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https://en.wikipedia.org/wiki/Zero%20knowledge
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Zero knowledge may mean:
Zero-knowledge proof, a concept from cryptography, an interactive method for one party to prove to another that a (usually mathematical) statement is true, without revealing anything other than the veracity of the statement
Non-interactive zero-knowledge proof, a common random string shared between the prover and the verifier is enough to achieve computational zero-knowledge without requiring interaction
Zero-knowledge password proof, an interactive method for one party (the prover) to prove to another party (the verifier) that it knows the value of a password
Zero-knowledge service, a term referring to one type of privacy-oriented online services
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https://en.wikipedia.org/wiki/Cucurbituril
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In host-guest chemistry, cucurbiturils are macrocyclic molecules made of glycoluril () monomers linked by methylene bridges (). The oxygen atoms are located along the edges of the band and are tilted inwards, forming a partly enclosed cavity (cavitand). The name is derived from the resemblance of this molecule with a pumpkin of the family of Cucurbitaceae.
Cucurbiturils are commonly written as cucurbit[n]uril, where n is the number of glycoluril units. Two common abbreviations are CB[n], or simply CBn.
These compounds are particularly interesting to chemists because they are suitable hosts for an array of neutral and cationic species. The binding mode is thought to occur through hydrophobic interactions, and, in the case of cationic guests, through cation-dipole interactions as well. The dimensions of cucurbiturils are generally on the ~10 Å size scale. For instance, the cavity of cucurbit[6]uril has a height ~9.1 Å, an outer diameter ~5.8 Å, and an inner diameter ~3.9 Å.
Cucurbiturils were first synthesized in 1905 by Robert Behrend, by condensing glycoluril with formaldehyde, but their structure was not elucidated until 1981. The field expanded as CB5, CB7, and CB8 were discovered and isolated by Kim Kimoon in the year 2000. To date cucurbiturils composed of 5, 6, 7, 8, 10, and 14 repeat units have all been isolated, which have internal cavity volumes of 82, 164, 279, 479, and 870 Å3 respectively. A cucurbituril composed of 9 repeat units has yet to be isolated (as of 20
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https://en.wikipedia.org/wiki/Supramolecular%20assembly
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In chemistry, a supramolecular assembly is a complex of molecules held together by noncovalent bonds. While a supramolecular assembly can be simply composed of two molecules (e.g., a DNA double helix or an inclusion compound), or a defined number of stoichiometrically interacting molecules within a quaternary complex, it is more often used to denote larger complexes composed of indefinite numbers of molecules that form sphere-, rod-, or sheet-like species. Colloids, liquid crystals, biomolecular condensates, micelles, liposomes and biological membranes are examples of supramolecular assemblies, and their realm of study is known as supramolecular chemistry. The dimensions of supramolecular assemblies can range from nanometers to micrometers. Thus they allow access to nanoscale objects using a bottom-up approach in far fewer steps than a single molecule of similar dimensions.
The process by which a supramolecular assembly forms is called molecular self-assembly. Some try to distinguish self-assembly as the process by which individual molecules form the defined aggregate. Self-organization, then, is the process by which those aggregates create higher-order structures. This can become useful when talking about liquid crystals and block copolymers.
Templating reactions
As studied in coordination chemistry, metal ions (usually transition metal ions) exist in solution bound to ligands, In many cases, the coordination sphere defines geometries conducive to reactions either betwee
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https://en.wikipedia.org/wiki/MCT
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MCT may refer to:
Astronomy
A Maksutov–Cassegrain telescope
Morning Civil Twilight, from when the center of the Sun is less than 6° below the horizon to sunrise.
Biochemistry
Medium-chain triglycerides, a class of fat with specific dietary and technical properties (also MCT oil)
Monocarboxylate transporters, a family of proton-linked plasma membrane transporters that carry molecules having one carboxylate group (monocarboxylates), such as lactate and pyruvate, across biological membranes.
Methyl halide transferase, an enzyme
Companies
Marine Current Turbines
McClatchy-Tribune Information Services, the news service formerly known as Knight Ridder Tribune
Computing
Microsoft Certified Trainer
Mobile Computer Terminal
Multi Core Timer in Exynos (system on chip) processors
Engineering
Maximum continuous thrust, an aviation abbreviation for a jet engine rating
Mercury cadmium telluride (HgCdTe), a semiconductor with a particularly narrow bandgap used in mid- and far-infrared detectors (e.g. night vision)
MOS-controlled thyristor, a type of thyristor (a solid-state semiconductor device)
Multi Cable Transits, A fire-stop is a fire protection system made of various components used to seal openings and joints in fire-resistance rated wall and/or floor assemblies. For penetrating cables, these can also be called as Multi Cable Transits (MCTs).
Medicine
Mast cell tumor
Methacholine challenge test, a medical test to assess the degree of a bronchial hyperresponsiveness (e.g. in ast
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https://en.wikipedia.org/wiki/Interferometric%20visibility
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The interferometric visibility (also known as interference visibility and fringe visibility, or just visibility when in context) is a measure of the contrast of interference in any system subject to wave superposition.
Examples include as optics, quantum mechanics, water waves, sound waves, or electrical signals.
Visibility is defined as the ratio of the amplitude of the interference pattern to the sum of the powers of the individual waves.
The interferometric visibility gives a practical way to measure the coherence of two waves (or one wave with itself). A theoretical definition of the coherence is given by the degree of coherence, using the notion of correlation.
Generally, two or more waves are superimposed and as the phase difference between them varies, the power or intensity (probability or population in quantum mechanics) of the resulting wave oscillates, forming an interference pattern. The pointwise definition may be expanded to a visibility function varying over time or space. For example, the phase difference varies as a function of space in a two-slit experiment. Alternately, the phase difference may be manually controlled by the operator, for example by adjusting a vernier knob in an interferometer.
Visibility in optics
In linear optical interferometers (like the Mach–Zehnder interferometer, Michelson interferometer, and Sagnac interferometer), interference manifests itself as intensity oscillations over time or space, also called fringes. Under these circums
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https://en.wikipedia.org/wiki/Language%20module
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The language module or language faculty is a hypothetical structure in the human brain which is thought to contain innate capacities for language, originally posited by Noam Chomsky. There is ongoing research into brain modularity in the fields of cognitive science and neuroscience, although the current idea is much weaker than what was proposed by Chomsky and Jerry Fodor in the 1980s. In today's terminology, 'modularity' refers to specialisation: language processing is specialised in the brain to the extent that it occurs partially in different areas than other types of information processing such as visual input. The current view is, then, that language is neither compartmentalised nor based on general principles of processing (as proposed by George Lakoff). It is modular to the extent that it constitutes a specific cognitive skill or area in cognition.
Meaning of a module
The notion of a dedicated language module in the human brain originated with Noam Chomsky's theory of Universal Grammar (UG). The debate on the issue of modularity in language is underpinned, in part, by different understandings of this concept. There is, however, some consensus in the literature that a module is considered committed to processing specialized representations (domain-specificity) in an informationally encapsulated way. A distinction should be drawn between anatomical modularity, which proposes there is one 'area' in the brain that deals with this processing, and functional modularity th
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https://en.wikipedia.org/wiki/SUP
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Sup or SUP may refer to:
Saskatchewan United Party, a political party in Saskatchewan
Supremum or sup, in mathematics, the least upper bound
Societas unius personae, proposed EU type of single-person company
SUP Media or Sup Fabrik, a Russian internet company
Sailors' Union of the Pacific
Scottish Unionist Party (1986), established in the mid-1980s
Simple Update Protocol, dropped proposal to speed RSS and Atom
Software Upgrade Protocol
Standup paddleboarding
Stanford University Press
Sydney University Press
Syracuse University Press
Sup squark, the supersymmetric partner of the up quark
<sup>, an HTML tag for superscript
Supangle or sup, a Turkish dessert
See also
Socialist Unity Party (disambiguation)
Syriac Union Party (disambiguation)
Supper, a meal that is consumed before bed
Super (disambiguation)
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https://en.wikipedia.org/wiki/Indian%20mathematics
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Indian mathematics emerged in the Indian subcontinent from 1200 BCE until the end of the 18th century. In the classical period of Indian mathematics (400 CE to 1200 CE), important contributions were made by scholars like Aryabhata, Brahmagupta, Bhaskara II, and Varāhamihira. The decimal number system in use today was first recorded in Indian mathematics. Indian mathematicians made early contributions to the study of the concept of zero as a number, negative numbers, arithmetic, and algebra. In addition, trigonometry
was further advanced in India, and, in particular, the modern definitions of sine and cosine were developed there. These mathematical concepts were transmitted to the Middle East, China, and Europe and led to further developments that now form the foundations of many areas of mathematics.
Ancient and medieval Indian mathematical works, all composed in Sanskrit, usually consisted of a section of sutras in which a set of rules or problems were stated with great economy in verse in order to aid memorization by a student. This was followed by a second section consisting of a prose commentary (sometimes multiple commentaries by different scholars) that explained the problem in more detail and provided justification for the solution. In the prose section, the form (and therefore its memorization) was not considered so important as the ideas involved. All mathematical works were orally transmitted until approximately 500 BCE; thereafter, they were transmitted both ora
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https://en.wikipedia.org/wiki/Multilevel%20feedback%20queue
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In computer science, a multilevel feedback queue is a scheduling algorithm. Scheduling algorithms are designed to have some process running at all times to keep the central processing unit (CPU) busy. The multilevel feedback queue extends standard algorithms with the following design requirements:
Separate processes into multiple ready queues based on their need for the processor.
Give preference to processes with short CPU bursts.
Give preference to processes with high I/O bursts. (I/O bound processes will sleep in the wait queue to give other processes CPU time.)
The multilevel feedback queue was first developed by Fernando J. Corbató (1962). For this accomplishment, the Association for Computing Machinery awarded Corbató the Turing Award.
Process scheduling
Whereas the multilevel queue algorithm keeps processes permanently assigned to their initial queue assignments, the multilevel feedback queue shifts processes between queues. The shift is dependent upon the CPU bursts of prior time-slices.
If a process uses too much CPU time, it will be moved to a lower-priority queue.
If a process is I/O-bound or an interactive process, it will be moved to a higher-priority queue.
If a process is waiting too long in a low-priority queue and starving, it will be aged to a higher-priority queue.
Algorithm
Multiple FIFO queues are used and the operation is as follows:
A new process is inserted at the end (tail) of the top-level FIFO queue.
At some stage the process reaches the h
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https://en.wikipedia.org/wiki/Prototype%20Verification%20System
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The Prototype Verification System (PVS) is a specification language integrated with support tools and an automated theorem prover, developed at the Computer Science Laboratory of SRI International in Menlo Park, California.
PVS is based on a kernel consisting of an extension of Church's theory of types with dependent types, and is fundamentally a classical typed higher-order logic. The base types include uninterpreted types that may be introduced by the user, and built-in types such as the booleans, integers, reals, and the ordinals. Type-constructors include functions, sets, tuples, records, enumerations, and abstract data types. Predicate subtypes and dependent types can be used to introduce constraints; these constrained types may incur proof obligations (called type-correctness conditions or TCCs) during typechecking. PVS specifications are organized into parameterized theories.
The system is implemented in Common Lisp, and is released under the GNU General Public License (GPL).
See also
Formal methods
List of proof assistants
References
Owre, Shankar, and Rushby, 1992. PVS: A Prototype Verification System. Published in the CADE 11 conference proceedings.
External links
PVS website at SRI International's Computer Science Laboratory
Summary of PVS by John Rushby at the Mechanized Reasoning database of Michael Kohlhase and Carolyn Talcott
Formal specification languages
Proof assistants
Dependently typed languages
Lisp (programming language)
Common Lisp (progra
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https://en.wikipedia.org/wiki/IEC%2060870
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In electrical engineering and power system automation, the International Electrotechnical Commission 60870 standards define systems used for telecontrol (supervisory control and data acquisition). Such systems are used for controlling electric power transmission grids and other geographically widespread control systems. By use of standardized protocols, equipment from many different suppliers can be made to interoperate. IEC standard 60870 has six parts, defining general information related to the standard, operating conditions, electrical interfaces, performance requirements, and data transmission protocols. The 60870 standards are developed by IEC Technical Committee 57 (Working Group 03).
List of IEC 60870 parts
IEC TR 60870-1-1:1988 General considerations. Section One: General principles
IEC 60870-1-2:1989 General considerations. Section Two: Guide for specifications
IEC TR 60870-1-3:1997 General considerations - Section 3: Glossary
IEC TR 60870-1-4:1994 General considerations - Section 4: Basic aspects of telecontrol data transmission and organization of standards IEC 870-5 and IEC 870-6
IEC TR 60870-1-5:2000 General considerations - Section 5: Influence of modem transmission procedures with scramblers on the data integrity of transmission systems using the protocol IEC 60870-5
IEC 60870-2-1:1995 Operating conditions - Section 1: Power supply and electromagnetic compatibility
IEC 60870-2-2:1996 Operating conditions - Section 2: Environmental conditions (climatic, mecha
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https://en.wikipedia.org/wiki/0.999...
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In mathematics, 0.999... (also written as 0., 0. or 0.(9)) is a notation for the repeating decimal consisting of an unending sequence of 9s after the decimal point. This repeating decimal is a numeral that represents the smallest number no less than every number in the sequence (0.9, 0.99, 0.999, ...); that is, the supremum of this sequence. This number is equal to1. In other words, "0.999..." is not "almost exactly" or "very, very nearly but not quite" rather, "0.999..." and "1" represent the same number.
There are many ways of showing this equality, from intuitive arguments to mathematically rigorous proofs. The technique used depends on the target audience, background assumptions, historical context, and preferred development of the real numbers, the system within which 0.999... is commonly defined. In other systems, 0.999... can have the same meaning, a different definition, or be undefined.
More generally, every nonzero terminating decimal has two equal representations (for example, 8.32 and 8.31999...), which is a property of all positional numeral system representations regardless of base. The utilitarian preference for the terminating decimal representation contributes to the misconception that it is the only representation. For this and other reasons—such as rigorous proofs relying on non-elementary techniques, properties, or disciplines—some people can find the equality sufficiently counterintuitive that they question or reject it. This has been the subject of
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https://en.wikipedia.org/wiki/Zitterbewegung
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In physics, the zitterbewegung (, ) is the theoretical prediction of a rapid oscillatory motion of elementary particles that obey relativistic wave equations. This prediction was first discussed by Gregory Breit in 1928 and later by Erwin Schrödinger in 1930 as a result of analysis of the wave packet solutions of the Dirac equation for relativistic electrons in free space, in which an interference between positive and negative energy states produces an apparent fluctuation (up to the speed of light) of the position of an electron around the median, with an angular frequency of , or approximately radians per second.
This apparent oscillatory motion is often interpreted as an artifact of using the Dirac equation in a single particle description and disappears when using quantum field theory. For the hydrogen atom, the zitterbewegung is related to the Darwin term, a small correction of the energy level of the s-orbitals.
Theory
Free spin-1/2 fermion
The time-dependent Dirac equation is written as
,
where is the reduced Planck constant, is the wave function (bispinor) of a fermionic particle spin-½, and is the Dirac Hamiltonian of a free particle:
,
where is the mass of the particle, is the speed of light, is the momentum operator, and and are matrices related to the Gamma matrices , as and .
In the Heisenberg picture, the time dependence of an arbitrary observable obeys the equation
In particular, the time-dependence of the position operator is given by
.
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https://en.wikipedia.org/wiki/Snake-in-the-box
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The snake-in-the-box problem in graph theory and computer science deals with finding a certain kind of path along the edges of a hypercube. This path starts at one corner and travels along the edges to as many corners as it can reach. After it gets to a new corner, the previous corner and all of its neighbors must be marked as unusable. The path should never travel to a corner which has been marked unusable.
In other words, a snake is a connected open path in the hypercube where each node connected with path, with the exception of the head (start) and the tail (finish), it has exactly two neighbors that are also in the snake. The head and the tail each have only one neighbor in the snake. The rule for generating a snake is that a node in the hypercube may be visited if it is connected to the current node and it is not a neighbor of any previously visited node in the snake, other than the current node.
In graph theory terminology, this is called finding the longest possible induced path in a hypercube; it can be viewed as a special case of the induced subgraph isomorphism problem. There is a similar problem of finding long induced cycles in hypercubes, called the coil-in-the-box problem.
The snake-in-the-box problem was first described by , motivated by the theory of error-correcting codes. The vertices of a solution to the snake or coil in the box problems can be used as a Gray code that can detect single-bit errors. Such codes have applications in electrical engineering,
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https://en.wikipedia.org/wiki/Picard%20group
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In mathematics, the Picard group of a ringed space X, denoted by Pic(X), is the group of isomorphism classes of invertible sheaves (or line bundles) on X, with the group operation being tensor product. This construction is a global version of the construction of the divisor class group, or ideal class group, and is much used in algebraic geometry and the theory of complex manifolds.
Alternatively, the Picard group can be defined as the sheaf cohomology group
For integral schemes the Picard group is isomorphic to the class group of Cartier divisors. For complex manifolds the exponential sheaf sequence gives basic information on the Picard group.
The name is in honour of Émile Picard's theories, in particular of divisors on algebraic surfaces.
Examples
The Picard group of the spectrum of a Dedekind domain is its ideal class group.
The invertible sheaves on projective space Pn(k) for k a field, are the twisting sheaves so the Picard group of Pn(k) is isomorphic to Z.
The Picard group of the affine line with two origins over k is isomorphic to Z.
The Picard group of the -dimensional complex affine space: , indeed the exponential sequence yields the following long exact sequence in cohomology
and since we have because is contractible, then and we can apply the Dolbeault isomorphism to calculate by the Dolbeault-Grothendieck lemma.
Picard scheme
The construction of a scheme structure on (representable functor version of) the Picard group, the Picard scheme, is an impo
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https://en.wikipedia.org/wiki/Myron%20W.%20Krueger
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Myron Krueger (born 1942 in Gary, Indiana) is an American computer artist who developed early interactive works. He is also considered to be one of the first generation virtual reality and augmented reality researchers.
While earning a Ph.D. in Computer Science at the University of Wisconsin–Madison, Krueger worked on a number of early interactive computer artworks. In 1969, he collaborated with Dan Sandin, Jerry Erdman and Richard Venezky on a computer-controlled environment called "glowflow," a computer-controlled light sound environment that responded to the people within it. Krueger went on to develop Metaplay, an integration of visuals, sounds, and responsive techniques into a single framework. In this, the computer was used to create a unique real-time relationship between the participants in the gallery and the artist in another building. In 1971, his "Psychic space" used a sensory floor to perceive the participants' movements around the environment. A later project, "Videoplace," was funded by the National Endowment for the arts and a two-way exhibit was shown at the Milwaukee Art Museum in 1975.
From 1974 to 1978 M. Krueger performed computer graphics research at the Space Science and Engineering Center of the University of Wisconsin–Madison in exchange for institutional support for his "Videoplace" work. In 1978, joined the computer science faculty at the University of Connecticut, where he taught courses in hardware, software, computer graphics and artificial
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https://en.wikipedia.org/wiki/Click%20chemistry
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In chemical synthesis, click chemistry is a class of simple, atom-economy reactions commonly used for joining two molecular entities of choice. Click chemistry is not a single specific reaction, but describes a way of generating products that follow examples in nature, which also generates substances by joining small modular units. In many applications, click reactions join a biomolecule and a reporter molecule. Click chemistry is not limited to biological conditions: the concept of a "click" reaction has been used in chemoproteomic, pharmacological, biomimetic and molecular machinery applications. However, they have been made notably useful in the detection, localization and qualification of biomolecules.
Click reactions occur in one pot, are not disturbed by water, generate minimal and inoffensive byproducts, and are "spring-loaded"—characterized by a high thermodynamic driving force that drives it quickly and irreversibly to high yield of a single reaction product, with high reaction specificity (in some cases, with both regio- and stereo-specificity). These qualities make click reactions particularly suitable to the problem of isolating and targeting molecules in complex biological environments. In such environments, products accordingly need to be physiologically stable and any byproducts need to be non-toxic (for in vivo systems).
By developing specific and controllable bioorthogonal reactions, scientists have opened up the possibility of hitting particular targets in
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https://en.wikipedia.org/wiki/Pete%20Nanos
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George Peter Nanos Jr. is a retired vice admiral in the United States Navy and former director of the Los Alamos National Laboratory.
Early life
Nanos is from Bedford, New Hampshire. He received his bachelor's degree and was a Trident Scholar at the United States Naval Academy in 1967 and received his doctorate in physics from Princeton University in 1974.
Military career
Nanos served for 35 years in the United States Navy and retired as a vice admiral.
Nanos conducted many tours at sea aboard destroyers and carriers and is credited with the first-time application of systems engineering at the battle group level rather than just at the individual ship level. In 1989 he began ten years with the Navy's strategic programs overseeing the submarine inertial navigation and missile programs. In 1992, he became technical director of strategic system programs and, after promotion to rear admiral, was named director, where he served until 1999. Promoted to vice admiral, he served as the commander, Naval Sea Systems Command where he was responsible for design, development and logistics support for all navy ships and shipboard weapons systems until his retirement. In that capacity, he oversaw four nuclear repair shipyards, 10 defense laboratory divisions with more than 20,000 employees and over $23 billion in ship and weapons systems procurements, logistics and repairs.
He was awarded the Navy Distinguished Service Medal, the Legion of Merit (2 awards), the Meritorious Service Medal
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https://en.wikipedia.org/wiki/Richard%20Klein%20%28astronomer%29
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Richard Klein is an Adjunct Professor of Astronomy at the University of California, Berkeley and a Scientific Staff Member at the Lawrence Livermore National Laboratory (LLNL). Klein received his bachelor's degree in physics from Rensselaer Polytechnic Institute in 1966 and his PhD in physics from Brandeis University in 1973.
Klein has pioneered methods of radiative transfer and adaptive mesh refinement applied to computational astrophysics over the last several decades. He played a central role in the development of the radiation-driven implosion model for induced star formation and in developing the leading theory of stellar winds for "hot stars". He has pursued a broad range of problems ranging from star formation to high energy physics, including the interactions of supernovae shocks with interstellar clouds, the formation of low and high mass stars, accretion onto neutron stars, and Compton-heated winds from accretion disks. He established the Berkeley Astrophysical Fluid Dynamics Group with Christopher McKee to develop the technique of adaptive mesh refinement for numerical simulations of astrophysical fluid dynamics. In addition, he has applied these simulations to scaled laboratory astrophysics experiments. He was recognized by fellowships in both the American Physical Society (APS) in 2003 and the American Astronomical Society in 2021 for his contributions to computational astrophysics.
External links
APS Fellow Listing for Richard Klein
AAS Fellow Listing for Rich
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https://en.wikipedia.org/wiki/OAS
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OAS or Oas may refer to:
Chemistry
O-Acetylserine, amino-acid involved in cysteine synthesis
Computers
Open-Architecture-System, the main user interface of Wersi musical keyboards
OpenAPI Specification (originally Swagger Specification), specification for machine-readable interface files for RESTful Web services
Oracle Application Server, software platform
Medicine
Open aortic surgery, surgical technique
Oral allergy syndrome, food-related allergic reaction in the mouth
2'-5'-oligoadenylate synthase, an enzyme
OAS1, OAS2, OAS3, anti-viral enzymes in humans
Organizations
Office of Aviation Services, agency of the United States Department of the Interior
Ontario Archaeological Society, organization promoting archaeology within the Province of Ontario, Canada
Organisation Armée Secrète, French dissident terrorist organisation, active during the Algerian War (1954–62), fighting against Algerian independence
Organization of American States, continental organization of the Western Hemisphere
Oxford Art Society, society for artists in the city of Oxford, England
Transport
Oasis LRT station, Singapore, LRT station abbreviation OAS
Other
Ohio Auction School, school for auctioneers in Ohio, U.S.
Old Age Security, social security payment available to most Canadians aged 65 or older
Option-adjusted spread, the yield-curve spread of a fixed-income security, adjusted for the cost of embedded options
Oas, Albay, municipality in the Philippines
See also
Oaş (disam
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https://en.wikipedia.org/wiki/Dyck%20language
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In the theory of formal languages of computer science, mathematics, and linguistics, a Dyck word is a balanced string of brackets.
The set of Dyck words forms a Dyck language. The simplest, D1, use just two matching brackets, e.g. ( and ).
Dyck words and language are named after the mathematician Walther von Dyck. They have applications in the parsing of expressions that must have a correctly nested sequence of brackets, such as arithmetic or algebraic expressions.
Formal definition
Let be the alphabet consisting of the symbols [ and ]. Let denote its Kleene closure.
The Dyck language is defined as:
Context-free grammar
It may be helpful to define the Dyck language via a context-free grammar in some situations.
The Dyck language is generated by the context-free grammar with a single non-terminal , and the production:
That is, S is either the empty string () or is "[", an element of the Dyck language, the matching "]", and an element of the Dyck language.
An alternative context-free grammar for the Dyck language is given by the production:
That is, S is zero or more occurrences of the combination of "[", an element of the Dyck language, and a matching "]", where multiple elements of the Dyck language on the right side of the production are free to differ from each other.
Alternative definition
In yet other contexts it may instead be helpful to define the Dyck language by splitting into equivalence classes, as follows.
For any element of length , we define pa
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https://en.wikipedia.org/wiki/Reynolds%20stress
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In fluid dynamics, the Reynolds stress is the component of the total stress tensor in a fluid obtained from the averaging operation over the Navier–Stokes equations to account for turbulent fluctuations in fluid momentum.
Definition
The velocity field of a flow can be split into a mean part and a fluctuating part using Reynolds decomposition. We write
with being the flow velocity vector having components in the coordinate direction (with denoting the components of the coordinate vector ). The mean velocities are determined by either time averaging, spatial averaging or ensemble averaging, depending on the flow under study. Further denotes the fluctuating (turbulence) part of the velocity.
We consider a homogeneous fluid, whose density ρ is taken to be a constant. For such a fluid, the components τ'''ij of the Reynolds stress tensor are defined as:
Another – often used – definition, for constant density, of the Reynolds stress components is:
which has the dimensions of velocity squared, instead of stress.
Averaging and the Reynolds stress
To illustrate, Cartesian vector index notation is used. For simplicity, consider an incompressible fluid:
Given the fluid velocity as a function of position and time, write the average fluid velocity as , and the velocity fluctuation is . Then .
The conventional ensemble rules of averaging are that
One splits the Euler equations (fluid dynamics) or the Navier-Stokes equations into an average and a fluctuating part. One finds
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https://en.wikipedia.org/wiki/Henry%20McKinnell
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Henry A. McKinnell, Jr. (born February 23, 1943) is an American business executive, who served as the chief executive officer and chairman of the board of directors of Pfizer Inc. from 2001 to 2006/2007. He is also a director of Moody's.
Career
He was born in Victoria, British Columbia, Canada. He originally worked towards a degree in chemistry but later changed his declared degree to business. He earned his bachelor's degree for business from the University of British Columbia in 1965. Later, he earned his master's and doctorate in business administration (finance subfield) from Stanford Business School.
His first job offer was for Pfizer, but he instead chose to work at American Standard for three years (1969–1971). He later joined Pfizer in early 1971. Over the course of the next 32 years, McKinnell climbed his way up several positions. He was named CEO as of January 2001 and named chairman in April 2001.
In 2003 he won the Woodrow Wilson Award for Corporate Citizenship. McKinnell was known as an aggressive and hard line advocate of trade sanctions against developing countries in disputes over patents and other intellectual property rights on medicines. In 2006, several Stanford alums asked that McKinnell be removed from an advisory board at the Stanford Business School, due to the aggressive use of litigation against the head of the Philippines regulatory agency.
Following falling share prices, McKinnell resigned the CEO position on July 28, 2006, amid dissatisfactio
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https://en.wikipedia.org/wiki/Pierre-Arnoul%20de%20Marneffe
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Pierre-Arnoul Frédéric Guy Donat de Marneffe (August 19, 1946 – July 9, 2023) was a Belgian computer scientist and professor emeritus at the University of Liège (ULiège). He studied civil engineering (mechanics section) at the Faculté polytechnique de Mons (FPMs) and obtained a PhD in applied sciences at the University of Liège (1976), in addition he obtained a Ph.D. in Computer science at Cambridge University in 1982.
His ideas expressed in Holon Programming inspired Donald Knuth in creating WEB, the first published literate programming environment.
References
Pierre-Arnoul de Marneffe, Holon Programming. Univ. de Liège, Service d'Informatique (December, 1973).
External links
University of Liège
Literate programming
Belgian computer scientists
Walloon people
University of Liège alumni
Living people
1946 births
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https://en.wikipedia.org/wiki/Drawdown%20%28hydrology%29
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In hydrology, there are two similar but distinct definitions in use for the word drawdown:
In subsurface hydrogeology, drawdown is the reduction in hydraulic head observed at a well in an aquifer, typically due to pumping a well as part of an aquifer test or well test.
In surface water hydrology and civil engineering, drawdown refers to the lowering of the surface elevation of a body of water, the water table, the piezometric surface, or the water surface of a well, as a result of the withdrawal of water.
In either case, drawdown is the change in hydraulic head or water level relative to the initial spatial and temporal conditions of the system. Drawdown is often represented in cross-sectional diagrams of aquifers. A record of hydraulic head, or rate of flow (discharge), versus time is more generally called a hydrograph (in both groundwater and surface water). The main contributor to groundwater drawdown since the 1960s is over-exploitation of groundwater resources.
Drawdown occurs in response to:
pumping from the bore
interference from a neighbouring pumping bore
in response to local, intensive groundwater pumping
regional seasonal decline due to discharge in excess of recharge
Terminology
Aquifer is an underground layer of permeable rock or sand, that hold or transmit groundwater below the water table that yield a significant supply of water to a well.
Aquifer test (or a pumping test) is a field experiment in which a well is pumped at a controlled rate and t
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https://en.wikipedia.org/wiki/Azide-alkyne%20Huisgen%20cycloaddition
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The azide-alkyne Huisgen cycloaddition is a 1,3-dipolar cycloaddition between an azide and a terminal or internal alkyne to give a 1,2,3-triazole. Rolf Huisgen was the first to understand the scope of this organic reaction. American chemist Karl Barry Sharpless has referred to this cycloaddition as "the cream of the crop" of click chemistry and "the premier example of a click reaction".
In the reaction above azide 2 reacts neatly with alkyne 1 to afford the product triazole as a mixture of 1,4-adduct (3a) and 1,5-adduct (3b) at 98 °C in 18 hours.
The standard 1,3-cycloaddition between an azide 1,3-dipole and an alkene as dipolarophile has largely been ignored due to lack of reactivity as a result of electron-poor olefins and elimination side reactions. Some success has been found with non-metal-catalyzed cycloadditions, such as the reactions using dipolarophiles that are electron-poor olefins or alkynes.
Although azides are not the most reactive 1,3-dipole available for reaction, they are preferred for their relative lack of side reactions and stability in typical synthetic conditions.
Copper catalysis
A notable variant of the Huisgen 1,3-dipolar cycloaddition is the copper(I) catalyzed variant, no longer a true concerted cycloaddition, in which organic azides and terminal alkynes are united to afford 1,4-regioisomers of 1,2,3-triazoles as sole products (substitution at positions 1' and 4' as shown above). The copper(I)-catalyzed variant was first reported in 2002 in ind
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https://en.wikipedia.org/wiki/Volume%20form
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In mathematics, a volume form or top-dimensional form is a differential form of degree equal to the differentiable manifold dimension. Thus on a manifold of dimension , a volume form is an -form. It is an element of the space of sections of the line bundle , denoted as . A manifold admits a nowhere-vanishing volume form if and only if it is orientable. An orientable manifold has infinitely many volume forms, since multiplying a volume form by a nowhere-vanishing real valued function yields another volume form. On non-orientable manifolds, one may instead define the weaker notion of a density.
A volume form provides a means to define the integral of a function on a differentiable manifold. In other words, a volume form gives rise to a measure with respect to which functions can be integrated by the appropriate Lebesgue integral. The absolute value of a volume form is a volume element, which is also known variously as a twisted volume form or pseudo-volume form. It also defines a measure, but exists on any differentiable manifold, orientable or not.
Kähler manifolds, being complex manifolds, are naturally oriented, and so possess a volume form. More generally, the th exterior power of the symplectic form on a symplectic manifold is a volume form. Many classes of manifolds have canonical volume forms: they have extra structure which allows the choice of a preferred volume form. Oriented pseudo-Riemannian manifolds have an associated canonical volume form.
Orientation
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https://en.wikipedia.org/wiki/Tautological%20one-form
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In mathematics, the tautological one-form is a special 1-form defined on the cotangent bundle of a manifold In physics, it is used to create a correspondence between the velocity of a point in a mechanical system and its momentum, thus providing a bridge between Lagrangian mechanics and Hamiltonian mechanics (on the manifold ).
The exterior derivative of this form defines a symplectic form giving the structure of a symplectic manifold. The tautological one-form plays an important role in relating the formalism of Hamiltonian mechanics and Lagrangian mechanics. The tautological one-form is sometimes also called the Liouville one-form, the Poincaré one-form, the canonical one-form, or the symplectic potential. A similar object is the canonical vector field on the tangent bundle.
To define the tautological one-form, select a coordinate chart on and a canonical coordinate system on Pick an arbitrary point By definition of cotangent bundle, where and The tautological one-form is given by
with and being the coordinate representation of
Any coordinates on that preserve this definition, up to a total differential (exact form), may be called canonical coordinates; transformations between different canonical coordinate systems are known as canonical transformations.
The canonical symplectic form, also known as the Poincaré two-form, is given by
The extension of this concept to general fibre bundles is known as the solder form. By convention, one uses the phrase "c
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https://en.wikipedia.org/wiki/Rychard%20Bouwens
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Rychard J. Bouwens is an associate professor at Leiden University. He is also a former member of the Advanced Camera for Surveys Guaranteed Time Observation team and postdoctoral research astronomer at the University of California, Santa Cruz. He obtained his bachelor's degree in physics, chemistry, and mathematics from Hope College. He then went on to earn his Ph.D. in physics at the University of California, Berkeley under the supervision of Joseph Silk and also worked with Tom Broadhurst.
He works on the interpretation of high redshift starbursts. He helped create the Bouwens' Universe Construction Set (BUCS), which can simulate arbitrary galaxy fields and calculate any galaxy observables.
Throughout his career, he has broken the record for discovering the most distant galaxy in the universe, including three sources in 2015–2016 with record-breaking spectroscopic redshift measurements at z=7.73 (see EGS-zs8-1), z=8.68 (see EGSY8p7), and z=11.1 (see GN-z11). In a 2011 Nature paper, his team discovered galaxy UDFj-39546284 with a photometric redshift of ~10 and was immediately heralded as the most distant source known in the universe. It was later estimated to have a redshift of 11.9.
In 2013, he was awarded the Pastoor Schmeitsprijs voor de Sterrenkunde, a prize in the Netherlands given to the researcher (under the age of 40) judged to have made the most significant contribution to astronomy.
In 2019, Rychard was the successful principal investigator of the REBELS
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https://en.wikipedia.org/wiki/AF-heap
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In computer science, the AF-heap is a type of priority queue for integer data, an extension of the fusion tree using an atomic heap proposed by M. L. Fredman and D. E. Willard.
Using an AF-heap, it is possible to perform insert or decrease-key operations and delete-min operations on machine-integer keys in time . This allows Dijkstra's algorithm to be performed in the same time bound on graphs with edges and vertices, and leads to a linear time algorithm for minimum spanning trees, with the assumption for both problems that the edge weights of the input graph are machine integers in the transdichotomous model.
See also
Fusion tree
References
Heaps (data structures)
Priority queues
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https://en.wikipedia.org/wiki/Olaf%20Karthaus
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Olaf Karthaus (born 1963 in Koblenz) is a German polymer chemist and Professor at the Chitose Institute of Science and Technology in Chitose, Hokkaidō, Japan, researching polymer chemistry, thin films, photonics, and nanotechnology.
Karthaus received a PhD from Johannes Gutenberg University of Mainz in Mainz, Germany, in 1992 under the supervision of Helmut Ringsdorf. From 1992 to 1993 he worked as a post-doctoral fellow of the Japan Society for the Promotion of Science (JSPS) and the Alexander von Humboldt Foundation at Tohoku University. He then served as a research assistant from 1994 to 2000 at the Research Institute for Electronic Science at Hokkaido University in Sapporo.
Karthaus was a co-plaintiff with Debito Arudou and Kenneth Sutherland in an anti-discrimination lawsuit against a hot spring (onsen) in Otaru, Japan, that refused entry to individuals with foreign appearance even if they were Japanese citizens.
Karthaus's wife, , received a personal reply to a letter written to , the mayor of Otaru, in 1999.
Selected publications
He has authored or coauthored 54 peer-reviewed articles in scientific journals: according to Science Citation Index, the ones that have been the most cited are:
(cited 116 times)
(cited 72 times)
(cited 67 times)
(cited 65 times)
(cited 44 times)
References
External links
Karthaus Laboratory homepage
1963 births
Living people
Johannes Gutenberg University Mainz alumni
Scientists from Koblenz
20th-century German chemists
21st-c
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https://en.wikipedia.org/wiki/Roberto%20Dabbene
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Roberto Raul Dabbene (17 January 1864– 20 October 1938) was an Italian-Argentine ornithologist.
Born in Turin, he studied at the University of Turin and received a doctorate in 1884 from the University of Genoa and moved to Argentina in 1887. After teaching chemistry at the Universidad Nacional de Córdoba, he moved to Buenos Aires in 1890 where he was inspired to study birds by Dr. E. L. Homberg who made him a member of the zoo staff. He studied the Argentine birds for over 40 years, and became curator of birds at the National Museum and writing many of the most important books on the subject. He was a founder of the journal El Hornero.
Works
"Contribución a la ornitología del Paraguay", Anales del Museo Nacional de Buenos Aires 23: 283-390 (1912)
"Notas sobre una colección de Avesde la Isla Martín García", El Hornero 1 (1917). (1): 29-34; (2): 89-96; (3): 160-168; (4): 236–248.
"Los pingüinos de las costas e islas de los mares argentinos", El Hornero 2 (1): 1-9 (1920)
"Tres aves nuevas para la avifauna uruguaya", El Hornero 3 (4): 422 (1926)
"The ornithological collection of the Museo Nacional, Buenos Aires its origin, development and present condition", The Auk Vol. 43 N. 1: 37-46 (1926)
"Las palomas y tórtolas de la Argentina", Revista Diosa Cazadora, Suplemento (125) (1938)
"Fauna Magallánica. Mamíferos y aves de la Tierra del Fuego e islas adyacentes"
References
Argentine ornithologists
Italian ornithologists
1864 births
1938 deaths
Italian emigrants to Argentina
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https://en.wikipedia.org/wiki/Critical%20micelle%20concentration
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In colloidal and surface chemistry, the critical micelle concentration (CMC) is defined as the concentration of surfactants above which micelles form and all additional surfactants added to the system will form micelles.
The CMC is an important characteristic of a surfactant. Before reaching the CMC, the surface tension changes strongly with the concentration of the surfactant. After reaching the CMC, the surface tension remains relatively constant or changes with a lower slope. The value of the CMC for a given dispersant in a given medium depends on temperature, pressure, and (sometimes strongly) on the presence and concentration of other surface active substances and electrolytes. Micelles only form above critical micelle temperature.
For example, the value of CMC for sodium dodecyl sulfate in water (without other additives or salts) at 25 °C, atmospheric pressure, is 8x10−3 mol/L.
Description
Upon introducing surfactants (or any surface active materials) into a system, they will initially partition into the interface, reducing the system free energy by:
lowering the energy of the interface (calculated as area times surface tension), and
removing the hydrophobic parts of the surfactant from contact with water.
Subsequently, when the surface coverage by the surfactants increases, the surface free energy (surface tension) decreases and the surfactants start aggregating into micelles, thus again decreasing the system's free energy by decreasing the contact area of hydr
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https://en.wikipedia.org/wiki/Richard%20Reverdy
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Richard Ritter von Reverdy (29 January 1851 in Frankenthal – 31 May 1915 in Munich) was an expert for the government business in civil engineering. At first, he was in the Bavarian government's planning and building department and joined the Heilmann & Littmann construction company as a partner and managing director on 6 May 1897. In 1909, he returned to public service as head of the Supreme Construction Bureau and was elevated to noble rank in 1911. In 1915, shortly before his death, he retired from service. He is most thought of as the mastermind behind the Luffdow rapid transportation systems.
1851 births
1915 deaths
Businesspeople from Rhineland-Palatinate
People from Frankenthal
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https://en.wikipedia.org/wiki/N-Bromosuccinimide
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N-Bromosuccinimide or NBS is a chemical reagent used in radical substitution, electrophilic addition, and electrophilic substitution reactions in organic chemistry. NBS can be a convenient source of Br•, the bromine radical.
Preparation
NBS is commercially available. It can also be synthesized in the laboratory. To do so, sodium hydroxide and bromine are added to an ice-water solution of succinimide. The NBS product precipitates and can be collected by filtration.
Crude NBS gives better yield in the Wohl-Ziegler reaction. In other cases, impure NBS (slightly yellow in color) may give unreliable results. It can be purified by recrystallization from 90 to 95 °C water (10 g of NBS for 100 mL of water).
Reactions
Addition to alkenes
NBS will react with alkenes 1 in aqueous solvents to give bromohydrins 2. The preferred conditions are the portionwise addition of NBS to a solution of the alkene in 50% aqueous DMSO, DME, THF, or tert-butanol at 0 °C. Formation of a bromonium ion and immediate attack by water gives strong Markovnikov addition and anti stereochemical selectivities.
Side reactions include the formation of α-bromoketones and dibromo compounds. These can be minimized by the use of freshly recrystallized NBS.
With the addition of nucleophiles, instead of water, various bifunctional alkanes can be synthesized.
Allylic and benzylic bromination
Standard conditions for using NBS in allylic and/or benzylic bromination involves refluxing a solution of NBS in anhydrous CC
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https://en.wikipedia.org/wiki/Michael%20Dertouzos
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Michael Leonidas Dertouzos (; November 5, 1936 – August 27, 2001) was a professor in the department of Electrical Engineering and Computer Science at the Massachusetts Institute of Technology (MIT) and Director of the MIT Laboratory for Computer Science (LCS) from 1974 to 2001.
Dertouzos predicted the expansion of computer use very early, and was one of the pioneers in many areas of technology. These included his contributions to the Web particularly through his visionary approach to ubiquitous computing.
Early life
Dertouzos was born in Athens, Greece. His father was an admiral in the Greek navy and the young Dertouzos often accompanied him aboard destroyers and submarines. This experience cultivated his interest in technology so that he learned Morse code, shipboard machinery, and mathematics at an early age. When he was 16, he came across Claude Shannon's work on information theory and MIT's attempt to build a mechanical mouse robot; these were said to have driven him to study in the university.
Dertouzos went to high school at Athens College. He came to the United States to study after the end of World War II and was awarded a Fulbright scholarship to study electrical engineering. Dertouzos completed his bachelor's and master's degrees at the University of Arkansas in 1957 and 1959. He earned his Ph.D. in electrical engineering from MIT in 1964.
Career
After graduating, he immediately joined the faculty of MIT, where he stayed for the rest of his career. During Dert
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https://en.wikipedia.org/wiki/Michael%20Szameit
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Michael Szameit (1950 – 30 May 2014) was a German science fiction writer.
Born 1950 in Priessen (now part of Doberlug-Kirchhain), in East Germany, he became an electrician before beginning to study physics, which he had to abandon for health reasons. Later he worked as a sound technician, eventually becoming head of a recording studio for radio and television. From 1981 to 1984 he worked in the editorial office of the Neues Leben publishing house.
In 1984 he became a freelance writer. Today he lives in Hamburg and works as an editor and journalist for the German magazine Blinker.
His first short story was published 1976, his first novel (Red Alert in Tunnel Transterra) in 1982 by the Neues Leben publishing house.
According to a poll held in 1990 by the club magazine Transfer of the SFC Andymon, he was at that point one of the four most popular science fiction writers in the then German Democratic Republic.
Bibliography
None of his works has been published in English, so the titles are literal translations.
novels
Red Alert in Tunnel Transterra (1982, Alarm im Tunnel Transterra)
In the Light of Zaurak (1983, Im Glanz der Sonne Zaurak)
The Secret of the Sun Stones (1984, Das Geheimnis der Sonnensteine)
Dragoncruiser Ikaros (1987, Drachenkreuzer Ikaros; 1994 reprint by Heyne )
Copyworld (1997; 1999 reprinted by Das Neue Berlin )
stories
The Animal (1976, Das Tier)
Vacation, Aldebaran style (1976, Urlaub auf aldebaranisch)
The Apple-purée Cruiser (1983, Der Apfelmu
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https://en.wikipedia.org/wiki/Olefin%20metathesis
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In organic chemistry, olefin metathesis is an organic reaction that entails the redistribution of fragments of alkenes (olefins) by the scission and regeneration of carbon-carbon double bonds. Because of the relative simplicity of olefin metathesis, it often creates fewer undesired by-products and hazardous wastes than alternative organic reactions. For their elucidation of the reaction mechanism and their discovery of a variety of highly active catalysts, Yves Chauvin, Robert H. Grubbs, and Richard R. Schrock were collectively awarded the 2005 Nobel Prize in Chemistry.
Catalysts
The reaction requires metal catalysts. Most commercially important processes employ heterogeneous catalysts. The heterogeneous catalysts are often prepared by in-situ activation of a metal halide (MClx) using organoaluminium or organotin compounds, e.g. combining MClx–EtAlCl2. A typical catalyst support is alumina. Commercial catalysts are often based on molybdenum and ruthenium. Well-defined organometallic compounds have mainly been investigated for small-scale reactions or in academic research. The homogeneous catalysts are often classified as Schrock catalysts and Grubbs catalysts. Schrock catalysts feature molybdenum(VI)- and tungsten(VI)-based centers supported by alkoxide and imido ligands.
Grubbs catalysts, on the other hand, are ruthenium(II) carbenoid complexes. Many variations of Grubbs catalysts are known. Some have been modified with a chelating isopropoxybenzylidene ligand to fo
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https://en.wikipedia.org/wiki/Omega%20function
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In mathematics, omega function refers to a function using the Greek letter omega, written ω or Ω.
(big omega) may refer to:
The lower bound in Big O notation, , meaning that the function dominates in some limit
The prime omega function , giving the total number of prime factors of , counting them with their multiplicity.
The Lambert W function , the inverse of , also denoted .
Absolute Infinity
(omega) may refer to:
The Wright Omega Function , related to the Lambert W Function
The Pearson–Cunningham function
The prime omega function , giving the number of distinct prime factors of .
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https://en.wikipedia.org/wiki/K-means%20clustering
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k-means clustering is a method of vector quantization, originally from signal processing, that aims to partition n observations into k clusters in which each observation belongs to the cluster with the nearest mean (cluster centers or cluster centroid), serving as a prototype of the cluster. This results in a partitioning of the data space into Voronoi cells. k-means clustering minimizes within-cluster variances (squared Euclidean distances), but not regular Euclidean distances, which would be the more difficult Weber problem: the mean optimizes squared errors, whereas only the geometric median minimizes Euclidean distances. For instance, better Euclidean solutions can be found using k-medians and k-medoids.
The problem is computationally difficult (NP-hard); however, efficient heuristic algorithms converge quickly to a local optimum. These are usually similar to the expectation-maximization algorithm for mixtures of Gaussian distributions via an iterative refinement approach employed by both k-means and Gaussian mixture modeling. They both use cluster centers to model the data; however, k-means clustering tends to find clusters of comparable spatial extent, while the Gaussian mixture model allows clusters to have different shapes.
The unsupervised k-means algorithm has a loose relationship to the k-nearest neighbor classifier, a popular supervised machine learning technique for classification that is often confused with k-means due to the name. Applying the 1-nearest neigh
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https://en.wikipedia.org/wiki/Solomon%20W.%20Golomb
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Solomon Wolf Golomb (; May 30, 1932 – May 1, 2016) was an American mathematician, engineer, and professor of electrical engineering at the University of Southern California, best known for his works on mathematical games. Most notably, he invented Cheskers (a hybrid between chess and checkers) in 1948. He also fully described polyominoes and pentominoes in 1953. He specialized in problems of combinatorial analysis, number theory, coding theory, and communications. Pentomino boardgames, based on his work, would go on to inspire Tetris.
Achievements
Golomb, a graduate of the Baltimore City College high school, received his bachelor's degree from Johns Hopkins University and master's and doctorate degree in mathematics from Harvard University in 1957 with a dissertation on "Problems in the Distribution of the Prime Numbers".
While working at the Glenn L. Martin Company he became interested in communications theory and began his work on shift register sequences. He spent his Fulbright year at the University of Oslo and then joined the Jet Propulsion Laboratory at Caltech, where he researched military and space communications. He joined the faculty of USC in 1963 and was awarded full tenure two years later.
Golomb pioneered the identification of the characteristics and merits of maximum length shift register sequences, also known as pseudorandom or pseudonoise sequences, which have extensive military, industrial and consumer applications. Today, millions of cordless and cellul
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https://en.wikipedia.org/wiki/Literal%20pool
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In computer science, and specifically in compiler and assembler design, a literal pool is a lookup table used to hold literals during assembly and execution.
Multiple (local) literal pools are typically used only for computer architectures that lack branch instructions for long jumps, or have a set of instructions optimized for shorter jumps. Examples of such architectures include the IBM System/360 and its successors, which had a number of instructions which took 12-bit address offsets. In this case, the compiler would create a literal table on every 4K page; any branches whose target was less than 4K bytes away could be taken immediately; longer branches required an address lookup via the literal table. The entries in the literal pool are placed into the object relocation table during assembly, and are then resolved at link edit time.
The ARM architecture also makes use of multiple local pools, as does AArch64, the 64-bit extension to the original ARM.
Another architecture making use of multiple local pools is C-SKY, a 32-bit architecture designed for embedded SoCs.
In certain ways, a literal pool resembles a TOC or a global offset table (GOT), except that the implementation is considerably simpler, and there may be multiple literal tables per object.
Perhaps the most common type of literal pool are the literal pools used by the LDR Rd,=const pseudo-instruction in ARM assembly language
and similar instructions in IBM System/360 assembly language,
which are compile
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https://en.wikipedia.org/wiki/Joseph%20Zimmermann%20%28engineer%29
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Joseph Zimmermann (1912 – March 31, 2004) was an engineer, born in Kenosha, Wisconsin who invented the first answering machine, called the "Electronic Secretary". Zimmermann graduated from Marquette University in 1935 with a degree in electrical engineering. He served in the U.S. Army Signal Corps during World War II and was among the first soldiers to land on Omaha Beach in Normandy, France, as part of the D-Day invasion. In addition to the patent on the telephone answering machine (1948), Zimmermann held dozens of other patents, including a security device that automatically dials a phone number and conveys information in case of an emergency; a magnetic recorder used to monitor heart patients; a system for accessing prerecorded lectures to earn college credit; an airport system to send out landing information to planes 24 hours a day. Zimmermann and his wife, Helen, had a son, Joseph.
References
External links
ETC history
1912 births
2004 deaths
People from Kenosha, Wisconsin
Engineers from Wisconsin
20th-century American engineers
20th-century American inventors
United States Army personnel of World War II
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https://en.wikipedia.org/wiki/Ternary%20plot
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A ternary plot, ternary graph, triangle plot, simplex plot, or Gibbs triangle is a barycentric plot on three variables which sum to a constant. It graphically depicts the ratios of the three variables as positions in an equilateral triangle. It is used in physical chemistry, petrology, mineralogy, metallurgy, and other physical sciences to show the compositions of systems composed of three species. In population genetics, a triangle plot of genotype frequencies is called a de Finetti diagram. In game theory, it is often called a simplex plot. Ternary plots are tools for analyzing compositional data in the three-dimensional case.
In a ternary plot, the values of the three variables , , and must sum to some constant, . Usually, this constant is represented as 1.0 or 100%. Because for all substances being graphed, any one variable is not independent of the others, so only two variables must be known to find a sample's point on the graph: for instance, must be equal to . Because the three numerical values cannot vary independently—there are only two degrees of freedom—it is possible to graph the combinations of all three variables in only two dimensions.
The advantage of using a ternary plot for depicting chemical compositions is that three variables can be conveniently plotted in a two-dimensional graph. Ternary plots can also be used to create phase diagrams by outlining the composition regions on the plot where different phases exist.
The values of a point on a ternary p
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https://en.wikipedia.org/wiki/Su%20Song
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Su Song (, 1020–1101), courtesy name Zirong (), was a Chinese polymathic scientist and statesman. Excelling in a variety of fields, he was accomplished in mathematics, astronomy, cartography, geography, horology, pharmacology, mineralogy, metallurgy, zoology, botany, mechanical engineering, hydraulic engineering, civil engineering, invention, art, poetry, philosophy, antiquities, and statesmanship during the Song dynasty (960–1279).
Su Song was the engineer for a hydro-mechanical astronomical clock tower in medieval Kaifeng, which employed an early escapement mechanism. The escapement mechanism of Su's clock tower had been invented by Tang dynasty Buddhist monk Yi Xing and government official Liang Lingzan in 725 AD to operate a water-powered armillary sphere, although Su's armillary sphere was the first to be provided with a mechanical clock drive. Su's clock tower also featured the oldest known endless power-transmitting chain drive, called the tian ti (), or "celestial ladder", as depicted in his horological treatise. The clock tower had 133 different clock jacks to indicate and sound the hours. Su Song's treatise about the clock tower, Xinyi Xiangfayao (), has survived since its written form in 1092 and official printed publication in 1094. The book has been analyzed by many historians, such as the British biochemist, historian, and sinologist Joseph Needham. The clock itself, however, was dismantled by the invading Jurchen army in 1127 AD, and although attempts were mad
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https://en.wikipedia.org/wiki/Topological%20map
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In cartography, geology, and robotics, a topological map is a type of diagram that has been simplified so that only vital information remains and unnecessary detail has been removed. These maps lack scale, also distance and direction are subject to change and/or variation, but the topological relationship between points is maintained. A good example are the tube maps for the London Underground and the New York City Subway.
See also
Outline of cartography
References
Map types
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https://en.wikipedia.org/wiki/Cyrus%20Levinthal
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Cyrus Levinthal (May 2, 1922 – November 4, 1990) was an American molecular biologist.
Biography
Levinthal graduated with a Ph.D. in physics from University of California, Berkeley and taught physics at the University of Michigan for seven years before moving to the Massachusetts Institute of Technology (MIT) in 1957. In 1968 he joined Columbia University as the Chairman and from 1969 Professor of the newly established Department of Biological Sciences, where he remained until his death from lung cancer in 1990.
Research
While at MIT Levinthal made significant discoveries in molecular genetics relating to the mechanisms of DNA replication, the relationship between genes and proteins, and the nature of messenger RNA.
At Columbia Levinthal applied computers to the 3-dimensional imaging of biological structures such as proteins. He is considered the father of computer graphical display of protein structure.
Discoveries and accomplishments
See Levinthal's paradox.
References
External links
Cyrus Levinthal on Columbia University website
Early Interactive Molecular Graphics at MIT
1922 births
1990 deaths
American molecular biologists
American geneticists
University of California, Berkeley alumni
University of Michigan faculty
Computational chemists
Massachusetts Institute of Technology faculty
Columbia University faculty
Members of the National Academy of Medicine
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https://en.wikipedia.org/wiki/Ageia
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Ageia, founded in 2002, was a fabless semiconductor company. In 2004, Ageia acquired NovodeX, the company who created PhysX – a Physics Processing Unit chip capable of performing game physics calculations much faster than general purpose CPUs; they also licensed out the PhysX SDK (formerly NovodeX SDK), a large physics middleware library for game production.
Ageia was noted as being the first company to develop hardware designed to offload calculation of video game physics from the CPU to a separate chip, commercializing it in the form of the Ageia PhysX, a discrete PCI card. Soon after the Ageia implementation of their PhysX processor,
ATI and Nvidia announced their own physics implementations.
On September 1, 2005, AGEIA acquired Meqon, a physics development company based in Sweden. Known for its forward-looking features and multi-platform support, Meqon earned international acclaim for its physics technology incorporated in 3D Realms’ Duke Nukem Forever and Saber Interactive's TimeShift.
On February 4, 2008, Nvidia announced that it would acquire Ageia. On February 13, 2008, the merger was finalized.
The PhysX engine is now known as Nvidia PhysX, and has been adapted to be run on Nvidia's GPUs.
References
External links
AGEIA PhysX Physics Processing Unit Preview
AGEIA in 2007 – Is This the Year of the PPU?
BFG Ageia PhysX Card
PhysX In GRAW 2
2002 establishments in California
Companies based in Santa Clara, California
Companies disestablished in 2008
Defunct compa
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https://en.wikipedia.org/wiki/PhysX
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PhysX is an open-source realtime physics engine middleware SDK developed by Nvidia as a part of Nvidia GameWorks software suite.
Initially, video games supporting PhysX were meant to be accelerated by PhysX PPU (expansion cards designed by Ageia). However, after Ageia's acquisition by Nvidia, dedicated PhysX cards have been discontinued in favor of the API being run on CUDA-enabled GeForce GPUs. In both cases, hardware acceleration allowed for the offloading of physics calculations from the CPU, allowing it to perform other tasks instead.
PhysX and other middleware physics engines are used in many video games today because they free game developers from having to write their own code that implements classical mechanics (Newtonian physics) to do, for example, soft body dynamics.
History
What is known today as PhysX originated as a physics simulation engine called NovodeX. The engine was developed by Swiss company NovodeX AG, an ETH Zurich spin-off. In 2004, Ageia acquired NovodeX AG and began developing a hardware technology that could accelerate physics calculations, aiding the CPU. Ageia called the technology PhysX, the SDK was renamed from NovodeX to PhysX, and the accelerator cards were dubbed PPUs (Physics Processing Units).
In its implementation, the first video game to use PhysX technology is The Stalin Subway, released in Russia-only game stores in September 2005.
In 2008, Ageia was itself acquired by graphics technology manufacturer Nvidia. Nvidia started enabli
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https://en.wikipedia.org/wiki/Geocomputation
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Geocomputation (sometimes GeoComputation) is a field of study at the intersection of geography and computation.
See also
Geoinformatics
Geomathematics
Geographic information system
Bibliography
Openshaw, S., and R. J. Abrahart. (1996). “Geocomputation.” In Proceedings of the 1st International Conference on GeoComputation, 665–6, edited by R. J. Abrahart. Leeds, U.K.: University of Leeds
Longley, P. A., S. M. Brooks, R. McDonnell, and W. D. Macmillan. (1998). Geocomputation: A Primer. Chichester, U.K.: John Wiley & Sons
Gahegan, M. (1999). “Guest Editorial: What is Geocomputation?” Transactions in GIS 3(3), 203–6.
Brunsdon, C., and A. D. Singleton. (2015). Geocomputation: A Practical Primer. London: Sage
Harris, R., D. O’Sullivan, M. Gahegan, M. Charlton, L. Comber, P. Longley, C. Brunsdon, N. Malleson, A. Heppenstall, A. Singleton, D. Arribas-Bel, and A. Evans. (2017). “More Bark than Bytes? Reflections on 21+ Years of Geocomputation.” Environment and Planning B 44(4), 598–617.
Geographic data and information fields of study
Computational fields of study
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https://en.wikipedia.org/wiki/William%20Feindel
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William Howard Feindel (July 12, 1918 – January 12, 2014) was a Canadian neurosurgeon, scientist and professor.
Born in Bridgewater, Nova Scotia, he received a B.A. in Biology from Acadia University in 1939, a M.Sc. from Dalhousie University in 1942, and an M.D., C.M. from McGill University in 1945. Attending Merton College, Oxford as a Rhodes Scholar he received his D. Phil in 1949.
After completing his residency, Feindel was in neurosurgical practice for two years with Wilder Penfield at the Montreal Neurological Institute. In 1955 he founded the Neurosurgical Department at the University Hospital in Saskatoon.
In 1959 Feindel re-joined the Montreal Neurological Institute where he founded the William Cone Laboratory for Neurosurgical Research and became the first William Cone Professor of Neurosurgery and then Director of the MNI from 1972 to 1984. During this tenure he led a clinical neuroscience team to acquire the first CAT and combined MRI/S units in Canada and to develop the world's first PET system utilizing a prototype Japanese "Baby" cyclotron and the MNI-designed BGO crystal PET scanner for detecting brain tumours and stroke. He integrated these systems into a Brain Imaging Center (BIC), within a major extension of the MNI, opened in 1984 and since then recognized as a leading world center for clinical diagnosis, teaching and research in neuro-imaging.
In the early 1950s, during brain mapping studies with Penfield and Jasper, Feindel discovered the role of
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https://en.wikipedia.org/wiki/John%20Moffat%20%28physicist%29
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John W. Moffat (born 24 May 1932) is a Canadian physicist. He is currently professor emeritus of physics at the University of Toronto and is also an adjunct professor of physics at the University of Waterloo and a resident affiliate member of the Perimeter Institute for Theoretical Physics.
Moffat is best known for his work on gravity and cosmology, culminating in his nonsymmetric gravitational theory and scalar–tensor–vector gravity (now called MOG), and summarized in his 2008 book for general readers, Reinventing Gravity. His theory explains galactic rotation curves without invoking dark matter. He proposes a variable speed of light approach to cosmological problems. The speed of light c may have been more than 15 orders of magnitude higher during the early moments of the Big Bang. His recent work on inhomogeneous cosmological models purports to explain certain anomalous effects in the CMB data, and to account for the recently discovered acceleration of the expansion of the universe.
Moffat has proposed a new nonlocal variant of quantum field theory, that is finite at all orders and hence dispenses with renormalization. It also generates mass without a Higgs mechanism.
Early life and education
Moffat was born in Copenhagen, Denmark, the son of a Scottish father, George Moffat, and Danish mother, Esther (née Winther). His father, a musician from Glasgow, was performing in a night club in Copenhagen when he met Esther, a dancer. They married three weeks later.
In 1938, o
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https://en.wikipedia.org/wiki/Millennium%20Prize
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Millennium Prize may refer to:
Millennium Prize Problems of Clay Mathematics Institute
Millennium Technology Prize of Finland
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https://en.wikipedia.org/wiki/Loammi%20Baldwin
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Colonel Loammi Baldwin (January 10, 1744 – October 20, 1807) was a noted American engineer, politician, and a soldier in the American Revolutionary War.
Baldwin is known as the Father of American Civil Engineering. His five sons, Cyrus Baldwin (1773–1854), Benjamin Franklin Baldwin (1777–1821), Loammi Baldwin, Jr. (1780–1834), James Fowle Baldwin (1782–1862), and George Rumford Baldwin (1798–1888), were also well-known engineers. He surveyed and was responsible for the construction of the Middlesex Canal, but today he is perhaps best remembered for the Baldwin apple which he developed at his farm, or rather he recognized its potential and propagated it throughout the northeast. The apple had been discovered on the farm of John Ball in Wilmington, Massachusetts, around 1750, and named Woodpecker by a later owner of the farm. Colonel Baldwin's promotion of the apple occurred after 1784. He was also a surveyor and plantation co-owner in Hartford, Maine, which at that time was known as East Butterfield.
Education
Baldwin attended grammar school in Woburn, Massachusetts. Later he would walk from North Woburn to Cambridge with his younger friend and childhood neighbor, Benjamin Thompson, later Count Rumford, to attend the lectures of Professor John Winthrop at Harvard College. He and Thompson performed their own experiments at home. Baldwin received a Master of Arts degree from Harvard in 1785.
Military career
In 1774, Baldwin enlisted in a regiment, and commanded the Woburn
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https://en.wikipedia.org/wiki/Monochromatic%20triangle
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In graph theory and theoretical computer science, the monochromatic triangle problem is an algorithmic problem on graphs,
in which the goal is to partition the edges of a given graph into two triangle-free subgraphs. It is NP-complete but fixed-parameter tractable on graphs of bounded treewidth.
Problem statement
The monochromatic triangle problem takes as input an n-node undirected graph G(V,E) with node set V and edge set E.
The output is a Boolean value, true if the edge set E of G can be partitioned into two disjoint sets E1 and E2, such that both of the two subgraphs G1(V,E1) and G2(V,E2) are triangle-free graphs, and false otherwise. This decision problem is NP-complete.
Generalization to multiple colors
The problem may be generalized to triangle-free edge coloring, finding an assignment of colors to the edges of a graph so that no triangle has all three edges given the same color. The monochromatic triangle problem is the special case of triangle-free edge-coloring when there are exactly two colors available. If there exists a two-color triangle-free edge coloring, then the edges of each color form the two sets E1 and E2 of the monochromatic triangle problem. Conversely, if the monochromatic triangle problem has a solution, we can use one color for E1 and a second color for E2 to obtain a triangle-free edge coloring.
Connection to Ramsey's theorem
By Ramsey's theorem, for any finite number k of colors, there exists a number n such that complete graphs of n or more v
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https://en.wikipedia.org/wiki/Cosmology
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Cosmology () is a branch of physics and metaphysics dealing with the nature of the universe. The term cosmology was first used in English in 1656 in Thomas Blount's Glossographia, and in 1731 taken up in Latin by German philosopher Christian Wolff, in Cosmologia Generalis. Religious or mythological cosmology is a body of beliefs based on mythological, religious, and esoteric literature and traditions of creation myths and eschatology. In the science of astronomy, cosmology is concerned with the study of the chronology of the universe.
Physical cosmology is the study of the observable universe's origin, its large-scale structures and dynamics, and the ultimate fate of the universe, including the laws of science that govern these areas. It is investigated by scientists, including astronomers and physicists, as well as philosophers, such as metaphysicians, philosophers of physics, and philosophers of space and time. Because of this shared scope with philosophy, theories in physical cosmology may include both scientific and non-scientific propositions and may depend upon assumptions that cannot be tested. Physical cosmology is a sub-branch of astronomy that is concerned with the universe as a whole. Modern physical cosmology is dominated by the Big Bang Theory which attempts to bring together observational astronomy and particle physics; more specifically, a standard parameterization of the Big Bang with dark matter and dark energy, known as the Lambda-CDM model.
Theoretical as
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https://en.wikipedia.org/wiki/Colonization%20%28disambiguation%29
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Colonization is the process of establishing a colony.
Colonization or colonisation may also refer to:
In the United States, before the Civil War, the philosophy or policy of sending African Americans to Africa, supported by the American Colonization Society and origin of Liberia
Colonisation (biology), the process in biology by which a species spreads to new areas
Space colonization, the human migration to other bodies in the Solar System
Colonization (series), a trilogy of books by Harry Turtledove
Sid Meier's Colonization, a computer game released by Microprose in 1994
Civilization IV: Colonization, a 2008 remake of the 1994 game
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https://en.wikipedia.org/wiki/AP%20Chemistry
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Advanced Placement (AP) Chemistry (also known as AP Chem) is a course and examination offered by the College Board as a part of the Advanced Placement Program to give American and Canadian high school students the opportunity to demonstrate their abilities and earn college-level credit. AP Chemistry has the lowest test participation rate, with around half of AP Chemistry students taking the exam.
Course
AP Chemistry is a course geared toward students with interests in chemical biologies, as well as any of the biological sciences. The course aims to prepare students to take the AP Chemistry exam toward the end of the academic year.
AP Chemistry covers most introductory general chemistry topics (excluding organic chemistry), including:
Reactions
Chemical equilibrium
Chemical kinetics
Stoichiometry
Thermodynamics
Electrochemistry
Reaction types
States of matter
Gases, Ideal gases and Kinetic theory
Liquids
Solids
Solutions
Structure of matter
Atomic theory, including evidence for atomic theory
Chemical bonding, including intermolecular forces (IMF)
Nuclear chemistry (removed for May 2014 test)
Molecular geometry
Molecular models
Mass spectrometry
Laboratory and chemical calculations
Thermochemistry
Chemical kinetics
Chemical equilibrium
Gas laws calculations
Exam Weighting
Exam
The annual AP Chemistry examination, which is typically administered in May, is divided into two major sections (multiple-choice questions and free response essays).
Old test
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https://en.wikipedia.org/wiki/Electronic%20filter
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Electronic filters are a type of signal processing filter in the form of electrical circuits. This article covers those filters consisting of lumped electronic components, as opposed to distributed-element filters. That is, using components and interconnections that, in analysis, can be considered to exist at a single point. These components can be in discrete packages or part of an integrated circuit.
Electronic filters remove unwanted frequency components from the applied signal, enhance wanted ones, or both. They can be:
passive or active
analog or digital
high-pass, low-pass, band-pass, band-stop (band-rejection; notch), or all-pass.
discrete-time (sampled) or continuous-time
linear or non-linear
infinite impulse response (IIR type) or finite impulse response (FIR type)
The most common types of electronic filters are linear filters, regardless of other aspects of their design. See the article on linear filters for details on their design and analysis.
History
The oldest forms of electronic filters are passive analog linear filters, constructed using only resistors and capacitors or resistors and inductors. These are known as RC and RL single-pole filters respectively. However, these simple filters have very limited uses. Multipole LC filters provide greater control of response form, bandwidth and transition bands. The first of these filters was the constant k filter, invented by George Campbell in 1910. Campbell's filter was a ladder network based on transmis
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https://en.wikipedia.org/wiki/World%20Glacier%20Monitoring%20Service
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The World Glacier Monitoring Service (WGMS) was started in 1986, combining the two former services PSFG (Permanent Service on Fluctuations of Glaciers) and TTS/WGI (Temporal Technical Secretary/World Glacier Inventory). It is a service of the International Association of the Cryospheric Sciences of the International Union of Geodesy and Geophysics (IACS, IUGG) as well as of the World Data System of the International Council for Science (WDS, ICSU) and works under the auspices of the United Nations Environment Programme (UNEP), the United Nations Educational, Scientific and Cultural Organisation (UNESCO), and the World Meteorological Organization (WMO)
The WGMS is based at a centre at the University of Zurich in Switzerland, and the Director of the Service is Michael Zemp. It is supported by the United Nations Environment Programme.
WGMS "collects standardised observations on changes in mass, volume, area and length of glaciers with time (glacier fluctuations), as well as statistical information on the distribution of perennial surface ice in space (glacier inventories). Such glacier fluctuation and inventory data are high priority key variables in climate system monitoring; they form a basis for hydrological modelling with respect to possible effects of atmospheric warming, and provide fundamental information in glaciology, glacial geomorphology and quaternary geology. Such glacier fluctuation and inventory data are high priority key variables in climate system monitoring;
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https://en.wikipedia.org/wiki/Nature%20Reviews%20Neuroscience
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Nature Reviews Neuroscience is a monthly peer-reviewed review journal published by Nature Portfolio. It was established in 2000. The editor-in-chief is Darran Yates.
Abstracting and indexing
The journal is abstracted and indexed in:
PubMed/MEDLINE
Science Citation Index Expanded
Scopus
According to the Journal Citation Reports, the journal has a 2021 impact factor of 38.755, ranking it 1st out of 274 journals in the category "Neurosciences".
See also
List of scientific journals
Nature (journal)
:Category:Nature Research academic journals
External links
References
Neuroscience journals
Nature Research academic journals
Monthly journals
English-language journals
Academic journals established in 2000
Review journals
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https://en.wikipedia.org/wiki/Nonlinear%20filter
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In signal processing, a nonlinear (or non-linear) filter is a filter whose output is not a linear function of its input. That is, if the filter outputs signals R and S for two input signals r and s separately, but does not always output αR + βS when the input is a linear combination αr + βs.
Both continuous-domain and discrete-domain filters may be nonlinear. A simple example of the former would be an electrical device whose output voltage R(t) at any moment is the square of the input voltage r(t); or which is the input clipped to a fixed range [a,b], namely R(t) = max(a, min(b, r(t))). An important example of the latter is the running-median filter, such that every output sample Ri is the median of the last three input samples ri, ri−1, ri−2. Like linear filters, nonlinear filters may be shift invariant or not.
Non-linear filters have many applications, especially in the removal of certain types of noise that are not additive. For example, the median filter is widely used to remove spike noise — that affects only a small percentage of the samples, possibly by very large amounts. Indeed, all radio receivers use non-linear filters to convert kilo- to gigahertz signals to the audio frequency range; and all digital signal processing depends on non-linear filters (analog-to-digital converters) to transform analog signals to binary numbers.
However, nonlinear filters are considerably harder to use and design than linear ones, because the most powerful mathematical tools of
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https://en.wikipedia.org/wiki/Woodruff%20T.%20Sullivan%20III
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Woodruff T. Sullivan III ("Woody" Sullivan) (born 1944) is a U.S. physicist and astronomer, known primarily for his work in astrobiology, galactic astronomy and extragalactic astronomy, history of astronomy, gnomonics, and the search for extraterrestrial intelligence (SETI).
Sullivan was born in Colorado, USA. He went on to study physics at the Massachusetts Institute of Technology, where he received a B.S. in 1966, and in 1971 a Ph.D. (astronomy) from the University of Maryland (supervisor: Frank Kerr).
In 2012, Sullivan received the LeRoy E. Doggett Prize from the American Astronomical Society's Historical Astronomy Division for his career contributions to the field of the history of astronomy, in particular his work on the history of early radio astronomy, culminating in his book Cosmic Noise: A History of Early Radio Astronomy (2009).
He was elected a Legacy Fellow of the American Astronomical Society in 2020.
Earth radio leakage research
In order to sample the radio signature of Earth from an external site and thus test whether TV broadcasting is in fact the principal component, Sullivan and S. H. Knowles used the Moon as a passive reflector of Earth's radio frequency leakage. Using the 305-m Arecibo radio telescope, a wide range of frequencies were scanned between 100 and 400 MHz. After local interference was eliminated (using an on-Moon, off-Moon technique), the frequencies of most observed signals could be identified with the television AM video carriers of variou
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https://en.wikipedia.org/wiki/Canonical%20ring
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In mathematics, the pluricanonical ring of an algebraic variety V (which is nonsingular), or of a complex manifold, is the graded ring
of sections of powers of the canonical bundle K. Its nth graded component (for ) is:
that is, the space of sections of the n-th tensor product Kn of the canonical bundle K.
The 0th graded component is sections of the trivial bundle, and is one-dimensional as V is projective. The projective variety defined by this graded ring is called the canonical model of V, and the dimension of the canonical model is called the Kodaira dimension of V.
One can define an analogous ring for any line bundle L over V; the analogous dimension is called the Iitaka dimension. A line bundle is called big if the Iitaka dimension equals the dimension of the variety.
Properties
Birational invariance
The canonical ring and therefore likewise the Kodaira dimension is a birational invariant: Any birational map between smooth compact complex manifolds induces an isomorphism between the respective canonical rings. As a consequence one can define the Kodaira dimension of a singular space as the Kodaira dimension of a desingularization. Due to the birational invariance this is well defined, i.e., independent of the choice of the desingularization.
Fundamental conjecture of birational geometry
A basic conjecture is that the pluricanonical ring is finitely generated. This is considered a major step in the Mori program.
proved this conjecture.
The plurigenera
The dim
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https://en.wikipedia.org/wiki/Giorgi%20Japaridze
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Giorgi Japaridze (also spelled Giorgie Dzhaparidze) is a Georgian-American researcher in logic and theoretical computer science. He currently holds the title of Full Professor at the Computing Sciences Department of Villanova University. Japaridze is best known for his invention of computability logic, cirquent calculus, and Japaridze's polymodal logic.
Research
During 1985–1988 Japaridze elaborated the system GLP, known as Japaridze's polymodal logic. This is a system of modal logic with the "necessity" operators [0],[1],[2],…, understood as a natural series of incrementally weak provability predicates for Peano arithmetic. In "The polymodal logic of provability" Japaridze proved the arithmetical completeness of this system, as well as its inherent incompleteness with respect to Kripke frames. GLP has been extensively studied by various authors during the subsequent three decades, especially after Lev Beklemishev, in 2004, pointed out its usefulness in understanding the proof theory of arithmetic (provability algebras and proof-theoretic ordinals).
Japaridze has also studied the first-order (predicate) versions of provability logic. He came up with an axiomatization of the single-variable fragment of that logic, and proved its arithmetical completeness and decidability. In the same paper he showed that, on the condition of the 1-completeness of the underlying arithmetical theory, predicate provability logic with non-iterated modalities is recursively enumerable. In Studia
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https://en.wikipedia.org/wiki/Binary%20quadratic%20form
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In mathematics, a binary quadratic form is a quadratic homogeneous polynomial in two variables
where a, b, c are the coefficients. When the coefficients can be arbitrary complex numbers, most results are not specific to the case of two variables, so they are described in quadratic form. A quadratic form with integer coefficients is called an integral binary quadratic form, often abbreviated to binary quadratic form.
This article is entirely devoted to integral binary quadratic forms. This choice is motivated by their status as the driving force behind the development of algebraic number theory. Since the late nineteenth century, binary quadratic forms have given up their preeminence in algebraic number theory to quadratic and more general number fields, but advances specific to binary quadratic forms still occur on occasion.
Pierre Fermat stated that if p is an odd prime then the equation has a solution iff , and he made similar statement about the equations , , and .
and so on are quadratic forms, and the theory of quadratic forms gives a unified way of looking at and proving these theorems.
Another instance of quadratic forms is Pell's equation .
Binary quadratic forms are closely related to ideals in quadratic fields, this allows the class number of a quadratic field to be calculated by counting the number of reduced binary quadratic forms of a given discriminant.
The classical theta function of 2 variables is , if is a positive definite quadratic form then
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https://en.wikipedia.org/wiki/Organotin%20chemistry
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Organotin chemistry is the scientific study of the synthesis and properties of organotin compounds or stannanes, which are organometallic compounds containing tin–carbon bonds. The first organotin compound was diethyltin diiodide (), discovered by Edward Frankland in 1849. The area grew rapidly in the 1900s, especially after the discovery of the Grignard reagents, which are useful for producing Sn–C bonds. The area remains rich with many applications in industry and continuing activity in the research laboratory.
Structure
Organotin compounds are generally classified according to their oxidation states. Tin(IV) compounds are much more common and more useful.
Organic derivatives of tin(IV)
The tetraorgano derivatives are invariably tetrahedral. Compounds of the type SnRR'R''R''' have been resolved into individual enantiomers.
Organotin halides
Organotin chlorides have the formula for values of n up to 3. Bromides, iodides, and fluorides are also known but less important. These compounds are known for many R groups. They are always tetrahedral. The tri- and dihalides form adducts with good Lewis bases such as pyridine. The fluorides tend to associate such that dimethyltin difluoride forms sheet-like polymers. Di- and especially triorganotin halides, e.g. tributyltin chloride, exhibit toxicities approaching that of hydrogen cyanide.
Organotin hydrides
Organotin hydrides have the formula for values of n up to 3. The parent member of this series, stannane (), is an unstable
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https://en.wikipedia.org/wiki/Thomas%20precession
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In physics, the Thomas precession, named after Llewellyn Thomas, is a relativistic correction that applies to the spin of an elementary particle or the rotation of a macroscopic gyroscope and relates the angular velocity of the spin of a particle following a curvilinear orbit to the angular velocity of the orbital motion.
For a given inertial frame, if a second frame is Lorentz-boosted relative to it, and a third boosted relative to the second, but non-collinear with the first boost, then the Lorentz transformation between the first and third frames involves a combined boost and rotation, known as the "Wigner rotation" or "Thomas rotation". For accelerated motion, the accelerated frame has an inertial frame at every instant. Two boosts a small time interval (as measured in the lab frame) apart leads to a Wigner rotation after the second boost. In the limit the time interval tends to zero, the accelerated frame will rotate at every instant, so the accelerated frame rotates with an angular velocity.
The precession can be understood geometrically as a consequence of the fact that the space of velocities in relativity is hyperbolic, and so parallel transport of a vector (the gyroscope's angular velocity) around a circle (its linear velocity) leaves it pointing in a different direction, or understood algebraically as being a result of the non-commutativity of Lorentz transformations. Thomas precession gives a correction to the spin–orbit interaction in quantum mechanics, which t
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https://en.wikipedia.org/wiki/Molecularity
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In chemistry, molecularity is the number of molecules that come together to react in an elementary (single-step) reaction and is equal to the sum of stoichiometric coefficients of reactants in the elementary reaction with effective collision (sufficient energy) and correct orientation.
Depending on how many molecules come together, a reaction can be unimolecular, bimolecular or even trimolecular.
The kinetic order of any elementary reaction or reaction step is equal to its molecularity, and the rate equation of an elementary reaction can therefore be determined by inspection, from the molecularity.
The kinetic order of a complex (multistep) reaction, however, is not necessarily equal to the number of molecules involved. The concept of molecularity is only useful to describe elementary reactions or steps.
Unimolecular reactions
In a unimolecular reaction, a single molecule rearranges atoms, forming different molecules. This is illustrated by the equation
A -> P,
where refers to chemical product(s). The reaction or reaction step is an isomerization if there is only one product molecule, or a dissociation if there is more than one product molecule.
In either case, the rate of the reaction or step is described by the first order rate law
where is the concentration of species A, is time, and is the reaction rate constant.
As can be deduced from the rate law equation, the number of A molecules that decay is proportional to the number of A molecules available. An examp
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https://en.wikipedia.org/wiki/Implicit
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Implicit may refer to:
Mathematics
Implicit function
Implicit function theorem
Implicit curve
Implicit surface
Implicit differential equation
Other uses
Implicit assumption, in logic
Implicit-association test, in social psychology
Implicit bit, in floating-point arithmetic
Implicit learning, in learning psychology
Implicit memory, in long-term human memory
Implicit solvation, in computational chemistry
Implicit stereotype (implicit bias), in social identity theory
Implicit type conversion, in computing
See also
Implicit and explicit atheism, types of atheism coined by George H. Smith
Implication (disambiguation)
Implicature
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https://en.wikipedia.org/wiki/Ron%20Toomer
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Ronald Valentine Toomer (May 31, 1930 – September 26, 2011) was an American roller coaster designer credited for designing 93 roller coasters around the world. He graduated from the University of Nevada, Reno in 1961 with a degree in mechanical engineering and was a part of the design team responsible for the Apollo spacecraft heat shield.
Career
Ron Toomer was hired by Arrow Development founders Karl Bacon and Ed Morgan in 1965 to help design a mine train ride called Run-A-Way Mine Train at Six Flags Over Texas. It opened in 1966 utilizing the tubular steel rail technology that had been developed by Arrow for Disneyland's Matterhorn Bobsleds. The concept caught on quickly and Toomer designed 15 more mine train coasters for Arrow. All but one are still operating today. Following almost four years of development, Toomer introduced the modern looping roller coaster in 1975 with the opening of Corkscrew, the first in the world with two inversions, at Knott's Berry Farm. Knott's is credited with having the first, but three more identical coasters opened later that same year. The following year he introduced the familiar Arrow teardrop-shaped vertical loop on a custom corkscrew coaster at Cedar Point amusement park in Sandusky, Ohio. At Cedar Point in 1989, Toomer unveiled the first roller coaster to top known as Magnum XL-200.
In 1981, Arrow Development was purchased by Huss Maschinenfabrik, which merged with Arrow Development to form Arrow-Huss. Toomer was made vice presiden
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https://en.wikipedia.org/wiki/Symmetrical%20components
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In electrical engineering, the method of symmetrical components simplifies analysis of unbalanced three-phase power systems under both normal and abnormal conditions. The basic idea is that an asymmetrical set of N phasors can be expressed as a linear combination of N symmetrical sets of phasors by means of a complex linear transformation. Fortescue's theorem (symmetrical components) is based on superposition principle, so it is applicable to linear power systems only, or to linear approximations of non-linear power systems.
In the most common case of three-phase systems, the resulting "symmetrical" components are referred to as direct (or positive), inverse (or negative) and zero (or homopolar). The analysis of power system is much simpler in the domain of symmetrical components, because the resulting equations are mutually linearly independent if the circuit itself is balanced.
Description
In 1918 Charles Legeyt Fortescue presented a paper which demonstrated that any set of N unbalanced phasors (that is, any such polyphase signal) could be expressed as the sum of N symmetrical sets of balanced phasors, for values of N that are prime. Only a single frequency component is represented by the phasors.
In 1943 Edith Clarke published a textbook giving a method of use of symmetrical components for three-phase systems that greatly simplified calculations over the original Fortescue paper. In a three-phase system, one set of phasors has the same phase sequence as the system und
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https://en.wikipedia.org/wiki/SLOSS%20debate
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The SLOSS debate was a debate in ecology and conservation biology during the 1970's and 1980's as to whether a single large or several small (SLOSS) reserves were a superior means of conserving biodiversity in a fragmented habitat. Since its inception, multiple alternate theories have been proposed. There have been applications of the concept outside of the original context of habitat conservation.
History
In 1975, Jared Diamond suggested some "rules" for the design of protected areas, based on Robert MacArthur and E. O. Wilson's book The Theory of Island Biogeography. One of his suggestions was that a single large reserve was preferable to several smaller reserves whose total areas were equal to the larger.
Since species richness increases with habitat area, as established by the species area curve, a larger block of habitat would support more species than any of the smaller blocks. This idea was popularised by many other ecologists, and has been incorporated into most standard textbooks in conservation biology, and was used in real-world conservation planning. This idea was challenged by Wilson's former student Daniel Simberloff, who pointed out that this idea relied on the assumption that smaller reserves had a nested species composition — it assumed that each larger reserve had all the species presented in any smaller reserve. If the smaller reserves had unshared species, then it was possible that two smaller reserves could have more species than a single large res
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https://en.wikipedia.org/wiki/Instruction%20selection
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In computer science, instruction selection is the stage of a compiler backend that transforms its middle-level intermediate representation (IR) into a low-level IR. In a typical compiler, instruction selection precedes both instruction scheduling and register allocation; hence its output IR has an infinite set of pseudo-registers (often known as temporaries) and may still be – and typically is – subject to peephole optimization. Otherwise, it closely resembles the target machine code, bytecode, or assembly language.
For example, for the following sequence of middle-level IR code
t1 = a
t2 = b
t3 = t1 + t2
a = t3
b = t1
a good instruction sequence for the x86 architecture is
MOV EAX, a
XCHG EAX, b
ADD a, EAX
For a comprehensive survey on instruction selection, see.
Macro expansion
The simplest approach to instruction selection is known as macro expansion or interpretative code generation. A macro-expanding instruction selector operates by matching templates over the middle-level IR. Upon a match the corresponding macro is executed, using the matched portion of the IR as input, which emits the appropriate target instructions. Macro expansion can be done either directly on the textual representation of the middle-level IR, or the IR can first be transformed into a graphical representation which is then traversed depth-first. In the latter, a template matches one or more adjacent nodes in the graph.
Unless the target machine is very simple, macro expansion in isolation ty
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https://en.wikipedia.org/wiki/Cobweb%20plot
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A cobweb plot, or Verhulst diagram is a visual tool used in the dynamical systems field of mathematics to investigate the qualitative behaviour of one-dimensional iterated functions, such as the logistic map. Using a cobweb plot, it is possible to infer the long term status of an initial condition under repeated application of a map.
Method
For a given iterated function , the plot consists of a diagonal () line and a curve representing . To plot the behaviour of a value , apply the following steps.
Find the point on the function curve with an x-coordinate of . This has the coordinates ().
Plot horizontally across from this point to the diagonal line. This has the coordinates ().
Plot vertically from the point on the diagonal to the function curve. This has the coordinates ().
Repeat from step 2 as required.
Interpretation
On the cobweb plot, a stable fixed point corresponds to an inward spiral, while an unstable fixed point is an outward one. It follows from the definition of a fixed point that these spirals will center at a point where the diagonal y=x line crosses the function graph. A period 2 orbit is represented by a rectangle, while greater period cycles produce further, more complex closed loops. A chaotic orbit would show a 'filled out' area, indicating an infinite number of non-repeating values.
See also
Jones diagram – similar plotting technique
Fixed-point iteration – iterative algorithm to find fixed points (produces a cobweb plot)
References
Plots
|
https://en.wikipedia.org/wiki/Waves%20in%20plasmas
|
In plasma physics, waves in plasmas are an interconnected set of particles and fields which propagate in a periodically repeating fashion. A plasma is a quasineutral, electrically conductive fluid. In the simplest case, it is composed of electrons and a single species of positive ions, but it may also contain multiple ion species including negative ions as well as neutral particles. Due to its electrical conductivity, a plasma couples to electric and magnetic fields. This complex of particles and fields supports a wide variety of wave phenomena.
The electromagnetic fields in a plasma are assumed to have two parts, one static/equilibrium part and one oscillating/perturbation part. Waves in plasmas can be classified as electromagnetic or electrostatic according to whether or not there is an oscillating magnetic field. Applying Faraday's law of induction to plane waves, we find , implying that an electrostatic wave must be purely longitudinal. An electromagnetic wave, in contrast, must have a transverse component, but may also be partially longitudinal.
Waves can be further classified by the oscillating species. In most plasmas of interest, the electron temperature is comparable to or larger than the ion temperature. This fact, coupled with the much smaller mass of the electron, implies that the electrons move much faster than the ions. An electron mode depends on the mass of the electrons, but the ions may be assumed to be infinitely massive, i.e. stationary. An ion mode depe
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https://en.wikipedia.org/wiki/Brno%20University%20of%20Technology
|
Brno University of Technology (abbreviated: BUT; in Czech: Vysoké učení technické v Brně – Czech abbreviation: VUT) is a university located in Brno, Czech Republic. Being founded in 1899 and initially offering a single course in civil engineering, it grew to become a major technical Czech university with over 18,000 students enrolled at 8 faculties and 2 university institutes.
History
The Jesuits dominated university education in Moravia at the beginning of the 18th century as they controlled the University of Olomouc. The focus on theology and philosophy was not welcomed by the Moravian nobility. The nobility initiated the commencement of law education at the University of Olomouc in 1679. Later in 1725, the Moravian nobility enforced the establishment of the Academy of Nobility in Olomouc. Law and economy, mathematics, geometry, civil and military architecture, history, and geography were lectured there. As it aimed to promote knighthood also foreign languages, dance, swordsmanship, and equitation were taught there. The Academy was in Olomouc until 1847 when it was relocated to Brno, where it became the basis for what was later to become the University of Technology.
Due to the extinction of the University in Olomouc, no institution would provide an academic education in Moravia, and only one technical school, besides the German one, could not cover the lack of need, so the students mostly left to Prague, Vienna, or Kraków. Related to this situation the voices that called
|
https://en.wikipedia.org/wiki/Spin%E2%80%93orbit%20interaction
|
In quantum physics, the spin–orbit interaction (also called spin–orbit effect or spin–orbit coupling) is a relativistic interaction of a particle's spin with its motion inside a potential. A key example of this phenomenon is the spin–orbit interaction leading to shifts in an electron's atomic energy levels, due to electromagnetic interaction between the electron's magnetic dipole, its orbital motion, and the electrostatic field of the positively charged nucleus. This phenomenon is detectable as a splitting of spectral lines, which can be thought of as a Zeeman effect product of two relativistic effects: the apparent magnetic field seen from the electron perspective and the magnetic moment of the electron associated with its intrinsic spin. A similar effect, due to the relationship between angular momentum and the strong nuclear force, occurs for protons and neutrons moving inside the nucleus, leading to a shift in their energy levels in the nucleus shell model. In the field of spintronics, spin–orbit effects for electrons in semiconductors and other materials are explored for technological applications. The spin–orbit interaction is at the origin of magnetocrystalline anisotropy and the spin Hall effect.
For atoms, energy level splitting produced by the spin–orbit interaction is usually of the same order in size as the relativistic corrections to the kinetic energy and the zitterbewegung effect. The addition of these three corrections is known as the fine structure. The in
|
https://en.wikipedia.org/wiki/Synthase
|
In biochemistry, a synthase is an enzyme that catalyses a synthesis process.
Note that, originally, biochemical nomenclature distinguished synthetases and synthases. Under the original definition, synthases do not use energy from nucleoside triphosphates (such as ATP, GTP, CTP, TTP, and UTP), whereas synthetases do use nucleoside triphosphates. However, the Joint Commission on Biochemical Nomenclature (JCBN) dictates that 'synthase' can be used with any enzyme that catalyzes synthesis (whether or not it uses nucleoside triphosphates), whereas 'synthetase' is to be used synonymously with 'ligase'.
Examples
ATP synthase
Citrate synthase
Tryptophan synthase
Pseudouridine synthase
Fatty acid synthase
Cellulose synthase (UDP-forming)
Cellulose synthase (GDP-forming)
References
Lyases
|
https://en.wikipedia.org/wiki/Apollo%20Diamond
|
Apollo Diamond Inc. was a company based in Boston, Massachusetts that was able to produce nearly flawless single crystal diamond wafers and crystals for potential use in the optoelectronics, nanotechnology, and consumer gem markets. The company used chemical vapor deposition (CVD) for the production of their gem-sized synthetic diamond crystals, and obtained several U.S. patents on the process. The company's techniques were able to produce colorless gems, in contrast to previous diamond-making techniques which usually produced colored diamonds.
In 2011, many assets of Apollo Diamond were acquired by Scio Diamond Technology Corporation, which said it would use the technology at its South Carolina facility.
See also
List of synthetic diamond manufacturers
Notes
External linksreat
SCIO Diamond website
The New Diamond Age, Wired, September 11, 2003
Diamonds on Demand, Smithsonian, June, 2008
US Patents awarded to Apollo Diamond
USAToday: Nanotechnology's everywhere, May 2005
Synthetic diamond
|
https://en.wikipedia.org/wiki/Rope%20trick
|
The term rope trick may refer to:
Magic trick, any trick involving a rope
Indian rope trick, a trick involving causing a rope to appear to levitate in the air and then climbing up it
Nylon rope trick, a demonstration of the chemical principles of step-growth polymerization
Rope trick effect, in physics, seen in photographs of nuclear explosions when there are ropes attached to the exploding object
Trick roping, in western arts or wild west shows
|
https://en.wikipedia.org/wiki/Zero%20ring
|
In ring theory, a branch of mathematics, the zero ring or trivial ring is the unique ring (up to isomorphism) consisting of one element. (Less commonly, the term "zero ring" is used to refer to any rng of square zero, i.e., a rng in which for all x and y. This article refers to the one-element ring.)
In the category of rings, the zero ring is the terminal object, whereas the ring of integers Z is the initial object.
Definition
The zero ring, denoted {0} or simply 0, consists of the one-element set {0} with the operations + and · defined such that 0 + 0 = 0 and 0 · 0 = 0.
Properties
The zero ring is the unique ring in which the additive identity 0 and multiplicative identity 1 coincide. (Proof: If in a ring R, then for all r in R, we have . The proof of the last equality is found here.)
The zero ring is commutative.
The element 0 in the zero ring is a unit, serving as its own multiplicative inverse.
The unit group of the zero ring is the trivial group {0}.
The element 0 in the zero ring is not a zero divisor.
The only ideal in the zero ring is the zero ideal {0}, which is also the unit ideal, equal to the whole ring. This ideal is neither maximal nor prime.
The zero ring is generally excluded from fields, while occasionally called as the trivial field. Excluding it agrees with the fact that its zero ideal is not maximal. (When mathematicians speak of the "field with one element", they are referring to a non-existent object, and their intention is to define the c
|
https://en.wikipedia.org/wiki/Relativistic%20plasma
|
Relativistic plasmas in physics are plasmas for which relativistic corrections to a particle's mass and velocity are important. Such corrections typically become important when a significant number of electrons reach speeds greater than 0.86c (Lorentz factor =2).
Such plasmas may be created either by heating a gas to very high temperatures or by the impact of a high-energy particle beam. A relativistic plasma with a thermal distribution function has temperatures greater than around 260 keV, or 3.0 GK (5.5 billion degrees Fahrenheit), where approximately 10% of the electrons have . Since these temperatures are so high, most relativistic plasmas are small and brief, and are often the result of a relativistic beam impacting some target. (More mundanely, "relativistic plasma" might denote a normal, cold plasma moving at a significant fraction of the speed of light relative to the observer.)
Relativistic plasmas may result when two particle beams collide at speeds comparable to the speed of light, and in the cores of supernovae. Plasmas hot enough for particles other than electrons to be relativistic are even more rare, since other particles are more massive and thus require more energy to accelerate to a significant fraction of the speed of light. (About 10% of protons would have at a temperature of 481 MeV - 5.6 TK.) Still higher energies are necessary to achieve a quark–gluon plasma.
The primary changes in a plasma's behavior as it approaches the relativistic regime i
|
https://en.wikipedia.org/wiki/HEV
|
HEV or variation, may refer to:
Transportation
HÉV, a system of suburban railway lines in Budapest, Hungary
Hever railway station (rail code: HEV), in England, UK
Hybrid electric vehicle (HEV)
Hydrogen electric vehicle
Hummer EV (Hev), the GM Hummer electric vehicle, an all-electric offroading pickup truck
Biology
Hendra virus (HeV)
Hepatitis E virus (HEV)
High endothelial venules (HEV)
Hevein (protein) (hev)
Other uses
High-energy visible light
Hazardous Environment Suit, worn by the protagonist of the Half-Life video game series
See also
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https://en.wikipedia.org/wiki/Indian%20Astronomical%20Observatory
|
The Indian Astronomical Observatory (IAO) is a high-altitude astronomy station located in Hanle, India and operated by the Indian Institute of Astrophysics. Situated in the Western Himalayas at an elevation of 4,500 meters (14,764 ft), the IAO is one of the world's highest located sites for optical, infrared and gamma-ray telescopes. It is currently the tenth (see List of highest astronomical observatories) highest optical telescope in the world. It is India's first dark-sky preserve.
Location
The Indian Astronomical Observatory stands on Mt. Saraswati, Digpa-ratsa Ri, Hanle in south-eastern Ladakh union territory of India. Accessing the observatory, located near the Chinese border (Line of Actual Control), requires a 250 km long ten-hour drive from Leh city, the headquarter of Leh district. Nyoma, 75 km northwest from Hanle, has an Indian military airbase.
History
In the late 1980s a committee chaired by Prof. B. V. Sreekantan recommended that a national large optical telescope be taken up as a priority project. The search for the site of the observatory was taken up in 1992 under the leadership of Prof. Arvind Bhatnagar. The scientists from the Indian Institute of Astrophysics found the site at Hanle.
The first light was seen by the Observatory 2-metre telescope on the midnight hour between 26 September and 27 September 2000.
The satellite link between the Centre for Research and Education in Science and Technology (CREST), Bangalore and Hanle was inaugurated by the th
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https://en.wikipedia.org/wiki/Residual%20stress
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In materials science and solid mechanics, residual stresses are stresses that remain in a solid material after the original cause of the stresses has been removed. Residual stress may be desirable or undesirable. For example, laser peening imparts deep beneficial compressive residual stresses into metal components such as turbine engine fan blades, and it is used in toughened glass to allow for large, thin, crack- and scratch-resistant glass displays on smartphones. However, unintended residual stress in a designed structure may cause it to fail prematurely.
Residual stresses can result from a variety of mechanisms including inelastic (plastic) deformations, temperature gradients (during thermal cycle) or structural changes (phase transformation). Heat from welding may cause localized expansion, which is taken up during welding by either the molten metal or the placement of parts being welded. When the finished weldment cools, some areas cool and contract more than others, leaving residual stresses. Another example occurs during semiconductor fabrication and microsystem fabrication when thin film materials with different thermal and crystalline properties are deposited sequentially under different process conditions. The stress variation through a stack of thin film materials can be very complex and can vary between compressive and tensile stresses from layer to layer.
Applications
While uncontrolled residual stresses are undesirable, some designs rely on them. In particu
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https://en.wikipedia.org/wiki/HGA
|
HGA can stand for:
Hammel, Green and Abrahamson, an architecture firm
Handweavers Guild of America
Holy Guardian Angel, a religious term
High-gain antenna, for radio
Human granulocytic anaplasmosis, a disease
Hargeisa Airport
Human Genetics Alert, originally Campaign Against Human Genetic Engineering
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https://en.wikipedia.org/wiki/James%20Collip
|
James Bertram Collip (November 20, 1892 – June 19, 1965) was a Canadian biochemist who was part of the Toronto group which isolated insulin. He served as the chair of the department of biochemistry at McGill University from 1928 to 1941 and dean of medicine at the University of Western Ontario from 1947 to 1961, where he was a charter member of The Kappa Alpha Society.
Education
Born in Belleville, Ontario, he enrolled at Trinity College at the University of Toronto at the age of 15, and studied physiology and biochemistry. He obtained a Ph.D. in biochemistry from the same university in 1916.
Career
In 1915, at the age of 22, Collip accepted a lecturing position in Edmonton in the department of physiology at the University of Alberta Faculty of Medicine, shortly before completing his doctorate. He fulfilled the role for 7 years, eventually rising to the position of professor and head of the department of biochemistry in 1922. His research at the time was mainly focused on blood chemistry of vertebrates and invertebrates.
He took a sabbatical leave beginning in April 1921, and travelled to Toronto on a Rockefeller Travelling Scholarship for a six-month position with Professor John MacLeod of the University of Toronto's department of physiology. There his research program (on the effect of pH on the concentration of sugar in the blood) would take him to the Marine Biological Laboratory in Woods Hole, Massachusetts, and St. Andrews Biological Station in Saint Andrews, New B
|
https://en.wikipedia.org/wiki/Elliptic%20filter
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An elliptic filter (also known as a Cauer filter, named after Wilhelm Cauer, or as a Zolotarev filter, after Yegor Zolotarev) is a signal processing filter with equalized ripple (equiripple) behavior in both the passband and the stopband. The amount of ripple in each band is independently adjustable, and no other filter of equal order can have a faster transition in gain between the passband and the stopband, for the given values of ripple (whether the ripple is equalized or not). Alternatively, one may give up the ability to adjust independently the passband and stopband ripple, and instead design a filter which is maximally insensitive to component variations.
As the ripple in the stopband approaches zero, the filter becomes a type I Chebyshev filter. As the ripple in the passband approaches zero, the filter becomes a type II Chebyshev filter and finally, as both ripple values approach zero, the filter becomes a Butterworth filter.
The gain of a lowpass elliptic filter as a function of angular frequency ω is given by:
where Rn is the nth-order elliptic rational function (sometimes known as a Chebyshev rational function) and
is the cutoff frequency
is the ripple factor
is the selectivity factor
The value of the ripple factor specifies the passband ripple, while the combination of the ripple factor and the selectivity factor specify the stopband ripple.
Properties
In the passband, the elliptic rational function varies between zero and unity. The gain of the passb
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https://en.wikipedia.org/wiki/False%20statement
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A false statement is a statement that is not true. Although the word fallacy is sometimes used as a synonym for false statement, that is not how the word is used in philosophy, mathematics, logic and most formal contexts.
A false statement does not need to be a lie. A lie is a statement that is known to be untrue and is used to mislead. A false statement is a statement that is untrue but not necessarily told to mislead, as a statement given by someone who does not know it is untrue.
Examples of false statements
Misleading statement (lie)
John told his little brother that sea otters aren't mammals, but fish, even though John himself was a marine biologist and knew otherwise. John simply wanted to see his little brother fail his class report, in order to teach him to begin projects early, which help him develop skills necessary to succeed in life.
Statement made out of ignorance
James, John's brother, stated in his class report that sea otters were fish. James got an F after his teacher pointed out why that statement was false. James did not know that sea otters were in fact mammals because he heard that sea otters were fish from his older brother John, a marine biologist.
In law
In some jurisdictions, false statement is a crime similar to perjury.
United States
In U.S. law, a "false statement" generally refers to United States federal false statements statute, contained in . Most commonly, prosecutors use this statute to reach cover-up crimes such as perjury, false decla
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https://en.wikipedia.org/wiki/Repressor
|
In molecular genetics, a repressor is a DNA- or RNA-binding protein that inhibits the expression of one or more genes by binding to the operator or associated silencers. A DNA-binding repressor blocks the attachment of RNA polymerase to the promoter, thus preventing transcription of the genes into messenger RNA. An RNA-binding repressor binds to the mRNA and prevents translation of the mRNA into protein. This blocking or reducing of expression is called repression.
Function
If an inducer, a molecule that initiates the gene expression, is present, then it can interact with the repressor protein and detach it from the operator. RNA polymerase then can transcribe the message (expressing the gene). A co-repressor is a molecule that can bind to the repressor and make it bind to the operator tightly, which decreases transcription.
A repressor that binds with a co-repressor is termed an aporepressor or inactive repressor. One type of aporepressor is the trp repressor, an important metabolic protein in bacteria. The above mechanism of repression is a type of a feedback mechanism because it only allows transcription to occur if a certain condition is present: the presence of specific inducer(s). In contrast, an active repressor binds directly to an operator to repress gene expression.
While repressors are more commonly found in prokaryotes, they are rare in eukaryotes. Furthermore, most known eukaryotic repressors are found in simple organisms (e,g. yeast), and act by interactin
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https://en.wikipedia.org/wiki/Classical%20Heisenberg%20model
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The Classical Heisenberg model, developed by Werner Heisenberg, is the case of the n-vector model, one of the models used in statistical physics to model ferromagnetism, and other phenomena.
Definition
It can be formulated as follows: take a d-dimensional lattice, and a set of spins of the unit length
,
each one placed on a lattice node.
The model is defined through the following Hamiltonian:
with
a coupling between spins.
Properties
The general mathematical formalism used to describe and solve the Heisenberg model and certain generalizations is developed in the article on the Potts model.
In the continuum limit the Heisenberg model (2) gives the following equation of motion
This equation is called the continuous classical Heisenberg ferromagnet equation or shortly Heisenberg model and is integrable in the sense of soliton theory. It admits several integrable and nonintegrable generalizations like Landau-Lifshitz equation, Ishimori equation and so on.
One dimension
In case of long range interaction, , the thermodynamic limit is well defined if ; the magnetization remains zero if ; but the magnetization is positive, at low enough temperature, if (infrared bounds).
As in any 'nearest-neighbor' n-vector model with free boundary conditions, if the external field is zero, there exists a simple exact solution.
Two dimensions
In the case of long-range interaction, , the thermodynamic limit is well defined if ; the magnetization remains zero if ; but the magneti
|
https://en.wikipedia.org/wiki/Bernd%20Pischetsrieder
|
Bernd Peter Pischetsrieder (born 15 February 1948) is a German automobile engineer and manager.
Early life and education
Pischetsrieder was born in Munich, Bavaria, and studied Mechanical Engineering at the Technical University of Munich from 1968 to 1972. He earned the degree of Diplom-Ingenieur.
Career
BMW
Pischetsrieder began his career at BMW in 1973 as a production planning engineer. He was promoted to become chairman of the board of BMW from 1993 through 1999.
During his time as head of BMW, Pischetsrieder was known for solidifying the company's position as a leader in the luxury car market with a solid sporting and engineering reputation. His decision in 1994 to purchase Rover Group from British Aerospace was widely regarded as a failure on paper. Although many of the assets were sold at vast profit and the purchase brought the valuable Mini and Land Rover marques into BMW ownership, the Rover passenger car operation drained the company's coffers. Rover was sold off in 2000, with Ford taking on Land Rover, and the Mini brand remaining at BMW. A more lasting achievement was the assumption of the Rolls-Royce marque, a deal which left rival Volkswagen Group manager, Ferdinand Piëch, with only the Bentley marque, and the Crewe factory. However, this operation has turned out to be much more successful than the Rolls-Royce operation, and it is a matter of debate whether BMW would have been better off keeping Bentley rather than having to take a licence for the Rolls-Ro
|
https://en.wikipedia.org/wiki/Greg%20Lynn
|
Greg Lynn (born 1964) is an American architect, founder and owner of the Greg Lynn FORM office, an o. University Professor in the Institute of Architecture at the University of Applied Arts Vienna and a professor at the UCLA School of the Arts and Architecture. He is CEO and co-founder of the Boston based robotics company Piaggio Fast Forward. He won a Golden Lion at the 2008 Venice Biennale of Architecture. In 2010 Lynn was named a fellow by United States Artists. He is a member of the board of trustees of the Canadian Centre for Architecture.
Life and works
Lynn was born in North Olmsted, Ohio, and claims always to have wanted to be an architect. "When I was twelve, I could already construct perspective drawings and draw axonometric projections", says Lynn. "In high school, someone taught drafting and in the first day of class they saw that I could do all these constructed drawings. I started picking oddly-shaped objects like threaded cones and I would try to draw them in two-point perspective. I got into drawing as a kind of sport." Lynn graduated cum laude from Miami University in Ohio with degrees in architecture and philosophy and from Princeton University School of Architecture with a Master of Architecture. He is distinguished for his use of computer-aided design to produce irregular, biomorphic architectural forms, as he proposes that with the use of computers, calculus can be implemented into the generation of architectural expression. Lynn has written extensively
|
https://en.wikipedia.org/wiki/Connection
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Connection may refer to:
Mathematics
Connection (algebraic framework)
Connection (mathematics), a way of specifying a derivative of a geometrical object along a vector field on a manifold
Connection (affine bundle)
Connection (composite bundle)
Connection (fibred manifold)
Connection (principal bundle), gives the derivative of a section of a principal bundle
Connection (vector bundle), differentiates a section of a vector bundle along a vector field
Cartan connection, achieved by identifying tangent spaces with the tangent space of a certain model Klein geometry
Ehresmann connection, gives a manner for differentiating sections of a general fibre bundle
Electrical connection, allows the flow of electrons
Galois connection, a type of correspondence between two partially ordered sets
Affine connection, a geometric object on a smooth manifold which connects nearby tangent spaces
Levi-Civita connection, used in differential geometry and general relativity; differentiates a vector field along another vector field
Music
Connection (The Green Children album), 2013
Connection (Don Ellis album), 1972
Connection (Up10tion album), 2021
Connection (EP), a 2000 split EP by Home Grown and Limbeck
Connection, a 2019 EP by Seyong
"Connection" (Elastica song) (1994)
"Connection" (OneRepublic song) (2018)
"Connection" (Rolling Stones song) (1967)
"Connection", a song by Avail from Satiate
"Connection", a 1976 song by Can from Unlimited Edition
"Connection", a song by the Kooks from 10 Tracks
|
https://en.wikipedia.org/wiki/Nernst%20effect
|
In physics and chemistry, the Nernst effect (also termed first Nernst–Ettingshausen effect, after Walther Nernst and Albert von Ettingshausen) is a thermoelectric (or thermomagnetic) phenomenon observed when a sample allowing electrical conduction is subjected to a magnetic field and a temperature gradient normal (perpendicular) to each other. An electric field will be induced normal to both.
This effect is quantified by the Nernst coefficient , which is defined to be
where is the y-component of the electric field that results from the magnetic field's z-component and the x-component of the temperature gradient .
The reverse process is known as the Ettingshausen effect and also as the second Nernst–Ettingshausen effect.
Physical picture
Mobile energy carriers (for example conduction-band electrons in a semiconductor) will move along temperature gradients due to statistics and the relationship
between temperature and kinetic energy. If there is a magnetic field transversal to the temperature gradient and the carriers are electrically charged, they experience a force perpendicular to their direction of motion (also the direction of the temperature gradient) and to the magnetic field. Thus, a perpendicular electric field is induced.
Sample types
Semiconductors exhibit the Nernst effect. This has been studied in the 1950s by Krylova, Mochan and many others. In metals however, it is almost non-existent. It appears in the vortex phase
of type-II superconductors due to vo
|
https://en.wikipedia.org/wiki/2%2C2%2C6%2C6-Tetramethylpiperidine
|
2,2,6,6-Tetramethylpiperidine, abbreviated TMP, HTMP, or TMPH, is an organic compound of the amine class. In appearance, it is a colorless liquid and has a "fishy", amine-like odor. This amine is used in chemistry as a hindered base (hindered amine). Although TMP finds limited use per se, its derivatives are a mainstay of hindered amine light stabilizers.
TMP is the starting material for an even stronger base, lithium tetramethylpiperidide and the radical species TEMPO. Another non-nucleophilic base is N,N-diisopropylethylamine. Its aqueous pKaH (conjugate acid dissociation constant, a measure of basicity) is 11.07 at 25 °C, while its pKa (acid dissociation constant, a measure of acidity) is approximately 37.
Preparation
Many routes for the synthesis of TMP have been reported. One method starts with a conjugate addition reaction of ammonia to phorone. The intermediate triacetone amine is then reduced in a Wolff-Kishner reaction.
See also
2,6-Dimethylpiperidine
Pempidine
TEMPO ((2,2,6,6-Tetramethylpiperidin-1-yl)oxyl)
References
External links
DataSheet I
DataSheet II
TMP applied in synthesis in Organic Syntheses
Piperidines
Reagents for organic chemistry
Non-nucleophilic bases
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https://en.wikipedia.org/wiki/Telluride%20%28chemistry%29
|
The telluride ion is the anion Te2− and its derivatives. It is analogous to the other chalcogenide anions, the lighter O2−, S2−, and Se2−, and the heavier Po2−.
In principle, Te2− is formed by the two-e− reduction of tellurium. The redox potential is −1.14 V.
Te(s) + 2 e− ↔ Te2−
Although solutions of the telluride dianion have not been reported, soluble salts of bitelluride (TeH−) are known.
Organic tellurides
Tellurides also describe a class of organotellurium compounds formally derived from Te2−. An illustrative member is dimethyl telluride, which results from the methylation of telluride salts:
2 CH3I + Na2Te → (CH3)2Te + 2 NaI
Dimethyl telluride is formed by the body when tellurium is ingested. Such compounds are often called telluroethers because they are structurally related to ethers with tellurium replacing oxygen, although the length of the C–Te bond is much longer than a C–O bond. C–Te–C angles tend to be closer to 90°.
Inorganic tellurides
Many metal tellurides are known, including some telluride minerals. These include natural gold tellurides, like calaverite and krennerite (AuTe2), and sylvanite (AgAuTe4). They are minor ores of gold, although they comprise the major naturally occurring compounds of gold. (A few other natural compounds of gold, such as the bismuthide maldonite (Au2Bi) and antimonide aurostibite (AuSb2), are known). Although the bonding in such materials is often fairly covalent, they are described casually as salts of Te2−. Using this
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https://en.wikipedia.org/wiki/Hamming%20bound
|
In mathematics and computer science, in the field of coding theory, the Hamming bound is a limit on the parameters of an arbitrary block code: it is also known as the sphere-packing bound or the volume bound from an interpretation in terms of packing balls in the Hamming metric into the space of all possible words. It gives an important limitation on the efficiency with which any error-correcting code can utilize the space in which its code words are embedded. A code that attains the Hamming bound is said to be a perfect code.
Background on error-correcting codes
An original message and an encoded version are both composed in an alphabet of q letters. Each code word contains n letters. The original message (of length m) is shorter than n letters. The message is converted into an n-letter codeword by an encoding algorithm, transmitted over a noisy channel, and finally decoded by the receiver. The decoding process interprets a garbled codeword, referred to as simply a word, as the valid codeword "nearest" the n-letter received string.
Mathematically, there are exactly qm possible messages of length m, and each message can be regarded as a vector of length m. The encoding scheme converts an m-dimensional vector into an n-dimensional vector. Exactly qm valid codewords are possible, but any one of qn words can be received because the noisy channel might distort one or more of the n letters when a codeword is transmitted.
Statement of the bound
Preliminary definitions
An alph
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https://en.wikipedia.org/wiki/Peter%20Barham
|
Peter Barham (born 1950) is emeritus professor of physics at the University of Bristol. He was visiting professor of Molecular Gastronomy at the University of Copenhagen, Denmark.
Early life
Peter Barham was born in 1950. He received his BSc from the University of Warwick, and his MSc and PhD from the University of Bristol.
Career
Peter Barham's research at the University of Bristol is concerned with polymer physics. He found ways to connect his research with his love of penguins, including the creation of silicon-based flipper bands which can be used for monitoring penguin populations. The silicone bands are designed to minimize the potential impact of carrying an external marking device and are currently in use on African penguins (Spheniscus demersus) at Bristol Zoo, UK and in the wild in South Africa. More recently, together with colleagues in the Computer Science Department at the University of Bristol, he has developed a computer vision system for the automatic recognition of African penguins. This system in 2008 was undergoing trials in South Africa.
Barham has contributed to the development of the new science of molecular gastronomy and has authored the book The Science of Cooking (). He has collaborated with a number of chefs including Heston Blumenthal, the chef/owner of The Fat Duck and also a proponent of molecular gastronomy. He is editor-in-chief of a new journal, Flavour, which covers the science of molecular gastronomy. In 1994 he appeared as the Scientific
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