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https://en.wikipedia.org/wiki/Conchoid
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Conchoid can refer to:
Conchoid (mathematics), an equation of a curve discovered by the mathematician Nicomedes
Conchoidal fracture, a breakage pattern characteristic to certain glasses and crystals
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https://en.wikipedia.org/wiki/CAST-256
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In cryptography, CAST-256 (or CAST6) is a symmetric-key block cipher published in June 1998. It was submitted as a candidate for the Advanced Encryption Standard (AES); however, it was not among the five AES finalists. It is an extension of an earlier cipher, CAST-128; both were designed according to the "CAST" design methodology invented by Carlisle Adams and Stafford Tavares. Howard Heys and Michael Wiener also contributed to the design.
CAST-256 uses the same elements as CAST-128, including S-boxes, but is adapted for a block size of 128 bits – twice the size of its 64-bit predecessor. (A similar construction occurred in the evolution of RC5 into RC6). Acceptable key sizes are 128, 160, 192, 224 or 256 bits. CAST-256 is composed of 48 rounds, sometimes described as 12 "quad-rounds", arranged in a generalized Feistel network.
In RFC 2612, the authors state that, "The CAST-256 cipher described in this document is available worldwide on a royalty-free and licence-free basis for commercial and non-commercial uses."
Currently, the best public cryptanalysis of CAST-256 in the standard single secret key setting that works for all keys is the zero-correlation cryptanalysis breaking 28 rounds with 2246.9 time and 298.8 data.
See also
AES process
References
External links
CAST-256 by John J. G. Savard
256bit Ciphers - CAST256 Reference implementation and derived code
Standard Cryptographic Algorithm Naming: CAST-256
Block ciphers
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https://en.wikipedia.org/wiki/Thompson%20groups
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In mathematics, the Thompson groups (also called Thompson's groups, vagabond groups or chameleon groups) are three groups, commonly denoted , that were introduced by Richard Thompson in some unpublished handwritten notes in 1965 as a possible counterexample to the von Neumann conjecture. Of the three, F is the most widely studied, and is sometimes referred to as the Thompson group or Thompson's group.
The Thompson groups, and F in particular, have a collection of unusual properties that have made them counterexamples to many general conjectures in group theory. All three Thompson groups are infinite but finitely presented. The groups T and V are (rare) examples of infinite but finitely-presented simple groups. The group F is not simple but its derived subgroup [F,F] is and the quotient of F by its derived subgroup is the free abelian group of rank 2. F is totally ordered, has exponential growth, and does not contain a subgroup isomorphic to the free group of rank 2.
It is conjectured that F is not amenable and hence a further counterexample to the long-standing but recently disproved
von Neumann conjecture for finitely-presented groups: it is known that F is not elementary amenable.
introduced an infinite family of finitely presented simple groups, including Thompson's group V as a special case.
Presentations
A finite presentation of F is given by the following expression:
where [x,y] is the usual group theory commutator, xyx−1y−1.
Although F has a finite presentatio
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https://en.wikipedia.org/wiki/Thompson%20group
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In mathematics, the term Thompson group or Thompson's group can refer to either
The finite Thompson sporadic group Th studied by John G. Thompson
The finite Thompson subgroup of a p-group, the subgroup generated by the abelian subgroups of maximal order.
"Thompson subgroup" can also mean an analogue of the Weyl group used in the classical involution theorem
The infinite Thompson groups F, T and V studied by the logician Richard Thompson.
Outside of mathematics, it may also refer to
Thompson Group Inc.
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https://en.wikipedia.org/wiki/Jan%20M%C3%BChlstein
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Jan Mühlstein (born 3 July 1949) is a journalist, German Jewish activist and the former chair of the Union of Progressive Jews in Germany.
Life
Jan Mühlstein was born on 3 July 1949 in Most, Czechoslovakia. He grew up in a German-speaking Jewish family, which traditionally practised Liberal Judaism. In 1967, he began studying physics at the Charles University in Prague. After the defeat of the reformation movement known as the Prague Spring, in which Mühlstein participated actively, he emigrated to West Germany in 1969. From 1970 onwards, he studied physics at the Ludwig Maximilian University of Munich and completed a Ph.D. in theoretical quantum optics in 1977. During the next four years, he worked in the leadership of project energy research of the nuclear energy research facility in Jülich. Since 1982, Mühlstein has been working as a business journalist in Munich and is deputy chief editor of a journal covering the economics of the energy market.
Between 1977 and 1978, Mühlstein was a board member of the West German section of Amnesty International. He is a co-founder of the Liberal Jewish Community Munich "Beth Shalom", whose chair he was until 2005. He was again elected as chair of Beth Shalom in May 2011. From 1999 until 2011, he was the chair of the Union of Progressive Jews in Germany. Mühlstein is particularly committed to promote religious plurality in Judaism.
Mühlstein is married to Dr. Verena Mühlstein (born 1953), author of a biography about Albert Schweitze
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https://en.wikipedia.org/wiki/Hans%20Freudenthal
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Hans Freudenthal (17 September 1905 – 13 October 1990) was a Jewish German-born Dutch mathematician. He made substantial contributions to algebraic topology and also took an interest in literature, philosophy, history and mathematics education.
Biography
Freudenthal was born in Luckenwalde, Brandenburg, on 17 September 1905, the son of a Jewish teacher. He was interested in both mathematics and literature as a child, and studied mathematics at the University of Berlin beginning in 1923. He met L. E. J. Brouwer in 1927, when Brouwer came to Berlin to give a lecture, and in the same year Freudenthal also visited the University of Paris. He completed his thesis work with Heinz Hopf at Berlin, defended a thesis on the ends of topological groups in 1930, and was officially awarded a degree in October 1931. After defending his thesis in 1930, he moved to Amsterdam to take up a position as assistant to Brouwer. In this pre-war period in Amsterdam, he was promoted to lecturer at the University of Amsterdam, and married his wife, Suus Lutter, a Dutch teacher.
Although he was a German Jew, Freudenthal's position in the Netherlands insulated him from the anti-Jewish laws that had been passed in Germany beginning with the Nazi rise to power in 1933. However, in 1940 the Germans invaded the Netherlands, following which Freudenthal was suspended from duties at the University of Amsterdam by the Nazis. In 1943 Freudenthal was sent to a labor camp in the village of Havelte in the Netherla
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https://en.wikipedia.org/wiki/MISTY1
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In cryptography, MISTY1 (or MISTY-1) is a block cipher designed in 1995 by Mitsuru Matsui and others for Mitsubishi Electric.
MISTY1 is one of the selected algorithms in the European NESSIE project, and has been among the cryptographic techniques recommended for Japanese government use by CRYPTREC in 2003; however, it was dropped to "candidate" by CRYPTREC revision in 2013. However, it was successfully broken in 2015 by Yosuke Todo using integral cryptanalysis; this attack was improved in the same year by Achiya Bar-On.
"MISTY" can stand for "Mitsubishi Improved Security Technology"; it is also the initials of the researchers involved in its development: Matsui Mitsuru, Ichikawa Tetsuya, Sorimachi Toru, Tokita Toshio, and Yamagishi Atsuhiro.
MISTY1 is covered by patents, although the algorithm is freely available for academic (non-profit) use in RFC 2994, and there's a GPLed implementation by Hironobu Suzuki (used by, e.g. Scramdisk).
Security
MISTY1 is a Feistel network with a variable number of rounds (any multiple of 4), though 8 are recommended. The cipher operates on 64-bit blocks and has a key size of 128 bits. MISTY1 has an innovative recursive structure; the round function itself uses a 3-round Feistel network. MISTY1 claims to be provably secure against linear and differential cryptanalysis.
KASUMI
KASUMI is a successor of the MISTY1 cipher which was supposed to be stronger than MISTY1 and has been adopted as the standard encryption algorithm for European mobile
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https://en.wikipedia.org/wiki/Audio%20processing
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Audio processing may refer to:
Audio signal processing
Auditory system, particularly in the context of auditory processing disorder
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https://en.wikipedia.org/wiki/Acylation
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In chemistry, acylation is a broad class of chemical reactions in which an acyl group () is added to a substrate. The compound providing the acyl group is called the acylating agent. The substrate to be acylated and the product include the following:
alcohols, esters
amines, amides
arenes, ketones
A particularly common type of acylation is acetylation, the addition of the acetyl group. Closely related to acylation is formylation, which employ sources of "HCO+ in place of "RCO+".
Examples
Because they form a strong electrophile when treated with Lewis acids, acyl halides are commonly used as acylating agents. For example, Friedel–Crafts acylation uses acetyl chloride () as the agent and aluminum chloride () as a catalyst to add an acetyl group to benzene:
This reaction is an example of electrophilic aromatic substitution.
Acyl halides and acid anhydrides of carboxylic acids are also common acylating agents. In some cases, active esters exhibit comparable reactivity. All react with amines to form amides and with alcohols to form esters by nucleophilic acyl substitution.
Acylation can be used to prevent rearrangement reactions that would normally occur in alkylation. To do this an acylation reaction is performed, then the carbonyl is removed by Clemmensen reduction or a similar process.
Acylation in biology
Protein acylation is the post-translational modification of proteins via the attachment of functional groups through acyl linkages. Protein acylation has been observe
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https://en.wikipedia.org/wiki/Robotics%20Institute
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The Robotics Institute (RI) is a division of the School of Computer Science at Carnegie Mellon University in Pittsburgh, Pennsylvania, United States. A June 2014, the article in Robotics Business Review magazine calls it "the world's best robotics research facility" and a "pacesetter in robotics research and education."
The Robotics Institute focuses on bringing robotics into everyday activities. Its faculty members and graduate students examine a variety of fields, including space robotics, medical robotics, industrial systems, computer vision and artificial intelligence, and they develop a broad array of robotics systems and capabilities.
Established in 1979 by Raj Reddy, the RI was the first robotics department at any U.S. university. In 1988, CMU became the first university in the world offering a Ph.D. in Robotics.
In 2012, the faculty, staff, students and postdocs numbered over 500, and the RI annual budget exceeded $65M, making the RI one of the largest robotics research organizations in the world.
The RI occupies facilities on the Carnegie Mellon main campus as well as in the Lawrenceville and Hazelwood neighborhoods of Pittsburgh, totaling almost 200,000 sq. ft of indoor space and 40 acres of outdoor test facilities.
Major centers
The National Robotics Engineering Center (NREC) was established in 1996 as the commercial arm of the RI, with the intention of applying robotic technology to commercial and defense applications. It has partnered with more than 300 co
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https://en.wikipedia.org/wiki/1952%20in%20science
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The year 1952 in science and technology involved some significant events, listed below.
Biology
August 1 – Around 9 o'clock AM Pacific Time Zone, the San Benedicto rock wren goes extinct as its island home is smothered in a massive volcanic eruption.
August 14 – Alan Turing's paper "The Chemical Basis of Morphogenesis" is published, putting forward a reaction–diffusion hypothesis of pattern formation, considered a seminal piece of work in morphogenesis.
August 28 – Alan Hodgkin and Andrew Huxley publish the Hodgkin–Huxley model of action potentials in neurons of the squid giant axon.
September 20 – Publication of the paper on the Hershey–Chase experiment showing conclusively that DNA, not protein, is the genetic material of bacteriophages.
October – Danish virologist Preben von Magnus publishes his observation of the von Magnus phenomenon producing defective interfering particles.
Biochemists Jack Gross and Rosalind Pitt-Rivers discover the thyroid hormone triiodothyronine.
The Braeburn apple cultivar is discovered as a chance seedling in New Zealand.
Last confirmed sighting of the Caribbean monk seal, at Serranilla Bank, between Jamaica and Nicaragua.
Chemistry
Soviet scientists L. V. Radushkevich and V. M. Lukyanovich publish images of carbon nanotubes.
Computer science
The first autocode and its compiler are developed by Alick Glennie for the Manchester Mark 1 computer, considered as the first working high-level compiled programming language.
History of scien
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https://en.wikipedia.org/wiki/Calculus%20of%20constructions
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In mathematical logic and computer science, the calculus of constructions (CoC) is a type theory created by Thierry Coquand. It can serve as both a typed programming language and as constructive foundation for mathematics. For this second reason, the CoC and its variants have been the basis for Coq and other proof assistants.
Some of its variants include the calculus of inductive constructions (which adds inductive types), the calculus of (co)inductive constructions (which adds coinduction), and the predicative calculus of inductive constructions (which removes some impredicativity).
General traits
The CoC is a higher-order typed lambda calculus, initially developed by Thierry Coquand. It is well known for being at the top of Barendregt's lambda cube. It is possible within CoC to define functions from terms to terms, as well as terms to types, types to types, and types to terms.
The CoC is strongly normalizing, and hence consistent.
Usage
The CoC has been developed alongside the Coq proof assistant. As features were added (or possible liabilities removed) to the theory, they became available in Coq.
Variants of the CoC are used in other proof assistants, such as Matita and Lean.
The basics of the calculus of constructions
The calculus of constructions can be considered an extension of the Curry–Howard isomorphism. The Curry–Howard isomorphism associates a term in the simply typed lambda calculus with each natural-deduction proof in intuitionistic propositional logic.
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https://en.wikipedia.org/wiki/1950%20in%20science
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The year 1950 in science and technology included some significant events.
Astronomy and space sciences
Dutch astronomer Jan Oort postulates the existence of an orbiting cloud of planets (the Oort cloud) at the outermost edge of the Solar System.
Enrico Fermi discusses the Fermi paradox.
Biology
Melvin Calvin, James Bassham, and Andrew Benson at the University of California, Berkeley, discover the Calvin cycle in photosynthesis.
Entomologist Willi Hennig publishes Grundzüge einer Theorie der phylogenetischen Systematik in East Germany, pioneering the study of cladistics.
Full-scale release of myxomatosis for control of the Australian rabbit population.
Chemistry
February 9 – Californium, a radioactive actinide transuranium element, is first synthesized by Stanley G. Thompson, Kenneth Street, Jr., Albert Ghiorso and Glenn T. Seaborg at the University of California, Berkeley.
Computer science
March – Publication of Claude Shannon's paper "Programming a Computer for Playing Chess", seminal in the development of computer chess and introducing the Shannon number.
April – Publication of Richard Hamming's paper "Error detecting and error correcting codes", seminal in the construction of error detection and correction codes and from which Hamming code and the Hamming distance derive.
October – Publication of Alan Turing's paper "Computing Machinery and Intelligence", seminal in the study of artificial intelligence and presenting the Turing test.
Mathematics
John Forbes
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https://en.wikipedia.org/wiki/1949%20in%20science
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The year 1949 in science and technology involved some significant events, listed below.
Astronomy and space exploration
June 14 – Albert II, a rhesus monkey, becomes the first mammal in space, in a U.S.-launched V-2 rocket, reaching an altitude of 83 miles (134 km) but dying on impact after a parachute failure.
Chemistry
Radiocarbon dating technique discovered by Willard Libby and his colleagues at the University of Chicago—work for which Libby will receive the Nobel prize in 1960.
A group including Dorothy Hodgkin publish the three-dimensional molecular structure of penicillin, demonstrating that it contains a β-lactam ring.
Computer science
April – Manchester Mark 1 computer operable at the University of Manchester in England.
May 6 – EDSAC, the first practicable stored-program computer, runs its first program at University of Cambridge in England, to calculate a table of squares.
Earth sciences
August 5 – Ambato earthquake in Ecuador, measuring 6.8 on the Richter magnitude scale.
Patomskiy crater in Siberia is discovered by Russian geologist Vadim Kolpakov.
History of science
Herbert Butterfield publishes The Origins of Modern Science, 1300-1800.
Mathematics
Ákos Császár discovers the Császár polyhedron.
D. R. Kaprekar discovers the convergence property of the number 6174.
Medicine
The use of lithium salts to control mania is rediscovered by Australian psychiatrist John Cade, the first mood stabilizer.
First implant of intraocular lens, by Sir Harold Rid
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https://en.wikipedia.org/wiki/1948%20in%20science
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The year 1948 in science and technology involved some significant events, listed below.
Astronomy and space science
February 16 – Miranda, innermost of the large moons of Uranus, is discovered by Gerard Kuiper from the McDonald Observatory in Texas.
October 10 – An R-1 (missile) on test becomes the first Soviet launch to enter space.
Biology
August 7 – Teaching and research in Mendelian genetics is prohibited in the Soviet Union in favour of Lysenkoist theories of the inheritance of acquired characteristics.
October 5 – Delegates to a conference organised by Sir Julian Huxley at Fontainebleau agree to formation of the International Union for Conservation of Nature.
November 20 – The South Island takahē, a flightless bird generally thought to have been extinct for fifty years, is rediscovered by Geoffrey Orbell near Lake Te Anau in the South Island of New Zealand.
Last recorded sighting of the Caspian tiger in Kazakhstan.
Publication of Fairfield Osborne's Our Plundered Planet, a Malthusian critique of human environmental destruction.
Computer science
May 12 – World's first stored-program computer operates, the mechanical ARC (Automatic Relay Calculator) at Birkbeck College, University of London (largely built by Kathleen Booth).
June 21 – World's first working program run on an electronic stored-program computer, the Manchester Baby (written by Tom Kilburn).
July–October – Claude E. Shannon publishes "A Mathematical Theory of Communication" in Bell System Technic
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https://en.wikipedia.org/wiki/1943%20in%20science
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The year 1943 in science and technology involved some significant events, listed below.
Biology
July 21 – Living specimens of Metasequoia glyptostroboides, the Dawn Redwood, previously known only as a Mesozoic fossil, are located in China.
The University of Oxford acquires the nearby Wytham Woods which become an important centre for research into ecology in England.
David Lack's study The Life of the Robin is published in England.
Computer science
March–December – Construction of British prototype Mark I Colossus computer, the world's first totally electronic programmable computing device, at the Post Office Research Station, Dollis Hill, to assist in cryptanalysis at Bletchley Park.
May 17 – The United States Army contracts with the University of Pennsylvania's Moore School to develop the ENIAC.
Earth sciences
February 20 – The cinder cone volcano Parícutin begins to appear in Mexico, giving volcanologists an unusual opportunity to observe its complete life cycle.
Nuclear physics
January 1 – Project Y, the Manhattan Project's secret laboratory at Los Alamos, New Mexico, for development and production of the first atomic bombs under the direction of J. Robert Oppenheimer, begins operations.
Pharmacology
March 23 – The drugs Vicodin and Lortab are made in Germany.
October 19 – The antibiotic streptomycin (the first antibiotic remedy for tuberculosis) is first isolated by Albert Schatz in the laboratory of Selman Abraham Waksman at Rutgers University in the United
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https://en.wikipedia.org/wiki/Annals%20of%20Human%20Genetics
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The Annals of Human Genetics is a bimonthly peer-reviewed scientific journal covering human genetics. It was established in 1925 by Karl Pearson as the Annals of Eugenics, with as subtitle, Darwin's epigram "I have no Faith in anything short of actual measurement and the rule of three". The journal obtained its current name in 1954 to reflect changing perceptions on eugenics.
History
Annals of Eugenics
Pearson edited the journal from 1925 to 1933. In a brief valedictory letter published at the time of his resignation, Pearson wrote that he had fallen short of his aspirations, having published only five volumes over eight years due to the limited financial resources of the Galton Laboratory. He reaffirmed his belief that eugenics was worthy as a subject of academic study and as a source of public policy, but warned against hastily adopting eugenic legislation, noting that the field contained too many theories weakly supported by anecdote or opinion.
Ronald Fisher took over as editor in 1934 and with Humphry Rolleston, Reginald Ruggles Gates and Dr John Alexander Fraser Roberts on the editorial board. The journal focused more clearly on genetics and mathematical statistics.
Ethical issues with rejection of an article related to China
In June 2021, the Annals refused to publish an article, coauthored by David Curtis, its editor-in-chief at the time, suggesting that academic journals should take a stance against China’s human rights violations in Xinjiang. The journal ha
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https://en.wikipedia.org/wiki/Square%20%28cipher%29
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In cryptography, Square (sometimes written SQUARE) is a block cipher invented by Joan Daemen and Vincent Rijmen. The design, published in 1997, is a forerunner to Rijndael, which has been adopted as the Advanced Encryption Standard. Square was introduced together with a new form of cryptanalysis discovered by Lars Knudsen, called the "Square attack".
The structure of Square is a substitution–permutation network with eight rounds, operating on 128-bit blocks and using a 128-bit key.
Square is not patented.
References
External links
SCAN's entry for Square
Block ciphers
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https://en.wikipedia.org/wiki/Intransitivity
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In mathematics, intransitivity (sometimes called nontransitivity) is a property of binary relations that are not transitive relations. This may include any relation that is not transitive, or the stronger property of antitransitivity, which describes a relation that is never transitive.
Intransitivity
A relation is transitive if, whenever it relates some A to some B, and that B to some C, it also relates that A to that C. Some authors call a relation if it is not transitive, that is, (if the relation in question is named )
This statement is equivalent to
For example, consider the relation R on the integers such that a R b if and only if a is a multiple of b or a divisor of b. This relation is intransitive since, for example, 2 R 6 (2 is a divisor of 6) and 6 R 3 (6 is a multiple of 3), but 2 is neither a multiple nor a divisor of 3. This does not imply that the relation is (see below); for example, 2 R 6, 6 R 12, and 2 R 12 as well.
As another example, in the food chain, wolves feed on deer, and deer feed on grass, but wolves do not feed on grass. Thus, the relation among life forms is intransitive, in this sense.
Another example that does not involve preference loops arises in freemasonry: in some instances lodge A recognizes lodge B, and lodge B recognizes lodge C, but lodge A does not recognize lodge C. Thus the recognition relation among Masonic lodges is intransitive.
Antitransitivity
Often the term is used to refer to the stronger property of antitransiti
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https://en.wikipedia.org/wiki/Pod
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Pod or POD may refer to:
Biology
Pod (fruit), a type of fruit of a flowering plant
Husk or pod of a legume
Pod of whales or other marine mammals
"-pod", a suffix meaning "foot" used in taxonomy
Electronics and computing
Proper orthogonal decomposition in the field of numerical simulation
Plain old data in computing, data distinct from an object
Plain Old Documentation, a documentation tool for the computer language Perl
Point of delivery (networking)
Pseudo open drain, an electronics interface technology
Personal online data stores, storage of personal data for the web decentralization project Solid
Pod, the basic scheduling unit in Kubernetes
Film and television
Pod (film), an American horror film
Podracer, a type of vehicle from the Star Wars universe
Orthotube or pod, a fictional security device in Spooks
Pod, the growth medium for the replacements in Invasion of the Body Snatchers
Pod, a fictional organic gaming console featured in existenz
Personal Overhaul Device on Snog Marry Avoid?
Music
P.O.D., an American metal band from San Diego, California
Pod (Afro Celt Sound System album) (2004)
Pod (The Breeders album) (1990)
The Pod, a 1991 album by Ween
Pod (amp modeler), a line of guitar amp modelers by Line 6
"POD" (song), a 2006 song by Tenacious D from The Pick of Destiny
"10 Ribs & All/Carrot Pod Pod" or "Pod", a 2015 song on the deluxe edition of Presence by Led Zeppelin
Transportation
Gun pod, a detachable weapons pack
Targeting pod,
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https://en.wikipedia.org/wiki/Stalk
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Stalk or stalking may refer to:
Behaviour
Stalk, the stealthy approach (phase) of a predator towards its prey
Stalking, an act of intrusive behaviour or unwanted attention towards a person
Deer stalking, the pursuit of deer for sport
Biology
Petiole (botany), a leaf stalk
Peduncle (botany), a stalk of an inflorescence or a solitary flower
Pedicel (botany), a stalk of a flower in an inflorescence
Plant stem, one of two main structural axes of a vascular plant
Pituitary stalk, a part of the brain
Other uses
Stalk (sheaf), a mathematical construction
The Stalk, a 1994 science fiction novel by Chris Morris and Janet Morris
See also
Stock (disambiguation)
Stork (disambiguation)
Stalker (disambiguation)
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https://en.wikipedia.org/wiki/1941%20in%20science
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The year 1941 in science and technology involved some significant events, listed below.
Biology
George Wells Beadle and Edward Lawrie Tatum publish "Genetic Control of Biochemical Reactions in Neurospora" which shows that specific genes code for specific proteins.
John William Field develops Field stain to detect malarial parasites.
Chemistry
February 23 – Chemical element 94, plutonium, is first synthesized by Glenn T. Seaborg, Arthur C. Wahl, Joseph W. Kennedy and Emilio Segrè. It is kept secret until after the atomic bombings of Hiroshima and Nagasaki, as it is being developed for the first atomic bombs.
Folic acid is first isolated via extraction from spinach leaves by Herschel K. Mitchell, Esmond E. Snell and Roger J. Williams at the University of Texas at Austin.
The first polyester fibre, polyethylene terephthalate (terylene), is patented by John Rex Whinfield, James T. Dickson and their employer the Calico Printers' Association of Manchester, England.
Computer science
May 12 – German engineer Konrad Zuse presents the Z3, the world's first working programmable, Turing complete, fully automatic computer, to an audience of aviation engineers in Berlin.
John Vincent Atanasoff and Clifford E. Berry develop the Atanasoff–Berry Computer.
History of science
Charles Singer's A Short History of Science to the Nineteenth Century published in the U.K.
Mathematics
Cahit Arf defines the Arf invariant of a nonsingular quadratic form over a field of characteristic 2.
M
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https://en.wikipedia.org/wiki/1936%20in%20science
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The year 1936 in science and technology involved some significant events, listed below.
Chemistry
February 4 – Radium E (bismuth-210) becomes the first radioactive element to be made synthetically.
December 23 – The first nerve agent, Tabun, is discovered (accidentally) by a research team headed by Dr Gerhard Schrader of IG Farben in Germany.
Computer science
May 28 – Alan Turing's paper "On Computable Numbers" is received by the London Mathematical Society for publication, introducing the concept of the theoretical "a[utomatic]-machine" or Turing machine. Its formal publication is on November 12.
Rózsa Péter presents a paper entitled "Über rekursive Funktionen der zweite Stufe" to the International Congress of Mathematicians in Oslo, helping to found the modern field of recursive function theory.
Earth sciences
Inge Lehmann argues that the Earth's molten interior has a solid inner core.
History of science and technology
Economist John Maynard Keynes buys a trunk of Isaac Newton's papers at auction.
Mathematics
March – Alonzo Church's "A Note on the Entscheidungsproblem" is published.
Dutch mathematician Cornelis Simon Meijer introduces the Meijer G-function.
Physiology and medicine
July 4 – First publication recognizing stress as a biological condition.
December 7 – Streptococcous meningitis (a condition previously 99% fatal) is successfully treated for the first time with a sulfonamide.
American researcher Thomas Francis Jr. isolates influenza B virus. Als
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https://en.wikipedia.org/wiki/1935%20in%20science
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The year 1935 in science and technology involved some significant events, listed below.
Astronomy
May 14 – Opening of the Griffith Observatory in Los Angeles, California.
October 3 – Opening of the Hayden Planetarium in New York City.
Chemistry
February 28–March 1 – Working with polyamides to develop a viable new fiber for chemical company DuPont, American chemist Gérard Berchet working under the direction of Wallace Carothers first synthesizes the synthetic polymer nylon at Wilmington, Delaware.
April 13 – Dorothy Hodgkin publishes her first solo paper, on the methodology of X-ray crystallography of insulin.
Vitamin E is first isolated in a pure form by Gladys Anderson Emerson at the University of California, Berkeley.
Eastman Kodak first market Kodachrome subtractive color reversal film as 16 mm movie film. It has been invented by two professional musicians, Leopold Godowsky Jr. and Leopold Mannes.
Ecology
English botanist Arthur Tansley introduces the concept of the ecosystem.
Geology
Charles Richter and Beno Gutenberg develop the Richter magnitude scale for quantifying earthquakes.
History of science and technology
American bacteriologist Hans Zinsser publishes Rats, lice and history: being a study in biography, which... deals with the life history of typhus fever.
Cornish Engines Preservation Committee formed to conserve the Levant Mine beam engine in Cornwall, England.
Mathematics
April 19 – Alonzo Church presents his paper "An unsolvable problem of ele
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https://en.wikipedia.org/wiki/Max%20Planck%20Institute%20for%20Plasma%20Physics
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The Max Planck Institute for Plasma Physics (, IPP) is a physics institute investigating the physical foundations of a fusion power plant.
The IPP is an institute of the Max Planck Society, part of the European Atomic Energy Community, and an associated member of the Helmholtz Association.
The IPP has two sites: Garching near Munich (founded 1960) and Greifswald (founded 1994), both in Germany.
It owns several large devices, namely the experimental tokamak ASDEX Upgrade (in operation since 1991), the experimental stellarator Wendelstein 7-X (in operation since 2016), a tandem accelerator and a high heat flux test facility (GLADIS)
Furthermore it cooperates closely with the ITER, DEMO and JET projects.
The International Helmholtz Graduate School for Plasma Physics partners with the Technical University of Munich (TUM) and the University of Greifswald. Associated partners are the Leibniz Institute for Plasma Science and Technology (INP) in Greifswald and the Leibniz Computational Center (LRZ) in Garching.
External links
References
Fusion power
Plasma physics facilities
Physics research institutes
Plasma Physics
University of Greifswald
Garching bei München
Max Planck
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https://en.wikipedia.org/wiki/Max%20Planck%20Institute%20for%20Astrophysics
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The Max Planck Institute for Astrophysics (MPA) is a research institute located in Garching, just north of Munich, Bavaria, Germany. It is one of many scientific research institutes belonging to the Max Planck Society.
The MPA is widely considered to be one of the leading institutions in the world for theoretical astrophysics research. According to Thomson Reuters, from 1999-2009 the Max Planck Society as a whole published more papers and accumulated more citations in the fields of physics and space science than any other research organization in the world.
History
The Max Planck Society was founded on 26 February 1948. It effectively replaced the Kaiser Wilhelm Society for the Advancement of Science, which was dissolved after World War II. The society is named after Max Planck, one of the founders of quantum theory.
The MPA was founded as the Max Planck Institute for Physics and Astrophysics in 1958 and split into the Max Planck Institute for Astrophysics and the Max Planck Institute for Physics in 1991. In 1995, the numerical relativity group moved to the Max Planck Institute for Gravitational Physics.
Organization
The MPA is one of several Max Planck Institutes that specialize in astronomy and astrophysics. Others are the Max Planck Institute for Extraterrestrial Physics in Garching (located next-door to the MPA), the Max Planck Institute for Astronomy in Heidelberg, the Max Planck Institute for Radio Astronomy in Bonn, the Max Planck Institute for Solar System Researc
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https://en.wikipedia.org/wiki/Max%20Planck%20Institute%20for%20Extraterrestrial%20Physics
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The Max Planck Institute for Extraterrestrial Physics is part of the Max Planck Society, located in Garching, near Munich, Germany.
In 1991 the Max Planck Institute for Physics and Astrophysics split up into the Max Planck Institute for Extraterrestrial Physics, the Max Planck Institute for Physics and the Max Planck Institute for Astrophysics. The Max Planck Institute for Extraterrestrial Physics was founded as sub-institute in 1963. The
scientific activities of the institute are mostly devoted to astrophysics with telescopes orbiting in space. A large amount of the resources
are spent for studying black holes in the galaxy and in the remote universe.
History
The Max-Planck-Institute for extraterrestrial physics (MPE) was preceded by the department for extraterrestrial physics in the Max-Planck-Institute for physics and astrophysics. This department was established by Professor Reimar Lüst on October 23, 1961. A Max-Planck Senate resolution transformed this department into a sub-institute of the Max-Planck-Institute for Physics and Astrophysics on May 15, 1963. Professor Lüst was appointed director of the institute. Another Senate resolution on March 8, 1991, finally established MPE as an autonomous institute within the Max-Planck-Gesellschaft. It is dedicated to the experimental and theoretical exploration of the space outside of earth as well as astrophysical phenomena.
Timeline
Major events in the history of the institute include:
1963 Foundation as a sub-institute
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https://en.wikipedia.org/wiki/Yousef%20Alavi
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Yousef Alavi (March 19, 1928 – May 21, 2013) was an Iranian born American mathematician who specialized in combinatorics and graph theory. He received his PhD from Michigan State University in 1958. He was a professor of mathematics at Western Michigan University from 1958 until his retirement in 1996; he chaired the department from 1989 to 1992.
In 1987 he received the first Distinguished Service Award of the Michigan Section of the Mathematical Association of America due to his 30 years of service to the MAA; at that time, the Michigan House and Senate issued a special resolution honoring him.
References
20th-century American mathematicians
Combinatorialists
2013 deaths
Michigan State University alumni
Western Michigan University faculty
1928 births
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https://en.wikipedia.org/wiki/B%C3%A9la%20Bollob%C3%A1s
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Béla Bollobás FRS (born 3 August 1943) is a Hungarian-born British mathematician who has worked in various areas of mathematics, including functional analysis, combinatorics, graph theory, and percolation. He was strongly influenced by Paul Erdős since the age of 14.
Early life and education
As a student, he took part in the first three International Mathematical Olympiads, winning two gold medals. Paul Erdős invited Bollobás to lunch after hearing about his victories, and they kept in touch afterward. Bollobás' first publication was a joint publication with Erdős on extremal problems in graph theory, written when he was in high school in 1962.
With Erdős's recommendation to Harold Davenport and a long struggle for permission from the Hungarian authorities, Bollobás was able to spend an undergraduate year in Cambridge, England. However, the authorities denied his request to return to Cambridge for doctoral study. A similar scholarship offer from Paris was also quashed. He wrote his first doctorate in discrete geometry under the supervision of László Fejes Tóth and Paul Erdős in Budapest University, 1967, after which he spent a year in Moscow with Israïl Moiseevich Gelfand. After spending a year at Christ Church, Oxford, where Michael Atiyah held the Savilian Chair of Geometry, he vowed never to return to Hungary due to his disillusion with the 1956 Soviet intervention. He then went to Trinity College, Cambridge, where in 1972 he received a second PhD in functional analysis,
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https://en.wikipedia.org/wiki/Don%20Lind
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Don Leslie Lind (May 18, 1930 – August 30, 2022) was an American scientist, naval officer, aviator, and NASA astronaut. He graduated from the University of Utah with an undergraduate degree in physics in 1953. Following his military service obligation, he earned a PhD in high-energy nuclear physics from the University of California, Berkeley in 1964.
Lind was a Naval Aviator and attained the rank of commander in the United States Naval Reserve. After completing his doctorate, Lind worked at NASA's Goddard Research Center from 1964 to 1966. Selected with Astronaut Group 5 in 1966, he helped to develop the Apollo 11 EVA activities, and served as CAPCOM for the Apollo 11 and Apollo 12 missions. Lind was then assigned as backup pilot for Skylab 3 and Skylab 4 and would have flown on Skylab Rescue.
Lind was the payload commander on his only flight, STS-51-B, launched April 29, 1985. He designed an experiment to capture the Earth's aurora. The payload experiments consisted primarily of microgravity research and atmospheric measurement. The Orbiter Challenger completed 110 orbits before landing at Edwards Air Force Base, California.
Biography
Early life and education
Lind was born May 18, 1930, and raised in Midvale, Utah, with his two sisters, Charlene and Kathleen. He attended Midvale Elementary School and graduated from Jordan High School in 1948. He was an Eagle Scout with the Boy Scouts of America, its highest rank. He received a Bachelor of Science degree with high honors
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https://en.wikipedia.org/wiki/Ralph%20Faudree
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Ralph Jasper Faudree (August 23, 1939 – January 13, 2015) was a mathematician, a professor of mathematics and the former provost of the University of Memphis.
Faudree was born in Durant, Oklahoma. He did his undergraduate studies at Oklahoma Baptist University, graduating in 1961, and received his Ph.D. in 1964 from Purdue University under the supervision of Eugene Schenkman (1922–1977). Faudree was an instructor at the University of California, Berkeley and an assistant professor at the University of Illinois before joining the Memphis State University faculty as an associate professor in 1971. Memphis State became renamed as the University of Memphis in 1994, and Faudree was appointed as provost in 2001.
Faudree specialized in combinatorics, and specifically in graph theory and Ramsey theory. He published more than 200 mathematical papers on these topics together with such notable mathematicians as Béla Bollobás, Stefan Burr, Paul Erdős, Ron Gould, András Gyárfás, Brendan McKay, Cecil Rousseau, Richard Schelp, Miklós Simonovits, Joel Spencer, and Vera Sós. He was the 2005 recipient of the Euler Medal for his contributions to combinatorics. His Erdős number was 1: he cowrote 50 joint papers with Paul Erdős beginning in 1976 and was among the three mathematicians who most frequently co-authored with Erdős.
Selected publications
References
External links
Archived version of the professional webpage
1939 births
2015 deaths
20th-century American mathematicians
21st-centur
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https://en.wikipedia.org/wiki/G.%20David%20Low
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George David Low (February 19, 1956 – March 15, 2008) was an American aerospace executive and a NASA astronaut. With undergraduate degrees in physics and mechanical engineering and a master's degree in aeronautics and astronautics, he worked in the Jet Propulsion Laboratory (JPL) at the California Institute of Technology in the early 80's, before being picked as an astronaut candidate by NASA in 1984. In addition to holding some technical assignments, he logged more than 700 hours in space (including stints on the Columbia, the Atlantis, and the Endeavour Space Shuttles), before he left NASA in 1996 to pursue a career in the private sector. He was the son of George M. Low, the manager of the Apollo Spacecraft Program Office, and later, the 14th president of Rensselaer Polytechnic Institute.
Personal life
Low was born February 19, 1956, in Cleveland, Ohio to George and Mary Ruth Low (nee McNamera), and was active in the Boy Scouts of America where he achieved its second highest rank, Life Scout. He was married to the former JoAnn Andochick of Weirton, West Virginia. They had three children Maggie, Chris, and Abigail. He enjoyed tennis, lacrosse, scuba diving, running, and spending time with his family. His father in 1968 proposed that Apollo 8 fly around the moon.
Low died of colon cancer on March 15, 2008, at Reston Hospital Center in Virginia.
Education
Low graduated from Langley High School, McLean, Virginia, in 1974; received a Bachelor of Science degree in Physics-E
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https://en.wikipedia.org/wiki/Jerome%20F.%20Lederer
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Jerome F. Lederer (September 26, 1902 – February 6, 2004) was an American aviation-safety pioneer, known as "Mr. Aviation Safety."
He was born in New York City. He received a BSC in mechanical engineering with aeronautical options in 1924 and an M.E. in 1925 from New York University. In 1926, he was hired by the United States Postal Service to oversee its plane maintenance. Lederer helped reduce pilot fatality by devising film crash tests and redesigning the exhaust stacks and other systems. From 1929 to 1940, he served as chief engineer for aviation insurance underwriters. In 1940, he accepted an appointment as director of the Civil Aeronautics Board's Safety Bureau. He resigned in 1942 to become director of the Airlines War Training Institute. He trained 10,000 airmen and 35,000 mechanics for the Air Transport Command, and was a safety consultant to the 2nd Air Force.
In 1947, he organized the Flight Safety Foundation and was its director until 1967. The Foundation provides global exchange of information on aircraft accident prevention. In 1967, following the deaths of three astronauts at the Kennedy Space Center, NASA appointed him director of the Office of Manned Space Flight Safety for the Apollo Program. In 1970, he became director of safety for all of NASA.
In 1987, Lederer was the recipient of the Tony Jannus Award for his distinguished contributions to commercial aviation. He died of congestive heart failure in Laguna Hills, California, at the age of 101.
Lederer
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https://en.wikipedia.org/wiki/Heterogeneous%20Element%20Processor
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The Heterogeneous Element Processor (HEP) was introduced by Denelcor, Inc. in 1982. The HEP's architect was Burton Smith. The machine was designed to solve fluid dynamics problems for the Ballistic Research Laboratory. A HEP system, as the name implies, was pieced together from many heterogeneous components -- processors, data memory modules, and I/O modules. The components were connected via a switched network.
A single processor, called a PEM, in a HEP system (up to sixteen PEMs could be connected) was rather unconventional; via a "program status word (PSW) queue," up to fifty processes could be maintained in hardware at once. The largest system ever delivered had 4 PEMs. The eight-stage instruction pipeline allowed instructions from eight different processes to proceed at once. In fact, only one instruction from a given process was allowed to be present in the pipeline at any point in time. Therefore, the full processor throughput of 10 MIPS could only be achieved when eight or more processes were active; no single process could achieve throughput greater than 1.25 MIPS. This type of multithreading processing classifies the HEP as a barrel processor. The hardware implementation of the HEP PEM was emitter-coupled logic.
Processes were classified as either user-level or supervisor-level. User-level processes could create supervisor-level processes, which were used to manage user-level processes and perform I/O. Processes of the same class were required to be groupe
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https://en.wikipedia.org/wiki/Phenylpropanolamine
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Phenylpropanolamine (PPA) is a sympathomimetic agent which is used as a decongestant and appetite suppressant. It was commonly used in prescription and over-the-counter cough and cold preparations. In veterinary medicine, it is used to control urinary incontinence in dogs.
Chemistry
PPA is also known as β-hydroxyamphetamine, and is a member of the phenethylamine and amphetamine chemical classes. It is closely related to the cathinones (β-ketoamphetamines). The compound exists as four stereoisomers, which include d- and l-norephedrine and d- and l-norpseudoephedrine. d-Norpseudoephedrine is also known as cathine, and is found naturally in Catha edulis (khat). Pharmaceutical drug preparations of PPA have varied in their stereoisomer composition in different countries, which may explain differences in misuse and side effect profiles. Analogues of PPA include ephedrine, pseudoephedrine, amphetamine, methamphetamine, and cathinone.
PPA, structurally, is in the substituted phenethylamine class, consisting of a cyclic benzene or phenyl group, a two carbon ethyl moiety, and a terminal nitrogen, hence the name phen-ethyl-amine. The methyl group on the alpha carbon (the first carbon before the nitrogen group) also makes this compound a member of the substituted amphetamine class. Ephedrine is the N-methyl analogue of PPA.
Exogenous compounds in this family are degraded too rapidly by monoamine oxidase to be active at all but the highest doses. However, the addition of the α-methyl
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https://en.wikipedia.org/wiki/Steganalysis
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Steganalysis is the study of detecting messages hidden using steganography; this is analogous to cryptanalysis applied to cryptography.
Overview
The goal of steganalysis is to identify suspected packages, determine whether or not they have a payload encoded into them, and, if possible, recover that payload.
Unlike cryptanalysis, in which intercepted data contains a message (though that message is encrypted), steganalysis generally starts with a pile of suspect data files, but little information about which of the files, if any, contain a payload. The steganalyst is usually something of a forensic statistician, and must start by reducing this set of data files (which is often quite large; in many cases, it may be the entire set of files on a computer) to the subset most likely to have been altered.
Basic techniques
The problem is generally handled with statistical analysis. A set of unmodified files of the same type, and ideally from the same source (for example, the same model of digital camera, or if possible, the same digital camera; digital audio from a CD MP3 files have been "ripped" from; etc.) as the set being inspected, are analyzed for various statistics. Some of these are as simple as spectrum analysis, but since most image and audio files these days are compressed with lossy compression algorithms, such as JPEG and MP3, they also attempt to look for inconsistencies in the way this data has been compressed. For example, a common artifact in JPEG compressio
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https://en.wikipedia.org/wiki/James%20H.%20Ellis
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James Henry Ellis (25 September 1924 – 25 November 1997) was a British engineer and cryptographer. In 1970, while working at the Government Communications Headquarters (GCHQ) in Cheltenham, he conceived of the possibility of "non-secret encryption", more commonly termed public-key cryptography.
Early life, education and career
Ellis was born in Britain, although he was conceived in Australia, and grew up in Britain. He almost died at birth, and it was thought that he might be learning disabled. He became an orphan who lived with his grandparents in London's East End. He showed a gift for mathematics and physics at a grammar school in Leyton, and gained a degree in physics. He then worked at the Post Office Research Station at Dollis Hill. In 1952, Ellis joined the Government Communications Headquarters (GCHQ) in Eastcote, west London. In 1965, he moved to Cheltenham to join the newly formed Communications-Electronics Security Group (CESG), an arm of GCHQ. In 1949, Ellis married Brenda, an artist and designer, and they had four children but she never knew anything about his work.
Invention of non-secret encryption
Ellis first proposed his scheme for "non-secret encryption" in 1970, in a (then) secret GCHQ internal report "The Possibility of Secure Non-Secret Digital Encryption".
Ellis said that the idea first occurred to him after reading a paper from World War II by someone at Bell Labs describing the scheme named Project C43, a way to protect voice communications by the r
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https://en.wikipedia.org/wiki/KHAZAD
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In cryptography, KHAZAD is a block cipher designed by Paulo S. L. M. Barreto together with Vincent Rijmen, one of the designers of the Advanced Encryption Standard (Rijndael). KHAZAD is named after Khazad-dûm, the fictional dwarven realm in the writings of J. R. R. Tolkien (see also Khazad). KHAZAD was presented at the first NESSIE workshop in 2000, and, after some small changes, was selected as a finalist in the project.
KHAZAD has an eight-round substitution–permutation network structure similar to that of SHARK, a forerunner to Rijndael. The design is classed as a "legacy-level" algorithm, with a 64-bit block size (in common with older ciphers such as DES and IDEA) and a 128-bit key. KHAZAD makes heavy use of involutions as subcomponents; this minimises the difference between the algorithms for encryption and decryption.
The authors have stated that, "KHAZAD is not (and will never be) patented. It may be used free of charge for any purpose."
Frédéric Muller has discovered an attack which can break five of KHAZAD's eight rounds. No attacks better than this are known as of August 2009.
References
External links
Block ciphers
Free ciphers
Things named after Tolkien works
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https://en.wikipedia.org/wiki/Andrey%20Tikhonov%20%28mathematician%29
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Andrey Nikolayevich Tikhonov (; 17 October 1906 – 7 October 1993) was a leading Soviet Russian mathematician and geophysicist known for important contributions to topology, functional analysis, mathematical physics, and ill-posed problems. He was also one of the inventors of the magnetotellurics method in geophysics. Other transliterations of his surname include "Tychonoff", "Tychonov", "Tihonov", "Tichonov."
Biography
Born in Gzhatsk, he studied at the Moscow State University where he received a Ph.D. in 1927 under the direction of Pavel Sergeevich Alexandrov. In 1933 he was appointed as a professor at Moscow State University. He became a corresponding member of the USSR Academy of Sciences on 29 January 1939 and a full member of the USSR Academy of Sciences on 1 July 1966.
Research work
Tikhonov worked in a number of different fields in mathematics. He made important contributions to topology, functional analysis, mathematical physics, and certain classes of ill-posed problems. Tikhonov regularization, one of the most widely used methods to solve ill-posed inverse problems, is named in his honor. He is best known for his work on topology, including the metrization theorem he proved in 1926, and the Tychonoff's theorem, which states that every product of arbitrarily many compact topological spaces is again compact. In his honor, completely regular topological spaces are also named Tychonoff spaces.
In mathematical physics, he proved the fundamental uniqueness theorems
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https://en.wikipedia.org/wiki/Nicolaus%20Tideman
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Thorwald Nicolaus Tideman (, not ; born August 11, 1943, in Chicago, Illinois) is a Georgist economist and professor at Virginia Tech. He received his Bachelor of Arts in economics and mathematics from Reed College in 1965 and his PhD in economics from the University of Chicago in 1969. Tideman was an Assistant Professor of Economics at Harvard University from 1969 to 1973, during which time from 1970 to 1971 he was a Senior Staff Economist for the President's Council of Economic Advisors. Since 1973, he has been at Virginia Tech, with various visiting positions at Harvard Kennedy School (1979-1980), University of Buckingham (1985-1986), and the American Institute for Economic Research (1999-2000).
Research
Tideman's academic interests include taxation of land, voting theory, and political philosophy.
Ranked Pairs
In 1987, he devised the voting system called "ranked pairs" (or the "Tideman method" or simply "RP"), which is a type of Condorcet method. It selects a single winner using votes that express a preference ranking. Ranked pairs can also be used to create a sorted list of winners.
Other research
In 2000, Tideman developed the CPO-STV proportional voting method. Tideman also devised the independence of clones criterion which both of his methods satisfy. He is an associate of the Earth Rights Institute. His book Collective Decisions and Voting: The Potential for Public Choice was published by Ashgate Publishing in November 2006.
References
External links
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https://en.wikipedia.org/wiki/IHP
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IHP may refer to:
Indicated horsepower
Innovations for High Performance Microelectronics, a German institute and part of the Gottfried Wilhelm Leibniz Scientific Community
Institut Henri Poincaré, a mathematics research institute in Paris, France
Integrated Humanities Program
International Hydrological Programme
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https://en.wikipedia.org/wiki/PKCS
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In cryptography, PKCS (Public Key Cryptography Standards) are a group of public key cryptography standards devised and published by RSA Security LLC, starting in the early 1990s. The company published the standards to promote the use of the cryptography techniques to which they had patents, such as the RSA algorithm, the Schnorr signature algorithm and several others. Though not industry standards (because the company retained control over them), some of the standards have begun to move into the "standards track" processes of relevant standards organizations in recent years, such as the IETF and the PKIX working group.
See also
Cryptographic Message Syntax
References
General
External links
About PKCS (appendix G from RFC 3447)
OASIS PKCS 11 TC (technical committee home page)
Cryptography standards
Public-key cryptography
Standards of the United States
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https://en.wikipedia.org/wiki/James%20Sumner
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James Sumner may refer to:
James Sumner (Medal of Honor) (1840–1912), United States Army soldier and a recipient of the Medal of Honor
James Sumner (baseball) (1851–1881), American baseball umpire
James B. Sumner (1887–1955), American chemist who shared the Nobel Prize in Chemistry
James Edward (Red) Sumner, Jr. (born 1948), stellar occultation astronomer after whom asteroid 36983 Sumner is named
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https://en.wikipedia.org/wiki/IPM
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IPM may refer to:
Organizations
Independence Party of Minnesota, a political party in Minnesota, United States
Institute for Studies in Theoretical Physics and Mathematics, a research institute in Tehran, Iran
Institute of Personnel Management, now the Chartered Institute of Personnel and Development
International Partnership for Microbicides, a non-profit partnership to find a safe and effective microbicide
Science and technology
Imipenem, an antibiotic belonging to the carbapenem class of drugs
Inch per minute, a measure of speed or velocity
Independent-particle model, of nuclear structure (structure of the atomic nucleus)
Integrated power module, a fuse box in an automobile
Interior permanent magnet, the type of motor used in a hybrid electric vehicle
Interior-point method in mathematical programming (optimization)
International prototype metre, a former standard to define the length of a metre
Interplanetary medium, the material which fills the solar system
Intranodal palisaded myofibroblastoma, a rare primary lymph node tumour
Isopropyl myristate, a chemical used in cosmetics and perfumes
InfoPrint Manager, IBM Advanced Function Presentation software
IPM (software), Interactive Policy Making, an online opinion poll management system
Intelligent Power Module, a type of high-performance module designed to drive IGBT devices
Other uses
iPM, a spin-off program of BBC Radio 4's PM
IPM Zmaj, a Serbian company that produces small agricultural machines
Inf
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https://en.wikipedia.org/wiki/Ozone%E2%80%93oxygen%20cycle
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The ozone–oxygen cycle is the process by which ozone is continually regenerated in Earth's stratosphere, converting ultraviolet radiation (UV) into heat. In 1930 Sydney Chapman resolved the chemistry involved. The process is commonly called the Chapman cycle by atmospheric scientists.
Most of the ozone production occurs in the tropical upper stratosphere and mesosphere. The total mass of ozone produced per day over the globe is about 400 million metric tons. The global mass of ozone is relatively constant at about 3 billion metric tons, meaning the Sun produces about 12% of the ozone layer each day.
Photochemistry
The Chapman cycle describes the main reactions that naturally determine, to first approximation, the concentration of ozone in the stratosphere. It includes four processes - and a fifth, less important one - all involving oxygen atoms and molecules, and UV radiation:
Creation
An oxygen molecule is split (photolyzed) by higher frequency UV light (top end of UV-B, UV-C and above) into two oxygen atoms (see figure):
1. oxygen photodissociation: O2 + ℎν(<242 nm) → 2 O
Each oxygen atom may then combine with an oxygen molecule to form an ozone molecule:
2. ozone creation: O + O2 + A → O3 + A
where A denotes an additional molecule or atom, such as N2 or O2, required to maintain the conservation of energy and momentum in the reaction. Any excess energy is produced as kinetic energy.
The ozone–oxygen cycle
The ozone molecules formed by the reaction (above) absorb radiat
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https://en.wikipedia.org/wiki/Five-prime%20cap
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In molecular biology, the five-prime cap (5′ cap) is a specially altered nucleotide on the 5′ end of some primary transcripts such as precursor messenger RNA. This process, known as mRNA capping, is highly regulated and vital in the creation of stable and mature messenger RNA able to undergo translation during protein synthesis. Mitochondrial mRNA and chloroplastic mRNA are not capped.
Structure
In eukaryotes, the 5′ cap (cap-0), found on the 5′ end of an mRNA molecule, consists of a guanine nucleotide connected to mRNA via an unusual 5′ to 5′ triphosphate linkage. This guanosine is methylated on the 7 position directly after capping in vivo by a methyltransferase. It is referred to as a 7-methylguanylate cap, abbreviated m7G.
In multicellular eukaryotes and some viruses, further modifications exist, including the methylation of the 2′ hydroxy-groups of the first 2 ribose sugars of the 5′ end of the mRNA. cap-1 has a methylated 2′-hydroxy group on the first ribose sugar, while cap-2 has methylated 2′-hydroxy groups on the first two ribose sugars, shown on the right. The 5′ cap is chemically similar to the 3′ end of an RNA molecule (the 5′ carbon of the cap ribose is bonded, and the 3′ unbonded). This provides significant resistance to 5′ exonucleases.
Small nuclear RNAs contain unique 5′-caps. Sm-class snRNAs are found with 5′-trimethylguanosine caps, while Lsm-class snRNAs are found with 5′-monomethylphosphate caps.
In bacteria, and potentially also in higher organism
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https://en.wikipedia.org/wiki/Armin%20Otto%20Leuschner
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Armin Otto Leuschner (January 16, 1868 – April 22, 1953) was an American astronomer and educator.
Biography
Leuschner was born on January 16, 1868, in Detroit, Michigan, but raised in Germany. He returned to the United States for university studies, graduating from the University of Michigan in 1888 with a degree in mathematics. Leuschner then became the first graduate student at Lick Observatory, but due to conflicts with his advisor, Lick director Edward S. Holden, he left Lick before finishing his Ph.D. Leuschner subsequently returned to Germany and attended the University of Berlin, where in 1897 he earned his doctorate with a highly praised thesis on the orbits of comets.
He returned to California as an associate professor in astronomy at University of California, Berkeley, where he remained for over half a century. He founded an observatory there for student instruction, later renamed in his honor Leuschner Observatory. Together with Lick director James E. Keeler, Leuschner shaped the combined graduate program at Berkeley and Lick into one of the nation's foremost centers of astronomical education. Leuschner's own research continued to focus on the orbits of asteroids and comets; this subject required tremendous amounts of detailed computation, which made the work well-suited to be shared with a long series of students, many of whom went on to successful astronomical careers of their own. More than sixty students received their doctorate under Leuschner's guidance.
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https://en.wikipedia.org/wiki/Vincenzo%20Cerulli
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Vincenzo Cerulli (20 April 1859 – 30 May 1927) was an Italian astronomer and founder of the Collurania-Teramo Observatory in Teramo, central Italy, where he was born.
He earned a degree in physics from the Sapienza University of Rome in 1881, and continued his studies at the University of Berlin. Cerulli compiled a star catalog with Elia Millosevich. He was the astronomer at the Pontifical Gregorian University.
In 1890, he founded his observatory, which he named "Collurania", equipping it with a 40 cm Cooke refractor, which he had purchased for £2000 (£210,652 at the 2020 equivalent) from the son of British Astronomer, James Wigglesworth (born, Wibsey 1815) and which had been situated in Scarborough, before being dismantled and moved to Teramo. He also observed Mars and developed the theory that the Martian canals were not real but an optical illusion, a theory that was later confirmed.
He discovered one asteroid, 704 Interamnia, which is named after the Latin name for Teramo, and is notable for its relatively large diameter of approximately 350 km, which makes it the fifth largest body in the traditional asteroid belt.
Cerulli was a corresponding member of the Lincei Academy, Rome; the Pontaniana Academy, Naples; and the Academy of Sciences, Turin. He contributed the article on Lorenzo Respighi to the Catholic Encyclopedia.
Cerulli died at Merate, Province of Lecco, in 1927. The 130-kilometer Martian crater Cerulli, as well as the asteroids 366 Vincentina and 31028 Cer
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https://en.wikipedia.org/wiki/Extinction%20%28disambiguation%29
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Extinction, in biology and palaeontology, is the end of a species or other taxon.
Extinction may also refer to:
Science
Mass extinction, or extinction event, a widespread and rapid decrease in the amount of life on earth
Human extinction (end of the human species)
Language extinction, or language death
Extinction (another word for attenuation), in physical sciences
Extinction coefficient (another term for mass attenuation coefficient), in physical sciences
Extinction (astronomy)
Extinction (optical mineralogy), when cross-polarized light dims, as viewed through a thin section of a mineral in a petrographic microscope
Bird's eye extinction, in optical mineralogy
Undulose extinction, a geological term
Ewald–Oseen extinction theorem in optics, when light changes media
Extinction (psychology), when a conditioned response is reduced or lost
Extinction (neurology), a neurological disorder that impairs the ability to perceive multiple stimuli of the same type simultaneously
Film and television
"Extinction" (Star Trek: Enterprise), television episode
"Extinction" (Smallville episode), television episode
Resident Evil: Extinction, a 2007 film starring Milla Jovovich
Transformers: Age of Extinction, a 2014 Transformers film
Extinction (2015 film), a 2015 film starring Matthew Fox
Extinction (2018 film), a 2018 science fiction thriller film
Literature
Extinction (Forgotten Realms novel), a fantasy novel by Lisa Smedman
Extinction (Bernhard novel), a 1986 novel by Thom
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https://en.wikipedia.org/wiki/Semicircle
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In mathematics (and more specifically geometry), a semicircle is a one-dimensional locus of points that forms half of a circle. It is a circular arc that measures 180° (equivalently, radians, or a half-turn). It has only one line of symmetry (reflection symmetry).
In non-technical usage, the term "semicircle" is sometimes used to refer to either a closed curve that also includes the diameter segment from one end of the arc to the other or to the half-disk, which is a two-dimensional geometric region that further includes all the interior points.
By Thales' theorem, any triangle inscribed in a semicircle with a vertex at each of the endpoints of the semicircle and the third vertex elsewhere on the semicircle is a right triangle, with a right angle at the third vertex.
All lines intersecting the semicircle perpendicularly are concurrent at the center of the circle containing the given semicircle.
Uses
A semicircle can be used to construct the arithmetic and geometric means of two lengths using straight-edge and compass. For a semicircle with a diameter of a + b, the length of its radius is the arithmetic mean of a and b (since the radius is half of the diameter).
The geometric mean can be found by dividing the diameter into two segments of lengths a and b, and then connecting their common endpoint to the semicircle with a segment perpendicular to the diameter. The length of the resulting segment is the geometric mean. This can be proven by applying the Pythagorean theo
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https://en.wikipedia.org/wiki/Radomir%20Naumov
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Radomir Naumov (; 12 May 1946 – 22 May 2015) was a Serbian politician and engineer. He served as the Minister of Religion from 2007 to 2008, and as the Minister of Mining and Energy from 2004 to 2007.
Naumov graduated from the University of Belgrade Faculty of Electrical Engineering. He worked at the Nikola Tesla Electrical Engineering Institute for many years. Naumov was president of Belgrade office of the Democratic Party of Serbia. He was married with two children.
References
External links
1946 births
2015 deaths
People from Čoka
University of Belgrade School of Electrical Engineering alumni
Democratic Party of Serbia politicians
Government ministers of Serbia
Politicians of Vojvodina
Yugoslav engineers
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https://en.wikipedia.org/wiki/Power%20engineering
|
Power engineering, also called power systems engineering, is a subfield of electrical engineering that deals with the generation, transmission, distribution, and utilization of electric power, and the electrical apparatus connected to such systems. Although much of the field is concerned with the problems of three-phase AC power – the standard for large-scale power transmission and distribution across the modern world – a significant fraction of the field is concerned with the conversion between AC and DC power and the development of specialized power systems such as those used in aircraft or for electric railway networks. Power engineering draws the majority of its theoretical base from electrical engineering and mechanical engineering.
History
Pioneering years
Electricity became a subject of scientific interest in the late 17th century. Over the next two centuries a number of important discoveries were made including the incandescent light bulb and the voltaic pile. Probably the greatest discovery with respect to power engineering came from Michael Faraday who in 1831 discovered that a change in magnetic flux induces an electromotive force in a loop of wire—a principle known as electromagnetic induction that helps explain how generators and transformers work.
In 1881 two electricians built the world's first power station at Godalming in England. The station employed two waterwheels to produce an alternating current that was used to supply seven Siemens arc lamps at 250
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https://en.wikipedia.org/wiki/Electric%20power%20conversion
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In all fields of electrical engineering, power conversion is the process of converting electric energy from one form to another. A power converter is an electrical or electro-mechanical device for converting electrical energy. A power converter can convert alternating current (AC) into direct current (DC) and vice versa; change the voltage or frequency of the current or do some combination of these. The power converter can be as simple as a transformer or it can be a far more complex system, such as a resonant converter. The term can also refer to a class of electrical machinery that is used to convert one frequency of alternating current into another. Power conversion systems often incorporate redundancy and voltage regulation.
Power converters are classified based on the type of power conversion they do. One way of classifying power conversion systems is according to whether the input and output are alternating current or direct current. Finally, the task of all power converters is to "process and control the flow of electrical energy by supplying voltages and currents in a form that is optimally suited for user loads".
DC power conversion
DC to DC
The following devices can convert DC to DC:
Linear regulator
Voltage regulator
Motor–generator
Rotary converter
Switched-mode power supply
DC to AC
The following devices can convert DC to AC:
Power inverter
Motor–generator
Rotary converter
Switched-mode power supply
Chopper (electronics)
AC power conversion
AC to DC
The fo
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https://en.wikipedia.org/wiki/International%20Muon%20Ionization%20Cooling%20Experiment
|
The International Muon Ionization Cooling Experiment (or MICE) is a high energy physics experiment at the Rutherford Appleton Laboratory. The experiment is a recognized CERN experiment (RE11).
MICE is designed to demonstrate ionization cooling of muons. This is a process whereby the emittance of a beam is reduced in order to reduce the beam size, so that more muons can be accelerated in smaller aperture accelerators and with fewer focussing magnets. This might enable the construction of high intensity muon accelerators, for example for use as a Neutrino Factory or Muon Collider.
MICE will reduce the transverse emittance of a muon beam over a single 7 m cooling cell and measure that reduction. The original MICE design was based on a scheme outlined in Feasibility Study II., it was revised significantly in 2014. Pions will be produced from a target in the ISIS neutron source and transported along a beamline where most will decay to muons before entering MICE. Cooling is tested with lithium hydride (LiH) crystals or liquid hydrogen (LH2) cells, magnets are used to focus and analyze the muon beam. MICE will measure cooling performance over a range of beam momenta between about 150 and 250 MeV/c.
Beamline
The MICE muon beamline provides a low intensity muon beam for MICE. Pions will be transported from a target dipping into the fringe of the ISIS proton beam, through a pion decay channel, into a muon transport line and then into MICE. For efficient use of muons it is desirabl
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https://en.wikipedia.org/wiki/Superpartner
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In particle physics, a superpartner (also sparticle) is a class of hypothetical elementary particles predicted by supersymmetry, which, among other applications, is one of the well-studied ways to extend the standard model of high-energy physics.
When considering extensions of the Standard Model, the s- prefix from sparticle is used to form names of superpartners of the Standard Model fermions (sfermions), e.g. the stop squark. The superpartners of Standard Model bosons have an -ino (bosinos) appended to their name, e.g. gluino, the set of all gauge superpartners are called the gauginos.
Theoretical predictions
According to the supersymmetry theory, each fermion should have a partner boson, the fermion's superpartner, and each boson should have a partner fermion. Exact unbroken supersymmetry would predict that a particle and its superpartners would have the same mass. No superpartners of the Standard Model particles have yet been found. This may indicate that supersymmetry is incorrect, or it may also be the result of the fact that supersymmetry is not an exact, unbroken symmetry of nature. If superpartners are found, their masses would indicate the scale at which supersymmetry is broken.
For particles that are real scalars (such as an axion), there is a fermion superpartner as well as a second, real scalar field. For axions, these particles are often referred to as axinos and saxions.
In extended supersymmetry there may be more than one superparticle for a given partic
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https://en.wikipedia.org/wiki/Absorber
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In high energy physics experiments, an absorber is a block of material used to absorb some of the energy of an incident particle in an experiment. Absorbers can be made of a variety of materials, depending on the purpose; lead, tungsten and liquid hydrogen are common choices. Most absorbers are used as part of a particle detector; particle accelerators use absorbers to reduce the radiation damage on accelerator components.
Other uses of the same word
Absorbers are used in ionization cooling, as in the International Muon Ionization Cooling Experiment.
In solar power, a high degree of efficiency is achieved by using black absorbers which reflect off much less of the incoming energy.
In sunscreen formulations, ingredients which absorb UVA/UVB rays, such as avobenzone and octyl methoxycinnamate, are known as absorbers. They are contrasted with physical "blockers" of UV radiation such as titanium dioxide and zinc oxide.
References
Particle detectors
Accelerator physics
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https://en.wikipedia.org/wiki/Coset%20enumeration
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In mathematics, coset enumeration is the problem of counting the cosets of a subgroup H of a group G given in terms of a presentation. As a by-product, one obtains a permutation representation for G on the cosets of H. If H has a known finite order, coset enumeration gives the order of G as well.
For small groups it is sometimes possible to perform a coset enumeration by hand. However, for large groups it is time-consuming and error-prone, so it is usually carried out by computer. Coset enumeration is usually considered to be one of the fundamental problems in computational group theory.
The original algorithm for coset enumeration was invented by John Arthur Todd and H. S. M. Coxeter. Various improvements to the original Todd–Coxeter algorithm have been suggested, notably the classical strategies of V. Felsch and HLT (Haselgrove, Leech and Trotter). A practical implementation of these strategies with refinements is available at the ACE website. The Knuth–Bendix algorithm also can perform coset enumeration, and unlike the Todd–Coxeter algorithm, it can sometimes solve the word problem for infinite groups.
The main practical difficulties in producing a coset enumerator are that it is difficult or impossible to predict how much memory or time will be needed to complete the process. If a group is finite, then its coset enumeration must terminate eventually, although it may take arbitrarily long and use an arbitrary amount of memory, even if the group is trivial. Depending on
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https://en.wikipedia.org/wiki/Computational%20group%20theory
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In mathematics, computational group theory is the study of
groups by means of computers. It is concerned
with designing and analysing algorithms and
data structures to compute information about groups. The subject
has attracted interest because for many interesting groups
(including most of the sporadic groups) it is impractical
to perform calculations by hand.
Important algorithms in computational group theory include:
the Schreier–Sims algorithm for finding the order of a permutation group
the Todd–Coxeter algorithm and Knuth–Bendix algorithm for coset enumeration
the product-replacement algorithm for finding random elements of a group
Two important computer algebra systems (CAS) used for group theory are
GAP and Magma. Historically, other systems such as CAS (for character theory) and Cayley (a predecessor of Magma) were important.
Some achievements of the field include:
complete enumeration of all finite groups of order less than 2000
computation of representations for all the sporadic groups
See also
Black box group
References
A survey of the subject by Ákos Seress from Ohio State University, expanded from an article that appeared in the Notices of the American Mathematical Society is available online. There is also a survey by Charles Sims from Rutgers University and an older survey by Joachim Neubüser from RWTH Aachen.
There are three books covering various parts of the subject:
Derek F. Holt, Bettina Eick, Eamonn A. O'Brien, "Handbook of computational g
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https://en.wikipedia.org/wiki/Sensitive%20compartmented%20information
|
Sensitive compartmented information (SCI) is a type of United States classified information concerning or derived from sensitive intelligence sources, methods, or analytical processes. All SCI must be handled within formal access control systems established by the Director of National Intelligence.
SCI is not a classification; SCI clearance has sometimes been called "above Top Secret", but information at any classification level may exist within an SCI control system. When "decompartmentalized", this information is treated the same as collateral information at the same classification level.
The federal government requires the SCI be processed, stored, used or discussed in a Sensitive compartmented information facility (SCIF).
Access
Eligibility for access to SCI is determined by a Single Scope Background Investigation (SSBI) or periodic reinvestigation. Because the same investigation is used to grant Top Secret security clearances, the two are often written together as TS//SCI. Eligibility alone does not confer access to any specific SCI material; it is simply a qualification. One must receive explicit permission to access an SCI control system or compartment. This process may include a polygraph or other approved investigative or adjudicative action.
Once it is determined a person should have access to an SCI compartment, they sign a nondisclosure agreement, are "read in" or indoctrinated, and the fact of this access is recorded in a local access register or in a comput
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https://en.wikipedia.org/wiki/FLT
|
FLT may refer to:
Mathematics
Fermat's Last Theorem, in number theory
Fermat's little theorem, using modular arithmetic
Finite Legendre transform, in algebra
Medicine
Alovudine (fluorothymidine), a pharmaceutical drug
Fluorothymidine F-18, a radiolabeled pharmaceutical drug
Places
Finger Lakes Trail, New York, United States
Flitwick railway station, England
Phaeton Airport, Haiti
Organizations
Fairlight (group), a 1980s Commodore warez group
Flight Centre, an Australian travel company (founded 1982; ASX ticker:FLT)
Free Federation of Workers (), a 20th-century Puerto Rican trade union
Liberation Front of Chad (), 1965–1976
Luxembourg Tennis Federation (French: ), a sports governing body (founded 1946)
Other uses
Flutter-tonguing, in music
Foreign Language Teaching, in education
See also
FTL (disambiguation)
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https://en.wikipedia.org/wiki/SHARK
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In cryptography, SHARK is a block cipher identified as one of the predecessors of Rijndael (the Advanced Encryption Standard).
SHARK has a 64-bit block size and a 128-bit key size. It is a six-round SP-network which alternates a key mixing stage with linear and non-linear transformation layers. The linear transformation uses an MDS matrix representing a Reed–Solomon error correcting code in order to guarantee good diffusion. The nonlinear layer is composed of eight 8×8-bit S-boxes based on the function F(x) = x−1 over GF(28).
Five rounds of a modified version of SHARK can be broken using an interpolation attack (Jakobsen and Knudsen, 1997).
See also
KHAZAD
Square
References
External links
SCAN's entry for SHARK
Block ciphers
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https://en.wikipedia.org/wiki/Nitrile
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In organic chemistry, a nitrile is any organic compound that has a functional group. The name of the compound is composed of a base, which includes the carbon of the , suffixed with "nitrile", so for example is called "propionitrile" (or propanenitrile). The prefix cyano- is used interchangeably with the term nitrile in industrial literature. Nitriles are found in many useful compounds, including methyl cyanoacrylate, used in super glue, and nitrile rubber, a nitrile-containing polymer used in latex-free laboratory and medical gloves. Nitrile rubber is also widely used as automotive and other seals since it is resistant to fuels and oils. Organic compounds containing multiple nitrile groups are known as cyanocarbons.
Inorganic compounds containing the group are not called nitriles, but cyanides instead. Though both nitriles and cyanides can be derived from cyanide salts, most nitriles are not nearly as toxic.
Structure and basic properties
The N−C−C geometry is linear in nitriles, reflecting the sp hybridization of the triply bonded carbon. The C−N distance is short at 1.16 Å, consistent with a triple bond. Nitriles are polar, as indicated by high dipole moments. As liquids, they have high relative permittivities, often in the 30s.
History
The first compound of the homolog row of nitriles, the nitrile of formic acid, hydrogen cyanide was first synthesized by C. W. Scheele in 1782. In 1811 J. L. Gay-Lussac was able to prepare the very toxic and volatile pure acid.
Arou
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https://en.wikipedia.org/wiki/DES-X
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In cryptography, DES-X (or DESX) is a variant on the DES (Data Encryption Standard) symmetric-key block cipher intended to increase the complexity of a brute-force attack. The technique used to increase the complexity is called key whitening.
The original DES algorithm was specified in 1976 with a 56-bit key size: 256 possibilities for the key. There was criticism that an exhaustive search might be within the capabilities of large governments, particularly the United States' National Security Agency (NSA). One scheme to increase the key size of DES without substantially altering the algorithm was DES-X, proposed by Ron Rivest in May 1984.
The algorithm has been included in RSA Security's BSAFE cryptographic library since the late 1980s.
DES-X augments DES by XORing an extra 64 bits of key (K1) to the plaintext before applying DES, and then XORing another 64 bits of key (K2) after the encryption:
The key size is thereby increased to 56 + (2 × 64) = 184 bits.
However, the effective key size (security) is only increased to 56+64−1−lb(M) = 119 − lb(M) = ~119 bits, where M is the number of chosen plaintext/ciphertext pairs the adversary can obtain, and lb denotes the binary logarithm. Moreover, key size drops to 88 bits given 232.5 known plaintext and using advanced slide attack.
DES-X also increases the strength of DES against differential cryptanalysis and linear cryptanalysis, although the improvement is much smaller than in the case of brute force attacks. It is estimate
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https://en.wikipedia.org/wiki/Manfred%20von%20Ardenne
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Manfred baron von Ardenne (; 20 January 190726 May 1997) was a German researcher and applied physicist and inventor. He took out approximately 600 patents in fields including electron microscopy, medical technology, nuclear technology, plasma physics, and radio and television technology. From 1928 to 1945, he directed his private research laboratory Forschungslaboratorium für Elektronenphysik. For ten years after World War II, he worked in the Soviet Union on their atomic bomb project and was awarded a Stalin Prize. Upon his return to the then East Germany, he started another private laboratory, Forschungsinstitut Manfred von Ardenne.
Von Ardenne is seen as one of the main inventors of the television.
Career
Early years
The stormy life of von Ardenne's grandmother, Elisabeth von Ardenne (1853–1952), is said to have been be the inspiration for Effi Briest by Theodor Fontane, one of the most famous German realist novels.
Born in 1907 in Hamburg to a wealthy aristocratic family, Ardenne was the oldest of five children. In 1913, Ardenne's father, assigned to the Kriegsministerium, moved to Berlin. From Ardenne's earliest youth, he was intrigued by any form of technology, and this was fostered by his parents. Ardenne's early education was at home through private teachers. In Berlin, from 1919, Ardenne attended the Realgymnasium, where he pursued his interests in physics and technology. In a school competition, he submitted models of a camera and an alarm system, for which
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https://en.wikipedia.org/wiki/Non-measurable%20set
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In mathematics, a non-measurable set is a set which cannot be assigned a meaningful "volume". The mathematical existence of such sets is construed to provide information about the notions of length, area and volume in formal set theory. In Zermelo–Fraenkel set theory, the axiom of choice entails that non-measurable subsets of exist.
The notion of a non-measurable set has been a source of great controversy since its introduction. Historically, this led Borel and Kolmogorov to formulate probability theory on sets which are constrained to be measurable. The measurable sets on the line are iterated countable unions and intersections of intervals (called Borel sets) plus-minus null sets. These sets are rich enough to include every conceivable definition of a set that arises in standard mathematics, but they require a lot of formalism to prove that sets are measurable.
In 1970, Robert M. Solovay constructed the Solovay model, which shows that it is consistent with standard set theory without uncountable choice, that all subsets of the reals are measurable. However, Solovay's result depends on the existence of an inaccessible cardinal, whose existence and consistency cannot be proved within standard set theory.
Historical constructions
The first indication that there might be a problem in defining length for an arbitrary set came from Vitali's theorem. A more recent combinatorial construction which is similar to the construction by Robin Thomas of a non-Lebesgue measurable set
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https://en.wikipedia.org/wiki/Peter%20J.%20Weinberger
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Peter Jay Weinberger (born August 6, 1942) is a computer scientist best known for his early work at Bell Labs. He now works at Google.
Weinberger was an undergraduate at Swarthmore College, graduating in 1964. He received his PhD in mathematics (number theory) in 1969 from the University of California, Berkeley under Derrick Henry Lehmer for a thesis entitled "Proof of a Conjecture of Gauss on Class Number Two". After holding a position in the Department of Mathematics at the University of Michigan, Ann Arbor, where he continued his work in analytic number theory, he moved to AT&T Bell Labs.
At Bell Labs, Weinberger contributed to the design of the AWK programming language (he is the "W" in AWK), and the Fortran compiler f77. A detailed explanation of his contributions to AWK and other Unix tools is found in an interview transcript at Princeton University.
Another interview sheds some light on his work at Google.
When Peter Weinberger was promoted to head of Computer Science Research at Bell Labs, his picture was merged with the AT&T "death star" logo of the mid-80s, creating the PJW Face image that has appeared in innumerable locations, including T-shirts, coffee mugs, CDs, and at least one water tower. The sole remaining PJW Face at Bell Labs is somewhat in disarray, but there are plans afoot to repair it.
Prior to joining Google, Weinberger was chief technology officer at Renaissance Technologies. Weinberger has been a member of the JASON defense advisory group since
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https://en.wikipedia.org/wiki/Ramp%20%28disambiguation%29
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A Ramp or Inclined plane is a simple machine.
Ramp may also refer to:
Businesses and organisations
Ramp (company), an American financial service and technology company based in New York, NY.
Science
Ramp function, in mathematics the integral of the unit step function
Receptor activity-modifying protein (RAMP), a class of protein
(R)-1-amino-2-methoxymethylpyrrolidine, a chiral auxiliary used in the Enders SAMP/RAMP hydrazone-alkylation reaction
Transportation
Airport ramp, the area where aircraft are loaded and unloaded
Linkspan, on a ferry or a ferry slip
Interchange (road) entrance ramp/on ramp or exit ramp/off ramp, on a freeway
Speed bumps, also called ramps
Wheelchair ramp, an alternative to stairs
Parking ramp, a multi-story structure for car parking with ramps between floors
Sports
Vert ramp and mini ramp, half-pipe structures used in gravity extreme sports
Mark Ramprakash (born 1969), English cricketer nicknamed "Ramps"
Music
RAMP, a soul/jazz group from Cincinnati
Ramp, a 1991 album by Giant Sand
"Ramp! (The Logical Song)", German band Scooter's cover of the Supertramp song
Places
Ramp, West Virginia, an unincorporated community
Ramp Run, a stream in Ohio
Other uses
Allium tricoccum, ramp or ramps, common name for a wild onion or garlic, native to eastern North America
Car ramp, a simple method of raising a vehicle from the ground
Operation Ramp, an Australian Defence Force evacuation of civilians during the 2006 Lebanon War
Ramp or catwal
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https://en.wikipedia.org/wiki/Twelfth
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Twelfth can mean:
The Twelfth Amendment to the United States Constitution
The Twelfth, a Protestant celebration originating in Ireland
In mathematics:
12th, an ordinal number; as in the item in an order twelve places from the beginning, following the eleventh and preceding the thirteenth
1/12, a vulgar fraction, one part of a unit divided equally into twelve parts
Music
The note twelve scale degrees from the root (current note, in a chord)
The interval (music) (that is, gap) between the root and the twelfth note: a compound fifth
Currency
Uncia (coin), a Roman coin worth 12th of an As
See also
12 (number)
Eleventh
Thirteenth
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https://en.wikipedia.org/wiki/Landau%E2%80%93Ramanujan%20constant
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In mathematics and the field of number theory, the Landau–Ramanujan constant is the positive real number b that occurs in a theorem proved by Edmund Landau in 1908, stating that for large , the number of positive integers below that are the sum of two square numbers behaves asymptotically as
This constant b was rediscovered in 1913 by Srinivasa Ramanujan, in the first letter he wrote to G.H. Hardy.
Sums of two squares
By the sum of two squares theorem, the numbers that can be expressed as a sum of two squares of integers are the ones for which each prime number congruent to 3 mod 4 appears with an even exponent in their prime factorization. For instance, 45 = 9 + 36 is a sum of two squares; in its prime factorization, 32 × 5, the prime 3 appears with an even exponent, and the prime 5 is congruent to 1 mod 4, so its exponent can be odd.
Landau's theorem states that if is the number of positive integers less than that are the sum of two squares, then
,
where is the Landau–Ramanujan constant.
The Landau-Ramanujan constant can also be written as an infinite product:
History
This constant was stated by Landau in the limit form above; Ramanujan instead approximated as an integral, with the same constant of proportionality, and with a slowly growing error term.
References
Additive number theory
Analytic number theory
Mathematical constants
Srinivasa Ramanujan
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https://en.wikipedia.org/wiki/Eugenio%20Calabi
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Eugenio Calabi (May 11, 1923 – September 25, 2023) was an Italian-born American mathematician and the Thomas A. Scott Professor of Mathematics at the University of Pennsylvania, specializing in differential geometry, partial differential equations and their applications.
Early life and education
Calabi was born in Milan, Italy on May 11, 1923, into a Jewish family. His sister was the journalist Tullia Zevi Calabi. In 1938, the family left Italy because of the racial laws, and in 1939 arrived in the United States.
In the fall of 1939, aged only 16, Calabi enrolled at the Massachusetts Institute of Technology, studying chemical engineering. His studies were interrupted when he was drafted in the US military in 1943 and served during World War II. Upon his discharge in 1946, Calabi was able to finish his bachelor's degree under the G.I. Bill, and was a Putnam Fellow. He received a master's degree in mathematics from the University of Illinois Urbana-Champaign in 1947 and his PhD in mathematics from Princeton University in 1950. His doctoral dissertation, titled "Isometric complex analytic imbedding of Kähler manifolds", was done under the supervision of Salomon Bochner.
Academic career
From 1951 to 1955 he was an assistant professor at Louisiana State University, and he moved to the University of Minnesota in 1955, where he become a full professor in 1960. In 1964, Calabi joined the mathematics faculty at the University of Pennsylvania. Following the retirement of Hans Radem
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https://en.wikipedia.org/wiki/Cartan%27s%20theorems%20A%20and%20B
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In mathematics, Cartan's theorems A and B are two results proved by Henri Cartan around 1951, concerning a coherent sheaf on a Stein manifold . They are significant both as applied to several complex variables, and in the general development of sheaf cohomology.
Theorem B is stated in cohomological terms (a formulation that Cartan (1953, p. 51) attributes to J.-P. Serre):
Analogous properties were established by Serre (1957) for coherent sheaves in algebraic geometry, when is an affine scheme. The analogue of Theorem B in this context is as follows :
These theorems have many important applications. For instance, they imply that a holomorphic function on a closed complex submanifold, , of a Stein manifold can be extended to a holomorphic function on all of . At a deeper level, these theorems were used by Jean-Pierre Serre to prove the GAGA theorem.
Theorem B is sharp in the sense that if for all coherent sheaves on a complex manifold (resp. quasi-coherent sheaves on a noetherian scheme ), then is Stein (resp. affine); see (resp. and ).
See also
Cousin problems
References
.
.
.
Several complex variables
Topological methods of algebraic geometry
Theorems in algebraic geometry
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https://en.wikipedia.org/wiki/Geometric%20topology
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In mathematics, geometric topology is the study of manifolds and maps between them, particularly embeddings of one manifold into another.
History
Geometric topology as an area distinct from algebraic topology may be said to have originated in the 1935 classification of lens spaces by Reidemeister torsion, which required distinguishing spaces that are homotopy equivalent but not homeomorphic. This was the origin of simple homotopy theory. The use of the term geometric topology to describe these seems to have originated rather recently.
Differences between low-dimensional and high-dimensional topology
Manifolds differ radically in behavior in high and low dimension.
High-dimensional topology refers to manifolds of dimension 5 and above, or in relative terms, embeddings in codimension 3 and above. Low-dimensional topology is concerned with questions in dimensions up to 4, or embeddings in codimension up to 2.
Dimension 4 is special, in that in some respects (topologically), dimension 4 is high-dimensional, while in other respects (differentiably), dimension 4 is low-dimensional; this overlap yields phenomena exceptional to dimension 4, such as exotic differentiable structures on R4. Thus the topological classification of 4-manifolds is in principle tractable, and the key questions are: does a topological manifold admit a differentiable structure, and if so, how many? Notably, the smooth case of dimension 4 is the last open case of the generalized Poincaré conjecture; see G
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https://en.wikipedia.org/wiki/List%20of%20amateur%20mathematicians
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This is a list of amateur mathematicians—people whose primary vocation did not involve mathematics (or any similar discipline) yet made notable, and sometimes important, contributions to the field of mathematics.
Ahmes (scribe)
Ashutosh Mukherjee (lawyer)
Robert Ammann (programmer and postal worker)
John Arbuthnot (surgeon and author)
Jean-Robert Argand (shopkeeper)
Leon Bankoff (Beverly Hills dentist)
Rev. Thomas Bayes (Presbyterian minister)
Andrew Beal (businessman)
Isaac Beeckman (candlemaker)
Chester Ittner Bliss (biologist)
Napoléon Bonaparte (general)
Mary Everest Boole (homemaker, librarian)
William Bourne (innkeeper)
Nathaniel Bowditch (indentured bookkeeper)
Achille Brocot (clockmaker)
Jost Bürgi (clockmaker)
Marvin Ray Burns (veteran)
Gerolamo Cardano (medical doctor)
D. G. Champernowne (college student)
Thomas Clausen (technical assistant)
Sir James Cockle (judge)
Federico Commandino (medical doctor)
William Crabtree (merchant)
Nathan Daboll (cooper)
Felix Delastelle (bonded warehouseman)
Martin Demaine (goldsmith and glass artist)
Humphry Ditton (minister)
Harvey Dubner (engineer)
Henry Dudeney (civil servant)
Albrecht Dürer (painter)
Greg Egan (writer)
M. C. Escher (graphic artist)
Eugène Ehrhart (mathematics teacher)
John Ernest (painter)
Pasquale Joseph Federico (patent attorney)
Pierre de Fermat (lawyer)
Sarah Flannery (high school student)
Reo Fortune (anthropologist)
John G.F. Francis (research assistant)
Benjamin Franklin (printer and diplomat)
Bernard Fr
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https://en.wikipedia.org/wiki/Low-dimensional%20topology
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In mathematics, low-dimensional topology is the branch of topology that studies manifolds, or more generally topological spaces, of four or fewer dimensions. Representative topics are the structure theory of 3-manifolds and 4-manifolds, knot theory, and braid groups. This can be regarded as a part of geometric topology. It may also be used to refer to the study of topological spaces of dimension 1, though this is more typically considered part of continuum theory.
History
A number of advances starting in the 1960s had the effect of emphasising low dimensions in topology. The solution by Stephen Smale, in 1961, of the Poincaré conjecture in five or more dimensions made dimensions three and four seem the hardest; and indeed they required new methods, while the freedom of higher dimensions meant that questions could be reduced to computational methods available in surgery theory. Thurston's geometrization conjecture, formulated in the late 1970s, offered a framework that suggested geometry and topology were closely intertwined in low dimensions, and Thurston's proof of geometrization for Haken manifolds utilized a variety of tools from previously only weakly linked areas of mathematics. Vaughan Jones' discovery of the Jones polynomial in the early 1980s not only led knot theory in new directions but gave rise to still mysterious connections between low-dimensional topology and mathematical physics. In 2002, Grigori Perelman announced a proof of the three-dimensional Poincaré
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https://en.wikipedia.org/wiki/Daryl%20F.%20Mallett
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Daryl Furumi Mallett is an American author, editor, publisher, actor, producer and screenwriter.
Early life
Daryl Furumi Mallett was born on May 3, 1969, in <<Los Angeles, California>>. His father, Dr. William Robert "Bill" Mallett (1932- ) holds a Ph.D. in chemistry and worked at Union Oil Company (Union 76). His mother, Masuko (Sano) Mallett (1938- ) is a homemaker. He has one younger sister.
Education
Mallett received a dual Interdisciplinary Humanities and Social Sciences Bachelor of Arts degree from the University of California, Riverside in 1991, specializing in Theatre Arts/Public Speaking and Creative Writing/Comparative Literatures and Languages (Speculative Fiction) under the direction of Pilgrim Award-winning author George E. Slusser. He also studied with authors like Eliud Martinez, Susan Straight, Stephen Minot, Harry Lawton, Lou Pedrotti, Stephanie Hammer, Gary Kern, Pulitzer Prize nominee Maurya Simon, actor/director Richard Russo, and Babylon 5 set designer John Iacovelli. Maulana Karenga, creator of Kwanzaa, was also his mentor for ethnic studies. Ever the overachiever, Mallett is in the process of returning to school to finish his Master of Library Information Sciences (MLIS) degree, and eventually hopes to get his MBA, MFA and PhD degrees.
Writing
In the writing world, some of Mallett's duties include being a contributing writer for Water Conditioning & Purification; editor, copyeditor and proofreader for Gryphon Books; Editor-in-Chief of Fiction at Batt
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https://en.wikipedia.org/wiki/Kurt%20Heegner
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Kurt Heegner (; 16 December 1893 – 2 February 1965) was a German private scholar from Berlin, who specialized in
radio engineering and mathematics. He is famous for his mathematical discoveries in number theory and, in particular, the Stark–Heegner theorem.
Life and career
Heegner was born and died in Berlin. In 1952, he published the Stark–Heegner theorem which he claimed was the solution to a classic number theory problem proposed by the great mathematician Gauss, the class number 1 problem. Heegner's work was not accepted for years, mainly due to his quoting of a portion of Heinrich Martin Weber's work that was known to be incorrect (though he never used this result in the proof).
Heegner's proof was accepted as essentially correct after a 1967 announcement by Bryan Birch, and definitively resolved by a paper by Harold Stark that had been delayed in publication until 1969 (Stark had independently arrived at a similar proof, but disagrees with the common notion that his proof is "more or less the same" as Heegner's). Stark attributed Heegner's mistakes to the fact he used a textbook by Weber that contained some results with incomplete proofs.
The book The Legacy of Leonhard Euler: A Tricentennial Tribute by Lokenath Debnath claims on page 64, that Heegner was a "retired Swiss mathematician", but he appears to have been neither Swiss nor retired at the time of his 1952 paper.
See also
List of amateur mathematicians
Stark–Heegner theorem
Heegner number
Heegner point
Hee
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https://en.wikipedia.org/wiki/Tectonophysics
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Tectonophysics, a branch of geophysics, is the study of the physical processes that underlie tectonic deformation. This includes measurement or calculation of the stress- and strain fields on Earth’s surface and the rheologies of the crust, mantle, lithosphere and asthenosphere.
Overview
Tectonophysics is concerned with movements in the Earth's crust and deformations over scales from meters to thousands of kilometers. These govern processes on local and regional scales and at structural boundaries, such as the destruction of continental crust (e.g. gravitational instability) and oceanic crust (e.g. subduction), convection in the Earth's mantle (availability of melts), the course of continental drift, and second-order effects of plate tectonics such as thermal contraction of the lithosphere. This involves the measurement of a hierarchy of strains in rocks and plates as well as deformation rates; the study of laboratory analogues of natural systems; and the construction of models for the history of deformation.
History
Tectonophysics was adopted as the name of a new section of AGU on April 19, 1940, at AGU's 21st Annual Meeting. According to the AGU website (https://tectonophysics.agu.org/agu-100/section-history/), using the words from Norman Bowen, the main goal of the tectonophysics section was to “designate this new borderline field between geophysics, physics and geology … for the solution of problems of tectonics.” Consequently, the claim below that the term was define
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https://en.wikipedia.org/wiki/Viktor%20Ambartsumian
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Viktor Amazaspovich Ambartsumian (; , Viktor Hamazaspi Hambardzumyan; 12 August 1996) was a Soviet Armenian astrophysicist and science administrator. One of the 20th century's top astronomers, he is widely regarded as the founder of theoretical astrophysics in the Soviet Union.
Educated at Leningrad State University (LSU) and the Pulkovo Observatory, Ambartsumian taught at LSU and founded the Soviet Union's first department of astrophysics there in 1934. He subsequently moved to Soviet Armenia, where he founded the Byurakan Observatory in 1946. It became his institutional base for the decades to come and a major center of astronomical research. He also co-founded the Armenian Academy of Sciences and led it for almost half a century—the entire post-war period. One commentator noted that "science in Armenia was synonymous with the name Ambartsumian." In 1965 Ambartsumian founded the journal Astrofizika and served as its editor for over 20 years.
Ambartsumian began retiring from the various positions he held only from the age of 80. He died at his house in Byurakan and was buried on the grounds of the observatory. He was declared a National Hero of Armenia in 1994.
Background
Ambartsumian was born in Tiflis on 18 September (5 September in Old Style), 1908 to Hripsime Khakhanian (1885–1972) and Hamazasp Hambardzumyan (1880–1966). Hripsime's father was an Armenian Apostolic priest from Tskhinvali, while Hamazasp hailed from Vardenis (Basargechar). His ancestors moved from Diyad
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https://en.wikipedia.org/wiki/S-matrix
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In physics, the S-matrix or scattering matrix relates the initial state and the final state of a physical system undergoing a scattering process. It is used in quantum mechanics, scattering theory and quantum field theory (QFT).
More formally, in the context of QFT, the S-matrix is defined as the unitary matrix connecting sets of asymptotically free particle states (the in-states and the out-states) in the Hilbert space of physical states. A multi-particle state is said to be free (non-interacting) if it transforms under Lorentz transformations as a tensor product, or direct product in physics parlance, of one-particle states as prescribed by equation below. Asymptotically free then means that the state has this appearance in either the distant past or the distant future.
While the S-matrix may be defined for any background (spacetime) that is asymptotically solvable and has no event horizons, it has a simple form in the case of the Minkowski space. In this special case, the Hilbert space is a space of irreducible unitary representations of the inhomogeneous Lorentz group (the Poincaré group); the S-matrix is the evolution operator between (the distant past), and (the distant future). It is defined only in the limit of zero energy density (or infinite particle separation distance).
It can be shown that if a quantum field theory in Minkowski space has a mass gap, the state in the asymptotic past and in the asymptotic future are both described by Fock spaces.
History
The
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https://en.wikipedia.org/wiki/Mike%20Massimino
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Michael James Massimino (born August 19, 1962) is an American professor of mechanical engineering at Columbia University and a former NASA astronaut. He is the senior advisor of space programs at the Intrepid Sea, Air & Space Museum.
Early life
Massimino was born August 19, 1962, in Oceanside, New York, and raised in Franklin Square, New York, both on Long Island. He graduated from H. Frank Carey Junior-Senior High School in Franklin Square, New York in 1980. He went on to attend Columbia University, graduating with a Bachelor of Science degree in industrial engineering in 1984. He then attended the Massachusetts Institute of Technology, graduating with a Master of Science degree in mechanical engineering and a Master of Science degree in Technology and Public Policy in 1988. He continued his education at MIT, earning a Degree of Mechanical Engineer in 1990 and a Doctor of Philosophy degree in mechanical engineering in 1992.
Career
Upon completing his B.S. degree from Columbia, Massimino worked for IBM as a systems engineer in New York City from 1984 until 1986. In 1986 he entered graduate school at the Massachusetts Institute of Technology where he conducted research on human operator control of space robotics systems in the MIT Mechanical Engineering Department's Human-machine systems Laboratory. His work resulted in the awarding of two patents. While a student at MIT he worked during the summer of 1987 as a general engineer at NASA Headquarters in the Office of Aeronau
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https://en.wikipedia.org/wiki/Ernst%20Messerschmid
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Ernst Willi Messerschmid (born 21 May 1945) is a German physicist and former astronaut.
Born in Reutlingen, Germany, Messerschmid finished the Technisches Gymnasium in Stuttgart in 1965. After two years of military service he studied physics at the University of Tübingen and Bonn, receiving a Diplom degree in 1972 and doctorate in 1976. From 1970 to 1975 he was also a visiting scientist at the CERN in Geneva, working on proton beams in accelerators and plasmas. From 1975 to 1976 he worked at the University of Freiburg and the Brookhaven National Laboratory (New York), In 1977, he joined DESY in Hamburg to work on the beam optics of the PETRA storage ring.
From 1978 to 1982, he worked at the DFVLR (the precursor of the DLR) in the Institute of Communications Technology in Oberpfaffenhofen on space-borne communications. In 1983, he was selected as one of the astronauts for the first German Spacelab mission D-1. He flew as a payload specialist on STS-61-A in 1985, spending over 168 hours in space.
After his spaceflight he became a professor at the Institut für Raumfahrtsysteme at the University of Stuttgart. From 2000 to 2004, he was head of the European Astronaut Centre in Cologne. In January 2005, he returned to the University of Stuttgart teaching on subjects of Astronautics and Space Stations.
External links
NASA biography
Spacefacts biography of Ernst Messerschmid
ESA biography of Ernst Messerschmid
1945 births
Living people
German astronauts
20th-century German physic
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https://en.wikipedia.org/wiki/Homogeneous%20function
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In mathematics, a homogeneous function is a function of several variables such that, if all its arguments are multiplied by a scalar, then its value is multiplied by some power of this scalar, called the degree of homogeneity, or simply the degree; that is, if is an integer, a function of variables is homogeneous of degree if
for every and
For example, a homogeneous polynomial of degree defines a homogeneous function of degree .
The above definition extends to functions whose domain and codomain are vector spaces over a field : a function between two -vector spaces is homogeneous of degree if
for all nonzero and This definition is often further generalized to functions whose domain is not , but a cone in , that is, a subset of such that implies for every nonzero scalar .
In the case of functions of several real variables and real vector spaces, a slightly more general form of homogeneity called positive homogeneity is often considered, by requiring only that the above identities hold for and allowing any real number as a degree of homogeneity. Every homogeneous real function is positively homogeneous. The converse is not true, but is locally true in the sense that (for integer degrees) the two kinds of homogeneity cannot be distinguished by considering the behavior of a function near a given point.
A norm over a real vector space is an example of a positively homogeneous function that is not homogeneous. A special case is the absolute value of real num
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https://en.wikipedia.org/wiki/Cousin%20problems
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In mathematics, the Cousin problems are two questions in several complex variables, concerning the existence of meromorphic functions that are specified in terms of local data. They were introduced in special cases by Pierre Cousin in 1895. They are now posed, and solved, for any complex manifold M, in terms of conditions on M.
For both problems, an open cover of M by sets Ui is given, along with a meromorphic function fi on each Ui.
First Cousin problem
The first Cousin problem or additive Cousin problem assumes that each difference
is a holomorphic function, where it is defined. It asks for a meromorphic function f on M such that
is holomorphic on Ui; in other words, that f shares the singular behaviour of the given local function. The given condition on the is evidently necessary for this; so the problem amounts to asking if it is sufficient. The case of one variable is the Mittag-Leffler theorem on prescribing poles, when M is an open subset of the complex plane. Riemann surface theory shows that some restriction on M will be required. The problem can always be solved on a Stein manifold.
The first Cousin problem may be understood in terms of sheaf cohomology as follows. Let K be the sheaf of meromorphic functions and O the sheaf of holomorphic functions on M. A global section of K passes to a global section of the quotient sheaf K/O. The converse question is the first Cousin problem: given a global section of K/O, is there a global section of K from which it aris
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https://en.wikipedia.org/wiki/Henry%20William%20Watson
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Rev. Henry William Watson FRS (25 February 1827, Marylebone, London11 January 1903, Berkswell near Coventry) was a mathematician and author of a number of mathematics books. He was an ordained priest and Cambridge Apostle.
Life
He was born at Marylebone on 25 Feb. 1827.
He was the son of Thomas Watson, R.N., and Eleanor Mary Kingston.
He was educated at King's College London and at Trinity College, Cambridge.
He graduated as second wrangler and Smith's prizeman in 1850, Dr. W. H. Besant being senior wrangler.
He became fellow in 1851, and from 1851 to 1853 was assistant tutor.
Watson formed a close friendship with James Fitzjames Stephen, who entered Trinity in 1847.
He was made a Fellow of the Royal Society in 1881. He and Francis Galton introduced the Galton–Watson process in 1875.
Books by H. W. Watson
The mathematical theory of electricity and magnetism (Volume 1: electrostatics) (Clarendon, Oxford, 1885–1889)
The mathematical theory of electricity and magnetism (Volume 2: magnetism & electrodynamics) (Clarendon, Oxford, 1885–1889)
A treatise on the application of generalised coordinates to the kinetics of a material system (Clarendon, Oxford, 1879)
A treatise on the kinetic theory of gases (Clarendon, Oxford, 1893)
References
External links
1827 births
1903 deaths
Alumni of King's College London
Alumni of Trinity College, Cambridge
Second Wranglers
Fellows of the Royal Society
19th-century English mathematicians
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https://en.wikipedia.org/wiki/Science%20and%20Engineering%20Research%20Council
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The Science and Engineering Research Council (SERC) and its predecessor the Science Research Council (SRC) were the UK agencies in charge of publicly funded scientific and engineering research activities, including astronomy, biotechnology and biological sciences, space research and particle physics, between 1965 and 1994.
History
The SERC also had oversight of:
the Royal Greenwich Observatory (RGO)
the Royal Observatory Edinburgh (ROE)
the Rutherford Appleton Laboratory (RAL)
the Daresbury Laboratory
From its formation in 1965 until 1981 it was known as the Science Research Council (SRC). The SRC had been formed in 1965 as a result of the Trend Committee enquiry into the organisation of civil science in the UK. Previously the Minister for Science had been responsible for various research activities in the Department of Scientific and Industrial Research (DSIR) and more loosely with a variety of agencies concerned with the formulation of civil scientific policy. One of the main problems addressed by the enquiry was how to decide the priorities for government funding across all areas of scientific research. Previously this task had been the responsibility of the Treasury without direct scientific advice. The other Research Councils formed in 1965 were:
the Natural Environment Research Council (NERC)
the Social Science Research Council (SSRC)
the Agricultural Research Council (ARC)
These bodies joined the Medical Research Council (MRC) which had existed since 192
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https://en.wikipedia.org/wiki/Britain%20J.%20Williams
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Britain J. Williams III is a Professor Emeritus of computer science at Kennesaw State University in Georgia, and is consultant with the school's Center For Election Systems. He has bachelor's and master's degrees in mathematics from the University of Georgia, and a PhD is in Statistics
from the University of Georgia in 1965. He joined the faculty of (then) Kennesaw State College in 1990.
He was a consultant to the Federal Election Commission during the development of their Voting System Standards in 1990 and again in 2002. He is currently a member of the National Association of State Election Directors Voting Systems Board and Chair of the Board's Technical Committee. He serves as a consultant to the states of Georgia, Maryland, Pennsylvania and Virginia, where he has certified electronic voting systems. In 2003, he wrote a defense of the Georgia electronic voting system in response to criticism of Diebold Election Systems (now Premier Election Solutions) systems levied by Bev Harris, author of Black Box Voting.
Williams appeared at a United States Election Assistance Commission (EAC) Public Hearing on the Use, Security and Reliability of Electronic Voting Systems in Washington, DC on 5 May 2004. Other technology panelists included
Dr. Avi Rubin, Johns Hopkins University, Information Security Institute; Stephen Berger, IEEE; and Dr. Ted Selker, MIT.
Williams is a recognized expert on electronic voting systems; he is a consultant to DES, the FEC, and four states. Willia
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https://en.wikipedia.org/wiki/Polyoxometalate
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In chemistry, a polyoxometalate (abbreviated POM) is a polyatomic ion, usually an anion, that consists of three or more transition metal oxyanions linked together by shared oxygen atoms to form closed 3-dimensional frameworks. The metal atoms are usually group 6 (Mo, W) or less commonly group 5 (V, Nb, Ta) and group 7 (Tc , Re) transition metals in their high oxidation states. Polyoxometalates are often colorless, orange or red diamagnetic anions. Two broad families are recognized, isopolymetalates, composed of only one kind of metal and oxide, and heteropolymetalates, composed of one metal, oxide, and a main group oxyanion (phosphate, silicate, etc.). Many exceptions to these general statements exist.
Formation
The oxides of d0 metals such as , , dissolve at high pH to give orthometalates, , , . For and , the nature of the dissolved species at high pH is less clear, but these oxides also form polyoxometalates.
As the pH is lowered, orthometalates protonate to give oxide–hydroxide compounds such as and . These species condense via the process called olation. The replacement of terminal M=O bonds, which in fact have triple bond character, is compensated by the increase in coordination number. The nonobservation of polyoxochromate cages is rationalized by the small radius of Cr(VI), which may not accommodate octahedral coordination geometry.
Condensation of the species entails loss of water and the formation of linkages. The stoichiometry for hexamolybdate is shown:
6 M
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https://en.wikipedia.org/wiki/Forb
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A forb or phorb is a herbaceous flowering plant that is not a graminoid (grass, sedge, or rush). The term is used in biology and in vegetation ecology, especially in relation to grasslands and understory. Typically these are dicots without woody stems.
Etymology
The word "forb" is derived from Greek (), meaning "pasture" or "fodder". The Hellenic spelling "phorb" is sometimes used, and in older usage this sometimes includes graminids and other plants currently not regarded as forbs.
Guilds
Forbs are members of a guilda group of plant species with broadly similar growth form. In certain contexts in ecology, guild membership may often be more important than the taxonomic relationships between organisms.
In informal classification
In addition to its use in ecology, the term "forb" may be used for subdividing popular guides to wildflowers, distinguishing them from other categories such as grasses, sedges, shrubs, and trees. Some examples of forbs are clovers, sunflowers, daylilies, and milkweed.
Examples
Linnaean taxonomy family names are given.
Acanthaceae,
Aizoaceae,
Amaranthaceae,
Apiaceae,
Apocynaceae,
Asclepiadaceae,
Asteraceae,
Balsaminaceae,
Begoniaceae,
Boraginaceae,
Brassicaceae,
Buxaceae,
Campanulaceae,
Cannabaceae,
Caryophyllaceae,
Chenopodiaceae,
Clusiaceae,
Convolvulaceae,
Crassulaceae,
Cucurbitaceae,
Cuscutaceae,
Dipsacaceae,
Ericaceae,
Euphorbiaceae,
Fabaceae,
Gentianaceae,
Geraniaceae,
Gunneraceae,
Haloragaceae,
Hydrophyllaceae,
Lamiaceae,
Lentibulariaceae,
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https://en.wikipedia.org/wiki/Henry%20Draper%20Medal
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The Henry Draper Medal is awarded every 4 years by the United States National Academy of Sciences "for investigations in astronomical physics". Named after Henry Draper, the medal is awarded with a gift of USD $15,000. The medal was established under the Draper Fund by his widow, Anna Draper, in honor of her husband, and was first awarded in 1886 to Samuel Pierpont Langley "for numerous investigations of a high order of merit in solar physics, and especially in the domain of radiant energy". It has since been awarded 45 times.
The medal has been awarded to multiple individuals in the same year: in 1977 it was awarded to Arno Allan Penzias and Robert Woodrow Wilson "for their discovery of the cosmic microwave radiation (a remnant of the very early universe), and their leading role in the discovery of interstellar molecules"; in 1989 to Riccardo Giovanelli and Martha P. Haynes "for the first three-dimensional view of some of the remarkable large-scale filamentary structures of our visible universe"; in 1993 to Ralph Asher Alpher and Robert Herman "for their insight and skill in developing a physical model of the evolution of the universe and in predicting the existence of a microwave background radiation years before this radiation was serendipitously discovered" and in 2001 to R. Paul Butler and Geoffrey Marcy "for their pioneering investigations of planets orbiting other stars via high-precision radial velocities".
List of recipients
Source: National Academy of Sciences
S
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https://en.wikipedia.org/wiki/Blastomere
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In biology, a blastomere is a type of cell produced by cell division (cleavage) of the zygote after fertilization; blastomeres are an essential part of blastula formation, and blastocyst formation in mammals.
Human blastomere characteristics
In humans, blastomere formation begins immediately following fertilization and continues through the first week of embryonic development. About 90 minutes after fertilization, the zygote divides into two cells. The two-cell blastomere state, present after the zygote first divides, is considered the earliest mitotic product of the fertilized oocyte. These mitotic divisions continue and result in a grouping of cells called blastomeres. During this process, the total size of the embryo does not increase, so each division results in smaller and smaller cells. When the zygote contains 16 to 32 blastomeres it is referred to as a morula. These are the preliminary stages in the embryo beginning to form. Once this begins, microtubules within the morula's cytosolic material in the blastomere cells can develop into important membrane functions, such as sodium pumps. These pumps allow the inside of the embryo to fill with blastocoelic fluid, which supports the further growth of life.
The blastomere is considered totipotent; that is, blastomeres are capable of developing from a single cell into a fully fertile adult organism. This has been demonstrated through studies and conjectures made with mouse blastomeres, which have been accepted as true
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https://en.wikipedia.org/wiki/James%20H.%20Newman
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James Hansen Newman (born October 16, 1956) is an American physicist and a former NASA astronaut who flew on four Space Shuttle missions.
NASA career
After graduating from Rice University in 1984, Newman did an additional year of post-doctoral work at Rice. His research interests are in atomic and molecular physics, specifically medium to low energy collisions of atoms and molecules of aeronomic interest. His doctoral work at Rice University was in the design, construction, testing, and use of a new position-sensitive detection system for measuring differential cross sections of collisions of atoms and molecules. In 1985, Dr. Newman was appointed as adjunct professor in the Department of Space Physics and Astronomy at Rice University. That same year he came to work at NASA’s Johnson Space Center, where his duties included responsibility for conducting flight crew and flight control team training for all mission phases in the areas of Orbiter propulsion, guidance, and control. He was working as a simulation supervisor when selected for the astronaut program. In that capacity, he was responsible for a team of instructors conducting flight controller training.
Selected by NASA in January 1990, Newman began astronaut training in July 1990. His technical assignments since then include: Astronaut Office Mission Support Branch where he was part of a team responsible for crew ingress/strap-in prior to launch and crew egress after landing; Mission Development Branch working on the
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https://en.wikipedia.org/wiki/Carlos%20I.%20Noriega
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Carlos Ismael Noriega (born 8 October 1959) is a Peruvian-American NASA employee, a former NASA astronaut and a retired U.S. Marine Corps lieutenant colonel.
Education
1977: Graduated from Wilcox High School, Santa Clara, California
1981: Bachelor of science degree in computer science from University of Southern California
1990: Master of science degree in computer science from the Naval Postgraduate School
1990: Master of science degree in space systems operations from the Naval Postgraduate School.
Awards and honors
2 Defense Meritorious Service Medal
Air Medal with Combat Distinguishing Device
Air Medal (Strike Flight Award)
Navy Achievement Medal
2 NASA Space Flight Medal
NASA Exceptional Service Medal
Military career
Noriega was a member of the Naval ROTC unit at the University of Southern California and received his commission in the United States Marine Corps in 1981. Following graduation from flight school, he flew CH-46 Sea Knight helicopters with HMM-165 from 1983 to 1985 at Marine Corps Air Station Kaneohe Bay, Hawaii. Noriega made two 6-month shipboard deployments in the West Pacific/Indian Ocean, including operations in support of the Multinational Peacekeeping Force in Beirut, Lebanon. He completed his tour in Hawaii as the Base Operations Officer for Marine Air Base Squadron 24. In 1986, he was transferred to MCAS Tustin, California, where he served as the aviation safety officer and instructor pilot with HMT-301. In 1988, Noriega was selected to attend
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https://en.wikipedia.org/wiki/Tadatoshi%20Akiba
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is a Japanese mathematician and politician and served as the mayor of the city of Hiroshima, Japan from 1999 to 2011.
Early life
He studied mathematics at the University of Tokyo, receiving a B.S. in 1966 and an M.S. in 1968. He continued his studies under John Milnor at the Massachusetts Institute of Technology, earning his PhD in mathematics in 1970. He took teaching jobs at a series of universities: State University of New York at Stony Brook (1970), Tufts University (1972–1986), and Hiroshima Shudo University (1986–1997). His research was on topology, with an interest in homotopy groups.
While at Tufts, Akiba established the Hibakusha Travel Grant program, which brought several American print and broadcast journalists annually to Hiroshima in August, to craft stories about the city (and typically about the experiences of those exposed to the atomic bomb in 1945).
Political career
As a member of the Social Democratic Party, he was elected to the House of Representatives, and served from 1990 to 1999. He assumed office as mayor of Hiroshima in February, 1999, and was reelected to this position in 2003 and in April 2007.
Peace activities
As mayor, he has been a visible peace activist. He is active in the Mayors for Peace organization, serving as the president of their World Conference. The 2020 Vision Campaign launched in 2003, which aims to eliminate nuclear weapons, has earned Mayors for Peace the "World Citizenship Award" from the Nuclear Age Peace Foundation in 200
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https://en.wikipedia.org/wiki/Rodolfo%20Neri%20Vela
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Rodolfo Neri Vela (born 19 February 1952) is a Mexican scientist and astronaut who flew aboard a NASA Space Shuttle mission in the year 1985. He is the second Latin American to have traveled to space.
Personal
Neri was born in Chilpancingo, Guerrero, Mexico. He is a professor for the Telecommunications Department in the Electrical Engineering Division of the Engineering Faculty, at the National Autonomous University of Mexico (UNAM). He is of Native American, Spanish and Italian ancestry.
Education
Neri was a High School student at Escuela Nacional Preparatoria 2. Neri received a bachelor's degree in mechanical and electrical engineering, National Autonomous University of Mexico (UNAM) 1975, and received a master's degree in science, specialized in telecommunications systems, in 1976 from the University of Essex, England. Neri then received a doctorate degree in electromagnetic radiation from the University of Birmingham in 1979 and performed one year of postdoctoral research in waveguides at the University of Birmingham.
Career
Neri has worked in the Institute of Electrical and Electronics Engineers, United States; The Institution of Electrical Engineers, UK; Asociación Mexicana de Ingenieros en Comunicaciones Eléctricas y Electrónicas, Mexico; and Colegio de Ingenieros Mecánicos y Electricistas, Mexico.
Neri has also worked as an Institute of Electrical Research, Mexico, in the Radio communications Group, doing research and system planning on antenna theory and design,
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https://en.wikipedia.org/wiki/Ellis%20Clarke
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Sir Ellis Emmanuel Innocent Clarke (28 December 191730 December 2010) was the first President of Trinidad and Tobago and the second and last Governor-General. He was one of the main architects of Trinidad and Tobago's 1962 Independence constitution.
Early life
Clarke attended Saint Mary's College, winning an Island Scholarship in Mathematics in 1938. Ellis Clarke attended University College London of the University of London, where he received a Bachelor of Law degree and was called to the bar at Gray's Inn. He returned to Port of Spain in 1941, taking up private practice there.
Political career
He served as Solicitor-General from 1954 to 1956, Deputy Colonial Secretary 1956–57, and Attorney General 1957–62. After Independence in 1962 he served as Ambassador to the United States, Canada and Mexico, and Permanent Representative to the United Nations.
In 1972 he succeeded Sir Solomon Hochoy as Governor General. When Trinidad and Tobago became a republic in 1976, Clarke was unanimously elected the country's first President by the electoral college, which comprised the elected members of both Houses of Parliament. He was re-elected by the People's National Movement-controlled electoral college and completed his second term in 1987. Disagreements with the new National Alliance for Reconstruction government resulted in Clarke's decision not to seek a third term. He was succeeded by Noor Hassanali.
Clarke was invested as a Companion of St Michael and St George by Queen Elizab
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https://en.wikipedia.org/wiki/Amagat%27s%20law
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Amagat's law or the law of partial volumes describes the behaviour and properties of mixtures of ideal (as well as some cases of non-ideal) gases. It is of use in chemistry and thermodynamics. It is named after Emile Amagat.
Overview
Amagat's law states that the extensive volume V = Nv of a gas mixture is equal to the sum of volumes Vi of the K component gases, if the temperature T and the pressure p remain the same:
This is the experimental expression of volume as an extensive quantity.
According to Amagat's law of partial volume, the total volume of a non-reacting mixture of gases at constant temperature and pressure should be equal to the sum of the individual partial volumes of the constituent gases. So if are considered to be the partial volumes of components in the gaseous mixture, then the total volume would be represented as
Both Amagat's and Dalton's laws predict the properties of gas mixtures. Their predictions are the same for ideal gases. However, for real (non-ideal) gases, the results differ. Dalton's law of partial pressures assumes that the gases in the mixture are non-interacting (with each other) and each gas independently applies its own pressure, the sum of which is the total pressure. Amagat's law assumes that the volumes of the component gases (again at the same temperature and pressure) are additive; the interactions of the different gases are the same as the average interactions of the components.
The interactions can be interpreted in terms of
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https://en.wikipedia.org/wiki/Clasper
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In biology, a clasper is a male anatomical structure found in some groups of animals, used in mating.
Male cartilaginous fish have claspers formed from the posterior portion of their pelvic fin which serve to channel semen into the female's cloaca during mating. The act of mating in some fish including sharks usually includes one of the claspers raised to allow water into the siphon through a specific orifice. The clasper is then inserted into the cloaca, where it opens like an umbrella to anchor its position. The siphon then begins to contract, expelling water and sperm. The claspers of many shark species have spines or hooks, which may hold them in place during copulation. Male chimaeras have cephalic claspers (tenacula) on their heads, which are thought to aid in holding the female during mating.
In entomology, it is a structure in male insects that is used to hold the female during copulation (see Lepidoptera genitalia for more).
See also
Sexual coercion among animals
References
Fish anatomy
Insect anatomy
Animal reproductive system
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https://en.wikipedia.org/wiki/On%20the%20Cruelty%20of%20Really%20Teaching%20Computer%20Science
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"On the Cruelty of Really Teaching Computing Science" is a 1988 scholarly article by E. W. Dijkstra which argues that computer programming should be understood as a branch of mathematics, and that the formal provability of a program is a major criterion for correctness.
Despite the title, most of the article is on Dijkstra’s attempt to put computer science into a wider perspective within science, teaching being addressed as a corollary at the end.
Specifically, Dijkstra made a “proposal for an introductory programming course for freshmen” that
consisted of Hoare logic as an uninterpreted formal system.
Debate over feasibility
Since the term "software engineering" was coined, formal verification has almost always been considered too resource-intensive to be feasible. In complex applications, the difficulty of correctly specifying what the program should do in the first place is also a common source of error. Other methods of software testing are generally employed to try to eliminate bugs and many other factors are considered in the measurement of software quality.
Until the end of his life, Dijkstra maintained that the central challenges of computing hadn't been met to his satisfaction, due to an insufficient emphasis on program correctness (though not obviating other requirements, such as maintainability and efficiency).
Pedagogical legacy
Computer science as taught today does not follow of Dijkstra's advice. The curricula generally emphasize techniques for manag
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https://en.wikipedia.org/wiki/List%20of%20partition%20topics
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Generally, a partition is a division of a whole into non-overlapping parts. Among the kinds of partitions considered in mathematics are
partition of a set or an ordered partition of a set,
partition of a graph,
partition of an integer,
partition of an interval,
partition of unity,
partition of a matrix; see block matrix, and
partition of the sum of squares in statistics problems, especially in the analysis of variance,
quotition and partition, two ways of viewing the operation of division of integers.
Integer partitions
Composition (number theory)
Ewens's sampling formula
Ferrers graph
Glaisher's theorem
Landau's function
Partition function (number theory)
Pentagonal number theorem
Plane partition
Quotition and partition
Rank of a partition
Crank of a partition
Solid partition
Young tableau
Young's lattice
Set partitions
Bell number
Bell polynomials
Dobinski's formula
Cumulant
Data clustering
Equivalence relation
Exact cover
Knuth's Algorithm X
Dancing Links
Exponential formula
Faà di Bruno's formula
Feshbach–Fano partitioning
Foliation
Frequency partition
Graph partition
Kernel of a function
Lamination (topology)
Matroid partitioning
Multipartition
Multiplicative partition
Noncrossing partition
Ordered partition of a set
Partition calculus
Partition function (quantum field theory)
Partition function (statistical mechanics)
Derivation of the partition
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https://en.wikipedia.org/wiki/Persistence%20of%20a%20number
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In mathematics, the persistence of a number is the number of times one must apply a given operation to an integer before reaching a fixed point at which the operation no longer alters the number.
Usually, this involves additive or multiplicative persistence of a non-negative integer, which is how often one has to replace the number by the sum or product of its digits until one reaches a single digit. Because the numbers are broken down into their digits, the additive or multiplicative persistence depends on the radix. In the remainder of this article, base ten is assumed.
The single-digit final state reached in the process of calculating an integer's additive persistence is its digital root. Put another way, a number's additive persistence counts how many times we must sum its digits to arrive at its digital root.
Examples
The additive persistence of 2718 is 2: first we find that 2 + 7 + 1 + 8 = 18, and then that 1 + 8 = 9. The multiplicative persistence of 39 is 3, because it takes three steps to reduce 39 to a single digit: 39 → 27 → 14 → 4. Also, 39 is the smallest number of multiplicative persistence 3.
Smallest numbers of a given multiplicative persistence
In base 10, there is thought to be no number with a multiplicative persistence > 11: this is known to be true for numbers up to 1020,000. The smallest numbers with persistence 0, 1, 2, ... are:
0, 10, 25, 39, 77, 679, 6788, 68889, 2677889, 26888999, 3778888999, 277777788888899.
The search for these numbers can
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