|
1990 In Science
The year 1990 in science and technology involved some significant events. Astronomy and space exploration * January 24 – Japan launches the Hiten spacecraft, the first lunar probe launched by a country other than the Soviet Union or the United States. * February 14 – The ''Pale Blue Dot'' photograph of Earth is sent back from the ''Voyager 1'' probe after completing its primary mission, from around 3.5 billion miles away. * April 24 – The Space Shuttle ''Discovery'' places the Hubble Space Telescope into orbit. * August 16 – Steven Balbus makes his first discovery leading to elucidation of magnetorotational instability. * October 13 – Earth-grazing meteoroid of 13 October 1990: A 44 kilogram, 41.5 km/s meteoroid passes above Czechoslovakia and Poland at 97.9 km. It is the first time calculations of the orbit of such a body based on photographic records from two distant places is made. Biology * The term "rewilding" is first used in print. Computer science * ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hiten (spacecraft)
The Hiten spacecraft (ひてん, ), given the English name Celestial Maiden and known before launch as MUSES-A ( Mu Space Engineering Spacecraft A), part of the MUSES Program, was built by the Institute of Space and Astronautical Science of Japan and launched on January 24, 1990. It was Japan's first lunar probe, the first robotic lunar probe since the Soviet Union's Luna 24 in 1976, and the first lunar probe launched by a country other than the Soviet Union or the United States. The spacecraft was named after flying heavenly beings in Buddhism. Hiten was to be placed into a highly elliptical Earth orbit with an apogee of 476,000 km, which would swing past the Moon. However, the injection took place with a delta-v deficit of 50 m/s, resulting in an apogee of only 290,000 km. The deficiency was corrected and the probe continued on its mission. On the first lunar swing-by, Hiten released a small orbiter, Hagoromo (はごろも, named after the feather mantle of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Microsoft
Microsoft Corporation is an American multinational technology corporation producing computer software, consumer electronics, personal computers, and related services headquartered at the Microsoft Redmond campus located in Redmond, Washington, United States. Its best-known software products are the Windows line of operating systems, the Microsoft Office suite, and the Internet Explorer and Edge web browsers. Its flagship hardware products are the Xbox video game consoles and the Microsoft Surface lineup of touchscreen personal computers. Microsoft ranked No. 21 in the 2020 Fortune 500 rankings of the largest United States corporations by total revenue; it was the world's largest software maker by revenue as of 2019. It is one of the Big Five American information technology companies, alongside Alphabet, Amazon, Apple, and Meta. Microsoft was founded by Bill Gates and Paul Allen on April 4, 1975, to develop and sell BASIC interpreters for the Altair 8800. It rose to do ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Braid Group
A braid (also referred to as a plait) is a complex structure or pattern formed by interlacing two or more strands of flexible material such as textile yarns, wire, or hair. The simplest and most common version is a flat, solid, three-stranded structure. More complex patterns can be constructed from an arbitrary number of strands to create a wider range of structures (such as a fishtail braid, a five-stranded braid, rope braid, a French braid and a waterfall braid). The structure is usually long and narrow with each component strand functionally equivalent in zigzagging forward through the overlapping mass of the others. It can be compared with the process of weaving, which usually involves two separate perpendicular groups of strands (warp and weft). Historically, the materials used have depended on the indigenous plants and animals available in the local area. During the Industrial Revolution, mechanized braiding equipment was invented to increase production. The braiding te ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Iwahori–Hecke Algebra
In mathematics, the Iwahori–Hecke algebra, or Hecke algebra, named for Erich Hecke and Nagayoshi Iwahori, is a deformation of the group algebra of a Coxeter group. Hecke algebras are quotients of the group rings of Artin braid groups. This connection found a spectacular application in Vaughan Jones' construction of new invariants of knots. Representations of Hecke algebras led to discovery of quantum groups by Michio Jimbo. Michael Freedman proposed Hecke algebras as a foundation for topological quantum computation. Hecke algebras of Coxeter groups Start with the following data: * (''W'', ''S'') is a Coxeter system with the Coxeter matrix ''M'' = (''m''''st''), * ''R'' is a commutative ring with identity. * is a family of units of ''R'' such that ''qs'' = ''qt'' whenever ''s'' and ''t'' are conjugate in ''W'' * ''A'' is the ring of Laurent polynomials over Z with indeterminates ''qs'' (and the above restriction that ''qs'' = ''qt'' whenever ''s'' and ''t'' are conjugate ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Homology (mathematics)
In mathematics, homology is a general way of associating a sequence of algebraic objects, such as abelian groups or modules, with other mathematical objects such as topological spaces. Homology groups were originally defined in algebraic topology. Similar constructions are available in a wide variety of other contexts, such as abstract algebra, groups, Lie algebras, Galois theory, and algebraic geometry. The original motivation for defining homology groups was the observation that two shapes can be distinguished by examining their holes. For instance, a circle is not a disk because the circle has a hole through it while the disk is solid, and the ordinary sphere is not a circle because the sphere encloses a two-dimensional hole while the circle encloses a one-dimensional hole. However, because a hole is "not there", it is not immediately obvious how to define a hole or how to distinguish different kinds of holes. Homology was originally a rigorous mathematical method for defi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ruth Lawrence
Ruth Elke Lawrence-Neimark ( he, רות אלקה לורנס-נאימרק, born 2 August 1971) is a British–Israeli mathematician and an associate professor of mathematics at the Einstein Institute of Mathematics, Hebrew University of Jerusalem, and a researcher in knot theory and algebraic topology. Outside academia, she is best known for having been a child prodigy in mathematics. Early life Ruth Lawrence was born in Brighton, England. Her parents, Harry Lawrence and Sylvia Greybourne, were both computer consultants. When Lawrence was five, her father gave up his job so that he could educate her at home. Education At the age of nine, Lawrence gained an O-level in mathematics, setting a new age record (later surpassed in 2001 when Arran Fernandez successfully sat GCSE mathematics aged five). Also at the age of nine she achieved a Grade A at A-level pure mathematics. In 1981 Lawrence passed the Oxford University entrance examination in mathematics, joining St Hugh's College ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Euler System
In mathematics, an Euler system is a collection of compatible elements of Galois cohomology groups indexed by fields. They were introduced by in his work on Heegner points on modular elliptic curves, which was motivated by his earlier paper and the work of . Euler systems are named after Leonhard Euler because the factors relating different elements of an Euler system resemble the Euler factors of an Euler product. Euler systems can be used to construct annihilators of ideal class groups or Selmer groups, thus giving bounds on their orders, which in turn has led to deep theorems such as the finiteness of some Tate-Shafarevich groups. This led to Karl Rubin's new proof of the main conjecture of Iwasawa theory, considered simpler than the original proof due to Barry Mazur and Andrew Wiles. Definition Although there are several definitions of special sorts of Euler system, there seems to be no published definition of an Euler system that covers all known cases. But it is poss ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Victor Kolyvagin
Victor Alexandrovich Kolyvagin (russian: Виктор Александрович Колывагин, born 11 March, 1955) is a Russian mathematician who wrote a series of papers on Euler systems, leading to breakthroughs on the Birch and Swinnerton-Dyer conjecture, and Iwasawa's conjecture for cyclotomic fields. His work also influenced Andrew Wiles's work on Fermat's Last Theorem. Career Kolyvagin received his Ph.D. in Mathematics in 1981 from Moscow State University, where his advisor was Yuri I. Manin. He then worked at Steklov Institute of Mathematics in Moscow until 1994. Since 1994 he has been a professor of mathematics in the United States. He was a professor at Johns Hopkins University until 2002 when he became the first person to hold the Mina Rees Chair in mathematics at the Graduate Center Faculty at The City University of New York. Awards In 1990 he received the of the USSR Academy of Sciences The Academy of Sciences of the Soviet Union was the highest scient ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Harvard University Press
Harvard University Press (HUP) is a publishing house established on January 13, 1913, as a division of Harvard University, and focused on academic publishing. It is a member of the Association of American University Presses. After the retirement of William P. Sisler in 2017, the university appointed as Director George Andreou. The press maintains offices in Cambridge, Massachusetts near Harvard Square, and in London, England. The press co-founded the distributor TriLiteral LLC with MIT Press and Yale University Press. TriLiteral was sold to LSC Communications in 2018. Notable authors published by HUP include Eudora Welty, Walter Benjamin, E. O. Wilson, John Rawls, Emily Dickinson, Stephen Jay Gould, Helen Vendler, Carol Gilligan, Amartya Sen, David Blight, Martha Nussbaum, and Thomas Piketty. The Display Room in Harvard Square, dedicated to selling HUP publications, closed on June 17, 2009. Related publishers, imprints, and series HUP owns the Belknap Press imprint, whi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thomas W
Thomas may refer to: People * List of people with given name Thomas * Thomas (name) * Thomas (surname) * Saint Thomas (other) * Thomas Aquinas (1225–1274) Italian Dominican friar, philosopher, and Doctor of the Church * Thomas the Apostle * Thomas (bishop of the East Angles) (fl. 640s–650s), medieval Bishop of the East Angles * Thomas (Archdeacon of Barnstaple) (fl. 1203), Archdeacon of Barnstaple * Thomas, Count of Perche (1195–1217), Count of Perche * Thomas (bishop of Finland) (1248), first known Bishop of Finland * Thomas, Earl of Mar (1330–1377), 14th-century Earl, Aberdeen, Scotland Geography Places in the United States * Thomas, Illinois * Thomas, Indiana * Thomas, Oklahoma * Thomas, Oregon * Thomas, South Dakota * Thomas, Virginia * Thomas, Washington * Thomas, West Virginia * Thomas County (other) * Thomas Township (other) Elsewhere * Thomas Glacier (Greenland) Arts, entertainment, and media * ''Thomas'' (Burton novel) 1969 nove ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Time (magazine)
''Time'' (stylized in all caps) is an American news magazine based in New York City. For nearly a century, it was published Weekly newspaper, weekly, but starting in March 2020 it transitioned to every other week. It was first published in New York City on March 3, 1923, and for many years it was run by its influential co-founder, Henry Luce. A European edition (''Time Europe'', formerly known as ''Time Atlantic'') is published in London and also covers the Middle East, Africa, and, since 2003, Latin America. An Asian edition (''Time Asia'') is based in Hong Kong. The South Pacific edition, which covers Australia, New Zealand, and the Pacific Islands, is based in Sydney. Since 2018, ''Time'' has been published by Time USA, LLC, owned by Marc Benioff, who acquired it from Meredith Corporation. History ''Time'' has been based in New York City since its first issue published on March 3, 1923, by Briton Hadden and Henry Luce. It was the first weekly news magazine in the United St ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pokémon
(an abbreviation for in Japan) is a Japanese media franchise managed by The Pokémon Company, founded by Nintendo, Game Freak, and Creatures (company), Creatures, the owners of the trademark and copyright of the franchise. In terms of what each of those companies do, Game Freak develop the main games; Creatures provides support through their Pokémon CG Studio which does 3D models for the pokémon in the games, as well as developing some spin-off titles, and producing the ''Pokémon Trading Card Game''; Nintendo was the original publisher of the series and since the 2000s, helps publishing the games in their consoles in overseas markets outside of Japan and The Pokémon Company is then jointly owned by them and is set up to deal with the licensing, production, publishing, marketing and deals across the world featuring Pokémon as a media franchise. The franchise was created by Satoshi Tajiri in 1996, and is centered around fictional creatures called "List of Pokémon, P ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
