title: Jax (Mortal Kombat)

text: Played by bodybuilder John Parrish, Jax was originally conceived for the game as a kickboxer dressed in shorts and a headband, but this concept was nixed due to potential similarities to "Street Fighter's" boxer character Balrog. Jax was then outfitted in a yellow "gi" with metal forearms that clanged upon impact. Digitized game footage of the character in the costume was shot over two days, during which Parrish accidentally split the pants. The design was aborted thereafter by the developers as they felt the character did not look big enough, so Parrish was called back by Midway several months later for a re-shoot, for which he went shirtless with simple black tights. For "Mortal Kombat 3", he had Jax's bionic implants painted onto his arms, a process that took six hours.


title: Jax (Mortal Kombat)

text: In early development screenshots of "Mortal Kombat 5" (which would become "Deadly Alliance") released to the public in 2001, Jax was seen facing off against Scorpion while wearing his "MK3" costume, but he was given a complete makeover for the finished product with a military-themed outfit consisting of a red beret, sunglasses, and green combat trousers, in addition to a bandolier worn across his chest and a submachine gun that he used in the game as a weapon. Jax wore a green bandana on his head for "MK: Special Forces," while in "MK vs. DC Universe" and the 2011 reboot, he sported a pair of dog tags around his neck. Jax has gone shirtless in all iterations of his main costumes in the "Mortal Kombat" fighting games, with the exception of "MKvsDC," in which he was fully clothed with no skin exposed save for his head and face, and his bionics were adorned with green LED lights.


title: Jax (Mortal Kombat)

text: "Mortal Kombat X" featured DLC costumes centered around the original "Predator" film. Jax in particular received an alternate outfit that made him look like one of the main characters, Al Dillon. If this costume is selected, he is voiced by Dillon's actor, Carl Weathers.


title: Jax (Mortal Kombat)

text: Jax was widely seen as a top-tier character of "Mortal Kombat II". He was considered as such by "GamePro" in their 1993 character rankings, in which they placed him second out of the game's twelve playables behind Mileena: "It’s hard to fight against a good Jax [player] that knows how to control space and use his projectile well." According to "CU Amiga", Jax was "the best all-round character," but "not quite as nimble on his feet as [the] other characters." "Sega Visions" opined that Jax "had the best offense" in the game, while "his slow movement and less-than-powerful uppercut are his weaknesses." According to "Total 64", Jax in "Mortal Kombat Trilogy" is "just the same as he was in "MK3", which isn't a bad thing at all. A top fighter, that is equally good in the air as on the ground."


title: Jax (Mortal Kombat)

text: Prima Games' official guide for "Mortal Kombat: Armageddon" rated Jax overall a 6 out of 10 as "a borderline low-tier character type." According to Alex Vo of GameSpy, he was a "versatile" character but his tonfa weapon style in the game had "no range," while he was best utilized only in distant or up-close combat. In Prima's official guide for the 2011 "Mortal Kombat" reboot, Jax "has generally changed over the years from a defensive machine to an offensive powerhouse," and displays no particular advantage over other characters but is very disadvantaged when playing against Shang Tsung. The publisher additionally considered Jax from "MKII" to be one of the "cheapest" "Mortal Kombat" characters, citing his specials such as his unblockable "Ground Pound" and "Quadruple Slam" while opining that the first game had no such unblockable specials but "that line of sensible thinking was thrown out the window when "Mortal Kombat 2" came around."


title: Jax (Mortal Kombat)

text: While Jax's authority-figure role is unchanged in alternate "Mortal Kombat" media, events leading up to his receiving the bionics have varied. He makes a brief appearance in the 1995 film "Mortal Kombat", accompanying Sonya on a raid on a Hong Kong discothèque in an unsuccessful attempt to capture Kano, and later vainly tries to stop Sonya from pursuing Kano after he baits her into boarding Shang Tsung's ship en route to the tournament. Steve James was originally cast as Jax, but after he died from pancreatic cancer in December 1993, the role went to Gregory McKinney, who had a military background prior to becoming an actor, and his name was misspelled as "Jaxx" in the closing credits.


title: Jax (Mortal Kombat)

text: Jax was a main character in the 1995 theatrical show "", where he was played by Hakim Alston (who had a small role in the first film), Shah Alston, and Tyrone Wiggins (Rain in the second film). He joined Shang Tsung, Ermac, Scorpion, and Raiden in a 2014 "Mortal Kombat" parody animation produced by Comedy Central, in which he was renamed "Leroy Smax" and seen rejecting a request over the phone from "Yao Zhang" (Shang Tsung) to compete in his secret underground tournament, while at home playing a video game dressed only in his underwear and bionic arms.


title: Jax (Mortal Kombat)

text: Jax was a starring character in the 1996 animated series "", where he was portrayed as a cool-minded character who was regularly in an amiable mood, which sometimes clashed with Raiden's dry, sarcastic personality. He was voiced by Dorian Harewood, and his bionics were again removable while functional by way of a set of control chips. In the noncanonical plot of one episode, Jax becomes romantically involved with a female ninja named Ruby, who is secretly working with Shao Kahn in his attempt to trap the Earth defenders in Outworld.


title: Jax (Mortal Kombat)

text: He was among the many main characters recast for the 1997 sequel "", in which he was played by former "American Gladiators" actor Lynn Red Williams that sees him bewildered at occurring supernatural events following Shao Kahn's invasion of Earth. Jax is first seen on an operating table inside a medical facility, with his implants ("cybernetic strength enhancers") already in place without explanation, and the only indication of his military rank is when he introduces himself to Jade as "Major Jackson Briggs." Jax and Sonya fight, and defeat, Cyrax and one of Kahn's extermination squads inside the facility, but they later come into conflict with one another due to Sonya's sustained grief over Johnny Cage's earlier death and her refusal to fill Jax in on the details of the Earthrealmers' mission, and they temporarily split apart as a result. They ultimately reunite with Liu Kang and Kitana and succeed in stopping Kahn from bringing Earth to ruin.


title: Jax (Mortal Kombat)

text: In Kevin Tancharoen's 2010 short film "", and the 2011 "" web series, Michael Jai White played Jax as a police detective in the fictional location of Deacon City. In the first and second episodes, he and Stryker lead a SWAT team in a raid on Kano and the Black Dragon's warehouse to find and rescue Sonya. Jax confronts and fights Kano, during which he punches Kano forcefully enough to detach his right eye, but his arms are then severely damaged after he saves Sonya from an offscreen grenade explosion. White said in a 2011 interview with MTV that he was originally to play Jax in the first "Mortal Kombat" film, but he turned it down in order to star in HBO's 1995 Mike Tyson biopic. He was again cast as Jax in "Annihilation" before ultimately dropping out upon being cast in the title role of "Spawn".


title: Jax (Mortal Kombat)

text: Jax had an expanded role in the novelization of the first film, which included a detailed opening scene of a joint operation of arresting Black Dragon members by the Special Forces and an international task force that goes south after Kano kills the task force's lieutenant. After Sonya's disappearance following her boarding of the ship, Jax works with his unit to find her, including consulting a wizened fighting-tournament expert at Liu Kang's Shaolin temple. When the Earthrealmers return home victorious at the conclusion, Jax reunites with Sonya and they arrest Kano.


title: Jax (Mortal Kombat)

text: He is a featured character in the 1994 Midway-produced "Mortal Kombat II" comic book that was written and illustrated by series co-creator John Tobias and used to set up the events leading to the second tournament. Jax is first seen interrogating Johnny Cage about Sonya's whereabouts in the wake of the violent aftermath of Liu Kang's victory over Shang Tsung in the Shaolin Tournament and disbelieves Cage's revelation that Sonya and Kano had teamed up in fending off Goro, but after Sonya (with Kano) contacts Jax from Outworld, Jax realizes Cage was telling the truth and tracks him down at a movie studio, but Shao Kahn's forces have already invaded Earth and Jax ends up battling Kintaro in an inconclusive fight before Liu Kang and Kung Lao intervene. He was given a Special Forces partner named Beran, created exclusively for the comic and modeled after Midway art director Steve Beran; he is killed near the conclusion by Mileena off-panel. Jax has only a single-panel cameo in the special-edition "Mortal Kombat 4" comic packaged with the 1998 PC release of the game, contacting Sonya by radio as she pursues Jarek.


title: Jax (Mortal Kombat)

text: In Malibu Comics' "Mortal Kombat" comic series, Jax first appears with other "MKII" characters in the September–November 1994 "Goro: Prince of Pain" three-issue miniseries, which tied into the 1994 "Blood & Thunder" six-issue story arc. Like in the game, he is on a mission to find the missing Sonya, starting by confronting Shang Tsung on his island before Tsung transports him to Outworld. Jax eventually reunites with her and they apprehend Kano at the "Tournament Edition" conclusion of both storylines. In the miniseries "U.S. Special Forces," released in two parts in January and February 1995, he and Sonya work to capture an original Black Dragon character named Rojack. Jax then featured in the six-part "Battlewave" miniseries that year, where he is brutally attacked by Goro and left in a coma, but awakens to take out Jade and Smoke when they attempt to assassinate him in the hospital. After Sonya is abducted by Kintaro while returning to Shang Tsung's island to investigate the attack on Jax, Jax himself joins Cage on a plane bound for Outworld, where they again thwart an attack by Jade and Smoke by way of Jax blowing Smoke (transformed into pure smoke) out through a hole in the plane. He and the Earthrealmers then succeed in breaking up a wedding between a brainwashed Sonya and Shao Kahn. In the "Tournament Edition II" wrap-up of the miniseries, Jax's arms are severely damaged by Baraka, setting up the plot for the implants, but this was never explored as the series was canceled in August 1995, shortly after the issue was released.


title: Jax (Mortal Kombat)

text: An action figure of Jax was released by Toy Island in 1996 as part of their "Mortal Kombat Trilogy" line. He and Reptile were featured in an "X-Ray" pack of two six-inch figures with transparent upper bodies that were based on the 2011 reboot and produced by Jazwares. The company also released a four-inch Jax figure in 2012 that was packaged with an Uzi submachine gun (which was not in the game), but the figure was discontinued after only several months in release. Jax was one of twenty series characters featured on 2.5" x 3.5" collectible magnets by Ata-Boy Wholesale in 2011.


title: Jax (Mortal Kombat)

text: The character has received positive reception, though mostly for his design from "Mortal Kombat 3" and onward. Jax placed tenth in UGO's 2012 list of the top fifty "Mortal Kombat" characters. Den of Geek ranked him 27th in their 2015 rating of the series' 64 playable characters for his role as the "cool as hell ... super-strong Army dude," while his ""Mortal Kombat 4" ending is memorable for all the wrong reasons." Anthony Severino of Game Revolution ranked Jax eighth in his 2003 selection of the "Top 10 Old-School Mortal Kombat Characters," Armando Rodriguez of 411mania.com placed Jax seventh in his 2011 selection of the best "Mortal Kombat" characters. However, GameFront called him "a character no one cares about," and while Game Rant ranked him tenth on the list of the "ten most awesome" series characters in 2011, labeling his "Gotcha Grab" and "Air Back Breaker" specials from "Mortal Kombat II" as two of the "most satisfying moves from the original trilogy," they described his design therein as "a third-tier WWE star in tight Lycra pants." Shea Serrano of Grantland rated Jax last (twelfth) in his 20th-anniversary ranking of the "Mortal Kombat II" roster: "What a dud ... He was supposed to be a military bro but did exactly zero cool military-bro shit." Dustin Thomas of Destructoid ranked the "MKII" version of Jax fifth in his 2014 selection of the five worst series characters ("a generic black guy with a mustache and a muscle-gut"), citing his cybernetic arms as his only distinctive feature.


title: Jax (Mortal Kombat)

text: Reaction to Jax's Fatalities has been more mixed. His "Arm Rip" from "Mortal Kombat II" was voted by the readers of "GamePro" as the best "Mortal Kombat" finishing move in 1995. IGN, in 2006, named it as the tenth best gore effect in video game history, and Thomas called it the character's "one redeeming quality" in "MKII". "Complex" ranked his "Head Clap" Fatality from the game as the 14th best finishing move in the series: "Jax did to opponents' heads what Gallagher does to watermelons." His "Giant Stomp" from "Mortal Kombat 3," in which he grows off-screen to a gargantuan height and then crushes his opponent with his foot, was included in IGN's 2010 ranking of their "Unofficial Top 10 List" of the best series finishers, but made GamePro's 2008 list of the 12 "LAMEST" Fatalities: "If you have the ability to grow to 200 feet tall, you should probably unleash it at the beginning of a battle instead of the end." "Game Informer" rated the "Arm Rip" among their picks of the series' best Fatalities, but included the "Giant Stomp" among the "most confusing." CJ Smillie of Game Rant ranked his "Three Points" Fatality from the 2011 "Mortal Kombat" reboot as the ninth best from that game: "It’s simple, it looks devastatingly brutal, and it’s creative to boot." None of his finishers made Prima Games' 2014 listing of the series' top fifty Fatalities. Kevin Wong of WhatCulture named his "T-Wrecks" from "Mortal Kombat X" as the game's top "disgusting" Fatality ("Jax ... lights a cigar, rips open his opponent’s face along the jaw, and stubs out his cigar on the spurting mouth wound. It doesn’t get any more demeaning and objectifying than that").


title: Jax (Mortal Kombat)

text: Jax has received negative attention for his "Mortal Kombat 4" ending. Cracked included it in their 2013 feature "6 Video Game Endings That Are Clearly F#@%ing With Us," saying of Jarek's pleading for his life as Jax dangles him over the cliff precipice, "What follows is one of the stupidest exchanges I can remember in a video game. ... It's hard to put into words just how bad that acting is." In 2010, 4thletter.net listed the "MK4" endings, exemplified with the Nintendo 64 version of Jax's ending, among the "Top Ten Ridiculous Things to Come out of Mortal Kombat," and ranked it 19th in their 2013 countdown of the top fighting game endings. "Jax easily has the best, especially since it’s an extension of Jarek’s ending, which is sort of an extension of Sonya’s ending. ... It's so beautifully shitty." Robert Naytor of Hardcore Gaming 101 remarked, "Not every ending [in the game] is quite to that level of masterful writing." Smosh rated it among their six "Worst Endings in Video Game History."


title: Jax (Mortal Kombat)

text: "Complex" included Jax among the fifty greatest soldiers in video games, placing him at 47th in 2013.


title: Jax (Mortal Kombat)

text: Meagan Marie of "Game Informer" named him among the "biggest beefcakes" in video gaming in 2009, alongside the likes of Duke Nukem and Kratos. In a 2008 feature on the stereotyping of African-American characters in video games, "The Escapist" criticized the "ridiculous" attributes of black characters from "violent" fighting games, citing as examples Jax's "Machine Gun" special move (from "Deadly Alliance" and "MK vs. DC Universe") and T.J. Combo's "Target Practice" finisher from "Killer Instinct 2" in which he pulls out a gun and fatally shoots his opponent.


title: Jax (Mortal Kombat)

text: Ken Begg of Jabootu's Bad Movie Dimension praised Jax's portrayal in the first film in that he "spoke and acted like ... a highly trained and well-educated tactical police officer," but criticized him as "stereotypical street-black" in "Mortal Kombat: Annihilation" while opining that a scene therein of Sonya clashing with Jax about the Earthrealmers' mission "could easily be seen as an exchange between the audience and the screenwriters." Eric Snider of Film.com said of Williams' performance, "Since he’s The Black Guy, the movie makes him say things like 'That’s what I’m talkin’ about!' and 'Let's do this!'" Blair Marnell of CraveOnline praised White's performance in the first episode of "Mortal Kombat: Legacy": "White really carries the piece as Jax ... this is a Jax that I can buy as a main character." IGN described White in the series as "doing what he does best—kicking some serious ass."


title: Oculomotor nerve

text: The oculomotor nerve, also known as the third cranial nerve, cranial nerve III, or simply CN III, is a cranial nerve that enters the orbit through the superior orbital fissure and innervates extraocular muscles that enable most movements of the eye and that raise the eyelid. The nerve also contains fibers that innervate the intrinsic eye muscles that enable pupillary constriction and accommodation (ability to focus on near objects as in reading). The oculomotor nerve is derived from the basal plate of the embryonic midbrain. Cranial nerves IV and VI also participate in control of eye movement.


title: Oculomotor nerve

text: The oculomotor nerve originates from the third nerve nucleus at the level of the superior colliculus in the midbrain. The third nerve nucleus is located ventral to the cerebral aqueduct, on the pre-aqueductal grey matter. The fibers from the two third nerve nuclei located laterally on either side of the cerebral aqueduct then pass through the red nucleus. From the red nucleus fibers then pass via the substantia nigra to emerge from the substance of the brainstem at the oculomotor sulcus (a groove on the lateral wall of the interpeduncular fossa).


title: Oculomotor nerve

text: On emerging from the brainstem, the nerve is invested with a sheath of pia mater, and enclosed in a prolongation from the arachnoid. It passes between the superior cerebellar (below) and posterior cerebral arteries (above), and then pierces the dura mater anterior and lateral to the posterior clinoid process, passing between the free and attached borders of the tentorium cerebelli.


title: Oculomotor nerve

text: It traverses the cavernous sinus, above the other orbital nerves receiving in its course one or two filaments from the cavernous plexus of the sympathetic nervous system, and a communicating branch from the ophthalmic division of the trigeminal nerve. As the oculomotor nerve enters the orbit via the superior orbital fissure it then divides into a superior and an inferior branch.


title: Oculomotor nerve

text: The "superior branch" of the oculomotor nerve or the "superior division", the smaller, passes medially over the optic nerve. It supplies the superior rectus and levator palpebrae superioris.


title: Oculomotor nerve

text: The "inferior branch" of the oculomotor nerve or the "inferior division", the larger, divides into three branches.


title: Oculomotor nerve

text: All these branches enter the muscles on their ocular surfaces, with the exception of the nerve to the inferior oblique, which enters the muscle at its posterior border.


title: Oculomotor nerve

text: The oculomotor nerve (CN III) arises from the anterior aspect of mesencephalon (midbrain). There are two nuclei for the oculomotor nerve:


title: Oculomotor nerve

text: Sympathetic postganglionic fibres also join the nerve from the plexus on the internal carotid artery in the wall of the cavernous sinus and are distributed through the nerve, e.g., to the smooth muscle of superior tarsal (Mueller's) muscle.


title: Oculomotor nerve

text: The oculomotor nerve includes axons of type GSE, general somatic efferent, which innervate skeletal muscle of the levator palpebrae superioris, superior rectus, medial rectus, inferior rectus, and inferior oblique muscles. (Innervates all the extrinsic muscles except superior oblique and lateral rectus.)


title: Oculomotor nerve

text: The nerve also includes axons of type GVE, general visceral efferent, which provide preganglionic parasympathetics to the ciliary ganglion. From the ciliary ganglion postganglionic fibers pass through the short ciliary nerve to the constrictor pupillae of the iris and the ciliary muscles.


title: Oculomotor nerve

text: In people with diabetes and older than 50 years of age, an oculomotor nerve palsy, in the classical sense, occurs with sparing (or preservation) of the pupillary reflex. This is thought to arise due to the anatomical arrangement of the nerve fibers in the oculomotor nerve; fibers controlling the pupillary function are superficial and spared from ischemic injuries typical of diabetes. On the converse, an aneurysm which leads to compression of the oculomotor nerve affects the superficial fibers and manifests as a third nerve palsy with loss of the pupillary reflex (in fact, this third nerve finding is considered to represent an aneurysm—until proven otherwise—and should be investigated).


title: Oculomotor nerve

text: Cranial nerves III, IV, and VI are usually tested together as part of the cranial nerve examination. The examiner typically instructs the patient to hold his head still and follow only with the eyes a finger or penlight that circumscribes a large "H" in front of the patient. By observing the eye movement and eyelids, the examiner is able to obtain more information about the extraocular muscles, the levator palpebrae superioris muscle, and cranial nerves III, IV, and VI. Loss of function of any of the eye muscles results in ophthalmoparesis.


title: Oculomotor nerve

text: Since the oculomotor nerve controls most of the eye muscles, it may be easier to detect damage to it. Damage to this nerve, termed oculomotor nerve palsy, is known by its "down and out" symptoms, because of the position of the affected eye (lateral, downward deviation of gaze).


title: Oculomotor nerve

text: The oculomotor nerve also controls the constriction of the pupils and thickening of the lens of the eye. This can be tested in two main ways. By moving a finger toward a person's face to induce accommodation, their pupils should constrict.


title: Oculomotor nerve

text: Shining a light into one eye should result in equal constriction of the other eye. Fibers from the optic nerves cross over in the optic chiasm with some fibers passing to the contralateral optic nerve tract. This is the basis of the "swinging-flashlight test".


title: Oculomotor nerve

text: Loss of accommodation and continued pupillary dilation can indicate the presence of a lesion on the oculomotor nerve.


title: Secondary source

text: In scholarship, a secondary source is a document or recording that relates or discusses information originally presented elsewhere. A secondary source contrasts with a primary source, which is an original source of the information being discussed; a primary source can be a person with direct knowledge of a situation or a document created by such a person.


title: Secondary source

text: A secondary source is one that gives information about a primary source. In this source, the original information is selected, modified and arranged in a suitable format. Secondary sources involve generalization, analysis, interpretation, or evaluation of the original information.


title: Secondary source

text: The most accurate classification for any given source is not always obvious. "Primary" and "secondary" are relative terms, and some sources may be classified as primary or secondary, depending on how they are used. A third level, the tertiary source, such as an encyclopedia or dictionary, resembles a secondary source in that it contains analysis, but attempts to provide a broad introductory overview of a topic.


title: Secondary source

text: Information can be taken from a wide variety of objects, but this classification system is only useful for a class of sources that are called symbolic sources. Symbolic sources are sources that are intended to communicate information to someone. Common symbolic sources include written documents such as letters and notes, but not, for example, bits of broken pottery and scraps of food excavated from a midden, regardless of how much information can be extracted from an ancient trash heap, or how little can be extracted from a written document.


title: Secondary source

text: Many sources can be considered either primary or secondary, depending on the context in which they are used. Moreover, the distinction between "primary" and "secondary" sources is subjective and contextual, so that precise definitions are difficult to make. For example, if a historical text discusses old documents to derive a new historical conclusion, it is considered to be a primary source for the new conclusion, but a secondary source of information found in the old documents. Other examples in which a source can be both primary and secondary include an obituary or a survey of several volumes of a journal counting the frequency of articles on a certain topic.


title: Secondary source

text: Whether a source is regarded as primary or secondary in a given context may change, depending upon the present state of knowledge within the field. For example, if a document refers to the contents of a previous but undiscovered letter, that document may be considered "primary", since it is the closest known thing to an original source, but if the letter is later found, it may then be considered "secondary".


title: Secondary source

text: Attempts to map or model scientific and scholarly communication need the concepts of primary, secondary and further "levels". One such model is the UNISIST model of information dissemination. Within such a model these concepts are defined in relation to each other, and the acceptance of this way of defining the concepts are connected to the acceptance of the model.


title: Secondary source

text: Some other modern languages use more than one word for the English word "source". German usually uses "Sekundärliteratur" ("secondary literature") for secondary sources for historical facts, leaving "Sekundärquelle" ("secondary source") to historiography. A "Sekundärquelle" is a source which can tell about a lost "Primärquelle" ("primary source"), such as a letter quoting from minutes which are no longer known to exist, and so cannot be consulted by the historian.


title: Secondary source

text: Primary source materials are typically defined as "original research papers written by the scientists who actually conducted the study." An example of primary source material is the Purpose, Methods, Results, Conclusions sections of a research paper (in IMRAD style) in a scientific journal by the authors who conducted the study. In some fields, a secondary source may include a summary of the literature in the introduction of a scientific paper, a description of what is known about a disease or treatment in a chapter in a reference book, or a synthesis written to review available literature. A survey of previous work in the field in a primary peer-reviewed source is secondary source information. This allows secondary sourcing of recent findings in areas where full review articles have not yet been published.


title: Secondary source

text: A book review that contains the judgment of the reviewer about the book is a primary source for the reviewer's opinion, and a secondary source for the contents of the book. A summary of the book within a review is a secondary source.


title: Secondary source

text: In library and information sciences, secondary sources are generally regarded as those sources that summarize or add commentary to primary sources in the context of the particular information or idea under study.


title: Secondary source

text: An important use of secondary sources in the field of mathematics has been to make difficult mathematical ideas and proofs from primary sources more accessible to the public; in other sciences tertiary sources are expected to fulfill the introductory role.


title: Secondary source

text: Secondary sources in history and humanities are usually books or scholarly journals, from the perspective of a later interpreter, especially by a later scholar. In the humanities, a peer reviewed article is always a secondary source.


title: Secondary source

text: The delineation of sources as primary and secondary first arose in the field of historiography, as historians attempted to identify and classify the sources of historical writing. In scholarly writing, an important objective of classifying sources is to determine the independence and reliability of sources. In original scholarly writing, historians rely on primary sources, read in the context of the scholarly interpretations.


title: Secondary source

text: Following the Rankean model established by German scholarship in the 19th century, historians use archives of primary sources. Most undergraduate research projects rely on secondary source material, with perhaps snippets of primary sources.


title: Secondary source

text: In the legal field, source classification is important because the persuasiveness of a source usually depends upon its history. Primary sources may include cases, constitutions, statutes, administrative regulations, and other sources of binding legal authority, while secondary legal sources may include books, the headnotes of case reports, articles, and encyclopedias. Legal writers usually prefer to cite primary sources because only primary sources are authoritative and precedential, while secondary sources are only persuasive at best.


title: Secondary source

text: "A secondary source is a record or statement of an event or circumstance made by a non-eyewitness or by someone not closely connected with the event or circumstances, recorded or stated verbally either at or sometime after the event, or by an eye-witness at a time after the event when the fallibility of memory is an important factor." Consequently, according to this definition, a first-hand account written long after the event "when the fallibility of memory is an important factor" is a secondary source, even though it may be the first published description of that event.


title: Secondary source

text: An autobiography can be a secondary source in history or the humanities when used for information about topics other than its subject. For example, many first-hand accounts of events in World War I written in the post-war years were influenced by the then prevailing perception of the war which was significantly different from contemporary opinion.


title: Greek chorus

text: A Greek chorus, or simply chorus (), in the context of ancient Greek tragedy, comedy, satyr plays, and modern works inspired by them, is a homogeneous, non-individualised group of performers, who comment with a collective voice on the dramatic action. The chorus consisted of between 12 and 50 players, who variously danced, sang or spoke their lines in unison, and sometimes wore masks.


title: Greek chorus

text: Historian H. D. F. Kitto argues that the term "chorus" gives us hints about its function in the plays of ancient Greece: "The Greek verb "choreuo", 'I am a member of the chorus', has the sense 'I am dancing'. The word "ode" means not something recited or declaimed, but 'a song'. The 'orchestra', in which a chorus had its being, is literally a 'dancing floor'." From this, it can be inferred that the chorus danced and sang poetry.


title: Greek chorus

text: Plays of the ancient Greek theatre always included a chorus that offered a variety of background and summary information to help the audience follow the performance. They commented on themes, and, as August Wilhelm Schlegel proposed in the early 19th century to subsequent controversy, demonstrated how the audience might react to the drama. According to Schlegel, the Chorus is "the ideal spectator", and conveys to the actual spectator "a lyrical and musical expression of his own emotions, and elevates him to the region of contemplation". In many of these plays, the chorus expressed to the audience what the main characters could not say, such as their hidden fears or secrets. The chorus often provided other characters with the insight they needed.


title: Greek chorus

text: Some historians argue that the chorus was itself considered to be an actor. Scholars have considered Sophocles to be superior to Euripides in his choral writing. Of the two, Sophocles also won more dramatic contests. His chorus passages were more relevant to the plot and more integrated in tragedies, whereas the Euripidean choruses seemingly had little to do with the plot and were often bystanders. Aristotle stated in his "Poetics":


title: Greek chorus

text: The chorus represents, on stage, the general population of the particular story, in sharp contrast with many of the themes of the ancient Greek plays which tended to be about individual heroes, gods, and goddesses. They were often the same sex as the main character. In Aeschylus' "Agamemnon", the chorus comprises the elderly men of Argos, whereas in Euripides' "The Bacchae", they are a group of eastern bacchantes, and in Sophocles' "Electra", the chorus represents the women of Argos. In Aeschylus' "The Eumenides", however, the chorus takes the part of a host of avenging Furies.


title: Greek chorus

text: The lines of choral odes provide evidence that they were sung. Normal syllabic structure has long sounds that are twice the length of short sounds. However, some lyrics in Greek odes have long syllables that are equal to 3, 4 and 5 shorter syllables. Spoken words cannot do that, suggesting that this was a danced and sung rhythm.


title: Greek chorus

text: The chorus originally consisted of fifty members, but some later playwrights changed the size. Aeschylus likely lowered the number to twelve, and Sophocles raised it again to fifteen. Fifteen members were used by Euripides and Sophocles in tragedies. The chorus stood in the orchestra. There were twenty-four members in comedies.


title: Greek chorus

text: The chorus performed using several techniques, including singing, dancing, narrating, and acting. There is evidence that there were strong rhythmic components to their speaking.


title: Greek chorus

text: They often communicated in song form, but sometimes spoke their lines in unison. The chorus had to work in unison to help explain the play as there were only one to three actors on stage who were already playing several parts each. As the Greek theatres were so large, the chorus' actions had to be exaggerated and their voices clear so that everyone could see and hear them. To do this, they used techniques such as synchronization, echo, ripple, physical theatre and the use of masks to aid them. A Greek chorus was often led by a "coryphaeus". They also served as the ancient equivalent for a curtain, as their "parodos" (entering procession) signified the beginnings of a play and their "exodos" (exit procession) served as the curtains closing.


title: Greek chorus

text: Before the introduction of multiple, interacting actors by Aeschylus, the Greek chorus was the main performer in relation to a solitary actor. The importance of the chorus declined after the 5th century BCE, when the chorus began to be separated from the dramatic action. Later dramatists depended on the chorus less than their predecessors. As dialogue and characterization became more important, the chorus made less of an appearance. However, historian Alan Hughes argues that there was no such thing as decline, but rather the slow dissolution of one form into another:


title: Greek chorus

text: Musical theatre and grand opera sometimes incorporate a singing chorus that serves a similar purpose as the Greek chorus, as noted in "Six Plays by Rodgers and Hammerstein": "The singing chorus is used frequently to interpret the mental and emotional reactions of the principal characters, after the manner of a Greek chorus."


title: Greek chorus

text: During the Italian Renaissance, there was a renewed interest in the theatre of ancient Greece. The Florentine Camerata crafted the first operas out of the intermezzi that acted as comic or musical relief during the dramas of the time. These were based entirely on the Greek chorus, as historian H.C. Montgomery argues.


title: Greek chorus

text: Richard Wagner discussed Greek drama and the Greek chorus extensively in his writings, including "Art and Revolution". His longest work, "Der Ring des Nibelungen", ("The Ring of the Nibelung") is based in the style of "Oresteia" with parallels in rhythm and overall structure (both have three parts, with the exception of "Das Rheingold", the prelude to "The Ring of the Nibelung"). Wagner said of himself, "History gave me a model also for that ideal relation of the theater to the public which I had in mind. I found it in the drama of Ancient Athens". A Greek chorus is also used in the Woody Allen film "Mighty Aphrodite", in which the chorus gives advice to the neurotic main character.


title: Paris La Défense Arena

text: Paris La Défense Arena (originally known as the U Arena) is a multi-use domed stadium in Nanterre, a western suburb of Paris. Opened in October 2017, it was developed by the rugby union club Racing 92, and replaced Stade Olympique Yves-du-Manoir as their home field. It is one of the two multi-use domed stadiums to be built in Europe, along with Telenor Arena and is Europe’s largest indoor arena. Its naming rights are held by Paris La Défense, the management company of the nearby La Défense business district.


title: Paris La Défense Arena

text: The venue offers three separate configurations. In its rugby configuration, it has a nominal seating capacity of 30,681. For concerts, it is able to seat 40,000. Finally, a movable stand allows it to also be used for a variety of indoor sports, at various capacities, with a capacity of as low as 5,000 being possible. The venue also includes of office space, 300 student rooms, shops, including a club shop, a brewery and a gourmet restaurant.


title: Paris La Défense Arena

text: It is scheduled to host swimming at the 2024 Summer Olympics. Due to IOC sponsorship regulations, the venue will be referred to as Arena 92.


title: Paris La Défense Arena

text: The stadium was originally planned to open in 2014, but that date was delayed, due to local protests.


title: Paris La Défense Arena

text: It eventually opened in October 2017, although Racing 92 did not play their first home game in the new stadium until they hosted Toulouse on 22 December 2017. The stadium's working name was changed from "Arena92" to "U Arena"; referencing the configuration of the main stands, and the structure's shape, when viewed from the air, in November 2016. The name was changed a second time to the current Paris La Défense Arena on 12 June 2018. This followed a 10-year naming rights agreement with Paris La Défense, the company that manages the nearby La Défense business district.


title: Paris La Défense Arena

text: The venue was originally planned to have a retractable roof, but it was ultimately built with a fixed roof instead.


title: Paris La Défense Arena

text: The Rolling Stones were the first band to ever perform a concert in the stadium, closing their Europe-only No Filter Tour, with three shows, on 19, 22, and 25 October 2017. The arena's first rugby union match, took place on 25 November 2017 between France and Japan. On 11 March 2018, the French professional basketball clubs Nanterre 92 and ASVEL Basket, played each other in a LNB Pro A 2017–18 season game. The game had an attendance of 15,220, which was the highest attendance of any game in the league's history. Since 2017 it has hosted the Paris Motocross.


title: Jet injector

text: A jet injector is a type of medical injecting syringe device used for a method of drug delivery known as jet injection, in which a narrow, high-pressure stream of liquid penetrates the outermost layer of the skin (stratum corneum) to deliver medication to targeted underlying tissues of the epidermis or dermis ("cutaneous" injection, also known as classical "intradermal" injection), fat ("subcutaneous" injection), or muscle ("intramuscular" injection).


title: Jet injector

text: The jet stream is usually generated by the pressure of a piston in an enclosed liquid-filled chamber. The piston is usually pushed by the release of a compressed metal spring, although investigational devices may use piezoelectric effects and other novel technologies to pressurize the liquid in the chamber. The springs of currently-marketed and historical devices may be compressed by operator muscle power, hydraulic fluid, built-in battery-operated motors, compressed air or gas, and other means. Gas-powered and hydraulically powered devices may involve hoses that carry compressed gas or hydraulic fluid from separate cylinders of gas, electric air pumps, foot-pedal pumps, or other components to reduce the size and weight of the hand-held part of the system and to allow faster and less-tiring methods to perform consecutive vaccinations.


title: Jet injector

text: Jet injectors were used for mass vaccination, and as an alternative to needle syringes for diabetics to inject insulin. However, the World Health Organization no longer recommends jet injectors for vaccination due to risks of disease transmission. Similar devices are used in other industries to inject grease or other fluid.


title: Jet injector

text: The term "hypospray", although better known within science fiction, originates from an actual jet injector known as the Hypospray and has been cited within several scientific articles.


title: Jet injector

text: A jet injector, also known as a jet gun injector, air gun, or pneumatic injector, is a medical instrument that uses a high-pressure jet of liquid medication to penetrate the skin and deliver medication under the skin without a needle. Jet injectors can be single-dose or multi-dose jet injectors.


title: Jet injector

text: Throughout the years jet injectors have been redesigned to overcome the risk of carrying contamination to subsequent subjects. To try to stop the risk, researchers placed a single-use protective cap over the reusable nozzle. The protective cap was intended to act as a shield between the reusable nozzle and the patient's skin. After each injection the cap would be discarded and replaced with a sterile one. These devices were known as protector cap needle-free injectors or PCNFI. A safety test by Kelly and colleagues (2008) found a PCNFI device failed to prevent contamination. After administering injections to hepatitis B patients, researchers found hepatitis B had penetrated the protective cap and contaminated the internal components of the jet injector, showing that the internal fluid pathway and patient contacting parts cannot safely be reused.


title: Jet injector

text: Researchers developed a new jet injection design by combining the drug reservoir, plunger and nozzle into a single-use disposable cartridge. The cartridge is placed onto the tip of the jet injector and when activated a rod pushes the plunger forward. This device is known as a disposable-cartridge jet injectors (DCJI).


title: Jet injector

text: The International Standards Organization recommended abandoning the use of the name "jet injector", which is associated with a risk of cross-contamination and rather refer to newer devices as "needle-free injectors".


title: Jet injector

text: Diabetics have been using jet injectors in the United States for at least 20 years. These devices have all been spring-loaded. At their peak, jet injectors accounted for only 7% of the injector market. Currently, the only model available in the United States is the Injex 23. In the United Kingdom, the Insujet has recently entered the market. As of June 2015, the Insujet is available in the UK and a few select countries.


title: Jet injector

text: Researchers from the University of Twente in the Netherlands patented a Jet Injection System, comprising a microfluidic device for jet ejection and a laser-based heating system. A continuous laser beam – also called a continuous-wave laser – heats the liquid to be administered, which is then launched in a droplet form across the epidermis and then slows down into the tissue below.


title: Jet injector

text: Since the jet injector breaks the barrier of the skin, there is a risk of blood and biological material being transferred from one user to the next. Research on the risks of cross-contamination arose immediately after the invention of jet injection technology.


title: Jet injector

text: Splash-back refers to the jet stream penetrating the outer skin at a high velocity causing the jet stream to ricochet backwards and contaminate the nozzle.


title: Jet injector

text: Instances of splash-back have been published by several researchers. Samir Mitragrotri visually captured splash-back after discharging a multi-use nozzle jet injector using high-speed microcinematography. Hoffman and colleagues (2001) also observed the nozzle and internal fluid pathway of the jet injector becoming contaminated.


title: Jet injector

text: Fluid suck-back occurs when blood left on the nozzle of the jet injector is sucked back into the injector orifice, contaminating the next dose to be fired.


title: Jet injector

text: The CDC has acknowledged that the most widely used jet injector in the world, the Ped-O-Jet, sucked fluid back into the gun. "After injections, they [CDC] observed fluid remaining on the Ped-O-Jet nozzle being sucked back into the device upon its cocking and refilling for the next injection (beyond the reach of alcohol swabbing or acetone swabbing)," stated Dr. Bruce Weniger.


title: Jet injector

text: Retrograde flow happens after the jet stream penetrates the skin and creates a hole, if the pressure of the jet stream causes the spray, after mixing with tissue fluids and blood, to rebound back out of the hole, against the incoming jet stream and back into the nozzle orifice.


title: Jet injector

text: Hepatitis B can be transmitted by less than one nanolitre so makers of injectors must ensure there is no cross-contamination between applications. The World Health Organization no longer recommends jet injectors for vaccination due to risks of disease transmission.


title: Jet injector

text: Numerous studies have found cross-infection of diseases from jet injections. An experiment using mice, published in 1985, showed that jet injectors would frequently transmit the viral infection lactate dehydrogenase elevating virus (LDV) from one mouse to another. Another study used the device on a calf, then tested the fluid remaining in the injector for blood. Every injector they tested had detectable blood in a quantity sufficient to pass on a virus such as hepatitis B.


title: Jet injector

text: From 1984 to 1985, a weight-loss clinic in Los Angeles administered human chorionic gonadotropin (hCG) with a Med-E-Jet injector. A CDC investigation found 57 out of 239 people who had received the jet injection tested positive for hepatitis B.


title: Jet injector

text: Jet injectors have also been found to inoculate bacteria from the environment into users. In 1988 a podiatry clinic used a jet injector to deliver local anaesthetic into patients' toes. Eight of these patients developed infections caused by "Mycobacterium chelonae". The injector was stored in a container of water and disinfectant between use, but the organism grew in the container. This species of bacteria is sometimes found in tap water, and had been previously associated with infections from jet injectors.


title: Riemannian geometry

text: <section begin="Lede" />Riemannian geometry is the branch of differential geometry that studies Riemannian manifolds, smooth manifolds with a "Riemannian metric", i.e. with an inner product on the tangent space at each point that varies smoothly from point to point. This gives, in particular, local notions of angle, length of curves, surface area and volume. From those, some other global quantities can be derived by integrating local contributions.


title: Riemannian geometry

text: Riemannian geometry originated with the vision of Bernhard Riemann expressed in his inaugural lecture ""Ueber die Hypothesen, welche der Geometrie zu Grunde liegen"" ("On the Hypotheses on which Geometry is Based.") It is a very broad and abstract generalization of the differential geometry of surfaces in R. Development of Riemannian geometry resulted in synthesis of diverse results concerning the geometry of surfaces and the behavior of geodesics on them, with techniques that can be applied to the study of differentiable manifolds of higher dimensions. It enabled the formulation of Einstein's general theory of relativity, made profound impact on group theory and representation theory, as well as analysis, and spurred the development of algebraic and differential topology.<section end="Lede" />


title: Riemannian geometry

text: Riemannian geometry was first put forward in generality by Bernhard Riemann in the 19th century. It deals with a broad range of geometries whose metric properties vary from point to point, including the standard types of non-Euclidean geometry.


title: Riemannian geometry

text: Every smooth manifold admits a Riemannian metric, which often helps to solve problems of differential topology. It also serves as an entry level for the more complicated structure of pseudo-Riemannian manifolds, which (in four dimensions) are the main objects of the theory of general relativity. Other generalizations of Riemannian geometry include Finsler geometry.


title: Riemannian geometry

text: There exists a close analogy of differential geometry with the mathematical structure of defects in regular crystals. Dislocations and disclinations produce torsions and curvature.


title: Riemannian geometry

text: What follows is an incomplete list of the most classical theorems in Riemannian geometry. The choice is made depending on its importance and elegance of formulation. Most of the results can be found in the classic monograph by Jeff Cheeger and D. Ebin (see below).


title: Riemannian geometry

text: The formulations given are far from being very exact or the most general. This list is oriented to those who already know the basic definitions and want to know what these definitions are about.


title: Riemannian geometry

text: In all of the following theorems we assume some local behavior of the space (usually formulated using curvature assumption) to derive some information about the global structure of the space, including either some information on the topological type of the manifold or on the behavior of points at "sufficiently large" distances.


title: Sergey Prokudin-Gorsky

text: Sergey Mikhaylovich Prokudin-Gorsky (;  – September 27, 1944) was a Russian chemist and photographer. He is best known for his pioneering work in color photography and his effort to document early 20th-century Russia.


title: Sergey Prokudin-Gorsky

text: Using a railroad-car darkroom provided by Tsar Nicholas II, Prokudin-Gorsky traveled the Russian Empire from around 1909 to 1915 using his three-image colour photography to record its many aspects. While some of his negatives were lost, the majority ended up in the US Library of Congress after his death. Starting in 2000, the negatives were digitised and the colour triples for each subject digitally combined to produce hundreds of high-quality colour images of Russia and its neighbors from over a century ago.


title: Sergey Prokudin-Gorsky

text: Prokudin-Gorsky was born in Murom in the ancestral estate of Funikova Gora, in what is now Kirzhachsky District, Vladimir Oblast. His parents were of the Russian nobility, and the family had a long military history. They moved to Saint Petersburg, where Prokudin-Gorsky enrolled in Saint Petersburg State Institute of Technology to study chemistry under Dmitri Mendeleev. He also studied music and painting at the Imperial Academy of Arts.


title: Sergey Prokudin-Gorsky

text: In 1890, Prokudin-Gorsky married Anna Aleksandrovna Lavrova, and later the couple had two sons, Mikhail and Dmitri, and a daughter, Ekaterina. Anna was the daughter of the Russian industrialist Aleksandr Stepanovich Lavrov, an active member in the Imperial Russian Technical Society (IRTS). Prokudin-Gorsky subsequently became the director of the executive board of Lavrov's metal works near Saint Petersburg and remained so until the October Revolution. He also joined Russia's oldest photographic society, the photography section of the IRTS, presenting papers and lecturing on the science of photography.


title: Sergey Prokudin-Gorsky

text: In 1901, Prokudin-Gorsky established a photographic studio and laboratory in Saint Petersburg. The following year, he travelled to Berlin and spent 6 weeks studying colour sensitization and three-colour photography with photochemistry professor Adolf Miethe, the most advanced practitioner in Germany at that time. Throughout the years, Prokudin-Gorsky's photographic work, publications and slide shows to other scientists and photographers in Russia, Germany and France earned him praise, and in 1906 he was elected the president of the IRTS photography section and editor of Russia's main photography journal, the "Fotograf-Liubitel". Gorsky was a member of the Royal Photographic Society between 1920 and 1932.


title: Sergey Prokudin-Gorsky

text: Perhaps Prokudin-Gorsky's best-known work during his lifetime was his color portrait of Leo Tolstoy, which was reproduced in various publications, on postcards, and as larger prints for framing. The fame from this photo and his earlier photos of Russia's nature and monuments earned him invitations to show his work to the Russian Grand Duke Michael Alexandrovich and Dowager Empress Maria Feodorovna in 1908, and to Tsar Nicholas II and his family in 1909. The Tsar enjoyed the demonstration, and, with his blessing, Prokudin-Gorsky got the permission and funding to document Russia in color. In the course of ten years, he was to make a collection of 10,000 photos. Prokudin-Gorsky considered the project his life's work and continued his photographic journeys through Russia until after the October Revolution. Under the new regime he was forced to accept a professorship and in August 1918 was ordered by the Education Ministry to procure projection equipment in Norway. He still pursued scientific work in color photography, published papers in English photography journals and, together with his colleague S. O. Maksimovich, obtained patents in Germany, England, France and Italy.


title: Sergey Prokudin-Gorsky

text: In 1920, Prokudin-Gorsky remarried and had a daughter with his assistant Maria Fedorovna née Schedrina. The family finally settled in Paris in 1922, reuniting with his first wife and children. Prokudin-Gorsky set up a photo studio there together with his three adult children, naming it after his fourth child, Elka. In the 1930s, the elderly Prokudin-Gorsky continued with lectures showing his photographs of Russia to young Russians in France, but stopped commercial work and left the studio to his children, who named it Gorsky Frères. He died in Paris on September 27, 1944, a month after the Liberation of Paris. He is buried in the Sainte-Geneviève-des-Bois Russian Cemetery.


title: Sergey Prokudin-Gorsky

text: The method of color photography used by Prokudin-Gorsky was first suggested by James Clerk Maxwell in 1855 and demonstrated in 1861, but good results were not possible with the photographic materials available at that time. In imitation of the way a normal human eye senses color, the visible spectrum of colors was divided into three channels of information by capturing it in the form of three black-and-white photographs, one taken through a red filter, one through a green filter, and one through a blue filter. The resulting three photographs could be projected through filters of the same colors and exactly superimposed on a screen, synthesizing the original range of color additively; or viewed as an additive color image by one person at a time through an optical device known generically as a chromoscope or photochromoscope, which contained colored filters and transparent reflectors that visually combined the three into one full-color image; or used to make photographic or mechanical prints in the complementary colors cyan, magenta and yellow, which, when superimposed, reconstituted the color subtractively.


title: Sergey Prokudin-Gorsky

text: The first person to widely demonstrate good results by this method was Frederic E. Ives, whose "Kromskop" system of viewers, projectors and camera equipment was commercially available from 1897 until about 1907. Only the viewers and ready-made triple photographs for use in them sold in any significant quantity. Still life arrangements, unpopulated landscapes and oil paintings were the typical subject matter, but a few examples of color portraiture from life were also offered.


title: Sergey Prokudin-Gorsky

text: Another very notable practitioner was Adolf Miethe, with whom Prokudin-Gorsky studied in Germany in 1902. Miethe was a photochemist who greatly improved the panchromatic characteristics of the black-and-white photographic materials suitable for use with this method of color photography. He presented projected color photographs to the German Imperial Family in 1902 and was exhibiting them to the general public in 1903, when they also began to appear in periodicals and books. Miethe took the first known aerial color photographs, from a hot air balloon, in 1906.


title: Sergey Prokudin-Gorsky

text: In England in 1899 Ives's former assistant, Edward Sanger-Shepherd, commercialized the application of the three-colour process in the "Sanger Shepherd process of natural colour photography". With his process in 1903 and 1904 Sarah Angelina Acland produced the first substantial body of work in colour photography by an amateur photographer. By 1905 seventeen different photographers had shown three-colour slides by the Sanger-Shepherd process at exhibitions of the Royal Photographic Society in England.


title: Sergey Prokudin-Gorsky

text: Photographic plates, which had the light-sensitive emulsion coated on a thin sheet of glass, were normally used instead of flexible film, both because a general transition from glass plates to plastic film was still in progress and because glass provided the best dimensional stability for three images intended to match up perfectly when they were later combined.


title: Sergey Prokudin-Gorsky

text: An ordinary camera could be used to take the three pictures, by reloading it and changing filters between exposures, but pioneering color photographers usually built or bought special cameras that made the procedure less awkward and time-consuming. One of the two main types used beam splitters to produce three separate images in the camera, making all three exposures at the same time and from the same viewpoint. Although a camera of this type was ideal in theory, such cameras were optically complicated and delicate, and liable to get out of adjustment. Some designs were also subject to optical phenomena that could cause noticeably uneven color or other defects in the results. The other, more robust type was an essentially ordinary camera with a special sliding holder for the plates and filters that allowed each in turn to be efficiently shifted into position for exposure—an operation sometimes partly or even entirely automated with a pneumatic mechanism or spring-powered motor.


title: Sergey Prokudin-Gorsky

text: When the three color-filtered photographs were not taken at the same time, anything in the scene that did not hold steady during the entire operation would exhibit colored "fringes" around its edges in the resulting color image. If it moved continuously across the scene, three separate strongly-colored "ghost" images could result. Such color artifacts are plainly visible in ordinary color composites of many of Prokudin-Gorsky's photographs, but special digital image processing software was used to artificially remove them, whenever possible, from the composites of all 1,902 of the images commissioned by the Library of Congress in 2004. The altered versions have proliferated online and older or third-party versions showing these tell-tale peculiarities are increasingly scarce.


title: Sergey Prokudin-Gorsky

text: Adolf Miethe designed a high-quality, sequential-exposure color camera, which was manufactured by Bermpohl and became available commercially in 1903. Prokudin-Gorsky published an illustration of it in "Fotograf-Liubitel" in 1906. The most common model used a single oblong plate 9 cm wide by 24 cm high, the same format as Prokudin-Gorsky's surviving negatives, and it photographed the images in unconventional blue-green-red sequence, which is also a characteristic of Prokudin-Gorsky's negatives if the usual upside-down image in a camera and gravity-compliant downward shiftings of his plates are assumed. An inventor as well as a photographer, Prokudin-Gorsky patented an optical system for cameras of the simultaneous-exposure type, and it is often claimed or implied that he invented, or at least built, the camera used for his Russian Empire project. No definite written or photographic documentation of his field equipment is known to exist, only the evidence inherent in the photographs themselves, and no rationale has been suggested for going to the trouble and expense of building a functionally identical copy of a Miethe-Bermpohl camera instead of simply buying one.


title: Sergey Prokudin-Gorsky

text: Miethe and Bermpohl also produced a matching three-color projector and a chromoscope. The Goerz optical company made a differently configured and more powerful three-color projector for Miethe. It, too, was commercially available.


title: Sergey Prokudin-Gorsky

text: The required exposure time depended on the lighting conditions, the sensitivity of the photographic plate, and the camera lens aperture used. In a letter to Leo Tolstoy requesting a portrait sitting, Prokudin-Gorsky described the exposure as taking one to three seconds, but later, when recollecting his time with Tolstoy, he described a six-second exposure on a sunny day. Blaise Agüera y Arcas studied one landscape view, photographed in broad daylight but showing a clear, well-defined moon, and used the moon's movement to estimate that the whole procedure of three filtered exposures and two repositionings of the camera's plate holder had taken over a minute. The lens aperture Prokudin-Gorsky chose to use greatly affected the exposure time required. A small aperture is often used for landscape photography because it allows objects at various distances to all be sharply imaged at the same time, while the use of a large aperture is common for portraiture and plainly evident in the Tolstoy portrait. All other factors being equal, if for example a 16-second exposure was required when using a -inch-diameter aperture, an exposure of only 1 second would suffice with a 1-inch aperture.


title: Sergey Prokudin-Gorsky

text: Prokudin-Gorsky was also acquainted with the use of Autochrome color plates, which did not require a special camera or projector. He was one of the favored few the Lumière Brothers introduced to their new product in 1906, the year before it went into commercial production. Autochrome plates were expensive and not sensitive enough for casual "snapshots" with a hand-held camera, but their use was simple and in expert hands they were capable of producing excellent results. They made color photography truly practical for advanced amateurs and led some pioneering users of color separation cameras to abandon their methods as outmoded, but Prokudin-Gorsky was not won over. No Autochromes by Prokudin-Gorsky are known to survive.


title: Sergey Prokudin-Gorsky

text: Although photographic color prints of the images were difficult to make at the time and slide show lectures consumed much of the time Prokudin-Gorsky used to demonstrate his work, photomechanical color prints of some were published in journals and books, and his studio issued some, most notably the Tolstoy portrait, as postcards and large photogravures. Many of the original prints published by his studio still survive.


title: Sergey Prokudin-Gorsky

text: Prokudin-Gorsky's own inventions, some of them collaborative, led to the granting of numerous patents, most issued during the years of his voluntary exile and not directly related to the body of work on which his fame now rests. Some concern processes for making subtractive color transparencies, which do not require any special projection or viewing equipment. Examples of these were preserved by Prokudin-Gorsky's family and have recently appeared online. Most of his patents relate to the production of natural-color motion pictures, a potentially lucrative application that attracted the attention of many inventors in the field of color photography during the 1910s and 1920s.


title: Sergey Prokudin-Gorsky

text: Around 1905, Prokudin-Gorsky envisioned and formulated a plan to use the emerging technological advances that had been made in color photography to document the Russian Empire systematically. Through such an ambitious project, his ultimate goal was to educate the schoolchildren of Russia with his "optical color projections" of the vast and diverse history, culture, and modernization of the empire.


title: Sergey Prokudin-Gorsky

text: Outfitted with a specially equipped railroad-car darkroom provided by Tsar Nicholas II and in possession of two permits that granted him access to restricted areas and cooperation from the empire's bureaucracy, Prokudin-Gorsky documented the Russian Empire between around 1909 and 1915. He conducted many illustrated lectures of his work. His photographs offer a vivid portrait of a lost world—the Russian Empire on the eve of World War I and the coming Russian civil war. His subjects ranged from the medieval churches and monasteries of old Russia, to the railroads and factories of an emerging industrial power, to the daily life and work of Russia's diverse population.


title: Sergey Prokudin-Gorsky

text: It has been estimated from Prokudin-Gorsky's personal inventory that before leaving Russia, he had about 3,500 negatives. Upon leaving the country and exporting all his photographic material, about half of the photos were confiscated by Russian authorities for containing material they deemed strategically sensitive for war-time Russia. According to Prokudin-Gorsky's notes, the photos left behind were not of interest to the general public. Some of Prokudin-Gorsky's negatives were given away, and some he hid on his departure. Outside the Library of Congress collection, none has yet been found.


title: Sergey Prokudin-Gorsky

text: By the time of Prokudin-Gorsky's death, the Tsar and his family had long since been executed during the Russian civil war, and most of the former empire was now the Soviet Union. The surviving boxes of photo albums and fragile glass plates the negatives were recorded on were finally stored in the basement of a Parisian apartment building, and the family was worried about them getting damaged. The United States Library of Congress purchased the material from Prokudin-Gorsky's heirs in 1948 for $3,500–$5,000 on the initiative of a researcher inquiring into their whereabouts. The library counted 1,902 negatives and 710 album prints without corresponding negatives in the collection.


title: Sergey Prokudin-Gorsky

text: Due to the very specialized and labor-intensive processes required to make photographic color prints from the negatives, only about a hundred of the images were used in exhibits, books and scholarly articles during the half-century after the Library of Congress acquired them. Their widest exposure was in the 1980 coffee table book "Photographs for the Tsar: The Pioneering Color Photography of Sergei Mikhailovich Prokudin-Gorskii Commissioned by Tsar Nicholas II", in which the color images are combined yellow, magenta and cyan ink-on-paper halftones mass-produced with a multicolor printing press in the usual way.


title: Sergey Prokudin-Gorsky

text: It was only with the advent of digital image processing that multiple images could be quickly and easily combined into one. The Library of Congress undertook a project in 2000 to make digital scans of all the photographic material received from Prokudin-Gorsky's heirs and contracted with the photographer Walter Frankhauser to combine the monochrome negatives into color images. He created 122 color renderings using a method he called digichromatography and commented that each image took him around six to seven hours to align, clean and color-correct. In 2001, the Library of Congress produced an exhibition from these, "The Empire That Was Russia: The Prokudin-Gorskii Photographic Record Recreated". The photographs have since been the subject of many other exhibitions in the area where Prokudin-Gorsky took his photos.


title: Sergey Prokudin-Gorsky

text: In 2004, the Library of Congress contracted with computer scientist Blaise Agüera y Arcas to produce an automated color composite of each of the 1,902 negatives from the high-resolution digital images of the glass-plate negatives. He applied algorithms to compensate for the differences between the exposures and prepared color composites of all the negatives in the collection. As the library offers the high-resolution images of the negatives freely on the Internet, many others have since created their own color representations of the photos, and they have become a favorite testbed for computer scientists.


title: Sergey Prokudin-Gorsky

text: Some of Sergey Prokudin-Gorsky's photographs, digitally processed, made available by the Library of Congress:


title: Minecon

text: Minecon (alternatively capitalised as MineCon or MINECON) is an annual interactive livestream and fan convention about the video game "Minecraft", hosted by Mojang. The first gathering in 2010 was known as "MinecraftCon". The event then went by the Minecon name from 2011 to 2019. The Minecon 2011 convention was held in Las Vegas and celebrated the launch of the game with "Minecraft"-related discussion panels and gaming areas. The most recent in-person convention, Minecon 2016, held in Anaheim, had 12,000 attendees. Since 2017, Minecon has taken the form of an interactive livestream and, as such, Minecon 2016 was the last in-person convention to bear the Minecon name. The livestream was called "Minecon Earth" in 2017 and 2018, and was later renamed to "Minecon Live" in 2019 and "Minecraft Live" starting in 2020. The in-person conventions, now to be known as "Minecraft Festival", are planned to return in the future.


title: Minecon

text: MinecraftCon 2010 was a gathering of more than 30 people at Bellevue, Washington, on 31 August. Markus Persson made an appearance at the meet-up when several requests were made for a community meet-up, so he called on the community to pick no specific venue.


title: Minecon

text: 5,000 people attended the first official MineCon convention held in Las Vegas on 18 November 2011. The convention focused on celebrating the game's release and hosted "Minecraft"-related discussion panels, and invited people to play the game with others while at the convention. There were keynote speeches from members of the community, building contests, costume contests and exhibits. One of the many events at MINECON was the "Nether Party", an event for those aged 21 and over, featuring Canadian DJ deadmau5. This event also marked the release of Minecraft 1.0 to the public, officially taking the game out of beta. It was also the first time that Minecraft on the Xbox 360 console was first shown and played outside of the development.


title: Minecon

text: On 2 August 2012, Mojang announced that the 2012 MineCon convention would take place in the Paris Disneyland Park on 24 and 25 November. The announcement was made over the social networking platform Twitter when the game's creator, Markus Persson, posted a short trailer revealing the new convention location. The video shows Mojang team members wearing Disney paraphernalia, and Persson comments to lead developer Jens Bergensten, "I think they are trying to tell us something". Joystiq's JC Fletcher said that the site was a "step up" from the first MINECON's location in Las Vegas. The second annual convention was the first held outside of the United States, making it available to European fans who might not have been able to attend the first. It was held in the wake of "Minecraft"'s growing popularity as the Xbox 360 version of the game sold 3 million copies. 2012 was also the start of several in-game unofficial MINECONs, notably a Virtual MINECON, which although an unofficial event, was attended by a member of the Mojang Team. Many in-game MINECONs have announced an intent to return with the start of the next MINECON.


title: Minecon

text: The convention in 2012 was attended by 4,500 fans. Mojang made several announcements at the 2012 convention. Details about the 1.5 "Redstone" update were revealed as well as information on the game's modding API.


title: Minecon

text: In April 2013, Lydia Winters revealed that MINECON 2013 would be held in the United States. Jens Bergensten later said that it would be on the east coast. On 27 June, it was announced on Mojang's YouTube Channel that MINECON 2013 will be held in Orlando, Florida. The website for the Orange County Convention Center had listed MineCon as an upcoming event in November, with an attendance of 7,500, but then removed the event from the web page. Tickets went on sale in three batches each of 2,500 tickets on 31 July, 2 August, and 3 August. The first batch of 2,500 tickets was sold out in three seconds, according to Mojang COO Vu Bui. The event took place on 2 and 3 November.


title: Minecon

text: On 30 March 2014, Lydia Winters revealed in a tweet that MINECON 2014 would be held in Europe. However, on 21 August 2014, Vu Bui created a blog post, stating that there would be no MineCon 2014, but instead the next MineCon would be in Spring 2015 in London. This was later used on the Bedrock edition's tips as "Nobody remembers where Minecon 2014 was held."


title: Minecon

text: On 2 February 2015, Vu Bui announced MINECON 2015 would be held in London, at the ExCeL London Exhibition and Conference Centre on 4 and 5 July 2015. Ticket prices were announced on 18 March 2015 and were set at £129. During the opening ceremony on 4 July 2015, animated by Element Animation Studios, it was announced by Guinness World Records that MineCon had won the world record for the most attendance for a convention that is solely for one game, selling 10,000 tickets.


title: Minecon

text: On 7 March 2016, Mojang announced in a blog post that MINECON 2016 would be held in Anaheim, California, at the Anaheim Convention Center on 24 and 25 September 2016. They announced new features during that time, such as the Minecraft novel, "Minecraft: The Island", and an update coming to the console versions of the game. promoted in the opening and closing ceremonies a two-part short film from Element Aniamtion, entitled "A Minecraft Adventure".


title: Minecon

text: On 8 August 2017, Mojang announced that MINECON would be taking the form of an interactive livestream on 18 November 2017, dubbed "MINECON Earth". The host of MINECON Earth is Will Arnett, a Canadian actor. After this announcement came the introduction of 'Official Community Events', which allow events such as Minefaire, Minevention and Multiplay's BlockFest to be considered 'Official Minecraft Conventions'.


title: Minecon

text: During MINECON Earth, developers announced the next major update, the "Update Aquatic"; this update was released in July 2018. Vu Bui, COO of Mojang Studios, also announced the winning mob based on a community vote: "The Monster of The Night Skies", later named the "phantom".


title: Minecon

text: On 10 April 2018, Mojang announced that MINECON Earth would be taking place on 29 September 2018 for 90 minutes on stream. During the event, Mojang announced "Minecraft Dungeons", a dungeon-crawler spin-off of "Minecraft", and features of the upcoming "Village & Pillage" update, which was released in April 2019. Viewers voted for one of three in-game biomes to be updated in the next update; the Taiga biome won the vote.


title: Minecon

text: On 17 May 2019, MINECON Live 2019 was announced to be held on 28 September of that year, changing the name of the event from "MINECON Earth" to "MINECON Live" to avoid confusion with their new game "Minecraft Earth". Like the previous year, viewers were able to vote for new features to be added to one of three in-game biomes in a following update; the Mountains biome won the vote. During the livestream, developers of the game announced the "Nether Update", and "Village & Pillage" update, the latter promoted via a Mojang and Element Animation Studios collaboratory episode of "Villager News" starring Dan Lloyd. An early access release date of "Minecraft Earth" was also announced to be for October 2019.


title: Minecon

text: On 28 September 2019, Mojang announced Minecraft Festival, an in-person event that was to be held in Orlando, Florida, on 25–27 September 2020. Due to the fears surrounding the COVID-19 pandemic the main event was postponed to be online while Minecraft Live, the livestream portion of the event, still happened. The livestream aired on 3 October 2020.


title: Minecon

text: The livestream included a mob vote, where users could vote about which "Minecraft" creature should be added into the next update. The three options were Iceologer (featured in "Minecraft Dungeons"), Moobloom (featured in the game "Minecraft Earth") and Glow Squid, with the Glow Squid winning. The livestream also provided details on Minecraft's next big update, "Caves & Cliffs", and a musical "Nether Update Encore" from Element Animation Studios promoting the present version of the game.


title: Minecon

text: Minecraft Live was announced to be held on 16 October 2021. It featured a live mob vote, like previous years, with the options consisting of the Copper Golem, the Glare, and the Allay, the last of which won the vote, as well as another Element Animation Studios musical short film opening the event, describing the features of the previous "The Caves & Cliffs Update Part 1" in song form. The show also announced the theme of the next major update, called "The Wild Update", which overhauled the swamp biome and added an underground biome called the Deep Dark, which was originally planned for "The Caves & Cliffs Update Part 2.


title: Minecon

text: On 28 September 2019, it was announced that there will be a Minecraft Festival, an in-person celebration of "Minecraft", in Orlando, Florida, 25 September 2020. Minecraft Festival was postponed from 25 September 2020, to the same date in 2021, then to sometime in 2022 due to the COVID-19 pandemic. However, on 3 January 2022, it was announced that Minecraft Festival would not happen in 2022.


title: Minecon

text: Minecraft Live 2022 was held on 15 October 2022. It featured an in-game mob vote, unlike previous years, with the options consisting of the Sniffer, the Rascal, and the Tuff Golem, the first of which won the vote. It also announced some basic features for the next update, 1.20, including camels, bamboo wood, and hanging signs. It also announced the basic gameplay for the upcoming game "Minecraft Legends" and the Season 3 update for "Minecraft Dungeons".


title: Twyla Tharp

text: Twyla Tharp (; born July 1, 1941) is an American dancer, choreographer, and author who lives and works in New York City. In 1966 she formed the company Twyla Tharp Dance. Her work often uses classical music, jazz, and contemporary pop music.


title: Twyla Tharp

text: From 1971 to 1988, Twyla Tharp Dance toured extensively around the world, performing original works. In 1973 Tharp choreographed "Deuce Coupe" to the music of The Beach Boys for the Joffrey Ballet. "Deuce Coupe" is considered the first "crossover ballet", a mix of ballet and modern dance. Later she choreographed "Push Comes to Shove" (1976), which featured Mikhail Baryshnikov and is now thought to be the best example of crossover ballet.


title: Twyla Tharp

text: In 1988, Twyla Tharp Dance merged with American Ballet Theatre, since which time ABT has premiered 16 of Tharp's works.


title: Twyla Tharp

text: Tharp was born in 1941 on a farm in Portland, Indiana, the daughter of Lecile Tharp, née Confer, and William Tharp. She was named for Twila Thornburg, the "Pig Princess" of the 89th Annual Muncie Fair.


title: Twyla Tharp

text: As a child, Tharp spent a few months each year living with her Quaker grandparents on their farm in Indiana. Her mother insisted she take lessons in dance, various musical instruments, shorthand, German and French. In 1950, Tharp's family—younger sister Twanette, twin brothers Stanley and Stanford, and her parents—moved to Rialto, California. William and Lecile operated Tharp Motors and Tharp Autos in Rialto. They opened a drive-in movie theater, where Tharp worked. The drive-in was on the corner of Acacia and Foothill, Rialto's major east–west artery and the path of Route 66. She attended Pacific High School in San Bernardino, studied at the Vera Lynn School of Dance, and studied ballet with Beatrice Collenette. A "devoted bookworm", Tharp says her schedule left little time for a social life. She attended Pomona College but transferred to Barnard College, where she graduated with a degree in art history in 1963. In New York City, she studied with Richard Thomas, Martha Graham and Merce Cunningham. In 1963, Tharp joined the Paul Taylor Dance Company.


title: Twyla Tharp

text: In 1965, Tharp choreographed her first dance, "Tank Dive", and formed her own company, Twyla Tharp Dance. Her work often utilizes classical music, jazz, and contemporary pop music. From 1971 to 1988, Twyla Tharp Dance toured extensively around the world, performing original works.


title: Twyla Tharp

text: In 1973, Tharp choreographed "Deuce Coupe" to the music of The Beach Boys for the Joffrey Ballet. "Deuce Coupe" is considered the first crossover ballet. Later she choreographed "Push Comes to Shove" (1976), which featured Mikhail Baryshnikov and is now thought to be the best example of crossover ballet.


title: Twyla Tharp

text: In 1988, Twyla Tharp Dance merged with American Ballet Theatre, since which time ABT has premiered 16 of Tharp's works. In 2010 it had 20 of her works in its repertory. Tharp has since choreographed dances for Paris Opera Ballet, The Royal Ballet, New York City Ballet, Boston Ballet, Joffrey Ballet, Pacific Northwest Ballet, Miami City Ballet, American Ballet Theatre, Hubbard Street Dance and Martha Graham Dance Company. She also created the dance roadshow "Cutting Up" (1992) with Baryshnikov, which went on to tour and appeared in 28 cities over two months.


title: Twyla Tharp

text: In 2000, Twyla Tharp Dance regrouped with entirely new dancers. This company also performed around the world, and with it Tharp developed the material that became "Movin' Out," an award-winning Broadway musical featuring the songs of Billy Joel and starring many of the dancers in the company.


title: Twyla Tharp

text: In 2012, Tharp created the full-length ballet "The Princess and the Goblin", based on George MacDonald's story "The Princess and the Goblin". It is her first ballet to include children, and was co-commissioned by Atlanta Ballet and Royal Winnipeg Ballet and performed by both companies.


title: Twyla Tharp

text: Tharp was the first Artist in Residency (A.I.R.) at Pacific Northwest Ballet in Seattle. During this time she created and premiered "Waiting At The Station", a work with music by R&B artist Allen Toussaint and sets and costumes by longtime collaborator Santo Loquasto.


title: Twyla Tharp

text: In 1980, Tharp's work first appeared on Broadway with Twyla Tharp Dance performing "When We Were Very Young", followed in 1981 by "The Catherine Wheel", her collaboration with David Byrne at the Winter Garden. "Wheel" was broadcast on PBS and its soundtrack released on LP. Her dance piece "Fait Accompli" to music by David Van Tieghem was released on the These Things Happen LP (1984).


title: Twyla Tharp

text: Tharp premiered her dance musical "Movin' Out", set to the music and lyrics of Billy Joel, in Chicago in 2001. The show opened on Broadway in 2002. "Movin' Out" ran for 1,331 performances on Broadway. A national tour opened in January 2004. It received 10 Tony nominations and Tharp won Best Choreographer.


title: Twyla Tharp

text: Tharp opened a new show, "The Times They Are a-Changin'", to the music of Bob Dylan in 2005 at The Old Globe Theatre in San Diego. "The Times They are A-Changin"' set the records for the highest-grossing show and highest ticket sales as of the date of closing (March 2006). It was also the first show to receive a second extension before the first preview. After its run in California, the New York show ran for 35 previews and 28 performances.


title: Twyla Tharp

text: In 2009, Tharp worked with the songs of Frank Sinatra to mount "Come Fly with Me", which ran at the Alliance Theater in Atlanta and was the best-selling four-week run as of the date of closing in 2009. Renamed "Come Fly Away", the show opened on Broadway in 2010 at the Marquis Theatre and ran for 26 previews and 188 performances. "Come Fly Away," was retooled and opened under the title "Sinatra: Dance with Me" at The Wynn Las Vegas in 2011. "Come Fly Away" National Tour opened in Atlanta in August 2011.


title: Twyla Tharp

text: Tharp collaborated with film directors Miloš Forman on "Hair" (1978), "Ragtime" (1980) and "Amadeus" (1983); Taylor Hackford on "White Nights" (1985); and James Brooks on "I'll Do Anything" (1994).


title: Twyla Tharp

text: Television credits include choreographing "Sue's Leg" (1976) for the inaugural episode of the PBS program "Dance in America"; co-producing and directing "Making Television Dance" (1977), which won the Chicago International Film Festival Award; and directing "The Catherine Wheel" (1983) for BBC Television. Tharp co-directed the award-winning television special "Baryshnikov by Tharp" in 1984.


title: Twyla Tharp

text: Tharp has written three books: an early autobiography, "Push Comes to Shove" (1992; Bantam Books); "The Creative Habit: Learn It and Use It for Life" (2003, Simon & Schuster), translated into Spanish, Chinese, Russian, Korean, Thai and Japanese; and "The Collaborative Habit" (2009, Simon & Schuster), also translated into Thai, Chinese and Korean. Tharp indicated that "The Creative Habit" is about cybernetics, especially in the several Greek-themed creative exercises, such as the Coin Drop; the Coin Drop, as an exercise in extracting ordered meaning from chaos, is derived from the astrological muse Urania, in that random coins falling onto a flat surface can be used to develop pattern analysis skills. The astrological theme is an etymological underpinning of cybernetics' tradition of "guiding a boat" by sighting stellar references according to ancient Greek navigation.


title: Twyla Tharp

text: Tharp has received two Emmy Awards, 19 honorary doctorates, the Vietnam Veterans of America President's Award, the 2004 National Medal of the Arts, and numerous grants, including a MacArthur Fellowship. She is a member of the American Academy of Arts and Sciences, the American Philosophical Society, and an Honorary Member of the American Academy of Arts and Letters.


title: Twyla Tharp

text: At the 1982 Barnard College commencement ceremonies, Tharp's alma mater awarded her its highest honor, the Barnard Medal of Distinction.


title: Twyla Tharp

text: She received the Tony Award for Best Choreography and the Drama Desk Award for Outstanding Choreography for "Movin' Out". She received a Drama Desk nomination for Outstanding Choreography for "Singin' in the Rain".


title: Twyla Tharp

text: Tharp was named a Kennedy Center Honoree for 2008. She was inducted into the Academy of Achievement in 1993.


title: Twyla Tharp

text: From 2013 to 2014, the Smithsonian National Portrait Gallery featured Tharp in the critically acclaimed "Dancing the Dream" exhibition as a pioneer of American modern dance.


title: Twyla Tharp

text: Until 1972 Tharp was married to painter Robert Huot, by whom she has a son, Jesse Huot, who acts as her business manager. She also has a grandson.


title: Signalling theory

text: Within evolutionary biology, signalling theory is a body of theoretical work examining communication between individuals, both within species and across species. The central question is when organisms with conflicting interests, such as in sexual selection, should be expected to provide honest signals (no presumption being made of conscious intention) rather than cheating. Mathematical models describe how signalling can contribute to an evolutionarily stable strategy.


title: Signalling theory

text: Signals are given in contexts such as mate selection by females, which subjects the advertising males' signals to selective pressure. Signals thus evolve because they modify the behaviour of the receiver to benefit the signaller. Signals may be honest, conveying information which usefully increases the fitness of the receiver, or dishonest. An individual can cheat by giving a dishonest signal, which might briefly benefit that signaller, at the risk of undermining the signalling system for the whole population.


title: Signalling theory

text: The question of whether selection of signals works at the level of the individual organism or gene, or at the level of the group, has been debated by biologists such as Richard Dawkins, arguing that individuals evolve to signal and to receive signals better, including resisting manipulation. Amotz Zahavi suggested that cheating could be controlled by the handicap principle, where the best horse in a handicap race is the one carrying the largest handicap weight. According to Zahavi's theory, signallers such as male peacocks have 'tails' that are genuinely handicaps, being costly to produce. The system is evolutionarily stable as the large showy tails are honest signals. Biologists have attempted to verify the handicap principle, but with inconsistent results. The mathematical biologist Ronald Fisher analysed the contribution that having two copies of each gene (diploidy) would make to honest signalling, demonstrating that a runaway effect could occur in sexual selection. The evolutionary equilibrium depends sensitively on the balance of costs and benefits.


title: Signalling theory

text: The same mechanisms can be expected in humans, where researchers have studied behaviours including risk-taking by young men, hunting of large game animals, and costly religious rituals, finding that these appear to qualify as costly honest signals.


title: Signalling theory

text: When animals choose mating partners, traits such as signalling are subject to evolutionary pressure. For example, the male gray tree frog, "Hyla versicolor", produces a call to attract females. Once a female chooses a mate, this selects for a specific style of male calling, thus propagating a specific signalling ability. The signal can be the call itself, the intensity of a call, its variation style, its repetition rate, and so on. Various hypotheses seek to explain why females would select for one call over the other. The sensory exploitation hypothesis proposes that pre-existing preferences in female receivers can drive the evolution of signal innovation in male senders, in a similar way to the hidden preference hypothesis which proposes that successful calls are better able to match some 'hidden preference' in the female. Signallers have sometimes evolved multiple sexual ornaments, and receivers have sometimes evolved multiple trait preferences.


title: Signalling theory

text: In biology, signals are traits, including structures and behaviours, that have evolved specifically because they change the behaviour of receivers in ways that benefit the signaller. Traits or actions that benefit the receiver exclusively are called "cues". For example, when an alert bird deliberately gives a warning call to a stalking predator and the predator gives up the hunt, the sound is a "signal". But when a foraging bird inadvertently makes a rustling sound in the leaves that attracts predators and increases the risk of predation, the sound is not a signal, but a cue.


title: Signalling theory

text: Signalling systems are shaped by mutual interests between signallers and receivers. An alert bird such as a Eurasian jay warning off a stalking predator is communicating something useful to the predator: that it has been detected by the prey; it might as well quit wasting its time stalking this alerted prey, which it is unlikely to catch. When the predator gives up, the signaller can get back to other tasks such as feeding. Once the stalking predator is detected, the signalling prey and receiving predator thus have a mutual interest in terminating the hunt.


title: Signalling theory

text: Within species, mutual interests increase with kinship. Kinship is central to models of signalling between relatives, for instance when broods of nestling birds beg and compete for food from their parents.


title: Signalling theory

text: The term honesty in animal communication is controversial because in non-technical usage it implies intent, to discriminate deception from honesty in human interactions. However, biologists use the phrase "honest signals" in a direct, statistical sense. Biological signals, like warning calls or resplendent tail feathers, are honest if they "reliably" convey useful information to the receiver. That is, the signal trait tells the receiver about an otherwise unobservable factor. Honest biological signals do not need to be perfectly informative, reducing uncertainty to zero; all they need to be useful is to be correct "on average", so that some behavioural response to the signal is advantageous, statistically, compared to the behaviour that would occur in absence of the signal. Ultimately the value of the signalled information depends on the extent to which it allows the receiver to increase its fitness.


title: Signalling theory

text: One class of honest signal is the aposematic warning signal, generally visual, given by poisonous or dangerous animals such as wasps, poison dart frogs, and pufferfish. Warning signals are honest indications of noxious prey, because conspicuousness evolves in tandem with noxiousness (a conspicuous, non-noxious organism gets eaten). Thus, the brighter and more conspicuous the organism, the more toxic it usually is. The most common and effective colours are red, yellow, black and white.


title: Signalling theory

text: There is an obvious evolutionary advantage to faking a signal like "Don't eat me, I'm poisonous"; the sender scares off predators without the metabolic cost of actually being toxic. Such fake I'm-harmful signals are called Batesian mimicry. There is also an obvious evolutionary advantage to the predator learning to distinguish the real from the fake signal; this sets off an evolutionary arms race, making such fake signals evolutionarily unstable. An "honest signal", on the other hand, cannot be faked by the sender (the feathers can't look resplendent unless the bird is healthy) or can't be faked without a cost that exceeds the benefit (like incessantly giving warning calls). This unfakability is what makes the signal reliable (and thus "honest"). Hence, "honest" signals are evolutionarily stable.


title: Signalling theory

text: The mathematical biologist John Maynard Smith discusses whether honest signalling must always be costly. He notes that it had been shown that "in some circumstances" a signal is reliable only if it is costly. He states that it had been assumed that parameters such as pay-offs and signalling costs were constant, but that this might be unrealistic. He states that with some restrictions, signals can be cost-free, reliable, and evolutionarily stable. However, if costs and benefits "vary uniformly over the whole range" then indeed honest signals have to be costly.


title: Signalling theory

text: Because there are both mutual and conflicting interests in most animal signalling systems, a central problem in signalling theory is dishonesty or cheating. For example, if foraging birds are safer when they give a warning call, cheats could give false alarms at random, just in case a predator is nearby. But too much cheating could cause the signalling system to collapse. Every dishonest signal weakens the integrity of the signalling system, and so reduces the fitness of the group. An example of dishonest signalling comes from Fiddler crabs such as "Uca lactea mjoebergi", which have been shown to bluff (no conscious intention being implied) about their fighting ability. When a claw is lost, a crab occasionally regrows a weaker claw that nevertheless intimidates crabs with smaller but stronger claws. The proportion of dishonest signals is low enough for it not to be worthwhile for crabs to test the honesty of every signal through combat.


title: Signalling theory

text: Richard Dawkins and John Krebs in 1978 considered whether individuals of the same species would act as if attempting to deceive each other. They applied a "selfish gene" view of evolution to animals' threat displays to see if it would be in their genes' interests to give dishonest signals. They criticised previous ethologists, such as Nikolaas Tinbergen and Desmond Morris, for suggesting that such displays were "for the good of the species". They argued that such communication ought to be viewed as an evolutionary arms race in which signallers evolve to become better at manipulating receivers, while receivers evolve to become more resistant to manipulation. The game theoretical model of the war of attrition similarly suggests that threat displays ought not to convey any reliable information about intentions.