source
stringlengths 31
207
| text
stringlengths 12
1.5k
|
|---|---|
https://en.wikipedia.org/wiki/Hyperbolic%20manifold
|
In mathematics, a hyperbolic manifold is a space where every point looks locally like hyperbolic space of some dimension. They are especially studied in dimensions 2 and 3, where they are called hyperbolic surfaces and hyperbolic 3-manifolds, respectively. In these dimensions, they are important because most manifolds can be made into a hyperbolic manifold by a homeomorphism. This is a consequence of the uniformization theorem for surfaces and the geometrization theorem for 3-manifolds proved by Perelman.
Rigorous definition
A hyperbolic -manifold is a complete Riemannian -manifold of constant sectional curvature .
Every complete, connected, simply-connected manifold of constant negative curvature is isometric to the real hyperbolic space . As a result, the universal cover of any closed manifold of constant negative curvature is . Thus, every such can be written as where is a torsion-free discrete group of isometries on . That is, is a discrete subgroup of . The manifold has finite volume if and only if is a lattice.
Its thick–thin decomposition has a thin part consisting of tubular neighborhoods of closed geodesics and ends which are the product of a Euclidean ()-manifold and the closed half-ray. The manifold is of finite volume if and only if its thick part is compact.
Examples
The simplest example of a hyperbolic manifold is hyperbolic space, as each point in hyperbolic space has a neighborhood isometric to hyperbolic space.
A simple non-trivial example, howe
|
https://en.wikipedia.org/wiki/Georg%20Heinrich%20Thiessen
|
Georg Heinrich Thiessen (19 January 1914 – 3 July 1961) was a German astronomer.
After graduating, Georg Thiessen studied physics and mathematics and received his doctorate in 1940 under Richard Becker at Göttingen Georg August University. He joined the Fraunhofer Institute of the Institute for High Frequency Research in Freiburg in Breisgau in 1943, where he met Karl-Otto Kiepenheuer. In January 1945 he was transferred to the observatory in Hamburg-Bergedorf, where he was employed as assistant and later as 'Observator' from 1946 to 1953. In 1953 he habilitated on the subject of magnetic fields of the sun, he believed in the existence of a global solar magnetic field. He was promoted to professor in 1959.
On 3 of July 1961 he was killed in a frontal collision with a tram, his wife was seriously injured in this accident.
A crater on the farside of the moon (Thiessen) has been named after him since 1970.
Sunspots
Thiessen extensively studied sunspots. He discovered that the granulation, filling the entire solar surface outside sunspots, cannot be observed in the umbra. However, his observations revealed that there are small brighter spots (so-called umbra dots) inside the umbra. They are difficult to observe due to their small size and because of the high brightness contrast between the sunspot umbra and the surrounding photosphere.
External links
MitAG 15 (1962) 17 (obituary, in German)
Katalog der Deutschen Nationalbibliothek
Author Query Results
Nachruf auf Georg T
|
https://en.wikipedia.org/wiki/RNS
|
RNS may be an initialism for:
Rabid Neurosis, a music piracy organisation
RNS formalism in the string theory of physics
Reactive nitrogen species
Regulatory News Service
Religion News Service
Rennes - Saint-Jacques Airport, France, IATA code
Residue numeral system in mathematics
Responsive neurostimulation device, an epilepsy treatment
"R.N.S.", a song by Slaughterhouse from Southpaw: Music from and Inspired By the Motion Picture
|
https://en.wikipedia.org/wiki/Cusp%20neighborhood
|
In mathematics, a cusp neighborhood is defined as a set of points near a cusp singularity.
Cusp neighborhood for a Riemann surface
The cusp neighborhood for a hyperbolic Riemann surface can be defined in terms of its Fuchsian model.
Suppose that the Fuchsian group G contains a parabolic element g. For example, the element t ∈ SL(2,Z) where
is a parabolic element. Note that all parabolic elements of SL(2,C) are conjugate to this element. That is, if g ∈ SL(2,Z) is parabolic, then for some h ∈ SL(2,Z).
The set
where H is the upper half-plane has
for any where is understood to mean the group generated by g. That is, γ acts properly discontinuously on U. Because of this, it can be seen that the projection of U onto H/G is thus
.
Here, E is called the neighborhood of the cusp corresponding to g.
Note that the hyperbolic area of E is exactly 1, when computed using the canonical Poincaré metric. This is most easily seen by example: consider the intersection of U defined above with the fundamental domain
of the modular group, as would be appropriate for the choice of T as the parabolic element. When integrated over the volume element
the result is trivially 1. Areas of all cusp neighborhoods are equal to this, by the invariance of the area under conjugation.
References
Hyperbolic geometry
Riemann surfaces
|
https://en.wikipedia.org/wiki/Tempo%20and%20Mode%20in%20Evolution
|
Tempo and Mode in Evolution (1944) was George Gaylord Simpson's seminal contribution to the evolutionary synthesis, which integrated the facts of paleontology with those of genetics and natural selection.
Simpson argued that the microevolution of population genetics was sufficient in itself to explain the patterns of macroevolution observed by paleontology. Simpson also highlighted the distinction between tempo and mode. "Tempo" encompasses "evolutionary rates … their acceleration and deceleration, the conditions of exceptionally slow or rapid evolutions, and phenomena suggestive of inertia and momentum," while "mode" embraces "the study of the way, manner, or pattern of evolution, a study in which tempo is a basic factor, but which embraces considerably more than tempo."
Simpson's Tempo and Mode attempted to draw out several distinct generalizations:
Evolution's tempo can impart information about its mode.
Multiple tempos can be found in the fossil record: horotelic (medium tempo), bradytelic (slow tempo), and tachytelic (rapid tempo).
The facts of paleontology are consistent with the genetical theory of natural selection. Moreover, theories such as orthogenesis, Lamarckism, mutation pressures, and macromutations either are false or play little to no role.
Most evolution—"nine-tenths"—occurs by the steady phyletic transformation of whole lineages (anagenesis). This contrasts with Ernst Mayr's interpretation of speciation by splitting, particularly allopatric and perip
|
https://en.wikipedia.org/wiki/KT%20%28energy%29
|
kT (also written as kBT) is the product of the Boltzmann constant, k (or kB), and the temperature, T. This product is used in physics as a scale factor for energy values in molecular-scale systems (sometimes it is used as a unit of energy), as the rates and frequencies of many processes and phenomena depend not on their energy alone, but on the ratio of that energy and kT, that is, on (see Arrhenius equation, Boltzmann factor). For a system in equilibrium in canonical ensemble, the probability of the system being in state with energy E is proportional to .
More fundamentally, kT is the amount of heat required to increase the thermodynamic entropy of a system by k.
In physical chemistry, as kT often appears in the denominator of fractions (usually because of Boltzmann distribution), sometimes β = 1/kT is used instead of kT, turning into .
RT
RT is the product of the molar gas constant, R, and the temperature, T. This product is used in physics and chemistry as a scaling factor for energy values in macroscopic scale (sometimes it is used as a pseudo-unit of energy), as many processes and phenomena depend not on the energy alone, but on the ratio of energy and RT, i.e. E/RT. The SI units for RT are joules per mole (J/mol).
It differs from kT only by a factor of the Avogadro constant, NA. Its dimension is energy or ML2T−2, expressed in SI units as joules (J):
kT = RT/NA
References
Thermodynamics
Statistical mechanics
|
https://en.wikipedia.org/wiki/Artificial%20immune%20system
|
In artificial intelligence, artificial immune systems (AIS) are a class of computationally intelligent, rule-based machine learning systems inspired by the principles and processes of the vertebrate immune system. The algorithms are typically modeled after the immune system's characteristics of learning and memory for use in problem-solving.
Definition
The field of artificial immune systems (AIS) is concerned with abstracting the structure and function of the immune system to computational systems, and investigating the application of these systems towards solving computational problems from mathematics, engineering, and information technology. AIS is a sub-field of biologically inspired computing, and natural computation, with interests in machine learning and belonging to the broader field of artificial intelligence.
AIS is distinct from computational immunology and theoretical biology that are concerned with simulating immunology using computational and mathematical models towards better understanding the immune system, although such models initiated the field of AIS and continue to provide a fertile ground for inspiration. Finally, the field of AIS is not concerned with the investigation of the immune system as a substrate for computation, unlike other fields such as DNA computing.
History
AIS emerged in the mid-1980s with articles authored by Farmer, Packard and Perelson (1986) and Bersini and Varela (1990) on immune networks. However, it was only in the mid-1990s th
|
https://en.wikipedia.org/wiki/Meanings%20of%20minor%20planet%20names%3A%2030001%E2%80%9331000
|
30001–30100
|-id=004
| 30004 Mikewilliams || || Mike Williams (born 1952) was a lead engineer at the University of Arizona's Lunar and Planetary Laboratory. ||
|-id=005
| 30005 Stevenchen || || Steven Chen (born 1996), a finalist in the 2014 Intel Science Talent Search, a science competition for high school seniors, for his chemistry project. ||
|-id=007
| 30007 Johnclarke || || John Anthony Clarke (born 1996), a finalist in the 2014 Intel Science Talent Search, a science competition for high school seniors, for his earth and planetary science project. ||
|-id=008
| 30008 Aroncoraor || || Aron Coraor (born 1996), a finalist in the 2014 Intel Science Talent Search, a science competition for high school seniors, for his chemistry project. ||
|-id=012
| 30012 Sohamdaga || || Soham Daga (born 1996), a finalist in the 2014 Intel Science Talent Search, a science competition for high school seniors, for his behavioral and social sciences project. ||
|-id=017
| 30017 Shaundatta || || Shaun Datta (born 1996), a finalist in the 2014 Intel Science Talent Search, a science competition for high school seniors, for his physics project. ||
|-id=022
| 30022 Kathibaker || || Kathi Baker (1954–2014) was involved with administrative support for the NASA HiRISE mission to Mars, as well as supporting many faculty, staff and students at the University of Arizona's Lunar and Planetary Laboratory. Most recently, Kathi served as executive assistant to the LPL Director. ||
|-id=024
|
|
https://en.wikipedia.org/wiki/Modelling%20of%20General%20Systems
|
MGS (a General Model of Simulation) is a domain-specific language used for specification and simulation of dynamical systems with dynamical structure, developed at IBISC (Computer Science, Integrative Biology and Complex Systems) at Université d'Évry Val-d'Essonne (University of Évry). MGS is particularly aimed at modelling biological systems.
The MGS computational model is a generalisation of cellular automata, Lindenmayer systems, Paun systems and other computational formalisms inspired by chemistry and biology. It manipulates collections - sets of positions, filled with some values, in a lattice with a user-defined topology.
External links
Project home page
Simulation programming languages
|
https://en.wikipedia.org/wiki/Closeness%20%28mathematics%29
|
Closeness is a basic concept in topology and related areas in mathematics. Intuitively, we say two sets are close if they are arbitrarily near to each other. The concept can be defined naturally in a metric space where a notion of distance between elements of the space is defined, but it can be generalized to topological spaces where we have no concrete way to measure distances.
The closure operator closes a given set by mapping it to a closed set which contains the original set and all points close to it. The concept of closeness is related to limit point.
Definition
Given a metric space a point is called close or near to a set if
,
where the distance between a point and a set is defined as
where inf stands for infimum. Similarly a set is called close to a set if
where
.
Properties
if a point is close to a set and a set then and are close (the converse is not true!).
closeness between a point and a set is preserved by continuous functions
closeness between two sets is preserved by uniformly continuous functions
Closeness relation between a point and a set
Let be some set. A relation between the points of and the subsets of is a closeness relation if it satisfies the following conditions:
Let and be two subsets of and a point in .
If then is close to .
if is close to then
if is close to and then is close to
if is close to then is close to or is close to
if is close to and for every point , is close to , then is close to .
Top
|
https://en.wikipedia.org/wiki/Human%20genetics
|
Human genetics is the study of inheritance as it occurs in human beings. Human genetics encompasses a variety of overlapping fields including: classical genetics, cytogenetics, molecular genetics, biochemical genetics, genomics, population genetics, developmental genetics, clinical genetics, and genetic counseling.
Genes are the common factor of the qualities of most human-inherited traits. Study of human genetics can answer questions about human nature, can help understand diseases and the development of effective treatment and help us to understand the genetics of human life. This article describes only basic features of human genetics; for the genetics of disorders please see: medical genetics.
Genetic differences and inheritance patterns
Inheritance of traits for humans are based upon Gregor Mendel's model of inheritance. Mendel deduced that inheritance depends upon discrete units of inheritance, called factors or genes.
Autosomal dominant inheritance
Autosomal traits are associated with a single gene on an autosome (non-sex chromosome)—they are called "dominant" because a single copy—inherited from either parent—is enough to cause this trait to appear. This often means that one of the parents must also have the same trait, unless it has arisen due to an unlikely new mutation. Examples of autosomal dominant traits and disorders are Huntington's disease and achondroplasia.
Autosomal recessive inheritance
Autosomal recessive traits is one pattern of inheritance fo
|
https://en.wikipedia.org/wiki/Quasiperiodic%20motion
|
In mathematics and theoretical physics, quasiperiodic motion is in rough terms the type of motion executed by a dynamical system containing a finite number (two or more) of incommensurable frequencies.
That is, if we imagine that the phase space is modelled by a torus T (that is, the variables are periodic like angles), the trajectory of the system is modelled by a curve on T that wraps around the torus without ever exactly coming back on itself.
A quasiperiodic function on the real line is the type of function (continuous, say) obtained from a function on T, by means of a curve
R → T
which is linear (when lifted from T to its covering Euclidean space), by composition. It is therefore oscillating, with a finite number of underlying frequencies. (NB the sense in which theta functions and the Weierstrass zeta function in complex analysis are said to have quasi-periods with respect to a period lattice is something distinct from this.)
The theory of almost periodic functions is, roughly speaking, for the same situation but allowing T to be a torus with an infinite number of dimensions.
References
See also
Quasiperiodicity
Dynamical systems
|
https://en.wikipedia.org/wiki/Christian%20Ehrenfried%20Weigel
|
Christian Ehrenfried von Weigel (24 May 1748 – 8 August 1831) was a Swedish-born German scientist and, beginning in 1774, a professor of chemistry, pharmacy, botany, and mineralogy at the University of Greifswald.
Biography
Born in Stralsund, in 1771 he received his medical doctorate from the University of Göttingen, having studied under Johann Christian Erxleben. In 1806, Weigel was ennobled and carried from then on a von in his name. He became the personal physician of the Swedish royal house two years later. Among other things, Weigel developed a cooling heat exchanger (German ) (1771), which was later improved upon by Justus von Liebig and then became known as the Liebig condenser (). Furthermore, the honeysuckle genus Weigela is named after him.
In 1792, he was elected a foreign member of the Royal Swedish Academy of Sciences.
References
External links
Weigel biography
1748 births
1831 deaths
Pteridologists
Botanists with author abbreviations
18th-century German botanists
18th-century German chemists
German mycologists
German untitled nobility
People from Stralsund
People from Swedish Pomerania
Academic staff of the University of Greifswald
Members of the Royal Swedish Academy of Sciences
University of Göttingen alumni
19th-century German chemists
|
https://en.wikipedia.org/wiki/Allan%20Birnbaum
|
Allan Birnbaum (May 27, 1923 – July 1, 1976) was an American statistician who contributed to statistical inference, foundations of statistics, statistical genetics, statistical psychology, and history of statistics.
Life and career
Birnbaum was born in San Francisco. His parents were Russian-born Orthodox Jews. He studied mathematics at the University of California, Berkeley, doing a premedical programme at the same time. After taking a bachelor's degree in mathematics in 1945, he spent two years doing graduate courses in science, mathematics and philosophy, planning perhaps a career in the philosophy of science. One of his philosophy teachers, Hans Reichenbach, suggested he combine philosophy with science.
He went to Columbia University to do a PhD with Abraham Wald but, when Wald died in a plane crash, Birnbaum asked Erich Leo Lehmann, who was visiting Columbia to take him on. Birnbaum's thesis and his early work was very much in the spirit of Lehmann's classic text Testing Statistical Hypotheses.
Birnbaum stayed at Columbia until 1959 when he moved to the Courant Institute of Mathematical Sciences, becoming a full Professor of Statistics in 1963. He travelled a good deal and liked Britain especially. In 1975 he accepted a post at the City University, London, and worked with The Open University on their course M341 "Fundamentals of statistical inference" (with Adrian Smith). He took his life in 1976.
The article in the Leading Personalities volume opens with the declara
|
https://en.wikipedia.org/wiki/Statistical%20genetics
|
Statistical genetics is a scientific field concerned with the development and application of statistical methods for drawing inferences from genetic data. The term is most commonly used in the context of human genetics. Research in statistical genetics generally involves developing theory or methodology to support research in one of three related areas:
population genetics - Study of evolutionary processes affecting genetic variation between organisms
genetic epidemiology - Studying effects of genes on diseases
quantitative genetics - Studying the effects of genes on 'normal' phenotypes
Statistical geneticists tend to collaborate closely with geneticists, molecular biologists, clinicians and bioinformaticians. Statistical genetics is a type of computational biology.
References
External links
|
https://en.wikipedia.org/wiki/Franck%E2%80%93Condon%20principle
|
The Franck–Condon principle (named for James Franck and Edward Condon) is a rule in spectroscopy and quantum chemistry that explains the intensity of vibronic transitions (the simultaneous changes in electronic and vibrational energy levels of a molecule due to the absorption or emission of a photon of the appropriate energy). The principle states that during an electronic transition, a change from one vibrational energy level to another will be more likely to happen if the two vibrational wave functions overlap more significantly.
Overview
The Franck–Condon principle has a well-established semiclassical interpretation based on the original contributions of James Franck. Electronic transitions are relatively instantaneous compared with the time scale of nuclear motions, therefore if the molecule is to move to a new vibrational level during the electronic transition, this new vibrational level must be instantaneously compatible with the nuclear positions and momenta of the vibrational level of the molecule in the originating electronic state. In the semiclassical picture of vibrations (oscillations) of a simple harmonic oscillator, the necessary conditions can occur at the turning points, where the momentum is zero.
In the quantum mechanical picture, the vibrational levels and vibrational wavefunctions are those of quantum harmonic oscillators, or of more complex approximations to the potential energy of molecules, such as the Morse potential. Figure 1 illustrates the Franc
|
https://en.wikipedia.org/wiki/Work%20hardening
|
In materials science, work hardening, also known as strain hardening, is the strengthening of a metal or polymer by plastic deformation. Work hardening may be desirable, undesirable, or inconsequential, depending on the context.
This strengthening occurs because of dislocation movements and dislocation generation within the crystal structure of the material. Many non-brittle metals with a reasonably high melting point as well as several polymers can be strengthened in this fashion. Alloys not amenable to heat treatment, including low-carbon steel, are often work-hardened. Some materials cannot be work-hardened at low temperatures, such as indium, however others can be strengthened only via work hardening, such as pure copper and aluminum.
Undesirable work hardening
An example of undesirable work hardening is during machining when early passes of a cutter inadvertently work-harden the workpiece surface, causing damage to the cutter during the later passes. Certain alloys are more prone to this than others; superalloys such as Inconel require machining strategies that take it into account.
For metal objects designed to flex, such as springs, specialized alloys are usually employed in order to avoid work hardening (a result of plastic deformation) and metal fatigue, with specific heat treatments required to obtain the necessary characteristics.
Intentional work hardening
An example of desirable work hardening is that which occurs in metalworking processes that intentionally
|
https://en.wikipedia.org/wiki/Uniformly%20connected%20space
|
In topology and related areas of mathematics a uniformly connected space or Cantor connected space is a uniform space U such that every uniformly continuous function from U to a discrete uniform space is constant.
A uniform space U is called uniformly disconnected if it is not uniformly connected.
Properties
A compact uniform space is uniformly connected if and only if it is connected
Examples
every connected space is uniformly connected
the rational numbers and the irrational numbers are disconnected but uniformly connected
See also
connectedness
References
Cantor, Georg Über Unendliche, lineare punktmannigfaltigkeiten, Mathematische Annalen. 21 (1883) 545-591.
Uniform spaces
|
https://en.wikipedia.org/wiki/Java%20Cryptography%20Architecture
|
In computing, the Java Cryptography Architecture (JCA) is a framework for working with cryptography using the Java programming language. It forms part of the Java security API, and was first introduced in JDK 1.1 in the package.
The JCA uses a "provider"-based architecture and contains a set of APIs for various purposes, such as encryption, key generation and management, secure random-number generation, certificate validation, etc. These APIs provide an easy way for developers to integrate security into application code.
See also
Java Cryptography Extension
Bouncy Castle (cryptography)
External links
Official JCA guides: JavaSE6, JavaSE7, JavaSE8, JavaSE9, JavaSE10, JavaSE11
Java platform
Cryptographic software
|
https://en.wikipedia.org/wiki/Dilation%20%28metric%20space%29
|
In mathematics, a dilation is a function from a metric space into itself that satisfies the identity
for all points , where is the distance from to and is some positive real number.
In Euclidean space, such a dilation is a similarity of the space. Dilations change the size but not the shape of an object or figure.
Every dilation of a Euclidean space that is not a congruence has a unique fixed point that is called the center of dilation. Some congruences have fixed points and others do not.
See also
Homothety
Dilation (operator theory)
References
Metric geometry
|
https://en.wikipedia.org/wiki/Geminus
|
Geminus of Rhodes (), was a Greek astronomer and mathematician, who flourished in the 1st century BC. An astronomy work of his, the Introduction to the Phenomena, still survives; it was intended as an introductory astronomy book for students. He also wrote a work on mathematics, of which only fragments quoted by later authors survive.
Life
Nothing is known about the life of Geminus. It is not even certain that he was born in Rhodes, but references to mountains on Rhodes in his astronomical works suggests that he worked there. His dates are not known with any certainty either. A passage in his works referring to the Annus Vagus (Wandering Year) of the Egyptian calendar of 120 years before his own time, has been used to imply a date of c. 70 BC for the time of writing, which would be consistent with the idea that he may have been a pupil of Posidonius, but a date as late as 50 AD has also been suggested.
The crater Geminus on the Moon is named after him.
Astronomy
The only work of Geminus to survive is his Introduction to the Phenomena (), often just called the Isagoge. This introductory astronomy book, based on the works of earlier astronomers such as Hipparchus, was intended to teach astronomy for beginning students in the subject. In it, Geminus describes the zodiac and the motion of the Sun, the constellations, the celestial sphere, days and nights, the risings and settings of the zodiacal signs, luni-solar periods and their application to calendars, phases of the Moon,
|
https://en.wikipedia.org/wiki/Project%20Snowblind
|
Project: Snowblind is a first-person shooter video game developed by Crystal Dynamics and published by Eidos Interactive for PlayStation 2, Xbox and Microsoft Windows. The game follows soldier Nathan Frost, who is enhanced with nanotechnology following injuries on a mission and sent against a military regime known as the Republic. Players control Frost through a series of linear levels, using enhancements both in combat and to manipulate security devices such as cameras. The online multiplayer allows up to sixteen players to take part in modes ranging from team-based to solo battles.
Beginning development in 2004, the game was Crystal Dynamics' first attempt at a first-person shooter and originally planned as part of the Deus Ex series with consultation from original developer Ion Storm. The game eventually evolved into its own product, but retained gameplay elements from its Deus Ex roots. Reception of the game was generally positive.
Gameplay
Similar to the Deus Ex series, the focus of Project: Snowblinds gameplay is giving the player a variety of choices on how to approach any given situation. Although the game is generally linear, most levels feature multiple paths through any given area, allowing players to either rush in guns blazing or attempt to find a more stealthy side-path. Unlike Deus Ex, the game is entirely centered around pure combat, but nonetheless provides the player with multiple options regarding every battle. Every weapon in the game has a secondary fir
|
https://en.wikipedia.org/wiki/Kauko%20Armas%20Nieminen
|
Kauko Armas Nieminen (15 February 1929 – 2010) was a Finnish self-taught physicist.
Nieminen was born in Kuopio, Finland. Although he was most known for his works in physics, he did not have any academic training or degree in physics, but was entirely self-taught. He had a bachelor's degree in law from the University of Helsinki.
Nieminen's research and theories in physics were unusual. The basis of his work was the theory of "ether vortices". In principle, the theory claimed that the universe is filled with ether, and as the ends of the ether come close to each other vortices appear. The center of a vortex is an elementary particle. Nieminen claimed his theories can explain gravity, quantum phenomena, ball lightnings and the creation of the world.
Nieminen was also very critical towards the established scientific community, though not towards students of science, and had in fact been frequently invited to lecture to the same amidst mutual respect and good humor.
Nieminen had published several books. Nieminen did not use a commercial publisher or advertisement agency, but instead published and distributed his books and advertisements himself.
Kauko Nieminen was a deputy member of the city council of Helsinki from 2001 to 2004. In the 2000 municipal elections, he was a candidate from the joint election list of the independent candidates in the Helsinki Metropolitan area.
Publications
Eetterin fysiikkaa (1980)
Eetteripyörteet voimina (1984)
Sähkö eetteripyörteitä (1987)
|
https://en.wikipedia.org/wiki/Velocity%20%28disambiguation%29
|
Velocity is a quantity in physics that is related to speed.
Velocity may also refer to:
Computing and technology
Apache Velocity, a Java template engine
Velocity (JavaScript library)
Velocity (memory cache), from Microsoft
Velocity (software development), a measure of productivity
Arts, entertainment, and media
Velocity (album), by The Vels
Velocity (character), a comic book character
Velocity (film), a re-edited version of the 1960 film The Wild Ride, with new footage
Velocity (newspaper), in Louisville, Kentucky
Velocity (novel), by Dean Koontz
Velocity (TV network), a Discovery Communications channel
Velocity (video game), a 2012 shoot 'em up video game
WWE Velocity, a wrestling television show
Other uses
Velocity SE, an entry-level homebuilt aircraft
Velocity XL, a high-performance homebuilt aircraft
USS Velocity, several U.S. Navy warships
Velocity of money, a monetary economics concept
Velocity Tower, a tower in Sheffield
Velo-city, a series of cycle planning conferences
Velocity Frequent Flyer, frequent-flyer program of Virgin Australia whose airline call sign is "Velocity"
|
https://en.wikipedia.org/wiki/Vicinal
|
Vicinal may refer to:
Vicinal (chemistry), stands for any two functional groups bonded to two adjacent atoms.
Vicinal (logology), a word where all letters have alphabetic neighbors.
Vicinal tramway or Buurtspoor, a system of narrow gauge tramways or local railways in Belgium.
In materials science, a "vicinal substrate" is a thin-film substrate whose surface normal deviates slightly from a major crystallographic axis.
|
https://en.wikipedia.org/wiki/Wess%E2%80%93Zumino%E2%80%93Witten%20model
|
In theoretical physics and mathematics, a Wess–Zumino–Witten (WZW) model, also called a Wess–Zumino–Novikov–Witten model, is a type of two-dimensional conformal field theory named after Julius Wess, Bruno Zumino, Sergei Novikov and Edward Witten. A WZW model is associated to a Lie group (or supergroup), and its symmetry algebra is the affine Lie algebra built from the corresponding Lie algebra (or Lie superalgebra). By extension, the name WZW model is sometimes used for any conformal field theory whose symmetry algebra is an affine Lie algebra.
Action
Definition
For a Riemann surface, a Lie group, and a (generally complex) number, let us define the -WZW model on at the level . The model is a nonlinear sigma model whose action is a functional of a field :
Here, is equipped with a flat Euclidean metric, is the partial derivative, and is the Killing form on the Lie algebra of . The Wess–Zumino term of the action is
Here is the completely anti-symmetric tensor, and is the Lie bracket.
The Wess–Zumino term is an integral over a three-dimensional manifold whose boundary is .
Topological properties of the Wess–Zumino term
For the Wess–Zumino term to make sense, we need the field to have an extension to . This requires the homotopy group to be trivial, which is the case in particular for any compact Lie group .
The extension of a given to is in general not unique.
For the WZW model to be well-defined,
should not depend on the choice of the extension.
The We
|
https://en.wikipedia.org/wiki/ZP
|
ZP may refer to:
Mathematics and science
Zp, the ring of p-adic integers
Zona pellucida (or egg coat), a glycoprotein layer around an oocyte
Z/pZ, the cyclic group of integers modulo p
Organisations
Zila Parishad ():
District Councils of Bangladesh
District Councils of India
Zjednoczona Prawica, the Polish United Right party
ZP, US Navy prefix for airship patrol squadrons, 1942–1961
People
Zach Parise, American ice hockey player
ZP Theart, former vocalist for British power metal band DragonForce
José Luis Rodríguez Zapatero, former Spanish prime minister, via popular nickname "ZP" (Zapatero Presidente)
|
https://en.wikipedia.org/wiki/Semantic%20gap
|
The semantic gap characterizes the difference between two descriptions of an object by different linguistic representations, for instance languages or symbols. According to Andreas M. Hein, the semantic gap can be defined as "the difference in meaning between constructs formed within different representation systems". In computer science, the concept is relevant whenever ordinary human activities, observations, and tasks are transferred into a computational representation.
More precisely the gap means the difference between ambiguous formulation of contextual knowledge in a powerful language (e.g. natural language) and its sound, reproducible and computational representation in a formal language (e.g. programming language). Semantics of an object depends on the context it is regarded within. For practical application this means any formal representation of real world tasks requires the translation of the contextual expert knowledge of an application (high-level) into the elementary and reproducible operations of a computing machine (low-level). Since natural language allows the expression of tasks which are impossible to compute in a formal language there are no means to automate this translation in a general way. Moreover, the examination of languages within the Chomsky hierarchy indicates that there is no formal and consequently automated way of translating from one language into another above a certain level of expressional power.
Theoretical background
The yet unproven
|
https://en.wikipedia.org/wiki/Roberto%20Ierusalimschy
|
Roberto Ierusalimschy (; born 21 May 1960) is a Brazilian computer scientist, known for creating the Lua programming language. He holds a PhD in Computer Science from the Pontifical Catholic University of Rio de Janeiro where he has an appointment as a full professor of informatics. He did a post-doc at University of Waterloo in 1992 and was visiting professor at Stanford University in 2012. He is the leading architect and the author of Programming in Lua. He also created LPeg, a Lua library for implementing parsing expression grammars.
In 2021, Roberto created Building a Programming Language, a project-based learning program where students learn how to build a programming language from scratch.
References
External links
1960 births
Brazilian computer scientists
Brazilian Jews
Living people
People from Rio de Janeiro (city)
Pontifical Catholic University of Rio de Janeiro alumni
Academic staff of the Pontifical Catholic University of Rio de Janeiro
Programming language designers
|
https://en.wikipedia.org/wiki/BNA
|
BNA may refer to:
Bahrain News Agency, the state news agency of Bahrain
Bakhtar News Agency, the state news agency in Afghanistan
Basle Nomina Anatomica, the first revision of anatomic nomenclature
Burma National Army
Bulgarian National Alliance
British Naturalists' Association
British Neuroscience Association
British Newspaper Archive
British North America, a former name for Canada
British North America Acts, the original Constitutional Acts of Canada
Bureau of National Affairs, a U.S. commercial publisher
Banco de la Nación Argentina
BNA Records, a record label
Bridged nucleic acid
BNA: Brand New Animal, an anime television series
BNA, IATA airport code of Nashville International Airport
BNA, National Rail station code of Burnage railway station, Manchester, England
Banco Nacional de Angola
|
https://en.wikipedia.org/wiki/Exotic
|
Exotic may refer to:
Mathematics and physics
Exotic R4, a differentiable 4-manifold, homeomorphic but not diffeomorphic to the Euclidean space R4
Exotic sphere, a differentiable n-manifold, homeomorphic but not diffeomorphic to the ordinary n-sphere
Exotic atom, an atom with one or more electrons replaced by other negatively charged particles
Exotic hadron
Exotic baryon, bound states of 3 quarks and additional particles
Exotic meson, non-quark model mesons
Exotic matter, a hypothetical concept of particle physics
Music
"Exotic" (1963 song), a song by The Sentinals from the 1963 album Surf Crazy - Original Surfin' Hits
"Exotic" (Lil Baby song), 2018
"Exotic" (Priyanka Chopra song), a 2012 song by Priyanka Chopra featuring Pitbull
Flora and fauna
Exotic pet
Exotic Shorthair, a breed of cat
Exotic species (or introduced species), a species not native to an area
Other
Exotic dancer, a type of dancer or stripper
Exotic derivative, a type of financial derivative
See also
Exoticism
Exotica (disambiguation)
|
https://en.wikipedia.org/wiki/Key%20signature%20%28cryptography%29
|
In cryptography, a key signature is the result of a third-party applying a cryptographic signature to a representation of a cryptographic key. This is usually done as a form of assurance or verification: If "Alice" has signed "Bob's" key, it can serve as an assurance to another party, say "Eve", that the key actually belongs to Bob, and that Alice has personally checked and attested to this.
The representation of the key that is signed is usually shorter than the key itself, because most public-key signature schemes can only encrypt or sign short lengths of data. Some derivative of the public key fingerprint may be used, i.e. via hash functions.
See also
Key (cryptography)
Public key certificate
Key management
|
https://en.wikipedia.org/wiki/Lie%20theory
|
In mathematics, the mathematician Sophus Lie ( ) initiated lines of study involving integration of differential equations, transformation groups, and contact of spheres that have come to be called Lie theory. For instance, the latter subject is Lie sphere geometry. This article addresses his approach to transformation groups, which is one of the areas of mathematics, and was worked out by Wilhelm Killing and Élie Cartan.
The foundation of Lie theory is the exponential map relating Lie algebras to Lie groups which is called the Lie group–Lie algebra correspondence. The subject is part of differential geometry since Lie groups are differentiable manifolds. Lie groups evolve out of the identity (1) and the tangent vectors to one-parameter subgroups generate the Lie algebra. The structure of a Lie group is implicit in its algebra, and the structure of the Lie algebra is expressed by root systems and root data.
Lie theory has been particularly useful in mathematical physics since it describes the standard transformation groups: the Galilean group, the Lorentz group, the Poincaré group and the conformal group of spacetime.
Elementary Lie theory
The one-parameter groups are the first instance of Lie theory. The compact case arises through Euler's formula in the complex plane. Other one-parameter groups occur in the split-complex number plane as the unit hyperbola
and in the dual number plane as the line
In these cases the Lie algebra parameters have names: angle, hyperbolic an
|
https://en.wikipedia.org/wiki/Laughlin
|
Laughlin may refer to:
Places
Laughlin, California
Laughlin, Nevada
Laughlin Air Force Base
Laughlin (Nevada gaming area)
Other uses
Laughlin (surname)
Laughlin City, a fictional town in Alberta, Canada in the 2000 movie X-Men
Laughlin wavefunction, an ansatz for the ground state of a two-dimensional electron gas (physics)
Homer Laughlin China Company
See also
Lachlan (disambiguation)
Lochlann
McLaughlin (disambiguation)
Loughlin
Laflin, Pennsylvania
Fordyce L. Laflin
|
https://en.wikipedia.org/wiki/Mollifier
|
In mathematics, mollifiers (also known as approximations to the identity) are smooth functions with special properties, used for example in distribution theory to create sequences of smooth functions approximating nonsmooth (generalized) functions, via convolution. Intuitively, given a function which is rather irregular, by convolving it with a mollifier the function gets "mollified", that is, its sharp features are smoothed, while still remaining close to the original nonsmooth (generalized) function.
They are also known as Friedrichs mollifiers after Kurt Otto Friedrichs, who introduced them.
Historical notes
Mollifiers were introduced by Kurt Otto Friedrichs in his paper , which is considered a watershed in the modern theory of partial differential equations. The name of this mathematical object had a curious genesis, and Peter Lax tells the whole story in his commentary on that paper published in Friedrichs' "Selecta". According to him, at that time, the mathematician Donald Alexander Flanders was a colleague of Friedrichs: since he liked to consult colleagues about English usage, he asked Flanders an advice on how to name the smoothing operator he was using. Flanders was a puritan, nicknamed by his friends Moll after Moll Flanders in recognition of his moral qualities: he suggested to call the new mathematical concept a "mollifier" as a pun incorporating both Flanders' nickname and the verb 'to mollify', meaning 'to smooth over' in a figurative sense.
Previously,
|
https://en.wikipedia.org/wiki/Allan%20Alcorn
|
Allan Alcorn (born January 1, 1948) is an American pioneering engineer and computer scientist best known for creating Pong, one of the first video games.
Atari and Pong
Alcorn grew up in San Francisco, California, and attended the University of California, Berkeley, graduating with a Bachelor of Science degree in electrical engineering and computer sciences in 1971.
He worked for the pioneering video company Ampex, where he met Ted Dabney and several other people that would end up being constants through the Atari, Inc., Apple, Cyan Engineering and Pizza Time Theater (now known as Chuck E. Cheese's) companies.
Alcorn was the designer of the video arcade game Pong, creating it under the direction of Nolan Bushnell and Dabney. Pong was a hit in the 1970s.
In addition to direct involvement with all the breakout Atari products, such as the Atari 2600, Alcorn was involved at some of the historic meetings of Steve Wozniak and Steve Jobs (at that time an Atari employee) presenting their Apple I prototype.
Alcorn was the person who hired Steve Jobs when he applied for a job at Atari in 1974. Jobs had seen a help-wanted ad in the San Jose Mercury newspaper for Atari that said "Have fun, make money." He showed up in the lobby of the video game manufacturer wearing sandals and disheveled hair, and told the personnel director that he wouldn't leave until he was given a job.
Al Alcorn, then chief engineer at Atari, was called and told, "We’ve got a hippie kid in the lobby. He says
|
https://en.wikipedia.org/wiki/Valery%20Fabrikant
|
Valery Iosifovich Fabrikant (, , ; born 28 January 1940) is a former associate professor of mechanical engineering at Concordia University in Montreal, Quebec, Canada. On 24 August 1992, after years of increasingly disruptive behaviour at the university, he shot and killed four colleagues and wounded one staff member.
His case stimulated much research and debate about gun control, and how universities should manage difficult employees. By 1994, the university gathered over 200,000 signatures with the Coalition for Gun Control on a petition to ban the private ownership of handguns in Canada. After the Cowan Report criticized the university for being too "vague" and "slow" in dealing with Fabrikant, in 1995 they appointed an advisor to implement a "Code of Rights & Responsibilities", and later a "Code of Ethics", adopted in 1997, and created civil behaviour and conflict resolution initiatives like the Peace and Conflict Resolution Series in 2003.
He was sentenced to life in prison and was denied parole or temporary leave in 2015 and again in 2022. After he filed numerous court proceedings, the Quebec Superior Court declared him a vexatious litigant, in 2000.
Background
Born in Belarus (then in the Soviet Union), Fabrikant emigrated to Canada in 1979. Although he claimed to be a political dissident, journalists from the Montreal Gazette later found that he had been dismissed from numerous positions in the USSR because of disruptive behaviour.
Fabrikant was hired at Concordia
|
https://en.wikipedia.org/wiki/Chemical%20test
|
In chemistry, a chemical test is a qualitative or quantitative procedure designed to identify, quantify, or characterise a chemical compound or chemical group.
Purposes
Chemical testing might have a variety of purposes, such as to:
Determine if, or verify that, the requirements of a specification, regulation, or contract are met
Decide if a new product development program is on track: Demonstrate proof of concept
Demonstrate the utility of a proposed patent
Determine the interactions of a sample with other known substances
Determine the composition of a sample
Provide standard data for other scientific, medical, and Quality assurance functions
Validate suitability for end-use
Provide a basis for Technical communication
Provide a technical means of comparison of several options
Provide evidence in legal proceedings
Biochemical tests
Clinistrips quantitatively test for sugar in urine
The Kastle-Meyer test tests for the presence of blood
Salicylate testing is a category of drug testing that is focused on detecting salicylates such as acetylsalicylic acid for either biochemical or medical purposes.
The Phadebas test tests for the presence of saliva for forensic purposes
Iodine solution tests for starch
The Van Slyke determination tests for specific amino acids
The Zimmermann test tests for ketosteroids
Seliwanoff's test differentiates between aldose and ketose sugars
Test for lipids: add ethanol to sample, then shake; add water to the solution, and shake aga
|
https://en.wikipedia.org/wiki/G.%20S.%20Carr
|
George Shoobridge Carr (1837–1914) was a British mathematician. He wrote Synopsis of Pure Mathematics (1886). This book, first published in England in 1880, was read and studied closely by mathematician Srinivasa Ramanujan when he was a teenager. Ramanujan had already produced many theorems by the age of 15.
Carr was a private coach for the Tripos mathematics examinations at the University of Cambridge, and the Synopsis was written as a study guide for those examinations.
External links
Amitabha Sen, The Legacy of Mr. Carr, A Gift for the Gifted, parabaas.com, 1999
1837 births
19th-century British mathematicians
1914 deaths
20th-century British mathematicians
|
https://en.wikipedia.org/wiki/Orestes%20Cendrero
|
Orestes Cendrero was a Spanish naturalist and professor of biology at Instituto Nacional de Segunda Enseñanza in Santander. He was a colombophilia researcher, (studied pigeons), and was editor of the pigeon scientific journal: Boletín Colombófilo Español.
Bibliography
Lecciones de Historia Natural acomodadas al cuestionario oficial. Santander.s.e. Cendrero * Curso cíclico de ciencias físico-naturales (primer año). Cendrero Curiel, Orestes. Santander.s.e. .1935.2ª ed.Un vol. 8º.182 pág+125 fig.
Nociones de Historia Natural. Cendrero Curiel, Orestes. Santander.J. Martínez .1917.1ª ed.Un Curiel, Orestes.1929.2ª ed.Un vol. 4º.201.
vol. 4º.288.
Curso elemental de historia natural: botánica . Cendrero Curiel, Orestes. Buenos Aires: López. 1961. AR. 10a ed. Botánica. Filosofía vegetal. Taxonomía vegetal. Anatomía vegetal.
Nociones de historía natural. Orestes Cendrero Curiel. Tercera edición corregida y aumentada. Media piel nueva. Imprenta y encuadernacion de Antonio Andrey y cia. Año 1922. 333pag
Spanish ornithologists
Spanish naturalists
Spanish biologists
Year of birth missing
Year of death missing
|
https://en.wikipedia.org/wiki/Categorification
|
In mathematics, categorification is the process of replacing set-theoretic theorems with category-theoretic analogues. Categorification, when done successfully, replaces sets with categories, functions with functors, and equations with natural isomorphisms of functors satisfying additional properties. The term was coined by Louis Crane.
The reverse of categorification is the process of decategorification. Decategorification is a systematic process by which isomorphic objects in a category are identified as equal. Whereas decategorification is a straightforward process, categorification is usually much less straightforward. In the representation theory of Lie algebras, modules over specific algebras are the principal objects of study, and there are several frameworks for what a categorification of such a module should be, e.g., so called (weak) abelian categorifications.
Categorification and decategorification are not precise mathematical procedures, but rather a class of possible analogues. They are used in a similar way to the words like 'generalization', and not like 'sheafification'.
Examples
One form of categorification takes a structure described in terms of sets, and interprets the sets as isomorphism classes of objects in a category. For example, the set of natural numbers can be seen as the set of cardinalities of finite sets (and any two sets with the same cardinality are isomorphic). In this case, operations on the set of natural numbers, such as addition and
|
https://en.wikipedia.org/wiki/Fiber%20%28disambiguation%29
|
A fiber is a long strand of material.
Fiber or Fibre may also refer to:
Arts, entertainment, and media
Healthcare
Dietary fiber
Myofiber, or muscle fiber, strands of muscle tissue
Nerve fiber, strands of nervous tissue
Mathematics and technology
Fiber (computer science)
Fiber (mathematics)
Fiber laser (or fibre laser), a laser in which the active gain medium is an optical fiber doped with rare-earth elements
Fiber-optic communication
Google Fiber, part of the Access division of Alphabet Inc.; provides fiber-to-the-premises service (i.e., broadband Internet and IPTV) in the United States
Optical fiber
Other uses
Fiber crop, three main groups: cordage fiber (used in production of rope), filling fiber (used to stuff upholstery), and textile fiber (used in production of cloth)
Natural fiber
Synthetic fiber
|
https://en.wikipedia.org/wiki/Size%20Strength%20classification
|
In geology, size strength classification is a two-parameter rock classification based on the strength of intact rock and the spacing of discontinuities in the rock mass. It was developed by Louis and Franklin (1970-75).
The size-strength approach to rock mass characterisation has been found helpful in various mining and civil engineering applications.
The concept of block size is analogous to that of grain size but on macroscopic scale. The rock is considered as a conglomerate of discrete intact blocks bounded by joints. The behaviour of this conglomerate depends on the size and strength of a typical block.
Block size is defined as the average diameter of a typical rock block in the unit to be classified. On the surface block size is measured by observing exposed rock surface. Underground block size is measured from drill cores. The intact strength of the rock material may be estimated by using a rock hammer.
Rock mass classification
|
https://en.wikipedia.org/wiki/George%20Irving%20Bell
|
George Irving Bell (August 4, 1926 – May 28, 2000) was an American physicist, biologist and mountaineer, and a grandson of John Joseph Seerley. He died in 2000 from complications of leukemia after surgery.
Education
Bell received a bachelor's degree in physics from Harvard University in 1947. He studied theoretical physics with Hans Bethe at Cornell University, obtaining his doctorate in 1951.
Physics
Immediately after receiving his PhD, Bell came to the Los Alamos Scientific Laboratory and joined the "T Division." At the time, this division was primarily occupied in the design of the first thermonuclear weapon. Bell contributed by solving problems of neutron transport.
Such problems are also crucial in the design and analysis of nuclear reactors, so it was natural that Bell became a leading expert on the physics of reactors. He co-authored the book Nuclear Reactor Theory with Samuel Glasstone.
Biology
Bell's interests turned to biology in the 1960s, creating quantitative models in immunology. He headed the Theoretical Biology and Biophysics group at Los Alamos from 1974 to 1990. He also worked on mathematical models in biophysics. In 1988, he became the founding director of the Center for Human Genome Studies, which became a major participant in the Human Genome Project. He was director for only one year (simultaneously acting as the head of T Division and the group leader for the Theoretical Biology and Biophysics group), and retired from Los Alamos in 1990. He continue
|
https://en.wikipedia.org/wiki/Vaughan%20Pratt
|
Vaughan Pratt (born April 12, 1944) is a Professor Emeritus at Stanford University, who was an early pioneer in the field of computer science. Since 1969, Pratt has made several contributions to foundational areas such as search algorithms, sorting algorithms, and primality testing. More recently, his research has focused on formal modeling of concurrent systems and Chu spaces.
Career
Raised in Australia and educated at Knox Grammar School, where he was dux in 1961, Pratt attended Sydney University, where he completed his masters thesis in 1970, related to what is now known as natural language processing. He then went to the United States, where he completed a Ph.D. thesis at Stanford University in only 20 months under the supervision of advisor Donald Knuth. His thesis focused on analysis of the Shellsort sorting algorithm and sorting networks.
Pratt was an assistant professor at MIT (1972 to 1976) and then associate professor (1976 to 1982). In 1974, working in collaboration with Knuth and James H. Morris, Pratt completed and formalized work he had begun in 1970 as a graduate student at Berkeley; the coauthored result was the Knuth–Morris–Pratt pattern matching algorithm. In 1976, he developed the system of dynamic logic, a modal logic of structured behavior.
He went on sabbatical from MIT to Stanford (1980 to 1981), and was appointed a full professor at Stanford in 1981.
Pratt directed the SUN workstation project at Stanford from 1980 to 1982. He contributed in variou
|
https://en.wikipedia.org/wiki/Digit%20sum
|
In mathematics, the digit sum of a natural number in a given number base is the sum of all its digits. For example, the digit sum of the decimal number would be
Definition
Let be a natural number. We define the digit sum for base , to be the following:
where is one less than the number of digits in the number in base , and
is the value of each digit of the number.
For example, in base 10, the digit sum of 84001 is
For any two bases and for sufficiently large natural numbers
The sum of the base 10 digits of the integers 0, 1, 2, ... is given by in the On-Line Encyclopedia of Integer Sequences. use the generating function of this integer sequence (and of the analogous sequence for binary digit sums) to derive several rapidly converging series with rational and transcendental sums.
Extension to negative integers
The digit sum can be extended to the negative integers by use of a signed-digit representation to represent each integer.
Applications
The concept of a decimal digit sum is closely related to, but not the same as, the digital root, which is the result of repeatedly applying the digit sum operation until the remaining value is only a single digit. The decimal digital root of any non-zero integer will be a number in the range 1 to 9, whereas the digit sum can take any value. Digit sums and digital roots can be used for quick divisibility tests: a natural number is divisible by 3 or 9 if and only if its digit sum (or digital root) is divisible by 3 or 9,
|
https://en.wikipedia.org/wiki/Polydisc
|
In the theory of functions of several complex variables, a branch of mathematics, a polydisc is a Cartesian product of discs.
More specifically, if we denote by the open disc of center z and radius r in the complex plane, then an open polydisc is a set of the form
It can be equivalently written as
One should not confuse the polydisc with the open ball in Cn, which is defined as
Here, the norm is the Euclidean distance in Cn.
When , open balls and open polydiscs are not biholomorphically equivalent, that is, there is no biholomorphic mapping between the two. This was proven by Poincaré in 1907 by showing that their automorphism groups have different dimensions as Lie groups.
When the term bidisc is sometimes used.
A polydisc is an example of logarithmically convex Reinhardt domain.
References
Several complex variables
|
https://en.wikipedia.org/wiki/Andrew%20B.%20Whinston
|
Andrew B. Whinston (born June 3, 1936) is an American economist and computer scientist. He is the Hugh Roy Cullen Centennial Chair in Business Administration, Professor of Information Systems, Computer Science and Economics, and Director of the Center for Research in Electronic Commerce (CREC) in the McCombs School of Business at the University of Texas at Austin.
In the late 1950s, he was Sanxsay Fellow at Princeton University. Whinston finished his PhD from the Carnegie Institute of Technology in 1962, at which time he also received its Alexander Henderson Award for Excellence in Economic Theory. He started work at the Yale University economics department, where he was a member of the Cowles Foundation. He became an associate professor of economics at the University of Virginia in 1964. By 1966 he was a full professor at Purdue University, where he became the university's inaugural Weiler Distinguished Professor of management, economics, and computer science.
He began his contributions to the academic world in 1961 when he published a paper in a law journal on the topic of urban renewal. In 1962 he published his first two papers. The first was in the Journal of Political Economy where he showed how non-cooperative game theory could be applied to issues in microeconomics. In the second paper entitled "A Model of Multi-Period Investment under Uncertainty" which appeared in Management Science he used nonlinear optimization methods to determine optimal portfolios over time.
|
https://en.wikipedia.org/wiki/Thomas%20S.%20Ray
|
Thomas S. Ray is an evolutionary biologist known for his research in tropical biology, digital evolution, and the human mind.
Early life and education
Ray earned his undergraduate degrees in biology and chemistry at Florida State University. He then proceeded to Harvard University, where he received his master's and Doctorate in Biology, specializing in plant behavior.
Career
Ray began his career as a member of the Society of Fellows at the University of Michigan at Ann Arbor and a member of the faculty of the University of Delaware's School of Life and Health Sciences. In 1993 he received a joint appointment in Computer and Information Science at U. Delaware while also being appointed to the External Faculty of the Santa Fe Institute.
In August 1998 he joined the Advanced Telecommunications Research Institute International's Human Information Processing Research Labs Evolutionary Systems Department as an invited researcher before eventually becoming a Professor in the Zoology (later Biology) & Computer Science departments at the University of Oklahoma.
Throughout his career he has studied different disciplines:
Tropical Biology (1974 - 1989) where he focused on foraging behavior among vines primarily located throughout Costa Rica.
Artificial Life (1990 -2001) which delved into digital evolution by natural selection via the Tierra system.
Architecture of the Human Mind (Current) investigating mental disorders, evolvability, consciousness, and molecular ment
|
https://en.wikipedia.org/wiki/Homer%20Jacobson
|
Homer Jacobson is a former chemistry professor at Brooklyn College, New York City.
In the 1950s he illustrated basic self-replication in artificial life with a model train set. A seed "organism" consisting of a "head" and "tail" boxcar could use the simple rules of the system to consistently create new "organisms" identical to itself, so long as there was a random pool of new boxcars to draw from.
In 1955 he published "Information, Reproduction and the Origin of Life," in American Scientist. In 2007, he retracted two passages of this work after realizing that errors in his paper were being misread as evidence for creationism.
Articles
"Virustat, a Device for Continuous Production of Viruses," Applied Microbiology, 14(6): 940–952 (1966 November) with Leslie S. Jacobson.
"The Informational Capacity of the Human Eye," Science 113:292-293 (March 16, 1951).
"The Informational Capacity of the Human Ear," Science 112:143-144 (August 4, 1950).
"The informational content of mechanisms and circuits," Information and Control, 2(3):285-296, September 1959.
"On Models of Reproduction," American Scientist 46(1958):255-284.
"Information, Reproduction and the Origin of Life," American Scientist, p. 125 (January 1955)
Retraction of two passages: Letter to the editor, American Scientist (November–December 2007)
References
21st-century American chemists
Living people
Year of birth missing (living people)
Brooklyn College faculty
Researchers of artificial life
|
https://en.wikipedia.org/wiki/Edward%20F.%20Moore
|
Edward Forrest Moore (November 23, 1925 in Baltimore, Maryland – June 14, 2003 in Madison, Wisconsin) was an American professor of mathematics and computer science, the inventor of the Moore finite state machine, and an early pioneer of artificial life.
Biography
Moore received a B.S. in chemistry from the Virginia Polytechnic Institute in Blacksburg, Virginia in 1947 and a Ph.D. in Mathematics from Brown University in Providence, Rhode Island in June 1950. He worked at the University of Illinois at Urbana–Champaign from 1950 to 1952 and was a visiting professor at MIT and visiting lecturer at Harvard University simultaneously in 1961-1962. He worked at Bell Labs from 1952 to 1966. After that, he was a professor at the University of Wisconsin–Madison from 1966 until he retired in 1985.
He married Elinor Constance Martin and they had three children.
Scientific work
He was the first to use the type of finite state machine (FSM) that is commonly used today, the Moore FSM. With Claude Shannon he did seminal work on computability theory and built reliable circuits using less reliable relays. He also spent a great deal of his later years on a fruitless effort to solve the Four Color Theorem.
With John Myhill, Moore proved the Garden of Eden theorem characterizing the cellular automaton rules that have patterns with no predecessor. He is also the namesake of the Moore neighborhood for cellular automata, used by Conway's Game of Life, and was the first to publish on the firing
|
https://en.wikipedia.org/wiki/Coloring
|
Coloring or colouring may refer to:
Color, or the act of changing the color of an object
Coloring, the act of adding color to the pages of a coloring book
Coloring, the act of adding color to comic book pages, where the person's job title is Colorist
Graph coloring, in mathematics
Hair coloring
Food coloring
Hand-colouring of photographs
Map coloring
See also
Color code (disambiguation)
Color grading
|
https://en.wikipedia.org/wiki/George%20Klein%20%28inventor%29
|
George Johann Klein, (August 15, 1904 – November 4, 1992) was a Canadian inventor who is often called the most productive inventor in Canada in the 20th century. Although he struggled as a high school student, he eventually graduated from the University of Toronto in Mechanical Engineering. His inventions include key contributions to the first electric wheelchairs for quadriplegics, the first microsurgical staple gun, the ZEEP nuclear reactor which was the precursor to the CANDU reactor, the international system for classifying ground-cover snow, aircraft skis, the Weasel all-terrain vehicle, the STEM antenna for the space program, and the Canadarm.
Klein worked for forty years as a mechanical engineer at the National Research Council of Canada laboratories in Ottawa (1929–1969).
In 1968, he was made an Officer of the Order of Canada. In 1995, he was inducted to the Canadian Science and Engineering Hall of Fame.
References
Notes
Bibliography
Bourgeois-Doyle, Richard I. George J. Klein: The Great Inventor. Ottawa: NRC Research Press, 2004. .
External links
George J. Klein at Canadian Science and Technology Museum Hall of Fame
Canadian Science and Technology Museum Virtual Program at Canadian Science and Technology Museum
George J. Klein at CDC
NRC Archives Photos - George Klein Wheel Chair
1904 births
1992 deaths
20th-century Canadian inventors
People from Hamilton, Ontario
Canadian Members of the Order of the British Empire
Officers of the Order of Ca
|
https://en.wikipedia.org/wiki/Direct%20comparison%20test
|
In mathematics, the comparison test, sometimes called the direct comparison test to distinguish it from similar related tests (especially the limit comparison test), provides a way of deducing the convergence or divergence of an infinite series or an improper integral. In both cases, the test works by comparing the given series or integral to one whose convergence properties are known.
For series
In calculus, the comparison test for series typically consists of a pair of statements about infinite series with non-negative (real-valued) terms:
If the infinite series converges and for all sufficiently large n (that is, for all for some fixed value N), then the infinite series also converges.
If the infinite series diverges and for all sufficiently large n, then the infinite series also diverges.
Note that the series having larger terms is sometimes said to dominate (or eventually dominate) the series with smaller terms.
Alternatively, the test may be stated in terms of absolute convergence, in which case it also applies to series with complex terms:
If the infinite series is absolutely convergent and for all sufficiently large n, then the infinite series is also absolutely convergent.
If the infinite series is not absolutely convergent and for all sufficiently large n, then the infinite series is also not absolutely convergent.
Note that in this last statement, the series could still be conditionally convergent; for real-valued series, this could happen if
|
https://en.wikipedia.org/wiki/NSA%20Suite%20B%20Cryptography
|
NSA Suite B Cryptography was a set of cryptographic algorithms promulgated by the National Security Agency as part of its Cryptographic Modernization Program. It was to serve as an interoperable cryptographic base for both unclassified information and most classified information.
Suite B was announced on 16 February 2005. A corresponding set of unpublished algorithms, Suite A, is "used in applications where Suite B may not be appropriate. Both Suite A and Suite B can be used to protect foreign releasable information, US-Only information, and Sensitive Compartmented Information (SCI)."
In 2018, NSA replaced Suite B with the Commercial National Security Algorithm Suite (CNSA).
Suite B's components were:
Advanced Encryption Standard (AES) with key sizes of 128 and 256 bits. For traffic flow, AES should be used with either the Counter Mode (CTR) for low bandwidth traffic or the Galois/Counter Mode (GCM) mode of operation for high bandwidth traffic (see Block cipher modes of operation) symmetric encryption
Elliptic Curve Digital Signature Algorithm (ECDSA) digital signatures
Elliptic Curve Diffie–Hellman (ECDH) key agreement
Secure Hash Algorithm 2 (SHA-256 and SHA-384) message digest
General information
NIST, Recommendation for Pair-Wise Key Establishment Schemes Using Discrete Logarithm Cryptography, Special Publication 800-56A
Suite B Cryptography Standards
, Suite B Certificate and Certificate Revocation List (CRL) Profile
, Suite B Cryptographic Suites for Secure
|
https://en.wikipedia.org/wiki/David%20Berlinski
|
David Berlinski (born 1942) is an American author who has written books about mathematics and the history of science as well as fiction. An opponent of evolution, he is a senior fellow of the Discovery Institute's Center for Science and Culture, an organization which promotes the pseudoscience of intelligent design.
Early life
David Berlinski was born in the United States in 1942 to German-born Jewish refugees who had emigrated to New York City after escaping from France while the Vichy government was collaborating with the Germans. His father was Herman Berlinski, a composer, organist, pianist, musicologist and choir conductor, and his mother was Sina Berlinski (née Goldfein), a pianist, piano teacher and voice coach. Both were born and raised in Leipzig, where they studied at the Conservatory, before fleeing to Paris, where they were married and undertook further studies. German was David Berlinski's first spoken language. He earned his BA from Columbia University and PhD in philosophy from Princeton University.
Academic career
After his PhD, Berlinski was a research assistant in the Department of Biology at Columbia University. He has taught philosophy, mathematics and English at Stanford University, Rutgers, the City University of New York and the Université de Paris. He was a research fellow at the International Institute for Applied Systems Analysis (IIASA) in Austria and the Institut des Hautes Études Scientifiques (IHES) in France.
Author
Mathematics and biology
|
https://en.wikipedia.org/wiki/Douglas%20Daft
|
Douglas Neville Daft (born 20 March 1943 in Cessnock, New South Wales) is an Australian businessman.
He graduated from the University of New England in Armidale, New South Wales in 1963 with a Bachelor of Arts degree, majoring in Mathematics. While at the University of New England he lived at Robb College. During the 1960s he taught science at Vaucluse Boys' High School in Sydney. In 1970 he graduated from the University of New South Wales with a Diploma of Admin. He was CEO of Coca-Cola (2000–2004). In 2005, he was appointed Companion of the Order of Australia (AC) for his leadership in the global business community.
References
External links
1943 births
Australian businesspeople
Coca-Cola people
Living people
Directors of Walmart
Companions of the Order of Australia
University of New South Wales alumni
People from Cessnock, New South Wales
Rothschild & Co people
|
https://en.wikipedia.org/wiki/Mittag-Leffler%20function
|
In mathematics, the Mittag-Leffler function is a special function, a complex function which depends on two complex parameters and . It may be defined by the following series when the real part of is strictly positive:
where is the gamma function. When , it is abbreviated as .
For , the series above equals the Taylor expansion of the geometric series and consequently .
In the case and are real and positive, the series converges for all values of the argument , so the Mittag-Leffler function is an entire function. This function is named after Gösta Mittag-Leffler. This class of functions are important in the theory of the fractional calculus.
For , the Mittag-Leffler function is an entire function of order , and is in some sense the simplest entire function of its order.
The Mittag-Leffler function satisfies the recurrence property (Theorem 5.1 of )
from which the following Poincaré asymptotic expansion holds : for and real such that
then for all , we can show the following asymptotic expansions (Section 6. of ):
-as :
,
-and as :
,
where we used the notation .
Special cases
For we find: (Section 2 of )
Error function:
The sum of a geometric progression:
Exponential function:
Hyperbolic cosine:
For , we have
For , the integral
gives, respectively: , , .
Mittag-Leffler's integral representation
The integral representation of the Mittag-Leffler function is (Section 6 of )
where the contour starts and ends at and circles around the singularitie
|
https://en.wikipedia.org/wiki/Weierstrass%20functions
|
In mathematics, the Weierstrass functions are special functions of a complex variable that are auxiliary to the Weierstrass elliptic function. They are named for Karl Weierstrass. The relation between the sigma, zeta, and functions is analogous to that between the sine, cotangent, and squared cosecant functions: the logarithmic derivative of the sine is the cotangent, whose derivative is negative the squared cosecant.
Weierstrass sigma function
The Weierstrass sigma function associated to a two-dimensional lattice is defined to be the product
where denotes or are a fundamental pair of periods.
Through careful manipulation of the Weierstrass factorization theorem as it relates also to the sine function, another potentially more manageable infinite product definition is
for any with and where we have used the notation (see zeta function below).
Weierstrass zeta function
The Weierstrass zeta function is defined by the sum
The Weierstrass zeta function is the logarithmic derivative of the sigma-function. The zeta function can be rewritten as:
where is the Eisenstein series of weight 2k + 2.
The derivative of the zeta function is , where is the Weierstrass elliptic function.
The Weierstrass zeta function should not be confused with the Riemann zeta function in number theory.
Weierstrass eta function
The Weierstrass eta function is defined to be
and any w in the lattice
This is well-defined, i.e. only depends on the lattice vector w. The Weierstrass eta f
|
https://en.wikipedia.org/wiki/John%20B.%20Goodenough
|
John Bannister Goodenough ( ; July 25, 1922 – June 25, 2023) was an American materials scientist, a solid-state physicist, and a Nobel laureate in chemistry. From 1996 he was a professor of Mechanical, Materials Science, and Electrical Engineering at the University of Texas at Austin. He is credited with
identifying the Goodenough–Kanamori rules of the sign of the magnetic superexchange in materials, with developing materials for computer random-access memory and with inventing cathode materials for lithium-ion batteries.
Goodenough was born in Jena, German Reich (Weimar Republic), to American parents. During and after graduating from Yale University, Goodenough served as a U.S. military meteorologist in World War II. He went on to obtain his Ph.D. in physics at the University of Chicago, became a researcher at MIT Lincoln Laboratory, and later the head of the Inorganic Chemistry Laboratory at the University of Oxford.
Goodenough was awarded the National Medal of Science, the Copley Medal, the Fermi Award, the Draper Prize, and the Japan Prize. The John B. Goodenough Award in materials science is named for him. In 2019, he was awarded the Nobel Prize in Chemistry alongside M. Stanley Whittingham and Akira Yoshino, and, at 97 years old, became the oldest Nobel laureate in history. From August 27, 2021, until his death, he was the oldest living Nobel Prize laureate.
Personal life and education
John Goodenough was born in Jena, Germany, on July 25, 1922, to American paren
|
https://en.wikipedia.org/wiki/Memory%20cell
|
Memory cell may refer to:
Biology
Memory cells (motor cortex), found in the primary motor cortex (M1), a region located in the posterior portion of the frontal lobe of the brain.
Memory B cell, an antibody producing cell
Memory T cell, an infection fighting cell
Computing
Memory cell (computing), a building block of computer memory and data storage
|
https://en.wikipedia.org/wiki/Solubility%20pump
|
In oceanic biogeochemistry, the solubility pump is a physico-chemical process that transports carbon as dissolved inorganic carbon (DIC) from the ocean's surface to its interior.
Overview
The solubility pump is driven by the coincidence of two processes in the ocean :
The solubility of carbon dioxide is a strong inverse function of seawater temperature (i.e. solubility is greater in cooler water)
The thermohaline circulation is driven by the formation of deep water at high latitudes where seawater is usually cooler and denser
Since deep water (that is, seawater in the ocean's interior) is formed under the same surface conditions that promote carbon dioxide solubility, it contains a higher concentration of dissolved inorganic carbon than might be expected from average surface concentrations. Consequently, these two processes act together to pump carbon from the atmosphere into the ocean's interior.
One consequence of this is that when deep water upwells in warmer, equatorial latitudes, it strongly outgasses carbon dioxide to the atmosphere because of the reduced solubility of the gas.
The solubility pump has a biological counterpart known as the biological pump. For an overview of both pumps, see Raven & Falkowski (1999).
Carbon dioxide solubility
Carbon dioxide, like other gases, is soluble in water. However, unlike many other gases (oxygen for instance), it reacts with water and forms a balance of several ionic and non-ionic species (collectively known as dissol
|
https://en.wikipedia.org/wiki/C.%20N.%20R.%20Rao
|
Chintamani Nagesa Ramachandra Rao, (born 30 June 1934), is an Indian chemist who has worked mainly in solid-state and structural chemistry. He has honorary doctorates from 84 universities from around the world and has authored around 1,800 research publications and 56 books. He is described as a scientist who had won all possible awards in his field except the Nobel Prize.
A precocious child, Rao completed BSc from Mysore University at age seventeen, and MSc from Banaras Hindu University at age nineteen. He earned a PhD from Purdue University at the age of twenty-four. He was the youngest lecturer when he joined the Indian Institute of Science in 1959. After a transfer to Indian Institute of Technology Kanpur, he returned to IISc, eventually becoming its Director from 1984 to 1994. He was chair of the Scientific Advisory Council to the Prime Minister of India from 1985 to 1989 and from 2005 to 2014. He founded and works in Jawaharlal Nehru Centre for Advanced Scientific Research and International Centre for Materials Science.
Rao received most important scientific awards and honours including the Marlow Medal, Shanti Swarup Bhatnagar Prize for Science and Technology, Hughes Medal, India Science Award, Dan David Prize, Royal Medal, Von Hippel Award, and ENI award. He also received Padma Shri and Padma Vibhushan from the Government of India. On 16 November 2013, the Government of India selected him for Bharat Ratna, the highest civilian award in India, making him the third
|
https://en.wikipedia.org/wiki/Meanings%20of%20minor%20planet%20names%3A%2080001%E2%80%9381000
|
80001–80100
|-id=008
| 80008 Danielarhodes || || Daniela Rhodes (born 1946) is an Italian chemical engineer working in scientific research. She was elected Member and Chair of the European Molecular Biology Organization Council and since 2007 has been a Fellow of the Royal Society. ||
|}
80101–80200
|-id=135
| 80135 Zanzanini || || Giuseppe Zan Zanini (1794–1869) lived in Val Bavona and Val Foiòi in Ticino, Switzerland. His history is a symbol of the hard life and fragile existence supported by the valley inhabitants of Ticino in 1800. ||
|-id=179
| 80179 Václavknoll || 1999 VK || (1964–2010) was a Czech astronomer and promoter and popularizer of astronomy, natural sciences and technologies in the Czech city and region of Pardubice and particularly for young people. Since 1994 he has been the chief of the Pardubice's observatory of Baron Arthur Kraus. ||
|-id=180
| 80180 Elko || 1999 VS || The city of Elko in Nevada, United States, home of the National Basque Festival and the Cowboy Poetry Gathering ||
|-id=184
| 80184 Hekigoto || || Hekigoto Kawahigashi (1873–1937), was a Japanese Haiku poet. He started to compose Haiku at the age of sixteen, inspired by the highly renowned Haiku poet Shiki Masaoka. He later became absorbed in free style Haiku and co-founded the avant-garde Haiku journal So-un. ||
|}
80201–80300
|-bgcolor=#f2f2f2
| colspan=4 align=center |
|}
80301–80400
|-bgcolor=#f2f2f2
| colspan=4 align=center |
|}
80401–80500
|-id=451
| 80451 A
|
https://en.wikipedia.org/wiki/Bart%20Kosko
|
Bart Andrew Kosko (born February 7, 1960) is a writer and professor of electrical engineering and law at the University of Southern California (USC). He is a researcher and popularizer of fuzzy logic, neural networks, and noise, and the author of several trade books and textbooks on these and related subjects of machine intelligence. He was awarded the 2022 Donald O. Hebb Award for neural learning by the International Neural Network Society.
Personal background
Kosko holds bachelor's degrees in philosophy and in economics from USC (1982), a master's degree in applied mathematics from UC San Diego (1983), a PhD in electrical engineering from UC Irvine (1987) under Allen Stubberud, and a J.D. from Concord Law School. He is an attorney licensed in California and federal court, and worked part-time as a law clerk for the Los Angeles District Attorney's Office.
Kosko is a political and religious skeptic. He is a contributing editor of the libertarian periodical Liberty, where he has published essays on "Palestinian vouchers".
Writing
Kosko's most popular book to date was the international best-seller Fuzzy Thinking, about man and machines thinking in shades of gray, and his most recent book was Noise. He has also published short fiction and the cyber-thriller novel Nanotime, about a possible World War III that takes place in two days of the year 2030. The novel's title coins the term "nanotime" to describe the time speed-up that occurs when fast computer chips, rather than slow
|
https://en.wikipedia.org/wiki/Dancing%20tree
|
In computer science, a dancing tree is a tree data structure similar to B+ trees. It was invented by Hans Reiser, for use by the Reiser4 file system. As opposed to self-balancing binary search trees that attempt to keep their nodes balanced at all times, dancing trees only balance their nodes when flushing data to a disk (either because of memory constraints or because a transaction has completed).
The idea behind this is to speed up file system operations by delaying optimization of the tree and only writing to disk when necessary, as writing to disk is thousands of times slower than writing to memory. Also, because this optimization is done less often than with other tree data structures, the optimization can be more extensive.
In some sense, this can be considered to be a self-balancing binary search tree that is optimized for storage on a slow medium, in that the on-disc form will always be balanced but will get no mid-transaction writes; doing so eases the difficulty of adding and removing nodes during a transaction. Instead, these slow rebalancing operations are performed at the same time as the much slower write to the storage medium.
However, a negative side effect of this behavior manifests in cases of unexpected shutdown, incomplete data writes, and other occurrences that may prevent the final balanced transaction from completing. In general, dancing trees pose greater difficulty than conventional trees for data recovery from incomplete transactions, though th
|
https://en.wikipedia.org/wiki/Fundamental%20pair%20of%20periods
|
In mathematics, a fundamental pair of periods is an ordered pair of complex numbers that defines a lattice in the complex plane. This type of lattice is the underlying object with which elliptic functions and modular forms are defined.
Definition
A fundamental pair of periods is a pair of complex numbers such that their ratio is not real. If considered as vectors in , the two are not collinear. The lattice generated by and is
This lattice is also sometimes denoted as to make clear that it depends on and It is also sometimes denoted by or or simply by The two generators and are called the lattice basis. The parallelogram with vertices is called the fundamental parallelogram.
While a fundamental pair generates a lattice, a lattice does not have any unique fundamental pair; in fact, an infinite number of fundamental pairs correspond to the same lattice.
Algebraic properties
A number of properties, listed below, can be seen.
Equivalence
Two pairs of complex numbers and are called equivalent if they generate the same lattice: that is, if
No interior points
The fundamental parallelogram contains no further lattice points in its interior or boundary. Conversely, any pair of lattice points with this property constitute a fundamental pair, and furthermore, they generate the same lattice.
Modular symmetry
Two pairs and are equivalent if and only if there exists a matrix with integer entries and and determinant such that
that is, so that
This matrix b
|
https://en.wikipedia.org/wiki/Pinwheel%20%28cryptography%29
|
In cryptography, a pinwheel was a device for producing a short pseudorandom sequence of bits (determined by the machine's initial settings), as a component in a cipher machine. A pinwheel consisted of a rotating wheel with a certain number of positions on its periphery. Each position had a "pin", "cam" or "lug" which could be either "set" or "unset". As the wheel rotated, each of these pins would in turn affect other parts of the machine, producing a series of "on" or "off" pulses which would repeat after one full rotation of the wheel. If the machine contained more than one wheel, usually their periods would be relatively prime to maximize the combined period. Pinwheels might be turned through a purely mechanical action (as in the M-209) or electromechanically (as in the Lorenz SZ 40/42).
Development
The Swedish engineer Boris Caesar Wilhelm Hagelin is credited with having invented the first pinwheel device in 1925. He developed the machine while employed by Emanuel Nobel to oversee the Nobel interests in Aktiebolaget Cryptograph. He was the nephew of the founder of the Nobel Prize. The device was later introduced in France and Hagelin was awarded the French order of merit, Legion d'Honneur, for his work. One of the earliest cipher machines that Hagaelin developed was the C-38 and was later improved into the more portable Hagelin m-209. The M-209 is composed of a set of pinwheels and a rotating cage.
Other cipher machines which used pinwheels include the C-52, the CD-57 a
|
https://en.wikipedia.org/wiki/Victor%20Ewald
|
Victor Vladímirovich Ewald (or Ėval′d) (; 27 November 1860 – 16 April 1935), was a Russian engineer, architect, and composer of music, mainly for conical brass instruments.
Biography
Victor Ewald was born in Saint Petersburg and died in Leningrad. Ewald was a professor of Civil Engineering in St. Petersburg, and was also the cellist with the Beliaeff Quartet for sixteen years. This quartet was the most influential ensemble in St. Petersburg in the late 19th century, introducing much of the standard quartet literature to Russian concertgoers. He also collected and published Russian folk songs much like other composers of his time.
Ewald’s professional life, like that of many of his musical contemporaries, was in an entirely different field; that of a civil engineer. He excelled in this field, being appointed in 1900 as professor and manager of the Faculty of Construction Materials at the St. Petersburg Institute of Civil Engineers. From 1910 to 1924, Ewald served as editor of the architectural journal Zodchii. From 1922 to 1932, he chaired the Petrograd Society of Architects. An obituary signed by his fellow professors of the I.C.E. makes mention of a profound heritage in the development of materials production for construction resulting from Ewald’s work, and suggests that “…an entire industry for the production of brick and cement manufacturing is beholden to him”. Brass players however, are indebted to him for something very different – a series of quintets which have b
|
https://en.wikipedia.org/wiki/1585%20in%20science
|
The year 1585 in science and technology included many events, some of which are listed here.
Exploration
August 8 – English explorer John Davis enters Cumberland Sound in Baffin Island in his quest for the Northwest Passage.
Mathematics
John Blagrave publishes The Mathematical Jewel, showing the making and most excellent use of a singular instrument so called, in that it performeth with wonderful dexterity whatever is to be done either by quadrant, ship, circle, cylinder, ring, dial, horoscope, astrolabe, sphere, globe or any such like heretofore devised.
Giordano Bruno uses Fabrizio Mordente "proportional eight-pointed compass" to refute Aristotle's hypothesis on the incommensurability of infinitesimals, thus confirming the existence of the "minimum" which lays the basis of his own atomic theory. Bruno publishes his proofs as Figuratio Aristotelici Physici auditus.
Simon Stevin publishes De Thiende, introducing a form of decimal fraction.
Medicine
Samuel Eisenmenger publishes Cyclopaedia Paracelsica Christiana. Three books of this were the origin and tradition of the liberal arts, also of the physiognomy, above miracles and weather in Brussels.
Other events
The University of Franeker was founded in the United Provinces of the Netherlands.
The University of Graz was founded by Charles II, Archduke of Austria.
Births
February 12 - Caspar Bartholin the Elder, Swedish polymath (died 1629)
November 1 - Jan Brożek, Polish polymath (died 1652)
Deaths
March 10 – Remb
|
https://en.wikipedia.org/wiki/NH4
|
NH4 or NH 4 or NH-4 may refer to:
Ammonium, the cation in chemistry
National Highway 4 (India), new numbering for a National Highway in India
National Highway 4 (India, old numbering), a major National Highway in western and southern India
New Hampshire Route 4, a short state highway located in eastern Strafford County, New Hampshire, United States
|
https://en.wikipedia.org/wiki/Postulates%20of%20special%20relativity
|
In physics, Albert Einstein derived the theory of special relativity in 1905 from principle now called the postulates of special relativity. Einstein's formulation is said to only require two postulates, though his derivation implies a few more assumptions.
The idea that special relativity depended only on two postulates, both of which seemed to be follow from the theory and experiment of the day, was one of the most compelling arguments for the correctness of the theory (Einstein 1912: "This theory is correct to the extent to which the two principles upon which it is based are correct. Since these seem to be correct to a great extent, ...")
Postulates of special relativity
1. First postulate (principle of relativity)
The laws of physics take the same form in all inertial frames of reference.
2. Second postulate (invariance of c)
As measured in any inertial frame of reference, light is always propagated in empty space with a definite velocity c that is independent of the state of motion of the emitting body. Or: the speed of light in free space has the same value c in all inertial frames of reference.
The two-postulate basis for special relativity is the one historically used by Einstein, and it is sometimes the starting point today. As Einstein himself later acknowledged, the derivation of the Lorentz transformation tacitly makes use of some additional assumptions, including spatial homogeneity, isotropy, and memorylessness. Also Hermann Minkowski implicitly used
|
https://en.wikipedia.org/wiki/Tufts%20University%20School%20of%20Engineering
|
The School of Engineering is one of the ten schools that comprise Tufts University. The school offers undergraduate and graduate degrees in several engineering disciplines and computer science fields. Along with the School of Arts and Sciences (A&S) and the Fletcher School of Law and Diplomacy, the School of Engineering is located on the university's main campus in Medford and Somerville, Massachusetts. Currently, the engineering school enrolls more than 800 full-time undergraduates and 600 graduate students. The school employs over 100 full-time and part-time faculty members.
History
Engineering instruction began at Tufts College in academic year 1865 - 1866, with the introduction of a three-year degree program in civil engineering. Students in this program received the degree of civil engineer. In 1890, the Department of Electrical Engineering was created, and in academic year 1892-1893, the course of study was extended to four years. With the advent of the four-year program the degrees granted were bachelor of civil or electrical engineering. Tufts College added the Department of Mechanical Engineering and the Department of Chemical Engineering in 1894 and 1898, respectively. In 1898, the trustees voted to formally establish an undergraduate College of Engineering with Gardner C. Anthony as the first dean. As part of an administrative reorganization in 1904, the College of Engineering became part of the new Faculty of Arts and Sciences, along with the School (later the Co
|
https://en.wikipedia.org/wiki/Alex%20Grossmann
|
Alexander Grossmann (5 August 1930 – 12 February 2019) was a French-American physicist of Croatian origin.
He travelled to the United States in 1955, working in the physics departments of the Institute for Advanced Study (IAS), Princeton, Brandeis University, and the Courant Institute, NYU, then again at the IAS until 1963.
After one year at the Institut des Hautes Études Scientifiques (IHES) in Bures-sur-Yvette, France, he joined the "Centre de Physique Théorique de Marseille" (the CPT) as it was being created in 1966, at the request of Daniel Kastler. He then becomes research supervisor at the CNRS.
At the Université de la Méditerranée Aix-Marseille II in Luminy campus he did pioneering work on wavelet analysis with Jean Morlet in 1984. This in effect showed this identity's applicability to signal analysis.
In 1993, he became involved in genomic research as part of a group formed in Gif-sur-Yvette. He worked in this area with what eventually became the Laboratoire de Mathématique & Modélisation d’Evry until 2014.
Grossmann died on 12 February 2019.
Publications
Description of the Extended Tube (1960)
Algebraic Characterization of the TCP Operation (1960)
Schrödinger Scattering Amplitude (I) (1961)
Schrödinger Scattering Amplitude (II) (1961)
Schrödinger Scattering Amplitude (III) (1962)
Nested Hilbert Spaces in Quantum Mechanics (I) (1964)
Fields at a Point (1967)
A class of explicitly soluble, local, many‐center Hamiltonians for one‐particle quantum mechan
|
https://en.wikipedia.org/wiki/Vi%C3%A8te%27s%20formula
|
In mathematics, Viète's formula is the following infinite product of nested radicals representing twice the reciprocal of the mathematical constant :
It can also be represented as:
The formula is named after François Viète, who published it in 1593. As the first formula of European mathematics to represent an infinite process, it can be given a rigorous meaning as a limit expression, and marks the beginning of mathematical analysis. It has linear convergence, and can be used for calculations of , but other methods before and since have led to greater accuracy. It has also been used in calculations of the behavior of systems of springs and masses, and as a motivating example for the concept of statistical independence.
The formula can be derived as a telescoping product of either the areas or perimeters of nested polygons converging to a circle. Alternatively, repeated use of the half-angle formula from trigonometry leads to a generalized formula, discovered by Leonhard Euler, that has Viète's formula as a special case. Many similar formulas involving nested roots or infinite products are now known.
Significance
François Viète (1540–1603) was a French lawyer, privy councillor to two French kings, and amateur mathematician. He published this formula in 1593 in his work Variorum de rebus mathematicis responsorum, liber VIII. At this time, methods for approximating to (in principle) arbitrary accuracy had long been known. Viète's own method can be interpreted as a variation
|
https://en.wikipedia.org/wiki/Vortex%20shedding
|
In fluid dynamics, vortex shedding is an oscillating flow that takes place when a fluid such as air or water flows past a bluff (as opposed to streamlined) body at certain velocities, depending on the size and shape of the body. In this flow, vortices are created at the back of the body and detach periodically from either side of the body forming a Kármán vortex street. The fluid flow past the object creates alternating low-pressure vortices on the downstream side of the object. The object will tend to move toward the low-pressure zone.
If the bluff structure is not mounted rigidly and the frequency of vortex shedding matches the resonance frequency of the structure, then the structure can begin to resonate, vibrating with harmonic oscillations driven by the energy of the flow. This vibration is the cause for overhead power line wires humming in the wind, and for the fluttering of automobile whip radio antennas at some speeds. Tall chimneys constructed of thin-walled steel tubes can be sufficiently flexible that, in air flow with a speed in the critical range, vortex shedding can drive the chimney into violent oscillations that can damage or destroy the chimney.
Vortex shedding was one of the causes proposed for the failure of the original Tacoma Narrows Bridge (Galloping Gertie) in 1940, but was rejected because the frequency of the vortex shedding did not match that of the bridge. The bridge actually failed by aeroelastic flutter.
A thrill ride, "VertiGo" at Cedar Point
|
https://en.wikipedia.org/wiki/Energy%20density
|
In physics, energy density is the amount of energy stored in a given system or region of space per unit volume. It is sometimes confused with energy per unit mass which is properly called specific energy or .
Often only the useful or extractable energy is measured, which is to say that inaccessible energy (such as rest mass energy) is ignored. In cosmological and other general relativistic contexts, however, the energy densities considered are those that correspond to the elements of the stress-energy tensor and therefore do include mass energy as well as energy densities associated with pressure.
Energy per unit volume has the same physical units as pressure and in many situations is synonymous. For example, the energy density of a magnetic field may be expressed as and behaves like a physical pressure. Likewise, the energy required to compress a gas to a certain volume may be determined by multiplying the difference between the gas pressure and the external pressure by the change in volume. A pressure gradient describes the potential to perform work on the surroundings by converting internal energy to work until equilibrium is reached.
Overview
There are different types of energy stored in materials, and it takes a particular type of reaction to release each type of energy. In order of the typical magnitude of the energy released, these types of reactions are: nuclear, chemical, electrochemical, and electrical.
Nuclear reactions take place in stars and nuclear power pl
|
https://en.wikipedia.org/wiki/Walter%20Lewin
|
Walter Hendrik Gustav Lewin (The Hague, January 29, 1936) is a Dutch astrophysicist and retired professor of physics at the Massachusetts Institute of Technology. Lewin earned his doctorate in nuclear physics in 1965 at the Delft University of Technology and was a member of MIT's physics faculty for 43 years beginning in 1966 until his retirement in 2009.
Lewin's contributions in astrophysics include the first discovery of a rotating neutron star through all-sky balloon surveys and research in X-ray detection in investigations through satellites and observatories. Lewin has received awards for teaching and is known for his lectures on physics and their publication online via YouTube, MIT OpenCourseWare and edX.
In December 2014, MIT revoked Lewin's Professor Emeritus title after an MIT investigation determined that Lewin had violated university policy by sexually harassing an online student in a MITx course he taught in fall 2013.
Early life and education
Lewin was born to Walter Simon Lewin and Pieternella Johanna van der Tang in 1936 in The Hague, Netherlands. He was a child when Nazi Germany occupied The Netherlands during World War II. His paternal grandparents Gustav and Emma Lewin, who were Jewish, died in Auschwitz in 1942. To protect the family, Lewin’s father — who was Jewish, unlike his mother — decided one day to simply leave without telling anyone. His mother was left to raise the children and run a small school she and her husband had started together. After t
|
https://en.wikipedia.org/wiki/Oscar%20Allen
|
Oscar Allen may refer to:
Oscar Allen (footballer) (born 1999), Australian rules footballer for the West Coast Eagles
Oscar K. Allen (1882–1936), 42nd governor of Louisiana
Oscar Dana Allen (1836–1913), American professor of chemistry
|
https://en.wikipedia.org/wiki/Reinhold%20Baer
|
Reinhold Baer (22 July 1902 – 22 October 1979) was a German mathematician, known for his work in algebra. He introduced injective modules in 1940. He is the eponym of Baer rings and Baer groups.
Biography
Baer studied mechanical engineering for a year at Leibniz University Hannover. He then went to study philosophy at Freiburg in 1921. While he was at Göttingen in 1922 he was influenced by Emmy Noether and Hellmuth Kneser. In 1924 he won a scholarship for specially gifted students. Baer wrote up his doctoral dissertation and it was published in Crelle's Journal in 1927.
Baer accepted a post at Halle in 1928. There, he published Ernst Steinitz's "Algebraische Theorie der Körper" with Helmut Hasse, first published in Crelle's Journal in 1910.
While Baer was with his wife in Austria, Adolf Hitler and the Nazis came into power. Both of Baer's parents were Jewish, and he was for this reason informed that his services at Halle were no longer required. Louis Mordell invited him to go to Manchester and Baer accepted.
Baer stayed at Princeton University and was a visiting scholar at the nearby Institute for Advanced Study from 1935 to 1937. For a short while he lived in North Carolina. From 1938 to 1956 he worked at the University of Illinois at Urbana-Champaign. He returned to Germany in 1956.
According to biographer K. W. Gruenberg,
The rapid development of lattice theory in the mid-thirties suggested that projective geometry should be viewed as a special kind of lattice, the
|
https://en.wikipedia.org/wiki/L%C3%A9on%20Brillouin
|
Léon Nicolas Brillouin (; August 7, 1889 – October 4, 1969) was a French physicist. He made contributions to quantum mechanics, radio wave propagation in the atmosphere, solid-state physics, and information theory.
Early life
Brillouin was born in Sèvres, near Paris, France. His father, Marcel Brillouin, grandfather, Éleuthère Mascart, and great-grandfather, Charles Briot, were physicists as well.
Education
From 1908 to 1912, Brillouin studied physics at the École Normale Supérieure, in Paris. From 1911 he studied under Jean Perrin until he left for the Ludwig Maximilian University of Munich (LMU), in 1912. At LMU, he studied theoretical physics with Arnold Sommerfeld. Just a few months before Brillouin's arrival at LMU, Max von Laue had conducted his experiment showing X-ray diffraction in a crystal lattice. In 1913, he went back to France to study at the University of Paris and it was in this year that Niels Bohr submitted his first paper on the Bohr model of the hydrogen atom. From 1914 until 1919, during World War I, he served in the military, developing the valve amplifier with G. A. Beauvais. At the conclusion of the war, he returned to the University of Paris to continue his studies with Paul Langevin, and was awarded his Docteur ès science in 1920. Brillouin's thesis jury was composed of Langevin, Marie Curie, and Jean Perrin and his thesis topic was on the quantum theory of solids. In his thesis, he proposed an equation of state based on the atomic vibrations (
|
https://en.wikipedia.org/wiki/Index%20of%20genetics%20articles
|
Genetics (from Ancient Greek , “genite” and that from , “origin”), a discipline of biology, is the science of heredity and variation in living organisms.
Articles (arranged alphabetically) related to genetics include:
#
A
B
C
D
E
F
G
H
I
J
K
L
M
N
O
P
Q
R
S
T
U
V
W
X
Y
Z
References
See also
List of genetics research organizations
List of geneticists & biochemists
Articles
Genetics-related topics
Biotechnology
|
https://en.wikipedia.org/wiki/138%20%28number%29
|
138 (one hundred [and] thirty-eight) is the natural number following 137 and preceding 139.
In mathematics
138 is a sphenic number, and the smallest product of three primes such that in base 10, the third prime is a concatenation of the other two: . It is also a one-step palindrome in decimal (138 + 831 = 969).
138 has eight total divisors that generate an arithmetic mean of 36, which is the eighth triangular number. While the sum of the digits of 138 is 12, the product of its digits is 24.
138 is an Ulam number, the thirty-first abundant number, and a primitive (square-free) congruent number. It is the third 47-gonal number.
As an interprime, 138 lies between the eleventh pair of twin primes (137, 139), respectively the 33rd and 34th prime numbers.
It is the sum of two consecutive primes (67 + 71), and the sum of four consecutive primes (29 + 31 + 37 + 41).
There are a total of 44 numbers that are relatively prime with 138 (and up to), while 22 is its reduced totient.
138 is the denominator of the twenty-second Bernoulli number (whose respective numerator, is 854513).
A magic sum of 138 is generated inside four magic circles that features the first thirty-three non-zero integers, with a 9 in the center (first constructed by Yang Hui).
The simplest Catalan solid, the triakis tetrahedron, produces 138 stellations (depending on rules chosen), 44 of which are fully symmetric and 94 of which are enantiomorphs.
Using two radii to divide a circle according to the
|
https://en.wikipedia.org/wiki/PSPLab
|
The Perceptual Signal Processing Lab, or PSPLab, is an audio research lab of National Chiao Tung University. It is located in Hsinchu, Taiwan, and focuses on researching better perceptual signal processing techniques, particularly in regard to DSP, Perception, and Software.
Current areas of research in PSPLab include:
Multi Channel Audio Compression
MP3 codec, MPEG-2/4 AAC codec
Psychoacoustic model, Bit Allocation, Filterbank
Low-delay AAC codec
Perceptual Evaluation of Audio Quality (PEAQ)
MPEG Surround
Multi Channel Audio Effect Processing
Room Reverberation
Room Acoustics
Real-time DSP Programming/Optimization
Variant Platform Optimization
Fixed-Point DSP Programming
External links
Perceptual Signal Processing Lab homepage
Sound
|
https://en.wikipedia.org/wiki/Barotropic%20fluid
|
In fluid dynamics, a barotropic fluid is a fluid whose density is a function of pressure only. The barotropic fluid is a useful model of fluid behavior in a wide variety of scientific fields, from meteorology to astrophysics.
The density of most liquids is nearly constant (isopycnic), so it can be stated that their densities vary only weakly with pressure and temperature. Water, which varies only a few percent with temperature and salinity, may be approximated as barotropic. In general, air is not barotropic, as it is a function of temperature and pressure; but, under certain circumstances, the barotropic assumption can be useful.
In astrophysics, barotropic fluids are important in the study of stellar interiors or of the interstellar medium. One common class of barotropic model used in astrophysics is a polytropic fluid. Typically, the barotropic assumption is not very realistic.
In meteorology, a barotropic atmosphere is one that for which the density of the air depends only on pressure, as a result isobaric surfaces (constant-pressure surfaces) are also constant-density surfaces. Such isobaric surfaces will also be isothermal surfaces, hence (from the thermal wind equation) the geostrophic wind will not vary with depth. Hence, the motions of a rotating barotropic air mass is strongly constrained. The tropics are more nearly barotropic than mid-latitudes because temperature is more nearly horizontally uniform in the tropics.
A barotropic flow is a generalization of a b
|
https://en.wikipedia.org/wiki/Marek%20Huberath
|
Marek S. Huberath (pen name, born 1954) is a Polish professor of physics in the Jagiellonian University in Kraków and an award-winning science fiction and fantasy writer. His themes are philosophical, moral, and religious: how people become beasts or remain human in extreme circumstances. Many of his stories focus on death. Winner of the Zajdel Award in 1991 for a short story Kara większa and in 1997 for his novel Gniazdo Światów.
Works
Novels
Gniazdo światów (Nest of Worlds) (NOWA 2000) (English translation by Michael Kandel, Restless Books 2014)
Miasta pod skałą (Cities under the Rock) (Wydawnictwo Literackie 2005)
Vatran Auraio (Wydawnictwo Literackie 2010)
Zachodni portal Katedry w Lugdunum (Western Portal of the Cathedral in Lugdunum) (Wydawnictwo Literackie 2012)
Short story collections
Ostatni, którzy wyszli z raju (The Last to Leave Paradise) (Zysk i S-ka 1996)
Druga podobizna w alabastrze (Second Image in Alabaster) (Zysk i S-ka 1997)
Balsam długiego pożegnania (Balm of Long Farewell) (Wydawnictwo Literackie 2006)
Short stories
"Yoo Retoont, Sneogg. Ay Noo" translated by Michael Kandel on Words without Borders; in A Polish Book of Monsters (New York: PIASA Books, 2010)
"Balm of a Long Farewell" translated by Michael Kandel on Words without Borders
External links
Michael Kandel, Climbing with Huberath
Short story '"Yoo Retoont, Sneogg. Ay Noo." in English, translated by Michael Kandel
Short story "Balm of a Long Farewell." in English, translated by Michael Ka
|
https://en.wikipedia.org/wiki/Metropolitan-Vickers
|
Metropolitan-Vickers, Metrovick, or Metrovicks, was a British heavy electrical engineering company of the early-to-mid 20th century formerly known as British Westinghouse. Highly diversified, it was particularly well known for its industrial electrical equipment such as generators, steam turbines, switchgear, transformers, electronics and railway traction equipment. Metrovick holds a place in history as the builders of the first commercial transistor computer, the Metrovick 950, and the first British axial-flow jet engine, the Metropolitan-Vickers F.2. Its factory in Trafford Park, Manchester, was for most of the 20th century one of the biggest and most important heavy engineering facilities in Britain and the world.
History
Metrovick started as a way to separate the existing British Westinghouse Electrical and Manufacturing Company factories from United States control, which had proven to be a hindrance to gaining government contracts during the First World War. In 1917 a holding company was formed to try to find financing to buy the company's properties.
In May 1917, control of the holding company was obtained jointly by the Metropolitan Carriage, Wagon and Finance Company, of Birmingham, chaired by Dudley Docker, and Vickers Limited, of Barrow-in-Furness.<ref name=gillham-2>Gillham (1988), Chapter 2: The Manufacturers.</ref> On 15 March 1919, Docker agreed terms with Vickers, for Vickers to purchase all the shares of the Metropolitan Carriage, Wagon and Finance Company
|
https://en.wikipedia.org/wiki/Connectivity%20%28graph%20theory%29
|
In mathematics and computer science, connectivity is one of the basic concepts of graph theory: it asks for the minimum number of elements (nodes or edges) that need to be removed to separate the remaining nodes into two or more isolated subgraphs. It is closely related to the theory of network flow problems. The connectivity of a graph is an important measure of its resilience as a network.
Connected vertices and graphs
In an undirected graph , two vertices and are called connected if contains a path from to . Otherwise, they are called disconnected. If the two vertices are additionally connected by a path of length , i.e. by a single edge, the vertices are called adjacent.
A graph is said to be connected if every pair of vertices in the graph is connected. This means that there is a path between every pair of vertices. An undirected graph that is not connected is called disconnected. An undirected graph G is therefore disconnected if there exist two vertices in G such that no path in G has these vertices as endpoints. A graph with just one vertex is connected. An edgeless graph with two or more vertices is disconnected.
A directed graph is called weakly connected if replacing all of its directed edges with undirected edges produces a connected (undirected) graph. It is unilaterally connected or unilateral (also called semiconnected) if it contains a directed path from to or a directed path from to for every pair of vertices . It is strongly connected, or simply
|
https://en.wikipedia.org/wiki/Mary%20Adela%20Blagg
|
Mary Adela Blagg (17 May 1858 – 14 April 1944) was an English astronomer and was elected a fellow of the Royal Astronomical Society in 1916.
Biography
She was born in Cheadle, Staffordshire, and lived her entire life there. Mary was the daughter of a solicitor, John Charles Blagg, and France Caroline Foottit. She trained herself in mathematics by reading her brother's textbooks. In 1875 she was sent to a finishing school in Kensington where she studied algebra and German. She later worked as a Sunday school teacher and was the branch secretary of the Girls' Friendly Society.
By middle age she became interested in astronomy after attending a university extension course, taught by Joseph Hardcastle, John Herschel's grandson. Her tutor suggested working in the area of selenography, particularly on the problem of developing a uniform system of lunar nomenclature. (Several major lunar maps of the period had discrepancies in terms of naming the various features.)
In 1905 she was appointed by the newly formed International Association of Academies to build a collated list of all of the lunar features. She worked with Samuel Saunder on this very tedious and lengthy task, and the result was published in 1913. Her work produced a long list of discrepancies that the association would need to resolve. She also performed considerable work on the subject of variable stars, in collaboration with Professor H. H. Turner. These were published in a series of ten articles in the Monthly Not
|
https://en.wikipedia.org/wiki/HJ
|
HJ may refer to:
Science, technology, and mathematics
Hall–Janko group, a mathematical group
U.S. code for a cryptographic key change; see cryptoperiod
Other uses
, a two-letter combination used in some languages
hj-reduction in English, dropping the sound before
Hajji (Hj.), an Islamic honorific
Handjob
hic jacet ('here lies'), Latin phrase on gravestones
Hilal-i-Jurat, post-nominal for Pakistan honour
Hitler-Jugend (Hitler Youth)
Holden HJ, an Australian car 1974-1976
Hot Jupiter, a type of planet
Tasman Cargo Airlines, IATA airline designator
|
https://en.wikipedia.org/wiki/Energy%20level%20splitting
|
In quantum physics, energy level splitting or a split in an energy level of a quantum system occurs when a perturbation changes the system. The perturbation changes the corresponding Hamiltonian and the outcome is change in eigenvalues; several distinct energy levels emerge in place of the former degenerate (multi-state) level. This may occur because of external fields, quantum tunnelling between states, or other effects. The term is most commonly used in reference to the electron configuration in atoms or molecules.
The simplest case of level splitting is a quantum system with two states whose unperturbed Hamiltonian is a diagonal operator: , where is the identity matrix. Eigenstates and eigenvalues (energy levels) of a perturbed Hamiltonian
will be:
: the level, and
: the level,
so this degenerate eigenvalue splits in two whenever . Though, if a perturbed Hamiltonian is not diagonal for this quantum states basis , then Hamiltonian's eigenstates are linear combinations of these two states.
For a physical implementation such as a charged spin-½ particle in an external magnetic field, the z-axis of the coordinate system is required to be collinear with the magnetic field to obtain a Hamiltonian in the form above (the Pauli matrix corresponds to z-axis). These basis states, referred to as spin-up and spin-down, are hence eigenvectors of the perturbed Hamiltonian, so this level splitting is both easy to demonstrate mathematically and intuitively evident.
But in cases
|
https://en.wikipedia.org/wiki/Tullio%20Regge
|
Tullio Eugenio Regge (; July 11, 1931 – October 23, 2014) was an Italian theoretical physicist.
Biography
Regge obtained the laurea in physics from the University of Turin in 1952 under the direction of Mario Verde and Gleb Wataghin, and a PhD in physics from the University of Rochester in 1957 under the direction of Robert Marshak. From 1958 to 1959 Regge held a post at the Max Planck Institute for Physics where he worked with Werner Heisenberg. In 1961 he was appointed to the chair of Relativity at the University of Turin. He also held an appointment at the Institute for Advanced Study from 1965 to 1979. He was emeritus professor at the Polytechnic University of Turin while contributing work at CERN as a visiting scientist. Regge died on October 23, 2014. He was married to Rosanna Cester, physicist, by whom he had three children: Daniele, Marta and Anna.
In 1959, Regge discovered a mathematical property of potential scattering in the Schrödinger equation—that the scattering amplitude can be thought of as an analytic function of the angular momentum, and that the position of the poles determines power-law growth rates of the amplitude in the purely mathematical region of large values of the cosine of the scattering angle (i.e. , requiring complex angles). This formulation is known as Regge theory.
In the early 1960s, Regge introduced Regge calculus, a simplicial formulation of general relativity. Regge calculus was the first discrete gauge theory suitable for numeric
|
https://en.wikipedia.org/wiki/Sulfonic%20acid
|
In organic chemistry, sulfonic acid (or sulphonic acid) refers to a member of the class of organosulfur compounds with the general formula , where R is an organic alkyl or aryl group and the group a sulfonyl hydroxide. As a substituent, it is known as a sulfo group. A sulfonic acid can be thought of as sulfuric acid with one hydroxyl group replaced by an organic substituent. The parent compound (with the organic substituent replaced by hydrogen) is the parent sulfonic acid, , a tautomer of sulfurous acid, . Salts or esters of sulfonic acids are called sulfonates.
Preparation
Aryl sulfonic acids are produced by the process of sulfonation. Usually the sulfonating agent is sulfur trioxide. A large scale application of this method is the production of alkylbenzenesulfonic acids:
RC6H5 + SO3 -> RC6H4SO3H
In this reaction, sulfur trioxide is an electrophile and the arene is the nucleophile. The reaction is an example of electrophilic aromatic substitution.
Alkylsulfonic acids can be prepared by many methods. In sulfoxidation, alkanes are irradiated with a mixture of sulfur dioxide and oxygen. This reaction is employed industrially to produce alkyl sulfonic acids, which are used as surfactants.
RH + SO2 + 1/2 O2 -> RSO3H
Direct reaction of alkanes with sulfur trioxide is not generally useful, except for the conversion methanesulfonic acid to methanedisulfonic acid.
Many alkane sulfonic acids can be obtained by the addition of bisulfite to terminal alkenes. Bisulfite
|
https://en.wikipedia.org/wiki/Peter%20Galison
|
Peter Louis Galison (born May 17, 1955) is an American historian and philosopher of science. He is the Joseph Pellegrino University Professor in history of science and physics at Harvard University.
Biography
Galison received his B.A., M.A., and Ph.D., in both physics and history of science, at Harvard University. His publications include How Experiments End (1987), Image and Logic: A Material Culture of Microphysics (1997), and Einstein's Clocks, Poincaré's Maps (2003). His most recent book, co-authored with Lorraine Daston, is titled Objectivity (2007).
Before moving to Harvard, Galison taught for several years at Stanford University, where he was professor of history, philosophy, and physics. He is considered a member of the Stanford School of philosophy of science, a group that also includes Ian Hacking, John Dupré, and Nancy Cartwright.
Galison developed a film for the History Channel on the development of the hydrogen bomb, and has done work on the intersection of science with other disciplines, in particular art (along with his wife, Caroline A. Jones) and architecture. He is on the editorial board of Critical Inquiry and was a MacArthur Fellow in 1997. For his "outstanding contributions to the history of physics", Galison received the American Physical Society's Abraham Pais Prize in 2018.
Philosophical work
In Image and Logic, Galison explored the fundamental rift rising in the physical sciences: whether singular, visual accounts of scientific phenomena would b
|
https://en.wikipedia.org/wiki/Matthew%20Laird
|
Matthew Laird (born 1977) is a Canadian academic, activist and politician. Having helped lead numerous political campaigns he continues to work with community groups on social and environmental issues.
Laird was born and raised in Vancouver, British Columbia, earning a Bachelor of Science in Computer Science from the University of British Columbia. After spending some years in the private sector as a software developer he returned to academia to work in bioinformatic research at Simon Fraser University. He currently resides in the City of Vancouver.
Environmentalism
Laird has talked about being raised around recycling and green ideas as the basis for his environmental activism. While involved with transportation and sustainability advocacy most of his life he became most involved after moving to New Westminster in 2003.
He was a founding member of New Westminster Environmental Partners, a New Westminster focused non-partisan sustainability advocacy group. Some notable accomplishments while working with NWEP are the implementation of an anti-idling bylaw, a cosmetic pesticide ban, pedestrian safety improvements at New Westminster SkyTrain Station and a Sustainability Documentary Film Festival. Laird was also a proponent for New Westminster's Royal City Farmers Market and has served on the board of directors for three years.
Always an advocate for transit and sustainable transportation, Laird is a member of the Livable Region Coalition. In conjunction with his NWEP
|
https://en.wikipedia.org/wiki/Topological%20module
|
In mathematics, a topological module is a module over a topological ring such that scalar multiplication and addition are continuous.
Examples
A topological vector space is a topological module over a topological field.
An abelian topological group can be considered as a topological module over where is the ring of integers with the discrete topology.
A topological ring is a topological module over each of its subrings.
A more complicated example is the -adic topology on a ring and its modules. Let be an ideal of a ring The sets of the form for all and all positive integers form a base for a topology on that makes into a topological ring. Then for any left -module the sets of the form for all and all positive integers form a base for a topology on that makes into a topological module over the topological ring
See also
References
Algebra
Topology
Topological algebra
Topological groups
|
https://en.wikipedia.org/wiki/Nevil%20Story%20Maskelyne
|
Mervyn Herbert Nevil Story Maskelyne (3 September 1823 – 20 May 1911) was an English geologist and politician.
Scientific career
Educated at Wadham College, Oxford, Maskelyne taught mineralogy and chemistry at Oxford from 1851, before becoming a professor of mineralogy, 1856–95. He was Keeper of Minerals at the British Museum from 1857 to 1880. He was made an honorary Fellow of Wadham in 1873.
Maskelyne was also a pioneer of photography and an associate of Fox Talbot.
The meteoritic mineral maskelynite was named after him.
Family
Mervyn was the eldest son of Antony Mervin Reeve Story and Margaret Maskelyne, the daughter of the Astronomer Royal, Nevil Maskelyne. The family adopted the name of Maskelyne on Nevil's coming of age as they had inherited that family's estate at Basset Down in Wiltshire.
Mervyn married Thereza Mary Dillwyn-Llewelyn (1834 – 21 February 1926) - Welsh astronomer and pioneer in scientific photography - on 29 June 1858.
Their daughter Mary married writer and politician Hugh Oakeley Arnold-Forster on 29 July 1885, and Hugh and Mary's granddaughter Vanda Morton published Nevil's biography in 1987 (see references). Their daughter Thereza was an advocate for domestic science who married physicist Arthur William Rucker in 1892.
Political career
He was Member of Parliament (MP) for Cricklade as a Liberal, 1880–1886, and as Liberal Unionist, 1886–1892, and a member of Wiltshire County Council, 1889–1904.
Selected publications
A guide to the collection
|
https://en.wikipedia.org/wiki/141%20%28number%29
|
141 (one hundred [and] forty-one) is the natural number following 140 and preceding 142.
In mathematics
141 is:
a centered pentagonal number.
the sum of the sums of the divisors of the first 13 positive integers.
the second n to give a prime Cullen number (of the form n2n + 1).
an undulating number in base 10, with the previous being 131, and the next being 151.
the sixth hendecagonal (11-gonal) number.
a semiprime: a product of two prime numbers, namely 3 and 47. Since those prime factors are Gaussian primes, this means that 141 is a Blum integer.
a Hilbert prime
In the military
The Lockheed C-141 Starlifter was a United States Air Force military strategic airlifter
K-141 Kursk was a Russian nuclear cruise missile submarine, which sank in the Barents Sea on 12 August 2000
was a United States Navy ship during World War II
was a United States Navy during World War II
was a United States Navy during World War II
was a United States Navy following World War I
was a United States Navy during World War II
In transportation
London Buses route 141 is a Transport for London contracted bus route in London
141 Nottingham–Sutton-in-Ashfield is a bus route in England
The 141 C Ouest was a 2-8-2 steam locomotive of the Chemin de fer de l'État
British Rail Class 141 was the first production model of the Pacer diesel multiple units
Union des Transports Africains de Guinée Flight 141, which crashed in the Bight of Benin on December 25, 2003
The Saipa 141 car produc
|
https://en.wikipedia.org/wiki/Thermo%20Electron
|
Thermo Electron Corporation (NYSE: TMO) (incorporated 1956) was a major provider of analytical instruments and services for a variety of domains. It was founded in 1956 by George N. Hatsopoulos, an MIT PhD in mechanical engineering. Initial funding was provided by Peter M. Nomikos, a Harvard Business School graduate.
After graduating from Northeastern University in 1959 John Hatsopoulos (brother of George) later joined the company as Financial Controller. Arvin Smith joined the company in 1970, and was President from January 1998.
On May 14, 2006, Thermo and Fisher Scientific announced that they would merge in a tax-free, stock-for-stock exchange. The merged company became Thermo Fisher Scientific. On November 9, 2006, the companies announced that the merger had been completed. However, the Federal Trade Commission ruled that this acquisition was anticompetitive with regard to centrifugal evaporators, requiring Fisher to divest Genevac. In April 2007, Genevac was sold to Riverlake Partners LLC and the merger closed with FTC approval.
In 2011, the aggregated company Thermo Fisher Scientific had revenues of over $11 billion, and employed 37,000 people.
Products
Zetatron, a high-voltage neutron generating vacuum tube
References
External links
www.thermoelectron.com (25 June 2006 snapshot from Internet Archive)
Defunct technology companies of the United States
Electronics companies of the United States
Research support companies
Defunct manufacturing companies based
|
https://en.wikipedia.org/wiki/Dissociation%20%28chemistry%29
|
Dissociation in chemistry is a general process in which molecules (or ionic compounds such as salts, or complexes) separate or split into other things such as atoms, ions, or radicals, usually in a reversible manner. For instance, when an acid dissolves in water, a covalent bond between an electronegative atom and a hydrogen atom is broken by heterolytic fission, which gives a proton (H+) and a negative ion. Dissociation is the opposite of association or recombination.
Dissociation constant
For reversible dissociations in a chemical equilibrium
AB <=> A + B
the dissociation constant Kd is the ratio of dissociated to undissociated compound
where the brackets denote the equilibrium concentrations of the species.
Dissociation degree
The dissociation degree is the fraction of original solute molecules that have dissociated. It is usually indicated by the Greek symbol α. More accurately, degree of dissociation refers to the amount of solute dissociated into ions or radicals per mole. In case of very strong acids and bases, degree of dissociation will be close to 1. Less powerful acids and bases will have lesser degree of dissociation. There is a simple relationship between this parameter and the van 't Hoff factor . If the solute substance dissociates into ions, then
For instance, for the following dissociation
KCl <=> K+ + Cl-
As , we would have that .
Salts
The dissociation of salts by solvation in a solution, such as water, means the separation of the anions and catio
|
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.