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Probably approximately correct learning

In computational learning theory, probably approximately correct (PAC) learning is a framework for mathematical analysis of machine learning. It was proposed in 1984 by Leslie Valiant.

In this framework, the learner receives samples and must select a generalization function (called the hypothesis) from a certain class of possible functions. The goal is that, with high probability (the "probably" part), the selected function will have low generalization error (the "approximately correct" part). The learner must be able to learn the concept given any arbitrary approximation ratio, probability of success, or distribution of the samples.

The model was later extended to treat noise (misclassified samples).

An important innovation of the PAC framework is the introduction of computational complexity theory concepts to machine learning. In particular, the learner is expected to find efficient functions (time and space requirements bounded to a polynomial of the example size), and the learner itself must implement an efficient procedure (requiring an example count bounded to a polynomial of the concept size, modified by the approximation and likelihood bounds).

Definitions and terminology
In order to give the definition for something that is PAC-learnable, we first have to introduce some terminology.

For the following definitions, two examples will be used. The first is the problem of character recognition given an array of $$n$$ bits encoding a binary-valued image. The other example is the problem of finding an interval that will correctly classify points within the interval as positive and the points outside of the range as negative.

Let $$X$$ be a set called the instance space or the encoding of all the samples. In the character recognition problem, the instance space is $$X=\{0,1\}^n$$. In the interval problem the instance space, $$X$$, is the set of all bounded intervals in $$\mathbb{R}$$, where $$\mathbb{R}$$ denotes the set of all real numbers.

A concept is a subset $$c \subset X$$. One concept is the set of all patterns of bits in $$X=\{0,1\}^n$$ that encode a picture of the letter "P". An example concept from the second example is the set of open intervals, $$\{ (a,b) \mid 0 \leq a \leq \pi/2, \pi \leq b \leq \sqrt{13} \}$$, each of which contains only the positive points. A concept class $$C$$ is a collection of concepts over $$X$$. This could be the set of all subsets of the array of bits that are skeletonized 4-connected (width of the font is 1).

Let $$EX(c,D)$$ be a procedure that draws an example, $$x$$, using a probability distribution $$D$$ and gives the correct label $$c(x)$$, that is 1 if $$x \in c$$ and 0 otherwise.

Now, given $$0<\epsilon,\delta<1 $$, assume there is an algorithm $$A$$ and a polynomial $$p$$ in $$1/\epsilon, 1/\delta$$ (and other relevant parameters of the class $$C$$) such that, given a sample of size $$p$$ drawn according to $$EX(c,D)$$, then, with probability of at least $$1-\delta$$, $$A$$ outputs a hypothesis $$h \in C$$ that has an average error less than or equal to $$\epsilon$$ on $$X$$ with the same distribution $$D$$. Further if the above statement for algorithm $$ A $$ is true for every concept $$c \in C$$ and for every distribution $$D$$ over $$X$$, and for all $$0<\epsilon, \delta<1$$ then $$C$$ is (efficiently) PAC learnable (or distribution-free PAC learnable). We can also say that $$A$$ is a PAC learning algorithm for $$C$$.

Equivalence
Under some regularity conditions these conditions are equivalent:

 * 1) The concept class C is PAC learnable.
 * 2) The VC dimension of C is finite.
 * 3) C is a uniformly Glivenko-Cantelli class.
 * 4) C is compressible in the sense of Littlestone and Warmuth

title: Probably approximately correct learning


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Order of the Estonian Red Cross

The Order of the Estonian Red Cross (Eesti Punase Risti teenetemärk; Ordre de la Croix-Rouge Estonienne) was instituted in 1920 by the Estonian Red Cross Society. The Order of the Estonian Red Cross is bestowed in order to give recognition for humanitarian services rendered in the interests of the Estonian people and for the saving of life.

Classes
The Order of the Estonian Red Cross comprises six classes:
 * Five basic classes – 1st, 2nd, 3rd, 4th and 5th class;
 * One medal class.

The crosses of all basic classes of the Order of the Estonian Red Cross have the same design.

The blue colour tone of the moiré ribands belonging to the decorations of all the classes of the Order of the Estonian Red Cross is determined according to the international PANTONE colour-table as 297 MC.

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/

title: Order of the Estonian Red Cross


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The Time Ships

The Time Ships is a 1995 hard science fiction novel by Stephen Baxter. A canonical sequel to the 1895 novella The Time Machine by H. G. Wells, it was officially authorized by the Wells estate to mark the centenary of the original's publication. The Time Ships won critical acclaim. It won the John W. Campbell Memorial Award and the Philip K. Dick Award in 1996, as well as the British Science Fiction Association Award in 1995. It was also nominated for the Hugo, Clarke and Locus Awards in 1996.

Plot summary
After the events related in The Time Machine, the Time Traveler (his first name, Moses, is given in the novel but applied to the Time Traveler's younger self) prepares, in 1891, to return to the year 802,701 and save Weena, the Eloi who died in the fire with the Morlocks. He reveals that the quartz construction of the time machine is suffused with a radioactive substance he calls Plattnerite for the mysterious benefactor who gave him the sample to study twenty years earlier, in 1871.

The Time Traveler departs into the future and stops in AD 657,208 when he notes the daytime sky has gone permanently dark. He arrives and is abducted by a branch of Morlocks more culturally advanced than the ones he met before. One of their number, Nebogipfel (the name of a character from Wells' The Chronic Argonauts), explains after hearing the Time Traveler's own story that the conflict between Eloi and Morlocks never occurred due to the Writer's publication of the story that became The Time Machine. The timeline he sought to go to is inaccessible to him now. The Morlocks of this timeline have constructed a Dyson sphere around the inner Solar System and use the Sun's energy to power it. Humans as the Time Traveler knows them live on the sunlit inner surface of the Sphere while the Morlocks live on the outer shell. The Time Traveler convinces Nebogipfel that he will help him understand the time travelling mechanism of the time machine if the Morlock takes him back to it.

When he thinks he is unobserved, the Time Traveler reactivates his machine and travels to 1873 to persuade his younger self to stop his research on Plattnerite. Nebogipfel, who took hold of the Time Traveler once he realized what he was doing, follows him there. As the Time Traveler attempts to persuade his younger self, whom he calls "Moses" to avoid confusion, to stop his research by providing Nebogipfel as proof that reality is changed by time travel, a tank-like Juggernaut pulls into Moses' yard. The army personnel on board, commanded by Hilary Bond and accompanied by an older version of the Time Traveler's friend Filby, take Moses, Nebogipfel, and the Time Traveler to their 1938, where World War I has stretched over twenty-four years due to the discovery of time travel which was influenced by the latter's work. Britain's major cities are all encased in Domes, and with the contributions of Austrian expatriate Kurt Gödel, the government hopes to win the war by altering Germany's history conclusively.

Nebogipfel explains to the Time Traveler that they've entered another future as a result of their actions in Moses' past. During another bombing raid on London by the Germans, Gödel provides a vial of Plattnerite and leads them to the only escape available, a Time-Car prototype. Upon hearing this and what society would be like after the war (a pessimistic view mirroring Wells' own), the Time Traveler and Nebogipfel mount the vehicle and insert the Plattnerite. Moses is killed in an explosion when he tries to save Gödel, and the Time-Car travels back to the Paleocene and is wrecked on a tree. After weeks of bare survival, the Time Traveler and Nebogipfel are discovered by a scouting party from the Chronic Expeditionary Force commanded by Hilary Bond that arrived from 1944 to find them based on their remains in her time. Some time later, a German Messerschmitt plane arrives over the campsite, drops a Carolinum bomb (analogous to an atomic bomb in our world; see Wells' The World Set Free), and devastates the time-traveling Juggernauts and all but twelve of the Force. Nebogipfel and the Time Traveler survive by hiding in the ocean.

Over the next year and a half, the stranded soldiers under Hilary Bond's command start the colony of First London. In off moments, Nebogipfel has worked on repairing the Time-Car and acquired shavings of Plattnerite to power it on a journey through time. When the Time-Car is ready, the Time Traveler joins Nebogipfel in a fifty-million year journey through which they see First London expand and develop colonies on the moon and in Earth orbit. Eventually, human tampering with the Earth's environment renders the planet uninhabitable, and humanity departs for the stars. When the Time-Car finally stops due to depletion of its Plattnerite fuel, Nebogipfel and the Time Traveler are tended by a Universal Constructor, a life form (or lifeforms) composed of thousands of nanotechnological entities. They see that there are few stars left in the night sky; this is due to the human descendants colonizing many worlds and constructing Dyson Spheres around the host stars. The goal of the Universal Constructor is to harvest the energy of the sun to build time-travel vehicles from Plattnerite and travel to the beginning of the universe. However, this goal is not due to be completed for a million years.

Nebogipfel and the Time Traveler acquire enough Plattnerite from the Constructors to journey to the point in the future (i.e. another million years hence) when the Constructors will have finished building their time ships. Once the Time Traveler and Nebogipfel reach this point, the Constructors integrate them into a time ship and thus begins the journey back to time's beginning. At this central point from where all matter and energy and timelines branch off, the Constructors apparently start a new history in which they become something even more grand and knowledgeable than before. These successors of the Constructors place the Time Traveler and Nebogipfel into the Time Traveler's original history in the year 1871. It is revealed that the Time Traveler himself is the mysterious stranger who gave his younger self the Plattnerite sample under the alias "Gottfried Plattner", and that because of this, the circle of causality is closed and thus, the whole multiplicity of histories which ends up creating the Constructors and their successors begins anew. Nebogipfel, with his consciousness enhanced by his time with the Constructors, leaves the Time Traveler behind to travel with the successors of the Constructors. These successors plan to travel "beyond" the "local" multiplicity into a new realm of historical dimensions.

The Time Traveler then makes one final journey to AD 802,701, along his historical axis, and just barely saves Weena from the death she suffered before. Since (the reader is led to suppose) travelling in time again would cause this reality to branch off and become inaccessible again, the Time Traveler destroys the machine and encourages the Eloi in an Agrarian Revolution to reduce their dependence on the Morlocks for food and clothing, hoping to one day eliminate it entirely. As he works, the Time Traveler writes down the recounting of his adventures and seals them in a Plattnerite packet, a "time capsule", so to speak, in the hope that it will travel in time to a faithful scribe. Before sealing the packet, the Time Traveler writes that he plans to go into the world of the Morlocks again, hopefully to return and add an appendix to the story. The book ends by saying that no appendix was found.

References to the works of H. G. Wells

 * The name Gottfried Plattner comes from The Plattner Story (included in Wells' collection of short stories entitled The Country of the Blind and Other Stories, written between 1894 and 1909, first published in 1911). There is no original link between this story and The Time Machine, nor does the account related to us by Baxter at the end of The Time Ships echo an event from The Plattner Story. In Wells' original story, Gottfried Plattner is given a full backstory including ancestry and occupation. He is a school teacher made to chemically analyze a "green powder" of uncertain origin by his students, and, upon lighting the powder on fire, is violently launched into a mysterious parallel dimension next to ours where mute "Watchers of the Living", obviously deceased souls or alternate versions of existing people in our world, take keen interest in us.
 * The Morlock Nebogipfel takes his name from Wells' story "The Chronic Argonauts".
 * In the London Dome, the characters are introduced to the Babble Machines, an entertainment/propaganda device, which originally appeared in Wells' When the Sleeper Wakes.
 * Wells himself (as "the Writer") is described as giving a lecture on a Babble Machine, and it is mentioned that he may have "a great deal of influence on official thinking on The Shape of Things to Come".
 * The dome is somewhat similar in concept to the post world war "Bombproofs" mentioned as existing in London after the second world war in The Shape of Things to Come though this is on a much vaster scale. A similar design is reused by Baxter and Arthur C Clarke in their novel Sunstorm, for the vast dome used to shield London from the Storm of the novel's title.
 * When the London Dome is breached, the sound of the alarms is described as "ulla, ulla, ulla", which is the cry of the Martian Tripods in The War of the Worlds.
 * In the Paleocene Age, the Time Traveler succumbs to a bacterial infection as his body is ill-adapted to the environment, much like the Martians in The War of the Worlds.
 * The people of the Green Moon are referred to as Selenites, as are the inhabitants of the moon in The First Men in the Moon.
 * The novel suggests that the universe of the Time Traveler is not ours, but a slightly different one, coherent with Wells novels (whereas Nebogipfel's original timeline created by the publication of the time traveler's first travel in The Time-Machine, according to what he relates of it to the time traveler, appears to be much more similar to ours). Nuclear energy is produced by a material called carolinum and not uranium. Carolinum allows plattnerite to be produced relatively easily. Carolinum bombs, contrary to A-bombs, continue to detonate for years with an eerie purple glow. The name carolinum and the continuous detonation are references to The World Set Free.
 * In the Palace of Green Porcelain, the Time Traveler views a model of a city resembling London as it is described in When the Sleeper Wakes.
 * As the Time Traveler 're-enters' his body following the journey to the Origin of the Universe, much of the description recalls the ending of Under the Knife.

Awards

 * British Science Fiction Award winner, 1995
 * John W. Campbell Memorial Award winner, 1996
 * Philip K. Dick Award winner, 1997
 * British Fantasy Award nominee, 1996
 * Arthur C. Clarke Award nominee, 1996
 * Hugo Award nominee, 1996
 * Locus Award nominee, 1996
 * Kurd-Laßwitz-Preis winner, 1996
 * Premio Gigamesh winner, 1997
 * Seiun Award winner, 1999

title: The Time Ships


text:
Evolution (Baxter novel)

Evolution is a collection of short stories that work together to form an episodic science fiction novel by author Stephen Baxter. It follows 565 million years of human evolution, from shrewlike mammals 65 million years in the past to the ultimate fate of humanity and its descendants, both biological and non-biological, 500 million years in the future.

Protagonists in the Purga–human line
Characters listed below descend from Purga and are either ancestral to or descended from humans.

Purga (65 Mya, Montana). A female Purgatorius. Despite being a shrew-like insectivore and barely self-aware, she is ancestral to all primates. After losing two mates and their litters to a Troodon attack and cannibalism, she manages to bear two pups. They witness the Chicxulub impact, although one of the pups is cooked alive and her mate succumbs to hypothermia. Purga and her surviving pup eventually arrive at a shore, where other Purgatorius are feeding on a dying Ankylosaurus. Her pup joins them but Purga, now elderly and satisfied that her offspring will survive, retreats and dies in her burrow. She is fossilized and her tooth is discovered by Joan Useb in 2010.

Plesi (63 Mya, North America). A female plesiadapid. Although Earth is lush again, her species still looks very similar to Purgatorius. She has two pups and one of them is killed by an Oxyclaenus.

Noth (51 Mya, Ellesmere Island). A 2-year-old Notharctus male living with its herd in the Arctic forests. His species is lemur-looking, matriarchal and far more social, but still lacks a theory of mind. Noth wanders for weeks with his sister, surviving an attack on their family by a sociopathic fellow, Solo. They eventually find another herd, whose leader accepts Noth and his sister for defeating Solo and allows them to mate with the rest of the herd.

Capo (5 Mya, North African coast). A 40-year-old australopithecine dominant male living in the dry Mediterranean basin. His species has occasional consciousness, basic bipedalism, instinctive toolmaking and a theory of mind, but is incapable of teaching. As his forest is shrinking, Capo leads part of his group to a larger one, despite being ill-suited to cross the plains in between. However, it is already claimed by a bigger clan of their species and they are forced to live in the open plains and feed off carcasses.

Far (1.5 Mya, Rift Valley). A 9-year-old female hominid living with her tribe in the savannah. Her species is now fully bipedal and omnivorous, as well as surviving past their reproductive age to take important social roles. Forced by a grassland fire to take refuge in a jungle, she survives an attack by pithecines and eventually joins another hominid tribe, who use axes much to her amazement. She invents body painting while playing with ocher, allowing her to court Ax, a young male, and be accepted by the rest of the group.

Pebble (127 kya, Central Kenya). An 8-year-old neanderthal male. After his tribe is attacked, he leads the survivors and settle in the Mediterranean coast years later. There he meets Harpoon, a female modern human (Homo sapiens sapiens). Her tribe has more sophisticated huts and tools, as well as clothing and domesticated wolves. Trading seafood for tools, both tribes come together and Pebble and Harpoon mate. After swimming afloat logs to a nearby island, they exterminate the last Homo erectus there.

Mother or Ja-ahn (60 kya, Sahara). A 30-year-old woman living in the savannah. Schizophrenia allows her to understand causality, invent the spear-thrower and form simple sentences, which are quickly learned by the rest of her tribe. When her son dies, Mother murders her aunt believing that she was responsible through unseen means. The incident gives rise to superstition and Mother is regarded as a sage. Two more members are sacrificed due to Mother's superstitions about blood and rain in an attempt to solve the drought. She eventually dies of cancer and is named Ja-ahn after their language's word for "mother", becoming the first human with a proper name, as well becoming mythicized.

Ejan (52 kya, Indonesia). A 20-year-old man. His people are the most ancient characters in the novel that speak normally. He lives with his ill mother and their increasingly crowded village. Ejan carves a canoe with his sister Rocha to sail to the southern landmass, becoming the first humans to set foot in Australia. Over the next millennium, people migrate there and the siblings become mythicized.

Jana (51 kya, Northwestern Australia). A 21-year-old man. He tries to court a girl but is not allowed to by her brothers due to his polio-struck leg. To hunt large game, he invents setting forests on fire and manages to trap a Genyornis. He returns with its head, impressing the village.

Jo'on (47 kya, New South Wales). A 40-year-old man partnered with Leda, a 39-year-old woman. As Leda's brother uses flint to hunt better than with spears, she asks Jo'on to go the coast to obtain some.

Jahna (31 kya, Western France). A girl living in a settlement during the Ice Age. Her people's village, cognitive capacity and culture are far more sophisticated than those of neanderthals, which they often abuse and exploit. While hunting, Jahna and her brother get lost when an ice storm breaks. Days later, they end up in the cave of a massive, 40-year-old neanderthal male, "Old Man". Though superficially dangerous and unable to speak, Old Man takes care of them. However, a team led by their father eventually finds them and bludgeons Old Man in his sleep, amidst the children's protests.

Juna (9.6 kya, Anatolia). A pregnant 15-year-old girl living in a village of hunter-gatherers undergoing famine. She accepts to become the slave of Cahl, the beer trader, to save her unborn child from being killed at birth. At Cahl's hometown, Juna learns about agriculture and is put to work in the fields. Although food is plenty, monoculture means that the villagers' diet and health are poorer than those of hunter-gatherers. When tribute-collector Keram arrives, Juna learns about the city of Cata Huuk, and convinces him that she was kidnapped from there long ago. In part due to her much better appearance, Keram takes her with him, despite Cahl's protests. Cata Huuk is Earth's first city, and its leader, the Potus, the first king. Juna is made to dance naked for the Potus, and eventually partners up with Keram. He gives birth to her child and then Keram's. After four years of plenitude, famine-caused revolts force the family to flee Cata Huuk. Along the way, Keram brings Juna to the ruins of her original and now measles-struck village, where she finds her sister as the sole survivor.

Athalaric (482 CE, Rome). The son of a barbarian slave, under the tutelage and in charge of the protection of Honorius, a venerable Roman bone collector. Visiting a Rome that is just a shadow of its former glory, the Persian trader Papak convinces them to join a Scythian collector in Petra. There, Honorius becomes so excited after acquiring a Homo erectus skull that he invites the entire group to a museum in Rome, where they misidentify a Protoceratops as a griffin. Honorius is confident that the remains prove that living beings were radically different in the past. Away on a cave expedition, Athalaric asks Honorius to become a priest on his father's request, to lead Rome away from decay. Honorius however is not interested and is murdered by the henchmen of Athalaric's father. His remains are buried next to Old Man's.

Joan Useb (21st century). A paleontologist of San and European ancestry. In 2031, she is pregnant and flying to a conference in Rabaul on global warming, where she meets primatologist Alyce Sigurdardottir and Bex Scott, the genetically enhanced daughter of celebrity scientist Alison Scott. As protesters from the "Fourth World" disrupt the conference, the Rabaul caldera erupts, setting the sequence of events that collapse civilization. In the epilogue, set in 2049, a 52-year-old Joan and her 18-year-old daughter Lucy rescue feral children left behind in the Galápagos Islands due to the ensuing wars and toxic rain. Reflecting on humanity's bleak future, Lucy asks Joan whether she has been happy and she responds affirmatively, based on the fact that unlike their ancestors, they have a glimpse into the past and can be certain that some form of life will survive into the far future.

Robert Wayne "Snowy" Snow (millennia from now, United Kingdom). A 31-year-old male military officer, genetically modified to facilitate cryogenic sleep. During the post-Rabaul wars, the United Nations deploys military officers in suspended animation worldwide to deter international invasions. Centuries later, officers Snowy, Ahmed, Sidewise, Bonner and Moon wake up and soon realize that human civilization has long collapsed. Ahmed, the leader, attempts to rebuild civilization, but with Moon being the only female, crops being long extinct and not knowing how to recreate even the most basic technology, Sidewise and Bonner agree that Ahmed's plan is completely unrealistic. A month later, Snowy discovers that there actually are humans, now feral and without language. Internal conflicts distance Sidewise and Bonner, Moon disappears, Ahmed succumbs to mercury poisoning from fish, and Snowy chooses to spend the rest of his life following the feral people. As Snowy arrives to the coast of Sussex, he reflects on how everything humans ever made is gone now.

Remembrance (30 My from now, Western Africa). A monkey-like post-human female. The descendants of feral children have diversified into many non-sapient species, from everything resembling arboreal primates (Remembrance's kind), eusocial moles, and elephants, the latter being "farmed" by rodents. They inhabit a lush forest, still having some artificial remains like bits of glass, bitumen and copper. Avoiding rodent and avian predators, Remembrance falls into a mole-folk pit, where she survives for several days. She eventually returns to the canopy, but soon the impact of Eros unleashes a mass extinction.

Ultimate (500 My from now, Montana). A capuchin-like post-human female inhabiting the barren deserts of Pangaea Ultima. Her species is closely symbiotic with borametz trees, which grow pods to sleep and nurse their young. Due to the harsh climate, the tree begins consuming Ultimate's child, and she takes her to the desert, accompanied with her friend, Cactus. They come across the descendants of beetles, rats, lizards and toads, and Cactus is hunted by a huge, transparent salamander. A few days later, Ultimate arrives to the shores of a drying inland sea, where she finds the hardened footprints of one of her kind, both of them being the last "human" explorers. After returning and giving her child to the tree, Ultimate becomes the last primate to reproduce, and soon her herd and tree die. In the following eons Earth is consumed by the Sun, but hibernating bacteria are hurled into space and end up on the seas of a habitable exoplanet, setting up evolution again.

Protagonists outside the Purga–human line
Characters listed below are not ancestral to or descend from humans, although some are primates and thus descend from Purga.

Listener (145 Mya, Pangaea). A female Ornitholestes living with Stego, her mate. Unlike most animals in the book, they are fully sapient, with complex language, leather belts, whips, and a culture that revolves around Diplodocus hunting. Stego is killed by an Allosaurus during a hunt, and Listener swears to kill the Diplodocus matriarch that indirectly caused his death. Ten years later, she and her three sons manage to hunt the matriarch, which dooms the herd as well as the Ornitholestes settlement. They become extinct and humans never discover that another sapient species preceded them.

Roamer (32 Mya, North Africa). A female of a capuchin-like primate species unknown to paleontology. After a flood destroys her home, she finds herself and other members of her species on a haphazard raft on the Atlantic. Starvation and thirst nearly kill them, but Roamer and two other survivors eventually land on the rainforests of Yucatán and their descendants give rise to a new line of monkeys.

Dig (10 Mya, Antarctica). A female of a lemming-like primate species. The Antarctica she inhabits still has forests inhabited by the descendants of Velociraptor, Allosaurus and Muttaburrasaurus. Though more temperate than today, the Antarctic forests are becoming progressively colder and more inhospitable. Ice caps completely bury the remains of Dig's ecosystem and humans never discover that non-avian dinosaurs survived 55 million years longer than previously thought.

Johnnie (21st century, Mars). Humanity's first self-replicating robot, which lands on Mars during Joan's conference. Although its original purpose is to construct bases for human habitation, it stops receiving orders due to the chaos unleashed by Rabaul's eruption on Earth and continues replicating itself unchecked. Within a few centuries, Johnnie's descendants have consumed the planet entirely and leave the Solar System. As the self-replication process is imperfect, they begin undergoing a process akin to biological evolution. About 500 million years later, a self-aware probe arrives on Earth to investigate the origins of its kind. Although it encounters evidence of past intelligent activity, and even Ultimate —its creators' descendant— it considers its mission a failure and leaves.

Reception
Peter Cannon reviewing for Publishers Weekly stated "here is a rigorously constructed hard SF novel where the question is not whether humanity will reach the stars but how it will survive its own worst tendencies." Kirkus Reviews called this novel "glum, dyspeptic, and depressing." Jackie Cassada said in her review for Library Journal that "spanning more than 165 million years and encompassing the entire planet, Baxter's ambitious saga provides both an exercise in painless paleontology and superb storytelling."

Evolution has been compared to Olaf Stapledon's Last and First Men. Baxter has acknowledged Stapledon's influence.

title: Evolution (Baxter novel)


text:
Order of the Cross of the Eagle

The Order of the Cross of the Eagle (Kotkaristi teenetemärk; Ordre de la Croix de l'Aigle) was instituted in 1928 by the Estonian Defence League to commemorate the tenth anniversary of Estonian independence. It was adopted as a state order in 1936. The Order of the Cross of the Eagle is bestowed to give recognition for military services and services in the field of national defence. It is awarded in civil and military divisions. The awards made to members of the military are denoted by the addition of crossed swords to the decoration.

Classes
The Order of the Cross of the Eagle comprises eight classes:
 * Five basic classes - 1st, 2nd, 3rd, 4th and 5th class;
 * Three medal classes - crosses in gold, silver and iron;

The crosses of all the classes of the Order of the Cross of the Eagle have the same design.

The colour tone of the orange moiré ribands belonging to the decorations of all the classes of the Order of the Cross of the Eagle is determined according to the international PANTONE colour-table as 137 MC.

The Order of the Cross of the Eagle is a military decoration if two crossed swords are affixed to it as follows: The medals of the affiliated crosses of the Order of the Cross of the Eagle have swords in the same metal as their cross.
 * The cross has crossed swords movably attached at the hilts of the swords to the tips of the top arms of the cross. The length of the swords together with their hilts is 35 mm for the 1st, 2nd and 3rd class decorations and 33 mm for the 4th and 5th class decorations and the gold, silver and iron crosses;
 * The star has crossed swords affixed to the oblique rays of the star and the vertical and horizontal rays remain uncovered. The swords are set hilts down. The length of each sword is 85 mm.

title: Order of the Cross of the Eagle


text:
Talk:Silicon controlled rectifier

Inventor: Gordon and Robert Hall are not the same person
I'm reverting part of the edit made 14:16, 11 July 2012 by 63.87.61.59. That IP user seems to be a well-meaning vandal per the users' talk page, and for some reason changed Gordon Hall's name to Robert Hall, probably because Robert was an EE working on rectifiers at GE at the time, and already had a Wikipedia page that could be linked to. Gordon Hall is my uncle. I do need to dig up the patent number and cite it here. There is some language at https://sites.google.com/site/transistorhistory/Home/us-semiconductor-manufacturers/general-electric-history which mentions Gordon and the SCR development in particular, but most of that page is about Robert, which just adds to the confusion. Bill Gutzwiller's oral history at http://www.semiconductormuseum.com/Transistors/GE/OralHistories/Gutzwiller/Gutzwiller_Page6.htm describes Gordon's involvement in more detail. For now I'll cite the latter in the main article. Stevegt (talk) 15:59, 13 April 2014 (UTC)

Modes of Operation
I removed this partial sentence from the end of the Modes of Operation section, not sure what was trying to be said here: " A unijunction transistor is commonly used to trigger ". Wegsjac (talk) 15:21, 2 October 2012 (UTC)

The details about "Forward Blocking" aren't clear. It currently says "In this mode of operation, the anode is given a positive voltage while the cathode is given a negative voltage, keeping the gate at zero potential i.e. disconnected.". My question about this is - if the gate is at zero volt, then does the cathode need to be at a voltage that is below zero volt? The statement says cathode is given a 'negative' voltage. All of this is vague. KorgBoy (talk) 01:36, 16 June 2017 (UTC)

Turn-on methods section
I fixed the broken numbered list in the turn-on methods, but the following paragraph is mostly gibberish. Needs research and a rewrite. --Pstemari (talk) 09:07, 29 December 2011 (UTC)

Not a diode
An SCR is not a diode, as the erroneous definition that was added stated. They are neither functionally nor physically similar. An SCR when it is defined in terms of equivelant components is always defined as two BJT transistors. The two devices have nothing in common except that they are both multi-layer semiconductor devices. In this respect they differ in the number of layers, so that if you consider an SCR a diode, then a microprocessor is also a diode. In both cases using the device in nonstandard configurations can make them perform as a diode, but this is not typical or correct and will likely damage the SCR. AQBachler 15:25, 26 Nov 2003 (UTC)

Replace this article with a REDIRECT?
I think we should probably replace this article with a REDIRECT to the much-more-extensive article at Thyristor. How do folks feel about this?

Atlant 12:42, 25 Feb 2005 (UTC)

 * this page used to be a redirect (up until recently) to Thyristor. I think part of the difficulty was that some references define SCR and Thyristors as the same, while others don't. I'm ok with combining articles, might want to get imput from the persons who delt with this before. (see article history). Duk 16:49, 25 Feb 2005 (UTC)

I would say that the two (Thyristor and SCR) should be combined as they are two names for the same thing.Cadmium 22:38, 16 December 2005 (UTC)
 * While it is true that the terms SCR and thyristor are sometimes used synonymously, an SCR is a subset of the overall classification of thyristors. Other such types of thyristors are the GTO, MCT, the triac. It would not make sense to refer to, for example, refer to the GTO as a type of SCR. The common link for thyristors is that they are bistable devices with a pulsed gate requirement that turn on by pnpn regeneration. The SCR does not have a "controlled" turn off; the GTO does.Mak17f 23:13, 2 January 2006 (UTC)
 * Not all thyristors are SCRs - an SCR only conducts in one direction, but thyristors such as the triac will conduct in either direction. I checked with IEEE Std. 100 and they call the SCR a synonym for "reverse blocking thyristor". --Wtshymanski 18:58, 10 January 2006 (UTC)
 * Not all SCRs are made of Silicon either! The development of thyristors made from Silicon carbide has led some people to use the acronymn SCR to denote Semiconductor Controlled Rectifier. DFH 16:02, 7 May 2006 (UTC)
 * When referring to latchup in CMOS circuits, sources usually refer to parasitic thyristors, and hardly ever to parasitic SCRs. DFH 16:12, 7 May 2006 (UTC)

Anyone know what a "Jacobson circuit" is? ````Nick —Preceding unsigned comment added by 199.201.164.129 (talk) 14:10, 4 August 2008 (UTC)

A SCR is a type of thyristor, and I have seen the two terms used synonymously, I have also seen transistor used synonymously with semiconductor. A transistor is the most common type of semiconductor device, and SCR is the most common type of thyristor, but not all semiconductor devices are transistors, nor are all thyristors SCRs. —Preceding unsigned comment added by Gordongoude (talk • contribs) 04:24, 6 February 2010 (UTC)

I also think this article should be merged with the article on thyristors. The two are essentially the same thing. SCR is a term used mainly by General Electric; the rest of the world tends to use thyristor. Clampower (talk) 20:36, 19 September 2012 (UTC)

According to Bill Gutzwiller, he originally called it an SCR or simply "controlled rectifier". Thyristor was a name applied by others later, as usage spread. If there is a redirect or merge, shouldn't we keep the original name? Stevegt (talk) 18:12, 12 April 2014 (UTC)

unformated text removed from mainspace
Thyristor’s family : Power control device

Latching device

Break over voltage device.

Negative resistance device ( resistance is not follow by the ohm’s law )

FUNCTION	MAKE IT WORK	state

Power control device

Latching device

Break over voltage device.

Negative resistance device ( resistance is not follow by the ohm’s law )	-the load( light, motor, machine…) should be in series with anode –cathode(AK acts like open and closed switch) -the gate – cathode voltage (VGK ) is about 0.7v	The SCR is turn on – SCR IS FIRED. ANODE –CATHODE becomes closed switch.

SPECIFICATION :

VAK = voltage SCR when it is open = source voltage max.

IAK = current SCR when it closed ( max current)

VGK = Voltage gate – Cathode = 0.7V

VAK ( on )   = about 1v - 1.5v SCR IN DC CIRCUIT :

In Dc circuit, when Vgk = 0.7v then SCR is fired ( anode-cathode as a closed switch ) we can not turn off SCR because of the latch.However we can connect the external switch to reset SCR.

By pressing switch, the current Iak will decrease below a value called holding current Ih then SCR turn off.

Ir2 = (Vr2 – 0.7v)/ R2

SCR IN AC CIRCUIT ( LIGHT DIMMER CIRCUIT )

In AC circuit, we don’t have the latch circuit due to the change of alternating current.

By adjusting R2, we change the charging time to capacitor C, the time constant T = (R1 + R2)xC is called time delay angle or fired delay time which is the time to start firing SCR.

If R2 = max, then the time delay is longer. The light bulb became dimmest.

If R2 = min then the time delay will be shortest, the light became brightest.

EX :

R2 max = 75k then T = (15k + 75k ) x 0.47uF=42.3ms

R2 min = 25k then T = ( 15k + 25k) x 0.47uf=18.8ms

important speacification of scr ,triac
Give important speacification of scr ,triac —Preceding unsigned comment added by 117.200.192.109 (talk) 13:37, 18 June 2010 (UTC)

Article name
Why "Silicon controlled rectifier" redirects here, and not the other way around? SCR is a {Silicon {controlled {rectifier}}}: "controlled rectifier made of silicon", not a {{Silicon-controlled} {rectifier}}: "rectifier controlled by silicon". -- Mikhail Ryazanov (talk) 04:23, 21 March 2011 (UTC)

Agree - the hyphen should be dropped. Here's an ad from GE about their "revolutionary new controlled rectifier".

http://623f4c7f-a-62cb3a1a-s-sites.googlegroups.com/site/transistorhistory/Home/us-semiconductor-manufacturers/general-electric-history/GE%20Controlled%20Rectifier%201958.jpg?attachauth=ANoY7coK2Jm1dl9YptmNE_jmtzbUhEGpLQ7IUC-r2HAXprcZr-PBTSBkl450uL5xMiAfHD570vsuBWsbjVAhq42TlnyT7K2c-YOJT4C5ev4TY83jsWKii2I16qOqdK1zVCYPSgxjiUiJf2gG-AYNGte_fRJbXMEq8IkGP_5kZ8Vj3m1veGDJAA5yTV4p9GlgLxHZEgEkLHbb5e78o96wweJ2Yurhok2kM08rB7-XOOMbST7nRaZUVR0FxMR4r6etpXUDSuwq_bh2akDSdrCZh-GEWtjFVOxlQWd5NKfh2b0hIemxxx8FUEkEFtN0DwUSy4BnWMzML210D4RkOyde2nW2X-GkBNhnQg%3D%3D&attredirects=0

202.127.210.2 (talk) 08:20, 22 May 2012 (UTC)

Agree - the hyphen should be dropped. It is not a device controlled by silicon. Gc9580 (talk) 11:56, 19 April 2015 (UTC)

Does SCR stand for silicon controlled rectifier or semi-conductor rectifier?
Silicon controlled makes no sense to me as a name. The device is in fact a semi-conductor rectifier. I am familiar with the term SCR from numerous industrial projects I worked on and knew what the device did, although not my field of specialty.Phmoreno (talk) 01:50, 25 January 2012 (UTC)

It stands for Silicon Controlled Rectifier. Yes it is a semiconducter rectifier too, but so are ordinary diodes.

The "silicon controlled" part makes no sense because you're grouping the words wrong. It's not a rectifier that's "silicon controlled" but a "controlled rectifier" made of silicon, as opposed to one made of a gas-filled tube (thyratron)

It doesn't help that there's a hyphen in the Article Name that shouldn't be there. It should be removed.

The term "semiconductor-controlled rectifier" is non-standard and should be removed along with all other hyphens. — Preceding unsigned comment added by 2.123.172.140 (talk) 03:56, 14 March 2015 (UTC)

202.127.210.2 (talk) 08:13, 22 May 2012 (UTC)

"... is a four-layer solid statecurrent. "
Somebody's edit seems to have gone wrong.

Was that "current" supposed to be "device" or something else? — Preceding unsigned comment added by 173.79.157.238 (talk) 16:49, 25 July 2012 (UTC)

20 November edit
Is this edit a joke or not?! Anyone?Super48paul (talk) 10:16, 20 November 2013 (UTC)

 * Yes, but I didn't think it was funny. All edits made 2013-Nov-20 have been reverted. --DavidCary (talk) 14:35, 14 August 2014 (UTC)

Junction J1 J2 J3
This part I find confusing. Would appreciate a drawing or a better description explaining which junction is which. — Preceding unsigned comment added by 68.149.237.222 (talk) 05:25, 2 May 2018 (UTC)

India Education Program course assignment
This article was the subject of an educational assignment supported by Wikipedia Ambassadors through the India Education Program.

The above message was substituted from by PrimeBOT (talk) on 19:55, 1 February 2023 (UTC)

title: Talk:Silicon controlled rectifier


text:
Who Ate All the Pies?

"Who Ate All the Pies?" is a football chant sung by fans in the UK. It is usually sung to the tune of "Knees Up Mother Brown" and is aimed at overweight footballers, officials or other supporters.

Background and origin
The chant was first sung in 1894 by Sheffield United supporters, and directed at the club's goalkeeper William "Fatty" Foulke, who weighed over 300 lb. In his early career he played for Blackwell Colliery, subsequently playing for Sheffield United and Chelsea FC.

If the tune used was Knees up Mother Brown, then it is highly improbable that the chant originated with Foulke who retired in 1907 and died in 1916; Knees up Mother Brown originated in 1918. Also, Foulke weighed 178 lb in 1894, and according to sportswriters of the time, was nicknamed "the lengthy one" or "the octopus"; his weight gain came later.

The lyrics
The lyrics of the chant are:
 * Who ate all the pies?
 * Who ate all the pies?
 * You fat bastard,
 * You fat bastard,
 * You ate all the pies!

A variation replaces the second line with "The burgers and the fries."

Adoption and inspiration
Part of the song (the third line - "You fat bastard") has been adopted by Roy "Chubby" Brown as his anthem and is enthusiastically chanted by the audiences during his stage performances. In addition, the entire chant was sung by Brown and the audience at the end of his 2013 DVD release "Who Ate All the Pies?"

This line was also chanted at gigs by '90s indie band Carter The Unstoppable Sex Machine and included as the intro on their album 30 Something. It was chanted at their manager Jon Fat Beast, who had a tendency to appear on stage stripped to the waist, displaying his ample abdomen.

American rock band Faith No More released a live album You Fat Bastards: Live at the Brixton Academy, so named after the crowd were heard singing the chant at the band's show in April 1990.

The Vegetarian Society have used a variant of this, "Who ate all the peas?", as a slogan. They displayed it on promotional hoardings in football grounds as part of their "Men and Meat Campaign", intended to combat the idea that vegetarianism is unmanly.

The chant has been associated with the striker Micky Quinn, who played for six football clubs in the 1980s and 1990s. He was particularly identified with the chant following an incident in a match between Quinn's then club Newcastle United and Grimsby Town in March 1992, in which a fan threw a pie onto the pitch which Quinn promptly picked up and ate. The chant even formed the title for Quinn's autobiography, which was published in 2003.

During cricket matches, the chant is known to have been directed at players such as Shane Warne, by spectators belonging to the Barmy Army.

Wayne Shaw controversy
In a February 2017 incident dubbed "piegate", 23-stone Sutton United goalkeeper Wayne Shaw was fined and suspended by the FA for breaching gambling laws, after he ate a pie during a match and then admitted he saw there were odds of 8/1 on him doing so and tipped off his friends.

title: Who Ate All the Pies?


text:
Guanentá Province

Guanentá Province is a province in Santander Department, Colombia. The province was named after the Amerindian Chief Guanentá, leader of the Guanes, who were the original inhabitants of the region.

Geography
Guanentá Province is divided into seventeen municipalities:

Aratoca
A small town located within the Chicamocha Canyon. Its main attraction, other than fantastic views, is the colonial church, Nuestra Señora de las Nieves. The entire façade was built with locally sourced Guane stones. With its interior containing one large nave and four chapels. You will also discover a wonderful bell tower singing daily

Barichara
Is the jewel in the crown of the province of Guanentá. Its unspoiled colonial architecture, stone streets, and white houses that have preserved the old construction materials such as Tapia (compacted earth) and bahareque, make it one of the most beautiful towns in Colombia. Is very touristic place, so it makes a vibrant activity in its streets and squares, with boutique hotels, restaurants, and cafes of international stature.

Charalá
Called the Cradle of Freedom, due to the great support it provided in the Commune Revolution, Charalá has several places of interest, such as the Virolín natural park, the Tiger Cave (Cueva del Tigre), the chalice-shaped waterfall of Quebrada Tinagá, the church of Our Lady of Mongui (Nuestra Señora de Monguí), the House of Culture and the Archaeological Museum.

Curití
To one side of this town, you will find steep slopes flowing down into the Chicamocha Canyon and concluding in the Chicamocha River, at the base of the canyon. In this area there are many hiking trails along with the Cow Cave (Cueva de la Vaca). The cave is considered the most beautiful in Santander Department, with majestic formations and galleries that captivate its visitors with their exuberant beauty. The inhabitants grow the fique (Furcraea andina); a native plant, from which a fiber is used to create bags, belts, rugs, curtains, among many other products.

San Gil
San Gil is the capital of the Guanentá province and regarded as the most popular destination in Colombia for adventure and extreme sports, with elements of water, land, and air, all linked to nature tourism. It has an abundance of natural spaces filled with waterfalls, rivers, caves, mountains and the great Chicamocha canyon.

Socorro
The iconic town of Socorro is the location of the first steps towards independence, which was stretched into all the surrounding. Owing to the historic events that took place in Socorro, it was declared a National Cultural Interest Site in 1963.

Mogotes
For the Guane Indians, the definition of Mogotes is “Bathing in the stream that rises in the pit of the mountain”. It is surrounded by beautiful nature and a number of waterfalls with swimming holes are in close proximity. It was recognized as a garden town, and the sweet land of Santander Department. It is a very traditional Colombian country town, the weekend markets are full of the local farmers who have come to sell and buy their products.

Other Towns

 * Coromoro
 * Desert
 * Encino
 * Goatherd
 * Jordán
 * Ocamonte
 * Onzaga
 * Pinchote
 * San Joaquin
 * Valley of San Jose
 * Villanueva
 * Wooded hills

Hydrography

 * Fonce River born in the south of this province and it crosses it, from the south to the north west, gathering to his river steps such as: pienta, the mogoticos, broken of deer, and others, passes through towns such as Charalá, San Jose Valley (Valle de San José), Ocamonte, happens through territories of wooded hills. The urban helmet of San Gil, through near Pinchote, and ends to Suarez River.
 * Pienta Fonce River is one of the main effluents of Fonce River
 * Taquiza Fonce River: another one of the main tributaries of Fonce River
 * Mogoticos River: this tributary of Fonce River, as its name indicates, it comes from the Guanentino wooded hill municipality, and ends to Fonce River in the heat of the park Gallineral in San Gil.
 * Broken of Deer: this gorge comes from the municipality of Paramo, and ends at Fonce River, near the bridge of the valley, that unites San Gil and Paramo with the municipality of San Jose Valley (Valle de San José).

title: Guanentá Province


text:
Americans for Democratic Action

Americans for Democratic Action (ADA) is a liberal American political organization advocating progressive policies. ADA views itself as supporting social and economic justice through lobbying, grassroots organizing, research, and supporting progressive candidates.

Formation
The ADA grew out of a predecessor group, the Union for Democratic Action (UDA). The UDA was formed by former members of the Socialist Party of America and the Committee to Defend America by Aiding the Allies as well as labor union leaders, liberal politicians, theologians, and others who were opposed to the pacifism adopted by most left-wing political organizations in the late 1930s and early 1940s. It supported an interventionist, internationalist foreign policy and a pro-union, liberal domestic policy. It was also strongly anti-communist. It undertook a major effort to support left-wing Democratic members of Congress in 1946, but this effort was an overwhelming failure.

James Isaac Loeb – later an ambassador and diplomat in the John F. Kennedy administration – the UDA's executive director, advocated disbanding the UDA and forming a new, more broadly based, mass-membership organization. The ADA was formed on January 3, 1947, and the UDA shuttered.

Among ADA's founding members were leading anti-communist liberals from academic, political, and labor circles, including theologian Reinhold Niebuhr, historian Arthur M. Schlesinger Jr., Eleanor Roosevelt, union leader Walter Reuther, civil rights lawyer Joseph Rauh, and Hubert Humphrey. Its founders hoped to solidify a progressive, pragmatic, noncommunist "vital center" in mainstream politics, embodying Schlesinger's concept formulated in his 1949 book The Vital Center.

Action
On April 3, 1948, ADA declared its decision to support a Democratic Party ticket of General Dwight D. Eisenhower and Supreme Court Judge William O. Douglas over incumbent U.S. President Harry S. Truman. Truman lacked popular support, and the ADA succeeded in pushing Truman leftward on issues such as civil rights. It also led a full-scale attack on Progressive Party candidate and former US vice president Henry A. Wallace because of his opposition to the Marshall Plan and support for a more conciliatory relationship with the Soviet Union. The ADA portrayed Wallace and his supporters as dupes of the Communist Party. Adolf A. Berle Jr. and Franklin Delano Roosevelt Jr. believed that Eisenhower would accept the nomination. He did not.

ADA supported Truman after his victory in the 1948 election.

Although anti-communist, unlike other contemporary liberal groups like the Progressive Citizens of America (PCA), which supported cooperation with the Soviet Union, the ADA was still subject to significant McCarthyist scrutiny. The plight of the ADA during that period prompted Eleanor Roosevelt to accept a position as honorary chair of the organization in 1953, and in doing so, put Senator McCarthy in a position in which he would have had to "call her a communist as well" to continue his inquiries into the activities of the group. Because of her actions, many ADA leaders credited her with saving the organization.

In the early 1960s, ADA's influence peaked when a number of its key members (e.g. James Loeb, Arthur Schlesinger Jr.) were picked to join the administration of U.S. President John F. Kennedy. While active in liberal causes ranging from civil rights to Lyndon B. Johnson's Great Society reforms, by the mid-1960s the ADA's influence was on the wane. It was badly split over the Vietnam War: initially supporting Johnson's war policy, the ADA had come to oppose the war by early 1968. It endorsed founder Hubert Humphrey's presidential candidacy that year, but with "barely concealed ambivalence". After Richard Nixon's victory, the ADA was pushed to the political margins, overshadowed by more centrist groups like the Trilateral Commission and Coalition for a Democratic Majority.

Founders
Prominent founding members included:
 * Joseph Alsop
 * Stewart Alsop
 * Chester Bowles
 * Marquis Childs
 * David Dubinsky
 * Elmer Davis
 * John Kenneth Galbraith
 * Leon Henderson
 * Hubert Humphrey
 * James I. Loeb
 * Reinhold Niebuhr
 * Joseph P. Lash
 * Joseph L. Rauh Jr.
 * Walter Reuther
 * Eleanor Roosevelt
 * Franklin Delano Roosevelt Jr.
 * Arthur Schlesinger Jr.
 * John H. Sengstacke
 * James Wechsler
 * Walter White
 * Wilson W. Wyatt

In April 1948 at New York state convention, ADA elected the following new officers: Jonathan Bingham of Scarborough as chairman with vice chairmen Dr. William Lehman of Syracuse, Benjamin McLaurin of New York City, Howard Linsay of New York City, Jack Rubenstein (Textile Workers Union, CIO), and Charles Zimmerman (International Ladies' Garment Workers Union).

Chairs and presidents
Since 1947, ADA's leaders have been:

 * 1947–1948: Wilson Wyatt
 * 1948–1949: Leon Henderson
 * 1949–1950: Senator Hubert Humphrey
 * 1950–1953: Francis Biddle
 * 1954–1955: Arthur Schlesinger Jr.  and James E. Doyle (co-chairs)
 * 1955–1957: Joseph L. Rauh Jr.
 * 1957–1959: Robert R. Nathan
 * 1959–1962: Samuel H. Beer
 * 1961–1964: Paul Seabury
 * 1962–1965: John P. Roche
 * 1965–1967: Rep. Don Edwards
 * 1967–1969: John Kenneth Galbraith
 * 1970–1971: Joseph Duffey
 * 1971–1973: Rep. Allard K. Lowenstein
 * 1974–1976: Rep. Donald M. Fraser
 * 1976–1978: Senator George McGovern
 * 1978–1981: Rep. Patsy T. Mink
 * 1981–1984: Rep. Robert F. Drinan, S.J.
 * 1984–1986: Rep. Barney Frank
 * 1986–1989: Rep. Ted Weiss
 * 1989–1991: Rep. Charles B. Rangel
 * 1991–1993: Senator Paul D. Wellstone
 * 1993–1995: Rep. John Lewis
 * 1995–1998: Jack Sheinkman
 * 1998–2000: Rep. Jim Jontz
 * 2000–2008: Rep. Jim McDermott
 * 2008–2010: Richard Parker
 * 2010–2016: Rep. Lynn Woolsey
 * 2017–2018: State Senator Daylin Leach
 * 2018–: State Senator Art Haywood

Voting records
ADA ranks legislators, identifies key policy issues, and tracks how members of Congress vote on these issues. The annual ADA Voting Record gives each member a Liberal Quotient (LQ) rating from 0, meaning complete disagreement with ADA policies, to 100, meaning complete agreement with ADA policies. A score of 0 is considered conservative and a score 100 is considered liberal. The LQ is obtained by evaluating an elected official's votes on 20 key foreign and domestic social and economic issues chosen by the ADA's Legislative Committee. Each vote given a score of either 5 or 0 points, depending on whether the individual voted with or against the ADA's position, respectively. Absent voters are also given a score of 0 for the vote.

title: Americans for Democratic Action


text:
Worthington

Worthington may refer to:

People

 * Worthington (surname)
 * Worthington family, a British noble family

Businesses

 * Worthington Brewery, also known as Worthington's
 * Worthington Corporation, founded as a pump manufacturer in 1845, later a diversified manufacturer, merged into Studebaker-Worthington in 1967
 * Worthington Industries, a metals manufacturing company founded in 1955

Canada

 * Worthington, Ontario

England

 * Worthington, Greater Manchester
 * Worthington, Leicestershire

United States

 * Worthington, Indiana
 * Worthington, Iowa
 * Worthington, Kentucky
 * Worthington, Louisville, Kentucky, a neighborhood
 * Worthington, Massachusetts
 * Worthington, Minnesota, in Nobles County
 * Worthington Township, Nobles County, Minnesota
 * Worthington, Missouri
 * Worthington, Ohio, in Franklin County
 * Worthington Township, Richland County, Ohio
 * Worthington, Pennsylvania
 * Worthington, West Virginia

Other

 * Worthington, a clothing line from J. C. Penney
 * Worthington College, a fictional school in the television show Dawson's Creek
 * Worthington Peak, a mountain in Nevada

title: Worthington


text:
Talk:Mercury-Redstone 4

Launch time
I can only find a launch time of 12:20 UTC -no seconds listed and so put landing at 15 min 37 sec. past that. Rmhermen 15:42, Nov 26, 2003 (UTC)

 * I found something saying it was exactly on the minute, but it was like such for Mercury 5 and Mercury 3 as well (especially when it seemed to have a conflicting time for Mercury 5), so I removed the exact time. I suppose it's fine as it is. -- Pipian

 * On the REFERENCE list near the bottom of the Wikipedia Mercury 4 webpage is a reference manual link called - "Results Of The Second U.S. Manned Suborbital Spaceflight July 21, 1961 (NASA)". PDF Page 33 (manual page 31) of this reference lists MR-3 launch time as 9:34:13 e.s.t. and MR-4 launch time as 7:20:36 e.s.t. Rusty 20:12, 29 Jun 2004 (UTC)

"Mrs. Grissom was not invited to the White House as per the forming tradition with previous astronaut wives upon successful mission completion." Wasn't there only one astronaut (and hence only one wife) who had completed a successful mission at this stage (Shepherd in Mercury 3)? -R. fiend 17:58, 23 Jul 2004 (UTC)

 * Hence "forming tradition"? Didn't NASA have a SOP worked up? (Everything else did...).

 * For what it's worth, didn't LB7 fly atop a Redstone IV? Trekphiler 11:42, 30 December 2005 (UTC)

Omission
I don't see the name of the recovery ship, CV-15 Randolph, or the helo unit that attempted the pickup of Liberty Bell 7. Can somebody confirm & include? Trekphiler 01:31, 31 December 2005 (UTC)

 * I can confirm from This New Ocean that the recovery ship was Randolph. I haven't been able to identify any of the destroyers or the recovery squadron. There were (at least) two Marine helicopters, side-numbers 30 and 32 and tail code ET(?), and one Navy helicopter, side-number 52 and tail code unclear, if those mean anything.
 * For MR-3, the helicopter group was MAG-26 - this used a different carrier, Lake Champlain, but they're described as "a veteran recovery unit" and it's possible they were embarked on whichever carrier was used. Certainly one of the crewmembers involved had been in the Shepard rescue. Shimgray | talk | 23:38, 7 January 2006 (UTC)

Jim Lewis, the helicopter pilot who cut Liberty Bell 7 loose, was from HMR(L) 261, based at New River, North Carolina. The other ships involved in the recovery effort were the USS Conway (DDE 607), USS Cony (DDE 508), and the USS Lowry (DD770), as well as a tracking ship called "Atlantic Ship," stationed somewhere along the flight path. Source: C. Newport 69.138.184.13 01:30, 25 January 2007 (UTC)

 * Thanks for the help. Sn30 matches with the film I've seen, & Lowry sounds familiar. I'd still raise Q if this should be included. Comment? Trekphiler 22:02, 10 February 2007 (UTC)

Proposed Move
I have proposed that all Mercury missions are re-named. This will affect this page. So they can be discussed together on one page, I've set up a subpage of my user talk page for discussion of the moves. -- GW_Simulations |User Page 20:38, 2 June 2006 (UTC)

Explosive Device
"After Liberty Bell 7 was secured in the deck of the recovery ship, experts removed and disposed of an explosive device that was supposed to detonate in the event of the capsule's sinking but which failed to explode." The explosive device was called a SOFAR bomb, Sound Fixing and Rangeing, made by the Bermite Corporation in Santa Clarita, CA. The device was a one pound (net explosive weight) barometrically fired signaling device meant to alert recovery vessels in the area through their sonar. The SOFAR bomb would arm as it sank through approximately 3,500 feet of sea water, and fire at approximatelly 4,000 feet. There were two on the capsul: one in a pocket on the main parachute risers and one behind the instrument bulkhead. The one on the parachute risers would be ejected as the parachute deployed, fall to the ocean surface, sink, arm and detonate thus alerting the recovery ships through their sonar on what bearing the capsul would soon land. The second SOFAR bomb was intended to detonate if the capsul sank giving an indication where it sank and destroying the instrument bulkhead thus insuring it sank so no unfriendly nation could recover it.

Source: I am the Explosive Ordnance Disposal (EOD) Technician who was on the recovery ship and found and disposed of the second dud SOFAR bomb in the recovered capsul. See the Discovery Channel documentary.

Tedious writing style
Has this been written by a 10 year old ?

 * No, a NASA historian... 68.39.174.238 11:40, 6 July 2007 (UTC)

Location of capsule?
The caption of the photo of Liberty Bell 7 says it is at KSC. It is actually at the Kansas location, isn't it? Bubba73 (You talkin' to me?), 20:57, 24 June 2010 (UTC)

Ownership of spacecrafts
I would recheck the sentence "Liberty Bell 7 is the only flown American spacecraft owned by a museum other than the National Air and Space Museum." in the paragraph "Recovery of Liberty 7". I do not know the ownership claims exactly, but the California ScienCenter could be another museum owning a flown American spacecraft, which is Space Shuttle Endeavour. The sentence might be obsolete now. 85.180.58.156 (talk) 16:12, 13 September 2011 (UTC)

Suit and cabin temperature
Ninety-seven degrees Fahrenheit is nearly body temperature. Fifty-seven degrees would be perceived as a chilly room. Modern space suits are cooled (sometimes with a water-cooled undergarment) because the suit can get uncomfortable after a long period of wear. My guess is the original figures were right, with the cooler temperature inside the suit. But we shouldn't have to guess; we need to find a citation, perhaps in This New Ocean. JustinTime55 (talk) 15:35, 26 November 2013 (UTC)

 * 57 sounds right, given the amout of body head an astronaut would generate, plus the heat from the elecronics. After all, that's on the pad, not in flight.  TREK philer   any time you're ready, Uhura  16:21, 26 November 2013 (UTC)

 * This is moot; we have an even bigger problem. The numbers as given, in flight, are correct (i.e. 57.5 suit, 97 cabin); in fact, several sections have been directly copy-pasted from This New Ocean (!) JustinTime55 (talk) 16:29, 26 November 2013 (UTC)

 * Perhaps what was meant was that the cooling fluid to the suit was at 57 degrees, not that the "inside of the suit" right next to the body was 57.73.81.159.141 (talk) 06:26, 29 August 2016 (UTC)

 * 57 degrees F. inside the entire spacesuit would have been felt as very cold an uncomfortable, indeed. The astronaut would have been shivering at that temperature!24.156.77.8 (talk) 18:39, 30 July 2018 (UTC)

Contradiction
It's not clear to me how sliced off does not contradict pulled asunder. Could you explain your reasoning here please? --catslash (talk) 21:46, 17 December 2014 (UTC)

 * Sheared doesn't necessarily mean sliced; the This New Ocean source actually says: "When a mild detonating fuse, placed in a groove around each bolt, was energized, the bolts were sheared simultaneously and the hatch sprang open." There was not enough explosive to fragment the bolts (which was not the intent); it simply cracks and separates at one point, as if it had been "sliced off". The phrase "sheared off" is commonly used (at least in the USA) to describe bolts that fail like this. (I'm sorry if usage is different in the UK.) (Even though, from an engineering standpoint, the term isn't precisely correct, because the bolts fail from tensile (axial) stress, while the term "shear" refers to stress applied crosswise (as in slicing off).) "Sheared" is terminology commonly understood in the semitechnical, lay public, while "pulled apart" is inaccurate. JustinTime55 (talk) 13:20, 19 December 2014 (UTC)

 * Correct!24.156.77.8 (talk) 18:41, 30 July 2018 (UTC)

Purpose of the mission
What was the purpose of this mission? Was its purpose different from that of MR-4? Were they just getting more experience doing the same thing?CountMacula (talk) 01:56, 9 February 2015 (UTC)
 * According to the NASA's press kit, the reason was to gain more experience and test some of the spaceship modifications. see here. --Golan's mom (talk) 10:55, 27 August 2017 (UTC)

External links modified (January 2018)
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Mission Names
I remember watching this flight as a ten year old on a TV set up in a classroom, as I had the first Mercury flight. Not ever in my life have I heard or read Liberty Bell 7 refereed to as Spacecraft #11. Who does anybody think would be searching "spacecraft #11", not "liberty Bell 7? What propose does it serve? Why confuse people? Jackhammer111 (talk) 04:36, 25 April 2018 (UTC)

 * I agree: All of this nonsense about #11 is nothing but confusing the situation. #11 was merely a manufacturing number assigned by McDonnell Aircraft for use inside of its factory in suburban St. Louis, and that number is meaningless everywhere else.24.156.77.8 (talk) 18:47, 30 July 2018 (UTC)

title: Talk:Mercury-Redstone 4


text:
Itasca

Itasca is a word coined by Henry Schoolcraft and may refer to:

 * Lake Itasca, the source of the Mississippi River

Places in the United States

 * Itasca County, Minnesota
 * Itasca Township, Clearwater County, Minnesota
 * Itasca Township, Sherman County, Kansas
 * Itasca State Park, Minnesota
 * Itasca, Illinois
 * Itasca, Texas
 * Itasca Village, a former settlement in Anoka County, Minnesota
 * South Itasca, Wisconsin
 * Itascatown, a historical settlement on Howland Island named after the United States Coast Guard Cutter Itasca (see below)
 * Itaska Street (St. Louis), a road in St. Louis, Missouri

Ships in the United States

 * USCGC Itasca (1929), a United States Coast Guard cutter in commission from 1930 to 1941 and from 1946 to 1950, famous for her role during the disappearance of Amelia Earhart in 1937
 * USS Itasca, the name of more than one United States Navy ship

Other

 * Itasca Phasar, a brand of recreational vehicles produced by Winnebago Industries
 * Itasca, the pseudonym of American musician Kayla Cohen, who released the 2024 album Imitation of War

title: Itasca