source
stringlengths 31
207
| text
stringlengths 12
1.5k
|
|---|---|
https://en.wikipedia.org/wiki/Space-filling%20model
|
In chemistry, a space-filling model, also known as a calotte model, is a type of three-dimensional (3D) molecular model where the atoms are represented by spheres whose radii are proportional to the radii of the atoms and whose center-to-center distances are proportional to the distances between the atomic nuclei, all in the same scale. Atoms of different chemical elements are usually represented by spheres of different colors.
Space-filling calotte models are also referred to as CPK models after the chemists Robert Corey, Linus Pauling, and Walter Koltun, who over a span of time developed the modeling concept into a useful form. They are distinguished from other 3D representations, such as the ball-and-stick and skeletal models, by the use of the "full size" space-filling spheres for the atoms. The models are tactile and manually rotatable. They are useful for visualizing the effective shape and relative dimensions of a molecule, and (because of the rotatability) the shapes of the surface of the various conformers. On the other hand, these models mask the chemical bonds between the atoms, and make it difficult to see the structure of the molecule that is obscured by the atoms nearest to the viewer in a particular pose. For this reason, such models are of greater utility if they can be used dynamically, especially when used with complex molecules (e.g., see the greater understanding of the molecules shape given when the THC model is clicked on to rotate).
History
Space-fil
|
https://en.wikipedia.org/wiki/Flavor
|
Flavor or flavour is either the sensory perception of taste or smell, or a flavoring in food that produces such perception.
Flavor or flavour may also refer to:
Science
Flavors (programming language), an early object-oriented extension to Lisp
Flavour (particle physics), a quantum number of elementary particles related to their weak interactions
Flavor of Linux, another term for any particular Linux distribution; by extension, "flavor" can be applied to any program or other computer code that exists in more than one current variant at the same time
Film and TV
Flavors (film), romantic comedy concerning Asian-Indian immigrants in America
Music
Artists and bands
Flavor Flav (born 1959), former rap/hip-hop promoter and current reality television actor
Flavour N'abania (born 1983), Nigerian singer-songwriter
Flavor (band), minor hit with "Sally Had A Party" in 1968
Albums
Flavours (album), 1975 album by The Guess Who
Flavors (album), by American R&B girl group Tiffany Affair
Songs
"Flavor", 1994 song by the Jon Spencer Blues Explosion from their album Orange
"Flavors", a song by Gomez from their 2000 compilation album Abandoned Shopping Trolley Hotline
"Flavor", 2003 song by Every Little Thing from their album Many Pieces
"Flavor" (Iyanya song), 2012 single by Iyanya from his album Desire
"Flavor" (Tori Amos song), 2012 single by Tori Amos from her album Gold Dust
See also
Flava (disambiguation), for the slang pronunciation of the word
Deliciousness (TV series), an Am
|
https://en.wikipedia.org/wiki/Sergey%20Kara-Murza
|
Sergey Georgyevich Kara-Murza (; born January 23, 1939, in Moscow) is a Soviet and Russian chemist, historian, political philosopher and sociologist.
Biography
Sergey Kara-Murza was graduated with degree in chemistry from Moscow State University in 1961. Between 1966 and 1972 he worked as a Soviet chemical specialist in Cuba.
In 1983 Sergey Kara-Murza defended his doctoral thesis in history of science and technology and in 1988 became a professor.
Sergey Kara-Murza taught in Russia and Spain and authored several publications and academic studies dedicated to history, science and society.
His theory that the golden billion, the population of the most developed countries (including the poor) lives off the rest of humanity, is popular in the Russian-speaking world.
His most prominent works: Mind Manipulations published in 2000 was dedicated to establishing and describing the problem of manipulation of public opinion by pro-Western mass media in Russia and Soviet Civilization, a work about history, political and economic organization of USSR. In the late 1990s and early 2000s Sergey Kara-Murza wrote a number of political and philosophical works on Eurocentrism, Globalization and Color revolutions. His articles were frequent in left-wing/nationalist Russian newspapers such as Pravda, Alexander Prokhanov's Zavtra and Soviet Russia.
Sergey Kara-Murza became known for his anti-globalization, anti-liberal and anti-Westernist views; however, he also rejects traditional Marxist id
|
https://en.wikipedia.org/wiki/Robert%20J.%20Kolenkow
|
Robert J. Kolenkow is an American physicist and teacher. He is best known for being the coauthor, along with Daniel Kleppner, of a popular undergraduate physics textbook.
Kolenkow did his undergraduate work at the Massachusetts Institute of Technology, graduating in 1955. For a time, he was an associate professor of physics at MIT. His departure in 1971 generated some controversy on campus; he was regarded as an excellent teacher by his students, however, the administration was viewed as being more concerned about research than education when making its tenure decisions.
Kolenkow became a professor at Carleton College in Northfield, Minnesota. He also co-authored a textbook on physical geography which was favorably reviewed.
Books
External links
Column concerning Kolenkow's denial of tenure.
Year of birth missing (living people)
Living people
Massachusetts Institute of Technology alumni
Massachusetts Institute of Technology School of Science faculty
21st-century American physicists
American textbook writers
|
https://en.wikipedia.org/wiki/Primary%20pseudoperfect%20number
|
In mathematics, and particularly in number theory, N is a primary pseudoperfect number if it satisfies the Egyptian fraction equation
where the sum is over only the prime divisors of N.
Properties
Equivalently, N is a primary pseudoperfect number if it satisfies
Except for the primary pseudoperfect number N = 2, this expression gives a representation for N as the sum of distinct divisors of N. Therefore, each primary pseudoperfect number N (except N = 2) is also pseudoperfect.
The eight known primary pseudoperfect numbers are
2, 6, 42, 1806, 47058, 2214502422, 52495396602, 8490421583559688410706771261086 .
The first four of these numbers are one less than the corresponding numbers in Sylvester's sequence, but then the two sequences diverge.
It is unknown whether there are infinitely many primary pseudoperfect numbers, or whether there are any odd primary pseudoperfect numbers.
The prime factors of primary pseudoperfect numbers sometimes may provide solutions to Znám's problem, in which all elements of the solution set are prime. For instance, the prime factors of the primary pseudoperfect number 47058 form the solution set {2,3,11,23,31} to Znám's problem. However, the smaller primary pseudoperfect numbers 2, 6, 42, and 1806 do not correspond to solutions to Znám's problem in this way, as their sets of prime factors violate the requirement that no number in the set can equal one plus the product of the other numbers. Anne (1998) observes that there is exactly one solut
|
https://en.wikipedia.org/wiki/Avesthagen
|
Avesthagen Limited is an integrated systems biology platform company headquartered in Bangalore, India. It was founded as an academic startup in 1998 by Villoo Morawala-Patell, a Rockefeller Fellow and grantee within NCBS-UAS, Bangalore. Avesthagen started business operations on March 21, 2001 with Series-A round investment led by ICICI Ventures and Tata Industries. Dr.Villoo Morawala Patell, is the Chairperson and Managing Director of Avesthagen Limited.
The company developed a unique portfolio of high-potential pharmaceutical, nutrition and agro-industrial bio-based products and continues to create novel products through convergence of food, pharma and population genetics leading to "Predictive, Preventive, Personalized" Healthcare and Food security". The goal of PPP healthcare is to use the advanced tools of molecular genetics to predict how patients will respond to drugs, reducing harm and increasing benefit. The dual combination of diagnostic and treatment technologies is at the heart of personalized medicine and will continue to transform modern healthcare dramatically.
Avestagenome Project
The Avestagenome Project, founded by Dr.Villoo Morawala Patell was created to identify genetic risk factors within the Parsi population that predispose individuals to cancers and high morbidity diseases. Its database of genomic variants derived from the Parsi control population is used with other populations to identify early intervention and improve disease prevention strategies
|
https://en.wikipedia.org/wiki/Cahen%27s%20constant
|
In mathematics, Cahen's constant is defined as the value of an infinite series of unit fractions with alternating signs:
Here denotes Sylvester's sequence, which is defined recursively by
Combining these fractions in pairs leads to an alternative expansion of Cahen's constant as a series of positive unit fractions formed from the terms in even positions of Sylvester's sequence. This series for Cahen's constant forms its greedy Egyptian expansion:
This constant is named after (also known for the Cahen–Mellin integral), who was the first to introduce it and prove its irrationality.
Continued fraction expansion
The majority of naturally occurring mathematical constants have no known simple patterns in their continued fraction expansions. Nevertheless, the complete continued fraction expansion of Cahen's constant is known: it is
where the sequence of coefficients
is defined by the recurrence relation
All the partial quotients of this expansion are squares of integers. Davison and Shallit made use of the continued fraction expansion to prove that is transcendental.
Alternatively, one may express the partial quotients in the continued fraction expansion of Cahen's constant through the terms of Sylvester's sequence: To see this, we prove by induction on that . Indeed, we have , and if holds for some , then
where we used the recursion for in the first step respectively the recursion for in the final step. As a consequence, holds for every , from which it is easy
|
https://en.wikipedia.org/wiki/Category%20of%20finite-dimensional%20Hilbert%20spaces
|
In mathematics, the category FdHilb has all finite-dimensional Hilbert spaces for objects and the linear transformations between them as morphisms. Whereas the theory described by the normal category of Hilbert spaces, Hilb, is ordinary quantum mechanics, the corresponding theory on finite dimensional Hilbert spaces is called fdQM.
Properties
This category
is monoidal,
possesses finite biproducts, and
is dagger compact.
According to a theorem of Selinger, the category of finite-dimensional Hilbert spaces is complete in the dagger compact category. Many ideas from Hilbert spaces, such as the no-cloning theorem, hold in general for dagger compact categories. See that article for additional details.
References
Monoidal categories
Dagger categories
Hilbert spaces
|
https://en.wikipedia.org/wiki/Uniform%20topology
|
In mathematics, the uniform topology on a space may mean:
In functional analysis, it sometimes refers to a polar topology on a topological vector space.
In general topology, it is the topology carried by a uniform space.
In real analysis, it is the topology of uniform convergence.
|
https://en.wikipedia.org/wiki/Uniformly%20Cauchy%20sequence
|
In mathematics, a sequence of functions from a set S to a metric space M is said to be uniformly Cauchy if:
For all , there exists such that for all : whenever .
Another way of saying this is that as , where the uniform distance between two functions is defined by
Convergence criteria
A sequence of functions {fn} from S to M is pointwise Cauchy if, for each x ∈ S, the sequence {fn(x)} is a Cauchy sequence in M. This is a weaker condition than being uniformly Cauchy.
In general a sequence can be pointwise Cauchy and not pointwise convergent, or it can be uniformly Cauchy and not uniformly convergent. Nevertheless, if the metric space M is complete, then any pointwise Cauchy sequence converges pointwise to a function from S to M. Similarly, any uniformly Cauchy sequence will tend uniformly to such a function.
The uniform Cauchy property is frequently used when the S is not just a set, but a topological space, and M is a complete metric space. The following theorem holds:
Let S be a topological space and M a complete metric space. Then any uniformly Cauchy sequence of continuous functions fn : S → M tends uniformly to a unique continuous function f : S → M.
Generalization to uniform spaces
A sequence of functions from a set S to a uniform space U is said to be uniformly Cauchy if:
For all and for any entourage , there exists such that whenever .
See also
Modes of convergence (annotated index)
Functional analysis
Convergence (mathematics)
|
https://en.wikipedia.org/wiki/Gammasphere
|
The Gammasphere is a third generation gamma ray spectrometer used to study rare and exotic nuclear physics. It consists of 108 Compton-suppressed large volume, high-purity germanium detectors arranged in a spherical shell.
Gammasphere has been used to perform a variety of experiments in nuclear physics. Most experiments involve using heavy ion nuclear fusion to form a highly excited atomic nucleus. This nucleus may then emit protons, neutrons, or alpha particles followed by a shower of tens of gamma rays. Gammasphere is used to measure properties of these gamma-rays for tens of millions of such gamma ray showers. The resultant data are analyzed to gain a deeper understanding of the properties of nuclei.
Gammasphere was built in the early 1990s and has operated at the 88-inch cyclotron at Berkeley National Laboratory and at Argonne National Laboratory.
In the movie Hulk, Bruce Banner is zapped by a machine called the Gammasphere. The actual Gammasphere, which detects rather than emits gamma rays, was used as a model for the device shown in the movie.
See also
Canadian Penning Trap Mass Spectrometer
Helical Orbit Spectrometer (HELIOS)
References
External links
LBNL: LBL site.
ANL site
Gammasphere Online Booklet Homepage
Spectrometers
|
https://en.wikipedia.org/wiki/Populus%20trichocarpa
|
Populus trichocarpa, the black cottonwood, western balsam-poplar or California poplar, is a deciduous broadleaf tree species native to western North America. It is used for timber, and is notable as a model organism in plant biology.
Description
It is a large tree, growing to a height of and a trunk diameter over . It ranks 3rd in poplar species in the American Forests Champion Tree Registry. It is normally fairly short-lived, but some trees may live up to 400 years. A cottonwood in Willamette Mission State Park near Salem, Oregon, holds the national and world records. Last measured in April 2008, this black cottonwood was found to be standing at tall, around, with 527 points.
The bark is grey and covered with lenticels, becoming thick and deeply fissured on old trees. The bark can become hard enough to cause sparks when cut with a chainsaw. The stem is grey in the older parts and light brown in younger parts. The crown is usually roughly conical and quite dense. In large trees, the lower branches droop downwards. Spur shoots are common. The wood has a light coloring and a straight grain.
The leaves are usually long with a glossy, dark green upper side and glaucous, light grey-green underside; larger leaves may be up to long and may be produced on stump sprouts and very vigorous young trees. The leaves are alternate, elliptical with a crenate margin and an acute tip, and reticulate venation. The petiole is reddish. The buds are conical, long, narrow, and sticky, wi
|
https://en.wikipedia.org/wiki/Optimal%20stopping
|
In mathematics, the theory of optimal stopping or early stopping is concerned with the problem of choosing a time to take a particular action, in order to maximise an expected reward or minimise an expected cost. Optimal stopping problems can be found in areas of statistics, economics, and mathematical finance (related to the pricing of American options). A key example of an optimal stopping problem is the secretary problem. Optimal stopping problems can often be written in the form of a Bellman equation, and are therefore often solved using dynamic programming.
Definition
Discrete time case
Stopping rule problems are associated with two objects:
A sequence of random variables , whose joint distribution is something assumed to be known
A sequence of 'reward' functions which depend on the observed values of the random variables in 1:
Given those objects, the problem is as follows:
You are observing the sequence of random variables, and at each step , you can choose to either stop observing or continue
If you stop observing at step , you will receive reward
You want to choose a stopping rule to maximize your expected reward (or equivalently, minimize your expected loss)
Continuous time case
Consider a gain process defined on a filtered probability space and assume that is adapted to the filtration. The optimal stopping problem is to find the stopping time which maximizes the expected gain
where is called the value function. Here can take value .
A more s
|
https://en.wikipedia.org/wiki/Verdier%20duality
|
In mathematics, Verdier duality is a cohomological duality in algebraic topology that generalizes Poincaré duality for manifolds. Verdier duality was introduced in 1965 by as an analog for locally compact topological spaces of
Alexander Grothendieck's theory of
Poincaré duality in étale cohomology
for schemes in algebraic geometry. It is thus (together with the said étale theory and for example Grothendieck's coherent duality) one instance of Grothendieck's six operations formalism.
Verdier duality generalises the classical Poincaré duality of manifolds in two directions: it applies to continuous maps from one space to another (reducing to the classical case for the unique map from a manifold to a one-point space), and it applies to spaces that fail to be manifolds due to the presence of singularities. It is commonly encountered when studying constructible or perverse sheaves.
Verdier duality
Verdier duality states that (subject to suitable finiteness conditions discussed below)
certain derived image functors for sheaves are actually adjoint functors. There are two versions.
Global Verdier duality states that for a continuous map of locally compact Hausdorff spaces, the derived functor of the direct image with compact (or proper) supports has a right adjoint in the derived category of
sheaves, in other words, for (complexes of) sheaves (of abelian groups) on and on we have
Local Verdier duality states that
in the derived category of sheaves on Y.
It is import
|
https://en.wikipedia.org/wiki/Cryo
|
Cryo- is from the Ancient Greek κρύος (krúos, “ice, icy cold, chill, frost”). Uses of the prefix Cryo- include:
Physics and geology
Cryogenics, the study of the production and behaviour of materials at very low temperatures and the study of producing extremely low temperatures
Cryoelectronics, the study of superconductivity under cryogenic conditions and its applications
Cryosphere, those portions of Earth's surface where water ice naturally occurs
Cryotron, a switch that uses superconductivity
Cryovolcano, a theoretical type of volcano that erupts volatiles instead of molten rock
Biology and medicine
Cryobiology, the branch of biology that studies the effects of low temperatures on living things
Cryonics, the low-temperature preservation of people who cannot be sustained by contemporary medicine
Cryoprecipitate, a blood-derived protein product used to treat some bleeding disorders
Cryotherapy, medical treatment using cold
Cryoablation, tissue removal using cold
Cryosurgery, surgery using cold
Cryo-electron microscopy (cryoEM), a technique that fires beams of electrons at proteins that have been frozen in solution, to deduce the biomolecules’ structure
Other uses
Cryo Interactive, a video game company
Cryos, a planet in the video game Darkspore
See also
Kryo, a brand of CPUs by Qualcomm
External links
Cryogenics
Cryobiology
Cryonics
Superconductivity
|
https://en.wikipedia.org/wiki/FirstDefender
|
FirstDefender is a handheld liquid and solid chemical identification instrument which uses a method of analysis called Raman spectroscopy. It is designed for use by first responders, homeland security, law enforcers and forensic chemistry personnel for immediate identification of unknown solids, liquids, and mixtures. This includes narcotics, explosives, white powders, chemical weapons, WMDs and toxic industrial chemicals. The detector identifies substances even through the walls of their containers. It is used by some airport officials in the United States to detect liquid explosives.
It won the Bronze medal in the 2006 International Design Excellence Awards in the Medical & Scientific Products Category.
References
http://www.ahuracorp.com/first_defender.html
Explosive detection
|
https://en.wikipedia.org/wiki/Hirzebruch%20signature%20theorem
|
In differential topology, an area of mathematics, the Hirzebruch signature theorem (sometimes called the Hirzebruch index theorem)
is Friedrich Hirzebruch's 1954 result expressing the signature
of a smooth closed oriented manifold by a linear combination of Pontryagin numbers called the
L-genus.
It was used in the proof of the Hirzebruch–Riemann–Roch theorem.
Statement of the theorem
The L-genus is the genus for the multiplicative sequence of polynomials
associated to the characteristic power series
The first two of the resulting L-polynomials are:
(for further L-polynomials see or ).
By taking for the the Pontryagin classes of the tangent bundle of a 4n dimensional smooth closed oriented
manifold M one obtains the L-classes of M.
Hirzebruch showed that the n-th L-class of M evaluated on the fundamental class of M, , is equal to , the signature of M
(i.e. the signature of the intersection form on the 2nth cohomology group of M):
Sketch of proof of the signature theorem
René Thom had earlier proved that the signature was given by some linear combination of Pontryagin numbers, and Hirzebruch found the exact formula for this linear combination
by introducing the notion of the genus of a multiplicative sequence.
Since the rational oriented cobordism ring is equal to
the polynomial algebra generated by the oriented cobordism classes
of the even dimensional complex projective spaces,
it is enough to verify that
for all i.
Generalizations
The signature theorem is a
|
https://en.wikipedia.org/wiki/Bruss
|
Bruss may refer to:
Brös an alternate spelling of a preparation of cheese and grappa
Franz Thomas Bruss, a Belgian-German professor of mathematics at the Université Libre de Bruxelles
Logan Bruss (born 1999), American football player
Robert Bruss, a real estate attorney and syndicated columnist known as "the Dear Abby of real estate"
Arthur Atkinson aka Arthur "Artie" 'Bruss' Atkinson, an English former professional rugby league footballer
Surnames from given names
|
https://en.wikipedia.org/wiki/Theta%20characteristic
|
In mathematics, a theta characteristic of a non-singular algebraic curve C is a divisor class Θ such that 2Θ is the canonical class. In terms of holomorphic line bundles L on a connected compact Riemann surface, it is therefore L such that L2 is the canonical bundle, here also equivalently the holomorphic cotangent bundle. In terms of algebraic geometry, the equivalent definition is as an invertible sheaf, which squares to the sheaf of differentials of the first kind. Theta characteristics were introduced by
History and genus 1
The importance of this concept was realised first in the analytic theory of theta functions, and geometrically in the theory of bitangents. In the analytic theory, there are four fundamental theta functions in the theory of Jacobian elliptic functions. Their labels are in effect the theta characteristics of an elliptic curve. For that case, the canonical class is trivial (zero in the divisor class group) and so the theta characteristics of an elliptic curve E over the complex numbers are seen to be in 1-1 correspondence with the four points P on E with 2P = 0; this is counting of the solutions is clear from the group structure, a product of two circle groups, when E is treated as a complex torus.
Higher genus
For C of genus 0 there is one such divisor class, namely the class of -P, where P is any point on the curve. In case of higher genus g, assuming the field over which C is defined does not have characteristic 2, the theta characteristics can be
|
https://en.wikipedia.org/wiki/Mohinder%20Suresh
|
Mohinder Suresh is a fictional character on the NBC drama Heroes, portrayed by Sendhil Ramamurthy. He is from Chennai, Tamil Nadu, India and is a genetics professor at the University of Madras. Mohinder is attempting to find the truth behind the sudden death of his father, Chandra Suresh (portrayed by Erick Avari), and to continue his father's research of finding 'superhuman' beings on Earth. In character, Suresh also provides many episodes with opening and/or closing dialogue, generally philosophical musings regarding the events that take place during the episode.
The role of Mohinder was originally written to be a 55-year-old geneticist looking for super-powered humans. However, Sendhil Ramamurthy's audition was so convincing that the main character part was rewritten to be a younger geneticist following in his father's footsteps. The concept of the older geneticist was spun off into the minor, yet central, character of Chandra Suresh.
Character history
Genesis
After hearing news of his father's death in New York, Mohinder suspects that his father was murdered to silence the findings of his genetics research.
Mohinder travels to Brooklyn, where he rents his father's other apartment. Although it is in disarray, much of the material is still there and Mohinder begins to reorganize it. To makes ends meet during his lengthy stay, Mohinder takes a job as a taxi driver and picks up a passenger named Peter Petrelli, who asks him about "being special." Although Mohinder is s
|
https://en.wikipedia.org/wiki/Sparsetooth%20dogfish
|
The sparsetooth dogfish (Scymnodalatias oligodon) is a very rare sleeper shark of the family Somniosidae, the holotype of which was taken in the subtropical southeast Pacific at a depth of up to 200 m. Its biology is unknown.
References
Scymnodalatias
Fish described in 1988
|
https://en.wikipedia.org/wiki/Lowest%20common%20ancestor
|
In graph theory and computer science, the lowest common ancestor (LCA) (also called least common ancestor) of two nodes and in a tree or directed acyclic graph (DAG) is the lowest (i.e. deepest) node that has both and as descendants, where we define each node to be a descendant of itself (so if has a direct connection from , is the lowest common ancestor).
The LCA of and in is the shared ancestor of and that is located farthest from the root. Computation of lowest common ancestors may be useful, for instance, as part of a procedure for determining the distance between pairs of nodes in a tree: the distance from to can be computed as the distance from the root to , plus the distance from the root to , minus twice the distance from the root to their lowest common ancestor .
In a tree data structure where each node points to its parent, the lowest common ancestor can be easily determined by finding the first intersection of the paths from and to the root. In general, the computational time required for this algorithm is where is the height of the tree (length of longest path from a leaf to the root). However, there exist several algorithms for processing trees so that lowest common ancestors may be found more quickly. Tarjan's off-line lowest common ancestors algorithm, for example, preprocesses a tree in linear time to provide constant-time LCA queries. In general DAGs, similar algorithms exist, but with super-linear complexity.
History
The lowest common
|
https://en.wikipedia.org/wiki/Functionally%20graded%20material
|
In materials science Functionally Graded Materials (FGMs) may be characterized by the variation in composition and structure gradually over volume, resulting in corresponding changes in the properties of the material. The materials can be designed for specific function and applications. Various approaches based on the bulk (particulate processing), preform processing, layer processing and melt processing are used to fabricate the functionally graded materials.
History
The concept of FGM was first considered in Japan in 1984 during a space plane project, where a combination of materials used would serve the purpose of a thermal barrier capable of withstanding a surface temperature of 2000 K and a temperature gradient of 1000 K across a 10 mm section. In recent years this concept has become more popular in Europe, particularly in Germany. A transregional collaborative research center (SFB Transregio) is funded since 2006 in order to exploit the potential of grading monomaterials, such as steel, aluminium and polypropylen, by using thermomechanically coupled manufacturing processes.
General information
FGMs can vary in either composition and structure, for example, porosity, or both to produce the resulting gradient. The gradient can be categorized as either continuous or discontinuous, which exhibits a stepwise gradient.
There are several examples of FGMs in nature, including bamboo and bone, which alter their microstructure to create a material property gradient. In biolog
|
https://en.wikipedia.org/wiki/Ivan%20Ili%C4%87%20%28pianist%29
|
Ivan Ilić (; born August 14, 1978) is a Serbian-American pianist. He lives in Paris.
Early life
Ilić was born in Palo Alto, in the United States. He attended the University of California, Berkeley in the U.S. where he took degrees in mathematics and music. Ilić also briefly studied at the San Francisco Conservatory of Music before pursuing graduate studies at the Conservatoire de Paris, earning a Premier Prix, and finally at the École Normale de Musique de Paris. His teachers in France included François-René Duchâble, Christian Ivaldi, and Jacques Rouvier.
Career
Ilić performs primarily as a soloist. His recording of Debussy's 24 Préludes was released in October 2008 on the French record label Paraty and won Mezzo TV's Critics' Choice Award in France. The disc was also a Top Five CD of the year by a critic at Fanfare Magazine and a Top Five CD of the Month by the French website Classique News. Ilić rearranged the order of the Préludes on the album, a controversial choice which he defended in several interviews.
Ilić's next album was dedicated to the left-hand Studies on Chopin's Études by Leopold Godowsky. The disc was the Classical CD of the Week of The Daily Telegraph, a Top 5 CD of Mitteldeutscher Rundfunk Figaro, and a Top 5 CD of Classique News.
Ilić has performed at Carnegie Hall, Weill Hall in New York, Wigmore Hall, Glenn Gould Studio, and Ireland's National Concert Hall.
Discography
Ivan Ilić, pianiste - oeuvres de Brahms, Beethoven et Chopin, Mairie de Paris
|
https://en.wikipedia.org/wiki/BQM-147%20Dragon
|
The BAI Aerosystems (BAIA) BQM-147 Dragon unmanned aerial vehicle is a tactical battlefield UAV operated by the US Marine Corps.
Development
The Dragon began life in 1986, when the US Marines Corps contracted with the Applied Physics Laboratory (APL), an offshoot of Johns Hopkins University in Baltimore, Maryland, that works on government technology development contracts, to build a small piston-powered UAV as an "expendable jammer" for battlefield electronics warfare. The program was logically named "ExJam". BAI Aerosystems was a subcontractor to APL and provided airframe parts.
"Creeping featurism" infected the program as the Marines considered more applications for the little drone, and in 1987 the program was given the new name of BQM-147A "Expendable Drone" or "Exdrone". The communications-jammer configuration of the vehicle was tested in the University of Maryland Glenn L. Martin wind tunnel, and successfully completed developmental flight testing at Naval Air Station Patuxent River and a combined Developmental Test/Operational Test at White Sands Missile Range. However, APL wasn't able to meet the schedule requested by the Marines for fielding the Exdrone, and so the program was passed on to BAI Aerosystems, with the Navy assisting by developing a video imaging system for tactical reconnaissance.
The NASA Langley Flight Research Center also assisted in the development effort, performing wind-tunnel tests and making recommendations for aerodynamic improvements, and
|
https://en.wikipedia.org/wiki/Woodward%2C%20Inc.
|
Woodward, Inc. is an American designer, manufacturer, and service provider of control systems and control system components (e.g. fuel pumps, engine controls, actuators, air valves, fuel nozzles, and electronics) for aircraft engines, industrial engines and turbines, power generation and mobile industrial equipment. The company also provides military devices and other equipment for defense.
Woodward, Inc. was founded as The Woodward Governor Company by Amos Woodward in 1870. Initially, the company made controls for waterwheels (first patent No. 103,813), and then moved to hydro turbines. In the 1920s and 1930s, Woodward began designing controls for diesel and other reciprocating engines and for industrial turbines. Also in the 1930s, Woodward developed a governor for variable-pitch aircraft propellers. Woodward parts were notably used in the GE engine on United States military's first turbine-powered aircraft. Starting in the 1950s, Woodward began designing electronic controls, first analog and then digital units.
Historical information
The company was founded in Rockford, Illinois, in 1870 with Amos W. Woodward's invention of a non compensating mechanical waterwheel governor (U.S. patent No. 103,813). Thirty years later, his son Elmer patented the first successful mechanical compensating governor for hydraulic turbines (U.S. patent No. 583,527). In 1933, the company expanded its product line to include diesel engine controls (U.S. patent No. 2,039,507) and aircraft propell
|
https://en.wikipedia.org/wiki/Electron%20magnetic%20resonance
|
In physics, biology and chemistry, electron magnetic resonance (EMR) is an interdisciplinary field that covers both electron paramagnetic resonance (EPR, also known as electron spin resonance – ESR) and electron cyclotron resonance (ECR). EMR looks at electrons rather than nuclei or ions as in nuclear magnetic resonance (NMR) and ion cyclotron resonance (ICR) respectively.
References
Electromagnetism
|
https://en.wikipedia.org/wiki/Strike%20Force%20Bowling
|
Strike Force Bowling is a video game of the sports genre released in 2004 by LAB Rats. A previous game, Fast Lanes Bowling, was published by Enlight Software for Microsoft Windows. The two games are very similar sharing the same physics engine and graphics, although Strike Force featured more locations as well as left-handed, and reverse-hook bowlers. LAB Rats assisted in the development of Brunswick Circuit Pro Bowling so the game has the same physics engine, but has a more fantasy-oriented theme. Strike Force features 14 places to Bowl (12 in Fast Lanes) and 8 Playable characters. There are only 7 locations, but each has its own "nighttime" variant which is unlocked as a secret stage. It also features Golf Mode, Challenge Mode, Skins, and Tournaments. There are also 14 different bowling balls to use, such as the Lightning, and level specific ones like the Bone Crasher and Pharaoh's Magic.
Reception
The Xbox version and Fast Lanes Bowling received "mixed" reviews, while the PlayStation 2 and GameCube versions received "generally unfavorable reviews", according to the review aggregation website Metacritic. TeamXbox gave the game a mixed review about two months before its U.S. release date.
References
External links
2004 video games
Crave Entertainment games
GameCube games
PlayStation 2 games
PlayStation Network games
Windows games
Xbox games
Bowling video games
Multiplayer and single-player video games
Video games developed in the United States
RenderWare games
Enlight S
|
https://en.wikipedia.org/wiki/Configuration%20%28geometry%29
|
In mathematics, specifically projective geometry, a configuration in the plane consists of a finite set of points, and a finite arrangement of lines, such that each point is incident to the same number of lines and each line is incident to the same number of points.
Although certain specific configurations had been studied earlier (for instance by Thomas Kirkman in 1849), the formal study of configurations was first introduced by Theodor Reye in 1876, in the second edition of his book Geometrie der Lage, in the context of a discussion of Desargues' theorem. Ernst Steinitz wrote his dissertation on the subject in 1894, and they were popularized by Hilbert and Cohn-Vossen's 1932 book Anschauliche Geometrie, reprinted in English as .
Configurations may be studied either as concrete sets of points and lines in a specific geometry, such as the Euclidean or projective planes (these are said to be realizable in that geometry), or as a type of abstract incidence geometry. In the latter case they are closely related to regular hypergraphs and biregular bipartite graphs, but with some additional restrictions: every two points of the incidence structure can be associated with at most one line, and every two lines can be associated with at most one point. That is, the girth of the corresponding bipartite graph (the Levi graph of the configuration) must be at least six.
Notation
A configuration in the plane is denoted by (), where is the number of points, the number of lines, the nu
|
https://en.wikipedia.org/wiki/Impact%20of%20nanotechnology
|
The impact of nanotechnology extends from its medical, ethical, mental, legal and environmental applications, to fields such as engineering, biology, chemistry, computing, materials science, and communications.
Major benefits of nanotechnology include improved manufacturing methods, water purification systems, energy systems, physical enhancement, nanomedicine, better food production methods, nutrition and large-scale infrastructure auto-fabrication. Nanotechnology's reduced size may allow for automation of tasks which were previously inaccessible due to physical restrictions, which in turn may reduce labor, land, or maintenance requirements placed on humans.
Potential risks include environmental, health, and safety issues; transitional effects such as displacement of traditional industries as the products of nanotechnology become dominant, which are of concern to privacy rights advocates. These may be particularly important if potential negative effects of nanoparticles are overlooked.
Whether nanotechnology merits special government regulation is a controversial issue. Regulatory bodies such as the United States Environmental Protection Agency and the Health and Consumer Protection Directorate of the European Commission have started dealing with the potential risks of nanoparticles. The organic food sector has been the first to act with the regulated exclusion of engineered nanoparticles from certified organic produce, firstly in Australia and the UK, and more recently i
|
https://en.wikipedia.org/wiki/Homer%20A.%20McCrerey
|
Homer Alex McCrerey (July 29, 1919 – 1999) became U.S. Navy Meteorologist and oceanographer for CINCPACFLT until 1972.
Biography
US Navy Captain McCrerey was born in Hiawatha, Brown County, Kansas. During 1941 he graduated from Baker University in Baldwin City, Kansas with a mathematics degree. Homer was commissioned at the US Naval Academy in 1942. He completed Naval Postgraduate School in 1952. For over 20 years, he advanced both the art and science of computer-aided mathematical modeling that improved global weather forecasting.
He served in the Navy during World War II as ship's engineer on USS Strive and later as a meteorologist in the Naval Weather Service. He served as commanding officer of Fleet Weather Central at several posts. He was decorated nine times during his 31-year career and received a United Nations Service Medal and a National Defense Service Medal.
During his tour with CINCPACFLT while based at Pearl Harbor, Hawaii, McCrerey collaborated with Mid-Pacific Ocean near-peer mentors to help ensure effective NASA Apollo Program Command Capsule Recoveries coordinated by Pacific Recovery Forces (CTF 130).
See also
Bioneering
Military meteorology
CTF 130
David C. Richardson (admiral)
CDC 1604 at FOCCPAC Kunia, Hawaii
Keyhole Markup Language (Wx data formatting)
University of Kansas#Academics (Computing innovations)
The Blue Marble (CTF 130 Support)
External links
Family Search
Spouse: Anna Mae (Gold) McCrerey Obituary
1919 births
1999 deaths
Amer
|
https://en.wikipedia.org/wiki/Nonexistent%20objects
|
In metaphysics and ontology, Austrian philosopher Alexius Meinong advanced nonexistent objects in the 19th and 20th centuries within a "theory of objects". He was interested in intentional states which are directed at nonexistent objects. Starting with the "principle of intentionality", mental phenomena are intentionally directed towards an object. People may imagine, desire or fear something that does not exist. Other philosophers concluded that intentionality is not a real relation and therefore does not require the existence of an object, while Meinong concluded there is an object for every mental state whatsoever—if not an existent then at least a nonexistent one.
Round square copula
The round square copula is a common example of the dual copula strategy used in reference to the "problem of nonexistent objects" as well as their relation to problems in modern philosophy of language.
The issue arose, most notably, between the theories of contemporary philosophers Alexius Meinong (see Meinong's 1904 book Investigations in Theory of Objects and Psychology) and Bertrand Russell (see Russell's 1905 article "On Denoting"). Russell's critique of Meinong's theory of objects, also known as the Russellian view, became the established view on the problem of nonexistent objects.
In late modern philosophy, the concept of the "square circle" () had also been discussed before in Gottlob Frege's The Foundations of Arithmetic (1884).
The dual copula strategy
The strategy employed is
|
https://en.wikipedia.org/wiki/Biochemistry%20of%20Alzheimer%27s%20disease
|
The biochemistry of Alzheimer's disease, the most common cause of dementia, is not yet very well understood. Alzheimer's disease (AD) has been identified as a proteopathy: a protein misfolding disease due to the accumulation of abnormally folded amyloid beta (Aβ) protein in the brain. Amyloid beta is a short peptide that is an abnormal proteolytic byproduct of the transmembrane protein amyloid-beta precursor protein (APP), whose function is unclear but thought to be involved in neuronal development. The presenilins are components of proteolytic complex involved in APP processing and degradation.
Amyloid beta monomers are soluble and contain short regions of beta sheet and polyproline II helix secondary structures in solution, though they are largely alpha helical in membranes; however, at sufficiently high concentration, they undergo a dramatic conformational change to form a beta sheet-rich tertiary structure that aggregates to form amyloid fibrils. These fibrils and oligomeric forms of Aβ deposit outside neurons in formations known as senile plaques. There are different types of plaques, including the diffuse, compact, cored or neuritic plaque types, as well as Aβ deposits in the walls of small blood vessel walls in the brain called cerebral amyloid angiopathy.
AD is also considered a tauopathy due to abnormal aggregation of the tau protein, a microtubule-associated protein expressed in neurons that normally acts to stabilize microtubules in the cell cytoskeleton. Like m
|
https://en.wikipedia.org/wiki/Terence%20Parsons
|
Terence Dwight Parsons (1939–2022) was an American philosopher, specializing in philosophy of language and metaphysics. He was emeritus professor of philosophy at UCLA.
Life and career
Parsons was born in Endicott, New York and graduated from the University of Rochester with a BA in physics. He received his PhD from Stanford University in 1966. He was a full-time faculty member at the University of Illinois at Chicago from 1965 to 1972, at the University of Massachusetts at Amherst from 1972 to 1979, at the University of California at Irvine from 1979 to 2000, and at the University of California at Los Angeles from 2000 to 2012. In 2007, he was elected to the American Academy of Arts and Sciences.
Philosophical work
Parsons worked on the semantics of natural language to develop theories of truth and meaning for natural language similar to those devised for artificial languages by philosophical logicians. Heavily influenced by Alexius Meinong, he wrote Nonexistent Objects (1980), which dealt with possible world theory in order to defend the reality of nonexistent objects.
Works
Nonexistent Objects, Yale University Press, 1980.
Events in the Semantics of English, MIT Press, 1990.
Indeterminate Identity, Oxford University Press, 2000.
Articulating Medieval Logic, Oxford University Press, 2014.
See also
Round square copula
References
External links
Parson's UCLA website
Living people
Analytic philosophers
Metaphysicians
Abstract object theory
1939 births
Universit
|
https://en.wikipedia.org/wiki/Noneism
|
Noneism, also known as modal Meinongianism (named after Alexius Meinong), is a theory in logic and metaphysics. It holds that some things do not exist. It was first coined by Richard Routley in 1980 and appropriated again in 2005 by Graham Priest.
Overview
Noneism holds that some things do not exist. That is, we can quantify over non-existent objects ("items") using the so-called particular quantifier (also known—misleadingly in the view of noneists—as the existential quantifier). They also hold that "there is" is like "exist", rather than like the particular quantifier. Thus, they deny that there are things that do not exist. On this theory, there are no empty names, wherefore the "problem of empty names" that afflicts many theories about names (in particular, Millianism), is not a problem at all.
While Priest also espouses dialetheism, he maintains that his dialetheism is mostly capable of being separated out from his noneism. The connection is that impossible objects may exist in impossible worlds, much as nonexistent objects may exist in possible (but not actual) worlds.
Richard Routley's book, Exploring Meinong's Jungle and Beyond: An Investigation of Noneism and the Theory of Items, was published in 1980, while the first edition of Priest's book entitled Towards Non-Being: The Logic and Metaphysics of Intentionality was published in 2005 (second revised edition in 2016).
See also
Abstract object theory
Meinong's jungle
Plato's beard
Possible world
References
20th
|
https://en.wikipedia.org/wiki/Leonid%20Dushkin
|
Leonid Stepanovich Dushkin (Леонид Степанович Душкин) (August 15, 1910 in the Spirove settlement of the Tver region – April 4, 1990), was a major pioneer of Soviet rocket engine technology.
He graduated from Moscow State University with a degree in mathematics and mechanics. In October 1932, he joined Fridrikh Tsander's brigade of GIRD, the Moscow rocket research group. He assisted in the creation of their first rocket engine OR-2, and after Tsander's death, he oversaw the creation of engine "10" which powered the first Soviet liquid-fuel rocket, GIRD-X.
Dushkin became part of the Reactive Scientific Research Institute (RNII) when GIRD and the Gas Dynamics Laboratory (GDL) merged in 1933.
Dushkin's engines were among the first to be regeneratively cooled, and he also experimented with uncooled engines of high-temperature ceramic. The 12K engines were both types, and powered the Aviavnito rocket.
After the arrest of Valentin Glushko, Dushkin took over the development of rocket engines for the rocket-enhanced fighter plane RP-318. He became the leader of the department of liquid propellant rocket engines the NII-3 beginning in January 1938. Starting with Glushko's engines (ORM-65 and RD-1), he began a series of important engineering transformations, moving the fuel injectors to a head at one end of a cylindrical chamber, typical of modern design. The RDA-150, RDA-300 used nitric acid as an oxidizer, RDK-150 used liquid oxygen.
The 1100 kgf thrust engine, D-1-A-1100
|
https://en.wikipedia.org/wiki/Philip%20Rubin
|
Philip E. Rubin (born May 22, 1949) is an American cognitive scientist, technologist, and science administrator known for raising the visibility of behavioral and cognitive science, neuroscience, and ethical issues related to science, technology, and medicine, at a national level.
His research career is noted for his theoretical contributions and pioneering technological developments, starting in the 1970s, related to speech synthesis and speech production, including articulatory synthesis (computational modeling of the physiology and acoustics of speech production) and sinewave synthesis, and their use in studying complex temporal events, particularly understanding the biological bases of speech and language.
He is the President of the Federation of Associations in Behavioral and Brain Sciences (FABBS). He is also Chair of the Board of Directors of Haskins Laboratories in New Haven, Connecticut, where he is Chief Executive Officer emeritus and was for many years a senior scientist. In addition, he is a Professor Adjunct in the Department of Surgery, Otolaryngology at the Yale University School of Medicine, a Research Affiliate in the Department of Psychology at Yale University, a Fellow at Yale's Trumbull College,
and a Trustee of the University of Connecticut.
From 2012 through Feb. 2015 he was the Principal Assistant Director for Science at the Office of Science and Technology Policy (OSTP) in the Executive Office of the President of the United States, and led the
|
https://en.wikipedia.org/wiki/Eric%20A.%20Walker%20%28engineer%29
|
Eric Arthur Walker (April 29, 1910 – February 17, 1995) was president of the Pennsylvania State University from 1956 to 1970 and a founding member of the National Academy of Engineering.
Biography
Born in Long Eaton, England, Dr. Walker earned a Bachelor's degree from Harvard University in Electrical Engineering, a master's degree in business administration, and doctorate in general science and engineering from Harvard.
During World War II, Walker was associate director of the Underwater Sound Laboratory, initially located at Harvard, but relocated to the campus of Penn State University. Dr. Walker remained at Penn State, becoming head of the Department of Electrical Engineering, then Dean of the College of Engineering and Architecture in 1951. Next Dr. Walker became vice president for research at Penn State in 1956, and President of the University, also in 1956.
Penn State experienced changes and growth during the Presidency of Dr. Walker. The post-war student population at the university increased from 13,000 to 40,000, becoming one of the largest universities in the United States. Dr. Walker also oversaw the creation of the Milton S. Hershey Medical Center, and research expenditures for the university grew from $8,000,000 in 1956-57 to $36,000,000 in 1969-70.
Dr. Walker served as Vice-Chair of President Eisenhower's Committee on Scientists and Engineers from 1956-1958.
Legacy
The Eric A. Walker building on Penn State's campus is named in honor of Dr. Walker. It house
|
https://en.wikipedia.org/wiki/D%27Alembert%27s%20equation
|
In mathematics, d'Alembert's equation is a first order nonlinear ordinary differential equation, named after the French mathematician Jean le Rond d'Alembert. The equation reads as
where . After differentiating once, and rearranging we have
The above equation is linear. When , d'Alembert's equation is reduced to Clairaut's equation.
References
Eponymous equations of physics
Mathematical physics
Differential equations
Ordinary differential equations
|
https://en.wikipedia.org/wiki/Bharat%20Desai
|
Bharat Desai (Hindi: भरत देसाई; born November 1952) is an American billionaire businessman, and the co-founder and chairman of Syntel.
Early life
Bharat Desai was born in November 1952, in Kenya. He is of Gujarati Indian origin. In his childhood, he lived in Mombasa and Ahmedabad. Desai received a bachelor's degree in electrical engineering from the Indian Institute of Technology Bombay and an MBA in finance from the Stephen M. Ross School of Business.
Career
Desai co-founded Syntel, with his wife Neerja Sethi, of which he is the chairman.
Desai is a board member of several educational institutions, including the John F. Kennedy School of Government at Harvard University, Students in Free Enterprise (SIFE) and the Stephen M. Ross School of Business at the University of Michigan.
Personal life
He is married to Neerja Sethi, and they have two children.
References
Living people
1952 births
American billionaires
American people of Indian descent
American businesspeople
Ross School of Business alumni
Harvard Kennedy School people
IIT Bombay alumni
Gujarati people
American people of Gujarati descent
|
https://en.wikipedia.org/wiki/Interchange%20of%20limiting%20operations
|
In mathematics, the study of interchange of limiting operations is one of the major concerns of mathematical analysis, in that two given limiting operations, say L and M, cannot be assumed to give the same result when applied in either order. One of the historical sources for this theory is the study of trigonometric series.
Formulation
In symbols, the assumption
LM = ML,
where the left-hand side means that M is applied first, then L, and vice versa on the right-hand side, is not a valid equation between mathematical operators, under all circumstances and for all operands. An algebraist would say that the operations do not commute. The approach taken in analysis is somewhat different. Conclusions that assume limiting operations do 'commute' are called formal. The analyst tries to delineate conditions under which such conclusions are valid; in other words mathematical rigour is established by the specification of some set of sufficient conditions for the formal analysis to hold. This approach justifies, for example, the notion of uniform convergence. It is relatively rare for such sufficient conditions to be also necessary, so that a sharper piece of analysis may extend the domain of validity of formal results.
Professionally speaking, therefore, analysts push the envelope of techniques, and expand the meaning of well-behaved for a given context. G. H. Hardy wrote that "The problem of deciding whether two given limit operations are commutative is one of the most importan
|
https://en.wikipedia.org/wiki/Pullback%20attractor
|
In mathematics, the attractor of a random dynamical system may be loosely thought of as a set to which the system evolves after a long enough time. The basic idea is the same as for a deterministic dynamical system, but requires careful treatment because random dynamical systems are necessarily non-autonomous. This requires one to consider the notion of a pullback attractor or attractor in the pullback sense.
Set-up and motivation
Consider a random dynamical system on a complete separable metric space , where the noise is chosen from a probability space with base flow .
A naïve definition of an attractor for this random dynamical system would be to require that for any initial condition , as . This definition is far too limited, especially in dimensions higher than one. A more plausible definition, modelled on the idea of an omega-limit set, would be to say that a point lies in the attractor if and only if there exists an initial condition, , and there is a sequence of times such that
as .
This is not too far from a working definition. However, we have not yet considered the effect of the noise , which makes the system non-autonomous (i.e. it depends explicitly on time). For technical reasons, it becomes necessary to do the following: instead of looking seconds into the "future", and considering the limit as , one "rewinds" the noise seconds into the "past", and evolves the system through seconds using the same initial condition. That is, one is interested in
|
https://en.wikipedia.org/wiki/Pfister%20form
|
In mathematics, a Pfister form is a particular kind of quadratic form, introduced by Albrecht Pfister in 1965. In what follows, quadratic forms are considered over a field F of characteristic not 2. For a natural number n, an n-fold Pfister form over F is a quadratic form of dimension 2n that can be written as a tensor product of quadratic forms
for some nonzero elements a1, ..., an of F. (Some authors omit the signs in this definition; the notation here simplifies the relation to Milnor K-theory, discussed below.) An n-fold Pfister form can also be constructed inductively from an (n−1)-fold Pfister form q and a nonzero element a of F, as .
So the 1-fold and 2-fold Pfister forms look like:
.
For n ≤ 3, the n-fold Pfister forms are norm forms of composition algebras. In that case, two n-fold Pfister forms are isomorphic if and only if the corresponding composition algebras are isomorphic. In particular, this gives the classification of octonion algebras.
The n-fold Pfister forms additively generate the n-th power I n of the fundamental ideal of the Witt ring of F.
Characterizations
A quadratic form q over a field F is multiplicative if, for vectors of indeterminates x and y, we can write q(x).q(y) = q(z) for some vector z of rational functions in the x and y over F. Isotropic quadratic forms are multiplicative. For anisotropic quadratic forms, Pfister forms are multiplicative, and conversely.
For n-fold Pfister forms with n ≤ 3, this had been known since the 19th ce
|
https://en.wikipedia.org/wiki/Norm%20form
|
In mathematics, a norm form is a homogeneous form in n variables constructed from the field norm of a field extension L/K of degree n. That is, writing N for the norm mapping to K, and selecting a basis e1, ..., en for L as a vector space over K, the form is given by
N(x1e1 + ... + xnen)
in variables x1, ..., xn.
In number theory norm forms are studied as Diophantine equations, where they generalize, for example, the Pell equation. For this application the field K is usually the rational number field, the field L is an algebraic number field, and the basis is taken of some order in the ring of integers OL of L.
See also
Trace form
References
Field (mathematics)
Diophantine equations
Homogeneous polynomials
|
https://en.wikipedia.org/wiki/Base%20flow%20%28random%20dynamical%20systems%29
|
In mathematics, the base flow of a random dynamical system is the dynamical system defined on the "noise" probability space that describes how to "fast forward" or "rewind" the noise when one wishes to change the time at which one "starts" the random dynamical system.
Definition
In the definition of a random dynamical system, one is given a family of maps on a probability space . The measure-preserving dynamical system is known as the base flow of the random dynamical system. The maps are often known as shift maps since they "shift" time. The base flow is often ergodic.
The parameter may be chosen to run over
(a two-sided continuous-time dynamical system);
(a one-sided continuous-time dynamical system);
(a two-sided discrete-time dynamical system);
(a one-sided discrete-time dynamical system).
Each map is required
to be a -measurable function: for all ,
to preserve the measure : for all , .
Furthermore, as a family, the maps satisfy the relations
, the identity function on ;
for all and for which the three maps in this expression are defined. In particular, if exists.
In other words, the maps form a commutative monoid (in the cases and ) or a commutative group (in the cases and ).
Example
In the case of random dynamical system driven by a Wiener process , where is the two-sided classical Wiener space, the base flow would be given by
.
This can be read as saying that "starts the noise at time instead of time 0".
Random dynamical systems
|
https://en.wikipedia.org/wiki/Norm%20variety
|
In mathematics, a norm variety is a particular type of algebraic variety V over a field F, introduced for the purposes of algebraic K-theory by Voevodsky. The idea is to relate Milnor K-theory of F to geometric objects V, having function fields F(V) that 'split' given 'symbols' (elements of Milnor K-groups).
The formulation is that p is a given prime number, different from the characteristic of F, and a symbol is the class mod p of an element
of the n-th Milnor K-group. A field extension is said to split the symbol, if its image in the K-group for that field is 0.
The conditions on a norm variety V are that V is irreducible and a non-singular complete variety. Further it should have dimension d equal to
The key condition is in terms of the d-th Newton polynomial sd, evaluated on the (algebraic) total Chern class of the tangent bundle of V. This number
should not be divisible by p2, it being known it is divisible by p.
Examples
These include (n = 2) cases of the Severi–Brauer variety and (p = 2) Pfister forms. There is an existence theorem in the general case (paper of Markus Rost cited).
References
External links
Paper by Rost
Algebraic varieties
K-theory
|
https://en.wikipedia.org/wiki/Absorbing%20set%20%28random%20dynamical%20systems%29
|
In mathematics, an absorbing set for a random dynamical system is a subset of the phase space. A dynamical system is a system in which a function describes the time dependence of a point in a geometrical space.
The absorbing set eventually contains the image of any bounded set under the cocycle ("flow") of the random dynamical system. As with many concepts related to random dynamical systems, it is defined in the pullback sense.
Definition
Consider a random dynamical system φ on a complete separable metric space (X, d), where the noise is chosen from a probability space (Ω, Σ, P) with base flow θ : R × Ω → Ω. A random compact set K : Ω → 2X is said to be absorbing if, for all d-bounded deterministic sets B ⊆ X, there exists a (finite) random time τB : Ω → 0, +∞) such that
This is a definition in the pullback sense, as indicated by the use of the negative time shift θ−t.
See also
Glossary of areas of mathematics
Lists of mathematics topics
Mathematics Subject Classification
Outline of mathematics
References
(See footnote (e) on p. 104)
Random dynamical systems
|
https://en.wikipedia.org/wiki/Discrete%20series%20representation
|
In mathematics, a discrete series representation is an irreducible unitary representation of a locally compact topological group G that is a subrepresentation of the left regular representation of G on L²(G). In the Plancherel measure, such representations have positive measure. The name comes from the fact that they are exactly the representations that occur discretely in the decomposition of the regular representation.
Properties
If G is unimodular, an irreducible unitary representation ρ of G is in the discrete series if and only if one (and hence all) matrix coefficient
with v, w non-zero vectors is square-integrable on G, with respect to Haar measure.
When G is unimodular, the discrete series representation has a formal dimension d, with the property that
for v, w, x, y in the representation. When G is compact this coincides with the dimension when the Haar measure on G is normalized so that G has measure 1.
Semisimple groups
classified the discrete series representations of connected semisimple groups G. In particular, such a group has discrete series representations if and only if it has the same rank as a maximal compact subgroup K. In other words, a maximal torus T in K must be a Cartan subgroup in G. (This result required that the center of G be finite, ruling out groups such as the simply connected cover of SL(2,R).) It applies in particular to special linear groups; of these only SL(2,R) has a discrete series (for this, see the representation theory of S
|
https://en.wikipedia.org/wiki/It%C3%B4%20isometry
|
In mathematics, the Itô isometry, named after Kiyoshi Itô, is a crucial fact about Itô stochastic integrals. One of its main applications is to enable the computation of variances for random variables that are given as Itô integrals.
Let denote the canonical real-valued Wiener process defined up to time , and let be a stochastic process that is adapted to the natural filtration of the Wiener process. Then
where denotes expectation with respect to classical Wiener measure.
In other words, the Itô integral, as a function from the space of square-integrable adapted processes to the space of square-integrable random variables, is an isometry of normed vector spaces with respect to the norms induced by the inner products
and
As a consequence, the Itô integral respects these inner products as well, i.e. we can write
for .
References
Stochastic calculus
|
https://en.wikipedia.org/wiki/Functional%20square%20root
|
In mathematics, a functional square root (sometimes called a half iterate) is a square root of a function with respect to the operation of function composition. In other words, a functional square root of a function is a function satisfying for all .
Notation
Notations expressing that is a functional square root of are and .
History
The functional square root of the exponential function (now known as a half-exponential function) was studied by Hellmuth Kneser in 1950.
The solutions of over (the involutions of the real numbers) were first studied by Charles Babbage in 1815, and this equation is called Babbage's functional equation. A particular solution is for . Babbage noted that for any given solution , its functional conjugate by an arbitrary invertible function is also a solution. In other words, the group of all invertible functions on the real line acts on the subset consisting of solutions to Babbage's functional equation by conjugation.
Solutions
A systematic procedure to produce arbitrary functional -roots (including arbitrary real, negative, and infinitesimal ) of functions relies on the solutions of Schröder's equation. Infinitely many trivial solutions exist when the domain of a root function f is allowed to be sufficiently larger than that of g.
Examples
is a functional square root of .
A functional square root of the th Chebyshev polynomial, , is , which in general is not a polynomial.
is a functional square root of .
[red curve]
[blue
|
https://en.wikipedia.org/wiki/Ira%20Carmen
|
Ira Harris Carmen (born December 3, 1934) graduated from the University of Michigan and is an American Professor Emeritus of Political Science at the University of Illinois at Urbana-Champaign, where he taught from 1968 to 2009.
Carmen is a co-founder of the social science subdiscipline of genetics and politics. The first political scientist to be elected to the Human Genome Organization, he is a member of two research teams at the University of Illinois, one exploring sociogenomics and the other stem cell research.
After 41 years of service, Professor Carmen retired on August 24, 2009.
Research
Cloning and the Constitution: An Inquiry into Governmental Policymaking and Genetic Experimentation
Politics in the Laboratory: The Constitution of Human Genomics
Power & Balance: An Introduction to American Constitutional Government
Movies, Censorship, and the Law
References
External links
The Constitution of Human Genomics
1934 births
Living people
University of Michigan alumni
University of Illinois Urbana-Champaign faculty
American political scientists
|
https://en.wikipedia.org/wiki/International%20Young%20Physicists%27%20Tournament
|
The International Young Physicists' Tournament (IYPT), sometimes referred to as the “Physics World Cup”, is a scientific competition between teams of secondary school students. It mimics, as close as possible, the real-world scientific research and the process of presenting and defending the results obtained.
Participants have almost a year to work on 17 open-ended inquiry problems that are published yearly in late July. A good part of the problems involves easy-to-reproduce phenomena presenting unexpected behaviour. The aim of the solutions is not to calculate or reach “the correct answer” as there is no such notion here. The Tournament is rather conclusions-oriented as participants have to design and perform experiments, and to draw conclusions argued from the experiments’ outcome.
The competition itself is not a pen-and-paper competition but an enactment of a scientific discussion (or a defence of a thesis) where participants take the roles of Reporter, Opponent and Reviewer, thus learning about peer review early on in their school years. Discussion-based sessions are called Physics Fights and the performances of the teams are judged by expert physicists.
Teams can take quite different routes to tackle the same problem. As long as they stay within the broadly defined statement of the problem, all routes are legitimate and teams will be judged according to the depths reached by their investigations.
The IYPT is a week-long event in which currently around 150 internation
|
https://en.wikipedia.org/wiki/Kay%20Toliver
|
Kay Toliver is a teacher specialising in mathematics education.
Background
Kay Toliver was born and raised in East Harlem and the South Bronx. A product of the New York City public school system, she graduated from Harriet Beecher Stowe Junior High, Walton High School and Hunter College (AB 1967, MA 1971) with graduate work at the City College of New York in mathematics.
For more than 30 years, Kay Toliver taught mathematics and communication arts at P.S. 72/East Harlem Tech in Community School District 4. Prior to instructing seventh and eighth grade students, she taught grades one through six for 15 years.
"Becoming a teacher was the fulfillment of a childhood dream. My parents always stressed that education was the key to a better life. By becoming a teacher, I hoped to inspire African-American and Hispanic youths to realize their own dreams. I wanted to give something back to the communities I grew up in."
At East Harlem Tech, with the support of her principal, she established the "Challenger" program. The program, for grades 4-8, presents the basics of geometry and algebra in an integrated curriculum. This is a program for "gifted" students, but following her belief that all children can learn, she accepted students from all ability levels.
Teaching methods
The Math Fair
These events are similar to science fairs but involve students in creating and displaying projects relating to mathematics. Participants had to be able to explain thoroughly the mathematical the
|
https://en.wikipedia.org/wiki/Avishai%20Dekel
|
Avishai Dekel (born 1951) is a professor of physics at the Hebrew University of Jerusalem, Israel, holding the Andre Aisenstadt Chair of Theoretical Physics. His primary research interests are in astrophysics and cosmology.
Academic career
Dekel earned his Ph.D. from the Hebrew University in 1980, and was a research fellow at Caltech and assistant professor at Yale University before joining the faculty of the Hebrew University in 1986.
He served as the Head of The Racah Institute of Physics (1997–2001), the Dean of the Authority for the Community and Youth at the Hebrew University (2005–2011), and the President of the Israel Physical Society (2008–11). He headed the university computing committee, was a member of the executive committee of the board of trustees and a member of the standing committee of the Hebrew University.
Dekel was awarded a Visiting Miller Professorship at UC Berkeley, a Blaise Pascal International Chair of Research by the École Normale Supérieure in Paris (2004–06), and a Lagrange fellowship in IAP Paris (2015–16). He has been elected as a fellow of the Israel Physical Society (2019), and has been awarded the Landau Prize for Arts and Sciences (2020).
Dekel is known for his contributions to research in cosmology, especially the study of the formation of galaxies and large-scale structure in the Universe, which is dominated by dark energy and dark matter.
His expertise is dwarf galaxies and supernova feedback (1986, 2003), large-scale cosmic flows
|
https://en.wikipedia.org/wiki/Integral%20cryptanalysis
|
In cryptography, integral cryptanalysis is a cryptanalytic attack that is particularly applicable to block ciphers based on substitution–permutation networks. It was originally designed by Lars Knudsen as a dedicated attack against Square, so it is commonly known as the Square attack. It was also extended to a few other ciphers related to Square: CRYPTON, Rijndael, and SHARK. Stefan Lucks generalized the attack to what he called a saturation attack and used it to attack Twofish, which is not at all similar to Square, having a radically different Feistel network structure. Forms of integral cryptanalysis have since been applied to a variety of ciphers, including Hierocrypt, IDEA, Camellia, Skipjack, MISTY1, MISTY2, SAFER++, KHAZAD, and FOX (now called IDEA NXT).
Unlike differential cryptanalysis, which uses pairs of chosen plaintexts with a fixed XOR difference, integral cryptanalysis uses sets or even multisets of chosen plaintexts of which part is held constant, and another part varies through all possibilities. For example, an attack might use 256 chosen plaintexts that have all but 8 of their bits the same, but all differ in those 8 bits. Such a set necessarily has an XOR sum of 0, and the XOR sums of the corresponding sets of ciphertexts provide information about the cipher's operation. This contrast between the differences of pairs of texts and the sums of larger sets of texts inspired the name "integral cryptanalysis", borrowing the terminology of calculus.
Reference
|
https://en.wikipedia.org/wiki/Norman%20Matloff
|
Norman Saul Matloff (born December 16, 1948) is an American professor of computer science at the University of California, Davis.
Early life
Norman Saul Matloff was born on December 16, 1948. Matloff received his Doctor of Philosophy degree in 1975 from the mathematics department at the University of California, Los Angeles under the supervision of Thomas M. Liggett. His dissertation was titled Equilibrium Behavior in an Infinite Voting Model.
Career
Matloff is the author of several books on computer science, statistics and programming, including
The Art of R Programming
The Art of Debugging with GDB, DDD and Eclipse
Parallel Computing for Data Science: With Examples in R, C++ and Cuda
Fast Lane to Python: A Quick, Sensible Route to the Joys of Python Coding
Probability and Statistics for Data Science: Math + R + Data
Statistical Regression and Classification: From Linear Models to Machine Learning
Regression and Classification in R: A Careful, Thus Practical View
Matloff is also the author of many articles concerning machine learning, parallel computing and recommender systems. His just under 2000 citations amount to an h-index of 22.
Matloff also writes a blog. He views the increased use of H-1B visas in the high technology field as an unnecessary practice that harms the prospects of Americans in the field, and was featured in local American media on this topic. Gawker published an article on him "UC professor injects racism into H-1B debate"
Matloff previousl
|
https://en.wikipedia.org/wiki/Cosimo%20Matassa
|
Cosimo Vincent Matassa (April 13, 1926 – September 11, 2014) was an American recording engineer and studio owner, responsible for many R&B and early rock and roll recordings.
Life and career
Matassa was born in New Orleans in 1926. In 1944 he began studies as a chemistry major at Tulane University, which he abandoned after completing five semesters of course work. In 1945, at the age of 18, Matassa opened the J&M Recording Studio at the back of his family's shop on Rampart Street, on the border of the French Quarter in New Orleans. In 1955, he moved to the larger Cosimo Recording Studio on Gov. Nichols Street, nearby in the French Quarter.
As an engineer and proprietor, Matassa was crucial to the development of the sound of R&B, rock and soul of the 1950s and 1960s, often working with the producers Dave Bartholomew and Allen Toussaint. He recorded many hits, including Fats Domino’s "The Fat Man" (a contender for the first rock and roll record), Little Richard's "Tutti Frutti", and records by Ray Charles, Lee Dorsey, Dr. John, Smiley Lewis, Bobby Mitchell, Tommy Ridgley, the Spiders and many others. He was responsible for developing what became known as the New Orleans sound, with strong drums, heavy guitar and bass, heavy piano, light horns and a strong vocal lead. In the late 1950s and early 1960s, Matassa also managed the successful white New Orleans rock-and-roll performer Jimmy Clanton.
Matassa is interviewed on screen in the 2005 documentary film Make It Funky!, whic
|
https://en.wikipedia.org/wiki/Nozomu%20Sahashi
|
; previously Saruhashi) is the founder of the now-defunct Nova Corporation, previously the major eikaiwa (private school for conversational English) provider in Japan. After graduating from high school, Sahashi went to Paris to attend university and majored in physics although it took him five years to complete a two-year course. The award status of his degree is unknown.
Nova
Founding
Sahashi was born and raised in Kishiwada, Osaka. He spent several years jobless after returning from France before founding Nova in 1981 with two foreign English teachers. He is the inventor of Nova's particular teaching method, "The NOVA System Concept", which he patented. The Concept is perhaps most comparable to the direct method of language instruction, although Sahashi's method pivots on the interaction with and the repeating of an instructor who was a native speaker. Sahashi thought a native speaker's voice would alleviate the difficulty of the average Japanese brain to distinguish English from background noise, as Japanese and English languages evoked different brain wave patterns. Sahashi had also patented a video phone camera device, a telephone interpretation (translation) system and an at-home medical examination system which provides a virtual consultation room, a virtual waiting room, a virtual nursing room and a virtual individual conversation room depending upon the desired operation although the system does not provide for actual treatment.
Financial crisis and downfall
Sahas
|
https://en.wikipedia.org/wiki/Enriched%20Xenon%20Observatory
|
The Enriched Xenon Observatory (EXO) is a particle physics experiment searching for neutrinoless double beta decay of xenon-136 at WIPP near Carlsbad, New Mexico, U.S.
Neutrinoless double beta decay (0νββ) detection would prove the Majorana nature of neutrinos and impact the neutrino mass values and ordering. These are important open topics in particle physics.
EXO currently has a 200-kilogram xenon liquid time projection chamber (EXO-200) with R&D efforts on a ton-scale experiment (nEXO). Xenon double beta decay was detected and limits have been set for 0νββ.
Overview
EXO measures the rate of neutrinoless decay events above the expected background of similar signals, to find or limit the double beta decay half-life, which relates to the effective neutrino mass using nuclear matrix elements. A limit on effective neutrino mass below 0.01 eV would determine the neutrino mass order. The effective neutrino mass is dependent on the lightest neutrino mass in such a way that that bound indicates the normal mass hierarchy.
The expected rate of 0νββ events is very low, so background radiation is a significant problem. WIPP has of rock overburden—equivalent to of water—to screen incoming cosmic rays. Lead shielding and a cryostat also protect the setup. The neutrinoless decays would appear as narrow spike in the energy spectrum around the xenon Q-value (Qββ = 2457.8 keV), which is fairly high and above most gamma decays.
EXO-200
History
EXO-200 was designed with a goal
|
https://en.wikipedia.org/wiki/John%20Cairns%20%28biochemist%29
|
Hugh John Forster Cairns FRS (21 November 1922 – 12 November 2018) was a British physician and molecular biologist who made significant contributions to molecular genetics, cancer research, and public health.
Career
Cairns received his M.D. from Oxford. He then worked as a virologist at the Walter and Eliza Hall Institute of Medical Research in Melbourne, Australia and at the Virus Research Institute at Entebbe, Uganda. He returned to Australia to work in the School of Microbiology at the John Curtin School of Medical Research. Cairns took a sabbatical to research at the Cold Spring Harbor Laboratory between 1960 and 1961, and returned there to serve as the director from 1963 to 1968. He remained a staff member at Cold Spring Harbor until 1972, when he was appointed head of the Mill Hill Laboratory of the Imperial Cancer Research Fund. After leaving Mill Hill in 1980, he took up a professorship at the Harvard School of Public Health. He retired in 1991.
In his 1963 paper "The bacterial chromosome and its manner of replication as seen by autoradiography", Cairns demonstrated by autoradiography that the DNA of the bacterium Escherichia coli was a single molecule that is replicated at a moving locus (the replicating fork) at which both new DNA strands are being synthesized. Subsequently, it was found that there were in fact two moving forks, traveling simultaneously in opposite directions around the chromosome.
In 1974 he was elected Fellow of the Royal Society. In 1981, Joh
|
https://en.wikipedia.org/wiki/Journal%20of%20High%20Energy%20Physics
|
The Journal of High Energy Physics is a monthly peer-reviewed open access scientific journal covering the field of high energy physics. It is published by Springer Science+Business Media on behalf of the International School for Advanced Studies. The journal is part of the SCOAP3 initiative. According to the Journal Citation Reports, the journal has a 2020 impact factor of 5.810.
References
External links
Journal page at International School for Advanced Studies website
English-language journals
Monthly journals
Physics journals
Academic journals established in 1997
Springer Science+Business Media academic journals
Academic journals associated with learned and professional societies
Particle physics journals
|
https://en.wikipedia.org/wiki/Harmonic%20coordinates
|
In Riemannian geometry, a branch of mathematics, harmonic coordinates are a certain kind of coordinate chart on a smooth manifold, determined by a Riemannian metric on the manifold. They are useful in many problems of geometric analysis due to their regularity properties.
In two dimensions, certain harmonic coordinates known as isothermal coordinates have been studied since the early 1800s. Harmonic coordinates in higher dimensions were developed initially in the context of Lorentzian geometry and general relativity by Albert Einstein and Cornelius Lanczos (see harmonic coordinate condition). Following the work of Dennis DeTurck and Jerry Kazdan in 1981, they began to play a significant role in the geometric analysis literature, although Idzhad Sabitov and S.Z. Šefel had made the same discovery five years earlier.
Definition
Let be a Riemannian manifold of dimension . One says that a coordinate chart , defined on an open subset of , is harmonic if each individual coordinate function is a harmonic function on . That is, one requires that
where is the Laplace–Beltrami operator. Trivially, the coordinate system is harmonic if and only if, as a map , the coordinates are a harmonic map. A direct computation with the local definition of the Laplace-Beltrami operator shows that is a harmonic coordinate chart if and only if
in which are the Christoffel symbols of the given chart. Relative to a fixed "background" coordinate chart , one can view as a collection of functions
|
https://en.wikipedia.org/wiki/Mario%20Ageno
|
Mario Ageno (March 2, 1915 – December 23, 1992) is considered one of Italy's most important biophysicists.
Early life and education
Born in Livorno from a Genoese family, he studied Physics for two years in Genoa, when one of his professors noticed his talent as a scientist, and suggested that he should move to Rome. He did, and from 1934 started collaborating with the "Via Panisperna boys" on nuclear physics and cosmic rays; the former became the subject of his graduation thesis under the supervision of Enrico Fermi, in 1936. He was one of the last Italian students to study under Fermi before Fermi emigrated to the United States. In 1938 he was recruited to work with Edoardo Amaldi on the first Italian particle accelerator.
Career
Aged 21, Ageno was selected to work with the "Via Panisperna boys" during their final years; when World War II broke out, he was drafted and fought in Libya. In 1949, he moved to the Physics department at the Istituto Superiore di Sanità, under the direction of Giulio Trabacchi, whom he succeeded in the position of head of department in 1959. With the collaboration of Franco Graziosi, he devoted the activities of the department to biophysics.
Thanks to his collaboration with Adriano Buzzati-Traverso, Ageno taught at the University of Pavia in 1960–1961, and became a member of the first scientific council of Traverso's Laboratorio Internazionale di Genetica e Biofisica. He left the Istituto Superiore di Sanità for the University of Rome La Sapien
|
https://en.wikipedia.org/wiki/List%20of%20things%20named%20after%20Hermann%20Weyl
|
This is a list of topics named after Hermann Weyl, the influential German mathematician from the 20th century.
Mathematics and physics
Cartan–Weyl theory
Cartan–Weyl basis
Courant–Fischer–Weyl min-max principle
De Donder–Weyl theory
Hodge−Weyl decomposition
Majorana–Weyl spinor
Peter–Weyl theorem
Schur–Weyl duality
Weyl–Berry conjecture
Weyl–Groenewold product
Wigner–Weyl transform
Weyl algebra
Weyl almost periodic functions
Weyl anomaly
Weyl basis of the gamma matrices
Weyl chamber
Weyl character formula
Weyl denominator formula
Weyl dimension formula
Weyl–Kac character formula
Weyl curvature: see Weyl tensor
Weyl curvature hypothesis
Weyl dimension formula, a specialization of the character formula
Weyl distance function
Weyl equation, a relativistic wave equation
Weyl expansion
Weyl fermion
Weyl gauge
Weyl gravity
Weyl group
Length of a Weyl group element
Restricted Weyl group
Weyl integral
Weyl integration formula
Weyl law
Weyl metrics
Weyl module
Weyl notation
Weyl quantization
Weyl relations
Weyl scalar
Weyl semimetal
Weyl sequence
Weyl spinor
Weyl representation
Weyl sum, a type of exponential sum
Weyl symmetry: see Weyl transformation
Weyl tensor
Weyl transform
Weyl transformation
Weyl vector of a compact Lie group
Weyl–Brauer matrices
Weyl−Lewis−Papapetrou coordinates
Weyl–Schouten theorem
Weyl–von Neumann theorem
Weyl-squared theories
Weyl's axioms
Weyl's construction
Weyl's criterion
Weyl's criterion for ess
|
https://en.wikipedia.org/wiki/Karl%20Stein%20%28mathematician%29
|
Karl Stein (1 January 1913 in Hamm, Westphalia – 19 October 2000) was a German mathematician. He is well known for complex analysis and cryptography. Stein manifolds and Stein factorization are named after him.
Career
Karl Stein received his doctorate with his dissertation on the topic Zur Theorie der Funktionen mehrerer komplexer Veränderlichen; Die Regularitätshüllen niederdimensionaler Mannigfaltigkeiten at the University of Münster under the supervision of Heinrich Behnke in 1937. Karl Stein was conscripted into the Wehrmacht sometime before 1942, and trained as a cryptographer to work at OKW/Chi, the Cipher Department of the High Command of the Wehrmacht. He was assigned to manage the OKW/Chi IV, Subsection a, which was a unit responsible for security of own processes, cipher devices testing, and invention of new cipher devices. He managed a staff of 11 In 1955 he became professor at the Ludwig Maximilian University of Munich and emeritated in 1981. In 1990 he received the first Cantor medal.
Students
Stein's doctoral students included , Otto Forster, , Gunther Schmidt and Martin Schottenloher.
References
1913 births
2000 deaths
People from Hamm
20th-century German mathematicians
University of Münster alumni
Academic staff of the Ludwig Maximilian University of Munich
German cryptographers
|
https://en.wikipedia.org/wiki/Semipermutable%20subgroup
|
In mathematics, in algebra, in the realm of group theory, a subgroup of a finite group is said to be semipermutable if commutes with every subgroup whose order is relatively prime to that of .
Clearly, every permutable subgroup of a finite group is semipermutable. The converse, however, is not necessarily true.
External links
The Influence of semipermutable subgroups on the structure of finite groups
Subgroup properties
|
https://en.wikipedia.org/wiki/Aurophilicity
|
In chemistry, aurophilicity refers to the tendency of gold complexes to aggregate via formation of weak metallophilic interactions.
The main evidence for aurophilicity is from the crystallographic analysis of Au(I) complexes. The aurophilic bond has a length of about 3.0 Å and a strength of about 7–12 kcal/mol, which is comparable to the strength of a hydrogen bond. The effect is greatest for gold as compared with copper or silver—the higher elements in its periodic table group—due to increased relativistic effects. Observations and theory show that, on average, 28% of the binding energy in the aurophilic interaction can be attributed to relativistic expansion of the gold d orbitals.
An example of aurophilicity is the propensity of gold centres to aggregate. While both intramolecular and intermolecular aurophilic interactions have been observed, only intramolecular aggregation has been observed at such nucleation sites.
Role in self-assembly
The similarity in strength between hydrogen bonding and aurophilic interaction has proven to be a convenient tool in the field of polymer chemistry. Much research has been conducted on self-assembling supramolecular structures, both those that aggregate by aurophilicity alone and those that contain both aurophilic and hydrogen-bonding interactions. An important and exploitable property of aurophilic interactions relevant to their supramolecular chemistry is that while both inter- and intramolecular interactions are possible, inter
|
https://en.wikipedia.org/wiki/Sankar%20Ghosh
|
Sankar Ghosh is an Indian-American immunologist, microbiologist, and biochemist, who is the Chair and Silverstein & Hutt Family Professor of the Department of Microbiology & Immunology at Columbia University Irving Medical Center. Ghosh is best known for his pioneering research on the activation of cellular responses via NF-κB, a transcription factor that plays a critical role in regulating the expression of a large number of genes involved in the mammalian immune system. Ghosh's research led to the first cloning and characterization of NF-κB and IkB proteins, including the demonstration of the role of IkB phosphorylation in the activation of NF-κB.
Over the years, Ghosh's research has been prominently published in numerous leading scientific journals. Ghosh was elected to the American Academy of Arts & Sciences in 2023, to the National Academy of Medicine in 2022, and the National Academy of Sciences in 2021. He previously was elected a Fellow of the American Association for the Advancement of Science in 2007 for his "distinguished contributions to the field of immunology, particularly for studies of the NF-kB signaling pathway."
Education
Ghosh received his Ph.D. in Molecular Biology from the Albert Einstein College of Medicine in 1988. He then did his postdoctoral research training with Nobel Laureate Dr. David Baltimore at the Whitehead Institute at MIT in Cambridge, MA. Ghosh previously received his B.Sc. and M.Sc. degrees from Calcutta University in India.
While in B
|
https://en.wikipedia.org/wiki/Bundle%20map
|
In mathematics, a bundle map (or bundle morphism) is a morphism in the category of fiber bundles. There are two distinct, but closely related, notions of bundle map, depending on whether the fiber bundles in question have a common base space. There are also several variations on the basic theme, depending on precisely which category of fiber bundles is under consideration. In the first three sections, we will consider general fiber bundles in the category of topological spaces. Then in the fourth section, some other examples will be given.
Bundle maps over a common base
Let and be fiber bundles over a space M. Then a bundle map from E to F over M is a continuous map such that . That is, the diagram
should commute. Equivalently, for any point x in M, maps the fiber of E over x to the fiber of F over x.
General morphisms of fiber bundles
Let πE:E→ M and πF:F→ N be fiber bundles over spaces M and N respectively. Then a continuous map is called a bundle map from E to F if there is a continuous map f:M→ N such that the diagram
commutes, that is, . In other words, is fiber-preserving, and f is the induced map on the space of fibers of E: since πE is surjective, f is uniquely determined by . For a given f, such a bundle map is said to be a bundle map covering f.
Relation between the two notions
It follows immediately from the definitions that a bundle map over M (in the first sense) is the same thing as a bundle map covering the identity map of M.
Conversely, general
|
https://en.wikipedia.org/wiki/Sabba%20S.%20%C8%98tef%C4%83nescu
|
Sabba S. Ștefănescu (20 July 1902 – 15 April 1994) was a Romanian geophysicist, professor of geophysics, member of the Romanian Academy. He was the cofounder, together with Liviu Constantinescu, of the Romanian school of geophysics.
Biography
He was the third and youngest son of , professor of paleontology at the University of Bucharest, and of his wife Constanța. He received at first a private education, then attended for a couple of years the Saint Sava College in Bucharest, but left the country together with his family in 1917 for Paris, where his father had to accomplish a diplomatic mission. He obtained there his baccalauréat at the Lycée Saint-Louis and was admitted as a student at the prestigious École des Mines, from which he graduated in 1923. He returned subsequently to Romania, where he worked for some time in the mining district of the Jiu Valley. In 1927 he joined the , where he began his studies in electrical prospecting, which was to remain his lifelong preoccupation.
Two short papers of his drew the attention of the brothers Conrad and Marcel Schlumberger. They were at that time the pioneers of this field in Europe and had just founded the geophysical prospecting company bearing their name, which has developed since into the world leading Schlumberger Limited. Ștefănescu entered into a direct collaboration with them and spent the years 1929–1933 in Paris, a period which he considered to be the most fruitful of his scientific life. He returned to Romania in
|
https://en.wikipedia.org/wiki/Tannakian%20formalism
|
In mathematics, a Tannakian category is a particular kind of monoidal category C, equipped with some extra structure relative to a given field K. The role of such categories C is to approximate, in some sense, the category of linear representations of an algebraic group G defined over K. A number of major applications of the theory have been made, or might be made in pursuit of some of the central conjectures of contemporary algebraic geometry and number theory.
The name is taken from Tadao Tannaka and Tannaka–Krein duality, a theory about compact groups G and their representation theory. The theory was developed first in the school of Alexander Grothendieck. It was later reconsidered by Pierre Deligne, and some simplifications made. The pattern of the theory is that of Grothendieck's Galois theory, which is a theory about finite permutation representations of groups G which are profinite groups.
The gist of the theory is that the fiber functor Φ of the Galois theory is replaced by a tensor functor T from C to K-Vect. The group of natural transformations of Φ to itself, which turns out to be a profinite group in the Galois theory, is replaced by the group (a priori only a monoid) of natural transformations of T into itself, that respect the tensor structure. This is by nature not an algebraic group, but an inverse limit of algebraic groups (pro-algebraic group).
Formal definition
A neutral Tannakian category is a rigid abelian tensor category, such that there exists a K-t
|
https://en.wikipedia.org/wiki/Isaac%20Charles%20Johnson
|
Isaac Charles Johnson (28 January 1811 – 29 November 1911) was a British cement manufacturer, and a pioneer of the Portland cement industry.
Born in London, his father was a charge-hand at Francis & White's "Roman Cement" plant in Nine Elms. He himself worked there as a labourer from age 16 while studying chemistry. In 1833 he became manager of John Bazeley White's cement plant at Swanscombe on the Thames Estuary which at that time was producing "Artificial Cement" and "Roman Cement". Joseph Aspdin's product was successful but very expensive, and was later improved independently by his son William. Johnson set to work trying to discover its composition but because Aspdin's product was protected by explicit patents and extreme secrecy it was impossible to market a copy. After nearly two years' work, he succeeded and started marketing his own considerably improved version.
Johnson, a highly moral man, Mayor of Gateshead and a JP, was able to claim that he was the inventor of "true" Portland cement and is generally recognised as such. Aspdin, however, was driven out of business by financial problems caused by the success of Johnson's superior and cheaper product and this led to Johnson taking over Aspdins Cement works at Gateshead, County Durham. Unfortunately this resulted in an embittered Aspdin making wild and vitriolic charges of how his product had been copied. Johnson left J.B. White's shortly afterwards, and, setting up his own company, established a succession of ceme
|
https://en.wikipedia.org/wiki/Xpand%20Rally
|
Xpand Rally is a rally racing game developed by Techland for Microsoft Windows. The games main focus is on graphics as well as physics. It contains 60 tracks where players can drive against 120 different rally drivers.
Reception
The game received "favorable" reviews according to the review aggregation website Metacritic.
Xpand Rally Xtreme
Xpand Rally Xtreme is the sequel to Xpand Rally which was released on December 1, 2006.
Xpand Rally Xtreme contains similar content to the original Xpand Rally. In-game, apart from well-known rally cars, players find GT vehicles, DTR group buggies, and off-road 4x4 cars and Monster Trucks vehicle groups. The game also presents about 40 tracks in typical SS contests, off-road cross-country rides, and track races against new opponents.
Like the original Xpand Rally, the game contains career, single race and multiplayer modes. It is based on the Chrome Engine and players can use the Chromed editor to create their own tracks and game modes.
References
External links
Techland Website (English)
2004 video games
2006 video games
Off-road racing video games
Rally racing video games
Video games set in Arizona
Video games set in Finland
Video games set in Ireland
Video games set in Kenya
Video games set in Poland
Video games developed in Poland
Video games developed in the United States
Windows games
Windows-only games
Multiplayer and single-player video games
Techland games
TopWare Interactive games
|
https://en.wikipedia.org/wiki/Watermarking%20attack
|
In cryptography, a watermarking attack is an attack on disk encryption methods where the presence of a specially crafted piece of data can be detected by an attacker without knowing the encryption key.
Problem description
Disk encryption suites generally operate on data in 512-byte sectors which are individually encrypted and decrypted. These 512-byte sectors alone can use any block cipher mode of operation (typically CBC), but since arbitrary sectors in the middle of the disk need to be accessible individually, they cannot depend on the contents of their preceding/succeeding sectors. Thus, with CBC, each sector has to have its own initialization vector (IV). If these IVs are predictable by an attacker (and the filesystem reliably starts file content at the same offset to the start of each sector, and files are likely to be largely contiguous), then there is a chosen plaintext attack which can reveal the existence of encrypted data.
The problem is analogous to that of using block ciphers in the electronic codebook (ECB) mode, but instead of whole blocks, only the first block in different sectors are identical. The problem can be relatively easily eliminated by making the IVs unpredictable with, for example, ESSIV.
Alternatively, one can use modes of operation specifically designed for disk encryption (see disk encryption theory). This weakness affected many disk encryption programs, including older versions of BestCrypt as well as the now-deprecated cryptoloop.
To carry
|
https://en.wikipedia.org/wiki/History%20of%20education%20in%20the%20Indian%20subcontinent
|
Education in the Indian subcontinent began with teaching of traditional elements such as Indian religions, Indian mathematics, Indian logic at early Hindu and Buddhist centres of learning such as ancient Takshashila (in modern-day Pakistan) and Nalanda (in India). Islamic education became ingrained with the establishment of Islamic empires in the Indian subcontinent in the Middle Ages while the coming of the Europeans later brought western education to colonial India.
Several Western-style universities were established during the period of British rule in the 19th century. A series of measures continuing throughout the early half of the 20th century ultimately laid the foundation of the educational system of the Republic of India, Pakistan and much of the Indian subcontinent.
Early history
Early education in India commenced under the supervision of a guru or prabhu. Initially, education was open to all and seen as one of the methods to achieve Moksha in those days, or enlightenment. As time progressed, due to a decentralised social structure, the education was imparted on the basis of varna and the related duties that one had to perform as a member of a specific caste. The Brahmans learned about scriptures and religion while the Kshatriya were educated in the various aspects of warfare. The Vaishya caste learned commerce and other specific vocational courses. The other caste Shudras, were men of working class and they were trained on skills to carry out these jobs. The ear
|
https://en.wikipedia.org/wiki/ECCB%20%28disambiguation%29
|
ECCB may refer to:
Monetary authority
Eastern Caribbean Central Bank, monetary authority of a group of eight Caribbean nations.
Scientific Conference
European Conference on Computational Biology, a scientific conference on Bioinformatics and Computational Biology
European Congress of Conservation Biology, a scientific conference on biodiversity and Conservation Biology
Religious denomination
Evangelical Church of Czech Brethren
|
https://en.wikipedia.org/wiki/Yoram%20Moses
|
Yoram Moses () is a Professor in the Electrical Engineering Department at the Technion - Israel Institute of Technology.
Yoram Moses received a B.Sc. in mathematics from the Hebrew University of Jerusalem in 1981, and a Ph.D. in Computer Science from Stanford University in 1986. Moses is a co-author of the book Reasoning About Knowledge, and is a winner of the 1997 Gödel Prize in theoretical computer science and the 2009 Dijkstra Prize in Distributed Computing.
His major research interests are distributed systems and reasoning about knowledge.
He is married to the computer scientist Yael Moses.
External links
Yoram Moses's homepage
Electrical engineering academics
Gödel Prize laureates
Dijkstra Prize laureates
Researchers in distributed computing
Hebrew University of Jerusalem alumni
Academic staff of Technion – Israel Institute of Technology
Stanford University alumni
Living people
Year of birth missing (living people)
Israeli electrical engineers
|
https://en.wikipedia.org/wiki/Balthazar%20Gerbier
|
Sir Balthazar Gerbier (23 February 1592, in N.S. – 1663) was an Anglo-Dutch courtier, diplomat, art advisor, miniaturist and architectural designer, in his own words fluent in "several languages" with "a good hand in writing, skill in sciences as mathematics, architecture, drawing, painting, contriving of scenes, masques, shows and entertainments for great Princes... as likewise for making of engines useful in war."
Biography
Gerbier, the son of Anthony Gerbier, was born in Middelburg, Zeeland, of a Huguenot family that had settled there. Dutch sources show that his family were cloth merchants although he claimed that his grandfather had been a "Baron Douvilly" and so signed himself on occasion.
As a designer of siege machinery he was recommended by Maurice of Nassau, later Prince of Orange, through whose efforts Gerbier arrived in London in 1616, in the train of the Dutch ambassador. In London he soon found a patron in George Villiers, 1st Duke of Buckingham for whom he found paintings and negotiated their purchase, acting in a sense as keeper of the Duke's collection, and for whom he painted miniatures and oversaw remodelling about 1625, at York House in the Strand and at New Hall, Essex (both since demolished). At York House and at New Hall, Gerbier was busy with architectural alterations for Buckingham, 1624-25. and ordered a wooden model of New Hall to be made for the Duke. At York House, a visit from Inigo Jones while the paving was being laid in the grande chambre r
|
https://en.wikipedia.org/wiki/CRYPTON
|
In cryptography, CRYPTON is a symmetric block cipher submitted as a candidate for the Advanced Encryption Standard (AES). It is very efficient in hardware implementations and was designed by Chae Hoon Lim of Future Systems Inc.
The CRYPTON algorithm processes blocks of 128 bits in the form of 4×4 byte arrays. The round transformation consists of four steps: byte-wise substitution, column-wise bit permutation, column-to-row transposition and finally key addition. CRYPTON uses 12 rounds of this encryption process. Due to the algorithm's nature, the decryption process can be made identical to the encryption process using a different key.
See also
AES process
External links
Hardware Design and Performance Estimation of The 128-bit Block Cipher CRYPTON by Eunjong Hong, Jai-Hoon Chung, Chae Hoon Lim
SCAN's entry for CRYPTON version 0.5 as originally submitted as AES candidate to NIST
CRYPTON: A New 128-bit Block Cipher - Specification and Analysis (Version 0.5) by Chae Hoon Lim, Hyo Sun Hwang
CRYPTON: A New 128-bit Block Cipher - Specification and Analysis (Version 1.0) by Chae Hoon Lim, Hyo Sun Hwang
Weak Keys of CRYPTON by Johan Borst, 28 Aug 1998. Response to call for comments on AES candidates. Retrieved 2014-01-23.
CRYPTON 1.0 Delphi implementation
Block ciphers
|
https://en.wikipedia.org/wiki/Kornblum%E2%80%93DeLaMare%20rearrangement
|
The Kornblum–DeLaMare rearrangement is a rearrangement reaction in organic chemistry in which a primary or secondary organic peroxide is converted to the corresponding ketone and alcohol under acid or base catalysis. The reaction is relevant as a tool in organic synthesis and is a key step in the biosynthesis of prostaglandins.
The base can be a hydroxide such as potassium hydroxide or an amine such as triethylamine.
Reaction mechanism
In the reaction mechanism for this organic reaction the base abstracts the acidic α-proton of the peroxide 1 to form the carbanion 4 as a reactive intermediate which rearranges to the ketone 2 with expulsion of the hydroxyl anion 3'. This intermediate gains a proton forming the alcohol 3.
Deprotonation and rearrangement can also be a concerted reaction without formation of 4.
An alternative reaction mechanism involving direct nucleophilic displacement on the peroxide link of the amine followed by an elimination reaction is considered unlikely based on the outcome of this model reaction:
The peroxide 1 converts to the hydroxyketone 2 by action of triethylamine but the alternative route through hydroxylamine 3 by nucleophilic displacement with Lithium diisopropylamide and the ammonium salt 4 (by methylation with methyl trifluoromethanesulfonate) fails.
The reaction, formally a rearrangement, ranks under the elimination reactions as already observed by the original authors. Not only alkoxides but any leaving group capable of carrying a nega
|
https://en.wikipedia.org/wiki/William%20Leighton%20Carss
|
William Leighton Carss (February 15, 1865 – May 31, 1931) was a U.S. Representative from Minnesota; born in Pella, Marion County, Iowa and subsequently moved with his parents to Des Moines, Iowa, in 1867. There he attended the public schools, studied civil and mechanical engineering and followed that profession for a number of years. He moved to St. Louis County, Minnesota in 1893 and settled in Proctor where he found work as a locomotive engineer and became a member of the Brotherhood of Locomotive Engineers. Carss was elected as a Farmer-Labor candidate to the 66th congress (March 4, 1919 – March 3, 1921) from Minnesota's 8th congressional district.
Carss was fond of British literature, reciting selections from Shakespeare, Carlyle and Burns by heart. He sponsored pro-labor legislation during his first term, supporting old age pensions (anticipating the Social Security system), women's rights and (to the dismay of some of his supporters) the Prohibition Amendment.
Carss was an unsuccessful candidate for reelection as a Democrat in 1920 to the 67th congress and for election in 1922 to the 68th congress. He was elected on the Farmer-Labor ticket to the 69th and 70th congresses (March 4, 1925 – March 3, 1929); but was defeated for reelection in 1928 to the 71st congress. Carss moved to Duluth in 1929 where he resumed his position as a locomotive engineer at Proctor. He was unsuccessful in his 1930 bid for election to the 72nd congress. He died in Duluth on May 31, 1931, a
|
https://en.wikipedia.org/wiki/Firing%20squad%20synchronization%20problem
|
The firing squad synchronization problem is a problem in computer science and cellular automata in which the goal is to design a cellular automaton that, starting with a single active cell, eventually reaches a state in which all cells are simultaneously active. It was first proposed by John Myhill in 1957 and published (with a solution by John McCarthy and Marvin Minsky) in 1962 by Edward F. Moore.
Problem statement
The name of the problem comes from an analogy with real-world firing squads: the goal is to design a system of rules according to which an officer can command an execution detail to fire so that its members fire their rifles simultaneously.
More formally, the problem concerns cellular automata, arrays of finite state machines called "cells" arranged in a line, such that at each time step each machine transitions to a new state as a function of its previous state and the states of its two neighbors in the line. For the firing squad problem, the line consists of a finite number of cells, and the rule according to which each machine transitions to the next state should be the same for all of the cells interior to the line, but the transition functions of the two endpoints of the line are allowed to differ, as these two cells are each missing a neighbor on one of their two sides.
The states of each cell include three distinct states: "active", "quiescent", and "firing", and the transition function must be such that a cell that is quiescent and whose neighbors are
|
https://en.wikipedia.org/wiki/Oliver%20Penrose
|
Oliver Penrose (born 6 June 1929) is a British theoretical physicist.
He is the son of the scientist Lionel Penrose and brother of the mathematical physicist Roger Penrose, chess Grandmaster Jonathan Penrose, and geneticist Shirley Hodgson. He was associated with the Open University for seventeen years and was a Professor of Mathematics at Heriot-Watt University in Edinburgh from 1986 until his retirement in 1994. He has the title of Professor Emeritus at Heriot-Watt, and remains active in research there. His topics of interest include statistical mechanics, phase transitions in metals and the physical chemistry of surfactants. His concept of off-diagonal long-range order is important to the present understanding of superfluids and superconductors. Other more abstract topics in which he has worked include understanding the physical basis for the direction of time and interpretations of quantum mechanics.
References
External links
Penrose's games at Chessgames.com
English physicists
People from Colchester
Academics of the Open University
Academics of Heriot-Watt University
1929 births
Living people
Scientists from Marylebone
Fellows of the Royal Society
Fellows of the Royal Society of Edinburgh
English people of Russian-Jewish descent
English physical chemists
Theoretical physicists
|
https://en.wikipedia.org/wiki/Sukumar%20Nandi
|
Professor Sukumar Nandi is senior member of IEEE and is in Department of Computer Science and Engineering at the Indian Institute of Technology Guwahati. He did his Ph.D. from IIT Kharagpur under Professor P. Pal Chaudhri. He joined IIT Guwahati, and has been teaching there since 1995. He is also a member of the Board of Governors of IIT Guwahati.
He was appointed the "Dean of Academic Affairs" in IIT Guwahati in 2008, and held the post until 2012. He is now the Deputy Director of IIT Guwahati.
References
External links
Sukumar Nandi's Homepage
Publications
Nandi,Sukumar
Indian computer scientists
Senior Members of the IEEE
Year of birth missing (living people)
IIT Kharagpur alumni
Academic staff of the Indian Institute of Technology Guwahati
|
https://en.wikipedia.org/wiki/Symposium%20on%20Principles%20of%20Programming%20Languages
|
The annual ACM SIGPLAN-SIGACT Symposium on Principles of Programming Languages (POPL) is an academic conference in the field of computer science, with focus on fundamental principles in the design, definition, analysis, and implementation of programming languages, programming systems, and programming interfaces. The venue is jointly sponsored by two Special Interest Groups of the Association for Computing Machinery: SIGPLAN and SIGACT.
POPL ranks as A* (top 4%) in the CORE conference ranking.
The proceedings of the conference are hosted at the ACM Digital Library. They were initially under a paywall, but since 2017 they are published in open access as part of the journal Proceedings of the ACM on Programming Languages (PACMPL).
Affiliated events
Declarative Aspects of Multicore Programming (DAMP)
Foundations and Developments of Object-Oriented Languages (FOOL/WOOD)
Partial Evaluation and Semantics-Based Program Manipulation (PEPM)
Practical Applications of Declarative Languages (PADL)
Programming Language Technologies for XML (PLAN-X)
Types in Language Design and Implementation (TLDI)
Verification, Model Checking and Abstract Interpretation (VMCAI)
Languages for Inference (LAFI)
See also
International Conference on Functional Programming (ICFP)
Programming Language Design and Implementation (PLDI)
POPLmark challenge
References
External links
Acceptance Rates of Compiler Conferences
Association for Computing Machinery conferences
Programming langu
|
https://en.wikipedia.org/wiki/Principle%20of%20covariance
|
In physics, the principle of covariance emphasizes the formulation of physical laws using only those physical quantities the measurements of which the observers in different frames of reference could unambiguously correlate.
Mathematically, the physical quantities must transform covariantly, that is, under a certain representation of the group of coordinate transformations between admissible frames of reference of the physical theory. This group is referred to as the covariance group.
The principle of covariance does not require invariance of the physical laws under the group of admissible transformations although in most cases the equations are actually invariant. However, in the theory of weak interactions, the equations are not invariant under reflections (but are, of course, still covariant).
Covariance in Newtonian mechanics
In Newtonian mechanics the admissible frames of reference are inertial frames with relative velocities much smaller than the speed of light. Time is then absolute and the transformations between admissible frames of references are Galilean transformations which (together with rotations, translations, and reflections) form the Galilean group. The covariant physical quantities are Euclidean scalars, vectors, and tensors. An example of a covariant equation is Newton's second law,
where the covariant quantities are the mass of a moving body (scalar), the velocity of the body (vector), the force acting on the body, and the invariant time .
Covari
|
https://en.wikipedia.org/wiki/Semisimple%20operator
|
In mathematics, a linear operator T : V → V on a vector space V is semisimple if every T-invariant subspace has a complementary T-invariant subspace. If T is a semisimple linear operator on V, then V is a semisimple representation of T. Equivalently, a linear operator is semisimple if its minimal polynomial is a product of distinct irreducible polynomials.
A linear operator on a finite dimensional vector space over an algebraically closed field is semisimple if and only if it is diagonalizable.
Over a perfect field, the Jordan–Chevalley decomposition expresses an endomorphism as a sum of a semisimple endomorphism s and a nilpotent endomorphism n such that both s and n are polynomials in x.
See also
Jordan–Chevalley decomposition
Notes
References
Linear algebra
Invariant subspaces
|
https://en.wikipedia.org/wiki/Real%20algebraic%20geometry
|
In mathematics, real algebraic geometry is the sub-branch of algebraic geometry studying real algebraic sets, i.e. real-number solutions to algebraic equations with real-number coefficients, and mappings between them (in particular real polynomial mappings).
Semialgebraic geometry is the study of semialgebraic sets, i.e. real-number solutions to algebraic inequalities with-real number coefficients, and mappings between them. The most natural mappings between semialgebraic sets are semialgebraic mappings, i.e., mappings whose graphs are semialgebraic sets.
Terminology
Nowadays the words 'semialgebraic geometry' and 'real algebraic geometry' are used as synonyms, because real algebraic sets cannot be studied seriously without the use of semialgebraic sets. For example, a projection of a real algebraic set along a coordinate axis need not be a real algebraic set, but it is always a semialgebraic set: this is the Tarski–Seidenberg theorem. Related fields are o-minimal theory and real analytic geometry.
Examples: Real plane curves are examples of real algebraic sets and polyhedra are examples of semialgebraic sets. Real algebraic functions and Nash functions are examples of semialgebraic mappings. Piecewise polynomial mappings (see the Pierce–Birkhoff conjecture) are also semialgebraic mappings.
Computational real algebraic geometry is concerned with the algorithmic aspects of real algebraic (and semialgebraic) geometry. The main algorithm is cylindrical algebraic decompositi
|
https://en.wikipedia.org/wiki/Andrew%20Fire
|
Andrew Zachary Fire (born April 27, 1959) is an American biologist and professor of pathology and of genetics at the Stanford University School of Medicine. He was awarded the 2006 Nobel Prize in Physiology or Medicine, along with Craig C. Mello, for the discovery of RNA interference (RNAi). This research was conducted at the Carnegie Institution of Washington and published in 1998.
Biography
Andrew-Z-Fire was born in Palo Alto, California and raised in Sunnyvale, California in a Jewish family. He graduated from Fremont High School. He attended the University of California, Berkeley for his undergraduate degree, where he received a B.A. in mathematics in 1978 at the age of 19. He then proceeded to the Massachusetts Institute of Technology, where he received a Ph.D. in biology in 1983 under the mentorship of Nobel laureate geneticist Phillip Sharp.
Fire moved to Cambridge, England, as a Helen Hay Whitney Postdoctoral Fellow. He became a member of the MRC Laboratory of Molecular Biology group headed by Nobel laureate biologist Sydney Brenner.
From 1986 to 2003, Fire was a staff member of the Carnegie Institution of Washington’s Department of Embryology in Baltimore, Maryland. The initial work on double stranded RNA as a trigger of gene silencing was published while Fire and his group were at the Carnegie Labs. Fire became an adjunct professor in the Department of Biology at Johns Hopkins University in 1989 and joined the Stanford faculty in 2003. Throughout his career, Fir
|
https://en.wikipedia.org/wiki/Constant%20amplitude%20zero%20autocorrelation%20waveform
|
In signal processing, a Constant Amplitude Zero AutoCorrelation waveform (CAZAC) is a periodic complex-valued signal with modulus one and out-of-phase periodic (cyclic) autocorrelations equal to zero. CAZAC sequences find application in wireless communication systems, for example in 3GPP Long Term Evolution for synchronization of mobile phones with base stations. Zadoff–Chu sequences are well-known CAZAC sequences with special properties.
Example CAZAC Sequence
For a CAZAC sequence of length where is relatively prime to the th symbol is given by:
Even N
Odd N
Power Spectrum of CAZAC Sequence
The power spectrum of a CAZAC sequence is flat.
If we have a CAZAC sequence the time domain autocorrelation is an impulse
The discrete fourier transform of the autocorrelation is flat
Power spectrum is related to autocorrelation by
As a result the power spectrum is also flat.
References
External links
CAZAC Sequence Generator (Java applet)
Signal processing
|
https://en.wikipedia.org/wiki/Lamellar%20bodies
|
In cell biology, lamellar bodies (otherwise known as lamellar granules, membrane-coating granules (MCGs), keratinosomes or Odland bodies) are secretory organelles found in type II alveolar cells in the lungs, and in keratinocytes in the skin. They are oblong structures, appearing about 300-400 nm in width and 100-150 nm in length in transmission electron microscopy images. Lamellar bodies in the alveoli of the lungs fuse with the cell membrane and release pulmonary surfactant into the extracellular space.
Role in lungs
In alveolar cells the phosphatidylcholines (choline-based phospholipids) that are stored in the lamellar bodies serve as pulmonary surfactant after being released from the cell. In 1964, using transmission electron microscopy, which at that time was a relatively new tool for ultrastructural elucidation, John Balis identified the presence of lamellar bodies in type II alveolar cells, and further noted that upon their exocytotic migration to the alveolar surface, lamellar contents would uniformly unravel and spread along the circumference of the alveolus, thus lowering surface tension and similarly, the required alveolar inflation force.
Role in epidermis
In the upper stratum spinosum and stratum granulosum layers of the epidermis, lamellar bodies are secreted from keratinocytes, resulting in the formation of an impermeable, lipid-containing membrane that serves as a water barrier and is required for correct skin barrier function. These bodies release compo
|
https://en.wikipedia.org/wiki/Mike%20Lawrence%20%28bridge%29
|
Michael Steven Lawrence (born May 28, 1940) is an American bridge player, teacher, theorist, and prolific writer.
Biography
Lawrence was born in San Francisco. He started playing bridge while he was a chemistry student at the University of California; as result of a self-inflicted hand injury, he had to postpone the final exams and started playing bridge as a pastime. Bridge became his major interest and he devoted his subsequent life to it.
In 1968, he was invited by Ira Corn to join the newly formed Dallas Aces team. He formed a partnership with Bobby Goldman, with whom he played a 2/1 game forcing system. They started by winning several North American Bridge Championships and, after a long Italian Blue Team reign, returned the world crown to America by winning the Bermuda Bowls in 1970 and 1971. Lawrence and James Jacoby left the Aces in 1973.
Under Ira Corn's mentorship, Lawrence started teaching bridge and subsequently writing books. He has written more than thirty books. He received numerous book-of-the-year awards starting with his first book, How to Read Your Opponents' Cards. He contributed to the theory of 2/1 game forcing systems, and his "2/1 semi-forcing" approach competes with Max Hardy's "unconditional forcing" approach. Together, they wrote the book Standard Bridge Bidding for the 21st Century in 2000. He also helped develop educational bridge software with Fred Gitelman.
In addition to his world championships with the Aces, Lawrence has won another Bermu
|
https://en.wikipedia.org/wiki/Winifred%20Edgerton%20Merrill
|
Winifred Edgerton (September 24, 1862 – September 6, 1951) was born in Ripon, Wisconsin. She was the first woman to receive a degree from Columbia University and the first American woman to receive a PhD in mathematics. She was awarded a PhD with high honors from Columbia University in 1886, by a unanimous vote of the board of trustees, after being rejected once.
Early life and education
Winifred Haring Edgerton was born in Ripon, Wisconsin on September 24, 1862. She was the only
daughter of Clara and Emmett Edgerton, who apparently were well enough off to build her a small home observatory. She earned her B.A. degree from Wellesley College in 1883, and taught for a time at Sylvanus Reed's School. She continued her interest in astronomy by independently using data from the Harvard observatory to calculate the orbit of the Pons-Brooks comet of 1883. She then appealed to Columbia University for permission to use their telescope. On February 4, 1884 the members of the board of trustees agreed, considering her an "exceptional case" and cautioning her "not to disturb the male students." She was required to work as a laboratory assistant to the director of the observatory.
She studied math and astronomy at Columbia which at the time was an all-male institution. Her teachers included Professor John Krom Rees, Professor J. Howard Van Amringe and Professor William Guy Peck. After her first appeal to receive a degree was rejected by the trustees, she was advised by President Fr
|
https://en.wikipedia.org/wiki/Gordon%20S.%20Brown
|
Gordon Stanley Brown (August 30, 1907 in Australia – August 23, 1996 in Tucson, Arizona) was a professor of electrical engineering at MIT. He originated many of the concepts behind automatic-feedback control systems and the numerical control of machine tools. From 1959 to 1968, he served as the dean of MIT's engineering school. With his former student Donald P. Campbell, he wrote Principles of Servomechanisms in 1948, which is still a standard reference in the field.
Biography
Early life
Brown was born in 1907 in Australia. He graduated from the Workingman's College (now the Royal Melbourne Institute of Technology) at the age of 18 with diplomas in civil, electrical and mechanical engineering.
In 1929, Brown entered MIT as a junior, and graduated with a degree in electrical engineering in 1931. Continuing his studies at the Institute, he earned a master's degree in 1934. Since 1931 Brown assisted Harold Hazen in constructing an electro-optical analog computer based on Norbert Wiener's "Cinema Integraph" concept. In 1933 Brown's servomechanisms were displayed at the Century of Progress World Fair. In 1938 Brown received his Ph.D. for the study and making of the practical "Cinema Integraph", under tutelage of Hazen.
MIT career
In 1938 Vannevar Bush left the MIT for the Carnegie Institute. Hazen became the head of Electrical Engineering Department; Brown joined the MIT faculty in 1939 as an assistant professor of electrical engineering and took over the course in control s
|
https://en.wikipedia.org/wiki/HOSMAT
|
HOSMAT multispecialty Hospital Pvt. Ltd. , the Hospital for Orthopaedics, Sports Medicine, Arthritis & Trauma, is a 350-bed speciality hospital in central Bangalore, India. It also includes Hosmat Joint Replacement Center and HOSMAT Neurosciences. It is currently undergoing expansion to 500 beds, which would make it the largest speciality hospital of its kind in Asia.
Initially known as the 'accident hospital', later it was in the news as a centre for knee transplantation procedures. Now in its second decade, it was expanded in 2005 after the acquisition of an old ITI corporate office next door. Now it is India's largest orthopedic and neuro center.
Procedures carried out at the hospital include:
Medical and surgical treatment of arthritis
Joint replacements of the knee, hip, shoulder and elbow
Fibre-optic arthroscopy of various joints
Treatment of fractures, non-union and malunion of fractures, ligament injuries, reconstructive surgeries, specialized Ilizarov surgery (limb lengthening procedure)
Correction of deformities
Spinal surgeries (disc problems, spondylitis, pinched nerves, spine fractures, deformities, scholiosis and tumours)
Paediatric orthopaedics
Industrial injuries
In addition, the Neurosurgery and Neurology Department provides microsurgery, skull base, spine, trauma work, nerve injuries, surgery for brain and spinal cord tumours, slipped discs, paraplegia, hemiplegia, quadraplegia, migraine, muscular disorder, Parkinson's disease, Alzheimer's dementi
|
https://en.wikipedia.org/wiki/Tokamak%20%C3%A0%20configuration%20variable
|
The tokamak à configuration variable (TCV, literally "variable configuration tokamak") is an experimental tokamak located at the École Polytechnique Fédérale de Lausanne (EPFL) Swiss Plasma Center (SPC) in Lausanne, Switzerland. As the largest experimental facility of the Swiss Plasma Center, the TCV tokamak explores the physics of magnetic confinement fusion. It distinguishes itself from other tokamaks with its specialized plasma shaping capability, which can produce diverse plasma shapes without requiring hardware modifications.
The research carried out on TCV contributes to the physics understanding for ITER and future fusion power plants such as DEMO. It is currently part of EUROfusion's Medium-Sized Tokamak (MST) programme, alongside ASDEX Upgrade, MAST Upgrade and WEST.
The TCV tokamak produced its first plasma in November 1992 with full tokamak operation starting in June 1993.
Characteristics
Plasma shaping
TCV features a highly elongated, rectangular vacuum vessel and 16 independently powered coils which facilitate development of new plasma configurations. A notable example is the discovery of significantly improved confinement with the negative triangularity shape in the late 1990s. Novel divertor configurations such as the snowflake divertor were also realised and explored on TCV.
ECRH-ECCD system
Auxiliary heating is provided by the electron cyclotron resonance heating (ECRH) system. EC power in X-mode supplied by the X2 (second harmonic) and X3 (third harmo
|
https://en.wikipedia.org/wiki/CRS%20Robotics
|
CRS Robotics Corporation (currently operating as Thermo CRS Limited) was a robotics company based out of Burlington, Ontario, Canada. CRS Robotics designed, manufactured, distributed, and serviced human scale articulated robots, and laboratory automation systems. Human scale robots have approximately the same reach, speed, the range of motion, the degree of articulation and lifting capacity as a human being and are designed specifically to perform tasks that are hazardous, highly repetitive or generally unsuited for humans. Laboratory Automation applications are used to speed the effort of drug discovery for pharmaceutical and biotechnology customers.
CRS Robotics was notable in the field of automated lab systems due to their developments in high throughput and ultra-high throughput automated systems. Among other things, these developments included their advanced scheduling software, called POLARA, which was an open and extensible platform for the management and control of complex automated systems. As an example, a "good portion of the work" for "the preliminary map of the human genetic code was performed on CRS Automated Lab Systems".
The company commenced operations in 1982 as an engineering firm providing consulting services to Canadian machine tool manufacturers in the area of machine controls. The company sold its first robot, the M1 small robot system, in 1985. The company shipped its first laboratory automation system in 1997. In 1998, they introduced the F3 Robot,
|
https://en.wikipedia.org/wiki/Betz
|
Betz may refer to:
Betz (surname)
Betz Airport, Michigan
Betz cell, giant pyramidal neuron of primary motor cortex
Betz's law, law of physics applying to fluids
Betz, Oise, commune in France
GE Betz, water treatment company
See also
Betts, surname
Willi Betz, logistics company
|
https://en.wikipedia.org/wiki/Tobin%20J.%20Marks
|
Tobin Jay Marks (born November 25, 1944) is an inorganic chemistry Professor, the Vladimir N. Ipatieff Professor of Catalytic Chemistry, Professor of Material Science and Engineering, Professor of Chemical and Biological Engineering, and Professor of Applied Physics at Northwestern University in Evanston, Illinois. Among the themes of his research are synthetic organo-f-element and early-transition metal organometallic chemistry, polymer chemistry, materials chemistry, homogeneous and heterogeneous catalysis, molecule-based photonic materials, superconductivity, metal-organic chemical vapor deposition, and biological aspects of transition metal chemistry.
Marks received his B.S. from the University of Maryland in 1966 in chemistry, and his Ph.D. from the Massachusetts Institute of Technology in 1971 under the direction of F. A. Cotton. He came to Northwestern University in the fall of 1970.
The Marks Group
Historically the Marks group has been organized into four teams (A-D), reflecting the historical strengths and the needs of emerging technologies:
A-team; Organometallics/Catalysis
B-team: Molecular Photonics
C-team: Transparent Oxides
D-team: Molecular Electronics
Marks is known for his ability to tie his efforts to practical problems. Work in organometallics/catalysis (A-team) has traditionally focused on two main areas: Group IV mediated polymerizations and f-element mediated hydroelementation. His extensive work in polymerization catalysts and determination o
|
https://en.wikipedia.org/wiki/Steven%20V.%20Ley
|
Steven Victor Ley (born 10 December 1945) is Professor of Organic Chemistry in the Department of Chemistry at the University of Cambridge, and is a Fellow of Trinity College, Cambridge. He was President of the Royal Society of Chemistry (2000–2002) and was made a CBE in January 2002, in the process. In 2011, he was included by The Times in the list of the "100 most important people in British science".
Education
Ley was educated at Stamford and Loughborough University of Technology where he was awarded a Bachelor of Science and PhD.
Research
Ley's main research field are the total synthesis of biomolecules. His group has published extensively on this topic, and has completed the synthesis of more than 140 natural target compounds, with notable examples including indanamycin, routiennocin, avermectin B1a, okadaic acid, spongistatin, thapsigargin, epothilone A, antascomicin B, bengazole A and rapamycin. His total synthesis of azadirachtin, completed in 2007, is widely regarded as one of the major landmarks in total synthesis. In the course of this work, he has also made substantial advances in many areas of organic chemistry, including the development of new catalysts, protecting groups and reagents. He is one of the inventors of TPAP, a widely employed oxidising reagent. He has also pioneered the use of immobilised reagents and flow techniques in multi-step organic synthesis. This work now incorporates flow chemistry for multistep organic synthesis applications.
By 2020,
|
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.