The Cybermen are a fictional race of cyborgs principally portrayed in the British science fiction television programme Doctor Who. The Cybermen are a species of space-faring cyborgs who often forcefully and painfully convert human beings (or other similar species) into more Cybermen in order to populate their ranks while also removing their emotions and personalities. They were conceived by writer Kit Pedler (who was also the unofficial scientific advisor to the series) and story editor Gerry Davis, and first appeared in the 1966 Doctor Who serial The Tenth Planet.

The Cybermen have seen many redesigns and costume changes over Doctor Whos long run, as well as a number of varying origin stories. In their first appearance, The Tenth Planet (1966), they are humans from Earth's nearly identical "twin planet" of Mondas who upgraded themselves into cyborgs in a bid for self-preservation. Forty years later, the two-part story, "Rise of the Cybermen" and "The Age of Steel" (2006), depicted Cybermen invented again in a parallel universe London as a business corporation's attempt at upgrading humanity. Doctor Who audio dramas, novels, and comic books have also elaborated on existing origin stories or presented alternatives. The 2017 episode, "The Doctor Falls", explains the different origins as parallel evolution, due to the inevitability of humans and human-like species attempting to upgrade themselves through technology; this perspective resolves continuity differences in the Cybermen's history.

A mainstay of Doctor Who since the 1960s, the Cybermen have also appeared in related programs and spin-off media, including novels, audiobooks, comic books, and video games. Cybermen stories were produced in officially licensed Doctor Who products between 1989 and 2005, when the TV show was off the air, with writers either filling historical gaps or depicting new encounters between them and the Doctor. The species also appeared in the Doctor Who TV spin-off, Torchwood, appearing in the fourth episode, "Cyberwoman" (2006).

Creation

The name "Cyberman" comes from cybernetics, a term used in Norbert Wiener's book Cybernetics or Control and Communication in the Animal and the Machine (MIT Press, 1948). Wiener used the term in reference to the control of complex systems, particularly self-regulating control systems, in the animal world and in mechanical networks. By 1960, doctors were researching surgical or mechanical augmentation of humans and animals to operate machinery in space, leading to the portmanteau "cyborg", for "cybernetic organism".

In the 1960s, "spare-part" surgery began with the development of gigantic heart-lung machines. Public discussion included the possibility of wiring amputees' nerve endings directly into machines. In 1963, Kit Pedler discussed with his wife (who was also a doctor) what would happen if a person had so many prostheses that they could no longer distinguish themselves between man and machine. He got the opportunity to develop this idea when, in 1966, after an appearance on the BBC science programmes Tomorrow's World and Horizon, the BBC hired him to consult on the Doctor Who serial The War Machines (1966). That eventually led to him writing, with Gerry Davis, The Tenth Planet (1966) for Doctor Who.

Pedler, influenced by the logic-driven Treens from the Dan Dare comic strip, originally envisaged the Cybermen as "space monks", but was persuaded by Davis to concentrate on his fears about the direction of spare-part surgery. The Cybermen were originally imagined as human but with plastic and metal prostheses. The Cybermen of The Tenth Planet still have human hands, and their facial structures are visible beneath the masks they wear, but over time they evolved into metallic, more fully mechanized designs.

A variety of specialized forms of Cybermen have been shown, in particular Cyber Leaders and Cyber Controllers, with power to command other Cybermen.

Appearances

Television

Classic series (1963–1996)

The Cybermen first appear in the serial The Tenth Planet in 1966, set in 1986. This serial explains how, millions of years ago, Earth had a twin planet known as Mondas that was knocked out of solar orbit and drifted into deep space. The Mondasians, already far in advance of Earth's technology and fearful for their race's survival, replaced most of their bodies with cybernetic parts. Having eventually removed all emotion from their brains (to maintain their sanity), the natives installed a drive propulsion system to pilot the planet itself through space. As the original race was limited in numbers and were continually being depleted, the Mondasians – now Cybermen – became a race of conquerors who reproduced by forcibly changing other organic beings into Cybermen. The First Doctor (William Hartnell) opposes these Cybermen when they attempt to drain the Earth's energy to make way for Mondas' return to the solar system; in this encounter, Mondas absorbs too much energy from Earth, destroying it and all Cybermen on Earth. The adventure takes its physical toll on the Doctor, forcing him to regenerate for the first time, becoming the Second Doctor (Patrick Troughton).

The Cybermen next appeared later in the same television season in The Moonbase (1967) opposite the Second Doctor. In 2070, the Cybermen attempt to remotely destroy the Earth by affecting its weather patterns with a device called the Gravitron. However, the Gravitron is used against them, hurling them into space. In the following season, The Tomb of the Cybermen saw a 25th Century human expedition discover sarcophagi containing hibernating Cybermen on the planet Telos, where the creatures arise and attack. This episode introduced the cybermats, small mechanical scouts used by the Cybermen, as well as the Cyber Controller. In The Wheel in Space (1968), the Doctor and his crew face off against the Cybermen on a marooned Earth space station in the 21st Century. This episode introduces the Cyber-Planner, an immobile unit which directs the Cybermen. The Cybermen plan to take over the space station, after which their fleet will invade Earth. The Doctor uses an x-ray laser to destroy the Cybermen. In the next season, The Invasion has the Doctor and his companions visit late 20th century England, where he discovers an army of Cybermen are hidden on Earth and working with magnate Tobias Vaughn (Kevin Stoney) to invade Earth. Their invasion is defeated by the Doctor and the military support of the newly formed United Nations Intelligence Taskforce.

The Cybermen did not face the Third Doctor (Jon Pertwee) during his era, but one is shown as part of an exhibit in Carnival of Monsters (1973). The Third Doctor would however face Cybermen in the 20th anniversary special The Five Doctors (1983).

The Fourth Doctor (Tom Baker) is next to encounter a group of Cybermen in Revenge of the Cybermen (1975). These Cybermen are depicted as the wandering remnants of a fallen empire, ravaged by the so-called Cyber-Wars against victorious humanity, which had exploited the Cybermen's weakness to gold. These Cybermen attempt to restore the glory of their race by destroying the gold-rich asteroid Voga.

Cybermen were not seen again until Earthshock (1982), in which the Fifth Doctor (Peter Davison) encounters Cybermen in Earth in the year 2526. The Cybermen plan to destroy the planet with a large bomb while alien dignitaries visit Earth to discuss the ongoing Cyber-Wars. After the Doctor foils this plan, they decide to crash their freighter into the planet to achieve the same result. The freighter is hurled back in time, however, and the Doctor's companion, boy genius Adric (Matthew Waterhouse), is trapped on board as the freighter crashes into prehistoric Earth, killing Adric and triggering the K-T extinction event. The Cybermen appear once more in the Fifth Doctor's era, alongside the four previous Doctors, in The Five Doctors (1983), when they are transported to the Doctor's home planet of Gallifrey by the Time Lord President Borusa (Philip Latham).

Attack of the Cybermen (1985) is set much earlier in the Cyber-Wars than Revenge—during a time when the Cybermen faced defeat following the human invention of the glittergun and the discovery of gold-rich Voga. The Cybermen attempt to use a time machine to avert the destruction of Mondas. Their plan fails and, due to the intervention of the Sixth Doctor (Colin Baker), they also lose their adopted homeworld of Telos to its original inhabitants, the Cryons.

The Cybermen appeared for a final time in the classic series in Silver Nemesis (1988), in which a fleet of Cybermen warships assemble to convert Earth into a new Mondas. A Cybermen scouting party is sent to Earth in search of the legendary Nemesis statue, a Time Lord artefact of immense power, made of the "living metal" validium. The intervention of the Seventh Doctor (Sylvester McCoy) and his companion Ace (Sophie Aldred), however, ensures that the Nemesis destroys the entire cyber-fleet instead.

Between the series' cancellation and its subsequent revival, the Cybermen make one brief appearance, in the 1993 Children in Need special Dimensions in Time, as one of several enemies used by evil Time Lady the Rani (Kate O'Mara) to hunt the Doctor.

Revived series (2005–present)

Doctor Who was revived after a long hiatus by new showrunner Russell T Davies in 2005. By then, development of CGI let script-writers include large numbers of Cybermen or Daleks in stories. In the first series of the revived programme, the Cybermen do not appear except for the inactive head of one, which is seen in a private museum of alien artefacts on Earth in the episode "Dalek". For Series 2 in 2006, Cybermen were reintroduced with a new origin story set in a parallel universe. In the "Rise of the Cybermen" and "The Age of Steel" two-part story, the Tenth Doctor (David Tennant) and his companions, Rose Tyler (Billie Piper) and Mickey Smith (Noel Clarke), crash land in a parallel London where the Cybermen are being created on modern-day Earth. The Cybermen are created by the owner of Cybus Industries, the dying transhumanist mad scientist John Lumic (Roger Lloyd-Pack). Lumic's Cybermen successfully convert much of the world's population by placing their human brains into robotic shells. The Doctor and his friends free London from their control. A human resistance group, the Preachers, then sets about to clean up the remainder of Lumic's factories around the world. The Cybermen reappear in the 2006 two-part finale "Army of Ghosts" and "Doomsday", exploiting a breach between universes to invade the Doctor's Earth. This breach is caused by a transport device belonging to the Daleks, who reveal themselves and trigger all-out war between the two species. The Doctor ultimately re-opens the breach, causing the Cybermen and all but a few Daleks to become trapped inside before it is re-sealed. Cybermen next appear in the 2008 Doctor Who Christmas special "The Next Doctor", emerging in 1851 London after the Daleks damaged the walls of reality in the previous episode, "Journey's End". They attempt to raise a new army on Earth using period technology, but are again foiled by the Doctor.

After Steven Moffat took over the role of executive producer in 2010, Cybermen of essentially the design introduced by Davies continued to appear. No explicit reference is made to their origin, but generally the stylised 'c' (for Cybus Corporation) on their breastplate had been replaced by a plain circle, implying that they were not from the parallel universe. They appear in "The Pandorica Opens" (2010) alongside many of the Doctor's recurring enemies as part of an alliance dedicated to stopping him, arriving in cyber ships in 102 CE. They appear again in "A Good Man Goes to War" (2011), when the Eleventh Doctor's (Matt Smith) companion Rory Williams (Arthur Darvill) demands the location of a secret asteroid base in a quadrant of space which they monitor in the 52nd century. The Doctor destroys a large fleet of their spaceships to indicate their seriousness. In "Closing Time", an ancient slumbering cyber ship is awakened in 2011 Colchester, and the Doctor and his friend Craig Owens (James Corden) work together to repel a Cyberman invasion. This episode also reintroduces cybermats to the series. Neil Gaiman's episode "Nightmare in Silver" (2013) depicts the re-emergence of the Cybermen in the distant future, following what was believed to be their complete eradication by humankind. These redesigned Cybermen have discarded many of their limitations, exhibiting increased speed, rapid upgrading to overcome weaknesses, and the ability to cyberconvert any biological organism into their ranks. The Eleventh Doctor undergoes a partial cyber-conversion, and mentally duels with a Cyber-Planner for control of his body. The emperor of the galaxy (Warwick Davis) orders a planet's destruction to wipe out the Cyberman, but one intact cybermite (new, minuscule cybermat variants) is later seen floating through space. A dead Cyberman head is briefly shown in the UNIT Black Archive in "The Day of the Doctor", and in "The Time of the Doctor" they are among the many species which besiege the planet Trenzalore for centuries. In the latter episode, the Doctor also uses a disembodied Cyberman head, devoid of any remaining organic parts; named "Handles", he serves as the Doctor's personal assistant and confidant for several centuries until his eventual 'death' brings the Doctor to tears.

In the two-part finale of the 2014 series, "Dark Water" and "Death in Heaven", the Twelfth Doctor (Peter Capaldi) learns too late that the Cybermen have formed an alliance with a female incarnation of the Master, Missy (Michelle Gomez), who is converting the stolen bodies of the dead into an army. A cyberconversion process begins on all of Earth's dead. Missy offers the Doctor control of the Cybermen army so they can rule the universe together, but her plan is foiled when Danny Pink (Samuel Anderson), the cyber-converted boyfriend of the Doctor's companion Clara Oswald (Jenna Coleman), resists his programming and destroys himself along with all the other Cybermen. Cybermen are next seen in "Face the Raven" (2015), among the various alien refugees hiding in London, and in series finale "Hell Bent", in which a rusted Cyberman is imprisoned in the Cloisters of Gallifrey. The origin of another group of Cybermen is told in the two-part Series 10 finale "World Enough and Time" and "The Doctor Falls", when a Mondasian colony ship is stuck escaping the gravity of a black hole for many years. The human-like Mondasians, assisted unknowingly by the Master (John Simm), begin upgrading their population to adapt to life aboard the decaying ship. The Doctor reflects on all the societies that have created Cybermen and concludes that the Cybermen is an example of parallel evolution; the Cybermen will always arise and be developed on human-like species across the universe. Ultimately, this encounter with the Cybermen proves brutal: the Doctor's companion Bill Potts (Pearl Mackie) is cyberconverted; two incarnations of the Master (Simm and Gomez) kill one another in a disagreement over standing alongside the Doctor; and the Doctor's companion Nardole (Matt Lucas) is left behind on the ship to look after human colonists, for whom inevitable cyberconversion has been delayed but not averted, though the Doctor manages to destroy most of the Cybermen in a massive explosion. The Doctor, exhausted and wounded to a point of nearing death, awakens in his TARDIS and begins to regenerate. At the same time, the cyberconverted Bill is saved by her old flame Heather who turns her into the same sort of being Heather became after being infected by a sentient liquid.

Cybermen feature heavily in Series 12 (2020). In "Fugitive of the Judoon", experienced companion Captain Jack Harkness (John Barrowman) sends a message to the Thirteenth Doctor (Jodie Whittaker): "do not give the lone Cyberman what it wants". In "The Haunting of Villa Diodati", the Doctor encounters this Cyberman, the sole survivor of the Cyber-Wars, partially-converted Ashad (Patrick O'Kane). She ignores Jack's warning and gives him the Cyberium, the total knowledge of the defeated Cyberman empire, to save human history. This leads to Ashad rejuvenating the Cyber-Empire in season finale "Ascension of the Cybermen" and "The Timeless Children", intending to end all organic life in the universe with a "Death Particle" once he transforms the Cybermen into a purely technological race. However, the Master (Sacha Dhawan) intervenes, promising an alliance only to swiftly betrays Ashad, confiscating the Cyberium and converting the massacred Time Lord civilisation into "CyberMasters" – a new race of infinitely regenerating Cybermen. This army is seemingly defeated by a miniaturised version of the Death Particle. A Cyberman is later seen in the 2021 New Years Special "Revolution of the Daleks" as one of the Doctor's cellmates in a Judoon prison. The CyberMasters and a clone of Ashad return alongside the Master in a daring scheme alongside the Daleks to steal the Doctor's body in "The Power of the Doctor" (2022), narrowly defeated only when the Doctor's companions succeed in bringing her back to life.

In the revival series, some Cybermen who have interacted with the Doctor have been portrayed by actor Paul Kasey.

Spin-offs
The Cybermen have appeared in various spin-off media.

Novels
The Cybermen were also featured in the novel Iceberg by actor David Banks, who played the Cyber Leader in the television series from Earthshock to Silver Nemesis. Banks had previously written, in 1988, Cybermen, a fictional history of the Cybermen which included a "future" design for them. The Missing Adventure Novel Killing Ground also features Cybermen of the type seen in Revenge of the Cybermen. During this novel, the Sixth Doctor's new companion Grant Markham returns to his home planet and learns that a group of Cybermen have hidden on it for centuries, with his robophobia being based around the repressed memory of witnessing a Cyberman kill his mother before he escaped.

In two Virgin Missing Adventures novels by Craig Hinton, the Cybermen become Cyberlords at some point in their history. They are mentioned in passing in Hinton's The Crystal Bucephalus, where the Cyberlord Hegemony is a peaceful future version of the Cybermen who have an empire in the Milky Way; their description was modelled after Banks's designs. In The Quantum Archangel, there are numerous unexplained references to the Cyberlords as an extremely advanced race. At one point, they are referred to as the Time Lords' greatest ally in the Millennium War, though because that war was supposed to have taken place a very long time before the modern era, it is unclear how this bit of Cyberhistory fits in or whether or not they have achieved advanced time travel capabilities. While not explicitly mentioned, Hinton may have adopted this idea from the aborted script for the Five Doctors by Robert Holmes (scriptwriter), which would have had the Cybermen adopting Time Lord DNA to achieve their higher state of being.

The Past Doctor Adventures novel Illegal Alien featured Cybermen and Cybermats in London during the Blitz. Cyber-technology left over from that adventure was subsequently misused in Loving the Alien, written by the same authors. The Fifth Doctor story Warmonger by Terrance Dicks has the Cybermen join the Doctor's alliance against Morbius. The First Doctor story The Time Travellers by Simon Guerrier, set in an alternate reality, has the Cybermen (who are never named) living at the South Pole and trading advanced technology to South Africa. The Eighth Doctor Adventures novel Hope by Mark Clapham features the Silverati, a group of cybernetically enhanced humans heavily reminiscent of the Cybermen, in existence in the very far future as the universe approaches its end, with some evidence suggesting that the Silverati were adapted from remnants of the Cybermen of the present.

Audio dramas
The Cybermen have appeared in several Big Finish audio plays battling the Doctor, the first of which was Sword of Orion (released on CD in 2001 and broadcast on BBC 7 in 2005), where the Eighth Doctor deals with humans and androids engaged in a war who seek Cyber-technology to improve their sides. The 2002 play Spare Parts explored aspects of the Cybermen's origin, revealing that the design was ironically only perfected after their creator, Doctorman Allan, studied the biology of the Fifth Doctor and duplicated a third lobe to the Doctor's brain that controlled his body functions. They were the villains in the company's BBCi webcast Real Time, which was released on purely audio in December 2002. The first instalment of a four-CD series titled Cyberman, which does not feature the Doctor, was released in September 2005. Sword of Orion and the Cyberman series are set around the "Great Orion Cyber-Wars" of the 26th century, when androids rebelled against humanity in the Orion System and both human and android turned to the Cybermen to gain a military advantage. In Sword of Orion, the Cybermen are still entombed on Telos and are mostly forgotten, setting it before Earthshock; by the time of Cyberman, Telos has been destroyed by an asteroid collision, placing that series after Attack of the Cybermen.

The Cybermen appeared in a linked trilogy of plays entitled The Harvest (2004), The Reaping (2006) and The Gathering (2006), where small groups of Cybermen attempt to manipulate humans into setting up conversion factories on Earth. The Bernice Summerfield play The Crystal of Cantus features a former human colony turned into Cybermen, with Irving Braxiatel planning to use them as a private army. A Cyberman tomb also appeared in the Bernice Summerfield play Silver Lining, which came free with Doctor Who Magazine #351. They appear in Human Resources, which Big Finish produced for radio BBC 7 and subsequently released on CD, and sees the Eighth Doctor averting a plan to take control of a new weapons system. The Sixth Doctor joins forces with the Second Doctor's companions Jamie and Zoe to deal with two different Cybermen assaults in Legend of the Cybermen and Last of the Cybermen; Legend sees Zoe made into the new Mistress of the Land of Fiction, bringing in the Sixth Doctor and a fictional version of Jamie to stop the Cybermen conquering the Land, and Last depicts the Sixth swapping places with the Second just as the younger Doctor discovers a Cybermen plot to alter the outcome of the last battle of the Cyber-Wars. In the Fourth Doctor Adventures audio The Fate of Krelos/Return to Telos, the Fourth Doctor, Leela and K9 discover that the Cybermen planted nanobots on Jamie during their past trip to Telos that allow the Cybermen to infect K9 and subsequently use the TARDIS to take over the machinery of the planet Krelos, but the Doctor is able to use a robot drone to go back to his original trip to Telos and prevent Jamie being exposed to the nanites, undoing these events.

In March 2018, the Cybermen had their first encounter with the Third Doctor (this time played by Tim Treloar) in The Tyrants of Logic, one of the stories in Volume 4 of Big Finish's The Third Doctor Adventures series.  In the story, the Doctor and companion Jo Grant (Katy Manning) arrive in the town of Port Anvil on the planet Burnt Salt. They come across a mysterious crate, which the Cybermen set about to reclaim as it contains the "Cyber Leveler," a type of tactician similar to the Cyber Controller. In the ensuing adventure, the Doctor is exposed to "Cyber Smoke," a poisonous gas that prepares a body for cyber conversion.  The Doctor is able to fight off the infection for a time, and develop a cure, which he then uses against the Cybermen, defeating them. The Cybermen battle the Third Doctor and Sarah Jane Smith in the Audio Novel Scourge of the Cybermen. David Banks reprised his role as the Cyber-Leader in Hour of the Cybermen, against the Sixth Doctor and UNIT, and Conversion, which served as a follow-up to Earthshock.

Comics
They have also appeared in the various Doctor Who comic strips, beginning with The Coming of the Cybermen in TV Comic #824-#827. TV Comic cashed in on their frequent presence in the TV series in the late 1960s by featuring them regularly, and they appeared in Flower Power (TVC #832-#835), Cyber-Mole (TVC #842-#845), The Cyber Empire (TVC #850-#853), Eskimo Joe (TVC #903-#906), Masquerade (TVC Holiday Special 1968), The Time Museum (TVC Annual 1969), The Champion (TVC Holiday Special 1969) and Test-Flight (TVC Annual 1970). Their absence from the TV show for most of the 1970s was reflected in a lack of appearances in the strip: they eventually returned in the early 1980s in the Doctor Who Monthly strip Junk-Yard Demon (DWM #58-#59). They made further appearances after the publication was re-titled Doctor Who Magazine: Exodus/Revelation/Genesis (DWM #108-#110), The World Shapers (DWM #127-#129, written by Grant Morrison, which revealed that the Voord were the race that evolved into the Cybermen and that Mondas was previously the planet Marinus), The Good Soldier (DWM #175-#178) and The Flood (DWM #346-#353). In addition, a Cyberman named Kroton, who originally appeared in a couple of Doctor Who Weekly back-up strips called Throwback: The Soul of a Cyberman (DWW #5-#7) and Ship of Fools (DWW #23-#24), was reintroduced in Unnatural Born Killers (DWM #277) and was briefly a companion of the Eighth Doctor in The Company of Thieves (DWM #284-#286) and The Glorious Dead (DWM #287-#296). The Cybermen had their own one-page strip in DWM from issues #215-#238, written by Alan Barnes and drawn by Adrian Salmon.

In 1996, the Radio Times published a Doctor Who comic strip. The first story, entitled Dreadnought, featured the Cybermen attacking a human starship in 2220 and introduced the strip companion Stacy Townsend.

In 2006/7, the Trading Cards magazine Doctor Who - Battles in Time issues 8 - 11 ran a sixteen-page comic strip consisting of four linked stories featuring the Cybermen, written by Steve Cole, drawn by Lee Sullivan and coloured by Alan Craddock.

In the Doctor Who/Star Trek crossover, Assimilation2, the Cybermen join forces with the Borg, forcing the Eleventh Doctor to join forces with the crew of the Enterprise-D to stop them. The Borg and Cybermen have begun to attack and convert worlds without warning, with the apparent 'leader' being a Cyber-Controller with Borg components. The Doctor also recalls a past incident where he helped the crew of the original Enterprise defeat a Cyberman infiltration of a Federation outpost in his fourth incarnation, although it would appear that this is a recent addition to his history as the Eleventh Doctor also remembers not remembering that encounter. The Cybermen attempt to subvert and take over the Borg Collective, forcing the Doctor and the Enterprise to ally with the Borg to stop the Cybermen and restore the Collective to normal.

The Cybermen also feature in the Titan Comics 2016 multi-Doctor event story Supremacy of the Cybermen, which depicts the last Cybermen at the end of the universe forming an alliance with Rassilon- after he was exiled from Gallifrey by the Twelfth Doctor in "Hell Bent"- with the goal of conquering Gallifrey and using Time Lord energy to regenerate the universe into one under Cyber-control. Although Rassilon's insight allows the Cybermen to conquer history and defeat all of the past Doctors, the Twelfth Doctor is able to convince Rassilon to help him after the Cybermen betray Rassilon, the two turning the Cybermens' equipment against them so that the universe is 'regenerated' to a point before the Cybermen conquered Gallifrey, with only the Twelfth Doctor (and possibly Rassilon) remembering these events.

Video games
The 2010 video game Blood of the Cybermen, features Cybermen of the 2006 design without the Cybus Industries chest plate. These Cybermen are unearthed in the Arctic in 2010; their ship is said to have been damaged by a time-storm and crashed 10,000 years earlier. The player plays as the Eleventh Doctor and his companion Amy, who work to defeat the Cybermen. They also appear on Telos in both the android games Doctor Who: The Mazes of Time and Doctor Who and the Dalek.

The Cybermen appear as enemies in Lego Dimensions, and one was added as a playable character in Wave 3.

Physical characteristics

While the Doctor's archenemy, the Daleks, were on the whole unchanged during the original series's 26-season run, the Cybermen were seen to change with almost every encounter. The Cybermen are humanoid, but have been altered until they have few remaining organic parts. They retain living human brains. In their first appearance in the series, the only parts of their bodies that still seemed human were their hands; by their next appearance in The Moonbase (1967), their bodies were entirely covered in their metallic suits, with their hands replaced by three finger claws, but they changed back to regular five-fingered hands in The Invasion (1968). As they are relatively few, the Cybermen tend towards covert activity, scheming from hiding and using human pawns or robots to act in their place until they need to appear. They also seek to increase their numbers by converting others into Cybermen (a process known as "cyber-conversion" or "Cybernisation" in the older episodes and "upgrading" in the newer episodes), an often painful process as body parts are removed and replaced with cybernetic replacements.

It is implied that there are still organic components beneath their suits, meaning they are cyborgs, not robots: in The Tenth Planet, a Cyberman tells a group of humans that "our brains are just like yours", although by the time of Attack of the Cybermen (1985), their brains seem to have been replaced with electronics. Also in this story, two human slave-prisoners of the Cybermen on the planet Telos, named Bates and Stratton, reveal that their organic arms and legs have been removed by the Cybermen and replaced by cyber-substitutes. In Earthshock (1982), the actors' chins were vaguely visible through a clear perspex area on the helmet to suggest some kind of organic matter. In The Tomb of the Cybermen (1967), veins and brains were visible through the domed head of the Cyber-Controller, and similarly, in Attack of the Cybermen (1985) and "The Age of Steel" (2006), the Cyber-Controller's brain is visible through the dome. The first is a Mondas Cyber Controller, and the second involves alternative Earth's John Lumic. However, in Revenge of the Cybermen (1975), the Doctor says they are "total machine creatures".

The audio play Real Time implies that the converted victim's face remains beneath the Cyberman faceplate, although the audio plays, like all non-televised spin-off media, are of uncertain canonicity with regard to the television series. In the 2014's "Death in Heaven", Danny Pink removes the faceplate showing his face underneath. The Virgin New Adventures novel Iceberg by David Banks states that some Cybermen experience rare flashes of emotional memory from the time before they were converted; these flashes are then usually suppressed. The Cybermen in the revived series are usually constructed from human brains bonded to a Cyberman exoskeletal shell with an artificially-grown nervous system threaded throughout ("The Age of Steel"), although direct grafting of cyber-components is another method of conversion ("Cyberwoman"). In "The Pandorica Opens", a Cyberman head is shown to open up, revealing an entire human skull, not just the brain.

Although the Cybermen often claim that they have done away with human emotion, they have exhibited emotions ranging from anger to smug satisfaction in their confrontations with the Doctor. Some Cybermen in the early stories were even given individual names such as "Krang" (however these names only appeared in the cast listings for "The Tenth Planet" and were not spoken on-screen). Some parallel Earth Cybermen did retain some memories of their pre-conversion lives, although their emotional response varied. In "Cyberwoman", the partial conversion led to a degree of insanity in Lisa Hallett, which was retained even after she transferred her brain into a fully human body. In "Doomsday", Yvonne Hartman retains at least some elements of her personality (including her voice being heard over the usual Cyberman voice) to prevent the advance of a group of other Cybermen, and is last seen weeping what appears to be either an oil-like substance or blood. In the same episode, the Cyber-Leader expresses clear frustration at the humans' refusal to surrender, although in a later scene he criticises the Doctor for showing emotion. In "The Age of Steel", the Doctor defeats the Cybermen by shutting down their emotional inhibitors, enabling them to "see" what had become of them. Their realisation of what they had become led them to either simply shut down out of sheer horror, or partially explode. Lastly, when the first Cyber Leader is killed, his head explodes with some white liquid leaking down his body; there are references in that episode to a patented Cybus Industries mixture of chemicals used to preserve the brain. In "Death in Heaven", Danny Pink also retains some of his personality traits, including shock at seeing his reflection and what he's become, but also his love for Clara Oswald. The Doctor turns it on to gain intelligence and reveal that the Cybermen have developed a way to cyber-convert dead human remains. Only then does the Doctor exploit Danny's keeping of his personality traits, even under the inhibitor, to command the Cyber-Army. In "The Doctor Falls", the Doctor's companion Bill retains her complete sense of self and identity, even to the point of not initially seeing herself as a Cyberman, as a result of her experiences resisting mind control and telepathic suggestions in a past adventure. However, Cyberman program does manifest in her bursts of anger and she says her mind cannot hold on forever.

The Virgin Missing Adventures novel Killing Ground, by Steve Lyons suggests that some Cybermen imitate emotions to intimidate and unnerve their victims. The Big Finish Productions audio play Spare Parts (set on Mondas in the early days of Cyber-conversion) suggests that the Cybermen deliberately remove their emotions as part of the conversion process to stifle the physical and emotional trauma of becoming a Cyberman.

This motive behind the removal of emotions is made more explicit in "The Age of Steel", where it is done by an emotional inhibitor. In that episode, deactivating their emotional inhibitors causes the converted Cybermen to realise what they have become, driving them insane and killing them.

Weaknesses

The Cybermen have had a number of weaknesses since their introduction. The most notable weakness of the original Cybermen is the element gold. Their aversion to gold was not mentioned until they try to destroy the planetoid Voga (the so-called "Planet of Gold") in Revenge of the Cybermen (1975). Initially, it was explained that, due to its non-corrodible nature, gold essentially chokes their respiratory systems. For example, the glittergun, a weapon used during the Cyber-Wars in the future, fired gold dust at its targets. However, in later serials, gold appeared to affect them rather as silver affects werewolves, with gold coins or gold-tipped bullets fired at them having the same effect. The revived series's Cybermen have no such weakness, though the tie-in website for the episode mentions it. Cybermen are also efficiently killed when shot with their own guns, or by a Dalek. Other weaknesses from early stories include solvents, gravity based technology, and excessive levels of radiation. In "The Age of Steel", an EMP grenade is shown to disable a Cyberman and shut down its emotional inhibitor. The vulnerability to gold is clearly not present in some early Cyberman types, for example the type seen in the 1968 serial The Invasion were unlikely to possess it, or perhaps more likely the weakness is not known, otherwise the Doctor/UNIT would simply have used it and not needed the elaborate plan involving the assistance of a Russian missile base and the Cybermen's puppet ally, Tobias Vaughn. In "Nightmare in Silver", the Doctor uses gold to slow down though not destroy some circuitry of technologically advanced Cybermen in the distant future. It is unclear precisely how many of the different types, and which types, of Cyberman are vulnerable to gold.

Their armour is often depicted as flexible and resistant to bullets, but can be penetrated by gold arrows and projectiles made of gold. The Cybus Cybermen are bullet-proof and are very resilient, but are not indestructible – they are vulnerable to high explosives, electromagnetic pulses, specialised weaponry and Dalek weapons.

In "The Power of the Doctor" (2022), Tegan Jovanka and Ace fire gold bullets at a group of Cybermen only to be told that they have evolved beyond weakness to gold.

Costumes

For The Tenth Planet, the original Cyberman costumes, including the "handle" shapes on their heads, were designed by Sandra Reid. The masks and one-piece bodystockings were made from jersey fabric, with holes trimmed with vinyl where the Cybermen "eyes" and "mouths" were; the actors' features were darkened to hide their faces. The fabric of the costumes were coloured a faint blue so they could show up on black and white television cameras. Over the top of the stockings, the Cybermen wore polythene suits ribbed with metal wings, along with epaulettes made of metal, and plastic piping. Their boots were short Wellington boots, painted silver. In a 2016 interview, Reid, by then going by the name Alexandra Tynan, described the motivation behind her designs was "I had a planning meeting that I had to be at, and I had to have a design drawing with me. My motivation was the clock on the wall!" Although the script specified the Cybermen should keep their human hands, Reid wanted them to wear gloves. However, Reid mistakenly forgot she said she would make special gloves for the Cybermen until the first day in the studio. Instead, make-up designer Gillian James hastily added silver paint to the actors' human hands. The chest units and "handles" were built by Shawcraft of Uxbridge. The handles were adapted from lorry headlamps, while the chest units used a lot of clear plastic and had battery-powered flashing mechanisms. The handles were intended as the housing for wires that lit up the lamps, but in a test shot the bulb exploded and the idea was dropped. Tynan explained in 2016, "I indicated that there was going to be a chest unit there, but I didn't do any designs for them, because I knew that the units were going to be a props thing."

Producer Innes Lloyd's production team wished to update the Cybermen for The Moonbase and make them look more sophisticated and robotic. Sandra Reid designed new costumes for this serial. These were based on a one-piece silver jumpsuit made from vinyl fabric, and the Cybermen were given gloves with three-fingered hands. Their boots were lace-up army boots painted silver. Fibreglass helmets and chest units made from aluminium were built by freelance prop makers Jack and John Lovell. Silver tape was added around the eye and mouth area for emphasis, and on Reid's instruction, the Lovells attached "hydraulic joints" consisting of tubing from a vacuum cleaner manufacturer and plastic practice golf balls. Costume designer Daphne Dare, consulting with Reid over the phone, took over midway through production of The Moonbase while Reid was recovering from surgery. Eight of these costumes were reused, with slight repainting and additions, for The Tomb of the Cybermen, Reid's final Doctor Who serial, and a new costume was built for the Cyber Controller, with a red-domed cranium built that was intended to light up, but the lighting mechanism failed.

For the filmed inserts in The Wheel in Space, Martin Baugh supervised the creation of the costumes, made from a thinner one-piece material. Junction boxes, linked by steel rods, were used at the joints and near the neck to give the impression of something more technological and functional than was seen in The Moonbase and The Tomb of the Cybermen. The same chest units from before were used, with the lamp at the bottom of the unit. New helmets were cast with simpler handles that extended out further from the head. These introduced a "teardrop" shape to the Cybermen's eyes. An unmodified The Tomb of the Cybermen suit was also used to swell the Cybermen's numbers during the spacewalk scene, and was positioned at the back to hide the difference from the other two costumes. Mid-production, the suits were redesigned again for the more extensive recordings of The Wheel in Space in the studio. Baugh's solution was to spray-paint two padded wet suits to make them look bulkier, with the helmets, junction boxes and rods from the filmed inserts modified or removed to make the actors move more freely. The hands from the earlier Wheel in Space costumes were cut off and used as gloves for the new costumes. The chest units were turned upside down so the lamps, mounted beneath the Cybermen's chins, could be fired as a weapon in a tighter shot.

For The Invasion, costume designer Bobi Bartlett ordered a resculpt of the helmet moulds with more head space for the actors to be done by outside company Trading Post. This included the sculpting of two large "ear muffs". The helmet was made of a light fibreglass. The costumes featured army boots, and now had five-fingered gloves, rather than three. Wetsuits were reused for this serial, and a simpler and sturdier version of the chest units, with the light at the top of the unit as before, was commissioned. At each of the joints there were now domes connected by a set of ribbed rods.

While production notes in Doctor Who: The Complete History claimed that the brief appearance of a Cyberman in Carnival of Monsters consisted of a diving suit from The Invasion, Gavin Rymill in Doctor Who Magazine wrote that this Cyberman was a Cyber Controller costume from The Tomb of the Cybermen. Both sources concurred that the helmet originated from The Invasion, and the back of the helmet was left unfastened.

Prue Handley was the costume designer on Revenge of the Cybermen. The costumes were built by freelance prop company Alister Bowtell, and were again based on wet suits, with rubber tubing along the arms and at the knees and elbow. The chest unit props from The Moonbase returned, and included bits of broken television sets. New, larger fibreglass helmets were made, and the costumes had silver gloves and Wellington boots.

The Earthshock designs by Dinah Collin included a set of Mk 2C RAF flight suits with built-in pipes used to pump cool air around. The Revenge of the Cybermen head was reshaped and recut by Richard Gregory of the freelance company Imagineering to add more details. There was a transparent section in the face through where the actor's moving jaw could be seen. New chest units were made in fibreglass, and they were decorated with ammunition trays. Also worn with the costumes were padded zip-back gloves and Tecnica Moon Boots. For The Five Doctors and Attack of the Cybermen, the jaw area was sprayed silver, and less ostentatious boots were worn. Anushia Nieradzik was the costume designer on Attack of the Cybermen. A specially modified Cyber Controller costume with a tall silver dome on its head was made for Attack of the Cybermen; as with the Controller costume used in The Tomb of the Cybermen, its helmet had no handles. For Silver Nemesis, the same head and chest pieces returned with a dappled plastic jaw and the removal of the ammunition trays. A plainer type of flight suit without built-in pipes was used for the bodies, and cable junction boxes with plastic tubes were added to the limbs for more detail. The costumes had cricket gloves sprayed silver, and Dr. Martens boots.

The redesign of the Cybermen in "Rise of the Cybermen" and "The Age of Steel" was a month-long process involving nearly every part of the design team. The production team decided on an Art Deco approach, and the final design was handed to Neill Gorton's team at Millennium FX, who also built the final costumes. The head was designed to be able to be turned independently from the body; such movement had not been possible in previous helmets. Millennium's Martin Rezard was the lead sculptor of a full-sized clay Cyberman, from which moulds were taken to create over forty fibreglass pieces to make up the head and body of each costume. Powdered aluminium was added to the final layer of the fibreglass, and each component was hand polished until it gleamed. Each of the fibreglass pieces were clipped onto a basic Lycra suit assembled by Jo Glover. The gloves and neck were cast in a soft silver-tinted silicone by Helen Rowe and Alex Whathey. Ten Cyberman costumes were made, including the Cyber Controller, which had a visible brain and pipes connecting him to his life support systems. In "A Good Man Goes to War" the costumes no longer had the Cybus Industries "C" logo introduced in "Rise of the Cybermen".

The sleeker and more elegant design introduced in "Nightmare in Silver" was made by the Millennium FX team from flexible polyurethane rubber, painted to look metallic using a new process originally developed for use in the car industry.

The "Mondasian Cybermen" in "World Enough and Time" and "The Doctor Falls" were created by the Millennium FX team, and were an updated version of Sandra Reid's 1966 design of the Cybermen for The Tenth Planet. The Chest units and helmets and other like attachments were moulded and constructed by Millennium FX. The costumes themselves were built from a silver latex fabric by costume designer Robin Archer. The Cybermen's hands were covered by rubber gloves. Millennium also created the transitional "patients" that evolve into Cybermen from the two-parter. Despite the Tenth Planet Cybermen not having gloves, director Rachel Talalay said that the reason for adding them to the Mondasian Cybermen in the series 10 two-part finale was "partially an issue because of skintone" with Pearl Mackie's Cyberman, but also to "get a scarier feel and something more artificial by putting the gloves on them". She further explained that in The Tenth Planet it was hard to tell if they had skintone gloves or not to justify their addition.

Unlike the Doctor's other foes, the Cybermen costumes have changed substantially in appearance over the years, looking more and more modern, although retaining certain commonalities of design, the most iconic being the "handles" attached to Cybermen heads. Other design elements include their round eyeholes and their chest units.

Aside from these changes, variations in design between rank-and-file Cybermen and their leaders have been seen. In The Wheel in Space and The Invasion (both 1968), the Cyber Director was depicted as an immobile mechanism. The Cyber Leader in "The Next Doctor" sports a transparent brain casing.

Because the Doctor is a time traveller, he meets the Cybermen at various points in their history out of sequence from the order the serials were made. This can be confusing since Cybermen from serials set in "earlier" periods of history can sometimes look more sophisticated than those from "later" periods. Lawrence Miles suggests in his reference work About Time 5 that the anachronistically designed Cybermen of Earthshock and Silver Nemesis are time travellers, like those in Attack of the Cybermen. The Doctor Who Role Playing Game "Cyber Files" worked around the contradiction by stating that in The Tenth Planet, the oldest designs of Cybermen were used for the attack while the later more sophisticated models remained on Mondas.

The Torchwood episode "Cyberwoman" features a partially cyber-converted woman who lacks the outer plating of a fully converted Cyberman. Her body is encased in metal structures but much of her flesh, including her face, is visible. She also has clearly visible metallic breasts, though it is not clear how much of her own flesh has been replaced and how much is merely covered. Another character speculates she could be 40–45% human, and 55–60% Cyberman.

Voice

Early Cybermen had an unsettling, sing-song voice, provided by Roy Skelton, constructed by placing the inflections of words on the wrong syllables. In their first appearance, the effect of this was augmented by having a Cyberman abruptly open his mouth wide and keep it open, without moving his tongue or lips, while the separately recorded voice would be playing, and then shut it quickly when the line was finished. Although the cloth-like masks of the first Cybermen were soon replaced by a full helmet, a similar physical effect involving the mouth "hatch" opening and then shutting when the line was finished was used until The Wheel in Space (1968).

Later, the production team used special effects from its Radiophonic Workshop by adding first a mechanical larynx used by Peter Hawkins, then a vocoder, to modify speech to make it sound more artificial. In later stories of the original series and in the audio plays, two copies of the voice track were sampled and pitch-shifted downwards by differing amounts and layered to produce the effect, sometimes with the addition of a small amount of flanging. From Revenge of the Cybermen to Silver Nemesis (1988) the actors provided the voices themselves, using microphones and transmitters in the chest units.

The voices for the 2006 return of the Cybermen are similar to the buzzing electronic monotone voices of the Cybermen used in The Invasion. They were provided by Nicholas Briggs. As shown in the second series of Doctor Who Confidential, the timbre was created by processing Briggs' voice through a Moog moogerfooger ring modulator. Unusually, in "The Age of Steel", the Cyber-Controller (John Lumic, played by Roger Lloyd-Pack) retains his voice after being upgraded, but it is still electronic. In "Doomsday", a Cyberman which contains the brain of Torchwood Institute director Yvonne Hartman retains a female-sounding though still electronic voice, as does the partially converted Lisa Hallett in "Cyberwoman" when her Cyberman personality is dominant. In an effect reminiscent of the earliest Cybermen's mouths snapping open while speaking, the new Cybermen have a blue light in their "mouths" (or "teeth") which illuminates in synchronisation with their speech.

Since "The Next Doctor" in 2008, the Cybermen have had nasally-sounding electronic voices; this continued all the way until "Closing Time" in 2011. Between the 2013 episode "Nightmare in Silver" and 2017 episode "The Doctor Falls", the Cybermen (continuing to be voiced by Briggs) now have deep, almost growl-like voices. Their mouths retain a blue light-up effect but flicker luminously instead of staying lit as opposed to the 2006 design.

The Patients in "World Enough and Time" (Pre Mondasian Cybermen) communicated through speech synthesis keyboards, similar to those used in hospitals for people unable to talk normally or use their vocal cords. These voices were disturbing in that they almost 'replicated' actual human speech, but with stilted delivery

Variants

Some Cybermen are given titles, being credited as "Cyber Leader" (or variants thereof), "Cyber Lieutenant", "Cyber Scout" or the "Cyber Controller". The Cyber Leader is usually depicted as a Cyberman with black handles.

An immobile computer, referred to as the "Cyber Planner", appears in The Wheel in Space and The Invasion. A Cyber Planner also takes over the Eleventh Doctor's body in "Nightmare in Silver".

The original Controller is seen (and destroyed) in two serials, The Tomb of the Cybermen and Attack of the Cybermen, and in each may or may not be the same consciousness in different bodies; it appears to recognise and remember the Doctor from previous encounters. In the Virgin New Adventures novel Iceberg, the first Cyber Controller is created by implanting a Cyber Director, or Cyber Planner, into the skull of a recently converted Cyberman.

The parallel universe Cyber Controller in "The Age of Steel" uses the brain of John Lumic, the creator of the Cybermen in that parallel reality.

In "Doomsday", a Cyber Leader appears, and when he is destroyed, mention is made of downloading his data files into another Cyberman unit, which is then upgraded to Cyber Leader.

The 2008 Christmas special, "The Next Doctor", featured a new, more agile variant called a Cybershade. The Doctor theorises that it is a more primitive version of a Cyberman, using the brain of a cat, and they physically resemble animals as they cannot speak and walk on all fours. In the same story a "Cyber-King" appears; according to the Doctor, it is a "Dreadnought-class" ship for use in invasions resembling a Cyberman hundreds of feet tall, and contains a Cyber-factory in its chest. It is controlled from within its mouth. Its right arm can be converted into a cannon, and its left into a laser.

"The Time of the Doctor" introduced a unique prototype Cyberman that was made of wood to avoid detection by the Church of the Papal Mainframe and equipped with blowtorches.

After Bill Potts is wounded on the bridge of a Mondasian colony ship, and taken down the ship's lifts to be surgically repaired, she encounters half converted Mondasians referred to only as 'The Patients'. They wore grey surgical robes and their faces were entirely covered with cloth bags, save for a nasal canula that administered fluids and all were hooked up to IV drips. Most remained stationary; reliant on wheelchairs in the "out ward" while some walked the hospital grounds; being prepped for additional surgery and rounding up humans in the city and leading them to the hospital. During the early stages of these experiments (a precursor to cyber-conversion), The Patients were shown to feel the pain caused by this process, with some even begging for death, twisting in their chairs and jabbing at their speech keyboards. They were capable of attacking, following commands (such as restraining Bill) and possessed great strength. They could be incapacitated, though not killed by gunfire.

In "Ascension of the Cybermen" (2020), Cyber Warriors are introduced who are a "Warrior Class" of Cyberman. Their armour is specifically designed in a medieval way, giving the appearance of a medieval warrior. The chest is that of a 2013 Cyberman but with less detail, while their helmets bear a resemblance to the Cybermen from The Invasion. They also have small energy cannons on their wrists. In the following episode "The Timeless Children", the Master creates the "Cyber Masters", a new breed created from Cyberium and Time Lord corpses. These Cybermen, while resembling the Cyber-Warriors, have Time Lord apparel built into their armour, such as their headdresses. These Cybermen were loyal to the Master, and had the ability to regenerate, making them a potentially unstoppable threat. They also appeared in "The Power of the Doctor" with updated designs.

Technology
Cybermen technology is almost completely oriented towards weaponry, apart from their own bodies. When originally seen in The Tenth Planet, they had large energy weapons that attached to their chests. In The Moonbase, the Cybermen had two types of weaponry: an electrical discharge from their hands, which stunned the target, and a type of gun. They also made use of a large laser cannon with which they attempted to attack the base itself.

The hand discharge was also present in The Tomb of the Cybermen, which featured a smaller, hand-held Cyber-weapon shaped like a pistol that was described as an X-ray laser. In The Wheel in Space, the Cybermen could use the discharge to also operate machinery, and had death rays built into their chest units. They displayed the same units in The Invasion as well as carrying large rifles for medium distance combat. In Revenge of the Cybermen and the audio play Real Time, their weapons were built into their helmets. Killing Ground indicates that this type of Cybermen also have more powerful hand weapons. Subsequent appearances have shown them armed almost exclusively with hand-held cyberguns.

The Cybermen have access to weapons of mass destruction known as cobalt bombs, also sometimes as Cyber-bombs, which were banned by the galactic Armageddon Convention (Revenge of the Cybermen). A "Cyber-megatron bomb" was mentioned in The Invasion, supposedly powerful enough to destroy all life on Earth. In Earthshock, the Cybermen also used android drones as part of their plans to invade Earth.

The revived programme Cybermen electrocute their victims by touching them and at first carried no other weaponry. In "Army of Ghosts" and "Doomsday", the Cybermen are equipped with retractable energy weapons housed within their forearms (these were actually first shown in "The Age of Steel", but only very briefly and were not used during that episode), but also use advanced human weapons to battle the Daleks. The arm mounted guns prove effective against humans but are unable to penetrate Dalek shields. Two Cybermen sent to parley with Dalek Thay at the Battle of Canary Wharf shot the Dalek but were promptly exterminated. In the Torchwood episode "Cyberwoman", the partially converted Lisa Hallett used her electrical touch against the Torchwood team, as well as an energy beam fired from her arm which could only stun the part of the body at which it was aimed. In "The Pandorica Opens", the Cybermen again have the wrist-blaster, but also regain the modified human weapons. In "Nightmare in Silver", the Cybermen have the ability to move at a warp-like speed. At this speed they appear as blurry after images. Cyberman had also overcome the weakness of solely being able to convert human-like species; the Doctor had been safe from being in danger of conversion until this point.

The Mondasian Cybermen from The Tenth Planet were updated for the Series 10 Finale. As opposed to shooting from their chest pieces they used their lanterns as weapons. This was in the Novelisation for The Tenth Planet. They also had the ability to emit electricity.

Cybermat

The Cybermen also use smaller, cybernetic creatures called "cybermats" as weapons of attack. In their first appearance in The Tomb of the Cybermen, they resembled oversized metallic silverfish and had segmented bodies with hair-like tactile sensor probes along the base of their heads, which were topped with crystalline eyes. The Second Doctor described them as a "form of metallic life," implying that they may be semi-organic like the Cybermen, and that they too attack by feeding off brain waves. They were defeated using electricity.

The second model of Cybermat seen in The Wheel in Space was used for sabotage, able to tune in on human brainwaves. They were carried to the "Wheel" in small but high-density sacs that sank through the hull of the space station, causing drops in air pressure. These Cybermats had solid photoreceptors for eyes instead of crystals. The Second Doctor used an audio frequency to jam them, causing them to spin, crash and disintegrate.

The third model, seen in Revenge of the Cybermen, was a much larger, snake-like cybermat that could be remotely controlled and could inject poison into its victims. It had no visible eyes or other features, and was as vulnerable to gold dust as the Cybermen were.

The original model was later mentioned in a conversation between the Doctor and his double during The Rebel Flesh, reaffirming that that model of Cybermat killed by feeding on brainwaves.

The fourth model of cybermat appears for the first time in the revived series in the 2011 episode "Closing Time", where it is shown to have an organic mouth full of sharp teeth, and transmits power to a crashed cyber-ship.

In the audio play Spare Parts, "mats" are cybernetically augmented creatures, sometimes kept as pets. Cybermats of a different design are used for surveillance by Mondas' Central Committee. The creatures occasionally go wild, chewing on power sources, and must be rounded up by a "mat-catcher." In the Past Doctor Adventures novel Illegal Alien by Mike Tucker and Robert Perry, set in the 1940s, the Cybermen create cybermats by cyber-converting local animals like cats or birds, possibly because of lack of technological resources.

In the Bernice Summerfield audio adventure The Crystal of Cantus, a Cyberman reveals that the organs of children who are too small to be fully cyber-converted are used in the creation of cybermats.

The cybermats appeared in the video game "Blood of the Cybermen" where instead of killing, they turned individuals into cyberslaves. The slaves have mostly human bodies, but have Cyberman heads and arms. The Cybermen see the cyberslaves as inferior, and delete them once they have served their purpose.

An upgraded form of cybermats appeared in "Nightmare in Silver". They were incredibly small mechanical insects that were more versatile and were able to partially convert other lifeforms into Cybermen. They were referred to as cybermites.

See also
 Borg (Star Trek)
 Cylon (Battlestar Galactica)

References

Sources

External links

 Designer Alexandra Tynan discusses the creation of the cybermen on the Boxcutters podcast

Doctor Who races
Brain–computer interfacing in fiction
Fictional extraterrestrial cyborgs
Fictional elements introduced in 1966
Fictional characters who can move at superhuman speeds
Fictional kidnappers
Fictional characters with superhuman strength
Fictional warrior races
Human-derived fictional species
Torchwood characters

de:Liste der Rassen und Einzelwesen aus Doctor Who#Cybermen
Fictional cyborgs

Cyberman


Vinhais (; ) is a municipality in the district of Bragança, northern Portugal. The population in 2011 was 9,066, in an area of 694.76 km2.

The present mayor is Américo Afonso Pereira, elected by the Socialist Party. The municipal holiday is May 20.

Parishes

The municipality is composed of 26 parishes:

 Agrochão
 Candedo
 Celas
 Curopos e Vale de Janeiro
 Edral
 Edrosa
 Ervedoa
 Moimenta e Montouto
 Nunes e Ousilhão
 Paçó
 Penhas Juntas
 Quirás e Pinheiro Novo
 Rebordelo
 Santalha
 Sobreiró de Baixo e Alvaredos
 Soeira, Fresulfe e Mofreita
 Travanca e Santa Cruz
 Tuizelo
 Vale das Fontes
 Vila Boa de Ousilhão
 Vila Verde
 Vilar de Lomba e São Jomil
 Vilar de Ossos
 Vilar de Peregrinos
 Vilar Seco de Lomba
 Vinhais

Geography

The northern boundary of the municipality extends to the border with Spain, 23 km away.

It is perched on the slopes of the Coroa mountains at an altitude of approximately 600 meters, protected from the cold winds of the north by the Ciradelha mountain, where in remote times there was a Luso-Roman castro. On the south side is the Tuela River valley. There are three other rivers in the concelho: the Rabaçal, the Mente, and the Baceiro. They are relatively unpolluted and provide fish for locals and tourists. The Baceiro has a trout hatchery which is deactivated but will be reopened soon.

The Castle of Vinhais is a protected public interest.

History

This ancient town, older than the founding of Portugal, owes its name to the abundance of vineyards that covered the slopes and produced excellent wine. Today the production of wine has almost disappeared.

In the time of the Romans there was a settlement called Veniatia, through which passed the road that linked Braga to Astorga. Suebi, Visigoths, Vandals, and Moors all were present in the region.  One of the first kings of Portugal, Sancho II had a castle and walls built, around which grew a small town soon to be called Vinhaes. This town was nicknamed Rich Town, because of the abundance of its wine, linen, silk, and wool.

Several times occupied by the Castilians it became part of Portugal again in 1403. In 1659 a Spanish general invaded the region and besieged Vinhais with 1,700 men. The castle resisted and the enemy retreated across the border, burning all the houses outside the walls as well as all the villages they passed through.

After the fall of the monarchy in 1910, the Royalist rebel Paiva Couceiro entered Vinhais and attacked the Republican forces, defeating them and sending them in retreat to Chaves

Paiva Couceiro's entry into Vinhais was received with joy because this town was still pro-monarchy.  Soon, the Provisional Government of the Republic sent 400 soldiers to attack the rebels. After some violent skirmishes the rebels were defeated and forced to surrender. See Royalist attack on Chaves

Today, Vinhais is a small, rather isolated municipality, with an aging rural population. Without industry and with a diminishing population, it relies on tourism, an annual fair specializing in smoked meats, and some agriculture, especially chestnut growing.

The northern part of Vinhais is also part of the Montesinho Natural Park, with a significant interest on the rural and agricultural kind of life and wild life preservation. Among the protected species are the Iberian Wolf, Roe Deer, Wild Boar, Iberian Lynx, Common Genet, Red Fox and European Otter. To accomplish a better understanding of the wild life, there is now a Biological Park (Parque Biológico de Vinhais) in the Ciradelha Mountain.

References

External links
Municipality official government
Vinhais

Towns in Portugal
Municipalities of Bragança District

Vinhais


Società Sportiva Dilettantistica Acireale Calcio 1946 is an Italian association football club, based in Acireale, a city of 57,000 inhabitants 18 km away from Catania in Sicily. The club currently plays in Serie D, although they have played for two seasons in Serie B.

History

Foundation
The club's roots can be traced back to a previous club in the city, from whose ashes the current incarnation rose from; the older club in the city played between 1928 and 1935.

The club was founded in 1946 as A.C. Acireale, making its debut in Serie C.

The team reached its culmination in 1992/1993 when, after a long period played in Serie C1, C2 and D, the team, coached by Giuseppe Papadopulo, surprisingly gained its first promotion to Serie B. During its first Serie B season in 1993/1994, Acireale avoided relegation after having won a play-off against Pisa Calcio on penalties. But, in its next season, Acireale was not able to repeat their feat, and were relegated to Serie C1. Acireale successively played consecutively four season in Serie C2, a period which ended in 2003 after being promoted on playoffs. However, after a disappointing Serie C1 season in 2005/2006, ended with a relegation to Serie C2, Acireale dropped because of financial troubles.

The refoundation

A new property registered the club as Acireale Calcio to the Promozione regional league, the 7th level in the Italian football league system. In its first Promozione season, the club readily won its league round being thus promoted to Eccellenza. The club was renamed to the current denomination in August 2007, and will take part to the Sicilian Group B of Eccellenza in 2007–2008, obtaining the promotion in the season 2009–10 to Serie D.

Notable former managers
 Walter Mazzarri
 Giuseppe Papadopulo
 Francesco Scoglio

External links

Official homepage

Football clubs in Italy
Football clubs in Sicily
Association football clubs established in 1946
Serie B clubs
Serie C clubs
1946 establishments in Italy
2006 establishments in Italy
2014 establishments in Italy
Serie D clubs
Phoenix clubs (association football)

ASD Città di Acireale 1946


Fermium (symbol Fm) is a chemical element. It has an atomic number of 100, which makes it at position 100 at the periodic table. Fermium cannot be found in nature; it has to be made.  Scientists can create it by combining plutonium with neutrons at very high speeds and temperatures.  It is named after Enrico Fermi.

History
Albert Ghiorso and other scientists at the University of California, Berkeley first discovered fermium.  They found the element in the fallout from the explosion of the first successful hydrogen bomb test.  This test was on November 1, 1952.  In the fallout, scientists also discovered another new element, Einsteinium.  Because of the Cold War, the US military did not allow the scientists to publish their results in a scientific journal.  However, they conducted other studies and published their research in 1954.  The studies of nuclear fallout were declassified and published in 1955.

A group in the Nobel Institute for Physics in Stockholm also discovered isotopes of this element before the research of the Berkeley scientists was published.  However, most agree that the Berkeley scientists were the first to discover fermium.

Actinides
Synthetic elements

Fermium


William Copeland Dodge (September 6, 1880 – August 4, 1973) was an American lawyer and Democratic politician in New York City, New York, United States. He was an associate of the Tammany Hall political organization in the city.

Early life
William Copeland Dodge was born on September 6, 1880 Manchester, New Hampshire, to Arthur Pillsbury Dodge (1849–1915) and Elizabeth Ann Day (1854–1927). The family moved to Chicago in 1891, and then to New York City in 1897. Dodge graduated from Stevens Institute of Technology, and from New York University School of Law. He was admitted to the bar in 1906. He later entered politics as a member of Tammany Hall; his patron was James Joseph Hines.

Political career
He was elected in 1918 as a member of the New York State Senate (20th D.), serving in 1919 and 1920. As a State Senator he was active in urging an investigation of William Hamilton Anderson of the New York Anti-Saloon League.

In December 1924, he was appointed by D.A. Joab H. Banton as an Assistant D.A. of New York County. In 1927, he was appointed by Mayor Jimmy Walker as a city magistrate to fill the vacancy caused by the retirement of Norman J. Marsh.

In November 1933, Dodge was elected New York County District Attorney with promises to clean up the office by eliminating leaks. Leaks in the prosecution of racketeering cases had earlier led to intimidation of witnesses, thereby allowing more notable criminals to escape prosecution. His plan was to provide to the grand jury only the minimum information required to receive an indictment.

Runaway grand jury
In 1934, a grand jury was convened to investigate gambling in the city. The grand jury sat for 11 months, but resulted in only a few prosecutions. Charges were made that politicians were regularly fixing gambling cases.  A memo by Mayor Fiorello La Guardia's office showed that between February 1 and September 30, 1934, 91% of the gambling cases brought by police never even came to trial, and of those that did come to trial, one third ended in fines usually under $50.

On March 4, 1935, Dodge convened a grand jury to investigate gambling, and in particular the actions of Dutch Schultz. The grand jury spent its time with other cases and information on witnesses was being leaked. Grand jurors complained that only junior investigators were assigned to them. Gambling kingpins were quoted in the newspapers boasting that they would never be indicted.

The jurors complained in open court about the problems on May 7, 1935, which was widely reported by the city newspapers. On May 22, 1935, Dodge agreed to appoint a special prosecutor from a list prepared by the New York County Lawyers Association. He balked at appointing any of the Republicans on the list because he considered them political opponents of Democrats. Instead, he selected H. H. Corbin, a compromise candidate proposed by former Republican Governor Nathan L. Miller, despite objections by the grand jurors. When the juror objections were made public, Corbin refused the appointment. The "runaway" grand jury disbanded in June, still complaining that the cases were not adequately being investigated.

On June 24, 1935, Governor Herbert H. Lehman said a new investigation would occur. Of the four names that were put forth, only Thomas E. Dewey accepted the task; he brought a series of successful prosecutions.

Dodge chose not to run for re-election in 1937, and he left office at the end of his term in December 1937. Republican Thomas Dewey was elected in November to succeed him as New York County Attorney.

It remains unclear whether Dodge criminally profited from the events. It was revealed that gangster Dutch Schultz paid $15,000 for his election. His patron Hines was quoted in his own trial as saying Dodge was "stupid, respectable, and my man." Dodge was never formally charged with any wrongdoing.

Death and legacy
Dodge died on August 4, 1973, in Lee, Florida.

Dodge kept scrapbooks throughout his life documenting his career and personal interests. These scrapbooks are housed in the Special Collections of the Lloyd Sealy Library at John Jay College of Criminal Justice. Included in the Dodge Collection are materials related to his campaign and clippings from New York City newspapers that documented local crime at the time.

References

Further reading
Arthur Pillsbury Dodge at Bahá'í Encyclopedia
Fighting Organized Crime: Politics, Justice, and the Legacy of Thomas E. Dewey by Mary M. Stolberg (Northeastern, 1995,  ; page 50)
Kill the Dutchman! - The Story of Dutch Schultz by Paul Sann
Little Flower: The Life and Times of Fiorello La Guardia by Lawrence Elliott (Morrow, 1983)
ANTI-SALOON LEAGUE INQUIRY CALLED FOR in NYT on March 4, 1919
Boy Hunter Uses His Belt as Tourniquet; Saves Life of Chum Shot on Hunting Trip, his son's shooting accident, in NYT on October 26, 1925
DODGE LONG PROUD OF TAMMANY TIES in NYT on August 3, 1938 (subscription required)
William C. Dodge Scrapbooks (1933-1937) collection (not yet digitized) at Lloyd Sealy Library Special Collections, John Jay College of Criminal Justice, New York City

1880 births
1973 deaths
Politicians from Manchester, New Hampshire
Lawyers from Chicago
New York County District Attorneys
Stevens Institute of Technology alumni
New York University School of Law alumni
Democratic Party New York (state) state senators
20th-century American politicians
20th-century American lawyers

William C. Dodge


Andhrímnir is the chef of the gods in Norse mythology. He is the god that killed the mighty boar Sæhrímnir. He cooks Sæhrímnir in his cauldron named Eldhrímnir. The cooked beast is then fed to the gods and fallen warriors in Valhalla. At night, the boar comes back to life so Andhrímnir can kill him and cook him again. This way, the gods and fallen warriors eat well until Ragnarok.

Norse mythology

Andhrímnir


Edgar Karl Alfons Ende (23 February 1901 – 27 December 1965) was a German surrealist painter and father of the children's novelist Michael Ende.

Ende attended the Altona School of Arts and Crafts from 1916 to 1920.  In 1922 he married Gertrude Strunck, but divorced four years later. He remarried in 1929, the same year his son Michael was born.  In the 1930s Ende's Surrealist paintings began to attract considerable critical attention, but were then condemned as degenerate by the Nazi government. Beginning in 1936 the Nazis forbade him to continue to paint or exhibit his work. In 1940 he was conscripted into the Luftwaffe as an operator of anti-aircraft artillery.

The majority of his paintings were destroyed by a bomb raid on Munich in 1944, making his surviving pre-war work extremely rare.  In 1951, Ende met the recognized founder of Surrealism, André Breton, who admired his work and declared him an official Surrealist. He continued to paint surrealist works until his death in 1965 from a myocardial infarction.

Ende's paintings are thought to have had a significant influence on his son's writing. This is inferred in the scenes depicting the surreal dream-paintings from Yor's Minroud in Die Unendliche Geschichte (The Neverending Story), and is made explicit in Michael Ende's book Der Spiegel im Spiegel (The mirror in the mirror), a collection of short stories based on (and printed alongside) Edgar Ende's surrealist works.

See also
 List of German painters

References

External links
 www.edgarende.de - Extensive information, including pictures of his work (German and English).

1901 births
1965 deaths
20th-century German painters
20th-century German male artists
German male painters
German surrealist artists

Edgar Ende


Lientur was the Mapuche toqui from 1618 to 1625.  He was the successor to Loncothegua.  Lientur with his vice toqui Levipillan was famed for his rapid malóns or raids.  Because of his ability to slip back and forth over the Spanish border between its fortresses and patrols and raid deep into Spanish territory north of the Bio-Bio River without losses he was called the Wizard by the Spanish.

In 1625 his successor Butapichón was elected when he resigned his office when he felt himself to be too old and tired to continue as before.  However a cacique named Lientur continued to lead troops in the field.  He was present leading troops at the Battle of Las Cangrejeras.  A cacique of that name also participated in the Parliament of Quillín in 1641.

References

Sources
 Diego de Rosales, "Historia General del Reino de Chile", Flandes Indiano, 3 tomos. Valparaíso 1877-1878.
  Historia general de el Reyno de Chile: Flandes Indiano Vol. 2
  Historia general de el Reyno de Chile: Flandes Indiano Vol. 3
 Vicente Carvallo y Goyeneche,  Descripcion histórico-jeográfica del Reino de Chile TOMO I, precedida de una biografia del autor por don Miguel L. Amunátegui, Coleccion de historiadores de Chile y documentos relativos a la historia nacional TOMO VIII, SANTIAGO DE CHILE: IMPRENTA DE LA LIBRERÍA DEL MERCURIO de A. y M. Echeverria, Morando Núm. 38. 1878  (History of Chile 1542-1788)
  Juan Ignatius Molina, The Geographical, Natural, and Civil History of Chili, Longman, Hurst, Rees, and Orme, London, 1809
  José Ignacio Víctor Eyzaguirre, Historia eclesiastica: Politica y literaria de Chile, IMPRENTA DEL COMERCIO, VALPARAISO, June 1830 List of Toquis, pg. 498-500.
  Anson Uriel Hancock, A History of Chile, Chicago, C. H. Sergel and Company, 1893

17th-century Mapuche people
People of the Arauco War
Indigenous leaders of the Americas
Toquis

Lientur


"Lucky Star" is the fourth single from Madonna's hit record Madonna. The song was first released in United Kingdom in 1983. It was originally produced by Reggie Lucas, although during recording Madonna was not happy with the final results of the song. According to her, Lucas used too many instruments and did not consider her ideas for the song. She called her boyfriend (at the time), John Benitez, to remix her songs. When the "Lucky Star" video was released in 1984, her style and mannerisms became a fashion trend among younger people.

1984 songs
Madonna (entertainer) songs

Lucky Star (Madonna song)


The Queen's Gambit Declined is a chess opening which starts with 1.d4 d5 2.c4 e6. It is an old opening, and one of the most important. It is often used in top-class play. In this opening, called QGD for short, the struggle for the centre is the strategy of both players. Unlike the Queen's Gambit Accepted, Black keeps his pawn on d5 protected. A simple example:

1.d4 d5
2.c4 e6
3.Nc3 Nf6
4.Bg5 Be7
5.e3 0-0
6.Nf3 c6
7.cxd5 exd5
8.Bd3 Nbd7 (Black could play 8...Ne4 here)
9.0-0 h6
10.Bh4

Here White has more space, and Black has to decide how to develop his pieces. It is easier to play the white pieces in this kind of position. However, overall, black players do as well with this defence as with most others. Best for Black in this position is 10...Ne4 or 10...Re8.

Chess openings

Queen's Gambit Declined


A corner kick is a kick awarded to the team for their opportunity to shoot at goal in soccer. It happens when the ball has come off a footballer at his or her own goal. There are two corner posts at each end of the ground, so two for each team depending where the ball is kicked out.

Football (soccer) terminology

Corner kick


The Véhicule Blindé Léger or VBL (light armoured vehicle) is a four-wheel drive reconnaissance light military vehicle. It has been used by the French army since 1990. More than 25 foreign countries used it, including Gabon, Qatar, and Serbia. The US Army used it as M11 for hazardous material reconnaissance. Russia bought 500 of them in November 2012.

The vehicle is designed and built in France by Panhard.

Military of France
Military transport

Véhicule Blindé Léger


The Centre for Renewable Energy Systems Technology (CREST) is a research centre into renewable energy based in the Department of Mechanical, Electrical and Manufacturing Engineering, Loughborough University in England.

Profile
Established in 1993, it is recognised internationally as a centre of excellence in its field particularly in photovoltaic systems, materials and devices, wind power and integration of renewable energy into electricity grids. About fifty researchers, academics and associated staff are involved with CREST's work.

The MSc course in Renewable Energy Systems Technology, developed at CREST, is one of the longest established renewable energy masters courses globally.  It is producing a stream of graduates who are working internationally in all aspects of the renewables industry. This course can be studied full-time or part-time distance learning. As an advanced technology course, the modules in the CREST MSc include biomass, wind, solar, water/marine and electrical integration. There is a strong emphasis on electrical generation throughout.

History
The centre was initially set up through the funding of Professor Tony Marmont of Beacon Energy, who remains a mentor and advisory committee member. Other advisory members include Sir Jonathon Porritt and Dr Andrew Garrad of Garrad Hassan & Partners Ltd. Professor Phil Eames is the director of CREST and Leon Freris is a visiting professor. Professor Freris, and Dr David Sharpe, a leading British wind turbine aerodynamicist who also worked at the centre, were founding members of the British Wind Energy Association (now RenewableUK). David Sharpe has since become known for his work as the inventor of the Aerogenerator.

Associations
The Masters course is one of only sixteen programmes in the UK admitted to the Panasonic Fellowship programme  (run by the Royal Academy of Engineering). The Panasonic Fellowship programme is aimed at recent graduates who wish to embark on a full-time master's degree course in environmental studies or sustainable development.

CREST is a participating university in the EUREC European Masters Program in Renewable Energy, an initiative supported by the European Commission to expand the European renewable energy industry.

The group is located in the Holywell Park area of the Loughborough campus, adjacent to the offices of the Energies Technology Institute (ETI).

References

External links
 Official site of CREST
 Official site of Department of Mechanical, Electrical and Manufacturing Engineering
 European Masters in Renewable Energy

Loughborough University
Research institutes in Leicestershire
Renewable energy organizations
Organisations based in Leicestershire
Organizations established in 1993
Buildings and structures in Leicestershire
Renewable energy in England
1993 establishments in England


Dina sains, rékayasa, industri jeung statistik, akurasi nyaéta tingkatkacocogan ukuran atawa lobana itungan kana nilai sabenerna (nilai nu bener). Akurasi pakait raket jeung presisi, disebut ogé bisa dijieun deui atawa diulang deui, tingkat nu dina ukuran atawa itungan saterusna nembongkeun hasil nu sarua atawa ampir sarua. Hasil itungan atawa ukuran bisa akurat tapi teu présisi; présisi tapi teu akurat; atawa teu présisi jeung teu akurat. Hiji hasil disebut valid lamun akurat jeung presisi. Watesan nu pakait dina survey nyaéta kasalahan (variabel acak dina panalungtikan) sarta bias (teu-acak atawa akibat langsung nu disababkeun ku ayana hal nu teu pakait ku variabel mandiri).

Akurasi vs presisi - analogi target

Akurasi nyaéta tingkat kadeukeutan sedengkeun présisi nyaéta tingkat kamampuh dijieun deui. Analogi dipaké di dieu keur nerangkeun béda antara akurasi jeung présisi nyaéta babandingan target. In this analogy, repéated méasurements are compared to arrows that are fired at a target. Accuracy describes the closeness of arrows to the bullseye at the target center. Arrows that strike closer to the bullseye are considered more accurate. The closer a system's méasurements to the accepted value, the more accurate the system is considered to be.

To continue the analogy, if a large number of arrows are fired, precision would be the size of the arrow cluster. (When only one arrow is fired, precision is the size of the cluster one would expect if this were repéated many times under the same conditions.) When all arrows are grouped tightly together, the cluster is considered precise since they all struck close to the same spot, if not necessarily néar the bullseye. The méasurements are precise, though not necessarily accurate. Further example, if a méasuring rod is supposed to be ten yards long but is only 9 yards, 35 inches méasurements can be precise but inaccurate. The méasuring rod will give consistently similar results but the results will be consistently wrong.

However, it is not possible to reliably achieve accuracy in individual méasurements without precision — if the arrows are not grouped close to one another, they cannot all be close to the bullseye. (Their average position might be an accurate estimation of the bullseye, but the individual arrows are inaccurate.) See also Circular error probable for application of precision to the science of ballistics.

Accuracy and precision in logic level modeling and IC simulation
As described in the SIGDA Newsletter [Vol 20. Number 1, June 1990] a common mistake in evaluation of accurate modéls is to compare a logic simulation modél to a transistor circuit simulation modél. This is a comparison of differences in precision, not accuracy. Precision is méasured with respect to detail and accuracy is méasured with respect to réality. Another reference for this topic is "Logic Level Modelling", by John M. Acken, Encyclopedia of Computer Science and Technology, Vol 36, 1997, page 281-306.

Quantifying accuracy and precision
idéally a méasurement device is both accurate and precise, with méasurements all close to and tightly clustered around the known value. The accuracy and precision of a méasurement process is usually established by repéatedly méasuring some traceable reference standard. Such standards are defined in the International System of Units and maintained by national standards organizations such as the National Institute of Standards and Technology.

Precision is usually characterised in terms of the standard deviation of the méasurements, sometimes incorrectly called the méasurement process's standard error. The interval defined by the standard deviation is the 68.3% ("one sigma") confidence interval of the méasurements. If enough méasurements have been made to accurately estimate the standard deviation of the process, and if the méasurement process produces normally distributed errors, then it is likely that 68.3% of the time, the true value of the méasured property will lie within one standard deviation, 95.4% of the time it will lie within two standard deviations, and 99.7% of the time it will lie within three standard deviations of the méasured value.

This also applies when méasurements are repéated and averaged. In that case, the term standard error is properly applied: the precision of the average is equal to the known standard deviation of the process divided by the square root of the number of méasurements averaged. Further, the central limit theorem shows that the probability distribution of the averaged méasurements will be closer to a normal distribution than that of individual méasurements.

With regard to accuracy we can distinguish:
the difference between the mean of the méasurements and the reference value, the bias. Establishing and correcting for bias is necessary for calibration.
the combined effect of that and precision.

A common convention in science and engineering is to express accuracy and/or precision implicitly by méans of significant figures. Here, when not explicitly stated, the margin of error is understood to be one-half the value of the last significant place. For instance, a recording of 843.6 m, or 843.0 m, or 800.0 m would imply a margin of 0.05 m (the last significant place is the tenths place), while a recording of 8436 m would imply a margin of error of 0.5 m (the last significant digits are the units).

A réading of 8000 m, with trailing zeroes and no decimal point, is ambiguous; the trailing zeroes may or may not be intended as significant figures. To avoid this ambiguity, the number could be represented in scientific notation: '8.0 x 10³ m' indicates that the first zero is significant (hence a margin of 50 m) while '8.000 x 10³ m' indicates that all three zeroes are significant, giving a margin of 0.5 m. Similarly, it is possible to use a multiple of the basic méasurement unit: '8.0 km' is equivalent to '8.0 x 10³ m'. In fact, it indicates a margin of 0.05 km (50 m). However, reliance on this convention can léad to false precision errors when accepting data from sources that do not obey it.

Looking at this in another way, a value of 8 would méan that the méasurement has been made with a precision of '1' (the méasuring instrument was able to méasure only up to 1's place) wheréas a value of 8.0 (though mathematically equal to 8) would méan that the value at the first decimal place was méasured and was found to be zero. (The méasuring instrument was able to méasure the first decimal place.) The second value is more precise. Neither of the méasured values may be accurate (the actual value could be 9.5 but méasured inaccurately as 8 in both instances). Thus, accuracy can be said to be the 'correctness' of a méasurement, while precision could be identified as the ability to resolve smaller differences.

Precision is sometimes stratified into:
Repeatability - the variation arising when all efforts are made to keep conditions constant by using the same instrument and operator, and repéating during a short time period; and
Reproducibility - the variation arising using the same méasurement process among different instruments and operators, and over longer time periods.

A common way to statistically méasure precision is a Six Sigma tool called ANOVA Gage R&R. As stated before, you can be both accurate and precise. For instance, if all your arrows hit the bull's eye of the target, they are all both néar the "true value" (accurate) and néar one another (precise).

Something to think about: In the NFL, a place kicker makes 9 of 10 field goals, and another makes 6 of 10. Even if the 6 that the second kicker made were straight down the middle and the first kicker just made his in, he is still less accurate and less precise than the first kicker. This differs from the darts example because either you maké it or you do not; there are not different levels of points that can be scored.

Accuracy in biostatistics
"Accuracy" is also used as a statistical méasure of how well a binary classification test correctly identifies or excludes a condition.

That is, the accuracy is the proportion of true results (both true positives and true negatives) in the population. It is a paraméter of the test.

An accuracy of 100% méans that the test identifies all sick and well péople correctly.

Also see Specificity (tests) and Sensitivity (tests).

Accuracy may be determined from Sensitivity and Specificity, provided Prevalence is known, using the equation:

Accuracy and precision in psychometrics
In psychometrics the terms accuracy and precision are interchangéably used with validity and reliability respectively. Validity of a méasurement instrument or psychological test is established through experiment or correlation with behavior. Reliability is established with a variety of statistical technique (classically Cronbach's alpha).

See also
 Calculation of glass properties - Decréasing accuracy of experimental data in modérn scientific publications for some glass properties

Rujukan
 Accuracy and Precision

Biostatistika
Statistika
Téori statistik
Psikométrika
Évaluasi
Kualitas pipikiran

Akurasi jeung présisi


A youth center or youth centre, often called youth club, is a place where young people can meet and participate in a variety of activities, for example table football, association football (US soccer, UK football), basketball, table tennis, video games, occupational therapy and religious activities.  Youth clubs and centres vary in their activities across the globe, and have diverse histories based on shifting cultural, political and social contexts and relative levels of state funding or voluntary action.

Young social groups
Many youth clubs are set up to provide young people with activities designed to keep them off the streets and out of trouble, and to give them a job and an interest in activity. Some youth clubs can have a particular compelling force, such as music, spiritual/religious guidance and advice or characteristics such as determination.

In the United Kingdom, there are a number of national youth club networks, including:
 UK Youth
 Ambition
 National Association of Boys and Girls Clubs

In the United States, the Boys & Girls Clubs of America is one of the most popular (or well known) youth clubs.

Projects and activities
Many youth clubs and projects are open to all people aged 15–21, although some clubs may still accept young people as old as 25. There are places where young people can meet with friends and practice new activities. Many youth clubs offer various activities, such as table tennis.

Youth clubs are there to help young people understand the world around them. They are there to advise young people with their future, to talk about the past and even help them with the present. Many clubs hold different sessions to educate young people about different topics regarding their health and worries, e.g. contraception. Youth clubs normally have a leader youth worker who normally organizes trips or workshops for the young people to contribute in, e.g. Show Racism the Red Card. They can also hold charity events and even volunteer to do many different things. Youth clubs will sometimes help young people to gain qualifications for their life ahead, e.g. The Duke of Edinburgh's Award.

See also
List of youth organizations
Salford Lads Club
Essex Boys and Girls Clubs
Teen center

References

Youth organizations

Youth center


Epistolae familiares is the title of a collection of letters of Petrarch which he edited during his lifetime.  He originally called the collection Epistolarum mearum ad diversos liber ("a book of my letters to different people") but this was later shortened to the current title.

Petrarch discovered the text of Cicero's letters in 1345, which gave him the idea to collect his own sets of letters. It wasn't until four or five years later however, that he actually got started. He collected his letter correspondence in two different time periods. They are referred to as Epistolae familiares and Seniles.

Epistolae familiares (a.k.a. Familiar Letters) was largely collected during his stay in Provence about 1351 to 1353, however was not ultimately completed until 1359 when he was in Milan. Petrarch had this collection of letters copied onto parchment in 1359 by a certain ingeniosus homo et amicus with another complete copy done in 1364. He added letters in 1366, bringing his first collection of letters to 350. He broke these down and sorted them into 24 volumes. This first collection of letters called Epistolae familiares were actually written between the years 1325 and 1366 (the first translation into English was done by historian James Harvey Robinson in 1898 in his book The First Modern Scholar and Man of Letters).

In January 1350 Petrarch wrote a lengthy letter to his dear friend ("Socrates" as Petrarch liked to call him) dedicating the collection to him. He requests his friend to keep the letters safely out of sight of the censors and critics.  It has since been discovered that Socrates was the Flemish Benedictine monk and music theorist Lodewijk Heyligen whose acquaintance Petrarch had made in the circle of cardinal Giovanni Colonna in Avignon.

Seniles
Petrarch begun a second collection of letters in 1361, also known as Letters of Old Age. It contains 128 letters written between 1361 and 1373. It is also broken down and sorted into volumes (18 books). The final letter, the first and only of the 18th book is his incomplete Letter to Posterity. Some English translations of this collection of letters that are out of copyright are available here A complete English translation is also available in two volumes from Italica Press, translated by Aldo S. Bernardo, formerly Distinguished Professor Emeritus of Italian and Comparative Literature, State University of New York at Binghamton.

Letters of interest
Letter to Posterity
Ascent of Mont Ventoux
Letter VI.2 to Fra Giovanni Colonna

Litterae variae
There are many letters that Petrarch lost or did not keep a copy of. Others he destroyed the originals of for fear they would bring much criticism to his larger collection. There is a collection of 59 of these letters by Giuseppe Fracassetti.

Sine nomine
This special set (Book Without A Name) of letters Petrarch was too fond of to let out of his hands of some nineteen letters was kept out of the main body of Familiar Letters to give respect to the papacy and the controversial lavish lifestyle practiced at Avignon. Liber sine nomine is an epitome of this same work in one volume without a title (which is 19 letters).

References

English translations
 Francesco Petrarch, Letters on Familiar Matters (Rerum familiarium libri), translated by Aldo S. Bernardo  (New York: Italica Press, 2005). Volume 1, Books 1-8; Volume 2, Books 9-16; Volume 3, Books 17-24.
 Francesco Petrarch, Letters of Old Age (Rerum senilium libri), translated by Aldo S. Bernardo, Saul Levin &  Reta A. Bernardo (New York: Italica Press, 2005). Volume 1, Books 1-9; Volume 2, Books 10-18.

External links
Oxford University reference to Prose, ed. G.Martillotti, P.G.Ricci, E.Carrara, E.Bianchi, Milano-Napoli, 1955 The Latin Works of Petrarch.
Examples of Petrarch's letters from Epistolae familiares in Latin only from Italian institution Biblioteca Italiana
Examples of Petrarch's letters from Seniles in Latin only from Italian institution Biblioteca Italiana
Complete list of all the books and the letters within the collection as titled by Aldo S. Bernardo.
Medieval Sourcebook: Francesco Petrarch: Letters, c 1372
Francesco Petrarch - Life Stories, Books, and Links
Familiar Letters with some English translations
University of Chicago: Renaissance Humanism
Petrarch's preface to his Familiar Letters
SophiArte on Petrarch's letters
Seniles: Volumes 9 - 17
The Petrarchan Grotto

Collections of letters
Petrarch
14th-century Latin books

Epistolae familiares