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https://en.wikipedia.org/wiki/Personal%20equation | The term personal equation, in 19th- and early 20th-century science, referred to the idea that different observers have different reaction times, which can introduce bias when it comes to measurements and observations.
Astronomy
The term originated in astronomy, when it was discovered that numerous observers making simultaneous observations would record slightly different values (for example, in recording the exact time at which a star crossed the wires of a reticule in a telescope), some of which were of a significant enough difference to afford for problems in larger calculations.
The existence of the effect was first discovered when, in 1796, the Astronomer Royal Neville Maskelyne dismissed his assistant Kinnebrooke because he could not better the error of his observations relative to Maskelyne's own values. The problem was forgotten and only analysed two decades later by Friedrich Wilhelm Bessel at Königsberg Observatory in Prussia. Setting up an experiment to compare the values, Bessel and an assistant measured the times at which several stars crossed the wires of a reticule in different nights. Compared to his assistant, Bessel found himself to be ahead by more than a second.
In response to this realization, astronomers became increasingly suspicious of the results of other astronomers and their own assistants and began systematic programs to attempt to find ways to remove or lessen the effects. These included attempts at the automation of observations (appealing to the presumed objectivity of machines), training observers to try to avoid certain known errors (such as those caused by lack of sleep), developing machines that could allow multiple observers to make observations at the same time, the taking of redundant data and using techniques such as the method of least squares to derive possible values from them, and trying to quantify the biases of individual workers so that they could be subtracted from the data. It became a major topic in experimental p |
https://en.wikipedia.org/wiki/SIESTA%20%28computer%20program%29 | SIESTA (Spanish Initiative for Electronic Simulations with Thousands of Atoms) is an original method and its computer program implementation, to efficiently perform electronic structure calculations and ab initio molecular dynamics simulations of molecules and solids. SIESTA uses strictly localized basis sets and the implementation of linear-scaling algorithms. Accuracy and speed can be set in a wide range, from quick exploratory calculations to highly accurate simulations matching the quality of other approaches, such as the plane-wave and all-electron methods.
SIESTA's backronym is the Spanish Initiative for Electronic Simulations with Thousands of Atoms.
Since 13 May 2016, with the 4.0 version announcement, SIESTA is released under the terms of the GPL open-source license. Source packages and access to the development versions can be obtained from the DevOps platform on GitLab. The latest version Siesta-4.1.5 was released on 4 February 2021.
Features
SIESTA has these main characteristics:
It uses the standard Kohn-Sham self-consistent density functional method in the local density (LDA-LSD) and generalized gradient (GGA) approximations, as well as in a non-local function that includes van der Waals interactions (VDW-DF).
It uses norm-conserving pseudopotentials in their fully non-local (Kleinman-Bylander) form.
It uses atomic orbitals as a basis set, allowing unlimited multiple-zeta and angular momenta, polarization, and off-site orbitals. The radial shape of every orbital is numerical, and any shape can be used and provided by the user, with the only condition that it has to be of finite support, i.e., it has to be strictly zero beyond a user-provided distance from the corresponding nucleus. Finite-support basis sets are the key to calculating the Hamiltonian and overlap matrices in O(N) operations.
Projects the electron wave functions and density onto a real-space grid to calculate the Hartree and exchange-correlation potentials and their matrix element |
https://en.wikipedia.org/wiki/John%20S.%20Rodwell | John S. Rodwell (1946 – present) is an ecologist who was based at the University of Lancaster, noted for his role in the development of the British National Vegetation Classification and as editor of the five volumes of British Plant Communities.
Education
Rodwell graduated in Botany from the University of Leeds in 1968, then researched limestone vegetation at the University of Southampton under Joyce Lambert for his PhD in Biology, awarded in 1974. He also trained for the priesthood at Ripon College Cuddesdon, University of Oxford, maintaining this vocation as a non-stipendiary priest since 1974 in the Diocese of Blackburn since 1975 and is honorary canon of Blackburn Cathedral.
Career
In the same year, 1975, he became co-ordinator of research leading to the development of the British National Vegetation Classification (NVC). at Lancaster University, becoming editor of the NVC, a task that dominated his working life for more than two decades. All five volumes of British Plant Communities, which describe the NVC, were edited by Rodwell.
He joined the faculty of Lancaster University in 1991, was made Professor of Ecology in 1997 and retired in 2004 but has continued to teach and publish since then. In 2009 he was awarded the Institute of Ecology and Environmental Management medal of honour.
He is a Honorary Member of the International Association for Vegetation Science (2010). |
https://en.wikipedia.org/wiki/Pork%20and%20beans | Pork and beans is a culinary dish that uses pork and beans as its main ingredients. Numerous variations exist, usually with more specific names, such as Fabada Asturiana, Olla podrida, or American canned pork and beans.
American canned pork and beans
Although the time and place of the first appearance of American canned pork and beans is unclear, the dish was well established in the American diet by the mid-19th century. The 1832 cookbook The American Frugal Housewife lists only three ingredients for pork and beans: a quart of beans, a pound of salt pork, and pepper. Commercially canned pork and beans were introduced in the United States sometime around 1880. According to the 1975 Better Homes and Garden Heritage Cookbook, canned pork and beans was the first convenience food.
Today, the dish is "an American canned classic, [and] is recognized by American consumers generally as an article of commerce that contains very little pork."
The recipe for American commercially canned pork and beans varies slightly from company to company, but generally consists of rehydrated navy beans packed in tomato sauce (usually made from concentrate and which may incorporate starch, sugar, salt, and seasoning), with very small chunks of salt pork or rendered pork fat. The ingredients are cooked, packed into hermetically sealed containers, and processed by heat to assure preservation.
See also
Baked beans
Beans and franks
Boston baked beans
Cowboy beans
Feijoada
Cassoulet
List of pork dishes
List of stews |
https://en.wikipedia.org/wiki/Intel%20GMA | The Intel Graphics Media Accelerator (GMA) is a series of integrated graphics processors introduced in 2004 by Intel, replacing the earlier Intel Extreme Graphics series and being succeeded by the Intel HD and Iris Graphics series.
This series targets the market of low-cost graphics solutions. The products in this series are integrated onto the motherboard, have limited graphics processing power, and use the computer's main memory for storage instead of a dedicated video memory. They were commonly found on netbooks, low-priced laptops and desktop computers, as well as business computers which do not need high levels of graphics capability. In early 2007, about 90% of all PC motherboards sold had an integrated GPU.
History
The GMA line of GPUs replaces the earlier Intel Extreme Graphics, and the Intel740 line, the latter of which was a discrete unit in the form of AGP and PCI cards with technology that evolved from companies Real3D and Lockheed Martin. Later, Intel integrated the i740 core into the Intel 810 northbridge.
The original architecture of GMA systems supported only a few functions in hardware, and relied on the host CPU to handle at least some of the graphics pipeline, further decreasing performance. However, with the introduction of Intel's 4th generation of GMA architecture (GMA X3000) in 2006, many of the functions are now built into the hardware, providing an increase in performance. The 4th generation of GMA combines fixed function capabilities with a threaded array of programmable executions units, providing advantages to both graphics and video performance. Many of the advantages of the new GMA architecture come from the ability to flexibly switch as needed between executing graphics-related tasks or video-related tasks. While GMA performance has been widely criticized in the past as being too slow for computer games, sometimes being derogatorily nicknamed Intel 'GMD' (Graphics Media Decelerator) and being essentially referred to as the world's |
https://en.wikipedia.org/wiki/Succubous | Succubous is a manner in which the leaves of a liverwort overlap. If one were to look down from above (dorsal side) on a plant where the leaf attachment is succubous, the upper edge of each leaf would be covered by the next leaf along the stem. The lower edge of each leaf is visible from above, but the edge of the leaf closer to the tip of the stem is obscured by a neighboring leaf. The opposite of succubous is incubous. |
https://en.wikipedia.org/wiki/Equipotential | In mathematics and physics, an equipotential or isopotential refers to a region in space where every point is at the same potential. This usually refers to a scalar potential (in that case it is a level set of the potential), although it can also be applied to vector potentials. An equipotential of a scalar potential function in -dimensional space is typically an ()-dimensional space. The del operator illustrates the relationship between a vector field and its associated scalar potential field. An equipotential region might be referred as being 'of equipotential' or simply be called 'an equipotential'.
An equipotential region of a scalar potential in three-dimensional space is often an equipotential surface (or potential isosurface), but it can also be a three-dimensional mathematical solid in space. The gradient of the scalar potential (and hence also its opposite, as in the case of a vector field with an associated potential field) is everywhere perpendicular to the equipotential surface, and zero inside a three-dimensional equipotential region.
Electrical conductors offer an intuitive example. If a and b are any two points within or at the surface of a given conductor, and given there is no flow of charge being exchanged between the two points, then the potential difference is zero between the two points. Thus, an equipotential would contain both points a and b as they have the same potential. Extending this definition, an isopotential is the locus of all points that are of the same potential.
Gravity is perpendicular to the equipotential surfaces of the gravity potential, and in electrostatics and steady electric currents, the electric field (and hence the current, if any) is perpendicular to the equipotential surfaces of the electric potential (voltage).
In gravity, a hollow sphere has a three-dimensional equipotential region inside, with no gravity from the sphere (see shell theorem). In electrostatics, a conductor is a three-dimensional equipotential reg |
https://en.wikipedia.org/wiki/Incubous | The term incubous describes the way in which the leaves of a liverwort are attached to the stem. If one were to look down from above (dorsal side) on a plant where the leaf attachment is incubous, the upper edge of each leaf would overlap the next higher leaf along the stem. Because of this, the upper edge of each leaf is visible from above, but the lower edge of each leaf is obscured by its neighboring leaf. The opposite of incubous is succubous. |
https://en.wikipedia.org/wiki/Molecular%20Biology%20%28journal%29 | Molecular Biology is a scientific journal which covers a wide scope of problems related to molecular, cell, and computational biology including genomics, proteomics, bioinformatics, molecular virology and immunology, molecular development biology, and molecular evolution. Molecular Biology publishes reviews, mini-reviews, experimental, and theoretical works, short communications and hypotheses. In addition, the journal publishes book reviews and meeting reports. The journal also publishes special issues devoted to most rapidly developing branches of physical-chemical biology and to the most outstanding scientists on the occasion of their anniversary birthdays. The journal is published in English and Russian versions by Nauka.
External links
Molecular and cellular biology journals
Multilingual journals
Publications with year of establishment missing
Nauka academic journals
English-language journals
Russian-language journals
Springer Science+Business Media academic journals |
https://en.wikipedia.org/wiki/Uhthoff%27s%20phenomenon | Uhthoff's phenomenon (also known as Uhthoff's syndrome, Uhthoff's sign, and Uhthoff's symptom) is the worsening of neurologic symptoms in multiple sclerosis (MS) and other demyelinating diseases when the body is overheated. This may occur due to hot weather, exercise, fever, saunas, hot tubs, hot baths, and hot food and drink. Increased temperature slows nerve conduction, but the exact mechanism remains unknown. With an increased body temperature, nerve impulses are either blocked or slowed in a damaged nerve. Once the body temperature is normalized, signs and symptoms typically reverse.
Signs and symptoms
Symptoms of Uhthoff's phenomenon occur when exposed to heat, and include:
fatigue
pain
concentration difficulties
urinary urgency
worsen of existing optic neuropathy (although optic neuropathy may occur for the first time)
muscle stiffness
dizziness and unsteadiness
Causes
Uhthoff's phenomenon is caused by a raised body temperature. This may be caused by:
hot weather
exercise
fever
saunas
sun tanning
hot tubs, and hot baths and showers
hot food and drink
menstruation (which may raise body temperature)
sitting near a radiator
Mechanism
The exact mechanism of Uhthoff's phenomenon is unknown. It causes a decrease in the speed of action potentials in the central nervous system (CNS). Heat may increase the time when voltage-gated sodium channels are inactivated, which delays further action potentials. This is worsened by the demyelination caused by MS. Other theories have considered the role of heat shock proteins and changes to blood flow.
Peripheral nerve studies have shown that even a 0.5 °C increase in body temperature can slow or block the conduction of nerve impulses in demyelinated nerves. With greater levels of demyelination, a smaller increase in temperature is needed to slow down the nerve impulse conduction. Exercising and normal daily activities can cause a significant increase in body temperature in individuals with MS, especially if |
https://en.wikipedia.org/wiki/M1%20protein | The M1 protein is a matrix protein of the influenza virus. It forms a coat inside the viral envelope. This is a bifunctional membrane/RNA-binding protein that mediates the encapsidation of nucleoprotein cores into the membrane envelope. It is therefore required that M1 binds both membrane and RNA simultaneously.
The M1 protein binds to the viral RNA. The binding is not specific to any RNA sequence, and is performed via a peptide sequence rich in basic amino acids.
It also has multiple regulatory functions, performed by interaction with the components of the host cell. The mechanisms regulated include a role in the export of the viral ribonucleoproteins from the host cell nucleus, inhibition of viral transcription, and a role in the virus assembly and budding. The protein was found to undergo phosphorylation in the host cell.
The M1 protein forms a layer under the patches of host cell membrane that are rich with the viral hemagglutinin, neuraminidase and M2 transmembrane proteins, and facilitates budding of the mature viruses.
M1 consists of two domains connected by a linker sequence. The N-terminal domain has a multi-helical structure that can be divided into two subdomains. The C-terminal domain also contains alpha-helical structure.
See also
H5N1 genetic structure
Sources and notes
Membrane biology
Peripheral membrane proteins
Influenza A virus
Viral structural proteins |
https://en.wikipedia.org/wiki/Calculator%20watch | A calculator watch is a digital watch with a built-in calculator, usually including buttons on the watch face. Calculator watches were first introduced in the 1970s and continue to be produced, despite falling from their peak popularity during the 1980s. The most dominant brands were the Casio Databank series and Timex.
Most calculator watches perform only basic arithmetic operations (addition, subtraction, multiplication, and division). However, there are several models with additional functions: scientific, including transcendent and trigonometry, in models Casio CFX-20, CFX-200, CFX-400 and Citizen 49–9421, financial functions (Casio CBA-10) and also TV remote control functions (CMD-40B and CMD-30B).
Usually, calculator watches operate with eight-digit numbers; however, calculator watches can work with six digits (for example, Casio C-801) or ten-digit (Casio CBA-10).
History
Calculator watches first appeared in the mid-1970s introduced by Pulsar (1975, then a brand of the Hamilton Watch Company) and Hewlett-Packard.
Another popular calculator watch was the Time Computer Calculator 901, which could perform basic arithmetic functions. The 902 models had additional functions such as percentage calculations. The Time watches carried a high price tag (US$4,000) because they were made of solid gold and operated by a stylus pen owing to the small size of their buttons.
Popular watches include those from Seiko and Citizen, some of which had innovative functions.
Japanese electronics company Casio produced the widest variety of watches. In the mid-1980s, Casio created the Databank calculator watch, which performed calculator functions and stored appointments, names, addresses, and phone numbers. The calculator watches made by Casio earned much fame due to their appearance in movies and also due to being celebrities' choice during public events.
Mass-produced calculator watches appeared in the early 1980s, with the most being produced in the middle of the decade. |
https://en.wikipedia.org/wiki/Viral%20matrix%20protein | Viral matrix proteins are structural proteins linking the viral envelope with the virus core. They play a crucial role in virus assembly, and interact with the RNP complex as well as with the viral membrane. They are found in many enveloped viruses including paramyxoviruses, orthomyxoviruses, herpesviruses, retroviruses, filoviruses and other groups.
An example is the M1 protein of the influenza virus, showing affinity to the glycoproteins inserted in the host cell membrane on one side and affinity for the RNP complex molecules on the other side, which allows formation at the membrane of a complex made of the viral ribonucleoprotein at the inner side indirectly connected to the viral glycoproteins protruding from the membrane. This assembly complex will now bud out of the cell as new mature viruses.
Viral matrix proteins, like many other viral proteins, can exert different functions during the course of the infection. For example, in rhabdoviruses, binding of M proteins to nucleocapsids is accountable for the formation of its “bullet” shaped virions.
In herpesviruses, the viral matrix is usually called viral tegument and contains many proteins involved in viral entry, early gene expression and immune evasion. |
https://en.wikipedia.org/wiki/237%20%28number%29 | 237 (two hundred [and] thirty-seven) is the natural number following 236 and preceding 238.
237 is a lucky number, and one of the numbers in Aronson's sequence.
The 237th square pyramidal number, 4465475, is also a sum of two smaller square pyramidal numbers. There are only four smaller numbers (55, 70, 147, and 226) with the same property. |
https://en.wikipedia.org/wiki/Posadis | In computing, Posadis is a GPL-licensed DNS server for Microsoft Windows and Unix that uses a zone file format that is compatible with BIND zone files. Posadis is part of a suite which includes graphical configuration and zone file management programs.
Posadis has IPv6 support.
See also
Comparison of DNS server software
External links
Posadis website
DNS software
Cross-platform free software
Free network-related software
DNS server software for Linux |
https://en.wikipedia.org/wiki/SNOPT | SNOPT, for Sparse Nonlinear OPTimizer, is a software package for solving large-scale nonlinear optimization problems written by Philip Gill, Walter Murray and Michael Saunders. SNOPT is mainly written in Fortran, but interfaces to C, C++, Python and MATLAB are available.
It employs a sparse sequential quadratic programming (SQP) algorithm with limited-memory quasi-Newton approximations to the Hessian of the Lagrangian. It is especially effective for nonlinear problems with functions and gradients that are expensive to evaluate. The functions should be smooth but need not be convex.
SNOPT is used in several trajectory optimization software packages, including Copernicus, AeroSpace Trajectory Optimization and Software (ASTOS), General Mission Analysis Tool, and Optimal Trajectories by Implicit Simulation (OTIS). It is also available in the Astrogator module of Systems Tool Kit.
SNOPT is supported in the AIMMS, AMPL, APMonitor, General Algebraic Modeling System (GAMS), and TOMLAB modeling systems. |
https://en.wikipedia.org/wiki/Acoustic%20Doppler%20current%20profiler | An acoustic doppler current profiler (ADCP) is a hydroacoustic current meter similar to a sonar, used to measure water current velocities over a depth range using the Doppler effect of sound waves scattered back from particles within the water column. The term ADCP is a generic term for all acoustic current profilers, although the abbreviation originates from an instrument series introduced by RD Instruments in the 1980s. The working frequencies range of ADCPs range from 38 kHz to several megahertz.
A similar device is a SODAR, which works in the air and uses the same principles for wind speed profiling.
Working principle
ADCPs contain piezoelectric transducers to transmit and receive sound signals. The traveling time of sound waves gives an estimate of the distance. The frequency shift of the echo is proportional to the water velocity along the acoustic path. To measure 3D velocities, at least three beams are required. In rivers, only the 2D velocity is relevant and ADCPs typically have two beams. In recent years, more functionality has been added to ADCPs (notably wave and turbulence measurements) and systems can be found with 2,3,4,5 or even 9 beams.
Further components of an ADCP are an electronic amplifier, a receiver, a clock to measure the traveling time, a temperature sensor, a compass to know the heading, and a pitch/roll sensor to know the orientation. An analog-to-digital converter and a digital signal processor are required to sample the returning signal in order to determine the Doppler shift. A temperature sensor is used to estimate the sound velocity at the instrument position using the seawater equation of state, and uses this to estimate scale the frequency shift to water velocities. This procedure assumes that the salinity has a preconfigured constant value. Finally, the results are saved to internal memory or output online to an external display software.
Processing methods
Three common methods are used to calculate the Doppler shift and |
https://en.wikipedia.org/wiki/List%20of%20planar%20symmetry%20groups | This article summarizes the classes of discrete symmetry groups of the Euclidean plane. The symmetry groups are named here by three naming schemes: International notation, orbifold notation, and Coxeter notation.
There are three kinds of symmetry groups of the plane:
2 families of rosette groups – 2D point groups
7 frieze groups – 2D line groups
17 wallpaper groups – 2D space groups.
Rosette groups
There are two families of discrete two-dimensional point groups, and they are specified with parameter n, which is the order of the group of the rotations in the group.
Frieze groups
The 7 frieze groups, the two-dimensional line groups, with a direction of periodicity are given with five notational names. The Schönflies notation is given as infinite limits of 7 dihedral groups. The yellow regions represent the infinite fundamental domain in each.
Wallpaper groups
The 17 wallpaper groups, with finite fundamental domains, are given by International notation, orbifold notation, and Coxeter notation, classified by the 5 Bravais lattices in the plane: square, oblique (parallelogrammatic), hexagonal (equilateral triangular), rectangular (centered rhombic), and rhombic (centered rectangular).
The p1 and p2 groups, with no reflectional symmetry, are repeated in all classes. The related pure reflectional Coxeter group are given with all classes except oblique.
Wallpaper subgroup relationships
See also
List of spherical symmetry groups
Orbifold notation#Hyperbolic plane - Hyperbolic symmetry groups
Notes |
https://en.wikipedia.org/wiki/Hexagonal%20lattice | The hexagonal lattice (sometimes called triangular lattice) is one of the five two-dimensional Bravais lattice types. The symmetry category of the lattice is wallpaper group p6m. The primitive translation vectors of the hexagonal lattice form an angle of 120° and are of equal lengths,
The reciprocal lattice of the hexagonal lattice is a hexagonal lattice in reciprocal space with orientation changed by 90° and primitive lattice vectors of length
Honeycomb point set
The honeycomb point set is a special case of the hexagonal lattice with a two-atom basis. The centers of the hexagons of a honeycomb form a hexagonal lattice, and the honeycomb point set can be seen as the union of two offset hexagonal lattices.
In nature, carbon atoms of the two-dimensional material graphene are arranged in a honeycomb point set.
Crystal classes
The hexagonal lattice class names, Schönflies notation, Hermann-Mauguin notation, orbifold notation, Coxeter notation, and wallpaper groups are listed in the table below.
See also
Square lattice
Hexagonal tiling
Close-packing
Centered hexagonal number
Eisenstein integer
Voronoi diagram
Hermite constant |
https://en.wikipedia.org/wiki/Anatoliy%20Skorokhod | Anatoliy Volodymyrovych Skorokhod (; September 10, 1930January 3, 2011) was a Soviet and Ukrainian mathematician.
Skorokhod is well-known for a comprehensive treatise on the theory of stochastic processes, co-authored with Gikhman.
Career
Skorokhod worked at Kyiv University from 1956 to 1964. He was subsequently at the Institute of Mathematics of the National Academy of Sciences of Ukraine from 1964 until 2002. Since 1993, he had been a professor at Michigan State University in the US, and a member of the American Academy of Arts and Sciences.
He was an academician of the National Academy of Sciences of Ukraine from 1985 to his death in 2011.
His scientific works are on the theory of:
stochastic differential equations,
limit theorems of random processes,
distributions in infinite-dimensional spaces,
statistics of random processes and Markov processes.
Skorokhod authored over 450 scientific works, including more than 40 monographs and books.
Many terms and concepts have his name, including:
Skorokhod's embedding theorem
Skorokhod integral
Skorokhod's representation theorem
Skorokhod space
Skorokhod problem
Selected works
with I. I. Gikhman: Introduction to the theory of random processes, W. B. Saunders 1969, Dover 1996
with I. I. Gikhman: Stochastic Differential Equations, Springer Verlag 1972
with I. I. Gikhman: Controlled stochastic processes, Springer Verlag 1979
with I. I. Gikhman: The Theory of Stochastic Processes, Springer Verlag, 3 vols., 2004–2007
Random processes with independent increments, Kluwer 1991
Asymptotic methods in the theory of stochastic differential equations , American Mathematical Society 1989
Random linear operators, Reidel 1984
Studies in the theory of random processes, Dover 1982
Stochastic equations for complex systems, Reidel/Kluwer 1988
Stochastische Differentialgleichungen, Berlin, Akademie Verlag 1971
Integration in Hilbert Space, Springer Verlag 1974
with Yu. V. Prokhorov: Basic principles and applications of probab |
https://en.wikipedia.org/wiki/Atovaquone | Atovaquone, sold under the brand name Mepron, is an antimicrobial medication for the prevention and treatment of Pneumocystis jirovecii pneumonia (PCP).
Atovaquone is a chemical compound that belongs to the class of naphthoquinones. Atovaquone is a hydroxy-1,4-naphthoquinone, an analog of both ubiquinone and lawsone.
Medical uses
Atovaquone is a medication used to treat or prevent:
For pneumocystis pneumonia (PCP), it is used in mild cases, although it is not approved for treatment of severe cases.
For toxoplasmosis, the medication has antiparasitic and therapeutic effects.
For malaria, it is one of the two components (along with proguanil) in the drug Malarone. Malarone has fewer side effects and is more expensive than mefloquine. Resistance has been observed.
For babesia, it is often used in conjunction with oral azithromycin.
Trimethoprim/sulfamethoxazole (TMP-SMX, Bactrim) is generally considered first-line therapy for PCP (not to be confused with sulfadiazine and pyrimethamine, which is first line for toxoplasmosis). However, atovaquone may be used in patients who cannot tolerate, or are allergic to, sulfonamide medications such as TMP-SMX. In addition, atovaquone has the advantage of not causing myelosuppression, which is an important issue in patients who have undergone bone marrow transplantation.
Atovaquone is given prophylactically to kidney transplant patients to prevent PCP in cases where Bactrim is contraindicated for the patient.
Malaria
Atovaquone, as a combination preparation with proguanil, has been commercially available from GlaxoSmithKline since 2000 as Malarone for the treatment and prevention of malaria.
Research
COVID-19
Preliminary research found that atovaquone could inhibit the replication of SARS-CoV-2 in vitro. Clinical trials of atovaquone for the treatment of COVID-19 are planned, and ongoing in United States in December 2021.
Atovaquone has also been found to inhibit human coronavirus OC43 and feline coronavirus in vitro. |
https://en.wikipedia.org/wiki/ILIOS | ILIOS is an acronym of InterLink Internet Operating System. It is an attempt to create a router-only operating system; one specifically oriented towards computer networking purposes, especially routing. It supports IPv4 routing and is a good educational OS, though it is single tasking and does everything via interrupts.
It is released under the BSD License. The author of this research OS is Rink Springer, who is also responsible for porting FreeBSD to the Xbox.
External links
ILIOS - Trac Rink Springer's website
Free software operating systems
Software using the BSD license |
https://en.wikipedia.org/wiki/M32R | The M32R is a 32-bit RISC instruction set architecture (ISA) developed by Mitsubishi Electric for embedded microprocessors and microcontrollers. The ISA is now owned by Renesas Electronics Corporation, and the company designs and fabricates M32R implementations. M32R processors are used in embedded systems such as Engine Control Units, digital cameras and PDAs. The ISA was supported by Linux and the GNU Compiler Collection but was dropped in Linux kernel version 4.16. GCC removed support for this architecture in the GCC 12.1 release. |
https://en.wikipedia.org/wiki/Temporary%20variable | In computer programming, a temporary variable is a variable with short lifetime, usually to hold data that will soon be discarded, or before it can be placed at a more permanent memory location. Because it is short-lived, it is usually declared as a local variable, i.e., a variable with local scope. There is no formal definition of what makes a variable temporary, but it is an often-used term in programming.
A typical example would be that of swapping the contents of two variables. Temporary variables, along with XOR swaps and arithmetic operators, are one of three main ways to exchange the contents of two variables. To swap the contents of variables "a" and "b" one would typically use a temporary variable temp as follows, so as to preserve the data from a as it is being overwritten by b:
temp := a
a := b
b := temp
Temporary variables are usually named with identifiers that abbreviate the word temporary, such as temp, tmp or simply t, or
with common metasyntactic variable names, the most common of which are foo, bar, baz (see also foobar).
Computer hardware is designed to exploit the behaviour of temporary data: a cache or register file may contain temporaries internally to a microprocessor, such that they never need to be committed to main memory (hence consuming no external memory bandwidth).
See also
Temporary folder
Temporary file
Temporary filesystem
Variable (computer science) |
https://en.wikipedia.org/wiki/Wandering%20set | In dynamical systems and ergodic theory, the concept of a wandering set formalizes a certain idea of movement and mixing. When a dynamical system has a wandering set of non-zero measure, then the system is a dissipative system. This is the opposite of a conservative system, to which the Poincaré recurrence theorem applies. Intuitively, the connection between wandering sets and dissipation is easily understood: if a portion of the phase space "wanders away" during normal time-evolution of the system, and is never visited again, then the system is dissipative. The language of wandering sets can be used to give a precise, mathematical definition to the concept of a dissipative system. The notion of wandering sets in phase space was introduced by Birkhoff in 1927.
Wandering points
A common, discrete-time definition of wandering sets starts with a map of a topological space X. A point is said to be a wandering point if there is a neighbourhood U of x and a positive integer N such that for all , the iterated map is non-intersecting:
A handier definition requires only that the intersection have measure zero. To be precise, the definition requires that X be a measure space, i.e. part of a triple of Borel sets and a measure such that
for all . Similarly, a continuous-time system will have a map defining the time evolution or flow of the system, with the time-evolution operator being a one-parameter continuous abelian group action on X:
In such a case, a wandering point will have a neighbourhood U of x and a time T such that for all times , the time-evolved map is of measure zero:
These simpler definitions may be fully generalized to the group action of a topological group. Let be a measure space, that is, a set with a measure defined on its Borel subsets. Let be a group acting on that set. Given a point , the set
is called the trajectory or orbit of the point x.
An element is called a wandering point if there exists a neighborhood U of x and a neighborh |
https://en.wikipedia.org/wiki/Bell%27s%20spaceship%20paradox | Bell's spaceship paradox is a thought experiment in special relativity. It was first described by E. Dewan and M. Beran in 1959 but became more widely known after John Stewart Bell elaborated the idea further in 1976. A delicate thread hangs between two spaceships headed in the same direction. They start accelerating simultaneously and equally as measured in the inertial frame S, thus having the same velocity at all times as viewed from S. Therefore, they are all subject to the same Lorentz contraction, so the entire assembly seems to be equally contracted in the S frame with respect to the length at the start. At first sight, it might appear that the thread will not break during acceleration.
This argument, however, is incorrect as shown by Dewan and Beran, and later Bell. The distance between the spaceships does not undergo Lorentz contraction with respect to the distance at the start, because in S, it is effectively defined to remain the same, due to the equal and simultaneous acceleration of both spaceships in S. It also turns out that the rest length between the two has increased in the frames in which they are momentarily at rest (S′), because the accelerations of the spaceships are not simultaneous here due to relativity of simultaneity. The thread, on the other hand, being a physical object held together by electrostatic forces, maintains the same rest length. Thus, in frame S, it must be Lorentz contracted, which result can also be derived when the electromagnetic fields of bodies in motion are considered. So, calculations made in both frames show that the thread will break; in S′ due to the non-simultaneous acceleration and the increasing distance between the spaceships, and in S due to length contraction of the thread.
In the following, the rest length or proper length of an object is its length measured in the object's rest frame. (This length corresponds to the proper distance between two events in the special case, when these events are measured simu |
https://en.wikipedia.org/wiki/Tensor%E2%80%93vector%E2%80%93scalar%20gravity | Tensor–vector–scalar gravity (TeVeS), developed by Jacob Bekenstein in 2004, is a relativistic generalization of Mordehai Milgrom's Modified Newtonian dynamics (MOND) paradigm.
The main features of TeVeS can be summarized as follows:
As it is derived from the action principle, TeVeS respects conservation laws;
In the weak-field approximation of the spherically symmetric, static solution, TeVeS reproduces the MOND acceleration formula;
TeVeS avoids the problems of earlier attempts to generalize MOND, such as superluminal propagation;
As it is a relativistic theory it can accommodate gravitational lensing.
The theory is based on the following ingredients:
A unit vector field;
A dynamical scalar field;
A nondynamical scalar field;
A matter Lagrangian constructed using an alternate metric;
An arbitrary dimensionless function.
These components are combined into a relativistic Lagrangian density, which forms the basis of TeVeS theory.
Details
MOND is a phenomenological modification of the Newtonian acceleration law. In Newtonian gravity theory, the gravitational acceleration in the spherically symmetric, static field of a point mass at distance from the source can be written as
where is Newton's constant of gravitation. The corresponding force acting on a test mass is
To account for the anomalous rotation curves of spiral galaxies, Milgrom proposed a modification of this force law in the form
where is an arbitrary function subject to the following conditions:
In this form, MOND is not a complete theory: for instance, it violates the law of momentum conservation.
However, such conservation laws are automatically satisfied for physical theories that are derived using an action principle. This led Bekenstein to a first, nonrelativistic generalization of MOND. This theory, called AQUAL (for A QUAdratic Lagrangian) is based on the Lagrangian
where is the Newtonian gravitational potential, is the mass density, and is a dimensionless function.
In the |
https://en.wikipedia.org/wiki/Chiral%20auxiliary | In stereochemistry, a chiral auxiliary is a stereogenic group or unit that is temporarily incorporated into an organic compound in order to control the stereochemical outcome of the synthesis. The chirality present in the auxiliary can bias the stereoselectivity of one or more subsequent reactions. The auxiliary can then be typically recovered for future use.
Most biological molecules and pharmaceutical targets exist as one of two possible enantiomers; consequently, chemical syntheses of natural products and pharmaceutical agents are frequently designed to obtain the target in enantiomerically pure form. Chiral auxiliaries are one of many strategies available to synthetic chemists to selectively produce the desired stereoisomer of a given compound.
Chiral auxiliaries were introduced by Elias James Corey in 1975 with chiral 8-phenylmenthol and by Barry Trost in 1980 with chiral mandelic acid. The menthol compound is difficult to prepare and as an alternative trans-2-phenyl-1-cyclohexanol was introduced by J. K. Whitesell in 1985.
Asymmetric synthesis
Chiral auxiliaries are incorporated into synthetic routes to control the absolute configuration of stereogenic centers. David A. Evans' synthesis of the macrolide cytovaricin, considered a classic, utilizes oxazolidinone chiral auxiliaries for one asymmetric alkylation reaction and four asymmetric aldol reactions, setting the absolute stereochemistry of nine stereocenters.
A typical auxiliary-guided stereoselective transformation involves three steps: first, the auxiliary is covalently coupled to the substrate; second, the resulting compound undergoes one or more diastereoselective transformations; and finally, the auxiliary is removed under conditions that do not cause racemization of the desired products. The cost of employing stoichiometric auxiliary and the need to spend synthetic steps appending and removing the auxiliary make this approach appear inefficient. However, for many transformations, the only availabl |
https://en.wikipedia.org/wiki/Rossiter%E2%80%93McLaughlin%20effect | The Rossiter–McLaughlin effect is a spectroscopic phenomenon observed when an object moves across the face of a star.
Description
The Rossiter–McLaughlin effect is a spectroscopic phenomenon observed when either an eclipsing binary's secondary star or an extrasolar planet is seen to transit across the face of the primary or parent star.
As the main star rotates on its axis, one quadrant of its photosphere will be seen to be coming towards the viewer, and the other visible quadrant to be moving away. These motions produce blueshifts and redshifts, respectively, in the star's spectrum, usually observed as a broadening of the spectral lines. When the secondary star or planet transits the primary, it blocks part of the latter's disc, preventing some of the shifted light from reaching the observer. That causes the observed mean redshift of the primary star as a whole to vary from its normal value. As the transiting object moves across to the other side of the star's disc, the redshift anomaly will switch from being negative to being positive, or vice versa.
Retrograde Motion of Hot Jupiters
This effect has been used to show that as many as 25% of hot Jupiters are orbiting in a retrograde direction with respect to their parent stars, strongly suggesting that dynamical interactions rather than planetary migration produce these objects.
History
J. R. Holt in 1893 proposed a method to measure the stellar rotation of stars by using radial velocity measurements. He predicted that when one star of an eclipsing binary eclipsed the other, it would first cover the advancing blueshifted half and then the receding redshifted half. That motion would create a redshift of the eclipsed star's spectrum followed by a blueshift, which would thus appear as a change in the measured radial velocity in addition to that caused by the orbital motion of the eclipsed star.
The effect is named after Richard Alfred Rossiter and Dean Benjamin McLaughlin.
Further reading |
https://en.wikipedia.org/wiki/Millefleur | Millefleur, millefleurs or mille-fleur (French mille-fleurs, literally "thousand flowers") refers to a background style of many different small flowers and plants, usually shown on a green ground, as though growing in grass. It is essentially restricted to European tapestry during the late Middle Ages and early Renaissance, from about 1400 to 1550, but mainly about 1480–1520. The style had a notable revival by Morris & Co. in 19th century England, being used on original tapestry designs, as well as illustrations from his Kelmscott Press publications. The millefleur style differs from many other styles of floral decoration, such as the arabesque, in that many different sorts of individual plants are shown, and there is no regular pattern. The plants fill the field without connecting or significantly overlapping. In that it also differs from the plant and floral decoration of Gothic page borders in illuminated manuscripts.
There is also a rather different style known as millefleur in Indian carpets from about 1650 to 1800.
In the 15th century, an elaborate glass making technique was developed. See Millefiori, Murano glass and other glassmakers make pieces, particularly paper weights, that use the motif.
Tapestries
In the millefleur style the plants are dispersed across the field on a green background representing grass, to give the impression of a flowery meadow, and cover evenly the whole decorated field. At the time they were called verdures in French. They are mostly flowering plants shown as a whole, and in flower, with the coloration of the flowers of a distinct brightness compared to the usually darker background. Many are recognizable as specific species, with varying degrees of realism, but accuracy does not seem to be the point of the depiction. Neither are the flowering plants used to create perspective or depth of field. There are very often animals and sometimes human figures dispersed around the field, often rather small in relation to the plants, and |
https://en.wikipedia.org/wiki/Cocycle | In mathematics a cocycle is a closed cochain. Cocycles are used in algebraic topology to express obstructions (for example, to integrating a differential equation on a closed manifold). They are likewise used in group cohomology. In autonomous dynamical systems, cocycles are used to describe particular kinds of map, as in the Oseledets theorem.
Definition
Algebraic Topology
Let X be a CW complex and be the singular cochains with coboundary map . Then elements of are cocycles. Elements of are coboundaries. If is a cocycle, then , which means cocycles vanish on boundaries.
See also
Čech cohomology
Cocycle condition |
https://en.wikipedia.org/wiki/Civil%20flag | A civil flag is a version of the national flag that is flown by civilians on nongovernmental installations or craft. The use of civil flags was more common in the past to denote buildings or ships not crewed by the military.
In some countries, the civil flag is the same as the state flag but without the coat of arms, such as in the case of flags from Peru, Serbia and Spain. In others, it is an alteration of the war flag.
In Scandinavia, state and war flags can be double and triple-tailed variants of the Nordic Cross flag. Many countries, particularly those with a British heritage, still have distinctive civil flags (technically civil ensigns) for use at sea, many based on the Red Ensign. |
https://en.wikipedia.org/wiki/List%20of%20spherical%20symmetry%20groups | Finite spherical symmetry groups are also called point groups in three dimensions. There are five fundamental symmetry classes which have triangular fundamental domains: dihedral, cyclic, tetrahedral, octahedral, and icosahedral symmetry.
This article lists the groups by Schoenflies notation, Coxeter notation, orbifold notation, and order. John Conway uses a variation of the Schoenflies notation, based on the groups' quaternion algebraic structure, labeled by one or two upper case letters, and whole number subscripts. The group order is defined as the subscript, unless the order is doubled for symbols with a plus or minus, "±", prefix, which implies a central inversion.
Hermann–Mauguin notation (International notation) is also given. The crystallography groups, 32 in total, are a subset with element orders 2, 3, 4 and 6.
Involutional symmetry
There are four involutional groups: no symmetry (C1), reflection symmetry (Cs), 2-fold rotational symmetry (C2), and central point symmetry (Ci).
Cyclic symmetry
There are four infinite cyclic symmetry families, with n = 2 or higher. (n may be 1 as a special case as no symmetry)
Dihedral symmetry
There are three infinite dihedral symmetry families, with n = 2 or higher (n may be 1 as a special case).
Polyhedral symmetry
There are three types of polyhedral symmetry: tetrahedral symmetry, octahedral symmetry, and icosahedral symmetry, named after the triangle-faced regular polyhedra with these symmetries.
Continuous symmetries
All of the discrete point symmetries are subgroups of certain continuous symmetries. They can be classified as products of orthogonal groups O(n) or special orthogonal groups SO(n). O(1) is a single orthogonal reflection, dihedral symmetry order 2, Dih1. SO(1) is just the identity. Half turns, C2, are needed to complete.
See also
Crystallographic point group
Triangle group
List of planar symmetry groups
Point groups in two dimensions |
https://en.wikipedia.org/wiki/Information%20Hyperlinked%20over%20Proteins | Information Hyperlinked over Proteins (or iHOP) is an online text mining service that provides a gene-guided network to access PubMed abstracts. The service was established by Robert Hoffmann and Alfonso Valencia in 2004.
The concept underlying iHOP is that by using genes and proteins as hyperlinks between sentences and abstracts, the information in PubMed can be converted into one navigable resource. Navigating across interrelated sentences within this network rather than the use of conventional keyword searches allows for stepwise and controlled acquisition of information. Moreover, this literature network can be superimposed upon experimental interaction data to facilitate the simultaneous analysis of novel and existing knowledge. As of September 2014, the network presented in iHOP contains 28.4 million sentences and 110,000 genes from over 2,700 organisms, including the model organisms Homo sapiens, Mus musculus, Drosophila melanogaster, Caenorhabditis elegans, Danio rerio, Arabidopsis thaliana, Saccharomyces cerevisiae and Escherichia coli.
The iHOP system has shown that by navigating from gene to gene, distant medical and biological concepts may be connected by only a small number of genes; the shortest path between two genes has been shown to involve on average four intermediary genes.
The iHOP system architecture consists of two separate parts: the 'iHOP factory' and the web application. The iHOP factory manages the PubMed source data (text and gene data) and organises it within a PostgreSQL relational database. The iHOP factory also produces the relevant XML output for display by the web application.
iHOP is free to use and is licensed under a Creative Commons BY-ND license. |
https://en.wikipedia.org/wiki/XLink%20Kai | XLink Kai is a program developed by Team XLink allowing for online play of video games with support for LAN multiplayer modes. It enables players on the GameCube, Nintendo Switch, PlayStation 2, PlayStation 3, PlayStation 4, PlayStation Portable, PlayStation Vita / PlayStation TV, Xbox, Xbox 360, and Xbox One to play games across the Internet using a network configuration that simulates a local area network (LAN). It notably also allows original Xbox games to be played online again following the Xbox Live shutdown on 21 April 2010 (similar to that of Save Nintendo Wi-Fi for the Wii) and certain GameSpy titles such as Saints Row 2 to be played online after the GameSpy network shutdown on 31 May 2014.
Summary
The purpose of the software is to allow consoles to network with each other over the internet via the consoles' "local network play" capabilities. XLink Kai acts as tunneling software, installed to a compatible Microsoft Windows, macOS, or Linux computer on the same network as the console. Upon the console initiating a game's "network play" feature, the console's requests are routed to the computer. XLink, listening for these requests, allows other consoles to be found over the internet during this search, making it appear to the player's console that these other consoles are simply connected to the local network.
For modified ("modded") Xbox consoles, much of the functionality can be provided directly within the Xbox Media Center (XBMC for Xbox) GUI. The Kai client is still required to be running on a computer on the user's network, but players can control connections directly through the console. It is also possible to run the Kai client on other Linux-based devices, such as Raspberry Pi or NAS devices.
Usage
Users log onto XLink's servers using an XTag username, similar to a "Gamertag" for Xbox Live. XLink has "Arenas" for each compatible System Link game, with more popular games such as Halo 2 and SOCOM II having sub-arenas based on regions within them |
https://en.wikipedia.org/wiki/Pohlmeyer%20charge | In theoretical physics Pohlmeyer charge, named for Klaus Pohlmeyer, is a conserved charge invariant under the Virasoro algebra or its generalization. It can be obtained by expanding the holonomies (generating functions)
with respect to the constant matrices T. The gauge field is defined as a combination of and its conjugate.
According to the logic of loop quantum gravity and algebraic quantum field theory, these charges are the right physical quantities that should be used for quantization. This logic is however incompatible with the standard and well-established methods of quantum field theory based on Fock space and perturbation theory.
Theoretical physics
Quantum field theory
Conformal field theory |
https://en.wikipedia.org/wiki/Internal%20ribosome%20entry%20site | An internal ribosome entry site, abbreviated IRES, is an RNA element that allows for translation initiation in a cap-independent manner, as part of the greater process of protein synthesis. In eukaryotic translation, initiation typically occurs at the 5' end of mRNA molecules, since 5' cap recognition is required for the assembly of the initiation complex. The location for IRES elements is often in the 5'UTR, but can also occur elsewhere in mRNAs.
History
IRES sequences were first discovered in 1988 in the poliovirus (PV) and encephalomyocarditis virus (EMCV) RNA genomes in the labs of Nahum Sonenberg and Eckard Wimmer, respectively. They are described as distinct regions of RNA molecules that are able to recruit the eukaryotic ribosome to the mRNA. This process is also known as cap-independent translation. It has been shown that IRES elements have a distinct secondary or even tertiary structure, but similar structural features at the levels of either primary or secondary structure that are common to all IRES segments have not been reported to date.
In recent years it has become common for molecular biologists to insert IRES sequences into their vectors to allow for expression of two genes from a single vector—for example, a transgene and a fluorescent reporter molecule. The first gene is initiated at the normal 5' cap, and the second gene is initiated at the IRES.
Location
IRESs are commonly located in the 5'UTR of RNA viruses and allow translation of the RNAs in a cap-independent manner. However, mRNAs of viruses from Dicistroviridae family possess two open reading frames (ORFs), and translation of each is directed by two distinct IRESs. It has also been suggested that some mammalian cellular mRNAs also have IRESs. These cellular IRES elements are thought to be located in eukaryotic mRNAs encoding genes involved in stress survival, and other processes critical to survival. As of September 2009, there are 60 animal and 8 plant viruses reported to contain IRES e |
https://en.wikipedia.org/wiki/Bird%27s-eye%20view | A bird's-eye view is an elevated view of an object or location from a very steep viewing angle, creating a perspective as if the observer were a bird in flight looking downwards. Bird's-eye views can be an aerial photograph, but also a drawing, and are often used in the making of blueprints, floor plans and maps.
Before crewed flight was common, the term "bird's eye" was used to distinguish views drawn from direct observation at high vantage locations (e.g. a mountain or tower), from those constructed from an imagined bird's perspectives. Bird's eye views as a genre have existed since classical times. They were significantly popular in the mid-to-late 19th century in the United States and Europe as photographic prints.
Terminology
The terms aerial view and aerial viewpoint are also sometimes used synonymous with bird's-eye view. The term aerial view can refer to any view from a great height, even at a wide angle, as for example when looking sideways from an airplane window or from a mountain top. Overhead view is fairly synonymous with bird's-eye view but tends to imply a vantage point of a lesser height than the latter term. For example, in computer and video games, an "overhead view" of a character or situation often places the vantage point only a few feet (a meter or two) above human height. See top-down perspective.
Recent technological and networking developments have made satellite images more accessible. Microsoft Bing Maps offers direct overhead satellite photos of the entire planet but also offers a feature named Bird's eye view in some locations. The Bird's Eye photos are angled at 40 degrees rather than being straight down. Satellite imaging programs and photos have been described as offering a viewer the opportunity to "fly over" and observe the world from this specific angle.
In filmmaking and video production, a bird's-eye shot refers to a shot looking directly down on the subject. The perspective is very foreshortened, making the subject appear |
https://en.wikipedia.org/wiki/Pinnacle%20Foods | Pinnacle Foods, Inc., is a packaged foods company headquartered in Parsippany, New Jersey, that specializes in shelf-stable and frozen foods. The company became a subsidiary of Conagra Brands on October 26, 2018.
History
The company was founded in 1998 as "Vlasic Foods International", acquiring the Swanson TV dinners, Open Pit, and Vlasic Pickles brands from the Campbell Soup Company. Between 2001 and 2007 the spinoff of former Campbell Soup Company branded food lines was owned by the Metropoulos Group which named it Pinnacle Foods.
In 2007, Pinnacle Foods was acquired by the Blackstone Group, a New York City-based private equity firm.
In 2013, Pinnacle Foods' Parsippany office was named Inc. Magazine's "World's Coolest Office." That year, Pinnacle Foods had its IPO on the New York Stock Exchange, raising approximately $580 million for its owners, the private equity Blackstone Group. Shares began trading under the ticker symbol PF on April 4 at the upper range of its offering, $20 per share, thereby valuing Pinnacle Foods with a market capitalization of $2.3 billion.
In May 2014, Hillshire Brands announced it was buying Pinnacle Foods for $4.23 billion in a cash and stock deal. Hillshire Brands' portfolio includes Jimmy Dean, Ball Park, and Sara Lee. But on June 30, 2014, it was announced that Pinnacle Foods had scrapped its sale to Hillshire Brands, which would allow Hillshire Brands to be acquired by Tyson Foods. Pinnacle was to receive a $163 million payment as part of the breakup from Hillshire, and also receive an expected $25 million in one-time costs connected to the scotched sale.
In March 2016, it was announced that CEO Robert Gamgort would be leaving Pinnacle Foods to be the new CEO of Keurig Green Mountain. Mark A. Clouse, formerly of Mondelēz, succeeded Gamgort as CEO of the company.
In June 2018, Conagra announced it would acquire Pinnacle Foods for $8.1 billion. The sale was completed on October 26, 2018 and the company was delisted in the NYSE.
|
https://en.wikipedia.org/wiki/Theomatics | Theomatics is a numerological study of the Hebrew/Aramaic and Greek text of the Christian Bible (see also Biblical numerology), based upon gematria and isopsephia, by which its proponents claim to show the direct intervention of God in the writing of Christian scripture.
Etymology
The term "theomatics" was coined by Del Washburn in 1976 as a combination of "Θεός" ("God") and "mathematics". Washburn wrote three books about theomatics and created a website espousing the hypothesis.
Controversy
An analysis and criticism of theomatics has been published by
Tim Hayes, previously under the pseudonym "A. B. Leever".
A German statistician, Kurt Fettelschoss, published an analysis that claims that "The observed quantity of theomatic hits is significantly not random". A response to the findings was posted by Tim Hayes. A further statistical analysis in defense, of Mr. Hayes response, was provided by Mr. Fettelschoss. [6]
An analysis by Russell Glasser, entitled "Theomatics Debunked", shows the same phenomenon in a secular text.
Washburn's website has a page entitled "Scientific Proof" which discusses and responds to potential arguments against theomatics. |
https://en.wikipedia.org/wiki/Lottery%20mathematics | Lottery mathematics is used to calculate probabilities of winning or losing a lottery game. It is based primarily on combinatorics, particularly the twelvefold way and combinations without replacement.
Choosing 6 from 49
In a typical 6/49 game, each player chooses six distinct numbers from a range of 1-49. If the six numbers on a ticket match the numbers drawn by the lottery, the ticket holder is a jackpot winner—regardless of the order of the numbers. The probability of this happening is 1 in 13,983,816.
The chance of winning can be demonstrated as follows: The first number drawn has a 1 in 49 chance of matching. When the draw comes to the second number, there are now only 48 balls left in the bag, because the balls are drawn without replacement. So there is now a 1 in 48 chance of predicting this number.
Thus for each of the 49 ways of choosing the first number there are 48 different ways of choosing the second. This means that the probability of correctly predicting 2 numbers drawn from 49 in the correct order is calculated as 1 in 49 × 48. On drawing the third number there are only 47 ways of choosing the number; but we could have arrived at this point in any of 49 × 48 ways, so the chances of correctly predicting 3 numbers drawn from 49, again in the correct order, is 1 in 49 × 48 × 47. This continues until the sixth number has been drawn, giving the final calculation, 49 × 48 × 47 × 46 × 45 × 44, which can also be written as or 49 factorial divided by 43 factorial or FACT(49)/FACT(43) or simply PERM(49,6) .
608281864034267560872252163321295376887552831379210240000000000 / 60415263063373835637355132068513997507264512000000000 = 10068347520
This works out to 10,068,347,520, which is much bigger than the ~14 million stated above.
Perm(49,6)=10068347520 and 49 nPr 6 =10068347520.
However, the order of the 6 numbers is not significant for the payout. That is, if a ticket has the numbers 1, 2, 3, 4, 5, and 6, it wins as long as all the numbers 1 through 6 |
https://en.wikipedia.org/wiki/Interleave%20sequence | In mathematics, an interleave sequence is obtained by merging two sequences via an in shuffle.
Let be a set, and let and , be two sequences in The interleave sequence is defined to be the sequence . Formally, it is the sequence given by
Properties
The interleave sequence is convergent if and only if the sequences and are convergent and have the same limit.
Consider two real numbers a and b greater than zero and smaller than 1. One can interleave the sequences of digits of a and b, which will determine a third number c, also greater than zero and smaller than 1. In this way one obtains an injection from the square to the interval (0, 1). Different radixes give rise to different injections; the one for the binary numbers is called the Z-order curve or Morton code. |
https://en.wikipedia.org/wiki/Type%20generalization | Type generalization is a technique commonly used in refactoring. The idea is to draw on the benefits of object-orientation and make more-generalized types, thus enabling more code sharing, leading to better maintainability as there is less code to write. Too-general code can, however, become completely useless, leading to spaghetti code doing effectively nothing.
Type generalization refers to making more general or more abstract some subset of the traits of a specific type. A superclass has wider use than a specific subclass, and so is more 'general'.
An example of generalizing a type would be moving a method from a child to a parent class for common use by all the parent class' children, not just the original child.
Another example, in the Java programming language, would be access to an object via an interface which isn't tied into a specific implementation of that interface. |
https://en.wikipedia.org/wiki/Stolz%E2%80%93Ces%C3%A0ro%20theorem | In mathematics, the Stolz–Cesàro theorem is a criterion for proving the convergence of a sequence. The theorem is named after mathematicians Otto Stolz and Ernesto Cesàro, who stated and proved it for the first time.
The Stolz–Cesàro theorem can be viewed as a generalization of the Cesàro mean, but also as a l'Hôpital's rule for sequences.
Statement of the theorem for the case
Let and be two sequences of real numbers. Assume that is a strictly monotone and divergent sequence (i.e. strictly increasing and approaching , or strictly decreasing and approaching ) and the following limit exists:
Then, the limit
Statement of the theorem for the case
Let and be two sequences of real numbers. Assume now that and while is strictly decreasing. If
then
Proofs
Proof of the theorem for the case
Case 1: suppose strictly increasing and divergent to , and . By hypothesis, we have that for all there exists such that
which is to say
Since is strictly increasing, , and the following holds
.
Next we notice that
thus, by applying the above inequality to each of the terms in the square brackets, we obtain
Now, since as , there is an such that for all , and we can divide the two inequalities by for all
The two sequences (which are only defined for as there could be an such that )
are infinitesimal since and the numerator is a constant number, hence for all there exists , such that
therefore
which concludes the proof. The case with strictly decreasing and divergent to , and is similar.
Case 2: we assume strictly increasing and divergent to , and . Proceeding as before, for all there exists such that for all
Again, by applying the above inequality to each of the terms inside the square brackets we obtain
and
The sequence defined by
is infinitesimal, thus
combining this inequality with the previous one we conclude
The proofs of the other cases with strictly increasing or decreasing and approaching or respectively and all pr |
https://en.wikipedia.org/wiki/Square%20lattice | In mathematics, the square lattice is a type of lattice in a two-dimensional Euclidean space. It is the two-dimensional version of the integer lattice, denoted as . It is one of the five types of two-dimensional lattices as classified by their symmetry groups; its symmetry group in IUC notation as , Coxeter notation as , and orbifold notation as .
Two orientations of an image of the lattice are by far the most common. They can conveniently be referred to as the upright square lattice and diagonal square lattice; the latter is also called the centered square lattice. They differ by an angle of 45°. This is related to the fact that a square lattice can be partitioned into two square sub-lattices, as is evident in the colouring of a checkerboard.
Symmetry
The square lattice's symmetry category is wallpaper group . A pattern with this lattice of translational symmetry cannot have more, but may have less symmetry than the lattice itself.
An upright square lattice can be viewed as a diagonal square lattice with a mesh size that is √2 times as large, with the centers of the squares added. Correspondingly, after adding the centers of the squares of an upright square lattice one obtains a diagonal square lattice with a mesh size that is √2 times as small as that of the original lattice.
A pattern with 4-fold rotational symmetry has a square lattice of 4-fold rotocenters that is a factor √2 finer and diagonally oriented relative to the lattice of translational symmetry.
With respect to reflection axes there are three possibilities:
None. This is wallpaper group .
In four directions. This is wallpaper group .
In two perpendicular directions. This is wallpaper group . The points of intersection of the reflexion axes form a square grid which is as fine as, and oriented the same as, the square lattice of 4-fold rotocenters, with these rotocenters at the centers of the squares formed by the reflection axes.
Crystal classes
The square lattice class names, Schönflies notation, |
https://en.wikipedia.org/wiki/Standard%20algorithms | In elementary arithmetic, a standard algorithm or method is a specific method of computation which is conventionally taught for solving particular mathematical problems. These methods vary somewhat by nation and time, but generally include exchanging, regrouping, long division, and long multiplication using a standard notation, and standard formulas for average, area, and volume. Similar methods also exist for procedures such as square root and even more sophisticated functions, but have fallen out of the general mathematics curriculum in favor of calculators (or tables and slide rules before them).
The concepts of reform mathematics which the NCTM introduced in 1989 favors an alternative approach. It proposes a deeper understanding of the underlying theory instead of memorization of specific methods will allow students to develop individual methods which solve the same problems. Students' alternative algorithms are often just as correct, efficient, and generalizable as the standard algorithms, and maintain emphasis on the meaning of the quantities involved, especially as relates to place values (something that is usually lost in the memorization of standard algorithms). The development of sophisticated calculators has made manual calculation less important (see the note on square roots, above) and cursory teaching of traditional methods has created failure among many students. Greater achievement among all types of students is among the primary goals of mathematics education put forth by NCTM. Some researchers such as Constance Kamii have suggested that elementary arithmetic, as traditionally taught, is not appropriate in elementary school. Many first editions of textbooks written to the original 1989 standard such as TERC deliberately discouraged teaching of any particular method, instead devoting class and homework time to the solving of nontrivial problems, which stimulate students to develop their own methods of calculation, rooted in number sense and place v |
https://en.wikipedia.org/wiki/Internet%20transit | Internet transit is the service of allowing network traffic to cross or "transit" a computer network, usually used to connect a smaller Internet service provider (ISP) to the larger Internet. Technically, it consists of two bundled services:
The advertisement of customer routes to other ISPs, thereby soliciting inbound traffic toward the customer from them
The advertisement of other ISPs' routes (usually but not necessarily in the form of a default route or a full set of routes to all of the destinations on the Internet) to the ISP's customer, thereby soliciting outbound traffic from the customer towards these networks.
In the 1970s and early 1980s-era Internet, the assumption was made that all networks would provide full transit for one another. In the modern private-sector Internet, two forms of interconnect agreements exist between Internet networks: transit, and peering. Transit is distinct from peering, in which only traffic between the two ISPs and their downstream customers is exchanged and neither ISP can see upstream routes over the peering connection. A transit free network uses only peering; a network that uses only unpaid peering and connects to the whole Internet is considered a Tier 1 network. In the 1990s, the network access point concept provided one form of transit.
Pricing for the internet transit varies at different times and geographical locations. The transit service is typically priced per megabit per second per month, and customers are often required to commit to a minimum volume of bandwidth, and usually to a minimum term of service as well, usually using a 95e percentile burstable billing scheme. Some transit agreements provide "service-level agreements" which purport to offer money-back guarantees of performance between the customer's Internet connection and specific points on the Internet, typically major Internet exchange points within a continental geography such as North America. These service level agreements still provide only bes |
https://en.wikipedia.org/wiki/McDonald%20criteria | The McDonald criteria are diagnostic criteria for multiple sclerosis (MS). These criteria are named after neurologist W. Ian McDonald who directed an international panel in association with the National Multiple Sclerosis Society (NMSS) of America and recommended revised diagnostic criteria for MS in April 2001. These new criteria intended to replace the Poser criteria and the older Schumacher criteria. They have undergone revisions in 2005, 2010 and 2017.
They maintain the Poser requirement to demonstrate "dissemination of lesions in space and time" (DIS and DIT) but they discourage the previously used Poser terms such as "clinically definite" and "probable MS", and propose as diagnostic either "MS", "possible MS", or "not MS".
The McDonald criteria maintained a scheme for diagnosing MS based solely on clinical grounds but also proposed for the first time that when clinical evidence is lacking, magnetic resonance imaging (MRI) findings can serve as surrogates for dissemination in space (DIS) and/or time (DIT) to diagnose MS. The criteria try to prove the existence of demyelinating lesions, by image or by their effects, showing that they occur in different areas of the nervous system (DIS) and that they accumulate over time (DIT). The McDonald criteria facilitate the diagnosis of MS in patients who present with their first demyelinating attack and significantly increase the sensitivity for diagnosing MS without compromising the specificity.
The McDonald criteria for the diagnosis of multiple sclerosis were revised first in 2005 to clarify exactly what is meant by an "attack", "dissemination" and a "positive MRI", etc. Later they were revised again in 2017.
McDonald criteria are the standard clinical case definition for MS and the 2010 version is regarded as the gold standard test for MS diagnosis.
Diagnostic Criteria
They discourage the previously used terms such as "clinically definite" and "probable MS", and propose as diagnostic variants like "MS", "possibl |
https://en.wikipedia.org/wiki/Energy%E2%80%93momentum%20relation | In physics, the energy–momentum relation, or relativistic dispersion relation, is the relativistic equation relating total energy (which is also called relativistic energy) to invariant mass (which is also called rest mass) and momentum. It is the extension of mass–energy equivalence for bodies or systems with non-zero momentum. It can be written as the following equation:
This equation holds for a body or system, such as one or more particles, with total energy , invariant mass , and momentum of magnitude ; the constant is the speed of light. It assumes the special relativity case of flat spacetime and that the particles are free. Total energy is the sum of rest energy and kinetic energy, while invariant mass is mass measured in a center-of-momentum frame.
For bodies or systems with zero momentum, it simplifies to the mass–energy equation , where total energy in this case is equal to rest energy (also written as ).
The Dirac sea model, which was used to predict the existence of antimatter, is closely related to the energy–momentum relation.
Connection to
The energy–momentum relation is consistent with the familiar mass–energy relation in both its interpretations: relates total energy to the (total) relativistic mass (alternatively denoted or ), while relates rest energy to (invariant) rest mass .
Unlike either of those equations, the energy–momentum equation () relates the total energy to the rest mass . All three equations hold true simultaneously.
Special cases
If the body is a massless particle (), then () reduces to . For photons, this is the relation, discovered in 19th century classical electromagnetism, between radiant momentum (causing radiation pressure) and radiant energy.
If the body's speed is much less than , then () reduces to ; that is, the body's total energy is simply its classical kinetic energy () plus its rest energy.
If the body is at rest (), i.e. in its center-of-momentum frame (), we have and ; thus the energy–mo |
https://en.wikipedia.org/wiki/Optimum%20programming | In the history of computing, optimum programming, or optimum coding is the practice of arranging a computer program's instructions in memory so as to minimize the time the machine spends waiting for instructions. It is of historical interest mainly due to the design of many early digital computers.
Most early computers used some form of serial memory, primarily delay-line memory or magnetic drums. Unlike the random-access memory of modern computers, words in serial memory are made available one at a time; the time required to access a particular word depends on the "distance" between it and the word currently being read. If a given delay line held n words, the average time to read a word would be n/2 word times. Without optimum coding, such a machine would spend most of its time idly waiting for instructions and data.
To circumvent this problem, many machines, particularly Alan Turing's ACE and its descendants, included a field specifying the address of the next instruction to be executed in their instruction format. A programmer employing optimum coding would look up the time needed to perform the current instruction, calculate how far the memory system would move in that time, and then place the next instruction for the program at that location. Thus when the current instruction completed and the computer looked for the next one as specified in the instruction, that memory location would just be arriving and would be able to be read in immediately. For example, if a programmer had just coded an ADD instruction at address 400, and the ADD instruction required 4 word-times to execute, the programmer would set the "next address" field of the instruction to 404, and would place the next instruction there.
In the United States, optimum coding was most commonly employed on the IBM 650 and the Bendix G-15. Both machines had optimizing assemblers (SOAP for the IBM, POGO for Bendix) that could automate this task.
See also
Mel Kaye, who authored one particularly clever |
https://en.wikipedia.org/wiki/Isomalt | Isomalt is a sugar substitute, a mixture of the two disaccharide alcohols 1,6-GPS and 1,1-GPM. It is used primarily for its sugar-like physical properties. It has little to no impact on blood sugar levels, and does not stimulate the release of insulin. It also does not promote tooth decay and is considered to be tooth-friendly. Its energy value is 2 kcal per gram, half that of sugars. It is less sweet than sugar, but can be blended with high-intensity sweeteners such as sucralose to create a mixture with the same sweetness as sucrose (‘sugar’).
Like most sugar alcohols (including the chemically similar maltitol), isomalt carries a risk of intestinal distress when consumed in large quantities (above about 20–30 g (1 oz) per day). Isomalt may prove upsetting to the intestinal tract because it is incompletely absorbed in the small intestine, and when polyols pass into the large intestine, they can cause osmotically-induced diarrhea and stimulate the gut flora, causing flatulence. As with dietary fibers, regular consumption of isomalt can lead to desensitization, decreasing the risk of intestinal upset.
Isomalt has been approved for use in the United States since 1990. It is also permitted for use in Australia, New Zealand, Canada, Mexico, Iran, the European Union, and other countries.
Composition and structure
Isomalt is an equimolar mixture of two diastereomeric disaccharides: 1-O-α-D-glucopyranosido-D-mannitol (1,1-GPM) and 6-O-α-D-glucopyranosido-D-sorbitol (1,6-GPS). Each of these is composed of two sugars: glucose and mannitol in the case of 1,1-GPM and glucose and sorbitol (also known as glucitol) in the case of 1,6-GPS.
Complete hydrolysis of isomalt yields glucose (50%), sorbitol (25%), and mannitol (25%).
Isomalt is an odorless, white, crystalline substance containing about 5% water of crystallisation. Isomalt has a minimal cooling effect (positive heat of solution), lower than many other sugar alcohols, in particular, xylitol and erythritol.
Manufactu |
https://en.wikipedia.org/wiki/Spatial%20variability | Spatial variability occurs when a quantity that is measured at different spatial locations exhibits values that differ across the locations. Spatial variability can be assessed using spatial descriptive statistics such as the range.
Let us suppose that the Rev' z(x) is perfectly known at any point x within the field under study. Then the uncertainty about z(x) is reduced to zero, whereas its spatial variability still exists. Uncertainty is closely related to the amount of spatial variability, but it is also strongly dependent upon sampling.
Geostatistical analyses have been strictly performed to study the spatial variability of pesticide sorption and degradation in the field. Webster and Oliver provided a description of geostatistical techniques. Describing uncertainty using geostatistics is not an activity exempt from uncertainty itself as variogram uncertainty may be large and spatial interpolation may be undertaken using different techniques. |
https://en.wikipedia.org/wiki/Compressor%20map | A compressor map is a chart which shows the performance of a turbomachinery compressor. This type of compressor is used in gas turbine engines, for supercharging reciprocating engines and for industrial processes, where it is known as a dynamic compressor. A map is created from compressor rig test results or predicted by a special computer program. Alternatively the map of a similar compressor can be suitably scaled. This article is an overview of compressor maps and their different applications and also has detailed explanations of maps for a fan and intermediate and high-pressure compressors from a three-shaft aero-engine as specific examples.
Compressor maps are an integral part of predicting the performance of gas turbine and turbocharged engines, both at design and off-design conditions. They also serve a critical purpose in selecting the correct compressors for industrial processes.
Fans and turbines also have operating maps, although the latter are significantly different in appearance to that of compressors.
Compressor design
A compressor map shows the operating range of a compressor and how well it works within its operating range. Two fundamental requirements for the gas flowing through a compressor explain why it works best at a design condition and not so well at other conditions, known as off-design. First, the exit area has to be smaller than the inlet area because the compressed gas has a higher density. The exit area is sized to pass the specific volume at the design condition. Second, all the rotor and stator blades in an axial compressor, and impeller inducer and diffuser vanes in a centrifugal compressor, are angled to meet approaching air head-on at the design condition to minimize incidence losses. Incidence losses reduce the efficiency of compression. Satisfactory operation of the compressor relies on controlling the angle at which the gas approaches rotating and stationary blades to within an acceptable range. Deviating from the optimum fir |
https://en.wikipedia.org/wiki/Heath%E2%80%93Jarrow%E2%80%93Morton%20framework | The Heath–Jarrow–Morton (HJM) framework is a general framework to model the evolution of interest rate curves – instantaneous forward rate curves in particular (as opposed to simple forward rates). When the volatility and drift of the instantaneous forward rate are assumed to be deterministic, this is known as the Gaussian Heath–Jarrow–Morton (HJM) model of forward rates. For direct modeling of simple forward rates the Brace–Gatarek–Musiela model represents an example.
The HJM framework originates from the work of David Heath, Robert A. Jarrow, and Andrew Morton in the late 1980s, especially Bond pricing and the term structure of interest rates: a new methodology (1987) – working paper, Cornell University, and Bond pricing and the term structure of interest rates: a new methodology (1989) – working paper (revised ed.), Cornell University. It has its critics, however, with Paul Wilmott describing it as "...actually just a big rug for [mistakes] to be swept under".
Framework
The key to these techniques is the recognition that the drifts of the no-arbitrage evolution of certain variables can be expressed as functions of their volatilities and the correlations among themselves. In other words, no drift estimation is needed.
Models developed according to the HJM framework are different from the so-called short-rate models in the sense that HJM-type models capture the full dynamics of the entire forward rate curve, while the short-rate models only capture the dynamics of a point on the curve (the short rate).
However, models developed according to the general HJM framework are often non-Markovian and can even have infinite dimensions. A number of researchers have made great contributions to tackle this problem. They show that if the volatility structure of the forward rates satisfy certain conditions, then an HJM model can be expressed entirely by a finite state Markovian system, making it computationally feasible. Examples include a one-factor, two state model (O. Ch |
https://en.wikipedia.org/wiki/Stuart%20Parkin | Stuart Stephen Papworth Parkin (born 9 December 1955) is an experimental physicist, director at the Max Planck Institute of Microstructure Physics in Halle and an Alexander von Humboldt Professor at the Institute of Physics of the Martin-Luther-University Halle-Wittenberg.
He is a pioneer in the science and application of spintronic materials, and has made discoveries into the behaviour of thin-film magnetic structures that were critical in enabling recent increases in the data density and capacity of computer hard-disk drives. For these discoveries, he was awarded the 2014 Millennium Technology Prize.
Before his current position, Parkin was an IBM Fellow and manager of the magnetoelectronics group at the IBM Almaden Research Center in San Jose, California. He was also a consulting professor in the department of applied physics at Stanford University and director of the IBM-Stanford Spintronic Science and Applications Center, which was formed in 2004.
Education and early life
A native of Watford, England, Parkin received his B.A. (1977) and was elected a research fellow (1979) at Trinity College, Cambridge, England, and was awarded his PhD (1980) at the Cavendish Laboratory, also in Cambridge. He joined IBM in 1982 as a World Trade Post-doctoral Fellow, becoming a permanent member of the staff the following year. In 1999 he was named an IBM Fellow, IBM's highest technical honour.
Research and career
In 2007 Parkin was named a distinguished visiting professor at the National University of Singapore, a visiting chair professor at the National Taiwan University, and an honorary visiting professor at University College London, The United Kingdom. In 2008, he was elected to the National Academy of Sciences. The Materials Research Network Dresden granted him the Dresden Barkhausen Award in 2009. Parkin has been awarded honorary doctorates by the University of Aachen, Germany and the Eindhoven University of Technology, The Netherlands.
In 1989 Stuart Parkin discovere |
https://en.wikipedia.org/wiki/Temperateness%20%28virology%29 | In virology, temperate refers to the ability of some bacteriophages (notably coliphage λ) to display a lysogenic life cycle. Many (but not all) temperate phages can integrate their genomes into their host bacterium's chromosome, together becoming a lysogen as the phage genome becomes a prophage. A temperate phage is also able to undergo a productive, typically lytic life cycle, where the prophage is expressed, replicates the phage genome, and produces phage progeny, which then leave the bacterium. With phage the term virulent is often used as an antonym to temperate, but more strictly a virulent phage is one that has lost its ability to display lysogeny through mutation rather than a phage lineage with no genetic potential to ever display lysogeny (which more properly would be described as an obligately lytic phage).
Induction
At some point, temperate bacteriophages switch from the lysogenic life cycle to the lytic life cycle. This conversion may happen spontaneously, although at very low frequencies (λ displays spontaneous conversion of 10−8 to 10−5 per cell). In the majority of observed switch events, stressors - such as the cell's SOS response (due to DNA damage) or a change in nutrients - induces the switch.
Notes
Virology
Bacteriophages |
https://en.wikipedia.org/wiki/Front%20end%20of%20line | The front-end-of-line (FEOL) is the first portion of IC fabrication where the individual components (transistors, capacitors, resistors, etc.) are patterned in the semiconductor.
FEOL generally covers everything up to (but not including) the deposition of metal interconnect layers.
For the CMOS process, FEOL contains all fabrication steps needed to form isolated CMOS elements:
Selecting the type of wafer to be used; Chemical-mechanical planarization and cleaning of the wafer.
Shallow trench isolation (STI) (or LOCOS in early processes, with feature size > 0.25 μm)
Well formation
Gate module formation
Source and drain module formation
See also
Back end of line
Integrated circuit |
https://en.wikipedia.org/wiki/Back%20end%20of%20line | The back end of line (BEOL) is the second portion of IC fabrication where the individual devices (transistors, capacitors, resistors, etc.) get interconnected with wiring on the wafer, the metalization layer. Common metals are copper and aluminum.
BEOL generally begins when the first layer of metal is deposited on the wafer. BEOL includes contacts, insulating layers (dielectrics), metal levels, and bonding sites for chip-to-package connections.
After the last FEOL step, there is a wafer with isolated transistors (without any wires). In BEOL part of fabrication stage contacts (pads), interconnect wires, vias and dielectric structures are formed. For modern IC process, more than 10 metal layers can be added in the BEOL.
Steps of the BEOL:
Silicidation of source and drain regions and the polysilicon region.
Adding a dielectric (first, lower layer is pre-metal dielectric (PMD) – to isolate metal from silicon and polysilicon), CMP processing it
Make holes in PMD, make a contacts in them.
Add metal layer 1
Add a second dielectric, called the inter-metal dielectric (IMD)
Make vias through dielectric to connect lower metal with higher metal. Vias filled by Metal CVD process.
Repeat steps 4–6 to get all metal layers.
Add final passivation layer to protect the microchip
Before 1998, practically all chips used aluminium for the metal interconnection layers.
The four metals with the highest electrical conductivity are silver with the highest conductivity, then copper, then gold, then aluminium.
After BEOL there is a "back-end process" (also called post-fab), which is done not in the cleanroom, often by a different company.
It includes wafer test, wafer backgrinding, die separation, die tests, IC packaging and final test.
See also
Front end of line
Integrated circuit
Phosphosilicate glass |
https://en.wikipedia.org/wiki/Icosahedral%20symmetry | In mathematics, and especially in geometry, an object has icosahedral symmetry if it has the same symmetries as a regular icosahedron. Examples of other polyhedra with icosahedral symmetry include the regular dodecahedron (the dual of the icosahedron) and the rhombic triacontahedron.
Every polyhedron with icosahedral symmetry has 60 rotational (or orientation-preserving) symmetries and 60 orientation-reversing symmetries (that combine a rotation and a reflection), for a total symmetry order of 120. The full symmetry group is the Coxeter group of type . It may be represented by Coxeter notation and Coxeter diagram . The set of rotational symmetries forms a subgroup that is isomorphic to the alternating group on 5 letters.
Description
Icosahedral symmetry is a mathematical property of objects indicating that an object has the same symmetries as a regular icosahedron.
As point group
Apart from the two infinite series of prismatic and antiprismatic symmetry, rotational icosahedral symmetry or chiral icosahedral symmetry of chiral objects and full icosahedral symmetry or achiral icosahedral symmetry are the discrete point symmetries (or equivalently, symmetries on the sphere) with the largest symmetry groups.
Icosahedral symmetry is not compatible with translational symmetry, so there are no associated crystallographic point groups or space groups.
Presentations corresponding to the above are:
These correspond to the icosahedral groups (rotational and full) being the (2,3,5) triangle groups.
The first presentation was given by William Rowan Hamilton in 1856, in his paper on icosian calculus.
Note that other presentations are possible, for instance as an alternating group (for I).
Visualizations
The full symmetry group is the Coxeter group of type . It may be represented by Coxeter notation and Coxeter diagram . The set of rotational symmetries forms a subgroup that is isomorphic to the alternating group on 5 letters.
Group structure
Every polyhedron |
https://en.wikipedia.org/wiki/Department%20of%20Aerospace%20Science%20and%20Technology | The Brazilian Department of Science and Aerospace Technology (; DCTA) is the national military research center for aviation and space flight. It is subordinated to the Brazilian Air Force (FAB).
It coordinates all technical and scientific activities related to the aerospace sector in which there are interests by the Ministry of Defense. It was established in 1953. It currently employs several thousand civilian and military personnel.
Institutes
The DCTA has four institutes within its campus.
Aeronautics and Space Institute (IAE)
Aeronautics and Space Institute (). It develops projects in the aeronautical, airspace and defense sectors, co-responsible for the execution of the Brazilian Space Mission.
Aeronautics Institute of Technology (ITA)
Aeronautics Institute of Technology () is one of the main educational colleges of the Brazilian Air Force.
Institute for Advanced Studies (IEAv)
Institute for Advanced Studies (). Responsible for the development of pure and applied sciences: photonics, nuclear energy, applied physics, remote sensor systems and decision support systems. In 2006, the IEAv inaugurated the T3 Hypersonic wind tunnel, the largest in Latin America.
Industrial Promotion and Coordination Institute (IFI)
Industrial Promotion and Coordination Institute (). It provides military aeronautical certification and aerospace equipment approval, acting as an interface between the institutes and the industry. Until 2006, it carried out the civil aircraft certification activities, today under the National Civil Aviation Agency responsibilities.
Flight Testing and Research Institute (IPEV)
Flight Testing and Research Institute (). This institute is responsible for the instruction and fulfillment of flight testing campaigns (founded 1953). IPEV has a dedicated Air Force Squadron, based at CTA using the A-29A Super Tucano, C-95BM & CM Bandeirante, and the C-97 Brasília.
Museum
The DCTA is also responsible managing for the Brazilian Aerospace Memorial (Memorial A |
https://en.wikipedia.org/wiki/Longitudinal%20mode | A longitudinal mode of a resonant cavity is a particular standing wave pattern formed by waves confined in the cavity. The longitudinal modes correspond to the wavelengths of the wave which are reinforced by constructive interference after many reflections from the cavity's reflecting surfaces. All other wavelengths are suppressed by destructive interference.
A longitudinal mode pattern has its nodes located axially along the length of the cavity. Transverse modes, with nodes located perpendicular to the axis of the cavity, may also exist.
Simple cavity
A common example of longitudinal modes are the light wavelengths produced by a laser. In the simplest case, the laser's optical cavity is formed by two opposed plane (flat) mirrors surrounding the gain medium (a plane-parallel or Fabry–Pérot cavity). The allowed modes of the cavity are those where the mirror separation distance L is equal to an exact multiple of half the wavelength, λ:
where q is an integer known as the mode order.
In practice, the separation distance of the mirrors L is usually much greater than the wavelength of light λ, so the relevant values of q are large (around 105 to 106). The frequency separation between any two adjacent modes, q and q+1, in a material that is transparent at the laser wavelength, are given (for an empty linear resonator of length L) by Δν:
where c is the speed of light and n is the refractive index of the material (note: n≈1 in air).
Composite cavity
If the cavity is non-empty (i.e. contains one or more elements with different values of refractive index), the values of L used are the optical path lengths for each element. The frequency spacing of longitudinal modes in the cavity is then given by:
where ni is the refractive index of the i'th element of length Li.
More generally, the longitudinal modes may be found for any type of wave in a cavity by solving the relevant wave equation with the appropriate boundary conditions.
Both transverse and longitudinal waves may |
https://en.wikipedia.org/wiki/Developable%20surface | In mathematics, a developable surface (or torse: archaic) is a smooth surface with zero Gaussian curvature. That is, it is a surface that can be flattened onto a plane without distortion (i.e. it can be bent without stretching or compression). Conversely, it is a surface which can be made by transforming a plane (i.e. "folding", "bending", "rolling", "cutting" and/or "gluing"). In three dimensions all developable surfaces are ruled surfaces (but not vice versa). There are developable surfaces in four-dimensional space which are not ruled.
The envelope of a single parameter family of planes is called a developable surface.
Particulars
The developable surfaces which can be realized in three-dimensional space include:
Cylinders and, more generally, the "generalized" cylinder; its cross-section may be any smooth curve
Cones and, more generally, conical surfaces; away from the apex
The oloid and the sphericon are members of a special family of solids that develop their entire surface when rolling down a flat plane.
Planes (trivially); which may be viewed as a cylinder whose cross-section is a line
Tangent developable surfaces; which are constructed by extending the tangent lines of a spatial curve.
The torus has a metric under which it is developable, which can be embedded into three-dimensional space by the Nash embedding theorem and has a simple representation in four dimensions as the Cartesian product of two circles: see Clifford torus.
Formally, in mathematics, a developable surface is a surface with zero Gaussian curvature. One consequence of this is that all "developable" surfaces embedded in 3D-space are ruled surfaces (though hyperboloids are examples of ruled surfaces which are not developable). Because of this, many developable surfaces can be visualised as the surface formed by moving a straight line in space. For example, a cone is formed by keeping one end-point of a line fixed whilst moving the other end-point in a circle.
Application
Devel |
https://en.wikipedia.org/wiki/Helsinki%20Institute%20of%20Physics | The Helsinki Institute of Physics (HIP, , ) is a physics research institute operated jointly by University of Helsinki, Aalto University, University of Jyväskylä, Lappeenranta University of Technology and Tampere University of Technology. The operations of the institute began on September 1, 1996. The foundation of the institute was provided by the three previous Helsinki-based institutes: SEFT, TFT (University of Helsinki) and HTI (Helsinki University of Technology), which were merged into the new organization. The current director of the institute since 2017 has been prof. Katri Huitu. The institute is responsible for the Finnish research collaboration with CERN and Facility for Antiproton and Ion Research in Europe GmbH (FAIR).
The research is currently focused on following fields:
Theory Programme
Nuclear Structure for Weak and Astrophysical Processes
QCD and Strongly Interacting Gauge Theory
Domain Wall Dynamics
Cosmology of the Early and Late Universe
High Energy Phenomenology in the LHC Era
CMS Programme
CMS Experiment
CMS Upgrade
Tier-2 Operations
TOTEM
Technology Programme
Accelerator Technology
Green Big Data Project
Biomedical Imaging
Novel Instrumentation for Nuclear Safety, Security and Safeguards
Finnish Business Incubation Center of CERN Technologies
Nuclear Matter Programme
ALICE
ISOLDE
FAIR |
https://en.wikipedia.org/wiki/Optical%20computing | Optical computing or photonic computing uses light waves produced by lasers or incoherent sources for data processing, data storage or data communication for computing. For decades, photons have shown promise to enable a higher bandwidth than the electrons used in conventional computers (see optical fibers).
Most research projects focus on replacing current computer components with optical equivalents, resulting in an optical digital computer system processing binary data. This approach appears to offer the best short-term prospects for commercial optical computing, since optical components could be integrated into traditional computers to produce an optical-electronic hybrid. However, optoelectronic devices consume 30% of their energy converting electronic energy into photons and back; this conversion also slows the transmission of messages. All-optical computers eliminate the need for optical-electrical-optical (OEO) conversions, thus reducing electrical power consumption.
Application-specific devices, such as synthetic-aperture radar (SAR) and optical correlators, have been designed to use the principles of optical computing. Correlators can be used, for example, to detect and track objects, and to classify serial time-domain optical data.
Optical components for binary digital computer
The fundamental building block of modern electronic computers is the transistor. To replace electronic components with optical ones, an equivalent optical transistor is required. This is achieved by crystal optics (using materials with a non-linear refractive index). In particular, materials exist where the intensity of incoming light affects the intensity of the light transmitted through the material in a similar manner to the current response of a bipolar transistor. Such an optical transistor can be used to create optical logic gates, which in turn are assembled into the higher level components of the computer's central processing unit (CPU). These will be nonlinear optical c |
https://en.wikipedia.org/wiki/CHMOS | CHMOS refers to one of a series of Intel CMOS processes developed from their HMOS process. CHMOS stands for "complementary high-performance metal-oxide-silicon. It was first developed in 1981.
CHMOS was used in the Intel 80C51BH, a new version of their standard MCS-51 microcontroller. The chip was also used in later versions of Intel 8086, and the 80C88, which were fully static version of the Intel 8088. The Intel 80386 was made in 1.5 µm CHMOS III, and later in 1.0 µm CHMOS IV.
CHMOS III used 1.5 micron lithography, p-well processing, n-well processing, and two layers of metal.
CHMOS III-E used for the 12.5 MHz Intel 80C186 microprocessor. This technology uses 1 µm process for the EPROM.
CHMOS IV (H stands for High Speed) used 1.0 µm lithography. Many versions of the Intel 80486 were made in 1.0 µm CHMOS IV. Intel uses this technology on these 80C186EB and 80C188EB embedded processors.
CHMOS V used 0.8 µm lithography and 3 metal layers, and was used in later versions of the 80386, 80486, and i860.
See also
Depletion-load NMOS logic#Further development |
https://en.wikipedia.org/wiki/List%20of%20Japanese%20map%20symbols | This is a list of symbols appearing on Japanese maps. These symbols are called in the Japanese language.
Partial list of symbols for users with visual impairment
Official symbols according to the conventions of the Geographical Survey Institute of Japan appear with a circle below.
See also
(GSI)
External links
Japanese map symbols
This is a very good reference, it has separate links for each symbol.
Japanese map
Maps of Japan
Geography of Japan
Japan |
https://en.wikipedia.org/wiki/List%20of%20probability%20distributions | Many probability distributions that are important in theory or applications have been given specific names.
Discrete distributions
With finite support
The Bernoulli distribution, which takes value 1 with probability p and value 0 with probability q = 1 − p.
The Rademacher distribution, which takes value 1 with probability 1/2 and value −1 with probability 1/2.
The binomial distribution, which describes the number of successes in a series of independent Yes/No experiments all with the same probability of success.
The beta-binomial distribution, which describes the number of successes in a series of independent Yes/No experiments with heterogeneity in the success probability.
The degenerate distribution at x0, where X is certain to take the value x0. This does not look random, but it satisfies the definition of random variable. This is useful because it puts deterministic variables and random variables in the same formalism.
The discrete uniform distribution, where all elements of a finite set are equally likely. This is the theoretical distribution model for a balanced coin, an unbiased die, a casino roulette, or the first card of a well-shuffled deck.
The hypergeometric distribution, which describes the number of successes in the first m of a series of n consecutive Yes/No experiments, if the total number of successes is known. This distribution arises when there is no replacement.
The negative hypergeometric distribution, a distribution which describes the number of attempts needed to get the nth success in a series of Yes/No experiments without replacement.
The Poisson binomial distribution, which describes the number of successes in a series of independent Yes/No experiments with different success probabilities.
Fisher's noncentral hypergeometric distribution
Wallenius' noncentral hypergeometric distribution
Benford's law, which describes the frequency of the first digit of many naturally occurring data.
The ideal and robust soliton distributions.
Zipf's law or |
https://en.wikipedia.org/wiki/Sodium%20channel | Sodium channels are integral membrane proteins that form ion channels, conducting sodium ions (Na+) through a cell's membrane. They belong to the superfamily of cation channels.
Classification
They are classified into 2 types:
Function
In excitable cells such as neurons, myocytes, and certain types of glia, sodium channels are responsible for the rising phase of action potentials. These channels go through three different states called resting, active and inactive states. Even though the resting and inactive states would not allow the ions to flow through the channels the difference exists with respect to their structural conformation.
Selectivity
Sodium channels are highly selective for the transport of ions across cell membranes. The high selectivity with respect to the sodium ion is achieved in many different ways. All involve encapsulation of the sodium ion in a cavity of specific size within a larger molecule.
Voltage-gated sodium channels
Structure
Sodium channels consist of large alpha subunits that associate with accessory proteins, such as beta subunits. An alpha subunit forms the core of the channel and is functional on its own. When the alpha subunit protein is expressed by a cell, it is able to form a pore in the cell membrane that conducts Na+ in a voltage-dependent way, even if beta subunits or other known modulating proteins are not expressed. When accessory proteins assemble with α subunits, the resulting complex can display altered voltage dependence and cellular localization.
The alpha subunit consists of four repeat domains, labelled I through IV, each containing six membrane-spanning segments, labelled S1 through S6. The highly conserved S4 segment acts as the channel's voltage sensor. The voltage sensitivity of this channel is due to positive amino acids located at every third position. When stimulated by a change in transmembrane voltage, this segment moves toward the extracellular side of the cell membrane, allowing the channel to beco |
https://en.wikipedia.org/wiki/Bedtime%20story | A bedtime story is a traditional form of storytelling, where a story is told to a child at bedtime to prepare the child for sleep. The bedtime story has long been considered "a definite institution in many families".
The term "bedtime story" was coined by Louise Chandler Moulton in her 1873 book, Bed-time Stories. The scholar Robin Bernstein traces how the "ritual of an adult reading out loud to a child at bedtime formed mainly in the second half of the nineteenth century and achieved prominence in the early twentieth century in tandem with the rising belief that soothing rituals were necessary for children at the end of the day. The ritual resulted from and negotiated diverse phenomena: not only the growth of the picture book industry but also the spread of isolated sleeping in which children occupied individual bedrooms, the expansion of electricity and heating systems that shifted evening reading beyond the hearth to other domestic spaces, and a bevy of newly crowned psychological experts who persuaded parents that children needed" bedtime rituals. "By the middle of the twentieth
century," Bernstein writes, "the ritual had acquired acute symbolic meaning. Parents’ reading to children at bedtime became a metonym for proper parenting and an idealized middle- class childhood."
Reading bedtime stories yields multiple benefits for parents and children alike. The fixed routine of a bedtime story before sleeping can improve the child's brain development, language mastery, and logical thinking skills. The storyteller-listener relationship creates an emotional bond between the parent and the child. Due to "the strength of the imitative instinct" of a child, the parent and the stories that they tell act as a model for the child to follow.
Bedtime stories are also useful for teaching the child abstract virtues such as sympathy, selflessness, and self-control, as most children are said to be "naturally sympathetic when they have experienced or can imagine the feelings o |
https://en.wikipedia.org/wiki/Epicotyl | An epicotyl is important for the beginning stages of a plant's life. It is the region of a seedling stem above the stalks of the seed leaves of an embryo plant. It grows rapidly, showing hypogeal germination, and extends the stem above the soil surface. A common misconception is that the epicotyl, being closer to the apex of the plant, is the first part to emerge after germination - rather, the hypocotyl, the region of the stem between the point of attachment of the cotyledons and the root - forms a hook during hypogeal germination and pushes out of the soil, allowing the more delicate tissues of the plumules and apical meristem to avoid damage from pushing through the soil. The epicotyl will expand and form the point of attachment of the shoot apex and leaf primordia or "first true leaves". Cotyledons may remain belowground or be pushed up aboveground with the growing stem depending on the plant species in question.
In plant physiology, the epicotyl is the embryonic shoot above the cotyledons. In most plants the epicotyl will eventually develop into the leaves of the plant. In dicots, the hypocotyl is what appears to be the base stem under the spent withered cotyledons, and the shoot just above that is the epicotyl. In monocot plants, the first shoot that emerges from the ground or from the seed is the epicotyl, from which the first shoots and leaves emerge.
Lengthening of the epicotyl is thought to be controlled by the phytochrome photoreceptors.
See also
Hypocotyl
Radicle
Plumule
External links
"epicotyl." A Dictionary of Biology. 2004. Encyclopedia.com. 3 Dec. 2015
Plant morphology |
https://en.wikipedia.org/wiki/Isotropic%20coordinates | In the theory of Lorentzian manifolds, spherically symmetric spacetimes admit a family of nested round spheres. There are several different types of coordinate chart which are adapted to this family of nested spheres; the best known is the Schwarzschild chart, but the isotropic chart is also often useful.
The defining characteristic of an isotropic chart is that its radial coordinate (which is different from the radial coordinate of a Schwarzschild chart) is defined so that light cones appear round. This means that (except in the trivial case of a locally flat manifold), the angular isotropic coordinates do not faithfully represent distances within the nested spheres, nor does the radial coordinate faithfully represent radial distances. On the other hand, angles in the constant time hyperslices are represented without distortion, hence the name of the chart.
Isotropic charts are most often applied to static spherically symmetric spacetimes in metric theories of gravitation such as general relativity, but they can also be used in modeling a spherically pulsating fluid ball, for example. For isolated spherically symmetric solutions of the Einstein field equation, at large distances, the isotropic and Schwarzschild charts become increasingly similar to the usual polar spherical chart on Minkowski spacetime.
Definition
In an isotropic chart (on a static spherically symmetric spacetime), the metric (aka line element) takes the form
Depending on context, it may be appropriate to regard as undetermined functions of the radial coordinate (for example, in deriving an exact static spherically symmetric solution of the Einstein field equation). Alternatively, we can plug in specific functions (possibly depending on some parameters) to obtain an isotropic coordinate chart on a specific Lorentzian spacetime.
Killing vector fields
The Lie algebra of Killing vector fields of a spherically symmetric static spacetime takes the same form in the isotropic chart as in the Sc |
https://en.wikipedia.org/wiki/Blastema | A blastema (Greek βλάστημα, "offspring") is a mass of cells capable of growth and regeneration into organs or body parts. The changing definition of the word "blastema" has been reviewed by Holland (2021). A broad survey of how blastema has been used over time brings to light a somewhat involved history. The word entered the biomedical vocabulary in 1799 to designate a sinister acellular slime that was the starting point for the growth of cancers, themselves, at the time, thought to be acellular, as reviewed by Hajdu (2011, Cancer 118: 1155-1168). Then, during the early nineteenth century, the definition broadened to include growth zones (still considered acellular) in healthy, normally developing plant and animal embryos. Contemporaneously, cancer specialists dropped the term from their vocabulary, perhaps because they felt a term connoting a state of health and normalcy was not appropriate for describing a pathological condition. During the middle decades of the nineteenth century, Schleiden and Schwann proposed the cell theory, and Remak and Virchow insisted that cells can only be generated by division of existing ones. Consequently, the conception of the blastema changed from acellular to cellular. More specifically, the term came to designate a population of embryonic cells that gave rise to a particular tissue. In short, the term blastema started being used to refer to what modern embryologists increasingly began calling a rudiment or Anlage. Importantly, the term blastema did not yet refer to a mass of undifferentiated-looking cells that accumulates relatively early in a regenerating body part. For instance, Morgan (1900), does not use the term even once in his classic book, “Regeneration.” It was not until the eve of World War 1 that Fritsch (1911, Zool. Jb. Zool. Physiol. 30: 377-472) introduced the term blastema in the modern sense, as now used by contemporary students of regeneration. Currently, the old usage of blastema to refer to a normal embryological |
https://en.wikipedia.org/wiki/Real-Time%20Messaging%20Protocol | Real-Time Messaging Protocol (RTMP) is a communication protocol for streaming audio, video, and data over the Internet. Originally developed as a proprietary protocol by Macromedia for streaming between Flash Player and the Flash Communication Server, Adobe (which acquired Macromedia) has released an incomplete version of the specification of the protocol for public use.
The RTMP protocol has multiple variations:
RTMP proper, the "plain" protocol which works on top of Transmission Control Protocol (TCP) and uses port number 1935 by default.
RTMPS, which is RTMP over a Transport Layer Security (TLS/SSL) connection.
RTMPE, which is RTMP encrypted using Adobe's own security mechanism. While the details of the implementation are proprietary, the mechanism uses industry standard cryptographic primitives.
RTMPT, which is encapsulated within HTTP requests to traverse firewalls. RTMPT is frequently found utilizing cleartext requests on TCP ports 80 and 443 to bypass most corporate traffic filtering. The encapsulated session may carry plain RTMP, RTMPS, or RTMPE packets within.
RTMFP, which is RTMP over User Datagram Protocol (UDP) instead of TCP, replacing RTMP Chunk Stream. The Secure Real-Time Media Flow Protocol suite has been developed by Adobe Systems and enables end‐users to connect and communicate directly with each other (P2P).
While the primary motivation for RTMP was to be a protocol for playing Flash video, it is also used in some other applications, such as the Adobe LiveCycle Data Services ES.
Basic operation
RTMP is a TCP-based protocol which maintains persistent connections and allows low-latency communication. To deliver streams smoothly and transmit as much information as possible, it splits streams into fragments, and their size is negotiated dynamically between the client and server. Sometimes, it is kept unchanged; the default fragment sizes are 64 bytes for audio data, and 128 bytes for video data and most other data types. Fragments from diffe |
https://en.wikipedia.org/wiki/Static%20spherically%20symmetric%20perfect%20fluid | In metric theories of gravitation, particularly general relativity, a static spherically symmetric perfect fluid solution (a term which is often abbreviated as ssspf) is a spacetime equipped with suitable tensor fields which models a static round ball of a fluid with isotropic pressure.
Such solutions are often used as idealized models of stars, especially compact objects such as white dwarfs and especially neutron stars. In general relativity, a model of an isolated star (or other fluid ball) generally consists of a fluid-filled interior region, which is technically a perfect fluid solution of the Einstein field equation, and an exterior region, which is an asymptotically flat vacuum solution. These two pieces must be carefully matched across the world sheet of a spherical surface, the surface of zero pressure. (There are various mathematical criteria called matching conditions for checking that the required matching has been successfully achieved.) Similar statements hold for other metric theories of gravitation, such as the Brans–Dicke theory.
In this article, we will focus on the construction of exact ssspf solutions in our current Gold Standard theory of gravitation, the theory of general relativity. To anticipate, the figure at right depicts (by means of an embedding diagram) the spatial geometry of a simple example of a stellar model in general relativity. The euclidean space in which this two-dimensional Riemannian manifold (standing in for a three-dimensional Riemannian manifold) is embedded has no physical significance, it is merely a visual aid to help convey a quick impression of the kind of geometrical features we will encounter.
Short history
We list here a few milestones in the history of exact ssspf solutions in general relativity:
1916: Schwarzschild fluid solution,
1939: The relativistic equation of hydrostatic equilibrium, the Oppenheimer-Volkov equation, is introduced,
1939: Tolman gives seven ssspf solutions, two of which are suitable |
https://en.wikipedia.org/wiki/Chronosophy | Chronosophy is the neologistic designation given by scholar Julius Thomas (J.T.) Fraser to "the interdisciplinary and normative study of time sui generis."
Overview
Etymology
Fraser derived the term from the Ancient Greek: χρόνος, chronos, "time" and σοφία, sophia, "wisdom". Chronosophia is thus defined as the "specific human skill or knowledge . . . pertaining to time . . . [which] all men seem to possess to some degree . . .".
Purpose
Fraser outlined the purpose of the discipline of chronosophy in five intentions, as follows:
to encourage the search for new knowledge related to time;
to set up and apply criteria regarding which fields of knowledge contribute to an understanding of time, and what they may contribute;
to assist in epistemological studies, especially in those related to the structure of knowledge;
to provoke communication between the humanities and the sciences using time as the common theme; and
to help us learn more about the nature of time by providing channels for the direct confrontation of a multitude of views.
Assumptions
According to Fraser, any pursuit of chronosophical knowledge necessarily makes two assumptions:
When specialists speak of 'time', they speak of various aspects of the same entity.
Said entity is amenable to study by the methods of the sciences, can be made a meaningful subject of contemplation by the reflective mind, and can be used as proper material for intuitive interpretation by the creative artist.
Fraser labeled these two assumptions the unity of time. Together they amount to the proposition that all of us, working separately, are nevertheless headed toward the same central idea (i.e., chronosophia).
In contradistinction to the aforementioned, Fraser posits the diversity of time: the existence of time's myriad manifestations, which "hardly needs proof; it is all too apparent."
The continued qualitative and quantitative mediation of the unresolvable conflict between the unity and diversity of time would t |
https://en.wikipedia.org/wiki/Glomalin | Glomalin is a hypothetical glycoprotein produced abundantly on hyphae and spores of arbuscular mycorrhizal (AM) fungi in soil and in roots. Glomalin was proposed in 1996 by Sara F. Wright, a scientist at the USDA Agricultural Research Service, but it was not isolated and described yet. The name comes from Glomerales, an order of fungi. Most AM fungi are of the division Glomeromycota. An elusive substance, it is mostly assumed to have a glue-like effect on soil, but it has not been isolated yet.
Definition and controversy
The specific protein glomalin has not yet been isolated and described. What has been described is an extraction process involving heat and citrate, producing a mixture containing a substance that is reactive to a monoclonal antibody Mab32B11 raised against crushed AM fungi spores. The substance is then provisionally named "glomalin". As many laboratories do not have the equipment to perform an antibody-based isolation (ELISA), a crude mixture called glomalin-related soil proteins (GRSP) is used to refer to the extract portion reactive to the Bradford protein assay. There is significant confusion between the ideal glomalin protein, the antibody-reactive extract portion termed "glomalin", and GRSP.
"Glomalin" was first detected by the Mab32B11 ELISA assay in 1987. According to the scientist that proposed the hypothetical protein, Sarah F. Wright, it eluded extraction until 1996 because "It requires an unusual effort to dislodge glomalin for study: a bath in citrate combined with heating at 250 °F (121 °C) for at least an hour.... No other soil glue found to date required anything as drastic as this." However, using advanced analytical methods in 2010, the citrate-heating extraction procedure for GRSP was proven to co-extract humic substances, so it is still not clear if this "glue effect" comes from glomalin or the other substances that are co-extracted using that method.
Description
Based on her extraction, Wright thinks the "glomalin molecul |
https://en.wikipedia.org/wiki/Russian%20460%20metre%20radio%20mast | The Russian 460 metres radio masts are among the most secret supertall structures ever built. Three such masts, which were developed by Stako, were erected in mid-1980s near Inta, Dudinka and Taymylyr as masts for the North Siberian Chayka Chain for transmitting navigation signals on 100 kHz with 1200 kW.
All these masts are grounded lattice structures of tubular steel elements with triangular cross section. The side length of the triangle of the mast body is 3.6 metres. Each of these masts is guyed in 6 levels.
These masts were at completion the tallest structures in Asia and are still the second-tallest in Russia.
In 2003 at Moscow Radio Centre 13 a guyed mast for FM-transmission of the same type was built, which is however just 300 metres and not 460 metres tall. It is guyed in 4 levels.
On September 24, 2009, the mast at Taymylyr was demolished by explosives, which was the tallest object ever demolished in this way.
External links
http://ru-abandoned.livejournal.com/713371.html
https://web.archive.org/web/20110816150649/http://www.internavigation.ru/page.phtml?p=95
Towers in Russia
Radio masts and towers
Towers built in the Soviet Union
Radio in the Soviet Union |
https://en.wikipedia.org/wiki/CEBus | CEBus(r), short for Consumer Electronics Bus, also known as EIA-600, is a set of electrical standards and communication protocols for electronic devices to transmit commands and data. It is suitable for devices in households and offices to use, and might be useful for utility interface and light industrial applications.
History
In 1984, members of the Electronic Industries Alliance (EIA) identified a need for standards that included more capability than the de facto home automation standard X10. X10 provided blind transmission of the commands ON, OFF, DIM, BRIGHT, ALL LIGHTS ON, and ALL UNITS OFF over powerline carrier, and later infrared and short range radio mediums. Over a six-year period, engineers representing international companies met on a regular basis and developed a proposed standard. They called this standard CEBus (pronounced "see bus"). The CEBus standard was released in September 1992.
CEBus is an open architecture set of specification documents which define protocols for products to communicate through power line wire, low voltage twisted pair wire, coaxial cable, infrared, RF, and fiber optics.
The CEBus Standard was developed on the foundation of an IR (infrared) protocol developed by GE (General Electric). This work was transferred to the EIA at the beginning of the EIA's involvement, under the plan that it would be expanded then maintained by the EIA.
Technology
Powerline carrier
The CEBus standard includes such things as spread spectrum modulation on the power line. Spread spectrum involves starting a modulation at one frequency, and altering the frequency during its cycle. The CEBus power line standard begins each burst at 100 kHz, and increases linearly to 400 kHz during a 100 microsecond duration. Both the bursts (referred to as "superior" state) and the absence of burst (referred to as the "inferior" state) create similar digits, so a pause in between is not necessary.
A digit 1 is created by an inferior or superior state that l |
https://en.wikipedia.org/wiki/K%C3%B6nig%27s%20theorem%20%28kinetics%29 | In kinetics, König's theorem or König's decomposition is a mathematical relation derived by Johann Samuel König that assists with the calculations of angular momentum and kinetic energy of bodies and systems of particles.
For a system of particles
The theorem is divided in two parts.
First part of König's theorem
The first part expresses the angular momentum of a system as the sum of the angular momentum of the centre of mass and the angular momentum applied to the particles relative to the center of mass.
Proof
Considering an inertial reference frame with origin O, the angular momentum of the system can be defined as:
The position of a single particle can be expressed as:
And so we can define the velocity of a single particle:
The first equation becomes:
But the following terms are equal to zero:
So we prove that:
where M is the total mass of the system.
Second part of König's theorem
The second part expresses the kinetic energy of a system of particles in terms of the velocities of the individual particles and the centre of mass.
Specifically, it states that the kinetic energy of a system of particles is the sum of the kinetic energy associated to the movement of the center of mass and the kinetic energy associated to the movement of the particles relative to the center of mass.
Proof
The total kinetic energy of the system is:
Like we did in the first part, we substitute the velocity:
We know that so if we define:
we're left with:
For a rigid body
The theorem can also be applied to rigid bodies, stating that the kinetic energy K of a rigid body, as viewed by an observer fixed in some inertial reference frame N, can be written as:
where is the mass of the rigid body; is the velocity of the center of mass of the rigid body, as viewed by an observer fixed in an inertial frame N; is the angular momentum of the rigid body about the center of mass, also taken in the inertial frame N; and is the angular velocity of the rigid body R |
https://en.wikipedia.org/wiki/Freshers%27%20flu | Freshers' flu is a name commonly given to a battery of illnesses contracted by new students (freshers) during the first few weeks at a university, and colleges of further education in some form; common symptoms include fever, sore throat, severe headache, coughing and general discomfort. The illnesses may or may not include actual flu and is often simply a bad cold.
Causes
The most likely cause is the convergence of large numbers of people arriving from all over the world; this is a particularly elevated risk due to the COVID-19 pandemic. The poor diet and heavy consumption of alcohol during freshers' week is also reported as a cause for many of the illnesses contracted during this time. "Stress, which may be induced by tiredness, combined with a poor diet, late nights and too much alcohol, can weaken the immune system and be a recipe for ill health. All this can make students and staff working with the students more susceptible to infections within their first weeks of term." In addition to this, nearly all university academic years in the UK commence around the end of September or beginning of October, which "marks the start of the annual flu season". The increased susceptibility to illness from late nights, heavy alcohol consumption and stress peaks 2–4 weeks after arrival at university and happens to coincide with the seasonal surge in the outbreaks of colds and flu in the Northern Hemisphere.
Other effects
As well as the usual viral effects, freshers' flu can also have some psychological effects. These effects arise where the stress of leaving home and other consequences of being independent, not to mention various levels of homesickness and the attempts at making new friends, can further weaken the immune system, increasing susceptibility to illness.
See also
Freshman 15 |
https://en.wikipedia.org/wiki/Parameter%20space | The parameter space is the space of possible parameter values that define a particular mathematical model, often a subset of finite-dimensional Euclidean space. Often the parameters are inputs of a function, in which case the technical term for the parameter space is domain of a function. The ranges of values of the parameters may form the axes of a plot, and particular outcomes of the model may be plotted against these axes to illustrate how different regions of the parameter space produce different types of behavior in the model.
In statistics, parameter spaces are particularly useful for describing parametric families of probability distributions. They also form the background for parameter estimation. In the case of extremum estimators for parametric models, a certain objective function is maximized or minimized over the parameter space. Theorems of existence and consistency of such estimators require some assumptions about the topology of the parameter space. For instance, compactness of the parameter space, together with continuity of the objective function, suffices for the existence of an extremum estimator.
Examples
A simple model of health deterioration after developing lung cancer could include the two parameters gender and smoker/non-smoker, in which case the parameter space is the following set of four possibilities: .
The logistic map has one parameter, r, which can take any positive value. The parameter space is therefore positive real numbers.
For some values of r, this function ends up cycling round a few values, or fixed on one value. These long-term values can be plotted against r in a bifurcation diagram to show the different behaviours of the function for different values of r.
In a sine wave model the parameters are amplitude A > 0, angular frequency ω > 0, and phase φ ∈ S1. Thus the parameter space is
In complex dynamics, the parameter space is the complex plane C = { z = x + y i : x, y ∈ R }, where i2 = −1.
The famous Mandelbrot |
https://en.wikipedia.org/wiki/Beverly%20Clock | The Beverly Clock is a clock in the 3rd-floor lift foyer of the Department of Physics at the University of Otago, Dunedin, New Zealand. The clock is still running despite never having been manually wound since its construction in 1864 by Arthur Beverly.
Operation
The clock's mechanism is driven by variations in daily temperature and, to a lesser extent, in atmospheric pressure. Either causes the air in a airtight box to expand or contract, which pushes on a diaphragm. A temperature variation of over the course of each day creates approximately enough pressure to raise a one-pound weight by one inch (equivalent to ), which drives the clock mechanism.
A similar mechanism in a commercially available clock that operates on the same principle is the Atmos clock, manufactured by the Swiss watchmaker Jaeger-LeCoultre.
While the clock has not been wound since it was made, it has stopped on a number of occasions, such as when its mechanism needed cleaning or there was a mechanical failure, and when the Physics Department moved to new quarters. Also, on occasions when the ambient temperature does not fluctuate sufficiently to supply the requisite amount of energy, the clock will not function. However, after environmental parameters readjust, the clock begins operating again.
See also
Long-term experiment
Oxford Electric Bell (1840)
Pitch drop experiment (1927)
Cox's timepiece
Clock of the Long Now
Atmos clock, a commercially available clock working on a similar principle
Temperature gradient ocean glider |
https://en.wikipedia.org/wiki/Load-link/store-conditional | In computer science, load-linked/store-conditional (LL/SC), sometimes known as load-reserved/store-conditional (LR/SC), are a pair of instructions used in multithreading to achieve synchronization. Load-link returns the current value of a memory location, while a subsequent store-conditional to the same memory location will store a new value only if no updates have occurred to that location since the load-link. Together, this implements a lock-free, atomic, read-modify-write operation.
"Load-linked" is also known as load-link, load-reserved, and load-locked.
LL/SC was originally proposed by Jensen, Hagensen, and Broughton for the S-1 AAP multiprocessor at Lawrence Livermore National Laboratory.
Comparison of LL/SC and compare-and-swap
If any updates have occurred, the store-conditional is guaranteed to fail, even if the value read by the load-link has since been restored. As such, an LL/SC pair is stronger than a read followed by a compare-and-swap (CAS), which will not detect updates if the old value has been restored (see ABA problem).
Real implementations of LL/SC do not always succeed even if there are no concurrent updates to the memory location in question. Any exceptional events between the two operations, such as a context switch, another load-link, or even (on many platforms) another load or store operation, will cause the store-conditional to spuriously fail. Older implementations will fail if there are any updates broadcast over the memory bus. This is called weak LL/SC by researchers, as it breaks many theoretical LL/SC algorithms. Weakness is relative, and some weak implementations can be used for some algorithms.
LL/SC is more difficult to emulate than CAS. Additionally, stopping running code between paired LL/SC instructions, such as when single-stepping through code, can prevent forward progress, making debugging tricky.
Nevertheless, LL/SC is equivalent to CAS in the sense that either primitive can be implemented in terms of the other, in O(1) |
https://en.wikipedia.org/wiki/FR-V%20%28microprocessor%29 | The Fujitsu FR-V (Fujitsu RISC-VLIW) is one of the very few processors ever able to process both a very long instruction word (VLIW) and vector processor instructions at the same time, increasing throughput with high parallel computing while increasing performance per watt and hardware efficiency. The family was presented in 1999. Its design was influenced by the VPP500/5000 models of the Fujitsu VP/2000 vector processor supercomputer line.
Featuring a 1–8 way very long instruction word (VLIW, Multiple Instruction Multiple Data (MIMD), up to 256 bit) instruction set it additionally uses a 4-way single instruction, multiple data (SIMD) vector processor core. A 32-bit RISC instruction set in the superscalar core is combined with most variants integrating a dual 16-bit media processor also in VLIW and vector architecture. Each processor core is superpipelined as well as 4-unit superscalar.
A typical integrated circuit integrates a system on a chip and further multiplies speed by integrating multiple cores. Due to the very low power requirements it is a solution even for battery-powered applications.
Variants
The family started with the FR-500, includes FR-300, FR-400, FR-450, FR-550 and FR1000 architecture 32-bit processors, can run Linux, RTLinux, VxWorks, eCos, or ITRON and is also supported by the Softune Integrated development environment and the GNU Compiler Collection or GNUPro.
It is often used for image processing or video processing with most variants including a dual 16-bit media-processor.
Technology
The 2005 presented FR1000 uses a core with 8-way 256-bit VLIW (MIMD) filling its superpipeline as well as a 4-unit superscalar architecture (Integer (ALU)-, Floating-point- and two media-processor-units), further increasing its peak performance of each core to up to 28 instructions per clock cycle. Like other VLIW-architectures 1 way is needed to load the next 256-bit instruction: 7-ways usable. Due to the used 4-way single instruction, multiple data (SIMD |
https://en.wikipedia.org/wiki/Parametric%20model | In statistics, a parametric model or parametric family or finite-dimensional model is a particular class of statistical models. Specifically, a parametric model is a family of probability distributions that has a finite number of parameters.
Definition
A statistical model is a collection of probability distributions on some sample space. We assume that the collection, , is indexed by some set . The set is called the parameter set or, more commonly, the parameter space. For each , let denote the corresponding member of the collection; so is a cumulative distribution function. Then a statistical model can be written as
The model is a parametric model if for some positive integer .
When the model consists of absolutely continuous distributions, it is often specified in terms of corresponding probability density functions:
Examples
The Poisson family of distributions is parametrized by a single number :
where is the probability mass function. This family is an exponential family.
The normal family is parametrized by , where is a location parameter and is a scale parameter:
This parametrized family is both an exponential family and a location-scale family.
The Weibull translation model has a three-dimensional parameter :
The binomial model is parametrized by , where is a non-negative integer and is a probability (i.e. and ):
This example illustrates the definition for a model with some discrete parameters.
General remarks
A parametric model is called identifiable if the mapping is invertible, i.e. there are no two different parameter values and such that .
Comparisons with other classes of models
Parametric models are contrasted with the semi-parametric, semi-nonparametric, and non-parametric models, all of which consist of an infinite set of "parameters" for description. The distinction between these four classes is as follows:
in a "parametric" model all the parameters are in finite-dimensional parameter spaces;
a model is "n |
https://en.wikipedia.org/wiki/Super%20Hydlide | Super Hydlide is an action role-playing game for the Sega Genesis/Mega Drive. It was originally released in 1987 in Japan only under the title for the MSX, MSX2, and PC-8801mkII SR. It's the third game in the Hydlide series. Ports were also released for the X1, Famicom, X68000, and Microsoft Windows. The game was developed by Hydlide series veterans T&E Soft and released worldwide on the Sega Genesis / Mega Drive on October 6, 1989, in Japan, early 1990 in the United States, and 1991 in Europe. This remake evidences substantial graphical upgrades to the original Hydlide 3, though the gameplay remains largely identical. Before its release, it was called Hollo Fighter in some Sega advertising material and was one of the first third party published titles to be released in the U.S, the other being Air Diver.
Story
Many years after the events of Hydlide II, an explosion of flames appeared near The City of the Woods. After that, monsters spread throughout the world. A young man is chosen to find the source of the evil.
Gameplay
The game incorporates a 'good/evil character' morality/alignment system. Like its predecessor Hydlide II: Shine of Darkness (1985), the player has a morality meter that can be aligned with either Justice, Normal, or Evil. The game has both good and evil monsters. Evil monsters attack the player character on sight, while good monsters only attack if the player character attacks them first. Killing any monster, good or evil, results in a reward of experience points, money, and occasionally a piece of equipment. However, if the player kills a good monster, points are lost from a statistic called "MF" (Moral Fiber). If the player's MF stat drops to zero, frequent traps will appear across the world. If the player manages to keep it over 100, rewards appear in the form of random items found around Fairyland. Unlike Hydlide II, the morality meter no longer affects the way in which the townsfolk react to the player.
The game also features an in-game c |
https://en.wikipedia.org/wiki/Potassium%20metabisulfite | Potassium metabisulfite, K2S2O5, also known as potassium pyrosulfite, is a white crystalline powder with a pungent odour. It is mainly used as an antioxidant or chemical sterilant. As a disulfite, it is chemically very similar to sodium metabisulfite, with which it is sometimes used interchangeably. Potassium metabisulfite has a monoclinic crystal structure.
Preparation and reactions
Potassium metabisulfite can be prepared by treating a solution of potassium hydroxide with sulfur dioxide.
2 SO2 + 2 KOH → K2S2O5 + H2O
It decomposes at 190 °C, yielding potassium sulfite and sulfur dioxide:
K2S2O5 → K2SO3 + SO2
Uses
It is used as a food additive, also known as E224. It is restricted in use and may cause allergic reactions in some sensitive persons.
Wine
Potassium metabisulfite is a common wine or must additive, in which it forms sulfur dioxide (SO2). Sulfur dioxide is a disinfectant. It also acts as a potent antioxidant, protecting both the color and delicate flavors of wine.
A high dose would be 3 grams of potassium metabisulfite per six-gallon bucket of must (yielding roughly 75 ppm of SO2) prior to fermentation; then 6 grams per six-gallon bucket (150 ppm of SO2) at bottling. Some countries regulate the SO2 content of wines.
Winemaking equipment is sanitized by spraying with a 1% SO2 (2 tsp potassium metabisulfite per L) solution.
Beer
Potassium metabisulfite is sometimes used in the brewing industry to inhibit the growth of wild bacteria and fungi. This step is called 'stabilizing'. It is also used to neutralize monochloramine from tap water. It is used both by homebrewers and commercial brewers alike. It is not used as much for brewing beer, because the wort is almost always boiled, which kills most microorganisms.
Other uses
Potassium metabisulfite is sometimes added to lemon juice as a preservative.
Potassium metabisulfite is used in the textile industry for dyeing and cotton printing.
Potassium metabisulfite is sometimes used to precipitat |
https://en.wikipedia.org/wiki/HERA-B | The HERA-B detector was a particle physics experiment at the HERA accelerator at the German national laboratory DESY that collected data from 1993 to 2003. It measured 8 m × 20 m × 9 m and weighed 1000 tons. The HERA-B collaboration consisted of some 250 scientists from 32 institutes in 13 countries.
Its primary aim was to measure CP violation in the decays of heavy B mesons in the late 1990s, several years ahead of the Large Hadron Collider and B Factory programs. Unlike most particle physics detectors, the particles were produced not by colliding two circulating beams head-on, nor by slamming the beam into a stationary target, but by moving a thin wire target directly into the waste 'halo' of the circulating proton beam of the HERA accelerator. The beam was unaffected by this 'scraping' but the collision rate produced could be made extremely high, around 5 to 10 million interactions per second (5–10 MHz). The collaboration developed a novel scheme for moving the wires and the vertex detectors very close to the beam (less than one centimetre), using a vacuum chamber and motorised 'arms', had to be developed.
External links
HERA-B webpage
HERA-B experiment record on INSPIRE-HEP |
https://en.wikipedia.org/wiki/The%20Internet%20Pilot%20to%20Physics | TIPTOP (fully known as The Internet Pilot to Physics) was a web site operated in collaboration between Kenneth Bodin-Holmlund at Umeå University, Mikko Karttunen at McGill University and Guenther Nowotny at the Technical University of Vienna during 1994–1998, and it was originally derived from Physics Around the World (PAW) that was initiated by Karttunen at McGill University.
In a historical perspective, PAW was one of the first web directories, listing various physics related resources. TIPTOP utilized (at the time) new technologies to handle a news system, a job database, a conference database, and an improved web directory for physics. TIPTOP was the first major site to use PHP with mySQL, today a highly popular combination. Already in 1995, TIPTOP also had one of the first embryos of a wiki, called the Living Encyclopedia of Physics, that offered community based-editing, an editorial system and peer review, as well as automatic cross linking. |
https://en.wikipedia.org/wiki/Detached%20eddy%20simulation | Detached eddy simulation (DES) is a modification of a Reynolds-averaged Navier–Stokes equations (RANS) model in which the model switches to a subgrid scale formulation in regions fine enough for large eddy simulation (LES) calculations.
Details
Regions near solid boundaries and where the turbulent length scale is less than the maximum grid dimension are assigned the RANS mode of solution. As the turbulent length scale exceeds the grid dimension, the regions are solved using the LES mode. Therefore, the grid resolution is not as demanding as pure LES, thereby considerably cutting down the cost of the computation. Though DES was initially formulated for the Spalart-Allmaras model, it can be implemented with other RANS models (Strelets, 2001), by appropriately modifying the length scale which is explicitly or implicitly involved in the RANS model. So while Spalart-Allmaras model based DES acts as LES with a wall model, DES based on other models (like two equation models) behave as a hybrid RANS-LES model. Grid generation is more complicated than for a simple RANS or LES case due to the RANS-LES switch. DES is a non-zonal approach and provides a single smooth velocity field across the RANS and the LES regions of the solution. |
https://en.wikipedia.org/wiki/UDP%20Helper%20Address | A UDP Helper Address is a special router configuration used to forward broadcast network traffic from a client machine on one subnet to a server in another subnet.
Usage example
The Internet Protocol requires every network interface controller to be assigned at least one unique IP address. Groups of machines with similar addresses are considered to be part of the same logical subnet. One method of assigning IP addresses is DHCP in which addresses typically are issued by a DHCP server running on one or more hosts. If one of these machines is on the same subnet as its clients, the DHCP server can respond to their broadcast DHCP requests and issue an address. But the DHCP servers may be hosted on a different subnet and, by default, most routers do not pass broadcast messages to nodes outside their own subnet.
To resolve this, a UDP helper address is established in the router configuration to forward broadcast network traffic outside the local subnet. If a DHCP client outside the DHCP server's subnet broadcasts an address request, it is the helper that forwards the message to the DHCP server. The server then chooses an address and sends the client a unicast message, using the helper to send the message back to the client's subnet. The address is reserved for a limited time while the DHCP server waits for a response. If the client responds with another broadcast message, the DHCP server distributes the address. Helper addresses also can be used to forward other UDP traffic (for example, BOOTP).
Implementation
Cisco's first implementation of this protocol was introduced in version 10 of their router software. It is implemented through the use of the router configuration commands ip helper-address and ip forward-protocol.
ip helper-address
To enable the forwarding of User Datagram Protocol (UDP) broadcasts, including BOOTP, received on an interface, use the ip helper-address command in interface configuration mode. To disable the forwarding of broadcast packets to |
https://en.wikipedia.org/wiki/Diffusion%20barrier | A diffusion barrier is a thin layer (usually micrometres thick) of metal usually placed between two other metals. It is done to act as a barrier to protect either one of the metals from corrupting the other.
Adhesion of a plated metal layer to its substrate requires a physical interlocking, inter-diffusion of the deposit or a chemical bonding between plate and substrate in order to work. The role of a diffusion barrier is to prevent or to retard the inter-diffusion of the two superposed metals. Therefore, to be effective, a good diffusion barrier requires inertness with respect to adjacent materials. To obtain good adhesion and a diffusion barrier simultaneously, the bonding between layers needs to come from a chemical reaction of limited range at both boundaries. Materials providing good adhesion are not necessarily good diffusion barriers and vice versa. Consequently, there are cases where two or more separate layers must be used to provide a proper interface between substrates.
Selection
While the choice of diffusion barrier depends on the final function, anticipated operating temperature, and service life, are critical parameters to select diffusion barrier materials. Many thin film metal combinations have been evaluated for their adhesion and diffusion barrier properties.
Aluminum provides good electrical and thermal conductivity, adhesion and reliability because of its oxygen reactivity and the self-passivation properties of its oxide.
Copper also easily reacts with oxygen but its oxides have poor adhesion properties. As for gold its virtue relies in its inertness, and ease of application; its problem is its cost.
Chromium has excellent adhesion to many materials because of its reactivity. Its affinity for oxygen forms a thin stable oxide coat on the outer surface, creating a passivation layer which prevents further oxidation of the chromium, and of the underlying metal (if any), even in corrosive environments. Chromium plating on steel for automotive |
https://en.wikipedia.org/wiki/Automated%20reasoning | In computer science, in particular in knowledge representation and reasoning and metalogic, the area of automated reasoning is dedicated to understanding different aspects of reasoning. The study of automated reasoning helps produce computer programs that allow computers to reason completely, or nearly completely, automatically. Although automated reasoning is considered a sub-field of artificial intelligence, it also has connections with theoretical computer science and philosophy.
The most developed subareas of automated reasoning are automated theorem proving (and the less automated but more pragmatic subfield of interactive theorem proving) and automated proof checking (viewed as guaranteed correct reasoning under fixed assumptions). Extensive work has also been done in reasoning by analogy using induction and abduction.
Other important topics include reasoning under uncertainty and non-monotonic reasoning. An important part of the uncertainty field is that of argumentation, where further constraints of minimality and consistency are applied on top of the more standard automated deduction. John Pollock's OSCAR system is an example of an automated argumentation system that is more specific than being just an automated theorem prover.
Tools and techniques of automated reasoning include the classical logics and calculi, fuzzy logic, Bayesian inference, reasoning with maximal entropy and many less formal ad hoc techniques.
Early years
The development of formal logic played a big role in the field of automated reasoning, which itself led to the development of artificial intelligence. A formal proof is a proof in which every logical inference has been checked back to the fundamental axioms of mathematics. All the intermediate logical steps are supplied, without exception. No appeal is made to intuition, even if the translation from intuition to logic is routine. Thus, a formal proof is less intuitive and less susceptible to logical errors.
Some consider the Corne |
https://en.wikipedia.org/wiki/Imaginary%20time | Imaginary time is a mathematical representation of time which appears in some approaches to special relativity and quantum mechanics. It finds uses in connecting quantum mechanics with statistical mechanics and in certain cosmological theories.
Mathematically, imaginary time is real time which has undergone a Wick rotation so that its coordinates are multiplied by the imaginary unit i. Imaginary time is not imaginary in the sense that it is unreal or made-up (any more than, say, irrational numbers defy logic), it is simply expressed in terms of what mathematicians call imaginary numbers.
Origins
In mathematics, the imaginary unit is the square root of , such that is defined to be . A number which is a direct multiple of is known as an imaginary number.
In certain physical theories, periods of time are multiplied by in this way. Mathematically, an imaginary time period may be obtained from real time via a Wick rotation by in the complex plane: .
Stephen Hawking popularized the concept of imaginary time in his book The Universe in a Nutshell.
In fact, the terms "real" and "imaginary" for numbers are just a historical accident, much like the terms "rational" and "irrational":
In cosmology
Derivation
In the Minkowski spacetime model adopted by the theory of relativity, spacetime is represented as a four-dimensional surface or manifold. Its four-dimensional equivalent of a distance in three-dimensional space is called an interval. Assuming that a specific time period is represented as a real number in the same way as a distance in space, an interval in relativistic spacetime is given by the usual formula but with time negated:
where , and are distances along each spatial axis and is a period of time or "distance" along the time axis (Strictly, the time coordinate is where is the speed of light, however we conventionally choose units such that ).
Mathematically this is equivalent to writing
In this context, may be either accepted as a feature of th |
https://en.wikipedia.org/wiki/Battery%20charger | A battery charger, recharger, or simply charger, is a device that stores energy in a battery by running an electric current through it. The charging protocol (how much voltage or current for how long, and what to do when charging is complete) depends on the size and type of the battery being charged. Some battery types have high tolerance for overcharging (i.e., continued charging after the battery has been fully charged) and can be recharged by connection to a constant voltage source or a constant current source, depending on battery type. Simple chargers of this type must be manually disconnected at the end of the charge cycle. Other battery types use a timer to cut off when charging should be complete. Other battery types cannot withstand over-charging, becoming damaged (reduced capacity, reduced lifetime), over heating or even exploding. The charger may have temperature or voltage sensing circuits and a microprocessor controller to safely adjust the charging current and voltage, determine the state of charge, and cut off at the end of charge. Chargers may elevate the output voltage proportionally with current to compensate for impedance in the wires.
A trickle charger provides a relatively small amount of current, only enough to counteract self-discharge of a battery that is idle for a long time. Some battery types cannot tolerate trickle charging; attempts to do so may result in damage. Lithium-ion batteries cannot handle indefinite trickle charging. Slow battery chargers may take several hours to complete a charge. High-rate chargers may restore most capacity much faster, but high rate chargers can be more than some battery types can tolerate. Such batteries require active monitoring of the battery to protect it from overcharging. Electric vehicles ideally need high-rate chargers. For public access, installation of such chargers and the distribution support for them is an issue in the proposed adoption of electric cars.
C-rate
Charge and discharge rates a |
https://en.wikipedia.org/wiki/Quadratrix | In geometry, a quadratrix () is a curve having ordinates which are a measure of the area (or quadrature) of another curve. The two most famous curves of this class are those of Dinostratus and E. W. Tschirnhaus, which are both related to the circle.
Quadratrix of Dinostratus
The quadratrix of Dinostratus (also called the quadratrix of Hippias) was well known to the ancient Greek geometers, and is mentioned by Proclus, who ascribes the invention of the curve to a contemporary of Socrates, probably Hippias of Elis. Dinostratus, a Greek geometer and disciple of Plato, discussed the curve, and showed how it effected a mechanical solution of squaring the circle. Pappus, in his Collections, treats its history, and gives two methods by which it can be generated.
Let a helix be drawn on a right circular cylinder; a screw surface is then obtained by drawing lines from every point of this spiral perpendicular to its axis. The orthogonal projection of a section of this surface by a plane containing one of the perpendiculars and inclined to the axis is the quadratrix.
A right cylinder having for its base an Archimedean spiral is intersected by a right circular cone which has the generating line of the cylinder passing through the initial point of the spiral for its axis. From every point of the curve of intersection, perpendiculars are drawn to the axis. Any plane section of the screw (plectoidal of Pappus) surface so obtained is the quadratrix.
Another construction is as follows. is a quadrant in which the line and the arc are divided into the same number of equal parts. Radii are drawn from the centre of the quadrant to the points of division of the arc, and these radii are intersected by the lines drawn parallel to and through the corresponding points on the radius . The locus of these intersections is the quadratrix.
Letting be the origin of the Cartesian coordinate system, be the point , units from the origin along the -axis, and be the point , units from |
https://en.wikipedia.org/wiki/Active%20record%20pattern | In software engineering, the active record pattern is an architectural pattern. It is found in software that stores in-memory object data in relational databases. It was named by Martin Fowler in his 2003 book Patterns of Enterprise Application Architecture. The interface of an object conforming to this pattern would include functions such as Insert, Update, and Delete, plus properties that correspond more or less directly to the columns in the underlying database table.
The active record pattern is an approach to accessing data in a database. A database table or view is wrapped into a class. Thus, an object instance is tied to a single row in the table. After creation of an object, a new row is added to the table upon save. Any object loaded gets its information from the database. When an object is updated, the corresponding row in the table is also updated. The wrapper class implements accessor methods or properties for each column in the table or view.
This pattern is commonly used by object persistence tools and in object–relational mapping (ORM). Typically, foreign key relationships will be exposed as an object instance of the appropriate type via a property.
Implementations
Implementations of the concept can be found in various frameworks for many programming environments. For example, if there is a table parts in a database with columns name (string type) and price (number type), and the Active Record pattern is implemented in the class Part, the pseudo-code
will create a new row in the parts table with the given values, and is roughly equivalent to the SQL command
INSERT INTO parts (name, price) VALUES ('Sample part', 123.45);
Conversely, the class can be used to query the database:
This will find a new Part object based on the first matching row from the parts table whose name column has the value "gearbox". The SQL command used might be similar to the following, depending on the SQL implementation details of the database:
SELECT * FROM parts WHERE |
https://en.wikipedia.org/wiki/159%20%28number%29 | 159 (one hundred [and] fifty-nine) is a natural number following 158 and preceding 160.
In mathematics
159 is:
the sum of 3 consecutive prime numbers: 47 + 53 + 59.
a Woodall number.
equal to the sum of the squares of the digits of its own square in base 15.
Only 5 numbers (greater than 1) have this property in base 15, none in base 10.
written CLIX in Roman numeral, which spells a proper noun with multiple meanings.
Given 159, the Mertens function returns 0.
In astronomy
159 Aemilia is a large Main belt asteroid
NGC 159 is a galaxy in the constellation of Phoenix
The Saros number of the solar eclipse series which will begin on May 23, 2134 and end June 17, 3378. The duration of Saros series 159 is 1244.0 years, and it will contain 70 solar eclipses
The Saros number of the lunar eclipse series, which will begin on September 9, 2147 and end November 7, 3445. The duration of Saros series 159 is 1298.1 years, and it will contain 73 lunar eclipses
159P/LONEOS is a periodic comet in the Solar System
In geography
The state of Georgia has 159 counties
Sherwood No. 159, Saskatchewan is a rural municipality in Saskatchewan, Canada
In the military
Aero L-159 ALCA (Advanced Light Combat Aircraft) is a Czechoslovakian-built multi-role combat aircraft in service with the Czech Air Force
was a United States Navy during World War II
was a United States Navy during World War II
was a United States Navy during World War II
was a United States Navy concrete barge during World War II
was a United States Navy concrete barge following World War II
was a United States Navy during World War II
was a United States Navy during World War II
In sports
In professional darts, 159 is the lowest score a player can achieve with no available checkout.
In transportation
The Alfa Romeo 159 compact executive car produced from 2005 to 2011
The Ferrari 159 S racecar
The Peugeot Type 159 was produced in 1919
The British Rail Class 159, a member of the Sprinter family) |
https://en.wikipedia.org/wiki/Venix | Venix is a discontinued version of the Unix operating system for low-end computers, developed by VenturCom, a "company that specialises in the skinniest implementations of Unix".
Overview
A working version of Venix/86 for the IBM PC XT was demoed at COMDEX in May 1983. It was based on Version 7 Unix with some enhancements from BSD (notably vi, more and csh) and custom inter-process communication mechanisms. It was the first licensed UNIX operating system available for the IBM PC and its compatibles, supported read/write access to a separate DOS/FAT-partition and could run in as little as 128 KB (256 KB - 512 KB recommended).
In September 1984, Venix/86 Encore was released; it supported a number of early PC-compatibles, including the AT&T 6300, the Zenith 150, the (first) NCR PC, and the Texas Instruments Professional Computer.
Venix Encore, which then became Venix 2.0, was still based on Version 7 Unix, and ran on the DEC Rainbow 100 (Venix/86R) as well as PCs (Venix/86 and /286). The system contained a number of enhancements, notably tools to access DOS files directly on a DOS/FAT-partition, and an updated ADB debugger. The system came in two flavors: a 2-user version priced at $800, and an 8-user version at $1,000. There were no technical differences between the two.
Confusingly, Venix 2.0 for the DEC PRO-380 microcomputer (Venix/PRO) was based "essentially" on System III. It no longer ran on the PRO-350. This is made clear in the ckermit 4E build instructions, which has a special target for Pro running Venix 1.0, but instructs the user to use the sysiii target for the Pro running Venix 2.0. These same sources also make it clear that Venix had an enhanced TTY interface relative to a pure V7 Unix System.
Venix 2.1 was released for at least the PC. Like the original Venix/86, it included a C compiler, a BASIC interpreter and added a Fortran 77 compiler as an option. An optional driver kit made it possible to develop hardware drivers for the system and generate |
https://en.wikipedia.org/wiki/195%20%28number%29 | 195 (one hundred [and] ninety-five) is the natural number following 194 and preceding 196.
In mathematics
195 is:
the sum of eleven consecutive primes: 3 + 5 + 7 + 11 + 13 + 17 + 19 + 23 + 29 + 31 + 37
the smallest number expressed as a sum of distinct squares in 16 different ways
a centered tetrahedral number
in the middle of a prime quadruplet (191, 193, 197, 199).
See also
195 (disambiguation) |
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