writing. Aristotle, for example, wrote:",
"title": "History"
},
{
"paragraph_id": 8,
"text": "There is so great a difference in density between salt and fresh water that vessels laden with cargoes of the same weight almost sink in rivers, but ride quite easily at sea and are quite seaworthy. And an ignorance of this has sometimes cost people dear who load their ships in rivers. The following is a proof that the density of a fluid is greater when a substance is mixed with it. If you make water very salt by mixing salt in with it, eggs will float on it. ... If there were any truth in the stories they tell about the lake in Palestine it would further bear out what I say. For they say if you bind a man or beast and throw him into it he floats and does not sink beneath the surface.",
"title": "History"
},
{
"paragraph_id": 9,
"text": "In a well-known but probably apocryphal tale, Archimedes was given the task of determining whether King Hiero's goldsmith was embezzling gold during the manufacture of a golden wreath dedicated to the gods and replacing it with another, cheaper alloy. Archimedes knew that the irregularly shaped wreath could be crushed into a cube whose volume could be calculated easily and compared with the mass; but the king did not approve of this. Baffled, Archimedes is said to have taken an immersion bath and observed from the rise of the water upon entering that he could calculate the volume of the gold wreath through the displacement of the water. Upon this discovery, he leapt from his bath and ran naked through the streets shouting, \"Eureka! Eureka!\" (Ancient Greek: Εύρηκα!, lit. 'I have found it'). As a result, the term eureka entered common parlance and is used today to indicate a moment of enlightenment.",
"title": "History"
},
{
"paragraph_id": 10,
"text": "The story first appeared in written form in Vitruvius' books of architecture, two centuries after it supposedly took place. Some scholars have doubted the accuracy of this tale, saying among other things that the method would have required precise measurements that would have been difficult to make at the time.",
"title": "History"
},
{
"paragraph_id": 11,
"text": "Nevertheless, in 1586, Galileo Galilei, in one of his first experiments, made a possible reconstruction of how the experiment could have been performed with ancient Greek resources",
"title": "History"
},
{
"paragraph_id": 12,
"text": "From the equation for density (ρ = m/V), mass density has any unit that is mass divided by volume. As there are many units of mass and volume covering many different magnitudes there are a large number of units for mass density in use. The SI unit of kilogram per cubic metre (kg/m) and the cgs unit of gram per cubic centimetre (g/cm) are probably the most commonly used units for density. One g/cm is equal to 1000 kg/m. One cubic centimetre (abbreviation cc) is equal to one millilitre. In industry, other larger or smaller units of mass and or volume are often more practical and US customary units may be used. See below for a list of some of the most common units of density.",
"title": "Units"
},
{
"paragraph_id": 13,
"text": "The litre and tonne are not part of the SI, but are acceptable for use with it, leading to the following units:",
"title": "Units"
},
{
"paragraph_id": 14,
"text": "Densities using the following metric units all have exactly the same numerical value, one thousandth of the value in (kg/m). Liquid water has a density of about 1 kg/dm, making any of these SI units numerically convenient to use as most solids and liquids have densities between 0.1 and 20 kg/dm.",
"title": "Units"
},
{
"paragraph_id": 15,
"text": "In US customary units density can be stated in:",
"title": "Units"
},
{
"paragraph_id": 16,
"text": "Imperial units differing from the above (as the Imperial gallon and bushel differ from the US units) in practice are rarely used, though found in older documents. The Imperial gallon was based on the concept that an Imperial fluid ounce of water would have a mass of one Avoirdupois ounce, and indeed 1 g/cm ≈ 1.00224129 ounces per Imperial fluid ounce = 10.0224129 pounds per Imperial gallon. The density of precious metals could conceivably be based on Troy ounces and pounds, a possible cause of confusion.",
"title": "Units"
},
{
"paragraph_id": 17,
"text": "Knowing the volume of the unit cell of a crystalline material and its formula weight (in daltons), the density can be calculated. One dalton per cubic ångström is equal to a density of 1.660 539 066 60 g/cm.",
"title": "Units"
},
{
"paragraph_id": 18,
"text": "A number of techniques as well as standards exist for the measurement of density of materials. Such techniques include the use of a hydrometer (a buoyancy method for liquids), Hydrostatic balance (a buoyancy method for liquids and solids), immersed body method (a buoyancy method for liquids), pycnometer (liquids and solids), air comparison pycnometer (solids), oscillating densitometer (liquids), as well as pour and tap (solids). However, each individual method or technique measures different types of density (e.g. bulk density, skeletal density, etc.), and therefore it is necessary to have an understanding of the type of density being measured as well as the type of material in question.",
"title": "Measurement"
},
{
"paragraph_id": 19,
"text": "The density at all points of a homogeneous object equals its total mass divided by its total volume. The mass is normally measured with a scale or balance; the volume may be measured directly (from the geometry of the object) or by the displacement of a fluid. To determine the density of a liquid or a gas, a hydrometer, a dasymeter or a Coriolis flow meter may be used, respectively. Similarly, hydrostatic weighing uses the displacement of water due to a submerged object to determine the density of the object.",
"title": "Measurement"
},
{
"paragraph_id": 20,
"text": "If the body is not homogeneous, then its density varies between different regions of the object. In that case the density around any given location is determined by calculating the density of a small volume around that location. In the limit of an infinitesimal volume the density of an inhomogeneous object at a point becomes: ρ ( r → ) = d m / d V {\\displaystyle \\rho ({\\vec {r}})=dm/dV} , where d V {\\displaystyle dV} is an elementary volume at position r → {\\displaystyle {\\vec {r}}} . The mass of the body then can be expressed as",
"title": "Measurement"
},
{
"paragraph_id": 21,
"text": "In practice, bulk materials such as sugar, sand, or snow contain voids. Many materials exist in nature as flakes, pellets, or granules.",
"title": "Measurement"
},
{
"paragraph_id": 22,
"text": "Voids are regions which contain something other than the considered material. Commonly the void is air, but it could also be vacuum, liquid, solid, or a different gas or gaseous mixture.",
"title": "Measurement"
},
{
"paragraph_id": 23,
"text": "The bulk volume of a material —inclusive of the void space fraction— is often obtained by a simple measurement (e.g. with a calibrated measuring cup) or geometrically from known dimensions.",
"title": "Measurement"
},
{
"paragraph_id": 24,
"text": "Mass divided by bulk volume determines bulk density. This is not the same thing as the material volumetric mass density. To determine the material volumetric mass density, one must first discount the volume of the void fraction. Sometimes this can be determined by geometrical reasoning. For the close-packing of equal spheres the non-void fraction can be at most about 74%. It can also be determined empirically. Some bulk materials, however, such as sand, have a variable void fraction which depends on how the material is agitated or poured. It might be loose or compact, with more or less air space depending on handling.",
"title": "Measurement"
},
{
"paragraph_id": 25,
"text": "In practice, the void fraction is not necessarily air, or even gaseous. In the case of sand, it could be water, which can be advantageous for measurement as the void fraction for sand saturated in water—once any air bubbles are thoroughly driven out—is potentially more consistent than dry sand measured with an air void.",
"title": "Measurement"
},
{
"paragraph_id": 26,
"text": "In the case of non-compact materials, one must also take care in determining the mass of the material sample. If the material is under pressure (commonly ambient air pressure at the earth's surface) the determination of mass from a measured sample weight might need to account for buoyancy effects due to the density of the void constituent, depending on how the measurement was conducted. In the case of dry sand, sand is so much denser than air that the buoyancy effect is commonly neglected (less than one part in one thousand).",
"title": "Measurement"
},
{
"paragraph_id": 27,
"text": "Mass change upon displacing one void material with another while maintaining constant volume can be used to estimate the void fraction, if the difference in density of the two voids materials is reliably known.",
"title": "Measurement"
},
{
"paragraph_id": 28,
"text": "In general, density can be changed by changing either the pressure or the temperature. Increasing the pressure always increases the density of a material. Increasing the temperature generally decreases the density, but there are notable exceptions to this generalization. For example, the density of water increases between its melting point at 0 °C and 4 °C; similar behavior is observed in silicon at low temperatures.",
"title": "Changes of density"
},
{
"paragraph_id": 29,
"text": "The effect of pressure and temperature on the densities of liquids and solids is small. The compressibility for a typical liquid or solid is 10 bar (1 bar = 0.1 MPa) and a typical thermal expansivity is 10 K. This roughly translates into needing around ten thousand times atmospheric pressure to reduce the volume of a substance by one percent. (Although the pressures needed may be around a thousand times smaller for sandy soil and some clays.) A one percent expansion of volume typically requires a temperature increase on the order of thousands of degrees Celsius.",
"title": "Changes of density"
},
{
"paragraph_id": 30,
"text": "In contrast, the density of gases is strongly affected by pressure. The density of an ideal gas is",
"title": "Changes of density"
},
{
"paragraph_id": 31,
"text": "where M is the molar mass, P is the pressure, R is the universal gas constant, and T is the absolute temperature. This means that the density of an ideal gas can be doubled by doubling the pressure, or by halving the absolute temperature.",
"title": "Changes of density"
},
{
"paragraph_id": 32,
"text": "In the case of volumic thermal expansion at constant pressure and small intervals of temperature the temperature dependence of density is",
"title": "Changes of density"
},
{
"paragraph_id": 33,
"text": "where ρ T 0 {\\displaystyle \\rho _{T_{0}}} is the density at a reference temperature, α {\\displaystyle \\alpha } is the thermal expansion coefficient of the material at temperatures close to T 0 {\\displaystyle T_{0}} .",
"title": "Changes of density"
},
{
"paragraph_id": 34,
"text": "The density of a solution is the sum of mass (massic) concentrations of the components of that solution.",
"title": "Density of solutions"
},
{
"paragraph_id": 35,
"text": "Mass (massic) concentration of each given component ρ i {\\displaystyle \\rho _{i}} in a solution sums to density of the solution,",
"title": "Density of solutions"
},
{
"paragraph_id": 36,
"text": "Expressed as a function of the densities of pure components of the mixture and their volume participation, it allows the determination of excess molar volumes:",
"title": "Density of solutions"
},
{
"paragraph_id": 37,
"text": "provided that there is no interaction between the components.",
"title": "Density of solutions"
},
{
"paragraph_id": 38,
"text": "Knowing the relation between excess volumes and activity coefficients of the components, one can determine the activity coefficients:",
"title": "Density of solutions"
}
] | Density is a substance's mass per unit of volume. The symbol most often used for density is ρ, although the Latin letter D can also be used. Mathematically, density is defined as mass divided by volume: where ρ is the density, m is the mass, and V is the volume. In some cases, density is loosely defined as its weight per unit volume, although this is scientifically inaccurate – this quantity is more specifically called specific weight. For a pure substance the density has the same numerical value as its mass concentration.
Different materials usually have different densities, and density may be relevant to buoyancy, purity and packaging. Osmium is the densest known element at standard conditions for temperature and pressure. To simplify comparisons of density across different systems of units, it is sometimes replaced by the dimensionless quantity "relative density" or "specific gravity", i.e. the ratio of the density of the material to that of a standard material, usually water. Thus a relative density less than one relative to water means that the substance floats in water. The density of a material varies with temperature and pressure. This variation is typically small for solids and liquids but much greater for gases. Increasing the pressure on an object decreases the volume of the object and thus increases its density. Increasing the temperature of a substance decreases its density by increasing its volume. In most materials, heating the bottom of a fluid results in convection of the heat from the bottom to the top, due to the decrease in the density of the heated fluid, which causes it to rise relative to denser unheated material. The reciprocal of the density of a substance is occasionally called its specific volume, a term sometimes used in thermodynamics. Density is an intensive property in that increasing the amount of a substance does not increase its density; rather it increases its mass. Other conceptually comparable quantities or ratios include specific density, relative density, and specific weight. | 2001-09-13T09:07:21Z | 2023-12-05T22:20:49Z | [
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8,432 | Dave Barry | David McAlister Barry (born July 3, 1947) is an American author and columnist who wrote a nationally syndicated humor column for the Miami Herald from 1983 to 2005. He has also written numerous books of humor and parody, as well as comic novels and children's novels. Barry's honors include the Pulitzer Prize for Commentary (1988) and the Walter Cronkite Award for Excellence in Journalism (2005).
Barry has defined a sense of humor as "a measurement of the extent to which we realize that we are trapped in a world almost totally devoid of reason. Laughter is how we express the anxiety we feel at this knowledge."
Barry was born in Armonk, New York, where his father, David W. Barry, was a Presbyterian minister. He was educated at Wampus Elementary School, Harold C. Crittenden Junior High School (both in Armonk), and Pleasantville High School, where he was elected "Class Clown" in 1965. He earned a Bachelor of Arts degree in English from Haverford College in 1969.
As an alumnus of a Quaker-affiliated college, he avoided military service during the Vietnam War by registering as a religious conscientious objector. Notwithstanding his father's vocation, Barry decided "early on" that he was an atheist. He said, "The problem with writing about religion is that you run the risk of offending sincerely religious people, and then they come after you with machetes."
Barry began his journalism career in 1971, working as a general-assignment reporter for the Daily Local News in West Chester, Pennsylvania, near his alma mater, Haverford College. He covered local government and civic events and was promoted to City Editor after about two years. He also started writing a weekly humor column for the paper and began to develop his unique style. He remained at the newspaper through 1974. He then worked briefly as a copy editor at the Associated Press's Philadelphia bureau before joining Burger Associates, a consulting firm.
At Burger, he taught effective writing to business people. In his own words, he "spent nearly eight years trying to get various businesspersons to...stop writing things like 'Enclosed please find the enclosed enclosures,' but...eventually realized that it was hopeless."
In 1981 he wrote a humorous guest column in The Philadelphia Inquirer about watching the birth of his son, which attracted the attention of Gene Weingarten, then an editor of the Miami Herald's Sunday magazine Tropic. Weingarten hired Barry as a humor columnist in 1983. Barry's column was syndicated nationally. Barry won a Pulitzer Prize for Commentary in 1988 for "his consistently effective use of humor as a device for presenting fresh insights into serious concerns."
Barry's first novel, Big Trouble, was published in 1999. The book was adapted into a motion picture directed by Barry Sonnenfeld and starring Tim Allen, Rene Russo, and Patrick Warburton, with a cameo by Barry (deleted in post-production). The movie was originally due for release in September 2001 but was postponed following the September 11, 2001, attacks because the story involved smuggling a nuclear weapon onto an airplane. The film was released in April 2002.
In response to a column in which Barry mocked the cities of Grand Forks, North Dakota, and East Grand Forks, Minnesota, for calling themselves the "Grand Cities", Grand Forks named a sewage pumping station after Barry in January 2002. Barry traveled to Grand Forks for the dedication ceremony.
Articles written by Barry have appeared in publications such as Boating, Home Office Computing, and Reader's Digest, in addition to the Chicken Soup for the Soul inspirational book series. Two of his articles have been included in The Best American Sports Writing series. One of his columns was used as the introduction to the book Pirattitude!: So You Wanna Be a Pirate? Here's How! (ISBN 0-451-21649-0), a follow-up to Barry's role in publicizing International Talk Like a Pirate Day. His books have frequently appeared on The New York Times Best Seller list.
On October 31, 2004, Barry announced that he would be taking an indefinite leave of absence of at least a year from his weekly column to spend more time with his family. In December 2005, Barry said in an interview with Editor & Publisher that he would not resume his weekly column, although he would continue such features as his yearly gift guide, his year-in-review feature, and his blog, as well as an occasional article or column.
In 2005, Barry won the Walter Cronkite Award for Excellence in Journalism.
On Sunday, September 22, 2013, the opening night of the 15th annual Fall for the Book festival in Fairfax, Virginia, Barry was awarded the event's highest honor, the Fairfax Prize, honoring outstanding literary achievement, presented by the Fairfax Library Foundation.
From 1993 to 1997, CBS broadcast the sitcom Dave's World based on the books Dave Barry Turns 40 and Dave Barry's Greatest Hits. The show starred Harry Anderson as Barry and DeLane Matthews as his wife Beth. In an early episode, Barry appeared in a cameo role. After four seasons, the program was canceled shortly after being moved from its "coveted" Monday night slot to the "Friday night death slot", so named because of its association with low viewership.
During college, Barry was in a band called the Federal Duck (the band actually issued a self-titled album on Musicor Records in 1968, but Barry was no longer in the group by that point) while at the Miami Herald, he and several of his colleagues created a band called the Urban Professionals, with Barry on lead guitar and vocals. They performed an original song called "The Tupperware Song" at the Tupperware headquarters in Orlando, Florida.
Beginning in 1992, Barry played lead guitar in the Rock Bottom Remainders, a rock band made up of published authors. (Remainder is a publishing term for a book that doesn't sell.) The band was founded by Barry's sister-in-law, Kathi Kamen Goldmark, for an American Booksellers Association convention, and has also included Stephen King, Amy Tan, Ridley Pearson, Scott Turow, Mitch Albom, Roy Blount Jr., Barbara Kingsolver, Matt Groening, and Barry's brother Sam, among others. The band's members "are not musically skilled, but they are extremely loud," according to Barry. Several high-profile musicians, including Al Kooper, Warren Zevon, and Roger McGuinn, have performed with the band, and Bruce Springsteen sat in at least once. The band's road tour resulted in the book Mid-Life Confidential: The Rock Bottom Remainders Tour America with Three Chords and an Attitude. The Rock Bottom Remainders disbanded in 2012 following Goldmark's death from breast cancer. They have reunited several times, performing at the Tucson Festival of Books in 2016 and 2018.
Beginning in 1984, Barry and Tropic editors Gene Weingarten and Tom Shroder have organized the Tropic Hunt (now the Herald Hunt), an annual puzzlehunt in Miami. A Washington, D.C., spinoff, the Post Hunt, began in 2008.
Barry has run several mock campaigns for President of the United States, running on a libertarian platform. He has also written for the Libertarian Party's national newsletter.
The screen adaptation of Barry's book Dave Barry's Complete Guide to Guys was released in 2005; it is available on DVD.
Barry married Lois Ann Shelnutt in 1969. He married Beth Lenox in 1976. Barry and Lenox worked together at the Daily Local News, where they began their journalism careers on the same day in September 1971; they had one child, Robert, born October 8, 1980. Barry and Lenox divorced in 1993. In 1996, Barry married Miami Herald sportswriter Michelle Kaufman; they had a daughter, Sophie, in 2000.
Barry experienced tragedy in his family: his father and his youngest brother suffered from alcoholism, and his father died in 1984; his sister Mary Katherine was institutionalized for schizophrenia; and his mother died by suicide in 1987.
Barry has had dogs named Goldie, Earnest, Zippy, and now Lucy. All have been mentioned regularly in Barry's columns. | [
{
"paragraph_id": 0,
"text": "David McAlister Barry (born July 3, 1947) is an American author and columnist who wrote a nationally syndicated humor column for the Miami Herald from 1983 to 2005. He has also written numerous books of humor and parody, as well as comic novels and children's novels. Barry's honors include the Pulitzer Prize for Commentary (1988) and the Walter Cronkite Award for Excellence in Journalism (2005).",
"title": ""
},
{
"paragraph_id": 1,
"text": "Barry has defined a sense of humor as \"a measurement of the extent to which we realize that we are trapped in a world almost totally devoid of reason. Laughter is how we express the anxiety we feel at this knowledge.\"",
"title": ""
},
{
"paragraph_id": 2,
"text": "Barry was born in Armonk, New York, where his father, David W. Barry, was a Presbyterian minister. He was educated at Wampus Elementary School, Harold C. Crittenden Junior High School (both in Armonk), and Pleasantville High School, where he was elected \"Class Clown\" in 1965. He earned a Bachelor of Arts degree in English from Haverford College in 1969.",
"title": "Early life and education"
},
{
"paragraph_id": 3,
"text": "As an alumnus of a Quaker-affiliated college, he avoided military service during the Vietnam War by registering as a religious conscientious objector. Notwithstanding his father's vocation, Barry decided \"early on\" that he was an atheist. He said, \"The problem with writing about religion is that you run the risk of offending sincerely religious people, and then they come after you with machetes.\"",
"title": "Early life and education"
},
{
"paragraph_id": 4,
"text": "Barry began his journalism career in 1971, working as a general-assignment reporter for the Daily Local News in West Chester, Pennsylvania, near his alma mater, Haverford College. He covered local government and civic events and was promoted to City Editor after about two years. He also started writing a weekly humor column for the paper and began to develop his unique style. He remained at the newspaper through 1974. He then worked briefly as a copy editor at the Associated Press's Philadelphia bureau before joining Burger Associates, a consulting firm.",
"title": "Writing career"
},
{
"paragraph_id": 5,
"text": "At Burger, he taught effective writing to business people. In his own words, he \"spent nearly eight years trying to get various businesspersons to...stop writing things like 'Enclosed please find the enclosed enclosures,' but...eventually realized that it was hopeless.\"",
"title": "Writing career"
},
{
"paragraph_id": 6,
"text": "In 1981 he wrote a humorous guest column in The Philadelphia Inquirer about watching the birth of his son, which attracted the attention of Gene Weingarten, then an editor of the Miami Herald's Sunday magazine Tropic. Weingarten hired Barry as a humor columnist in 1983. Barry's column was syndicated nationally. Barry won a Pulitzer Prize for Commentary in 1988 for \"his consistently effective use of humor as a device for presenting fresh insights into serious concerns.\"",
"title": "Writing career"
},
{
"paragraph_id": 7,
"text": "Barry's first novel, Big Trouble, was published in 1999. The book was adapted into a motion picture directed by Barry Sonnenfeld and starring Tim Allen, Rene Russo, and Patrick Warburton, with a cameo by Barry (deleted in post-production). The movie was originally due for release in September 2001 but was postponed following the September 11, 2001, attacks because the story involved smuggling a nuclear weapon onto an airplane. The film was released in April 2002.",
"title": "Writing career"
},
{
"paragraph_id": 8,
"text": "In response to a column in which Barry mocked the cities of Grand Forks, North Dakota, and East Grand Forks, Minnesota, for calling themselves the \"Grand Cities\", Grand Forks named a sewage pumping station after Barry in January 2002. Barry traveled to Grand Forks for the dedication ceremony.",
"title": "Writing career"
},
{
"paragraph_id": 9,
"text": "Articles written by Barry have appeared in publications such as Boating, Home Office Computing, and Reader's Digest, in addition to the Chicken Soup for the Soul inspirational book series. Two of his articles have been included in The Best American Sports Writing series. One of his columns was used as the introduction to the book Pirattitude!: So You Wanna Be a Pirate? Here's How! (ISBN 0-451-21649-0), a follow-up to Barry's role in publicizing International Talk Like a Pirate Day. His books have frequently appeared on The New York Times Best Seller list.",
"title": "Writing career"
},
{
"paragraph_id": 10,
"text": "On October 31, 2004, Barry announced that he would be taking an indefinite leave of absence of at least a year from his weekly column to spend more time with his family. In December 2005, Barry said in an interview with Editor & Publisher that he would not resume his weekly column, although he would continue such features as his yearly gift guide, his year-in-review feature, and his blog, as well as an occasional article or column.",
"title": "Writing career"
},
{
"paragraph_id": 11,
"text": "In 2005, Barry won the Walter Cronkite Award for Excellence in Journalism.",
"title": "Writing career"
},
{
"paragraph_id": 12,
"text": "On Sunday, September 22, 2013, the opening night of the 15th annual Fall for the Book festival in Fairfax, Virginia, Barry was awarded the event's highest honor, the Fairfax Prize, honoring outstanding literary achievement, presented by the Fairfax Library Foundation.",
"title": "Writing career"
},
{
"paragraph_id": 13,
"text": "From 1993 to 1997, CBS broadcast the sitcom Dave's World based on the books Dave Barry Turns 40 and Dave Barry's Greatest Hits. The show starred Harry Anderson as Barry and DeLane Matthews as his wife Beth. In an early episode, Barry appeared in a cameo role. After four seasons, the program was canceled shortly after being moved from its \"coveted\" Monday night slot to the \"Friday night death slot\", so named because of its association with low viewership.",
"title": "Dave's World television series"
},
{
"paragraph_id": 14,
"text": "During college, Barry was in a band called the Federal Duck (the band actually issued a self-titled album on Musicor Records in 1968, but Barry was no longer in the group by that point) while at the Miami Herald, he and several of his colleagues created a band called the Urban Professionals, with Barry on lead guitar and vocals. They performed an original song called \"The Tupperware Song\" at the Tupperware headquarters in Orlando, Florida.",
"title": "Music"
},
{
"paragraph_id": 15,
"text": "Beginning in 1992, Barry played lead guitar in the Rock Bottom Remainders, a rock band made up of published authors. (Remainder is a publishing term for a book that doesn't sell.) The band was founded by Barry's sister-in-law, Kathi Kamen Goldmark, for an American Booksellers Association convention, and has also included Stephen King, Amy Tan, Ridley Pearson, Scott Turow, Mitch Albom, Roy Blount Jr., Barbara Kingsolver, Matt Groening, and Barry's brother Sam, among others. The band's members \"are not musically skilled, but they are extremely loud,\" according to Barry. Several high-profile musicians, including Al Kooper, Warren Zevon, and Roger McGuinn, have performed with the band, and Bruce Springsteen sat in at least once. The band's road tour resulted in the book Mid-Life Confidential: The Rock Bottom Remainders Tour America with Three Chords and an Attitude. The Rock Bottom Remainders disbanded in 2012 following Goldmark's death from breast cancer. They have reunited several times, performing at the Tucson Festival of Books in 2016 and 2018.",
"title": "Music"
},
{
"paragraph_id": 16,
"text": "Beginning in 1984, Barry and Tropic editors Gene Weingarten and Tom Shroder have organized the Tropic Hunt (now the Herald Hunt), an annual puzzlehunt in Miami. A Washington, D.C., spinoff, the Post Hunt, began in 2008.",
"title": "Other activities"
},
{
"paragraph_id": 17,
"text": "Barry has run several mock campaigns for President of the United States, running on a libertarian platform. He has also written for the Libertarian Party's national newsletter.",
"title": "Other activities"
},
{
"paragraph_id": 18,
"text": "The screen adaptation of Barry's book Dave Barry's Complete Guide to Guys was released in 2005; it is available on DVD.",
"title": "Other activities"
},
{
"paragraph_id": 19,
"text": "Barry married Lois Ann Shelnutt in 1969. He married Beth Lenox in 1976. Barry and Lenox worked together at the Daily Local News, where they began their journalism careers on the same day in September 1971; they had one child, Robert, born October 8, 1980. Barry and Lenox divorced in 1993. In 1996, Barry married Miami Herald sportswriter Michelle Kaufman; they had a daughter, Sophie, in 2000.",
"title": "Personal life"
},
{
"paragraph_id": 20,
"text": "Barry experienced tragedy in his family: his father and his youngest brother suffered from alcoholism, and his father died in 1984; his sister Mary Katherine was institutionalized for schizophrenia; and his mother died by suicide in 1987.",
"title": "Personal life"
},
{
"paragraph_id": 21,
"text": "Barry has had dogs named Goldie, Earnest, Zippy, and now Lucy. All have been mentioned regularly in Barry's columns.",
"title": "Personal life"
}
] | David McAlister Barry is an American author and columnist who wrote a nationally syndicated humor column for the Miami Herald from 1983 to 2005. He has also written numerous books of humor and parody, as well as comic novels and children's novels. Barry's honors include the Pulitzer Prize for Commentary (1988) and the Walter Cronkite Award for Excellence in Journalism (2005). Barry has defined a sense of humor as "a measurement of the extent to which we realize that we are trapped in a world almost totally devoid of reason. Laughter is how we express the anxiety we feel at this knowledge." | 2001-09-12T17:54:36Z | 2023-10-13T00:39:47Z | [
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] | https://en.wikipedia.org/wiki/Dave_Barry |
8,436 | David Angell | David Lawrence Angell (April 10, 1946 – September 11, 2001) was an American screenwriter and television producer, known for his work in sitcoms. He won multiple Emmy Awards as the creator and executive producer of the sitcoms Wings and Frasier with Peter Casey and David Lee. Angell and his wife Lynn were killed heading home from their vacation on Cape Cod aboard American Airlines Flight 11, the first plane to hit the World Trade Center during the September 11 attacks.
Angell was born in Providence, Rhode Island, to Henry and Mae (née Cooney) Angell. He received a bachelor's degree in English literature from Providence College. He married Lynn Edwards on August 14, 1971. Soon after Angell entered the U.S. Army upon graduation and served at the Pentagon until 1972. He then moved to Boston and worked as a methods analyst at an engineering company and later at an insurance firm in Rhode Island. His brother, the Most Rev. Kenneth Angell, was a Roman Catholic prelate and Bishop of Burlington, Vermont.
Angell moved to Los Angeles in 1977. His first script was sold to the producers of the Annie Flynn series. Five years later, he sold his second script, for the sitcom Archie Bunker's Place. In 1983, he joined Cheers as a staff writer. In 1985, Angell joined forces with Peter Casey and David Lee as Cheers supervising producers/writers. The trio received 37 Emmy Award nominations and won 24 Emmy Awards, including the above-mentioned for Frasier. They also won an Outstanding Comedy Series Emmy for Cheers, in 1989, which Angell, Casey, Lee and the series' other producers shared, and an Outstanding Writing/Comedy Emmy for Cheers, which Angell received in 1984. After working together as producers on Cheers, Angell, Casey and Lee formed Grub Street Productions. In 1990, they created and executive-produced the comedy series Wings.
Angell and his wife Lynn were killed in the 2001 September 11 attacks at the World Trade Center in Manhattan. They were among the passengers of American Airlines Flight 11, who were all killed when the plane struck the North Tower of the complex.
The American Screenwriters Association awards the annual David Angell Humanitarian Award to any individual in the entertainment industry who contributes to global well-being through donations of time, expertise or other support to improve the human condition.
In 2004, The Angell Foundation of Los Angeles, California, awarded Providence College a gift of $2 million for the Smith Center for the Arts.
The two-part episode of Frasier to air after the attacks, "Don Juan in Hell" airing on September 25, 2001, ended with the memorial tribute, "In loving memory of our friends Lynn and David Angell". In "Goodnight, Seattle", the series finale that aired May 13, 2004, Niles Crane and Daphne Moon's son was born, named David in tribute.
At the National 9/11 Memorial, Angell and his wife are memorialized at the North Pool, on Panel N-1, along with other passengers from Flight 11. | [
{
"paragraph_id": 0,
"text": "David Lawrence Angell (April 10, 1946 – September 11, 2001) was an American screenwriter and television producer, known for his work in sitcoms. He won multiple Emmy Awards as the creator and executive producer of the sitcoms Wings and Frasier with Peter Casey and David Lee. Angell and his wife Lynn were killed heading home from their vacation on Cape Cod aboard American Airlines Flight 11, the first plane to hit the World Trade Center during the September 11 attacks.",
"title": ""
},
{
"paragraph_id": 1,
"text": "Angell was born in Providence, Rhode Island, to Henry and Mae (née Cooney) Angell. He received a bachelor's degree in English literature from Providence College. He married Lynn Edwards on August 14, 1971. Soon after Angell entered the U.S. Army upon graduation and served at the Pentagon until 1972. He then moved to Boston and worked as a methods analyst at an engineering company and later at an insurance firm in Rhode Island. His brother, the Most Rev. Kenneth Angell, was a Roman Catholic prelate and Bishop of Burlington, Vermont.",
"title": "Early life"
},
{
"paragraph_id": 2,
"text": "Angell moved to Los Angeles in 1977. His first script was sold to the producers of the Annie Flynn series. Five years later, he sold his second script, for the sitcom Archie Bunker's Place. In 1983, he joined Cheers as a staff writer. In 1985, Angell joined forces with Peter Casey and David Lee as Cheers supervising producers/writers. The trio received 37 Emmy Award nominations and won 24 Emmy Awards, including the above-mentioned for Frasier. They also won an Outstanding Comedy Series Emmy for Cheers, in 1989, which Angell, Casey, Lee and the series' other producers shared, and an Outstanding Writing/Comedy Emmy for Cheers, which Angell received in 1984. After working together as producers on Cheers, Angell, Casey and Lee formed Grub Street Productions. In 1990, they created and executive-produced the comedy series Wings.",
"title": "Career"
},
{
"paragraph_id": 3,
"text": "Angell and his wife Lynn were killed in the 2001 September 11 attacks at the World Trade Center in Manhattan. They were among the passengers of American Airlines Flight 11, who were all killed when the plane struck the North Tower of the complex.",
"title": "Death"
},
{
"paragraph_id": 4,
"text": "The American Screenwriters Association awards the annual David Angell Humanitarian Award to any individual in the entertainment industry who contributes to global well-being through donations of time, expertise or other support to improve the human condition.",
"title": "Legacy"
},
{
"paragraph_id": 5,
"text": "In 2004, The Angell Foundation of Los Angeles, California, awarded Providence College a gift of $2 million for the Smith Center for the Arts.",
"title": "Legacy"
},
{
"paragraph_id": 6,
"text": "The two-part episode of Frasier to air after the attacks, \"Don Juan in Hell\" airing on September 25, 2001, ended with the memorial tribute, \"In loving memory of our friends Lynn and David Angell\". In \"Goodnight, Seattle\", the series finale that aired May 13, 2004, Niles Crane and Daphne Moon's son was born, named David in tribute.",
"title": "Legacy"
},
{
"paragraph_id": 7,
"text": "At the National 9/11 Memorial, Angell and his wife are memorialized at the North Pool, on Panel N-1, along with other passengers from Flight 11.",
"title": "Legacy"
}
] | David Lawrence Angell was an American screenwriter and television producer, known for his work in sitcoms. He won multiple Emmy Awards as the creator and executive producer of the sitcoms Wings and Frasier with Peter Casey and David Lee. Angell and his wife Lynn were killed heading home from their vacation on Cape Cod aboard American Airlines Flight 11, the first plane to hit the World Trade Center during the September 11 attacks. | 2001-09-14T22:08:12Z | 2023-12-27T01:23:29Z | [
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8,437 | Diedrich Hermann Westermann | Diedrich Hermann Westermann (June 24, 1875 – May 31, 1956) was a German missionary, Africanist, and linguist. He substantially extended and revised the work of Carl Meinhof, his teacher, although he rejected some of Meinhof's theories only implicitly. Westermann is seen as one of the founders of modern African linguistics.
He carried out extensive linguistic and anthropological research in the area ranging from Senegal eastwards to the Upper Nile. His linguistic publications cover a wide range of African languages, including the Gbe languages, Nuer, Kpelle, Shilluk, Hausa, and Guang.
Westermann's comparative work, begun in 1911, initially brought together much of today's Niger–Congo and Nilo-Saharan language phyla under the name Sudanic languages. His most important later publication Die westlichen Sudansprachen 1927a divided these into East and West Sudanic languages and laid the basis for what would become Niger–Congo. In this book and a series of associated articles between 1925 and 1928, Westermann both identified a large number of roots that form the basis of our understanding of Niger–Congo and set out the evidence for the coherence of many of the families that constitute it. Much of the classification of African languages associated with Joseph Greenberg actually derives from the work of Westermann.
In 1927 Westermann published a Practical Orthography of African Languages, which became later known as the Westermann script. Subsequently, he published the influential and oft-reprinted Practical Phonetics for Students of African Languages in collaboration with Ida C. Ward (1933).
He was born in Baden near Bremen and also died there. | [
{
"paragraph_id": 0,
"text": "Diedrich Hermann Westermann (June 24, 1875 – May 31, 1956) was a German missionary, Africanist, and linguist. He substantially extended and revised the work of Carl Meinhof, his teacher, although he rejected some of Meinhof's theories only implicitly. Westermann is seen as one of the founders of modern African linguistics.",
"title": ""
},
{
"paragraph_id": 1,
"text": "He carried out extensive linguistic and anthropological research in the area ranging from Senegal eastwards to the Upper Nile. His linguistic publications cover a wide range of African languages, including the Gbe languages, Nuer, Kpelle, Shilluk, Hausa, and Guang.",
"title": ""
},
{
"paragraph_id": 2,
"text": "Westermann's comparative work, begun in 1911, initially brought together much of today's Niger–Congo and Nilo-Saharan language phyla under the name Sudanic languages. His most important later publication Die westlichen Sudansprachen 1927a divided these into East and West Sudanic languages and laid the basis for what would become Niger–Congo. In this book and a series of associated articles between 1925 and 1928, Westermann both identified a large number of roots that form the basis of our understanding of Niger–Congo and set out the evidence for the coherence of many of the families that constitute it. Much of the classification of African languages associated with Joseph Greenberg actually derives from the work of Westermann.",
"title": ""
},
{
"paragraph_id": 3,
"text": "In 1927 Westermann published a Practical Orthography of African Languages, which became later known as the Westermann script. Subsequently, he published the influential and oft-reprinted Practical Phonetics for Students of African Languages in collaboration with Ida C. Ward (1933).",
"title": ""
},
{
"paragraph_id": 4,
"text": "He was born in Baden near Bremen and also died there.",
"title": ""
}
] | Diedrich Hermann Westermann was a German missionary, Africanist, and linguist. He substantially extended and revised the work of Carl Meinhof, his teacher, although he rejected some of Meinhof's theories only implicitly. Westermann is seen as one of the founders of modern African linguistics. He carried out extensive linguistic and anthropological research in the area ranging from Senegal eastwards to the Upper Nile. His linguistic publications cover a wide range of African languages, including the Gbe languages, Nuer, Kpelle, Shilluk, Hausa, and Guang. Westermann's comparative work, begun in 1911, initially brought together much of today's Niger–Congo and Nilo-Saharan language phyla under the name Sudanic languages. His most important later publication Die westlichen Sudansprachen 1927a divided these into East and West Sudanic languages and laid the basis for what would become Niger–Congo. In this book and a series of associated articles between 1925 and 1928, Westermann both identified a large number of roots that form the basis of our understanding of Niger–Congo and set out the evidence for the coherence of many of the families that constitute it. Much of the classification of African languages associated with Joseph Greenberg actually derives from the work of Westermann. In 1927 Westermann published a Practical Orthography of African Languages, which became later known as the Westermann script. Subsequently, he published the influential and oft-reprinted Practical Phonetics for Students of African Languages in collaboration with Ida C. Ward (1933). He was born in Baden near Bremen and also died there. | 2001-09-13T13:12:40Z | 2023-09-22T22:41:53Z | [
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