title: Bayonetta 2

text: "Bayonetta 2" adds a new gameplay element called Umbran Climax which can be activated when the player has a full magic gauge. Similar to the state of boss fights in the first game, this technique strengthens Bayonetta's attacks and combos with extra Wicked Weaves and Infernal Demon summons for a short period of time. This increases their overall range and damage and replenishes Bayonetta's health when in use.


title: Bayonetta 2

text: Most of "Bayonetta 2" takes place on the fictional sacred mountain of Fimbulventr and the nearby town of Noatun, both located in the Middle East. The main character Bayonetta (Hellena Taylor / Atsuko Tanaka) travels to the mountain to find the Gates of Hell to save her friend Jeanne (Grey DeLisle-Griffin / Mie Sonozaki).


title: Bayonetta 2

text: Returning characters include Rodin (Dave Fennoy / Tesshō Genda), the bartender of Gates of Hell who supplies Bayonetta with powerful weapons; Luka (Yuri Lowenthal / Daisuke Namikawa), a journalist who provides Bayonetta with valuable information; and Enzo (John Kassir / Wataru Takagi), an informant who provides comic relief. New characters include Loki (Mark Daugherty / Junko Minagawa), an amnesiac boy who guides Bayonetta to the mountain; the Masked Lumen (Crispin Freeman / Takehito Koyasu), a powerful Sage and Bayonetta's new rival; and Loptr (TJ Ramini / Takumi Yamazaki), a mysterious Prophet apparently allied with the Masked Lumen.


title: Bayonetta 2

text: A few months after the first "Bayonetta", Bayonetta is shopping with Enzo when angels attack the city. Teaming up with fellow witch and friend Jeanne, she is on the verge of winning until a demon summoning goes wrong. Jeanne saves Bayonetta from the summon's attack, but the attack causes Inferno to claim her soul. Bayonetta destroys the summon and resolves to save Jeanne. At the same time, a masked Lumen Sage is brought to the present by a mysterious figure, known as the Prophet, who promises him the chance for revenge.


title: Bayonetta 2

text: Upon a tip from her informant Luka, Bayonetta heads to the mountain of Fimbulventr, in the city of Noatun, which houses an entrance to Inferno. In Noatun, she meets a boy called Loki, who is trying to reach Fimbulventr for reasons he cannot remember. The two strike a deal to travel together as Loki claims his powers will be needed in order to reach Inferno. On the way, they learn about some of Loki's lost memories, but are constantly attacked by angels and demons. Loki is hunted by the Lumen Sage and the Prophet, who knows Loki. The Prophet shows Bayonetta a vision that implies the Witch Hunts 500 years ago were not caused by Balder.


title: Bayonetta 2

text: Bayonetta reaches Inferno and travels into its depths to save Jeanne. With the help of Rodin, Bayonetta is able to save Jeanne's soul and revive her. However, the Sage attacks Loki again and reveals himself to be a young Balder. Bayonetta saves Loki from him, but Loki loses control of his powers and sends Bayonetta and Balder 500 years into the past. Now in Vigrid during the Witch Hunts, Bayonetta meets her mother Rosa, and the two work together to fight back against the angels. When they become separated, Bayonetta encounters Loptr, a doppelgänger of Loki who is the Prophet in the present. Loptr claims that the Eyes of the World, one of which Bayonetta possesses, belong to him. Later meeting with the young Balder, Bayonetta arrives too late to stop Loptr from murdering Rosa. Bayonetta realizes that Loptr has tricked Balder into seeking revenge on Loki in the present. The two of them decide to work together and return to the present to stop Loptr. Meanwhile, in the present, Luka encounters Loki, who claims to remember everything, and asks Luka to take him to Fimbulventr.


title: Bayonetta 2

text: With Jeanne's help, Bayonetta and Balder reach the top of Fimbulventr and find Loptr having already captured Loki. Loptr explains that he and Loki were once the God of Chaos, Aesir, the creator of the Eyes of the World. Aesir had split his power amongst humanity to create the Eyes but had also split his soul into two halves of good and evil in the process. Loki, the good half, was given the power to control the Eyes directly, which Loptr steals. Despite their efforts, Loptr takes both of the Eyes from Balder and Bayonetta and transforms into Aesir with the intent to rule humanity. Loki claims that Aesir's power can erase anything from existence, and uses that power to destroy the Eyes, weakening Loptr and allowing Bayonetta and Balder to destroy his body with Jeanne's help. Loptr's soul attempts to escape to a time where the Eyes still exist to try his plan again. Balder stops him and absorbs his soul, despite Loki warning him that doing so will corrupt him. Balder reveals he knows that Bayonetta is his daughter and asks her to stop him should he be corrupted, and is returned to his time. With Loptr and the Eyes gone, Loki says he plans to take a break from the world's affairs, but that he may meet Bayonetta again, and fades away.


title: Bayonetta 2

text: Some days after, Bayonetta and Jeanne are shopping again. Suddenly, another attack begins, and Bayonetta teams up with Jeanne to battle them again.


title: Bayonetta 2

text: In a post-credits scene, Balder is shown returning to his time period, now corrupted, setting up the events of the first "Bayonetta".


title: Bayonetta 2

text: Shortly after the release of "Bayonetta", Hideki Kamiya discussed with Yusuke Hashimoto ideas for sequels and spin-off games from the title. Despite these discussions, Kamiya believed they would never release a sequel. However, Kamiya's Twitter account later stated that he might release the sequel if "Bayonetta" sold well. "Bayonetta 2" was revealed during a Nintendo Direct on September 13, 2012. The reason for the game's Wii U exclusivity was because Nintendo stepped in with additional funding after it was shelved by Sega. PlatinumGames producer Atsushi Inaba, responding to complaints by fans of the original game, stated that "Bayonetta 2" would not exist if Nintendo had not partnered with the developer to make the game. Sega remained as the game's consultant. Work on "Bayonetta 2" was based on feedback the staff received from the original "Bayonetta" to bring various improvements. Nintendo was not involved in the making of the game other than as an "observer" and the staff were pleased with their experience. One of the improvements made by staff was to the movements of enemies: in the first game, there was a single enemy movement when Bayonetta struck them, while in "Bayonetta 2", they have differing animations depending on the direction of Bayonetta's attack. The architecture for the main city environment, Noatun, was based on cities in Belgium and Italy, such as Bruges (church interiors), Brussels (the grand buildings), Florence (city streets and houses) and Venice (the canal network).


title: Bayonetta 2

text: In a Nintendo Direct from January 2013, PlatinumGames showed a development trailer for the game. They confirmed game development was going smoothly, but did not go into many gameplay details. A playable demo of the game was featured at Nintendo's booth during E3 2013, following the reveal of the game's first gameplay trailer. A multiplayer mode was also announced, along with the option of a touch-based control scheme and the confirmation that the game will support Off-TV Play. In the Nintendo Direct from February 2014, another trailer for the game was released, showing off the new environments players can expect as well as some of the basic story elements of the game. Further gameplay was also released, revealing the use of Japanese voice actors for the Japanese release, new weapons for Bayonetta to use as well as the use of the new youth character as being playable. As of the "Bayonetta 2 Direct", the game was released on September 20, 2014 in Japan and in October 2014 for the rest of the world. At E3 2014, it was announced the game would include a port of the original "Bayonetta", which would include exclusive Nintendo costumes, dual audio voice tracks, and touch controls. The original game would be a digital download via the Nintendo eShop and on a separate disc for retailers. To market the release, Nintendo partnered with Playboy to set a photo shoot with Playmate Pamela Horton cosplaying Bayonetta.


title: Bayonetta 2

text: The music of "Bayonetta 2" was composed by a group of members led by Masami Ueda, many of whom returned after being featured on the soundtrack for the first game. Ueda states that he finds the score for "Bayonetta 2" much livelier than the one for "Bayonetta" and explains they attempted to create new elements in the music by switching out certain instruments for others.


title: Bayonetta 2

text: A key difference in the soundtrack between the games is the inclusion of dynamic music for boss fights based on the progression in "Bayonetta 2". Ueda states that the music is broken up into phases and are set off by triggers based on animations and other cues in the scene which allow for swells in the music to match up the action onscreen. A similar approach was done for the stage tracks as well, with as many as 10 shorter loops mixed together that transition based on the player's progress through the stage. Compared to the original "Bayonetta's" 150 tracks, "Bayonetta 2" has 183 tracks with higher audio quality.


title: Bayonetta 2

text: Like the original game, "Bayonetta 2" features a cover of an old song but remixed into the signature style of the games, "Moon River" by Andy Williams. Both the remixed version and the original are included in the game, much like how "Fly Me To The Moon" was used as the main theme song for "Bayonetta". The game's battle theme, "Tomorrow is Mine", was one of the first pieces of music revealed in its entirety during promotion of the game. Both of these songs were performed by Keeley Bumford. Also like the original game, "Bayonetta 2" received a five-disc original soundtrack, which was released in Japan on October 29, 2014.


title: Bayonetta 2

text: "Bayonetta 2" received critical acclaim. It received an aggregated score of 91/100 on Metacritic based on 80 reviews. The Japanese magazine "Famitsu"s four reviewers collectively awarded the game a score of 38 out of 40. "Edge" awarded "Bayonetta 2" a score of 10 out of 10. The magazine's reviewer described it as "a riotous, spectacular work of the highest order of camp" and praised the game for the extent of its customisability and for refining problematic elements from the first "Bayonetta", with tighter pacing and the removal of "sudden, mid-cinematic, instafail QTEs". The reviewer concluded, "This is a game that you can complete in ten hours, but play and replay forever. … It is a masterclass in combat design, in videogame variety, in the balance between accessibility and depth." GameSpot reviewer Mark Walton said the game "will be remembered as an absolute classic" and awarded it a perfect 10/10, the seventh game in the site's history to receive that score. Chris Carter from Destructoid also rated it a 10/10, where he declared it as "one of the finest action games of all time", alongside "Devil May Cry 3".


title: Bayonetta 2

text: Several reviews agreed that the game was an improvement on its predecessor, despite acknowledgement that its combat mechanics were largely unchanged: Eurogamers Martin Robinson concluded, ""Bayonetta 2"s biggest disappointment may be that it's an iterative sequel, but it's not such a problem when it's iterating on genius." IGNs Jose Otero commented that its art direction and pacing "make "Bayonetta 1" look poor by comparison," while GameTrailers called it "sharpened to a nearly flawless degree" compared to its predecessor, praising the variety in addition to the style mixed with the gameplay, where the game "thrives on throwing players into complete madness and letting them conquer it." Chris Carter at Destructoid stated "Four years later and Platinum hasn't lost its edge with "Bayonetta 2". It's just as stylish and as fun as ever"


title: Bayonetta 2

text: Of the game's new features, the co-operative online Tag Climax mode was welcomed by GameSpot's Mark Walton and by Eurogamer's Martin Robinson, who praised it for requiring the player to gain a deep understanding of the combo scoring system; however, IGN's Otero commented that the fun it provides was restricted to short bursts, and Polygon's Arthur Gies found the mode's co-operative mechanics at odds with its competitive focus on scoring. Otero and Robinson both criticized the game's optional touchscreen-based control system, intended to improve accessibility for new players, as very limited in comparison to the game's main control scheme.


title: Bayonetta 2

text: In Japan, "Bayonetta 2" sold approximately 39,000 units in its first week of release, much fewer than were sold of the original "Bayonetta" in its debut week. After its third week of release, "Bayonetta 2" had sold approximately 50,000 units in Japan. The title was the seventh best-selling game in the UK in its first week of release, but was absent from the Top 40 best-seller list in its second week.


title: Bayonetta 2

text: The Nintendo Switch version of "Bayonetta 2" sold 9,532 copies within its first week on sale in Japan, which placed it at number 14 on the all format sales chart. By March 2018, Nintendo confirmed the Switch version had sold 400,000 copies during its first nine weeks, compared to the 300,000 copies the Wii U version sold during the same period. As of December 31, 2021 the Switch version of the game have sold 1.04 million copies worldwide.


title: Bayonetta 2

text: Bayonetta appears as a playable fighter via downloadable content in the 2014 crossover fighting games "Super Smash Bros. for Nintendo 3DS and Wii U", after being one of the most requested characters to be in the game in an official ballot. She fights using various methods including combos, Witch Time, and Bullet Arts abilities from her first two games, and has alternate costumes based on her designs in both "Bayonetta" and "Bayonetta 2". She was revealed on December 15, 2015 during the Super Smash Bros. Final Video Presentation as the winner of the ballot, being claimed to be the number one most requested character worldwide. She was made available alongside a stage based on the Umbra Clock Tower from the original "Bayonetta" on February 3, 2016. All of the aforementioned "Bayonetta" franchise content returned in the Nintendo Switch sequel "Super Smash Bros. Ultimate" in 2018.


title: Ron McGovney

text: Ronald J. McGovney (born November 2, 1963) is an American semi-retired musician, best known as the original bass guitarist in the heavy metal band Metallica from October 1981 to December 1982.


title: Ron McGovney

text: Having previously played with guitarist James Hetfield in the garage band Leather Charm, McGovney was a member of Metallica during its first year of gigging and appeared on their early demos before departing late in 1982. After a period of inactivity, he played in the thrash metal band Phantasm. He later played with Metallica on their 30th anniversary show.


title: Ron McGovney

text: In June 1981, McGovney formed his first band, Leather Charm, with his childhood friend Hetfield and guitarist Hugh Tanner of Hetfield's previous band, Phantom Lord. Tanner soon left Leather Charm to pursue a career in music management; the subsequent lineup featured guitarist Troy James and drummer Jim Mulligan. The group rehearsed a set of new wave of British heavy metal covers and original material for a period of months, but Mulligan's departure later that year led to the band's demise.


title: Ron McGovney

text: Hetfield and drummer Lars Ulrich established their new project, Metallica, in October 1981. With the addition of McGovney and guitarist Dave Mustaine early the next year, the first gigging lineup of the band was completed. After their debut performance on March 14, the band spent 1982 rehearsing in McGovney's parents' long-since-demolished rental property near the 605 freeway and building a local following in the Los Angeles and Orange County heavy metal scenes. They recorded several demos during this time, including one recorded in McGovney's garage, the "Power Metal" demo, and the live "No Life 'Til Leather". A recording of the song "Hit the Lights" with McGovney playing bass was featured on a repressing of the "Metal Massacre Vol. 1" album.


title: Ron McGovney

text: McGovney's time in Metallica was reportedly tumultuous, as he often clashed with Ulrich and Mustaine. He felt that, aside from using his connections made as an amateur photographer, his role was that of monetary and transportation provider, rather than a respected member of the band. He ultimately quit on December 10, 1982, due to growing tensions, and was replaced by Cliff Burton. After leaving Metallica, McGovney became uninterested in playing music and sold most of his equipment.


title: Ron McGovney

text: In 1986, Hirax vocalist Katon W. De Pena persuaded McGovney to return to music. The two formed the thrash metal band Phantasm with guitarist Rodney Nicholson and several other musicians, briefly including Dark Angel drummer Gene Hoglan. Phantasm released a demo but never recorded a proper album, and disbanded in 1988 due to disagreements between members. In 2001, the thrash label Deep Six Records released the "Wreckage" CD, packaging a remastered version of the band's demo of the same name with a live set from 1987.


title: Ron McGovney

text: McGovney ceased his professional career after the demise of Phantasm, but gave sporadic interviews and appeared at Metallica-related events. Phantasm discussed a possible reunion in 2007, but this ultimately failed to materialize.


title: Ron McGovney

text: He performed publicly for the first time in 23 years on December 10, 2011, playing two songs onstage with Metallica, Mustaine, and early studio guitarist Lloyd Grant at The Fillmore as a part of the celebrations surrounding the end of the group's third decade. Two years later, he joined Mustaine's band Megadeth onstage in Charlotte, North Carolina, on December 5, 2013, sharing the lead vocal on a cover version of Thin Lizzy's "Cold Sweat".


title: Ron McGovney

text: McGovney has said that, although his time in Metallica came to an acrimonious end, he now gets along with his former bandmates and speculates that, given his disposition and skill-set, he might have been better able to contribute to the band had he served as road manager rather than bass guitarist.


title: Sea snake

text: Sea snakes, or coral reef snakes, are elapid snakes that inhabit marine environments for most or all of their lives. They belong to two subfamilies, Hydrophiinae and Laticaudinae. Hydrophiinae also includes Australasian terrestrial snakes, whereas Laticaudinae only includes the sea kraits ("Laticauda"), of which three species are found exclusively in freshwater. If these three freshwater species are excluded, there are 69 species of sea snakes divided between seven genera.


title: Sea snake

text: Most sea snakes are venomous, except the genus "Emydocephalus", which feeds almost exclusively on fish eggs. Sea snakes are extensively adapted to a fully aquatic life and are unable to move on land, except for the sea kraits, which have limited land movement. They are found in warm coastal waters from the Indian Ocean to the Pacific and are closely related to venomous terrestrial snakes in Australia.


title: Sea snake

text: All sea snakes have paddle-like tails and many have laterally compressed bodies that give them an eel-like appearance. Unlike fish, they do not have gills and must surface regularly to breathe. Along with whales, they are among the most completely aquatic of all extant air-breathing vertebrates. Among this group are species with some of the most potent venoms of all snakes. Some have gentle dispositions and bite only when provoked, while others are much more aggressive.


title: Sea snake

text: The majority of adult sea snakes species grow to between in length, with the largest, "Hydrophis spiralis", reaching a maximum of . Their eyes are relatively small with a round pupil and most have nostrils located dorsally. The skulls do not differ significantly from those of terrestrial elapids, although their dentition is relatively primitive with short fangs and (with the exception of "Emydocephalus") as many as 18 smaller teeth behind them on the maxilla.


title: Sea snake

text: Most sea snakes are completely aquatic and have adapted to sea environments in many ways, the most characteristic of which is a paddle-like tail that has improved their swimming ability. To a varying degree, the bodies of many species are laterally compressed, especially in the pelagic species. This has often caused the ventral scales to become reduced in size, even difficult to distinguish from the adjoining scales. Their lack of ventral scales means they have become virtually helpless on land, but as they live out their entire lifecycles at sea, they have no need to leave the water.


title: Sea snake

text: The only genus that has retained the enlarged ventral scales is the sea kraits, "Laticauda", with only five species. These snakes are considered to be more primitive, as they still spend much of their time on land, where their ventral scales afford them the necessary grip. "Laticauda" species are also the only sea snakes with internasal scales; that is, their nostrils are not located dorsally.


title: Sea snake

text: Since a snake's tongue can fulfill its olfactory function more easily under water, its action is short compared to that of terrestrial snake species. Only the forked tips protrude from the mouth through a divided notch in the middle of the rostral scale. The nostrils have valves consisting of a specialized spongy tissue to exclude water, and the windpipe can be drawn up to where the short nasal passage opens into the roof of the mouth. This is an important adaptation for an animal that must surface to breathe, but may have its head partially submerged when doing so. The lung has become very large and extends almost the entire length of the body, although the rear portion is thought to have developed to aid buoyancy rather than to exchange gases. The extended lung possibly also serves to store air for dives.


title: Sea snake

text: Most species of sea snakes are able to respire through the top of their skin. This is unusual for reptiles, because their skin is thick and scaly, but experiments with the black-and-yellow sea snake, "Hydrophis platurus" (a pelagic species), have shown this species can satisfy about 25% of its oxygen requirements in this manner, which allows for prolonged dives.


title: Sea snake

text: Like other land animals that have adapted to life in a marine environment, sea snakes ingest considerably more salt than their terrestrial relatives through their diets, and when seawater is inadvertently swallowed. Because of this, a more effective means of regulating the salt concentration of their blood is required. In sea snakes, the posterior sublingual glands, located under and around the tongue sheath, allow them to expel salt with their tongue action.


title: Sea snake

text: Scalation among sea snakes is highly variable. As opposed to terrestrial snake species that have imbricate scales to protect against abrasion, the scales of most pelagic sea snakes do not overlap. Reef-dwelling species, such as "Aipysurus", do have imbricate scales to protect against the sharp coral. The scales themselves may be smooth, keeled, spiny, or granular, the latter often looking like warts. "Pelamis" has body scales that are "peg-like", while those on its tail are juxtaposed hexagonal plates.


title: Sea snake

text: Vision, chemoreception (tongue-flicking), and hearing are important senses for terrestrial snakes, but these stimuli become distorted in water. The poor visibility, chemical dilution, and limitation of ground-borne vibrations under water suggest that sea snakes and sea kraits may have unique sensory abilities to compensate for the relative lack of other sensory cues.


title: Sea snake

text: Relatively little is known about sea snake vision. A study of photoreceptors in the retina of spine-bellied, "Lapemis curtus," and horned, "Acalyptophis peronii", sea snakes found three classes of opsins all from cone cells. Despite the absence of rod cells in sea snake eyes, Simeos "et al." found the rhodopsin ("rh1"), the opsin of the rods, still expressed suggesting that in sea snakes some cones may be transmuted rods. Behavioural observations indicate that vision has a limited role for catching prey and mate selection, but sound vibrations and chemoreception may be important. One study identified small sensory organs on the head of "Lapemis curtus" similar to the mechanoreceptors in alligators and aquatic snake Acrochodus that are used to sense the movement of fish prey. Westhoff "et al." recorded auditory brain responses to vibration underwater in "Lapemis curtus", which are sensitive enough to detect movement in prey, but were not as sensitive as fish lateral line systems. Similarly, vision appears to be of limited importance for finding mates. Shine experimented with applying skin secretions (pheromones) to snake-like objects to see if male turtle-headed sea snakes, "Emydocephalus annulatus," are attracted to female pheromones. Shine found that although vision may be useful over short distances (less than ), pheromones are more important once the male comes in physical contact with an object.


title: Sea snake

text: The olive sea snake, "Aipysurus laevis", has been found to have photoreceptors in the skin of its tail, allowing it to detect light and presumably ensuring it is completely hidden, including its tail, inside coral holes during the day. While other species have not been tested, "A. laevis" possibly is not unique among sea snakes in this respect.


title: Sea snake

text: Other unique senses, such as electromagnetic reception and pressure detection, have been proposed for sea snakes, but scientific studies have yet to be performed to test these senses.


title: Sea snake

text: Sea snakes are mostly confined to the warm tropical waters of the Indian Ocean and the western Pacific Ocean, with a few species found well out into Oceania. The geographic range of one species, "Pelamis platurus", is wider than that of any other reptile species, except for a few species of sea turtles. It extends from the east coast of Africa, from Djibouti in the north to Cape Town in the south, across the Indian Ocean, the Pacific, south as far as the northern coast of New Zealand, all the way to the western coast of the Americas, where it occurs from northern Peru in the south (including the Galápagos Islands) to the Gulf of California in the north. Isolated specimens have been found as far north as San Diego and Oxnard in the United States.


title: Sea snake

text: Sea snakes do not occur in the Atlantic Ocean. "Pelamis" possibly would be found there were it not for the cold currents off Namibia and western South Africa that keep it from crossing into the eastern South Atlantic, or south of 5°S latitude along the South American west coast. Sea snakes do not occur in the Red Sea, believed to be due to its increased salinity, so no danger exists of them crossing through the Suez Canal. A lack of salinity is also thought to be the reason why "Pelamis" has not crossed into the Caribbean via the Panama Canal.


title: Sea snake

text: Despite their marine adaptations, most sea snakes prefer shallow waters near land, around islands, and especially somewhat sheltered waters, as well as near estuaries. They may swim up rivers and have been reported as far as from the sea. Others, such as "P. platurus", are pelagic and are found in drift lines, slicks of floating debris brought together by surface currents. Some sea snakes inhabit mangrove swamps and similar brackishwater habitats, and two landlocked freshwater forms are found: "Hydrophis semperi" occurs in Lake Taal in the Philippines, and "Laticauda crockeri" in Lake Te Nggano on Rennell Island in the Solomon Islands.


title: Sea snake

text: Sea snakes are generally reluctant to bite, and are usually considered to be mild-tempered, although variation is seen among species and individuals. Some species, such as "P. platurus", which feed by simply gulping down their prey, are more likely to bite when provoked because they seem to use their venom more for defense. Others, such as "Laticauda" spp., use their venom for prey immobilization. Sea snakes are often handled without concern by local fishermen who unravel and toss them back into the water barehanded, usually without getting bitten, when the snakes frequently become entangled in fishing nets. Species reported as much more aggressive include "Aipysurus laevis", "Astrotia stokesii", "Enhydrina schistosa", "Enhydrina zweifeli", and "Hydrophis ornatus".


title: Sea snake

text: On land, their movements become very erratic. They crawl awkwardly in these situations and can become quite aggressive, striking wildly at anything that moves, although they are unable to coil and strike in the manner of terrestrial snakes.


title: Sea snake

text: Sea snakes appear to be active both day and night. In the morning, and sometimes late in the afternoon, they can be seen at the surface basking in the sunlight, and they dive when disturbed. They have been reported swimming at depths over , and can remain submerged for as long as a few hours, possibly depending on temperature and degree of activity.


title: Sea snake

text: Sea snakes have been sighted in huge numbers. For example, in 1932, a steamer in the Strait of Malacca, off the coast of Malaysia, reported sighting "millions" of "Astrotia stokesii", a relative of "Pelamis"; these reportedly formed a line of snakes wide and long. The cause of this phenomenon is unknown, although it likely has to do with reproduction. They can sometimes be seen swimming in schools of several hundred, and many dead specimens have been found on beaches after typhoons.


title: Sea snake

text: They feed on small fish and occasionally young octopus. They are often associated with the sea snake barnacle ("Platylepas ophiophila"), which attaches to their skin.


title: Sea snake

text: Except for a single genus, all sea snakes are ovoviviparous; the young are born alive in the water where they live their entire lives. In some species, the young are quite large, up to half as long as the mother. The one exception is the genus "Laticauda", which is oviparous; its five species all lay their eggs on land.


title: Sea snake

text: Like their relatives in the family Elapidae, the majority of the sea snakes are highly venomous, but rarely inject it when biting, so such damage to humans seems nonexistent or trivial. For example, "Hydrophis platurus" has a venom more potent than any terrestrial snake species in Costa Rica based on LD, but despite its abundance in the waters off its western coast, few human fatalities have been reported. The death of a trawler fisherman in Australian waters during 2018 was reported to be the region's first sea snake fatality since a pearl diver was killed in 1935.


title: Sea snake

text: Bites in which envenomation does occur are usually painless and may not even be noticed when contact is made. Teeth may remain in the wound. Usually, little or no swelling occurs, and rarely are any nearby lymph nodes affected. The most important symptoms are rhabdomyolysis (rapid breakdown of skeletal muscle tissue) and paralysis. Early symptoms include headache, a thick-feeling tongue, thirst, sweating, and vomiting. The venom is very slow acting and symptoms that happen from little as 30 minutes to several hours after the bite include generalized aching, stiffness, and tenderness of muscles all over the body. Passive stretching of the muscles is also painful, and trismus, which is similar to tetanus, is common. This is followed later on by symptoms typical of other elapid envenomations, a progressive flaccid paralysis, starting with ptosis and paralysis of voluntary muscles. Paralysis of muscles involved in swallowing and respiration can be fatal.


title: Sea snake

text: Vick "et al" (1975) estimated that the LD50 of three sea snake venoms ("H. platurus", "L. semifasciata" and "L. laticaudata") for a 70 kg human range from 7.7 to 21 mg. Data from the only sea snake venom conducted in monkeys at that time suggested that primates were slightly more resistant to the venom effects on a dose response basis than mice. In this regard, recall the recent report by Ishikawa "et al" (1985) indicating a substantially lower binding affinity between sea snake neurotoxin and human and chimpanzee AChR's compared to that in other animals. In humans, the venom targets appear mainly to be the cell walls of voluntary (skeletal) muscles and distal tubular portions of the kidney including the loop of Henle, the second convoluted tubule and the collecting tubules. Sitprija "et al" (1973) found evidence of tubular necrosis throughout all portions of the renal tubules in two patients severely envenomated by sea snakes. Sea snake venoms in humans are thus more often myotoxic and/or nephrotoxic rather than neurotoxic.


title: Sea snake

text: Sea snakes were at first regarded as a unified and separate family, the Hydrophiidae, that later came to comprise two subfamilies: the Hydrophiinae, or true/aquatic sea snakes (now 6 genera with 64 species), and the more primitive Laticaudinae, or sea kraits (one genus, "Laticauda", with eight species). Eventually, as just how closely related the sea snakes are to the elapids became clear, the taxonomic situation became less well-defined. Some taxonomists responded by moving the sea snakes to the Elapidae. Most taxonomists now place the sea snakes in the elapid subfamilies Hydrophiinae and Laticaudinae, although the latter may be omitted if "Laticauda" is included in the Hydrophiinae. Unlike the traditional Hydrophiinae, the Hydrophiinae as currently seen also includes Australasian terrestrial elapids.


title: Sea snake

text: Molecular data studies suggest all three monotypic semiaquatic genera ("Ephalophis", "Parahydrophis" and "Hydrelaps") are early diverging lineages.


title: Sea snake

text: At best, sea snakes make difficult captives. Ditmars (1933) described them as nervous and delicate captives that usually refuse to eat, preferring only to hide in the darkest corner of the tank. Over 50 years later, Mehrtens wrote in 1987 that although they were rarely displayed in Western zoological parks, some species were regularly on display in Japanese aquariums. The available food supply limits the number of species that can be kept in captivity, since some have diets that are too specialized. Also, some species appear intolerant of handling, or even being removed from the water. Regarding their requirements in captivity, the "Laticauda" species need to be able to exit the water somewhere at about , along with a submerged shelter. Species that have done relatively well in captivity include the ringed sea snake, "Hydrophis cyanocinctus", which feeds on fish and eels in particular. "Pelamis platurus" has done especially well in captivity, accepting small fish, including goldfish. Housing them in round tanks, or in rectangular tanks with well-rounded corners, prevents snakes from damaging their snouts on the sides.


title: Sea snake

text: Most sea snakes are not on the CITES protection lists. One species, "Laticauda crockeri", is classified as vulnerable. Several species of "Aipysurus" are listed with conservation status of greater concern, the Timor species "A. fuscus" is known to be endangered, and two others found in seas north of Australia, the leaf-scaled "A. foliosquama" and short-nosed "A. apraefrontalis", are classified as critically endangered according to the IUCN Red List of Threatened Species.


title: Instrument landing system

text: In aviation, the instrument landing system (ILS) is a precision radio navigation system that provides short-range guidance to aircraft to allow them to approach a runway at night or in bad weather. In its original form, it allows an aircraft to approach until it is over the ground, within a of the runway. At that point the runway should be visible to the pilot; if it is not, they perform a missed approach. Bringing the aircraft this close to the runway dramatically increases the range of weather conditions in which a safe landing can be made. Other versions of the system, or "categories", have further reduced the minimum altitudes, runway visual ranges (RVRs), and transmitter and monitoring configurations designed depending on the normal expected weather patterns and airport safety requirements.


title: Instrument landing system

text: ILS uses two directional radio signals, the "localizer" (108 to 112 MHz frequency), which provides horizontal guidance, and the "glideslope" (329.15 to 335 MHz frequency) for vertical guidance. The relationship between the aircraft's position and these signals is displayed on an aircraft instrument, often additional pointers in the attitude indicator. The pilot attempts to manoeuvre the aircraft to keep the indicators centered while they approach the runway to the decision height. Optional "Marker Beacon(s)" provide distance information as the approach proceeds, including the "middle marker" (MM), placed close to the position of the (CAT 1) decision height. Markers are largely being phased out and replaced by distance measuring equipment (DME). The ILS usually includes high-intensity lighting at the end of the runways to help the pilot locate the runway and transition from the approach to a visual landing.


title: Instrument landing system

text: A number of radio-based landing systems were developed between the 1920s and 1940s, notably the Lorenz beam which saw relatively wide use in Europe prior to the war. The US-developed SCS-51 system was more accurate while also adding vertical guidance. Many sets were installed at airbases in the United Kingdom during World War II, which led to it being selected as the international standard after the formation of the International Civil Aviation Organization (ICAO) in 1947. Several competing landing systems have been developed, including the radar-based ground-controlled approach (GCA) and the more recent microwave landing system (MLS), but few of these systems have been deployed. ILS remains a widespread standard to this day.


title: Instrument landing system

text: The introduction of precision approaches using global navigation satellite systems (GNSSs) instead of requiring expensive airport infrastructure is leading to the replacement of ILS. Providing the required accuracy with GNSS normally requires only a low-power omnidirectional augmentation signal to be broadcast from the airport, which is dramatically less expensive than the multiple, large and powerful transmitters required for a full ILS implementation. By 2015, the number of US airports supporting ILS-like LPV approaches exceeded the number of ILS installations, and this is expected to lead to the eventual removal of ILS at most airports.


title: Instrument landing system

text: An "instrument landing system" operates as a ground-based instrument approach system that provides precision lateral and vertical guidance to an aircraft approaching and landing on a runway, using a combination of radio signals and, in many cases, high-intensity lighting arrays to enable a safe landing during instrument meteorological conditions (IMC), such as low ceilings or reduced visibility due to fog, rain, or blowing snow.


title: Instrument landing system

text: Previous blind landing radio aids typically took the form of "beam" systems of various types. These normally consisted of a radio transmitter that was connected to a motorized switch to produce a pattern of Morse code dots and dashes. The switch also controlled which of two directional antennae the signal was sent to. The resulting signal sent into the air consists of dots sent to one side of the runway and dashes to the other. The beams were wide enough so they overlapped in the center.


title: Instrument landing system

text: To use the system an aircraft only needed a conventional radio receiver. As they approached the airport they would tune in the signal and listen to it in their headphones. They would hear dots and dashes (Morse code "A" or "N"), if they were to the side of the runway, or if they were properly aligned, the two mixed together to produce a steady tone, the "equisignal". The accuracy of this measurement was highly dependent on the skill of the operator, listening to the signal on earphones in a noisy aircraft often whilst communicating with the tower at the same time.


title: Instrument landing system

text: Accuracy of the system was normally on the order of 3 degrees in azimuth. While this was useful for bringing the aircraft onto the direction of the runway, it was not accurate enough to safely bring the aircraft to visual range in bad weather; the radio course beams were used only for lateral guidance, and the system was not enough on its own to perform landings in heavy rain or fog. Nevertheless, the final decision to land was made at only from the airport.


title: Instrument landing system

text: The ILS, developed just prior to the start of World War II, used a more complex system of signals and an antenna array to achieve higher accuracy. This requires significantly more complexity in the ground station and transmitters, with the advantage that the signals can be accurately decoded in the aircraft using simple electronics and displayed directly on analog instruments. The instruments can be placed in front of the pilot, eliminating the need for a radio operator to continually monitor the signals and relay the results to the pilot over the intercom.


title: Instrument landing system

text: Key to its operation is a concept known as the amplitude modulation index, a measure of how strongly the amplitude modulation is applied to the carrier frequency. In the earlier beam systems, the signal was turned on and off entirely, corresponding to a modulation index of 100%. The determination of angle within the beam is based on the comparison of the audible strength of the two signals.


title: Instrument landing system

text: In ILS, a more complex system of signals and antennas varies the modulation of two signals across the entire width of the beam pattern. The system relies on the use of sidebands, secondary frequencies that are created when two different signals are mixed. For instance, if one takes a radio frequency signal at 10 MHz and mixes that with an audible tone at 2500 Hz, four signals will be produced, at the original signals’ frequencies of 2500 and 10000000 hertz, and sidebands 9997500 and 10002500 hertz. The original 2500 Hz signal's frequency is too low to travel far from an antenna, but the other three signals are all radio frequency and can be effectively transmitted.


title: Instrument landing system

text: ILS starts by mixing two modulating signals to the carrier, one at 90 Hz and another at 150. This creates a signal with five radio frequencies in total, the carrier and four sidebands. This combined signal, known as the CSB for "carrier and sidebands", is sent out evenly from an antenna array. The CSB is also sent into a circuit that suppresses the original carrier, leaving only the four sideband signals. This signal, known as SBO for "sidebands only", is also sent to the antenna array.


title: Instrument landing system

text: For lateral guidance, known as the "localizer", the antenna is normally placed centrally at the far end of the runway and consists of multiple antennas in an array normally about the same width of the runway. Each individual antenna has a particular phase shift and power level applied only to the SBO signal such that the resulting signal is retarded 90 degrees on the left side of the runway and advanced 90 degrees on the right. Additionally, the 150 Hz signal is inverted on one side of the pattern, another 180 degree shift. Due to the way the signals mix in space the SBO signals destructively interfere with and almost eliminate each other along the centerline, leaving just the CSB signal predominating. At any other location, on either side of the centerline, the SBO and CSB signals combine in different ways so that one modulating signal predominates.


title: Instrument landing system

text: A receiver in front of the array will receive both of these signals mixed together. Using simple electronic filters, the original carrier and two sidebands can be separated and demodulated to extract the original amplitude-modulated 90 and 150 Hz signals. These are then averaged to produce two direct current (DC) signals. Each of these signals represents not the strength of the original signal, but the strength of the modulation relative to the carrier, which varies across the beam pattern. This has the great advantage that the measurement of angle is independent of range.


title: Instrument landing system

text: The two DC signals are then sent to a conventional voltmeter, with the 90 Hz output pulling the needle right and the other left. Along the centreline the two modulating tones of the sidebands will be cancelled out and both voltages will be zero, leaving the needle centered in the display. If the aircraft is far to the left, the 90 Hz signal will produce a strong DC voltage (predominates), and the 150 Hz signal is minimised, pulling the needle all the way to the right. This means the voltmeter directly displays both the direction and magnitude of the turn needed to bring the aircraft back to the runway centreline. As the measurement compares different parts of a single signal entirely in electronics, it provides angular resolution of less than a degree, and allows the construction of a precision approach.


title: Instrument landing system

text: Although the encoding scheme is complex, and requires a considerable amount of ground equipment, the resulting signal is both far more accurate than the older beam-based systems and is far more resistant to common forms of interference. For instance, static in the signal will affect both sub-signals equally, so it will have no effect on the result. Similarly, changes in overall signal strength as the aircraft approaches the runway, or changes due to fading, will have little effect on the resulting measurement because they would normally affect both channels equally. The system is subject to multipath distortion effects due to the use of multiple frequencies, but because those effects are dependent on the terrain, they are generally fixed in location and can be accounted for through adjustments in the antenna or phase shifters.


title: Instrument landing system

text: Additionally, because it is the encoding of the signal within the beam that contains the angle information, not the strength of the beam, the signal does not have to be tightly focussed in space. In the older beam systems, the accuracy of the equisignal area was a function of the pattern of the two directional signals, which demanded that they be relatively narrow. The ILS pattern can be much wider. ILS installations are normally required to be usable within 10 degrees on either side of the runway centerline at , and 35 degrees on either side at . This allows for a wide variety of approach paths.


title: Instrument landing system

text: The "glideslope" works in the same general fashion as the localizer and uses the same encoding, but is normally transmitted to produce a centerline at an angle of 3 degrees above horizontal from an antenna beside the runway instead of the end. The only difference between the signals is that the localizer is transmitted using lower carrier frequencies, using 40 selected channels between 108.10 MHz and 111.95 MHz, whereas the glideslope has a corresponding set of 40 channels between 328.6 and 335.4 MHz. The higher frequencies generally result in the glideslope radiating antennas being smaller. The channel pairs are not linear; localizer channel 1 is at 108.10 and paired with glideslope at 334.70, whereas channel two is 108.15 and 334.55. There are gaps and jumps through both bands.


title: Instrument landing system

text: Many illustrations of the ILS concept often show the system operating more similarly to beam systems with the 90 Hz signal on one side and the 150 on the other. These illustrations are inaccurate; both signals are radiated across the entire beam pattern, it is their relative difference in the depth of modulation (DDM) that changes dependent upon the position of the approaching aircraft.


title: Instrument landing system

text: An instrument approach procedure chart (or 'approach plate') is published for each ILS approach to provide the information needed to fly an ILS approach during instrument flight rules (IFR) operations. A chart includes the radio frequencies used by the ILS components or navaids and the prescribed minimum visibility requirements.


title: Instrument landing system

text: An aircraft approaching a runway is guided by the ILS receivers in the aircraft by performing modulation depth comparisons. Many aircraft can route signals into the autopilot to fly the approach automatically. An ILS consists of two independent sub-systems. The localizer provides lateral guidance; the glide slope provides vertical guidance.


title: Instrument landing system

text: A localizer (LOC, or LLZ until ICAO standardisation) is an antenna array normally located beyond the departure end of the runway and generally consists of several pairs of directional antennas.


title: Instrument landing system

text: The localizer will allow the aircraft to turn and match the aircraft with the runway. After that, the pilots will activate approach phase (APP).


title: Instrument landing system

text: The pilot controls the aircraft so that the glide slope indicator remains centered on the display to ensure the aircraft is following the glide path of approximately 3° above horizontal (ground level) to remain above obstructions and reach the runway at the proper touchdown point (i.e. it provides vertical guidance).


title: Instrument landing system

text: Due to the complexity of ILS localizer and glide slope systems, there are some limitations. Localizer systems are sensitive to obstructions in the signal broadcast area, such as large buildings or hangars. Glide slope systems are also limited by the terrain in front of the glide slope antennas. If terrain is sloping or uneven, reflections can create an uneven glidepath, causing unwanted needle deflections. Additionally, since the ILS signals are pointed in one direction by the positioning of the arrays, glide slope supports only straight-line approaches with a constant angle of descent. Installation of an ILS can be costly because of siting criteria and the complexity of the antenna system.


title: Instrument landing system

text: ILS critical areas and ILS sensitive areas are established to avoid hazardous reflections that would affect the radiated signal. The location of these critical areas can prevent aircraft from using certain taxiways leading to delays in takeoffs, increased hold times, and increased separation between aircraft.


title: Instrument landing system

text: In addition to the previously mentioned navigational signals, the localizer provides for ILS facility identification by periodically transmitting a 1,020 Hz Morse code identification signal. For example, the ILS for runway 4R at John F. Kennedy International Airport transmits IJFK to identify itself, while runway 4L is known as IHIQ. This lets users know the facility is operating normally and that they are tuned to the correct ILS. The glide slope station transmits no identification signal, so ILS equipment relies on the localizer for identification.


title: Instrument landing system

text: It is essential that any failure of the ILS to provide safe guidance be detected immediately by the pilot. To achieve this, monitors continually assess the vital characteristics of the transmissions. If any significant deviation beyond strict limits is detected, either the ILS is automatically switched off or the navigation and identification components are removed from the carrier. Either of these actions will activate an indication ('failure flag') on the instruments of an aircraft using the ILS.


title: Instrument landing system

text: Modern localizer antennas are highly directional. However, usage of older, less directional antennas allows a runway to have a non-precision approach called a "localizer back course". This lets aircraft land using the signal transmitted from the back of the localizer array. Highly directional antennas do not provide a sufficient signal to support a back course. In the United States, back course approaches are typically associated with Category I systems at smaller airports that do not have an ILS on both ends of the primary runway. Pilots flying a back course should disregard any glide slope indication.


title: Instrument landing system

text: On some installations, marker beacons operating at a carrier frequency of 75 MHz are provided. When the transmission from a marker beacon is received it activates an indicator on the pilot's instrument panel and the tone of the beacon is audible to the pilot. The distance from the runway at which this indication should be received is published in the documentation for that approach, together with the height at which the aircraft should be if correctly established on the ILS. This provides a check on the correct function of the glide slope. In modern ILS installations, a DME is installed, co-located with the ILS, to augment or replace marker beacons. A DME continuously displays the aircraft's distance to the runway.


title: Instrument landing system

text: Distance measuring equipment (DME) provides pilots with a slant range measurement of distance to the runway. DMEs are augmenting or replacing markers in many installations. The DME provides more accurate and continuous monitoring of correct progress on the ILS glide slope to the pilot, and does not require an installation outside the airport boundary. When used in conjunction with an ILS, the DME is often sited midway between the reciprocal runway thresholds with the internal delay modified so that one unit can provide distance information to either runway threshold. For approaches where a DME is specified in lieu of marker beacons, "DME required" is noted on the instrument approach procedure and the aircraft must have at least one operating DME unit, or an IFR-approved system using a GNSS (an RNAV system meeting TSO-C129/ -C145/-C146), to begin the approach.


title: Instrument landing system

text: Some installations include medium- or high-intensity approach light systems (abbreviated "ALS"). Most often, these are at larger airports but many small general aviation airports in the U.S. have approach lights to support their ILS installations and obtain low-visibility minimums. The ALS assists the pilot in transitioning from instrument to visual flight, and to align the aircraft visually with the runway centerline. Pilot observation of the approach lighting system at the Decision Altitude allows the pilot to continue descending towards the runway, even if the runway or runway lights cannot be seen, since the ALS counts as runway end environment. In the U.S., an ILS without approach lights may have CAT I ILS visibility minimums as low as (runway visual range of ) if the required obstacle clearance surfaces are clear of obstructions. Visibility minimums of (runway visual range of ) are possible with a CAT I ILS approach supported by a ALS, and visibility visual range is possible if the runway has high-intensity edge lights, touchdown zone and centerline lights, and an ALS that is at least long (see Table 3-3-1 "Minimum visibility values" in FAA Order 8260.3C). In effect, ALS extends the runway environment out towards the landing aircraft and allows low-visibility operations. CAT II and III ILS approaches generally require complex high-intensity approach light systems, while medium-intensity systems are usually paired with CAT I ILS approaches. At some non-towered airports, the pilot controls the lighting system; for example, the pilot can key the microphone seven times to turn on the lights on the high intensity, five times to medium intensity or three times for low intensity.


title: Instrument landing system

text: Once established on an approach, the pilot follows the ILS approach path indicated by the localizer and descends along the glide path to the decision height. This is the height at which the pilot must have adequate visual reference to the landing environment (e.g. approach or runway lighting) to decide whether to continue the descent to a landing; otherwise, the pilot must execute a missed approach procedure, then try the same approach again, try a different approach, or divert to another airport.


title: Instrument landing system

text: Smaller aircraft generally are equipped to fly only a CAT I ILS. On larger aircraft, these approaches typically are controlled by the flight control system with the flight crew providing supervision. CAT I relies only on altimeter indications for decision height, whereas CAT II and CAT III approaches use radio altimeter (RA) to determine decision height.


title: Instrument landing system

text: An ILS must shut down upon internal detection of a fault condition. Higher categories require shorter response times; therefore, ILS equipment is required to shut down more quickly. For example, a CAT I localizer must shut down within 10 seconds of detecting a fault, but a CAT III localizer must shut down in less than 2 seconds.


title: Instrument landing system

text: In contrast to other operations, CAT III weather minima do not provide sufficient visual references to allow a manual landing to be made. CAT IIIb minima depend on roll-out control and redundancy of the autopilot, because they give only enough time for the pilot to decide whether the aircraft will land in the touchdown zone (basically CAT IIIa) and to ensure safety during rollout (basically CAT IIIb). Therefore, an automatic landing system is mandatory to perform Category III operations. Its reliability must be sufficient to control the aircraft to touchdown in CAT IIIa operations and through rollout to a safe taxi speed in CAT IIIb (and CAT IIIc when authorized). However, special approval has been granted to some operators for hand-flown CAT III approaches using a head-up display (HUD) guidance that provides the pilot with an image viewed through the windshield with eyes focused at infinity, of necessary electronic guidance to land the airplane with no true outside visual references.


title: Instrument landing system

text: In the United States, airports with CAT III approaches have listings for CAT IIIa and IIIb or just CAT III on the instrument approach plate (U.S. Terminal Procedures). CAT IIIb RVR minimums are limited by the runway/taxiway lighting and support facilities, and are consistent with the airport surface movement guidance control system (SMGCS) plan. Operations below 600 ft RVR require taxiway centerline lights and taxiway red stop bar lights. If the CAT IIIb RVR minimums on a runway end are , which is a common figure in the U.S., ILS approaches to that runway end with RVR below qualify as CAT IIIc and require special taxi procedures, lighting, and approval conditions to permit the landings. FAA Order 8400.13D limits CAT III to 300 ft RVR or better. Order 8400.13D (2009) allows "special authorization CAT II" approaches to runways without ALSF-2 approach lights and/or touchdown zone/centerline lights, which has expanded the number of potential CAT II runways.


title: Instrument landing system

text: In each case, a suitably equipped aircraft and appropriately qualified crew are required. For example, CAT IIIb requires a fail-operational system, along with a crew who are qualified and current, while CAT I does not. A HUD that allows the pilot to perform aircraft maneuvers rather than an automatic system is considered as fail-operational. A HUD allows the flight crew to fly the aircraft using the guidance cues from the ILS sensors such that if a safe landing is in doubt, the crew can respond in an appropriate and timely manner. HUD is becoming increasingly popular with "feeder" airlines and most manufacturers of regional jets are now offering HUDs as either standard or optional equipment. A HUD can provide capability to take off in low visibility.


title: Instrument landing system

text: Some commercial aircraft are equipped with automatic landing systems that allow the aircraft to land without transitioning from instruments to visual conditions for a normal landing. Such autoland operations require specialized equipment, procedures and training, and involve the aircraft, airport, and the crew. Autoland is the only way some major airports such as Charles de Gaulle Airport remain operational every day of the year. Some modern aircraft are equipped with enhanced flight vision systems based on infrared sensors, that provide a day-like visual environment and allow operations in conditions and at airports that would otherwise not be suitable for a landing. Commercial aircraft also frequently use such equipment for takeoffs when "takeoff minima" are not met.


title: Instrument landing system

text: For both automatic and HUD landing systems, the equipment requires special approval for its design and also for each individual installation. The design takes into consideration additional safety requirements for operating an aircraft close to the ground and the ability of the flight crew to react to a system anomaly. The equipment also has additional maintenance requirements to ensure that it is capable of supporting reduced visibility operations.


title: Instrument landing system

text: Of course nearly all of this pilot training and qualification work is done in simulators with various degrees of fidelity.


title: Instrument landing system

text: At a controlled airport, air traffic control will direct aircraft to the localizer course via assigned headings, making sure aircraft do not get too close to each other (maintain separation), but also avoiding delay as much as possible. Several aircraft can be on the ILS at the same time, several miles apart. An aircraft that has turned onto the inbound heading and is within two and a half degrees of the localizer course (half scale deflection or less shown by the course deviation indicator) is said to be "established" on the approach. Typically, an aircraft is established by at least prior to the final approach fix (glideslope intercept at the specified altitude).


title: Instrument landing system

text: Aircraft deviation from the optimal path is indicated to the flight crew by means of a display dial (a carryover from when an analog meter movement indicated deviation from the course line via voltages sent from the ILS receiver).


title: Instrument landing system

text: The output from the ILS receiver goes to the display system (head-down display and head-up display if installed) and may go to a Flight Control Computer. An aircraft landing procedure can be either "coupled" where the autopilot or Flight Control Computer directly flies the aircraft and the flight crew monitor the operation, or "uncoupled" where the flight crew flies the aircraft manually to keep the localizer and glideslope indicators centered.


title: Instrument landing system

text: Tests of the ILS began in 1929 in the United States, with Jimmy Doolittle becoming the first pilot to take off, fly and land an airplane using instruments alone, without a view outside the cockpit. A basic system, fully operative, was introduced in 1932 at Berlin-Tempelhof Central Airport (Germany) named LFF or "Lorenz beam" due its inventor, the C. Lorenz AG company. The Civil Aeronautics Board (CAB) of the United States authorized installation of the system in 1941 at six locations. The first landing of a scheduled U.S. passenger airliner using ILS was on January 26, 1938, when a Pennsylvania Central Airlines Boeing 247D flew from Washington, D.C., to Pittsburgh, Pennsylvania, and landed in a snowstorm using only the Instrument Landing System. The first fully automatic landing using ILS occurred in March 1964 at Bedford Airport in the UK.


title: Instrument landing system

text: The instrument landing systems market revenue was US$1,215 Million in 2019, and is expected to reach US$1,667 Million in 2025, with a CAGR of 5.41% during 2020-2025 even with the negative effects of the COVID-19 pandemic.


title: Instrument landing system

text: The advent of the Global Positioning System (GPS) provides an alternative source of approach guidance for aircraft. In the US, the Wide Area Augmentation System (WAAS) has been available in many regions to provide precision guidance to Category I standards since 2007. The equivalent European Geostationary Navigation Overlay Service (EGNOS) was certified for use in safety of life applications in March 2011. As such, the number of Cat I ILS installations may be reduced, however there are no plans in the United States to phase out any Cat II or Cat III systems.


title: Instrument landing system

text: Local Area Augmentation System (LAAS) is under development to provide for Category III minimums or lower. The FAA Ground-Based Augmentation System (GBAS) office is currently working with the industry in anticipation of the certification of the first GBAS ground stations in Memphis, TN; Sydney, Australia; Bremen, Germany; Spain; and Newark, NJ. All four countries have installed GBAS ground stations and are involved in technical and operational evaluation activities.


title: Instrument landing system

text: The Honeywell and FAA team obtained System Design Approval of the world's first non-federal U.S. approval for LAAS Category I at Newark Liberty International Airport, operations in September 2009 and Operational Approval on September 28, 2012.


title: Instrument landing system

text: In Norway, a D-GPS based landing system, called SCAT-I, is in operation on some short runway airports.


title: Go Set a Watchman

text: Go Set a Watchman is a novel written by Harper Lee before her Pulitzer Prize-winning "To Kill a Mockingbird" (1960), her only other published novel. Although "Go Set a Watchman" was initially promoted as a sequel by its publisher, it is now accepted that it was a first draft of "To Kill a Mockingbird" with many passages in that book being used again.


title: Go Set a Watchman

text: The title comes from Isaiah 21:6: "For thus hath the Lord said unto me, Go, set a watchman, let him declare what he seeth", which is quoted in the book's seventh chapter by Mr. Stone, the minister character. It alludes to Jean Louise Finch's view of her father, Atticus Finch, as the moral compass ("watchman") of Maycomb, and has a theme of disillusionment, as she discovers the extent of the bigotry in her home community. "Go Set a Watchman" tackles the racial tensions brewing in the South in the 1950s and delves into the complex relationship between father and daughter. It includes treatments of many of the characters who appear in "To Kill a Mockingbird".


title: Go Set a Watchman

text: A significant controversy around the decision to publish "Go Set a Watchman" centered around the allegations that 89-year-old Lee was taken advantage of and was pressured into allowing publication against her previously stated intentions. Later, when it was realized that the book was an early draft as opposed to a distinct sequel, it was questioned why the novel had been published without any context.


title: Go Set a Watchman

text: HarperCollins, United States, and William Heinemann, United Kingdom, published "Go Set a Watchman" on July 14, 2015. The book's unexpected discovery, decades after it was written, and the status of the author's only other book as an American classic, caused its publication to be highly anticipated. Amazon stated that it was their "most pre-ordered book" since "Harry Potter and the Deathly Hallows" in 2007, and stores arranged all-night openings beginning at midnight to cope with expected demand.


title: Go Set a Watchman

text: Jean Louise "Scout" Finch, 26 and single, returns from New York to her hometown Maycomb, Alabama, for her annual fortnight-long visit to her father Atticus, a lawyer and former state legislator. Jack, her uncle and a retired doctor, is Jean Louise’s mentor. Atticus’ sister and Jean Louise’s aunt Alexandra has moved in with Atticus to help him around the house after his housekeeper Calpurnia retired. Jean Louise's brother, Jeremy "Jem" Finch, has died of the same heart condition which killed their mother. Upon her arrival in Maycomb, she is met by her childhood sweetheart Henry "Hank" Clinton, who works for Atticus. When returning from Finch's Landing, Jean Louise and Henry are passed by a car full of black men travelling at a dangerously high speed; Henry mentions that the Black people in the county have money for cars but are without licenses and insurance.


title: Go Set a Watchman

text: The Supreme Court's decision in "Brown v. Board of Education" and the National Association for the Advancement of Colored People (NAACP) are introduced as sources of controversy in the community. Jean Louise finds a pamphlet titled "The Black Plague" among her father's papers. She follows him to a Citizens' Council meeting where Atticus introduces a man who delivers a racist speech. Jean Louise watches in secret from the balcony and is horrified. She is unable to forgive him for his behaviour and flees from the hall. After dreaming about Calpurnia, her family's black maid whom she sees as a mother figure, Jean Louise has breakfast with her father. They soon learn that Calpurnia's grandson killed a drunk pedestrian the previous night while speeding in his car. Atticus agrees to take the case in order to stop the NAACP from getting involved. Jean Louise visits Calpurnia and is treated politely but coldly, causing her to leave, devastated.


title: Go Set a Watchman

text: While at lunch, Jean Louise wants to know why Atticus was at the meeting. Uncle Jack tells her that Atticus has not suddenly become a racist but he is trying to slow down federal government intervention into state politics. Her uncle lectures her on the complexity of history, race, and politics in the South in an attempt to get Jean Louise to come to a conclusion, which she struggles to grasp. She then has a flashback to when she was a teenager and recalls an incident where Atticus planted the seed for an idea in Henry's brain, then let him come to the right conclusion on his own. Jean Louise tells Henry that she does not love him and will never marry him. She expresses her disgust at seeing him with her father at the council meeting. Henry explains that sometimes people have to do things they don't want to do. Henry then defends his own case by saying that the reason that he is still part of the Citizens' Council is because he wants to use his intelligence to make an impact on his hometown of Maycomb and to make money to raise a family. She screams that she could never live with a hypocrite, only to notice that Atticus is standing behind them, smiling.


title: Go Set a Watchman

text: During a discussion with his daughter, Atticus argues that the blacks of the South are not ready for full civil rights, and the Supreme Court's decision was unconstitutional and irresponsible. Although Jean Louise agrees that the South is not ready to be fully integrated, she says the court was pushed into a corner by the NAACP and had to act. She is confused and devastated by her father's positions as they are contrary to everything he has ever taught her. She returns to the family home furious and packs her things. As she is about to leave town, her uncle comes home. She angrily complains to him, and her uncle slaps her across the face. He tells her to think of all the things that have happened over the past two days and how she has processed them. When she says she can now stand them, he tells her it is bearable because she is her own person. He says that at one point she had fastened her conscience to her father's, assuming that her answers would always be his answers. Her uncle tells her that Atticus was letting her break her idols so that she could reduce him to the status of a human being.


title: Go Set a Watchman

text: Jean Louise returns to the office and makes a date with Henry for the evening. She reflects that Maycomb has taught him things she had never known and rendered her useless to him except as his oldest friend. She goes to apologize to Atticus, but he tells her how proud of her he is. He hoped that she would stand for what she thinks is right. She reflects that she did not want her world disturbed but that she tried to crush the man who is trying to preserve it for her. Telling him that she loves him very much as she follows him to the car, she silently welcomes him to the human race. For the first time, she sees him as just a man.


title: Go Set a Watchman

text: Initially, "Go Set a Watchman" was promoted by its publisher, and described in media reports, as a sequel to Lee's best-selling novel, "To Kill a Mockingbird", which was published in 1960, but it is actually the first draft of that novel. The novel was finished in 1957 and purchased by the J.B. Lippincott Company. Lee's editor, Tay Hohoff was impressed by elements of the story, and stated that "the spark of the true writer flashed in every line", but she thought that it was by no means ready for publication, being, as she described it, "more a series of anecdotes than a fully conceived novel". In his "Times" article on Hohoff, Jonathan Mahler states that Hohoff thought the strongest aspect of Lee's novel was the flashback sequences featuring a young Scout, which is why she asked Lee to use those flashbacks as a basis for a new novel. Lee agreed, and "during the next couple of years, Hohoff led Lee from one draft to the next until the book finally achieved its finished form and was retitled "To Kill a Mockingbird"."


title: Go Set a Watchman

text: According to Mahler, "Ms. Hohoff also references a more detailed characterization of the development process, found in the Lippincott corporate history: 'After a couple of false starts, the story-line, interplay of characters, and fall of emphasis grew clearer, and with each revision—there were many minor changes as the story grew in strength and in her own vision of it—the true stature of the novel became evident.' (In 1978, Lippincott was acquired by Harper & Row, which became HarperCollins, publisher of "Watchman".)" Mahler remarks that "there appeared to be a natural give and take between author and editor. 'When she disagreed with a suggestion, we talked it out, sometimes for hours,' Ms. Hohoff wrote. 'And sometimes she came around to my way of thinking, sometimes I to hers, sometimes the discussion would open up an entirely new line of controversy.'"


title: Go Set a Watchman

text: Various theories have been offered as to why the initial characterization of Atticus as a segregationist was dropped in the later novel. Mahler suggests that it could have been Hohoff who inspired the change. Raised "in a multigenerational Quaker home near Prospect Park in Brooklyn, Hohoff attended a Quaker school, Brooklyn Friends. Such an upbringing suggests certain progressive values. But probably the clearest window into her state of mind when she was coaching Ms. Lee through the rewrite of "Mockingbird" is the book she was writing herself at the time: a biography of John Lovejoy Elliott, a social activist and humanist in early-20th-century New York who had committed his life to helping the city's underclass. The book, "A Ministry to Man", was published in 1959, one year before "Mockingbird"."


title: Go Set a Watchman

text: Michiko Kakutani made note of the changes between the two versions: "Some plot points that have become touchstones in "Mockingbird" are evident in the earlier "Watchman". Scout's older brother, Jem, vividly alive as a boy in "Mockingbird", is dead in "Watchman"; the trial of a black man accused of raping a young white woman ... is only a passing aside in "Watchman". (The trial results in a guilty verdict for the accused man, Tom Robinson, in "Mockingbird" but leads to an acquittal in "Watchman".)" She continues, "Students of writing will find "Watchman" fascinating for these reasons: How did a lumpy tale about a young woman's grief over her discovery of her father's bigoted views evolve into a classic coming-of-age story about two children and their devoted widower father? How did a distressing narrative filled with characters spouting hate speech (from the casually patronizing to the disgustingly grotesque—and presumably meant to capture the extreme prejudice that could exist in small towns in the Deep South in the 1950s) mutate into a redemptive novel associated with the civil rights movement, hailed, in the words of the former civil rights activist and congressman Andrew Young, for giving us 'a sense of emerging humanism and decency'?"


title: Go Set a Watchman

text: Kakutani also goes on to state that not only are characterizations and plot points different, the motivation behind the novel shifts as well: "Somewhere along the way, the overarching impulse behind the writing also seems to have changed. "Watchman" reads as if it were fueled by the alienation of a native daughter — who, like Lee, moved away from small-town Alabama to New York City — might feel upon returning home. It seems to want to document the worst in Maycomb in terms of racial and class prejudice, the people's enmity and hypocrisy and small-mindedness. At times, it also alarmingly suggests that the civil rights movement roiled things up, making people who "used to trust each other" now "watch each other like hawks".


title: Go Set a Watchman

text: According to Kakutani, ""Mockingbird", in contrast, represents a determined effort to see both the bad and the good in small-town life, the hatred and the humanity; it presents an idealized father-daughter relationship (which a relative in "Watchman" suggests has kept Jean Louise from fully becoming her own person) and views the past not as something lost but as a treasured memory. In a 1963 interview, Lee, whose own hometown is Monroeville, Ala., said of "Mockingbird": 'The book is not an indictment so much as a plea for something, a reminder to people at home.'"


title: Go Set a Watchman

text: The papers of Annie Laurie Williams and Maurice Crain, who were Harper Lee's literary agents in the 1950s, are held at Columbia University's Rare Book & Manuscript Library. They show that "Go Set a Watchman" was an early draft of "To Kill a Mockingbird", and underwent significant changes in story and characters during the revision process. Harper Lee was writing "Go Set a Watchman" in January 1957, and sold the manuscript to the publisher J. B. Lippincott in October 1957. She then continued to work on the manuscript for the next two years, submitting revised manuscripts to her literary agents. At some point in that two-year period, Lee renamed her book "To Kill a Mockingbird". Some of these records have been copied and posted online.


title: Go Set a Watchman

text: The manuscript was long thought to have been lost. According to "The New York Times", the typed manuscript of "Go Set a Watchman" was first found, during an appraisal of Lee's assets in 2011, in a safe deposit box in Lee's hometown of Monroeville. Lee's lawyer, Tonja Carter, later revealed that she had first assumed the manuscript to be an early draft of "To Kill a Mockingbird". Later, upon learning in the middle of 2014 of the existence of a second novel at a family gathering, she then re-examined Lee's safe-deposit box and found the manuscript for "Go Set a Watchman". After contacting Lee and reading the manuscript, she passed it on to Lee's agent, Andrew Nurnberg.


title: Go Set a Watchman

text: Some publications have called the timing of the book "suspicious", citing Lee's declining health, statements she had made over several decades that she would not write or release another novel, and the death of her sister and caregiver two months before the announcement. NPR reported on the news of her new book release, with circumstances "raising questions about whether she is being taken advantage of in her old age". Some publications have even called for fans to boycott the work. News sources, including NPR and BBC News, have reported that the conditions surrounding the release of the book are unclear and posit that Lee may not have had full control of the decision. Investigators for the state of Alabama interviewed Lee in response to a suspicion of elder abuse in relation to the publication of the book. However, by April 2015 the investigation had found that the claims were unfounded.


title: Go Set a Watchman

text: Historian and Lee's longtime friend Wayne Flynt told the "Associated Press" that the "narrative of senility, exploitation of this helpless little old lady is just hogwash. It's just complete bunk." Flynt said he found Lee capable of giving consent and believes no one will ever know for certain the terms of said consent.


title: Go Set a Watchman

text: Marja Mills, author of "The Mockingbird Next Door: Life with Harper Lee", a friend and former neighbor of Lee and her sister Alice, had a contrasting perception. In her piece for "The Washington Post" "The Harper Lee I knew" she quotes Lee's sister Alice, whom she describes as Lee’s "gatekeeper, advisor, protector" for most of Lee's adult life, as saying "Poor Nelle Harper can't see and can't hear and will sign anything put before her by anyone in whom she has confidence." She makes note that "Watchman" was announced just two and a half months after Alice's death and that all correspondence to and from Lee goes through her new attorney. She describes Lee as "in a wheelchair in an assisted living center, nearly deaf and blind, with a uniformed guard posted at the door" and her visitors "restricted to those on an approved list".


title: Go Set a Watchman

text: "New York Times" columnist Joe Nocera continues this argument. He also takes issue with how the book has been promoted by the “Murdoch Empire” as a "Newly discovered" novel, attesting that the other people in the Sotheby's meeting insist that Lee's attorney was present in 2011, when Lee's former agent (whom she subsequently fired) and the Sotheby's specialist found the manuscript. They say she knew full well that it was the same one submitted to Lippencott in the 1950s that was reworked into "Mockingbird", and that Carter had been sitting on the discovery, waiting for the moment when she, and not Alice, would be in charge of Harper Lee's affairs. He questions how commentators are treating the character of Atticus as though he were a real person and are deliberately trying to argue that the character evolved with age as opposed to evolved during development of the novel. He quotes Lee herself from one of her last interviews in 1964 where she said, "I think the thing that I most deplore about American writing—is a lack of craftsmanship. It comes right down to this—the lack of absolute love for language, the lack of sitting down and working a good idea into a gem of an idea." He states that, "a publisher that cared about Harper Lee's legacy would have taken those words to heart, and declined to publish "Go Set a Watchman"the good idea that Lee eventually transformed into a gem. That HarperCollins decided instead to manufacture a phony literary event isn't surprising. It's just sad."


title: Go Set a Watchman

text: Others have questioned the context of the book's release, not in matters of consent, but that it has been publicized as a sequel as opposed to an unedited first draft. There is no foreword to the book, and the dust jacket, although noting that the book was written in the mid-1950s, gives the impression that the book was written as a sequel or companion to "Mockingbird", which was never Lee's intention. Edward Burlingame, who was an executive editor at Lippincott when "Mockingbird" was released, has stated that there was never any intention, then or after, on the part of Lee or Hohoff, to publish "Watchman". It was simply regarded as a first draft. "Lippincott’s sales department would have published Harper Lee’s laundry list", Burlingame said. "But Tay really guarded Nelle like a junkyard dog. She was not going to allow any commercial pressures or anything else to put stress on her to publish anything that wouldn’t make Nelle proud or do justice to her. Anxious as we all were to get another book from Harper Lee, it was a decision we all supported." He said that in all his years at Lippincott, "there was never any discussion of publishing "Go Set a Watchman"".


title: Go Set a Watchman

text: "Go Set a Watchman" received mixed reviews. Michiko Kakutani in "The New York Times" described Atticus' characterization as "shocking", as he "has been affiliating with raving anti-integration, anti-black crazies, and the reader shares [Scout's] horror and confusion". Aside from this revelation, Kakutani notes that "Watchman" is the first draft of "Mockingbird" and discusses how students of writing will find "Watchman" fascinating for that reason. A reviewer for "The Wall Street Journal" described the key theme of the book as disillusionment. Despite Atticus' bigotry in the novel, he wins a case similar to the one he loses in "To Kill a Mockingbird". Michelle Dean of "The Guardian" wrote that many reviewers, such as Michiko Kakutani, allowed their personal convictions and takes of the controversy that erupted before the publication to leak into the reviews. She defends the novel as a "pretty honest confession of what it was to grow up a whip-smart, outspoken, thinking white woman in the south...[-] unpleasant", and stated that the book's bad reception is due to the "[shattering of] everyone's illusions...that Harper Lee was living in satisfied seclusion".


title: Go Set a Watchman

text: "Entertainment Weekly" panned the book as "a first draft of "To Kill a Mockingbird"" and said, "Though "Watchman" has a few stunning passages, it reads, for the most part, like a sluggishly paced first draft, replete with incongruities, bad dialogue, and underdeveloped characters". "Ponderous and lurching", wrote William Giraldi in "The New Republic", "haltingly confected, the novel plods along in search of a plot, tranquilizes you with vast fallow patches, with deadening dead zones, with onslaughts of cliché and dialogue made of pamphleteering monologue or else eye-rolling chitchat". On the other hand, Dara Lind of Vox states that "it's ironic that the reception of "Go Set a Watchman" has been dominated by shock and dismay over the discovery that Atticus Finch is a racist, because the book is literally about Scout — who now goes by her given name, Jean Louise — ...[who] has been living in New York, and quietly assumed that her family back home is just as anti-segregationist as she is". In "The New Yorker", Adam Gopnik commented that the novel could be seen as "a string of clichés", although he went on to remark that "some of them are clichés only because, in the half century since Lee's generation introduced them, they've "become" clichés; taken on their own terms, they remain quite touching and beautiful". Maureen Corrigan in NPR Books called the novel "kind of a mess". In "The Spectator", Philip Hensher called "Go Set a Watchman" "an interesting document and a pretty bad novel", as well as a "piece of confused juvenilia". ""Go Set A Watchman" is not a horrible book, but it's not a very good one, either", judged the "Fort Worth Star-Telegram", citing among other flaws its "overly simplistic" plot.


title: Go Set a Watchman

text: Alexandra Petri wrote in "The Washington Post", "It is an inchoate jumble ... "Go Set a Watchman" is not, by any stretch of the imagination, a good, or even a finished book. For the first 100 pages it lacks anything that could even charitably be described as a plot. ... [T]he writing is laughably bad. ... I flung the book down and groaned audibly and I almost did not pick it back up even though I knew I had fewer than 100 pages to go. ... This should not have been published. It’s 280 pages in desperate need of an editor. ... If you were anywhere in the vicinity of me when I was reading the thing, you heard a horrible bellowing noise, followed by the sound of a book being angrily tossed down. ..." Contrastingly, Sam Sacks of "The Wall Street Journal" praised the book for containing "the familiar pleasures of Ms. Lee’s writing—the easy, drawling rhythms, the flashes of insouciant humor [and] the love of anecdote".


title: Go Set a Watchman

text: Author Ursula K. Le Guin wrote that "Harper Lee was a good writer. She wrote a lovable, greatly beloved book. But this earlier one, for all its faults and omissions, asks some of the hard questions "To Kill a Mockingbird" evades."


title: Go Set a Watchman

text: "Go Set a Watchman" set a record for the highest adult novel one-day sales at Barnes & Noble, which included digital sales and pre-orders made before July 14. Barnes & Noble declined to release the exact number.


title: Go Set a Watchman

text: Some translations of the novel have appeared. In the Finnish translation of the novel by Kristiina Drews, "nigger" is translated as if "negro" or "black" had been used. Drews stated that she interpreted what was meant each time, and used vocabulary not offensive to black people.


title: Lamarckism

text: Lamarckism, also known as Lamarckian inheritance or neo-Lamarckism, is the notion that an organism can pass on to its offspring physical characteristics that the parent organism acquired through use or disuse during its lifetime. It is also called the inheritance of acquired characteristics or more recently soft inheritance. The idea is named after the French zoologist Jean-Baptiste Lamarck (1744–1829), who incorporated the classical era theory of soft inheritance into his theory of evolution as a supplement to his concept of orthogenesis, a drive towards complexity.


title: Lamarckism

text: Introductory textbooks contrast Lamarckism with Charles Darwin's theory of evolution by natural selection. However, Darwin's book "On the Origin of Species" gave credence to the idea of heritable effects of use and disuse, as Lamarck had done, and his own concept of pangenesis similarly implied soft inheritance.


title: Lamarckism

text: Many researchers from the 1860s onwards attempted to find evidence for Lamarckian inheritance, but these have all been explained away, either by other mechanisms such as genetic contamination or as fraud. August Weismann's experiment, considered definitive in its time, is now considered to have failed to disprove Lamarckism, as it did not address use and disuse. Later, Mendelian genetics supplanted the notion of inheritance of acquired traits, eventually leading to the development of the modern synthesis, and the general abandonment of Lamarckism in biology. Despite this, interest in Lamarckism has continued.


title: Lamarckism

text: Studies in the fields of epigenetics, genetics, and somatic hypermutation have highlighted limited inheritance of traits acquired by the previous generation. The characterization of these findings as Lamarckism has been disputed. The inheritance of the hologenome, consisting of the genomes of all an organism's symbiotic microbes as well as its own genome, is also somewhat Lamarckian in effect, though entirely Darwinian in its mechanisms.


title: Lamarckism

text: The inheritance of acquired characteristics was proposed in ancient times, and remained a current idea for many centuries. The historian of science Conway Zirkle wrote in 1935 that:


title: Lamarckism

text: Zirkle noted that Hippocrates described pangenesis, the theory that what is inherited derives from the whole body of the parent, whereas Aristotle thought it impossible; but that all the same, Aristotle implicitly agreed to the inheritance of acquired characteristics, giving the example of the inheritance of a scar, or of blindness, though noting that children do not always resemble their parents. Zirkle recorded that Pliny the Elder thought much the same. Zirkle pointed out that stories involving the idea of inheritance of acquired characteristics appear numerous times in ancient mythology and the Bible, and persisted through to Rudyard Kipling's "Just So Stories". The idea is mentioned in 18th century sources such as Diderots "D'Alembert's Dream". Erasmus Darwin's "Zoonomia" (c. 1795) suggested that warm-blooded animals develop from "one living filament... with the power of acquiring new parts" in response to stimuli, with each round of "improvements" being inherited by successive generations.


title: Lamarckism

text: Charles Darwin's "On the Origin of Species" proposed natural selection as the main mechanism for development of species, but (like Lamarck) gave credence to the idea of heritable effects of use and disuse as a supplementary mechanism. Darwin subsequently set out his concept of pangenesis in the final chapter of his book "The Variation of Animals and Plants Under Domestication" (1868), which gave numerous examples to demonstrate what he thought was the inheritance of acquired characteristics. Pangenesis, which he emphasised was a hypothesis, was based on the idea that somatic cells would, in response to environmental stimulation (use and disuse), throw off 'gemmules' or 'pangenes' which travelled around the body, though not necessarily in the bloodstream. These pangenes were microscopic particles that supposedly contained information about the characteristics of their parent cell, and Darwin believed that they eventually accumulated in the germ cells where they could pass on to the next generation the newly acquired characteristics of the parents.


title: Lamarckism

text: Darwin's half-cousin, Francis Galton, carried out experiments on rabbits, with Darwin's cooperation, in which he transfused the blood of one variety of rabbit into another variety in the expectation that its offspring would show some characteristics of the first. They did not, and Galton declared that he had disproved Darwin's hypothesis of pangenesis, but Darwin objected, in a letter to the scientific journal "Nature", that he had done nothing of the sort, since he had never mentioned blood in his writings. He pointed out that he regarded pangenesis as occurring in protozoa and plants, which have no blood, as well as in animals.


title: Lamarckism

text: Between 1800 and 1830, Lamarck proposed a systematic theoretical framework for understanding evolution. He saw evolution as comprising four laws:


title: Lamarckism

text: In 1830, in an aside from his evolutionary framework, Lamarck briefly mentioned two traditional ideas in his discussion of heredity, in his day considered to be generally true. The first was the idea of use versus disuse; he theorized that individuals lose characteristics they do not require, or use, and develop characteristics that are useful. The second was to argue that the acquired traits were heritable. He gave as an imagined illustration the idea that when giraffes stretch their necks to reach leaves high in trees, they would strengthen and gradually lengthen their necks. These giraffes would then have offspring with slightly longer necks. In the same way, he argued, a blacksmith, through his work, strengthens the muscles in his arms, and thus his sons would have similar muscular development when they mature. Lamarck stated the following two laws:


title: Lamarckism

text: In essence, a change in the environment brings about change in "needs" ("besoins"), resulting in change in behaviour, causing change in organ usage and development, bringing change in form over time—and thus the gradual transmutation of the species. The evolutionary biologists and historians of science Conway Zirkle, Michael Ghiselin, and Stephen Jay Gould have pointed out, these ideas were not original to Lamarck.


title: Lamarckism

text: August Weismann's germ plasm theory held that germline cells in the gonads contain information that passes from one generation to the next, unaffected by experience, and independent of the somatic (body) cells. This implied what came to be known as the Weismann barrier, as it would make Lamarckian inheritance from changes to the body difficult or impossible.


title: Lamarckism

text: Weismann conducted the experiment of removing the tails of 68 white mice, and those of their offspring over five generations, and reporting that no mice were born in consequence without a tail or even with a shorter tail. In 1889, he stated that "901 young were produced by five generations of artificially mutilated parents, and yet there was not a single example of a rudimentary tail or of any other abnormality in this organ." The experiment, and the theory behind it, were thought at the time to be a refutation of Lamarckism.


title: Lamarckism

text: The experiment's effectiveness in refuting Lamarck's hypothesis is doubtful, as it did not address the "use and disuse" of characteristics in response to the environment. The biologist Peter Gauthier noted in 1990 that:


title: Lamarckism

text: Ghiselin also considered the Weismann tail-chopping experiment to have no bearing on the Lamarckian hypothesis, writing in 1994 that:


title: Lamarckism

text: The acquired characteristics that figured in Lamarck's thinking were changes that resulted from an individual's own drives and actions, not from the actions of external agents. Lamarck was not concerned with wounds, injuries or mutilations, and nothing that Lamarck had set forth was tested or "disproven" by the Weismann tail-chopping experiment.


title: Lamarckism

text: The historian of science Rasmus Winther stated that Weismann had nuanced views about the role of the environment on the germ plasm. Indeed, like Darwin, he consistently insisted that a variable environment was necessary to cause variation in the hereditary material.