Norumbega (eller Norumbègue, Nurumbega, osv.) var en legendarisk bebyggelse i det nordøstlige Nordamerika. Ligesom Cathay var det et sagnomspundet navn der måske, måske ikke, har betegnet noget virkeligt. Bynavnet dukkede ofte op på europæiske kort over Nordamerika, liggende syd for Acadia et eller andet sted i det, der nu kaldes "New England" i Nordamerika.

Norumbega blev anset for at være en stor rig by beboet af indfødte. Der har været forsøg på at forbinde navnet og Norumbegalegenden til faktiske arkæologiske steder og selv til forskellige vikinge-beboelser.

Eksterne henvisninger
 Archive.org backup: davistownmuseum.org: The Davistown Museum. The Ancient Dominions of Maine Norumbega Reconsidered and the Wawenoc Diaspora....The Myths of Norumbega Citat: "...The European Discovery of America: The Northern Voyages debunks the 19th century assertion of Norumbega as a Viking name and is the foremost among many historians who assert it is entirely a myth. "Norumbega, apart from the name, which means 'quiet place between two rapids' in Algonkin, was wholly created by European imagination." (pg. 464)..."
 Archive.org backup: nsexplore.ca: The Defences of Norumbega. Professor Eben Norton Horsford. 1891 Citat: "...was written to advance the view of the author that Norse emigrants from the Greenland colony had founded a settlement near Boston, Massachusetts, dating from the beginning of the 11th century...The book itself has been scanned and made available as a sequence of images..."
 30-Apr-2002, The Straight Dope: Did Leif Erikson once live in Cambridge, Massachusetts? Citat: "...Around the intersection of Memorial Drive and Mt. Auburn St. there is a granite plaque in the ground, with the following: "On this spot in the year 1000 Lief Erikson built his house in Vinland."...Horsford did a little digging (literally) and found some buried artifacts that he claimed were Norse. On the spot he built the memorial you saw. He didn't stop there..."
 Hurstwic: Other Norse Artifacts in North America Citat: "...There are a small group of Norse artifacts found in North America that are widely regarded as genuine. These include the artifacts found at L'Anse aux Meadows (left) and the 11th century Norwegian coin found in Maine in 1957 (right)...Norumbega, a Norse Colony in New England?...Williams also recorded that the natives children were often born with white skin and red hair...Chapman's third source of evidence is the over one hundred rune stones found in New England...Horsford continued his research, finding evidence of Norse era dams, canals, piers, and settlements in Watertown, and a Norse era fortification in Waltham. Horsford oversaw the re-creation of the fortification: a stone tower in the Norumbega region of the Charles River (right)..."

Vikingetid
Præcolumbiansk transatlantisk kontakt
Pseudohistorie

Norumbega


Mario Maj is an Italian psychiatrist and professor who has been President of the World Psychiatric Association (2008-2011) and of the European Psychiatric Association (2003-2004). He is the founder and Editor of World Psychiatry, the official journal of the World Psychiatric Association, which has a 2022 impact factor of 73.3. It is ranked no. 1 out of 155 journals in the category Psychiatry and no. 1 out of 144 journals in the Social Science Citation Index (SSCI) category.

Mario Maj has been Chairperson of the Working Group on Mood and Anxiety Disorders and member of the International Advisory Board for the chapter on mental disorders of the International Classification of Diseases, 11th edition (ICD-11), and has been member of the Work Group on Mood Disorders for the American Psychiatric Association's Diagnostic and Statistical Manual of Mental Disorders, 5th edition (DSM-5).

As a researcher, Mario Maj is especially known for his contributions in the area of bipolar disorder, including the clinical characterization of rapid cycling, mixed states,
and psychotic depression, and the study of the determinants of response to prophylaxis with lithium salts.

He has also produced widely quoted editorials on the concept of psychiatric comorbidity, conflicts of interests in psychiatry, and DSM-IV operational diagnostic criteria for schizophrenia.

References

Year of birth missing (living people)
Living people
Italian psychiatrists
World Psychiatric Association
Presidents of the European Psychiatric Association

Mario Maj


The Saif (), sometimes  called a shamshir (from ), depending on the era, originated in Arabia before the 7th century. Little is known about this weapon besides what Al-Kindi wrote in his treatise On Swords in the 9th century.

Description

In the article "Introduction to the Study of Islamic Arms and Armour", A. Rahman Zaky says the saif is "[a]n Arab sword, [with] a rather broad[ ]blade and sometimes with a peculiarly hooked pommel. The size varies greatly. It is found in most countries in which the Arabs have lived, and each has its own variety. Early Arab chroniclers used to mention two kinds of swords: Saif Anith, which was made of iron, and Saif Fulath or Muzakka, which was made of steel."

Etymology

Mostly saif is an Arab word for swords in general, not a certain type. The term Xiphos, Greek for a double-edged straight sword, may be related to saif.

Anatomy

The handle is the miqbad; the pommel, halq; and the quillon, haris. The blade is composed of the false edge and the true edge, which are known as the zafiya or hafat zafiya and the haqiqia, respectively. The sword's point is referred to as the nuqtat.
Some Arab swords may contain a fuller, which is called an 'akmal, but others do not. Therefore the area where the fuller would be is completely flat.

History
The production of the Arab sword has four distinct periods: Pre-Islamic (Ancient swords before the 7th century), Early Islamic (Old swords 7th to 8th centuries), Islamic Golden Age (Swords of the 9th to early-13th centuries) and the Abandonment (Late swords of the late-13th to 16th centuries). Most information on Arab swords come from literature.

Pre-Islamic

Prior to the rise of Islam in the 630s, the settled communities in the Arabian peninsula developed into distinctive civilizations, and are limited to archaeological evidence. Accounts written outside of Arabia and Arab oral traditions were later recorded by Islamic scholars. Among the most prominent civilizations were the Dilmun which arose around the end of the fourth millennium BCE and lasted to about 600CE and the Thamud which arose around 3000BCE and lasted to about 300CE. Additionally, from the beginning of the first millennium BCE, Southern Arabia was the home to a number of kingdoms such as the Sabaeans and the coastal areas of Eastern Arabia were controlled by the Iranian Parthians and Sassanians from 300BCE. The Arabs of the peninsula, thus, had their own local system of warfare, that was not of big armies, but of small battles and skirmishes among tribes.

Early Islamic
Swords in Mu'tah, called Mashrafiya swords, were so highly regarded, that Muhammad ordered in 629 a raid on the city to capture them. In the case of other captured weapons we can be less sure about where they were produced. This is true of the weapons taken from the Jewish tribe known as the Banu Qaynuqa. In his sira the Prophet's biographer Ibn Ishaq, recounts that during the Prophet's life-time this tribe was noted as arms manufacturers, or as possessing large stocks of arms in Medina; it is possible that some of their arms were produced there.

Islamic Golden Age
By the years of the Islamic golden age, the sabers and double-edged swords of the Middle East co-existed.

Abandonment
In the later years of the Arab sword, of the seven listed places by Al-Kindi where it was manufactured, four remained by the later half of the 13th century. With Khorasan and Damascus razed by the Mongols and Byzantium conquered by the Crusaders in the Fourth Crusade, the Arab sword took a strong decline. Its final end came in the 16th century, when the Ottomans seized Egypt in 1517 and Yemen in 1552–60 with the Scimitar, the Shamshir, and the Kilij, thus marking the end of the Arab sword. Neither the Mongols, Crusaders nor Ottomans had shown an interest in the Arab sword. These groups had their own traditions, and thus displaced it. The last two places, Sri Lanka and Kedah, had slowly grown influenced by neighboring traditions and thus ceased to make it altogether.

In c. 1350, Ibn Qayyim al-Jawziyya wrote a treatise on Arab arms called "Al-Furusiyya". In this text, he proclaims that aside from horsemanship, lance and archery, swordsmanship was a fourth discipline of Furusiyya.

Manufacturing

Al-Kindi lists seven places from which Arab swords were forged. Starting with the best; Yemen, Khorasan, Damascus, Egypt, Rum (meaning Byzantium), Sri Lanka and Qalah (possibly Kedah).

Use
During the early Islamic years, the Arabs sheathed their weapons in baldrics. The use of sword and baldric was consciously abandoned by the Abbasid caliph al-Mutawakkil (847-861) in favor of the saber and belt. But the use of sword and baldric seems to have retained a ceremonial and religious significance. For example, the Zangid ruler Nur ad-Din (1146–74) was anxious to demonstrate that he was a pious traditionalist, searching out the old methods preferred by the Prophet. Consequently, among his reforms he re-adopted the custom of wearing a sword suspended from a baldric. His successor Salah ad-Din (1138-1193), known in the west as Saladin, did the same and it is noteworthy that he was buried with his sword, «he took it with him to Paradise.»

According to David Nicolle, the Arab sword was used mainly for cutting. He cites Usama ibn Munqidh's memoir as evidence, that when Usama was being attacked by a Hashshashin, Usama struck the assassin down. Other stories by Usama add credence to David Nicolle's theory.

During the Mamluk period the saber seems to have been the preferred weapon of the warrior elite but the most finely decorated edged weapons were swords. Swords were used in the most important ceremonial events in the Mamluk period, that is, in the investiture of Mamluk sultans and caliphs of the restored Abbasid dynasty where the ruler was «girded» with the «Bedouin sword» saif badawi. There are no surviving descriptions of such swords but it can be suggested as a hypothesis that the exquisitely decorated Mamluk sword blades now preserved in Istanbul are in fact saif badawi.

References

Bibliography
  http://gladius.revistas.csic.es/index.php/gladius/article/viewFile/86/86

  http://gladius.revistas.csic.es/index.php/gladius/article/viewFile/191/193
  http://gladius.revistas.csic.es/index.php/gladius/article/viewFile/211/213

External links

Middle Eastern swords
Arab inventions
Weapons of the Ottoman Empire

Arab sword


Hilltop Manor is an historic apartment complex located in Bladensburg, Prince George's County, Maryland. The complex consists of eight brick garden apartment buildings, each of which is divided into two to six units or sections, constructed in 1942 and 1943.

The structures exhibit characteristics of both the Colonial Revival and Moderne style, reflecting an architectural transition between the traditional elements of the Colonial Revival style and the streamlined features of the Moderne style.

The complex consists of 150 apartments interspersed among eight buildings with 32 units. Each unit contains between four and eight apartments, with the exception of one unit, 5210 53rd Place, which consists of only three apartments. In all, there are five apartment layouts with varying numbers of bedrooms. The majority of the apartments (122) have one bedroom. The remaining apartments consist of two-bedroom apartments; there is one three-bedroom basement apartment. The five basic apartment types, excluding the one three-bedroom apartment, consist of one-bedroom apartments with eat-in kitchens; one-bedroom apartments with separate dining rooms; L-shaped one-bedroom apartments; two-bedroom apartments; and duplex apartments. Despite minor renovations, the interior configurations of the apartments have remained intact.

It was one of the first garden-apartment complexes constructed in the county as a result of the population increase of the Washington metropolitan area during World War II. Hilltop Manor was financed under Section 608 Title VI of the National Housing Act, the primary vehicle for World War II Defense Housing and Federal Housing Administration (FHA) financing. Thus, Hilltop Manor, intended as permanent housing, illustrates the size, scale, and design of garden-apartment complexes constructed during World War II, which was often characterized by temporary housing developments. Hilltop Manor, surrounded by the established streetcar suburb of Defense Heights and adjacent to the new Bladensburg Elementary School, was an alternative to the single-family dwellings in the area and was ideal for young middle-class families. Its location along Defense Highway, which opened in 1927, heightened convenience to Washington, D.C. It is one of the first garden-apartment complexes designed by accomplished local architects Ross & Walton.

It was listed on the National Register of Historic Places in 2007.

References

External links
, at Maryland Historical Trust website

Apartment buildings in Maryland
Buildings and structures in Prince George's County, Maryland
Residential buildings on the National Register of Historic Places in Maryland
Colonial Revival architecture in Maryland
Moderne architecture in Maryland
Residential buildings completed in 1943
National Register of Historic Places in Prince George's County, Maryland
Bladensburg, Maryland

Hilltop Manor (Bladensburg, Maryland)


Active fire protection (AFP) is an integral part of fire protection. AFP is characterized by items and/or systems, which require a certain amount of motion and response in order to work, contrary to passive fire protection.

Categories of active fire protection

Manual fire suppression
Manual fire suppression includes the use of a fire blanket, fire extinguisher, or a standpipe system.

Fire blanket
A fire blanket is a sheet of fire retardant material that is designed to be placed over a fire to smother it out. Small fire blankets are meant for inception stage fires. They are normally made of fiberglass or Kevlar. Larger ones can be found in laboratories and factories, and are designed to be wrapped around a person whose clothes have caught fire.

Fire extinguisher
Fire extinguishers are devices that contain and discharge a substance that extinguishes or puts out a fire. These handheld devices come in a huge range of sizes, but the most common are portable fire extinguishers, typically weighing up to 15 kg in total. These can be easily handled and operated by one person and placement can either be wall-mounted, on a fire extinguisher trolley or housed inside a cabinet. Fire extinguishers are one of the most common manual fire suppression devices and are required in all commercial buildings and vehicles. Fire extinguishers can be used with little to no training and are meant for small incipient stage fires. The most common extinguisher is the ABC extinguisher and are found in most offices and homes. It can be used on normal fires, liquid fires, and electrical fires. There are also special extinguishers for kitchen fires and for use on burning metals, those being Class K and Class D respectively.

Standpipe
Standpipes are installed in most large, multistory buildings.  There are two types of standpipes: dry and wet. Most standpipes are dry systems and cannot be used by the public. Dry systems require a fire engine to pump water into the system. Most dry systems do not have pre-connected hoses and require firefighters to bring in the hose. In wet systems, there is always water in the pipes and they can be used by anyone. Wet systems will have hoses so building occupants can try and extinguish fires. Wet systems are becoming less common with the increase in number of sprinkler systems being installed. In some systems, firefighters have the option of pumping a Fire Department Connection (FDC) which will increase the water pressure at a standpipe in the event of a fire pump failure or loss of pressure. Typically, these systems pressurize the sprinkler system or the standpipe but not both at the same time.

Automatic fire suppression
Automatic control means are any form of suppression that requires no human intervention these can include a fire sprinkler system, a gaseous clean agent, or Automatic foam suppression system. Most automatic suppression systems would be found in large commercial kitchens or other high-risk areas.

Sprinkler systems
Fire sprinkler systems are installed in all types of buildings, commercial and residential. They are usually located at ceiling level and are connected to a reliable water source, most commonly municipal water supply. A typical automatic sprinkler system operates when heat at the site of a fire causes a fusible link or glass component in the sprinkler head to fail, thereby releasing the water from the sprinkler head. This means that only the sprinkler heads at the fire location actuate – not all the sprinklers on a floor or in a building. However, certain systems, such as deluge systems, do spray water from all heads in the same zone upon actuation. Sprinkler systems help to reduce the growth of a fire, thereby increasing life safety and limiting structural damage.

Gaseous clean agent
Gaseous clean agents are installed to result in less fire and water damage than sprinklers, such as in computer rooms. The system works by flooding an area with a gas which interferes with the fire tetrahedron. These systems are often found in areas where people are not going to be present when the system is activated such as datacenters, cooling systems, and other industrial applications. Activating a gaseous clean agent system when people are present can cause injury or death, and are usually equipped with a audible notification system to warn any potential occupants to evacuate the area.

Foam suppression system
Automatic foam suppression systems come in three main forms low expansion, medium expansion, and high expansion.

Low expansion
Low expansion foam expands less than 20 times its original size. These systems can be installed in a variety of places but are commonly found in places where hydrocarbons are stored. Low expansion foam systems when using film forming work by making a blanket of foam over the burning liquid to both cool it down and suppress the vapors.

Medium expansion
Medium expansion foam expands between 20 and 200 times its original size. These can be installed in outdoor settings like transfer stations or for use in open pits. Medium foam is used outdoors because it is denser than high expansion and will not blow away as easily. It works by covering what is on fire in a thick blanket of foam to smother it and suppress vapors.

High expansion
High expansion foam expands between 200 and 1000 times its original size. These systems are commonly installed in large volume areas like airplane hangars, mine shafts, and ship holds. These systems are normally installed inside and make a very light foam. They extinguish the fire by rapid smothering and cooling. Its rapid rate of expansion enables it to fill large areas with foam rapidly. When used on LNG tanks they provide an added insulation layer that helps reduce the vapor rate.

Electronically controlled
Nozzles that are powered by electrical energy that is generated and supplied by fire detection and control devices and are typically closed.

Ignitable Liquid Drainage Floor Assembly (ILDFA)
ILDFA uses a dual approach, combining a water-based fire suppression system in conjunction with a hollow, perforated flooring system to drain and remove spilled flammable liquid. This approach reduces the risk of pool fires inside infrastructure by diverting any leaked fuel away from potential ignition sources or by extinguishing any flammable liquid fire by depriving it of oxygen once it is removed.

Fire detection
Fire detection works using smoke or heat sensors. These systems are very effective tool at alerting people in the immediate vicinity of where the fire is detected but building regulations require an integrated fire detection system. These system not only alerts people throughout the building by triggering the fire alarm but it can also summon emergency services. There are two types of systems available – addressable and conventional. Addressable systems monitor the specific location of each device (e.g. smoke detector, call point or sounder). It means in the event of a fire or other emergency you know exactly where the problem is. This saves precious time and helps the emergency services prevent the loss of life and serious damage. Conventional systems can only determine the problem is in a general area and thus are more suited for small sites.

When the fire detection system is activated it can also send an alert to the local fire department, broadcast a prerecorded warning message and unlock the buildings access control system.

Hypoxic air fire prevention

Fire can be prevented by hypoxic air. Hypoxic air fire prevention systems, also known as oxygen reduction systems are new automatic fire prevention systems that permanently reduce the oxygen concentration inside the protected volumes so that ignition or fire spreading cannot occur. Unlike traditional fire suppression systems that usually extinguish fire after it is detected, hypoxic air is able to prevent fires. At lower altitudes hypoxic air is safe to breathe for healthy individuals.

Construction and maintenance
All AFP systems are required to be installed and maintained in accordance with strict guidelines in order to maintain compliance with the local building code and the fire code.

AFP works alongside modern architectural designs and construction materials and fire safety education to prevent, retard, and suppress structural fires.

See also
 Fire damper
 Fire hydrant
 Fire protection engineering

References

External links
Treatise on Active and Passive Fire Protection from UK Government
When Fire Strikes, Stop, Drop and... Sing? – Article about acoustic fire suppression, Scientific American, January 24, 2008
Karlsruhe Institute of Technology (KIT) - Forschungsstelle für Brandschutztechnik

Fire protection

Active fire protection


Cinchonism or quinism is poisoning from an overdose of cinchona alkaloids. Cinchona bark is the source of quinine and quindine. Quinine is used to treat malaria. In small amounts it is used in tonic water to give a bitter flavor. Cinchoism can be caused by medical doses of quinine or quindine.

Signs and symptoms
Symptoms of mild cinchonism can include:
 flushed and sweaty skin
 ringing of the ears (tinnitus)
 blurred vision
 hearing loss
 confusion
 reversible high-frequency hearing loss
 headache
 abdominal pain
 rashes
 drug-induced lichenoid reaction (lichenoid photosensitivity)
 vertigo
 dizziness
 dysphoria
 nausea
 vomiting
 diarrhea.

Large doses of quinine can cause:
 skin rashes
 deafness
 sleepiness
 blindness
 anaphylactic shock
 disturbances in abnormal heart rhythm
 death from cardiotoxicity.

People treated with quinine may also suffer from low blood sugar and hypotension (low blood pressure).

Most symptoms of cinchonism (except in severe cases) are reversible and disappear once quinine is withdrawn.

References

Poisons
Health problems

Cinchonism


A reaction might refer to:
 Chain reaction
 Chemical reaction, happens when one or more chemicals are changed into one or more other chemicals.
 Light reaction
 Nuclear reaction, a process involving an atomic nucleus or more than one nucleus.
 Reaction (physics) -From Newton's third law: "For every action there is an equal and opposite reaction". The idea that any one force has an opposite force.

Reaction


Manuela Dal Lago (Vicenza, 10 August 1946) is an Italian politician. She is member of Liga Veneta-Lega Nord.

In the late 1970s she started her political career in the Italian Liberal Party, reaching the position of youth leader of the party in Veneto. At that time her followers included Giancarlo Galan, Fabio Gava and Niccolò Ghedini, all leading members of Forza Italia in the Region.

In the early 1990s she joined Liga Veneta, of which she is national president since 2001.

In 1997 Dal Lago was elected President of the Province of Vicenza only with the support of her party, while she was re-elected in 2002 with the support of all the centre-right House of Freedoms coalition.

In the 2008 general election she was elected to the Italian Chamber of Deputies, where she is currently Vice President of the parliamentary group of Lega Nord.

References

1946 births
Living people
People from Vicenza
Italian Liberal Party politicians
Lega Nord politicians
Venetist politicians
Deputies of Legislature XVI of Italy
Politicians of Veneto
20th-century Italian women politicians
21st-century Italian women politicians
Presidents of the Province of Vicenza
Women members of the Chamber of Deputies (Italy)

Manuela Dal Lago


Leucopelargonidin is a colorless chemical compound related to leucoanthocyanins. It can be found in Albizia lebbeck (East Indian walnut), in the fruit of Anacardium occidentale (Cashew), in the fruit of Areca catechu (Areca nut), in the fruit of Hydnocarpus wightiana (Hindi Chaulmoogra), in the rhizome of Rumex hymenosepalus (Arizona dock), in Zea mays (Corn) and in Ziziphus jujuba (Chinese date).

(+)-Leucopelargonidin can be synthesized from (+)-aromadendrin by sodium borohydride reduction.

Metabolism
Dihydrokaempferol 4-reductase uses cis-3,4-leucopelargonidin and NADP+ to produce (+)-aromadendrin, NADPH, and H+.

Leucoanthocyanidin reductase transforms cis-3,4-leucopelargonidin into afzelechin.

References

External links
 Leucopelargonidin and leucocyanidin biosynthesis pathways on biocyc.org

Leucoanthocyanidins
Resorcinols

Leucopelargonidin


Torino Esposizioni is an exhibition hall and convention centre in Turin, Italy which was primarily completed in 1948, designed by Pier Luigi Nervi.

The building is made with primarily ferrocemento and glass. Ferrocemento is a form of concrete construction made with thin cross-sections of concrete and metal wires (reinforcement) with re-usable forms, which Nervi pioneered in Italy and elsewhere.

2006 Olympics
The Torino Esposizioni was converted into a temporary ice rink to host a number of ice hockey events at the 2006 Winter Olympics along with Palasport Olimpico. The temporary arena holds 4,320 people.

The boards in the hockey rink are stiffer than in a permanent facility, while the glass has more give. The facility was converted into an ice rink by laying a sand base and refrigeration pipes into the base, and then freezing water ice atop the substrate. This is similar to the temporary outdoor rink the NHL used for its Heritage Classic game in Edmonton.

After the Olympics were complete, the arena returned to hosting fairs and exhibitions.

In film
The building appears in a deleted scene from the 1969 film The Italian Job. A portion of the car chase was filmed as a dance between the Minis and police cars with a full orchestra playing "The Blue Danube" as accompaniment. The scene appears as an extra on home video releases.

References

External links

 Pier Luigi Nervi | Italian engineer and architect | Britannica
 Exhibition Building, Turin by Pier Luigi Nervi at GreatBuildings
 Turin Exhibition Palace

Indoor arenas in Italy
Indoor ice hockey venues in Italy
Convention centers in Italy
Culture in Turin
Buildings and structures in Turin
Sport in Turin
Venues of the 2006 Winter Olympics
Olympic ice hockey venues
Tourist attractions in Turin
1949 establishments in Italy
Event venues established in 1949
Pier Luigi Nervi buildings

Torino Esposizioni


Eldra "El" Patrick DeBarge (born June 4, 1961) is an American singer, songwriter and musician.
He was the focal point and primary lead singer of the family group DeBarge. Popular songs led by El DeBarge include "Time Will Reveal", "Who's Holding Donna Now", "Stay with Me", "All This Love", and "Rhythm of the Night".

As a solo artist, he is best known for his unique high tenor register, strong falsetto and  hits like "Who's Johnny" and "Love Always". He has also collaborated with artists such as Dionne Warwick, Al Green, Lalah Hathaway, Tone Loc, Babyface, Faith Evans, Quincy Jones, Fourplay, and DJ Quik. DeBarge is a five-time Grammy Award nominee.

Early life
A native of Detroit, Michigan, Eldra was the sixth of the children born to Robert Louis DeBarge Sr. (July 9, 1932 – August 30, 2009)  and Etterlene DeBarge née Abney (born October 13, 1935). According to  Etterlene, Robert was "insanely jealous" and "an extremely abusive father." His parents divorced when DeBarge was 13. DeBarge sang in his local church choir and played piano as a child. Later, after his family moved to Grand Rapids, Michigan, he and the rest of his family began performing at their uncle's Pentecostal church. DeBarge is of African-American and French descent. Growing up, he was closest to his eldest brother Bobby and began imitating his brother's vocal styling.

For several years, DeBarge spent time in private study with music educator Ricky Callier. By 1975, he had begun to express a desire to become a performer. He became a father for the first time at 16 and eventually fathered eleven more children. In 1977, he dropped out of high school and began performing with his elder brothers in clubs and venues in Michigan.

In 1979, Bernd Lichters was able to secure a deal with Source Records/MCA to release the Pall Mall Groove – Hot Ice album as SMASH for the USA/Canada market and moved Eldra from Michigan to Los Angeles, to have him, his brothers Mark and Randy DeBarge, in addition to their cousin Andre Abney, Elliot Townsend, and Stanley Hood, to back up the release as the SMASH band. His eldest sister Bunny joined her brothers in California. In 1980, because of the success of their brothers Bobby and Tommy DeBarge with the hit group Switch, Eldra was able to perform live at the piano and sing in front of Motown CEO Berry Gordy, who immediately signed the group, then known as The DeBarges, to the label.

Motown mentored them, and members later worked with and contributed songwriting, arrangements, and production to the recordings of Switch, including the 1980 albums This Is My Dream and Reaching for Tomorrow. Eldra's first professional recording was as background vocalist to Switch's 1979 hit "I Call Your Name". He later helped to arrange music for several Switch songs including "Love Over and Over Again" and "My Friend in the Sky," which he, Bunny, and Bobby wrote. This song would later be sampled by the likes of Queen Pen and Raheem DeVaughn.

Career

In 1981, The DeBarges was released after the family had worked in the studio for a year recording it. The album was noted for most of its songs produced and written by all four family members including Bobby DeBarge, who helped end the album track "Queen of My Heart" after DeBarge had led the song for most of its tenure. The following album, 1982's All This Love, featured younger brother James and saw much success with the compositions "I Like It" and the title track. Eldra would remain the producer and arranger for all of the group's Motown albums.

In 1983, DeBarge released In a Special Way, which spawned the hits "Time Will Reveal" and "Love Me in a Special Way", and in 1984, the band became a sensation while touring for Luther Vandross on the singer's Busy Body tour. Though the group enjoyed much success and appeared to be a family unit, there were growing tensions between Eldra and his brothers, mainly because of Motown's push to have him to become the only noted star of the group, repeating a pattern that began with Smokey Robinson and The Miracles. By the end of the tour, Eldra was mainly called to handle the production of DeBarge's next album, Rhythm of the Night, without much help from his siblings. The DeBarge family had one more album, Bad Boys, although Eldra and Bunny were not on the album.

Rhythm of the Night became the group's best-selling album ever, although some contended that Eldra was the only member present on the album with the exception of the title track, which became a top five hit in several countries including the US and UK becoming the group's signature song. In late 1985, he appeared on The Facts of Life in the Season 7 episode "Doo-Wah" as himself and performed his single "You Wear it Well" with Lisa Whelchel, Kim Fields, Mindy Cohn, and Nancy McKeon singing backup. In 1986, Eldra left the group and began his solo career with the release of his self-titled debut album, which spawned the hits "Who's Johnny" and "Love Always". Three years passed, however, until DeBarge released his second album, Gemini in 1989. The album had two hits, "Real Love" and "Somebody Loves You". DeBarge's contract with Motown was terminated in 1990, and he signed with Warner Bros. In the meantime, DeBarge was featured on the Quincy Jones single "The Secret Garden", alongside Al B. Sure!, James Ingram, and Barry White, released in 1990.

In 1992, DeBarge released his third album, the Maurice White-produced In the Storm, which featured the Chanté Moore duet "You Know What I Like", which was Moore's first professional recording. Critics noted the album for its Marvin Gaye-styled productions. Eldra later admitted that Gaye was a huge influence on his musical style and once commented that he had initially written "All This Love" as a song he imagined Gaye doing; he even imitated Gaye's ad-libs during his I Want You era near the end. That same year, Eldra had chart success on the R&B charts with a collaboration with Fourplay on their version of Gaye's "After the Dance". DeBarge's next album, 1994's Heart, Mind and Soul, co-produced with Babyface, yielded modest charted singles such as "Slide" and "Where is My Love" which featured Babyface on duet vocals.

While DeBarge continued to collaborate on other artists' projects, including those of his brother Chico and rapper DJ Quik with whom El collaborated on Quik's hit "Hand in Hand", he did not release any more albums between 1994 and 2009. In 2010, he finally emerged from a 16-year delay with the appropriately titled Second Chance, released after a series of comeback performances and appearances, including a well received performance at the 2010 BET Awards. The album yielded two singles, "Second Chance" and the Faith Evans duet "Lay With You", and later resulted in three Grammy Award nominations: Best Male R&B Vocal Performance, Best R&B Song and Best R&B Album. Eldra remains the only member of the DeBarges to have Grammy nominations both outside of the group and in the family.

In 2020, DeBarge made an unexpected return to pop culture after RuPaul referenced his signature mullet on the television show RuPaul's Drag Race. Season 12 contestant Crystal Methyd appeared sporting an identical mullet, much to the enjoyment of RuPaul. On February 4, 2022, DeBarge performed a Tiny Desk Concert for NPR Music at his home, playing keyboards and singing. The concert was part of a celebration of Black History Month.

In 2023, Rolling Stone ranked Eldra at number 137 on its list of the 200 Greatest Singers of All Time. The publication described his voice as "lean and elastic, zooming into falsetto with apparent breath-taking ease." "The ribbons of notes he lets loose during the finish of the group's "All This Love" are like caramel; nearly three decades later, he sang the solo "Second Chance" with such lithe grace that when his voice broke a little at the end, it took the listener with it."

Discography

Solo albums
 El DeBarge (1986)
 Gemini (1989)
 In the Storm (1992)
 Heart, Mind and Soul (1994)
 Second Chance (2010)

with DeBarge
 The DeBarges (1981)
 All This Love (1982)
 In a Special Way (1983)
 Rhythm of the Night (1985)

See also
List of number-one dance hits (United States)
List of artists who reached number one on the US Dance chart

References

External links

1961 births
20th-century African-American male singers
21st-century African-American male singers
African-American male singer-songwriters
American people of French-Canadian descent
American rhythm and blues singers
American rhythm and blues keyboardists
American soul singers
American soul keyboardists
Singers with a three-octave vocal range
DeBarge members
DeBarge family
Living people
American people convicted of drug offenses
Musicians from Grand Rapids, Michigan
Motown artists
Warner Records artists
Interscope Records artists
American tenors
Singers from Detroit
20th-century American pianists
21st-century American keyboardists
21st-century American pianists
American male pianists
African-American pianists
Singer-songwriters from Michigan

El DeBarge


The Biograph Company, also known as the American Mutoscope and Biograph Company, was a motion picture company founded in 1895 and active until 1916. It was the first company in the United States devoted entirely to film production and exhibition, and for two decades was one of the most prolific, releasing over 3000 short films and 12 feature films. During the height of silent film as a medium, Biograph was the most prominent U.S. film studio and one of the most respected and influential studios worldwide, only rivaled by Germany's UFA, Sweden's Svensk Filmindustri and France's Pathé. The company was home to pioneering director D. W. Griffith and such actors as Mary Pickford, Lillian Gish, and Lionel Barrymore.

Founding

The company was started by William Kennedy Dickson, an inventor at Thomas Edison's laboratory who helped pioneer the technology of capturing moving images on film. Dickson left Edison in April 1895, joining with inventors Herman Casler, Henry Marvin and businessman Elias Koopman to incorporate the American Mutoscope Company in New Jersey on December 30, 1895. The firm manufactured the Mutoscope and made flip-card movies for it as a rival to Edison's Kinetoscope for individual "peep shows", making the company Edison's chief competitor in the nickelodeon market. In the summer of 1896 the Biograph projector was released, offering superior image quality to Edison's Vitascope projector. The company soon became a leader in the film industry, with distribution and production subsidiaries around the world, including the British Mutoscope Co. In 1899 it changed its name to the American Mutoscope and Biograph Company, and in 1908 to simply the Biograph Company.

To avoid violating Edison's motion picture patents, Biograph cameras from 1895 to 1902 used a large-format film, measuring  wide, with an image area of , four times that of Edison's 35 mm format. The camera used friction feed instead of Edison's sprocket feed to guide the film to the aperture. The camera itself punched a sprocket hole on each side of the frame as the film was exposed at 30 frames per second.
A patent case victory in March 1902 allowed Biograph and other producers and distributors to use the less expensive 35 mm format without an Edison license, although Biograph did not completely phase out 68 mm production until autumn of 1903.
Biograph offered prints in both formats to exhibitors until 1905, when it discontinued the larger format. Commenting on the 1902 Biograph Company short film The Flying Train, Ashley Swinnerton of the Museum of Modern Art said that the 68 mm format has become "of particular interest to researchers ... because the large image area affords stunning visual clarity and quality."

Biograph films before 1903, were mostly "actualities," documentary film footage of actual persons, places and events, each film usually less than two minutes long, such as the one of the Empire State Express, which premiered on October 12, 1896 in New York City. The occasional narrative film, usually a comedy, was typically shot in one scene, with no editing. Spurred on by competition from Edison and British and European producers, Biograph production from 1903 onward was increasingly dominated by narratives. As the stories became more complex the films became longer, with multiple scenes to tell the story, although an individual scene was still usually presented in one shot without editing. Biograph's production of actualities ended by 1908 in favor of the narrative film.

Studio

The company's first studio was located on the roof of 841 Broadway at 13th St. in Manhattan, known then as the Hackett Carhart Building and today as the Roosevelt Building. The set-up was similar to Thomas Edison's "Black Maria" in West Orange, New Jersey, with the studio itself being mounted on circular tracks to be able to get the best possible sunlight (as of 1988 the foundations of this machinery were still extant). The company moved in 1906 to a converted brownstone mansion at 11 East 14th Street near Union Square, a building that was razed in the 1960s. This was Biograph's first indoor studio, and the first movie studio in the world to rely exclusively on artificial light. Biograph moved again in 1913, as it entered feature-film production, to a new state-of-the-art studio on 175th Street in the Bronx. Among the first projects filmed there was Chocolate Dynamite, which was shot in late August 1913 and was a split-reel comedy short, not a feature-film release.

There was the problem of the underground "duping" business, where people would illegally duplicate a copyrighted movie and then remove the title screen with the company and copyright notice and sell it to theaters. In order to make the theater audience aware that they were watching an American Biograph movie (regardless of whether it was illegally "duped" or not) the AB logo would be prominently placed in random parts of the movie.

Rise of D. W. Griffith

Director D. W. Griffith joined Biograph in 1908 as a writer and actor, but within months became its principal director. In 1908, the company's head director Wallace McCutcheon grew ill, and his son Wallace McCutcheon Jr. took his place but was not able to make a successful film for the company. As a result of these failed productions, studio head Henry Marvin gave the position of head director to Griffith, whose first film was The Adventures of Dollie. Griffith helped establish many of the conventions of narrative film, including cross-cutting to show events occurring simultaneously in different places, the flashback, the fade-in/fade-out, the interposition of closeups within a scene, and a moderated acting style more suitable for film. Although Griffith did not invent these techniques, he made them a regular part of the film vocabulary. His prolific output—often one new film a week—and willingness to experiment in many different genres helped the company become a major commercial success. Many early movie stars were Biograph performers, including Mary Pickford, Lionel Barrymore, Lillian Gish, Dorothy Gish, Robert Harron, Arthur V. Johnson, Florence Auer, Robert G. Vignola, Owen Moore, Alan Hale Sr., Florence Lawrence, Blanche Sweet, Harry Carey, James Kirkwood Sr., Mabel Normand, Henry B. Walthall, Mae Marsh, and Dorothy Davenport. Mack Sennett honed his craft as an actor and director of comedies at Biograph. After debuting at Biograph, Mary Pickford also became a top star at the studio and would soon be known to audiences as "The Biograph Girl".

In January 1910, Griffith and Lee Dougherty with the rest of the Biograph acting company travelled to Los Angeles. While the purpose of the trip was to shoot Ramona in authentic locations, it was also to determine the suitability of the West Coast as a place for a permanent studio. The group set up a small facility at Washington Street and Grand Avenue. After this, Griffith and his players decided to go a little further north to a small village they had heard about that was friendly and had beautiful floral scenery. They decided to travel there and fell in love with this little place called Hollywood. Biograph then made the first film ever in Hollywood called In Old California, a Latino melodrama about the early days of Mexico-owned California. Griffith and the Biograph troupe filmed other short movies at various locations, then traveled back to New York. After the East Coast film community heard about Hollywood, other companies began to migrate there. Biograph's little film launched Hollywood as the future movie capital of the world. It opened a studio at Pico and Georgia streets in downtown Los Angeles (where the Los Angeles Convention Center now stands) in 1911, and sent a film crew to work there each year until 1916.

Griffith left Biograph in October 1913 after finishing Judith of Bethulia, unhappy with the company's resistance to larger budgets, feature film production or giving onscreen credit to him and the cast. With him went many of the Biograph actors, his cameraman Billy Bitzer and his production crew. As a final slight to Griffith, Biograph delayed release of Judith of Bethulia until March 1914, to avoid a profit-sharing arrangement the company had with him.

Decline
In December 1908 Biograph joined Edison in forming the Motion Picture Patents Company in an attempt to control the industry and shut out smaller producers. The "Edison Trust," as it was nicknamed, was made up of Edison, Biograph, Essanay Studios, Kalem Company, George Kleine Productions, Lubin Studios, Georges Méliès, Pathé, Selig Studios and Vitagraph Studios, and dominated distribution through the General Film Co. The Motion Picture Patents Co. and the General Film Co. were found guilty of antitrust violation in October 1915 and dissolved.

Shielded by the Trust, Biograph had been slow to enter feature film production. It contracted with the theatrical firm of Klaw & Erlanger in 1913 to produce movie versions of the latter's plays. Its first released feature, Classmates, came out in February 1914, after 69 other American features had been released in 1912–13. Distribution was hampered by Biograph using a special perforation pattern on the Klaw & Erlanger features that was incompatible with standard projectors, forcing exhibitors to lease specialized equipment from Biograph in order to show the films. With the exodus of the studio's best actors to Griffith, Biograph was unable to develop a marketable star system as the independent companies were doing, and after the Trust's fall, Biograph found itself behind the times. The Biograph Co. released its last new feature-length films in 1915 and its last new short films in 1916. Biograph spent the remainder of the silent era reissuing its old films, and leasing its Bronx studio to other producers.

When the company fell on financial hard times, the Biograph Studio facilities and film laboratory in the Bronx were acquired by one of Biograph Company's creditors, the Empire Trust Company, although some of the ex-Biograph staff were retained to manage the studio and laboratory facilities. Herbert Yates acquired the Biograph Studios facilities and film laboratory in 1928. Biograph Studios facilities and film laboratory were made a subsidiary of his Consolidated Film Industries in 1928. The studio facilities and laboratory burned down in 1980.

In 1939, Iris Barry, founder of the film department at the Museum of Modern Art, acquired 900 cans of film from the Actinograph Corp. Bronx Biograph studio and laboratory facitlies, which was closing its film vault and planning to destroy all the film. One uncompleted film, Lime Kiln Field Day (1913), with an all African American cast, was found among the many cans of film, and shown at MOMA in November 2014.

From 1954 to 1957, Sterling Television Company distributed a package of 100 quarter-hour television shows titled Movie Museum, featuring Biograph, Edison and other early films from the vaults of the Museum of Modern Art and the George Eastman House.

Filmography
 List of Biograph films released in 1909
 List of Biograph films released in 1910

See also

 Biograph Studios
 Biograph Theater
 Cinema of the United States
 History of cinema
 List of film formats
 List of Hollywood movie studios

References

External links

 The Manic Barber from the Southern Methodist University, Central University Libraries, G. William Jones Film and Video Collection
 Arrival of Emigrants [i.e. Immigrants], Ellis Island by Biograph Company, 1906

Articles containing video clips
Film production companies of the United States
1895 establishments in New Jersey

Biograph Company


Crișana Oradea was a football club based in Oradea, Romania. It was founded in 1929 and dissolved in 1954.

History

The club was founded in 1929. The players from the first year of existence were: Putirică, Combi, Aurel, Bulzan, Restea, Slopu, Vanghelu, Blondu, Ștefănescu, Matei, I. Bonațiu, Mureșan, Magău, Budău, Cionca.

In 1930–31, the club won the North League, but was eliminated in the preliminary round of the final tournament by Societatea Gimnastică Sibiu. In 1931–32 it again won the North League but was again eliminated in the preliminary round of the final tournament, this time by Mureșul Târgu Mureș.

In 1932 the club started playing in the First Division, finishing until 1938, in the first half of the championship. Notable players included: Püllöck, I. Budău, I. Bonațiu, Pintea, Bugariu, Frenţiu, I. Baratky, E. Lakatos, C. Deleanu, Țuțuianu, Ad. Bocșa, Al. Torjoc, P. Malița, Pop, Aştilean, Lucaci, Fr. Dvorysák, Țăranu, Ladislau Dallos, Szilágy.

In 1938–39 and 1939–40 the club played in the Second Division. After World War II, it reappeared in the Second Division, merging with CFR, the new name being CFR. In 1947, the two clubs split again, only CFR remaining, but not for long, because in 1954 it was relegated to the regional championship, and with this, it disappeared.

In 1961 the Crișana name reappeared, but only because CA Oradea changed its name, with no connection between them.

Honours

Liga I:
Winners (0): Best finnish: 3rd–4th 1933–34

Liga II:
Winners (1): 1939–40

Association football clubs established in 1929
Association football clubs disestablished in 1947
Defunct football clubs in Romania
Football clubs in Bihor County
Sport in Oradea
Liga I clubs
Liga II clubs
Oradea
1929 establishments in Romania
1947 disestablishments in Romania

Crișana Oradea


The World Wildlife Fund (WWF) identifies terrestrial, marine, freshwater, and ecoregions:
Global 200
List of terrestrial ecoregions (WWF) 867 terrestrial ecoregions.
List of marine ecoregions (WWF), 232 marine ecoregions of the coastal and continental shelf areas.
List of freshwater ecoregions (WWF), 426 freshwater ecoregions.

List of ecoregions (WWF)


9th Sleep is a manga written and illustrated by Makoto Tateno. The manga was first published by Biblos on April 5, 2004, before being re-released by Futabasha on May 12, 2008. It is licensed in North America by Digital Manga Publishing, which released the manga through its imprint, Juné, on 16 December 2009.

Reception
Christopher Nadolski of Mania.com commented that although it seems like a boys love manga, in the end there is "no actual homoerotic payoff for fans of that fare", but feels that the tale "all comes together in a satisfying story of compassion and love." Leroy Douresseaux of Comic Book Bin called the tale "bromance" rather than boys love, and described the plot as the usual Tateno "usual kooky, weird, sci-fi/fantasy scenario", but found it "intriguing" how "she always puts love at the heart of her pulpy nonsense."

References

External links

2004 manga
Digital Manga Publishing titles
Fantasy anime and manga
Futabasha manga
Yaoi anime and manga

9th Sleep


In mathematics and computer science, a random tree is a tree or arborescence that is formed by a stochastic process. Types of random trees include:
Uniform spanning tree, a spanning tree of a given graph in which each different tree is equally likely to be selected
Random minimal spanning tree, spanning trees of a graph formed by choosing random edge weights and using the minimum spanning tree for those weights
Random binary tree, binary trees with a given number of nodes, formed by inserting the nodes in a random order or by selecting all possible trees uniformly at random
Random recursive tree, increasingly labelled trees, which can be generated using a simple stochastic growth rule.
Treap or randomized binary search tree, a data structure that uses random choices to simulate a random binary tree for non-random update sequences
Rapidly exploring random tree, a fractal space-filling pattern used as a data structure for searching high-dimensional spaces
Brownian tree, a fractal tree structure created by diffusion-limited aggregation processes
Random forest, a machine-learning classifier based on choosing random subsets of variables for each tree and using the most frequent tree output as the overall classification
Branching process, a model of a population in which each individual has a random number of children

See also
Lightning tree

External links

Trees (graph theory)
Probabilistic data structures
Random graphs

Random tree


William Bourne (c. 1535–1582) was an English mathematician, innkeeper and former Royal Navy gunner who presented the first design for a navigable  submarine and wrote important navigational manuals. He is often called William Bourne of Gravesend.

In 1574, he produced a popular version of the Martín Cortés de Albacar's Arte de Navegar, entitled A Regiment for the Sea. Bourne was critical of some aspects of the original and produced a manual of more practical use to the seaman. He described how to make observations of the sun and stars, using a cross-staff, and how to plot coastal features from the ship by taking bearings using triangulation.

Life in Gravesend
Before publishing his submarine design, William Bourne was a jurat in Gravesend, England. His name first appears in the first charter of incorporation of Gravesend from June 5, 1562. His name appears once again as a jurat in the second charter of Gravesend, June 5, 1568. During the time of the second charter, the only records of regulations for trading in Gravesend are written in Bourne's handwriting. This would imply that he held an office such as clerk of the market. He also worked as an innkeeper during this time, one of fourteen in the town of Gravesend.

Submarine Design

His design, detailed in his book Inventions or Devises published in 1578, was one of the first recorded plans for an underwater navigation vehicle. He designed an enclosed craft capable of submerging by decreasing the overall volume (rather than flooding chambers as in modern submarines), and being rowed underwater. Bourne described a ship with a wooden frame covered in waterproofed leather, but the description was a general principle rather than a detailed plan. However, the concept of an underwater rowing boat was eventually put into action by the Dutchman Cornelius Drebbel in 1620, and Nathaniel Symons demonstrated a 'sinking boat' in 1729 using the expanding and contracting volume of the boat to submerge.

The submarine was the subject of a modern-day recreation on season 3 of "The Re-Inventors" TV show, episode "Bourne Submarine". The recreation had limited functionality before it sank when water pressure ruptured some membranes on a test descent.

Inventions or Devises

Inventions or Devises, published in 1578, is one of William Bourne's more important works. This book gives many guides and instructional tools for sailors, mostly concerning interactions with other ships. The 21st device listed is the earliest known description of a ship's log and line, which he attributes to Humprey Cole, an officer of the Tower Mint. The 75th device on the list is a description of a night signal or early semaphore system to be used between people on distant ships who had previously decided on a code consisting of a series of lights and fashion of standing.

The 110th entry is what seems to be a type of telescope. The device was said to have been employed by mathematician and surveyor Leonard Digges and Bourne was asked to investigate it by Queen Elizabeth I's chief advisor Lord Burghley. Bourne's is the best description of it, and from his writing it seemed to consist of peering into a large curved mirror that reflected the image produced by a large lens (Bourne noted in his report that the device worked but had a very narrow field of view, making impractical in military applications). This "backwards" reflecting telescope predates the earliest known working telescope by 30 years but its unwieldy nature seems to have kept it from being developed.

Partial list of publications
 An Almanac and Prognostication for Three Years, 1571
 William Bourns booke of artillery, 1572 (draft manuscript)
 Treasure for Travellers, 1572/3
 Art of Shooting in Great Ordnance, 1572/3
 A Regiment for the Sea, 1574 (11 English editions from 1574 to 1631, at least 3 Dutch editions starting in 1594)
 A Booke called the Treasure for Traueilers, 1578 (republished in 1641 as A Mate for Mariners)
 Inventions or Devises. Very Necessary for all Generalles and Captaines, as wel by Sea as by Land, 1578
 The Arte of Shooting in Great Ordinance, 1578, 1587, 1643
 "On Optical Glasses," transcribed manuscript published in Halliwell's Rara Mathematica.

References

External links
Bourne's bibliography, Museum of the History of Science, University of Oxford webpages

16th-century English mathematicians
1530s births
1582 deaths
People from Gravesend, Kent

William Bourne (mathematician)


Norovirus, sometimes referred to as the winter vomiting disease, is the most common cause of gastroenteritis. Infection is characterized by non-bloody diarrhea, vomiting, and stomach pain. Fever or headaches may also occur. Symptoms usually develop 12 to 48 hours after being exposed, and recovery typically occurs within one to three days. Complications are uncommon, but may include dehydration, especially in the young, the old, and those with other health problems.

The virus is usually spread by the fecal–oral route. This may be through contaminated food or water or person-to-person contact. It may also spread via contaminated surfaces or through air from the vomit of an infected person. Risk factors include unsanitary food preparation and sharing close quarters. Diagnosis is generally based on symptoms. Confirmatory testing is not usually available but may be performed by public health agencies during outbreaks.

Prevention involves proper hand washing and disinfection of contaminated surfaces. There is no vaccine or specific treatment for norovirus. Management involves supportive care such as drinking sufficient fluids or intravenous fluids. Oral rehydration solutions are the preferred fluids to drink, although other drinks without caffeine or alcohol can help. Alcohol-based hand sanitizers are not effective against the norovirus, according to the NHS information page on the subject; this is due to norovirus being a non-enveloped virus.

Norovirus results in about 685 million cases of disease and 200,000 deaths globally a year. It is common both in the developed and developing world. Those under the age of five are most often affected, and in this group it results in about 50,000 deaths in the developing world. Norovirus infections occur more commonly during winter months. It often occurs in outbreaks, especially among those living in close quarters. In the United States, it is the cause of about half of all foodborne disease outbreaks. The virus is named after the city of Norwalk, Ohio, US, where an outbreak occurred in 1968.

Signs and symptoms
Norovirus infection is characterized by nausea, vomiting, watery diarrhea, abdominal pain, and in some cases, loss of taste. A person usually develops symptoms of gastroenteritis 12 to 48 hours after being exposed to norovirus. General lethargy, weakness, muscle aches, headaches, and low-grade fevers may occur. The disease is usually self-limiting, and severe illness is rare. Although having norovirus can be unpleasant, it is not usually dangerous, and most who contract it make a full recovery within two to three days.

Norovirus can establish a long-term infection in people who are immunocompromised, such as those with common variable immunodeficiency or with a suppressed immune system after organ transplantation. These infections can be with or without symptoms. In severe cases, persistent infections can lead to norovirus‐associated enteropathy, intestinal villous atrophy, and malabsorption.

Virology

Transmission
Noroviruses are transmitted directly from person to person (62–84% of all reported outbreaks) and indirectly via contaminated water and food. They are extremely contagious, and fewer than twenty virus particles can cause an infection (some research suggests as few as five). Transmission can be aerosolized when those stricken with the illness vomit, and can be aerosolized by a toilet flush when vomit or diarrhea is present; infection can follow eating food or breathing air near an episode of vomiting, even if cleaned up. The viruses continue to be shed after symptoms have subsided and shedding can still be detected many weeks after infection.

Vomiting, in particular, transmits infection effectively and appears to allow airborne transmission. In one incident, a person who vomited spread the infection across a restaurant, suggesting that many unexplained cases of food poisoning may have their source in vomit. In December 1998, 126 people were dining at six tables; one person vomited onto the floor. Staff quickly cleaned up, and people continued eating. Three days later others started falling ill; 52 people reported a range of symptoms, from fever and nausea to vomiting and diarrhea. The cause was not immediately identified. Researchers plotted the seating arrangement: more than 90% of the people at the same table as the sick person later reported becoming ill. There was a direct correlation between the risk of infection of people at other tables and how close they were to the sick person. More than 70% of the diners at an adjacent table fell ill; at a table on the other side of the restaurant, the infection rate was still 25%. The outbreak was attributed to a Norwalk-like virus (norovirus). Other cases of transmission by vomit were later identified.

In one outbreak at an international scout jamboree in the Netherlands, each person with gastroenteritis infected an average of 14 people before increased hygiene measures were put in place. Even after these new measures were enacted, an ill person still infected an average of 2.1 other people. A US Centers for Disease Control and Prevention (CDC) study of 11 outbreaks in New York State lists the suspected mode of transmission as person-to-person in seven outbreaks, foodborne in two, waterborne in one, and one unknown. The source of waterborne outbreaks may include water from municipal supplies, wells, recreational lakes, swimming pools, and ice machines.

Shellfish and salad ingredients are the foods most often implicated in norovirus outbreaks. Ingestion of shellfish that has not been sufficiently heatedunder poses a high risk for norovirus infection. Foods other than shellfish may be contaminated by infected food handlers. Many norovirus outbreaks have been traced to food that was handled by only one infected person.

Between March and August 2017, in Quebec, Canada, there was an outbreak of norovirus that sickened more than 700 people. According to an investigation by Canada's CFIA Food Control Agency, the culprit was frozen raspberries imported from Harbin Gaotai Food Co Ltd, a Chinese supplier, and then Canadian authorities issued a recall on raspberries products from Harbin Gaotai.

According to the CDC, there has been a surge in norovirus cases on thirteen cruise ships in 2023, which marks the highest number of outbreaks since 2012.

Classification
Noroviruses (NoV) are a genetically diverse group of single-stranded positive-sense RNA, non-enveloped viruses belonging to the family Caliciviridae. According to the International Committee on Taxonomy of Viruses, the genus Norovirus has one species, which is called Norwalk virus.

Noroviruses can genetically be classified into at least seven different genogroups (GI, GII, GIII, GIV, GV, GVI, and GVII), which can be further divided into other genetic clusters or genotypes.

Noroviruses commonly isolated in cases of acute gastroenteritis belong to two genogroups: genogroup I (GI) includes Norwalk virus, Desert Shield virus, and Southampton virus; and II (GII), which includes Bristol virus, Lordsdale virus, Toronto virus, Mexico virus, Hawaii virus and Snow Mountain virus.

Most noroviruses that infect humans belong to genogroups GI and GII.
Noroviruses from genogroup II, genotype 4 (abbreviated as GII.4) account for the majority of adult outbreaks of gastroenteritis and often sweep across the globe.

Recent examples include US95/96-US strain, associated with global outbreaks in the mid- to late-1990s; Farmington Hills virus associated with outbreaks in Europe and the United States in 2002 and in 2004; and Hunter virus which was associated with outbreaks in Europe, Japan, and Australasia. In 2006, there was another large increase in NoV infection around the globe. Reports have shown a link between the expression of human histo-blood group antigens (HBGAs) and the susceptibility to norovirus infection. Studies have suggested the capsid of noroviruses may have evolved from selective pressure of human HBGAs. HBGAs are not, however, the receptor or facilitator of norovirus infection. In fact, co-factors such as bile salts may facilitate the infection, making it more intense when introduced during or after the initial infection of the host tissue. Bile salts are produced by the liver in response to eating fatty foods, and they help with the absorption of consumed lipids. It is not yet clear as to at what specific point in the Norovirus replication cycle bile salts facilitate infection: penetration, uncoating, or maintaining capsid stability.

The protein MDA-5 may be the primary immune sensor that detects the presence of noroviruses in the body.  Some people have common variations of the MDA-5 gene that could make them more susceptible to norovirus infection.

Structure

Viruses in Norovirus are non-enveloped, with icosahedral geometries. Capsid diameters vary widely, from 23 to 40 nm in diameter. The larger capsids (38–40 nm) exhibit T=3 symmetry and are composed of 180 VP1 proteins. Small capsids (23 nm) show T=1 symmetry, and are composed of 60 VP1 proteins. The virus particles demonstrate an amorphous surface structure when visualized using electron microscopy.

Genome

Noroviruses contain a linear, non-segmented, positive-sense RNA genome of approximately 7.5 kilobases, encoding a large polyprotein which is cleaved into six smaller non-structural proteins (NS1/2 to NS7) by the viral 3C-like protease (NS6), a major structural protein (VP1) of about 58~60 kDa and a minor capsid protein (VP2).

The most variable region of the viral capsid is the P2 domain, which contains antigen-presenting sites and carbohydrate-receptor binding regions.

Evolution

Groups 1, 2, 3, and 4 last shared a common ancestor in AD 867. The group 2 and group 4 viruses last shared a common ancestor in approximately AD 1443 (95% highest posterior density AD 1336–1542). Several estimates of the evolution rate have been made varying from 8.98 × 10−3 to 2.03 × 10−3 substitutions per site per year.

The estimated mutation rate (1.21 to 1.41  substitutions per site per year) in this virus is high even compared with other RNA viruses.

In addition, a recombination hotspot exists at the ORF1-ORF2 (VP1) junction.

Replication cycle
Viral replication is cytoplasmic. Entry into the host cell is achieved by attachment to host receptors, which mediates endocytosis. Positive-stranded RNA virus transcription is the method of replication. Translation takes place by leaky scanning and RNA termination-reinitiation. Humans and other mammals serve as the natural host. Transmission routes are fecal-oral and contamination.

Pathophysiology
When a person becomes infected with norovirus, the virus replicates within the small intestine. The principal symptom is acute gastroenteritis, characterized by nausea, forceful vomiting, watery diarrhea, and abdominal pain, that develops between 12 and 48 hours after exposure, and lasts for 24–72 hours. Sometimes there is loss of taste, general lethargy, weakness, muscle aches, headache, cough, and/or low-grade fever. The disease is usually self-limiting.

Severe illness is rare; although people are frequently treated at the emergency ward, they are rarely admitted to the hospital. The number of deaths from norovirus in the United States is estimated to be around 570–800 each year, with most of these occurring in the very young, the elderly, and persons with weakened immune systems. Symptoms may become life-threatening in these groups if dehydration or electrolyte imbalance is ignored or left untreated.

Diagnosis
Specific diagnosis of norovirus is routinely made by polymerase chain reaction (PCR) assays or quantitative PCR assays, which give results within a few hours. These assays are very sensitive and can detect as few as 10 virus particles.
Tests such as ELISA that use antibodies against a mixture of norovirus strains are available commercially, but lack specificity and sensitivity.

Prevention
After infection, immunity to the same strain of the virus – the genotype – protects against reinfection for between six months to two years. This immunity does not fully protect against infection with the other diverse genotypes of the virus.

In Canada, norovirus is a notifiable disease. In both the US and the UK it is not notifiable.

Hand washing and disinfectants
Hand washing with soap and water is an effective method for reducing the transmission of norovirus pathogens. Alcohol rubs (≥62% isopropyl alcohol) may be used as an adjunct, but are less effective than hand-washing, as norovirus lacks a lipid viral envelope. Surfaces where norovirus particles may be present can be sanitised with a solution of 1.5% to 7.5% of household bleach in water, or other disinfectants effective against norovirus.

Health care facilities
In healthcare environments, the prevention of nosocomial infections involves routine and terminal cleaning. Nonflammable alcohol vapor in CO2 systems is used in health care environments where medical electronics would be adversely affected by aerosolized chlorine or other caustic compounds.

In 2011, the CDC published a clinical practice guideline addressing strategies for the prevention and control of norovirus gastroenteritis outbreaks in healthcare settings. Based on a systematic review of published scientific studies, the guideline presents 51 specific evidence-based recommendations, which were organized into 12 categories: 1) patient cohorting and isolation precautions, 2) hand hygiene, 3) patient transfer and ward closure, 4) food handlers in healthcare, 5) diagnostics, 6) personal protective equipment, 7) environmental cleaning, 8) staff leave and policy, 9) visitors, 10) education, 11) active case-finding, and 12) communication and notification. The guideline also identifies eight high-priority recommendations and suggests several areas in need of future research.

Vaccine trials
LigoCyte announced in 2007 that it was working on a vaccine and had started phase 1 trials. The company has since been taken over by Takeda Pharmaceutical Company. , a bivalent (NoV GI.1/GII.4) intramuscular vaccine had completed phase 1 trials. In 2020 the phase 2b trials were finished. The vaccine relies on using a virus-like particle that is made of the norovirus capsid proteins in order to mimic the external structure of the virus. Since there is no RNA in this particle, it is incapable of reproducing and cannot cause an infection.

Persistence
The norovirus can survive for long periods outside a human host depending on the surface and temperature conditions:  it can survive for weeks on hard and soft surfaces, and it can survive for months, maybe even years in contaminated still water. A 2006 study found the virus remained on surfaces used for food preparation seven days after contamination.

Detection in food
Routine protocols to detect norovirus in clams and oysters by reverse transcription polymerase chain reaction are being employed by governmental laboratories such as the Food and Drug Administration (FDA) in the US.

Treatment
There is no specific medicine to treat people with norovirus illness. Norovirus infection cannot be treated with antibiotics because it is a virus. Treatments aim to avoid complications by measures such as the management of dehydration caused by fluid loss in vomiting and diarrhea, and to mitigate symptoms using antiemetics and antidiarrheals.

Epidemiology

Norovirus causes about 18% of all cases of acute gastroenteritis worldwide. It is relatively common in developed countries and in low-mortality developing countries (20% and 19% respectively) compared to high-mortality developing countries (14%). Proportionately it causes more illness in people in the community or in hospital outpatients (24% and 20% respectively) as compared with hospital inpatients (17%) in whom other causes are more common.

Age and emergence of new norovirus strains do not appear to affect the proportion of gastroenteritis attributable to norovirus.

Norovirus is a common cause of epidemics of gastroenteritis on cruise ships. The CDC through its Vessel Sanitation Program records and investigates outbreaks of gastrointestinal illness – mostly caused by norovirus – on cruise ships with both a US and foreign itinerary; there were 12 in 2015, and 10 from 1  January to 9  May 2016. An outbreak may affect over 25% of passengers, and a smaller proportion of crew members.

Human genetics
Epidemiological studies have shown that individuals with different ABO(H) (histo-blood group) phenotypes are infected with NoV strains in a genotype-specific manner. GII.4 includes global epidemic strains and binds to more histo-blood group antigens than other genogroups. FUT2 fucosyltransferase transfers a fucose sugar to the end of the ABO(H) precursor in gastrointestinal cells and saliva glands. The ABH-antigen produced is thought to act as a receptor for human norovirus: A non-functional fucosyltransferase FUT2 provides high protection from the most common norovirus strain, GII.4.

Homozygous carriers of any nonsense mutation in the FUT2 gene are called non-secretors, as no ABH-antigen is produced. Approximately 20% of Caucasians are non-secretors due to G428A and C571T nonsense mutations in FUT2 and therefore have strong – although not absolute – protection from the norovirus GII.4. Non-secretors can still produce ABH antigens in erythrocytes, as the precursor is formed by FUT1. Some norovirus genotypes (GI.3) can infect non-secretors.

History
The norovirus was originally named the "Norwalk agent" after Norwalk, Ohio, in the United States, where an outbreak of acute gastroenteritis occurred among children at Bronson Elementary School in November 1968 (although an outbreak had already been discovered in 1936 in Roskilde, Denmark, where it is commonly known as "Roskilde syge" or "Roskilde illness"). In 1972, electron microscopy on stored human stool samples identified a virus, which was given the name "Norwalk virus". Numerous outbreaks with similar symptoms have been reported since. The cloning and sequencing of the Norwalk virus genome showed that these viruses have a genomic organization consistent with viruses belonging to the family Caliciviridae. The name "norovirus" (Norovirus for the genus) was approved by the International Committee on Taxonomy of Viruses (ICTV) in 2002. In 2011, however, a press release and a newsletter were published by ICTV, which strongly encouraged the media, national health authorities, and the scientific community to use the virus name Norwalk virus, rather than the genus name Norovirus when referring to outbreaks of the disease. This was also a public response by ICTV to the request from an individual in Japan to rename the Norovirus genus because of the possibility of negative associations for people in Japan and elsewhere who have the family name "Noro". Before this position of ICTV was made public, ICTV consulted widely with members of the Caliciviridae Study Group and carefully discussed the case.

In addition to "Norwalk agent" and "Norwalk virus", the virus has also been called "Norwalk-like virus", "small, round-structured viruses" (SRSVs), Spencer flu, and "Snow Mountain virus". Common names of the illness caused by noroviruses still in use include "Roskilde illness", "winter vomiting disease", "winter vomiting bug", "viral gastroenteritis", and "acute nonbacterial gastroenteritis".

See also

 Norovirus cis-acting replication element
 Norovirus GII.4 Sydney

References

External links
 Norovirus (vomiting bug) NHS Norovirus infections
 Global network and database noroviruses
 CDC Viral Gastroenteritis FAQs: Center for Disease Control and Prevention of Food Illness Fact Sheet
 "Norovirus in Healthcare Facilities Fact Sheet", CDC, released December 21, 2006
 tips from CDC for cruise vacationers
 Virus Pathogen Database and Analysis Resource (ViPR): Caliciviridae
 3D macromolecular structures of Noroviruses from the EM Data Bank (EMDB)
 Viralzone: Norovirus
 ICTV Report: Caliciviridae

Virus genera
Foodborne illnesses
Healthcare-associated infections
Vomiting
Wikipedia medicine articles ready to translate

Norovirus


Space charge is an interpretation of a collection of electric charges in which excess electric charge is treated as a continuum of charge distributed over a region of space (either a volume or an area) rather than distinct point-like charges. This model typically applies when charge carriers have been emitted from some region of a solid—the cloud of emitted carriers can form a space charge region if they are sufficiently spread out, or the charged atoms or molecules left behind in the solid can form a space charge region.

Space charge effects are most pronounced in dielectric media (including vacuum); in highly conductive media, the charge tends to be rapidly neutralized or screened. The sign of the space charge can be either negative or positive. This situation is perhaps most familiar in the area near a metal object when it is heated to incandescence in a vacuum. This effect was first observed by Thomas Edison in light bulb filaments, where it is sometimes called the Edison effect. Space charge is a significant phenomenon in many vacuum and solid-state electronic devices.

Cause

Physical explanation
When a metal object is placed in a vacuum and is heated to incandescence, the energy is sufficient to cause electrons to "boil" away from the surface atoms and surround the metal object in a cloud of free electrons. This is called thermionic emission. The resulting cloud is negatively charged, and can be attracted to any nearby positively charged object, thus producing an electric current which passes through the vacuum.

Space charge can result from a range of phenomena, but the most important are:

 Combination of the current density and spatially inhomogeneous resistance
 Ionization of species within the dielectric to form heterocharge
 Charge injection from electrodes and from a stress enhancement
 Polarization in structures such as water trees.  "Water tree" is a name given to a tree-like figure appearing in a water-impregnated polymer insulating cable.

It has been suggested that in alternating current (AC) most carriers injected at electrodes during a half of cycle are ejected during the next half cycle, so the net balance of charge on a cycle is practically zero. However, a small fraction of the carriers can be trapped at levels deep enough to retain them when the field is inverted. The amount of charge in AC should increase slower than in direct current (DC) and become observable after longer periods of time.

Hetero and homo charge
Hetero charge means that the polarity of the space charge is opposite to that of neighboring electrode, and homo charge is the reverse situation. Under high voltage application, a hetero charge near the electrode is expected to reduce the breakdown voltage, whereas a homo charge will increase it. After polarity reversal under ac conditions, the homo charge is converted to hetero space charge.

Mathematical explanation
If the near "vacuum" has a pressure of 10−6 mmHg or less, the main vehicle of conduction is electrons. The emission current density (J) from the cathode, as a function of its thermodynamic temperature T, in the absence of space-charge, is given by Richardson's law:

where

 = elementary positive charge (i.e., magnitude of electron charge),
 = electron mass,
 = Boltzmann constant = ,
 = Planck constant = ,
 = work function of the cathode,
 = mean electron reflection coefficient.

The reflection coefficient can be as low as 0.105 but is usually near 0.5. For tungsten, (1 − ř)A0 = , and . At 2500 °C, the emission is 28207 A/m2.

The emission current as given above is many times greater than that normally collected by the electrodes, except in some pulsed valves such as the cavity magnetron. Most of the electrons emitted by the cathode are driven back to it by the repulsion of the cloud of electrons in its neighborhood. This is called the space charge effect. In the limit of large current densities, J is given by the Child–Langmuir equation below, rather than by the thermionic emission equation above.

Occurrence
Space charge is an inherent property of all vacuum tubes. This has at times made life harder or easier for electrical engineers who used tubes in their designs. For example, space charge significantly limited the practical application of triode amplifiers which led to further innovations such as the vacuum tube tetrode.

On the other hand, space charge was useful in some tube applications because it generates a negative EMF within the tube's envelope, which could be used to create a negative bias on the tube's grid. Grid bias could also be achieved by using an applied grid voltage in addition to the control voltage. This could improve the engineer's control and fidelity of amplification. It allowed to construct space charge tubes for car radios that required only 6 or 12 volts anode voltage (typical examples were the 6DR8/EBF83, 6GM8/ECC86, 6DS8/ECH83, 6ES6/EF97 and 6ET6/EF98).

Space charges can also occur within dielectrics. For example, when gas near a high voltage electrode begins to undergo dielectric breakdown, electrical charges are injected into the region near the electrode, forming space charge regions in the surrounding gas. Space charges can also occur within solid or liquid dielectrics that are stressed by high electric fields. Trapped space charges within solid dielectrics are often a contributing factor leading to dielectric failure within high voltage power cables and capacitors.

In semiconductor physics, space charge layers that are depleted of charge carriers are used as a model to explain the rectifying behaviour of p–n junctions and the buildup of a voltage in photovoltaic cells.

Space-charge-limited current

In vacuum (Child's law)

First proposed by Clement D. Child in 1911, Child's law states that the space-charge-limited current (SCLC) in a plane-parallel vacuum diode varies directly as the three-halves power of the anode voltage  and inversely as the square of the distance d separating the cathode and the anode.

For electrons, the current density J (amperes per meter squared) is written:

where  is the anode current and S the surface area of the anode receiving the current;  is the magnitude of the charge of the electron and  is its mass. The equation is also known as the "three-halves-power law" or the Child–Langmuir law. Child originally derived this equation for the case of atomic ions, which have much smaller ratios of their charge to their mass. Irving Langmuir published the application to electron currents in 1913, and extended it to the case of cylindrical cathodes and anodes.

The equation's validity is subject to the following assumptions:
 Electrons travel ballistically between electrodes (i.e., no scattering).
 In the interelectrode region, the space charge of any ions is negligible.
 The electrons have zero velocity at the cathode surface.

The assumption of no scattering (ballistic transport) is what makes the predictions of Child–Langmuir law different from those of Mott–Gurney law. The latter assumes steady-state drift transport and therefore strong scattering.

Child's law was further generalized by Buford R. Conley in 1995 for the case of non-zero velocity at the cathode surface with the following equation:

where  is the initial velocity of the particle. This equation reduces to Child's Law for the special case of  equal to zero.

In recent years, various models of SCLC current have been revised as reported in two review papers.

In semiconductors

In semiconductors and insulating materials, an electric field causes charged particles, electrons, to reach a specific drift velocity that is parallel to the direction of the field. This is different from the behavior of the free charged particles in a vacuum, in which a field accelerates the particle. The proportionality factor between the magnitudes of the drift velocity, , and the electric field, , is called the mobility, :

Drift regime (Mott–Gurney law)

The Child's law behavior of a space-charge-limited current that applies in a vacuum diode doesn't generally apply to a semiconductor/insulator in a single-carrier device, and is replaced by the Mott–Gurney law. For a thin slab of material of thickness , sandwiched between two selective Ohmic contacts, the electric current density, , flowing through the slab is given by:

where  is the voltage that has been applied across the slab and  is the permittivity of the solid. The Mott–Gurney law offers some crucial insight into charge-transport across an intrinsic semiconductor,
namely that one should not expect the drift current to increase linearly with the applied voltage, i.e., from Ohm's law, as one would expect from charge-transport across a metal or highly doped semiconductor. Since the only unknown quantity in the Mott–Gurney law is the charge-carrier mobility, , the equation is commonly used to characterize charge transport in intrinsic semiconductors. Using the Mott–Gurney law for characterizing amorphous semiconductors, along with semiconductors containing defects and/or non-Ohmic contacts, should however be approached with caution as significant deviations both in the magnitude of the current and the power law dependence with respect to the voltage will be observed. In those cases the Mott–Gurney law can not be readily used for characterization, and other equations which can account for defects and/or non-ideal injection should be used instead.

During the derivation of the Mott–Gurney law, one has to make the following assumptions:
 There is only one type of charge carrier present, i.e., only electrons or holes.
 The material has no intrinsic conductivity, but charges are injected into it from one electrode and captured by the other.
 The carrier mobility, , and the permittivity, , are constant throughout the sample.
 The current flow is not limited by traps or energetic disorder.
 The current is not predominantly due to doping.
 The electric field at the charge-injecting electrode is zero, meaning that the current is governed by drift only.

Derivation

Consider a crystal of thickness  carrying a current . Let  be the electric field at a distance  from the surface, and  the number of electrons per unit volume.
Then the current is given has two contributions, one due to drift and the other due to diffusion:

When  is the electrons mobility and  the diffusion coefficient. Laplace's equation gives for the field:

Hence, eliminating , we have:

After integrating, making use of the Einstein relation and neglecting the  term we obtain for the electric field:

where  is a constant. We may neglect the  term because we are supposing that  and .

Since, at , , we have:

It follows that the potential drop across the crystal is:

Making use of () and () we can write  in terms of . For small ,  is small and , so that:

Thus the current increases as the square of . For large ,  and we obtain:

As an application example, the steady-state space-charge-limited current across a piece of intrinsic silicon with a charge-carrier mobility of 1500 cm2/V-s, a relative dielectric constant of 11.9, an area of 10−8 cm2 and a thickness of 10−4 cm can be calculated by an online calculator to be 126.4 μA at 3 V. Note that in order for this calculation to be accurate, one must assume all the points listed above.

In the case where the electron/hole transport is limited by trap states in the form of exponential tails extending from the conduction/valence band edges,

the drift current density is given by the Mark-Helfrich equation,

where  is the elementary charge,  with  being the thermal energy,  is the effective density of states of the charge carrier type in the semiconductor, i.e., either  or , and  is the trap density.

Low voltage regime

In the case where a very small applied bias is applied across the single-carrier device, the current is given by:

Note that the equation describing the current in the low voltage regime follows the same thickness scaling as the Mott–Gurney law, , but increases linearly with the applied voltage.

Saturation regimes

When a very large voltage is applied across the semiconductor, the current can transition into a saturation regime.

In the velocity-saturation regime, this equation takes the following form

Note the different dependence of  on  between the Mott–Gurney law and the equation describing the current in the velocity-saturation regime.  In the ballistic case (assuming no collisions), the Mott–Gurney equation takes the form of the more familiar Child–Langmuir law.

In the charge-carrier saturation regime, the current through the sample is given by,

where  is the effective density of states of the charge carrier type in the semiconductor.

Shot noise
Space charge tends to reduce shot noise. Shot noise results from the random arrivals of discrete charge; the statistical variation in the arrivals produces shot noise. A space charge develops a potential that slows the carriers down. For example, an electron approaching a cloud of other electrons will slow down due to the repulsive force. The slowing carriers also increases the space charge density and resulting potential. In addition, the potential developed by the space charge can reduce the number of carriers emitted. When the space charge limits the current, the random arrivals of the carriers are smoothed out; the reduced variation results in less shot noise.

See also
 Thermionic emission
 Vacuum tube
 Grid leak

References

Electricity
Theories
Microwave technology
Vacuum tubes
Mass spectrometry
Semiconductors

Space charge


The American Crisis is a series of pamphlets (short books) written by Thomas Paine.  They were written during the American Revolutionary War.  They begin with the quote, "these are the times that try men's souls".  The first of the pamphlets was written after a series of losses to the British, and was meant to keep the patriots in the fight.

American Revolutionary War
Pamphlets
1770s books
1780s books

The American Crisis


Jack Snyder is a character on the American soap opera As the World Turns. He was portrayed by actor Michael Park from April 1, 1997 until the final episode on September 17, 2010.

Character history
Jack Snyder came to Oakdale in 1997 to investigate James Stenbeck. After helping to put Stenbeck behind bars, he decided to stay in town and got a job at the Oakdale PD. Jack also got reacquainted with his family and helped his cousin, Holden Snyder, in the search for his daughter. Not long after arriving in town, Jack went with Holden to Montana. There he met his rival, Carly Tenney. Jack and Carly didn't get along at first; in fact they couldn't stand each other. However, despite all their arguing, there was much chemistry between them. Their true feelings for each other became apparent when they investigated arsonist/dirty cop Teague. During the investigation, Jack and Carly got trapped in a cabin where they grew closer and discovered that they had feelings for one another. After returning to Oakdale, Jack wanted to continue the relationship slowly; however Carly was desperate to get married and she dumped Jack to marry Hal Munson.

Reeling from his breakup with Carly, Jack was all set to leave town when he met Julia Lindsey. While helping Julia escape from her controlling fiancé, he fell in love with her. In the meantime, Jack found out the truth about Carly's marriage to Hal—she would inherit a huge trust fund from her sister, Rosanna Cabot, if she married a man and had a baby by him by the time the year was out. Disgusted, Jack told Carly to come clean with Hal or he'd completely walk out of her life. In the end, Hal learned the truth himself and divorced her. Luckily for Carly, she got Dr. John Dixon (who she thought impregnated her with donated sperm) to marry her and, soon after, with the assistance of Jack and Julia, she gave birth to a son, Parker in December 1998. Soon after, Jack's relationship with Julia ended when he learned that she lied to him about killing David Stenbeck, and also because of interference from Carly. Even though Jack tried to avoid Carly and deny his feelings for her, something about her kept pulling him back. Eventually, long buried feelings rose to the surface and they made love. He dumped Carly again, soon after, when he found out that she lied about her son's paternity, Hal not John was the baby's father.

On one occasion, Carly was kidnapped and taken to another country. Jack fought to find her and get her back. She was given a serum that would age her quickly, so by the time she was rescued she had aged quite a bit. But that didn't stop Jack, who held a reluctant Carly in his arms, caring for what was inside more than out. Carly wasn't so embarrassed and let Jack love her. Eventually, Carly was given a reverse serum that brought her looks back to where they were when she left. Jack treated her no different, and she felt safe and secure in his arms.

The night before Jack and Carly were going to get married, they had a huge argument over her relationship with Craig Montgomery. Jack didn't approve of them spending so much time together. Carly was angry when she left, and went to her office and started drinking to calm herself. Mike Kasnoff showed up while Carly was drinking. As they sat there and talked, Carly found comfort in Mike's arms. They made love. The next day, Jack and Carly made up but she never told him about the affair - until she had to. Carly found herself pregnant, but she wasn't sure if it was Mike's baby or Jack's. She went to Montana to get away. Jack followed her, just in time to help with the birth. Carly had a little girl who she named Sage. They renewed their vows and found out later that Sage was Jack's.

Carly's cousin Molly Conlan was in town. She had a mobster chasing her. When he was caught at Jack and Carly's house, Jack came to arrest him. He called for back up, but Molly was so upset at his presence that she insisted that Jack take him out of the house. Jack decided to take him in his car. Carly begged him not to, but he couldn't bear to see Molly upset. On the way to the police department, Jack's car went over the bridge. Jack's body was not in the car. Everyone gave up on the search eventually, but not Carly. She searched until she found Jack. He had amnesia and was married to a woman who was the nurse who took care of him in the hospital. Julia had a son named JJ and they were one big happy family. Carly got Jack to come back to Oakdale, and once he was there, she had him court ordered to live with her instead of Julia. Jack was torn. He finally got his memory back and let Julia down easy. She sought comfort in his cousin, Holden. Carly and Jack were glad to have things back to normal. Tragically, Julia was killed by her ex-husband and JJ was awarded to Jack, since he was the only "real dad" he knew.

Jack and Carly finally divorced in 2006, and after grieving for a while, Carly found herself falling in love with Simon Frasier. The two got into trouble and Jack had to arrest them both. After a struggle, Simon and Carly got away, and Jack took the kids to the farm to stay.

Jack and Katie began dating and he quickly fell for the bubbly blonde. Carly returned to town, putting a wrench in the works and then JJ was kidnapped. Together, Jack and Carly tracked down JJ and brought him home; along the way, Jack began having feelings for Carly again. Nearly unconscious after an explosion, he said, "I love you, Carly," within Katie's hearing (Carly wasn't there). When they returned to Oakdale, Jack decided to put the past behind him and proposed to Katie! Katie accepted and Jack rushed the wedding forward and they were married in a few days.

Just after the wedding, Jack got devastating news: Carly was dying from a brain lesion! He put his life - and his honeymoon - on hold to care for her! Jack was falling for Carly again and asked her to marry him. On the day of their wedding, Carly told him that she was misdiagnosed and had lied about it. He left her at the altar but it was too late to save his relationship with Katie.

He took the kids from Carly and tried to leave her in his past. Janet Ciccone arrived in town and began an affair with Jack. The closer they got, though, the more Jack realized his feelings for Carly weren't in the past. Around this time he learned of Carly's affair with Holden and was livid. Rather than focus on Carly, though, Jack tried to save Parker from a bad relationship with Liberty Ciccone - and a livid Brad! When Brad accused Parker of raping Liberty, Jack and Carly pulled together to clear their son. At Alison and Aaron's wedding, Jack and Carly talked about the past but neither could admit they still had feelings for one another. Janet realized that Jack's feelings weren't in the past and moved out of the farm.

Reception
For portraying Jack Snyder, Michael Park won two Daytime Emmy Awards for Outstanding Lead Actor in a Drama Series in 2010 and 2011 respectively.

References

See also
Jack Snyder and Carly Tenney

As the World Turns characters
Television characters introduced in 1997
Male characters in television
Fictional American police detectives

Jack Snyder (As the World Turns)