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https://en.wikipedia.org/wiki/Thick-film%20technology | Thick-film technology is used to produce electronic devices/modules such as surface mount devices modules, hybrid integrated circuits, heating elements, integrated passive devices and sensors. Main manufacturing technique is screen printing (stenciling), which in addition to use in manufacturing electronic devices can also be used for various graphic reproduction targets. It became one of the key manufacturing/miniaturisation techniques of electronic devices/modules during 1950s. Typical film thickness – manufactured with thick film manufacturing processes for electronic devices – is 0.0001 to 0.1 mm.
Thick-film circuits/modules are widely used in the automotive industry, both in sensors, e.g. mixture of fuel/air, pressure sensors, engine and gearbox controls, sensor for releasing airbags, ignitors to airbags; common is that high reliability is required, often extended temperature range also along massive thermocycling of circuits without failure. Other application areas are space electronics, consumer electronics, and various measurement systems where low cost and/or high reliability is needed.
The simplest form to utilise a thick film technology is a module substrate/board, where wiring is manufactured using thick film process. Additionally resistors and large tolerance capacitors can be manufactured with thick film methods. Thick film wiring can be made compatible with surface-mount technology (SMT), and if needed (due to tolerances and/or size requirements) surface-mountable parts (resistors, capacitors, ICs, etc.) can be assembled on a thick film substrate.
The manufacturing of thick film devices/modules is an additive process involving deposition of several (typically max 6–8) successive layers of conductive, resistive and dielectric layers onto an electrically insulating substrate using a screen-printing process.
As a low cost manufacturing method it is applicable to produce large volumes of discrete passive devices like resistors, thermistors, varistors |
https://en.wikipedia.org/wiki/Agumbe%20Rainforest%20Research%20Station | The Agumbe Rainforest Research Station (ARRS) is a field based conservation and research organisation situated inside the Agumbe Reserved Forest at Agumbe in the central Western Ghats of southern India. The Agumbe Reserved Forests receives an annual rainfall in excess of and is at an elevation of about above sea level. It forms a part of the Malnad-Kodagu corridor, which also includes the Someshwara, Mookambika, Bhadra, and Sharavati Wildlife Sanctuaries, Kudremukh National Park, and various other forest tracts and reserve forests around Kundapur, Shankaranarayana, Hosanagara, Sringeri, and Thirthahalli.
History
ARRS was founded in 2005, by leading Indian herpetologist Romulus Whitaker. Whitaker saw his very first king cobra (Ophiophagus hannah) here in 1971. He was also extremely taken by the reverence the people in the region showed for snakes, which was a major factor that drove him to establish a research station in Agumbe (Karnataka ). The land is a revenue land was legally procured, the construction and activities are eco friendly and pose no disturbance to the wildlife.
Activities
ARRS managed the world's first radio-telemetry project on the King Cobra (Ophiophagus hannah), which is also the first radio-telemetry study done on any snake in India. Insight gained from this ecological study is being put into practice into king cobra management in the region. ARRS researchers have witnessed various unique behaviors among the species including a male king cobra killing a possibly pregnant female, a rare behavior even among mammals.
ARRS conducts and facilitates a wide variety of research projects, ranging from rainforest ecology, behavioral and population ecology, phenology, geoinformatics and socio economics. Apart from research, ARRS focuses on education and outreach in the local community, schools and colleges. A well-developed volunteer and research intern programme makes the research station an ideal location for those interested in field based resear |
https://en.wikipedia.org/wiki/Rectilinear%20Steiner%20tree | The rectilinear Steiner tree problem, minimum rectilinear Steiner tree problem (MRST), or rectilinear Steiner minimum tree problem (RSMT) is a variant of the geometric Steiner tree problem in the plane, in which the Euclidean distance is replaced with the rectilinear distance. The problem may be formally stated as follows: given n points in the plane, it is required to interconnect them all by a shortest network which consists only of vertical and horizontal line segments. It can be shown that such a network is a tree whose vertices are the input points plus some extra points (Steiner points).
The problem arises in the physical design of electronic design automation. In VLSI circuits, wire routing is carried out by wires running only in vertical and horizontal directions, due to high computational complexity of the task. Therefore wire length is the sum of the lengths of vertical and horizontal segments, and the distance between two pins of a net is actually the rectilinear distance ("Manhattan distance") between the corresponding geometric points in the design plane.
Properties
It is known that the search for the RSMT may be restricted to the Hanan grid, constructed by drawing vertical and horizontal lines through each vertex.
Computational complexity
The RSMT is an NP-hard problem, and as with other NP-hard problems, common approaches to tackle it are approximate algorithms, heuristic algorithms, and separation of efficiently solvable special cases. An overview of the approaches to the problem may be found in the 1992 book by Hwang, Richards and Winter, The Steiner Tree Problem.
Special cases
Single-trunk Steiner trees
The single-trunk Steiner tree is a tree that consists of a single horizontal segment and some vertical segments. A minimum single-trunk Steiner tree problem (MSTST) may be found in linear time.
The idea is that STSTs for a given point set essentially have only one "degree of freedom", which is the position of the horizontal trunk. Furth |
https://en.wikipedia.org/wiki/Sun%27s%20curious%20identity | In combinatorics, Sun's curious identity is the following identity involving binomial coefficients, first established by Zhi-Wei Sun in 2002:
Proofs
After Sun's publication of this identity in 2002, five other proofs were obtained by various mathematicians:
Panholzer and Prodinger's proof via generating functions;
Merlini and Sprugnoli's proof using Riordan arrays;
Ekhad and Mohammed's proof by the WZ method;
Chu and Claudio's proof with the help of Jensen's formula;
Callan's combinatorial proof involving dominos and colorings. |
https://en.wikipedia.org/wiki/Sarah%20J.%20Greenwald | Sarah J. Greenwald is professor of mathematics at Appalachian State University and faculty affiliate of gender, women's and sexuality studies.
Research
Greenwald's research interests include geometry and the scholarship of teaching and learning. She also investigates connections between mathematics and society, such as women, minorities and popular culture. For example, she was part of a team that looked into allusions to mathematics in The Simpsons.
Education
In 1991, Greenwald graduated summa cum laude with honors in mathematics from Union College with a BS degree.
In 1998, she earned a PhD in mathematics at the University of Pennsylvania in Philadelphia, Pennsylvania. Her thesis in Riemannian geometry was entitled Diameters of Spherical Alexandrov Spaces and Constant Curvature One Orbifolds and was supervised by Wolfgang Ziller
Career
Greenwald is a professor of mathematics at Appalachian State University and faculty affiliate of the gender, women's and sexuality studies program there. She has published numerous articles and books in the areas of Riemannian geometry, math education, and math in society. Greenwald has been trying to get young women in Girl Scouts interested in STEM. She and Appalachian State colleagues Amber Mellon and Jill Thomley have created a merit badge in mathematics to foster interest in mathematics. Greenwald has also created a series of short video interviews of women in STEM who were former Girl Scout members. This is a work in progress. Greenwald was elected in 2020 to serve as Member at Large of the Council of the American Mathematical Society during 2021-2024.
Honors
Greenwald was a 2005 winner of the Henry L. Alder Award for Distinguished Teaching by a Beginning College or University Mathematics Faculty Member of the Mathematical Association of America (MAA). In 2017, Greenwald was selected as a plenary speaker at spring southeast section meeting of the MAA at Clemson University in March 2018.
She received the AWM Service Awar |
https://en.wikipedia.org/wiki/Electronic%20organizer | An electronic organizer (or electric organizer) is a small calculator-sized computer, often with an built-in diary application and other functions such as an address book and calendar, replacing paper-based personal organizers. Typically, it has a small alphanumeric keypad and an LCD screen of one, two, or three lines. The electronic diary or organizer was invented by Indian businessman Satyan Pitroda in 1975, who is regarded as one of the earliest pioneers of hand-held computing because of his invention of the Electronic Diary in 1975.
They were very popular especially with businessmen during the 1990s, but because of the advent of palmtop PCs in the 1990s, personal digital assistants in the 2000s, and smartphones in the 2010s, all of which have a larger set of features, electronic organizers are mostly seen today for research purposes. One of the leading research topics being the study of how electronics can help people with mental disabilities use this type of equipment to aid their daily life. Electronic organizers have more recently been used to support people with Alzheimer's disease to have a visual representation of a schedule.
Casio digital diary
Casio digital diaries were produced by Casio in the early and mid 1990s, but have since been entirely superseded by Mobile Phones and PDAs.
Other electronic organizers
While Casio was a major role player in the field of electronic organizers there were many different ideas, patent requests, and manufacturers of electronic organizers. Rolodex, widely known for their index card holders in the 1980s, Sharp Electronics, mostly known for their printers and audio visual equipment, and lastly Royal electronics were all large contributors to the electronic organizer in its heyday.
Features
Telephone directory
Schedule keeper: Keep track of appointments.
Memo function: Store text data such as price lists, airplane schedules, and more.
To do list: Keep track of daily tasks, checking off items as you complete them.
|
https://en.wikipedia.org/wiki/Open-channel%20flow | In fluid mechanics and hydraulics, open-channel flow is a type of liquid flow within a conduit with a free surface, known as a channel. The other type of flow within a conduit is pipe flow. These two types of flow are similar in many ways but differ in one important respect: open-channel flow has a free surface, whereas pipe flow does not, resulting in flow dominated by gravity but not hydraulic pressure.
Classifications of flow
Open-channel flow can be classified and described in various ways based on the change in flow depth with respect to time and space. The fundamental types of flow dealt with in open-channel hydraulics are:
Time as the criterion
Steady flow
The depth of flow does not change over time, or if it can be assumed to be constant during the time interval under consideration.
Unsteady flow
The depth of flow does change with time.
Space as the criterion
Uniform flow
The depth of flow is the same at every section of the channel. Uniform flow can be steady or unsteady, depending on whether or not the depth changes with time, (although unsteady uniform flow is rare).
Varied flow
The depth of flow changes along the length of the channel. Varied flow technically may be either steady or unsteady. Varied flow can be further classified as either rapidly or gradually-varied:
Rapidly-varied flow
The depth changes abruptly over a comparatively short distance. Rapidly varied flow is known as a local phenomenon. Examples are the hydraulic jump and the hydraulic drop.
Gradually-varied flow
The depth changes over a long distance.
Continuous flow
The discharge is constant throughout the reach of the channel under consideration. This is often the case with a steady flow. This flow is considered continuous and therefore can be described using the continuity equation for continuous steady flow.
Spatially-varied flow
The discharge of a steady flow is non-uniform along a channel. This happens when water enters and/or leaves the channel along the cours |
https://en.wikipedia.org/wiki/Lois%20Privor-Dumm | Lois Privor-Dumm is an expert in the field of vaccine introduction. She is especially recognized for her work with new vaccine introduction, which has included strategies to accelerate access in low and middle-income countries, policy research, advocacy, communications and large country introduction.
She has worked with countries in all income groups and has leveraged her experiences in high and middle income countries to contribute to the significant recent improvements in access in low and low-middle income countries. She currently serves as the Director of Alliances & Information at the International Vaccine Access Center (IVAC) at the Johns Hopkins Bloomberg School of Public Health. Her team conducts advocacy and communications for child health, coordination of the World Pneumonia Day Coalition and working with large countries such as India and Nigeria to provide technical assistance in the form of advocacy and communications, evidence synthesis, stakeholder mapping and research to help countries develop strategies to address the barriers to decision making and implementation for new vaccines.
Her team has worked closely with a variety of stakeholders in India and Nigeria and is focused on building both high-level political and grassroots support. She is currently leading projects in India and Nigeria made possible through grants from the GAVI Alliance and Bill & Melinda Gates Foundation.
She is a member of the GAVI Large Country Task Team and the PDP Access Steering Committee and has worked on a number of access related projects dealing with economics and financing, supply, distribution and demand forecasting in addition to her work with advocacy, communications and policy.
Background and education
Ms. Privor-Dumm holds an International MBA (IMBA), formerly Masters in International Business (MIBS), from the University of South Carolina and completed her studies and internship in Brussels, Belgium. She completed her undergraduate studies at the University |
https://en.wikipedia.org/wiki/Bradytroph | A bradytroph is a strain of an organism that exhibits slow growth in the absence of an external source of a particular metabolite. This is usually due to a defect in an enzyme required in the metabolic pathway producing this chemical. Such defects are the result of mutations in the genes encoding these enzymes. As the organism can still produce small amounts of the chemical, the mutation is not lethal. In these bradytroph strains, rapid growth occurs when the chemical is present in the cell's growth media and the missing metabolite can be transported into the cell from the external environment. A bradytroph may also be referred to as a "leaky auxotroph".
The first usage of "bradytroph" was to describe Escherichia coli mutants partially defective in arginine biosynthesis. Among many other examples of bradytrophic strains of microorganisms are Bacillus subtilis strains with mutations affecting thiamine production and Saccharomyces cerevisiae strains with mutations that impair arginine biosynthesis.
See also
Autotroph
Auxotrophy |
https://en.wikipedia.org/wiki/Pinto%20Bean%20%28squirrel%29 | Pinto Bean was an eastern gray squirrel on the campus of the University of Illinois Urbana-Champaign that was renowned and named for its rare piebald pattern. It died in Champaign on October 8, 2022, presumably due to a motor vehicle collision. Pinto Bean has been called a "minor celebrity" and a "grassroots, unofficial mascot" for the university. During a home football game against Minnesota, a tribute to Pinto Bean was shown on the jumbotron at Memorial Stadium.
Pattern
An eastern gray squirrel, Pinto Bean was named for its distinctive mixture of gray fur with patches of unpigmented white fur, which resembled the appearance of pinto beans. According to Illinois Natural History Survey director Eric Shauber, this was the result of a rare genetic mutation that affected where melanin was distributed in the squirrel's body. Shauber said the mutation was rare enough to assume that there was only one such squirrel on campus.
Death and taxidermy
Pinto Bean was found dead on the side of Springfield Avenue in Champaign on October 8, 2022. Its cause of death was presumably a vehicular collision. News of its death quickly spread on the r/UIUC subreddit and other social media. One user, Champaign resident Clark Jackson, retrieved the squirrel's remains and delivered them to a taxidermist in Bloomington in an effort to preserve the squirrel.
As of March 27, 2023, Pinto Bean's taxidermied remains are on display at the Forbes Natural History Building on the south side of the university's campus.
Tributes
During Illinois's October 15, 2022, home football game against Minnesota, the jumbotron at Memorial Stadium displayed a tribute to Pinto Bean at halftime. The screen displayed an image of Pinto Bean, accompanied by the message: "RIP to Pinto Bean the Squirrel, forever in our hearts."
The Illini Wildlife and Conservation Club held a moment of silence in remembrance of Pinto Bean. Students and community members shared many tributes and eulogies on r/UIUC.
See also
Tomm |
https://en.wikipedia.org/wiki/Call%20signs%20in%20North%20America | Call signs are frequently still used by North American broadcast stations, in addition to amateur radio and other international radio stations that continue to identify by call signs worldwide. Each country has a different set of patterns for its own call signs. Call signs are allocated to ham radio stations in Barbados, Canada, Mexico and the United States.
Many countries have specific conventions for classifying call signs by transmitter characteristics and location. The call sign format for radio and television call signs follows a number of conventions. All call signs begin with a prefix assigned by the International Telecommunication Union. For example, the United States has been assigned the following prefixes: AAA–ALZ, K, N, W. For a complete list, see international call sign allocations.
Bermuda, Bahamas, and the Caribbean
Pertaining to their status as former or current colonies, all of the British West Indies islands shared the VS, ZB–ZJ, and ZN–ZO prefixes. The current, largely post-independence, allocation list is as follows:
Anguilla (in amateur radio VP2E prefix)
Antigua and Barbuda (uses V2 prefix)
Bahamas (has the C6 prefix)
Barbados (uses 8P)
Bermuda (also uses VS, in amateur radio normally VP9)
British Virgin Islands (for amateur radio uses VP2V)
Cayman Islands (ZF for amateur operation, ZF1 for Grand Cayman, ZF8 for Little Cayman and ZF9 for Cayman Brac islands. Visiting reciprocal for all islands is ZF2)
Dominica (Commonwealth of Dominica, uses J7)
Grenada (uses J3)
Jamaica (uses 6Y)
Montserrat (for amateur operation VP2M prefix)
St. Kitts and Nevis (uses V4)
St. Lucia (uses J6)
St. Vincent and the Grenadines (uses J8)
Turks and Caicos Islands (typically uses VP5)
Cuba
Cuba uses the prefixes CL–CM, CO, and T4, with district numbers from 0 to 9 for amateur operations.
Dominican Republic
The Dominican Republic uses the prefixes HI–HJ.
French West Indies
All of the French possessions share the prefix F. Further divisions that are |
https://en.wikipedia.org/wiki/Diet%20and%20longevity | The relationship between diet and longevity encompasses diverse research studies involving both humans and animals, requiring an analysis of complex mechanisms underlying the potential relationship between various dietary practices, health, and longevity.
As of 2021, there is no clinical evidence that any dietary practice contributes to longevity.
Fasting
The concept of fasting and longevity involves abstaining from food to decrease the incidence of diseases and increase lifespan. The use of fasting dates to the 5th century BC, as attributed to Greek physician Hippocrates who suggested that people with certain illnesses should abstain from food or drink as therapy.
Although health can be influenced by diet, including the type of foods consumed, the amount of calories ingested, and the duration and frequency of fasting periods, there is no good clinical evidence that fasting promotes longevity in humans, as of 2021.
Calorie restriction
Calorie restriction is a widely researched intervention to assess effects on aging, defined as a sustained reduction in dietary energy intake compared to the energy required for weight maintenance. To ensure metabolic homeostasis, the diet during calorie restriction must provide sufficient energy, micronutrients, and fiber. Some studies on rhesus monkeys showed that restricting calorie intake resulted in lifespan extension, while other animals studies did not detect a significant change.
According to preliminary research in humans, there is little evidence that calorie restriction affects lifespan. |
https://en.wikipedia.org/wiki/Transport%20by%20multiple-motor%20proteins | Transport by molecular motor proteins (Kinesin, Dynein and unconventional Myosin) is essential for cell functioning and survival. Studies of multiple motors are inspired by the fact that multiple motors are involved in many biological processes such as intra-cellular transport and mitosis. This increasing interest in modeling multiple motor transport is particularly due to improved understanding of single motor function. Several models have been proposed in recent year to understand the transport by multiple motors.
Models developed can be broadly divided into two categories (1) mean-field/steady state model and (2) stochastic model. The mean-field model is useful for describing transport by a large group of motors. In mean-field description, fluctuation in the forces that individual motors feel while pulling the cargo is ignored. In stochastic model, fluctuation in the forces that motors feel are not ignored. Steady-state/mean-field model is useful for modeling transport by a large group of motors whereas stochastic model is useful for modeling transport by few motors. |
https://en.wikipedia.org/wiki/River%20Raid | River Raid is a vertically scrolling shooter designed and programmed by Carol Shaw and published by Activision in 1982 for the Atari 2600 video game console. Over a million game cartridges were sold. Activision later ported the title to the Atari 5200, ColecoVision, and Intellivision consoles, as well as to the Commodore 64, IBM PCjr, MSX, ZX Spectrum, and Atari 8-bit family. Shaw did the Atari 8-bit and Atari 5200 ports herself.
Activision published a less successful sequel in 1988 without Shaw's involvement.
Gameplay
Viewed from a top-down perspective, the player flies a fighter jet over the River of No Return in a raid behind enemy lines. The player's jet can only move left and right—it cannot maneuver up and down the screen—but it can accelerate and decelerate. The player's jet crashes if it collides with the riverbank or an enemy craft, or if the jet runs out of fuel. Assuming fuel can be replenished, and if the player evades damage, gameplay is essentially unlimited.
The player scores points for shooting enemy tankers (30 points), helicopters (60 points), fuel depots (80 points), jets (100 points), and bridges (500 points). The jet refuels when it flies over a fuel depot. A bridge marks the end of a game level. Non-Atari 2600 ports of the game add hot air balloons that are worth 60 points when shot as well as tanks along the sides of the river that shoot at the player's jet.
Destroying bridges also serve as the game's checkpoints. If the player crashes the plane they will start their next jet at the last destroyed bridge.
Development
For its time, River Raid provided an inordinate amount of non-random, repeating terrain despite constrictive computer memory limits. For the Atari 2600 the game with its program code and graphics had to fit into a 4 KB ROM. The game program does not actually store the sequence of terrain and other objects. Instead, a procedural generation algorithm employing a linear-feedback shift register with a hard-coded starting value |
https://en.wikipedia.org/wiki/Lesser%20petrosal%20nerve | The lesser petrosal nerve (also known as the small superficial petrosal nerve) is the general visceral efferent (GVE) nerve conveying pre-ganglionic parasympathetic secretomotor fibers for the parotid gland from the tympanic plexus to the otic ganglion (where they synapse). It passes out of the tympanic cavity through the petrous part of the temporal bone into the middle cranial fossa of the cranial cavity, then exits the cranial cavity through its own canaliculus to reach the infratemporal fossa.
Cell bodies of the lesser petrosal nerve are situated in the inferior salivatory nucleus, and are conveyed first by the glossopharyngeal nerve (CN IX) and then by the tympanic nerve to the tympanic plexus.
Structure
Course
The nucleus of the lesser petrosal nerve is the inferior salivatory nucleus. The lesser petrosal nerve may be considered a continuation of the tympanic nerve.
After arising in the tympanic plexus, the lesser petrosal nerve passes anterior-ward, then through the hiatus for lesser petrosal nerve on the anterior surface of the petrous part of the temporal bone into the middle cranial fossa.
It runs across the floor of this fossa along a groove oriented in the direction the foramen ovale and situated parallel and anterolateral to the groove for the greater petrosal nerve and its groove.
It exits the skull via canaliculus innominatus and enters the infratemporal fossa. In the fossa, its fibres synapse at the otic ganglion. Post-ganglionic fibres then exit the ganglion to briefly travel along with the auriculotemporal nerve (a branch of the mandibular nerve (CN V3)) before entering the substance of the parotid gland.
The lesser petrosal nerve distributes its post-ganglionic parasympathetic (GVE) fibers to the parotid gland via the intraparotid plexus (or parotid plexus), the branches from the facial nerve in the parotid gland.
See also
Tympanic nerve
Glossopharyngeal Nerve, Overview of visceral motor component |
https://en.wikipedia.org/wiki/Carl%20S.%20Herz | Carl Samuel Herz (10 April 1930 – 1 May 1995) was an American-Canadian mathematician, specializing in harmonic analysis. His name is attached to the Herz–Schur multiplier. He held professorships at Cornell University and McGill University, where he was Peter Redpath Professor of Mathematics at the time of his death.
Education and career
Herz received his bachelor's degree from Cornell University in 1950 and continued on as a mathematics graduate student at Princeton University. There he received a Ph.D. under the supervision of Salomon Bochner in 1953 with the dissertation "Bessel Functions of Matrix Argument". According to Tom H. Koornwinder, Herz's dissertation (published in the Annals of Mathematics in May 1955) "was a pioneering paper in the field of special functions in several variables associated with Lie groups and with root systems." Herz returned to Cornell as an instructor, rising in rank to assistant professor in 1955, associate professor in 1958, and full professor in 1963. He remained at Cornell until 1969. During the academic year 1969–1970 he worked at Brandeis University and then in 1970 joined the faculty of McGill University as full professor, where he remained until his death in 1995. During the academic year 1962–1963 Herz was a Sloan Fellow at Université de Paris-Sud at Orsay, where he established close ties with mathematicians there that led to frequent academic visits at Orsay of a month or two each year. In the academic years 1957–1958 and 1976–1977 he was a visiting scholar at the Institute for Advanced Study.
Herz did mathematical research on spectral synthesis, positive-definite functions, Fourier transforms on convex sets, potential theory, Hp, and BMO. According to Nicholas Varopoulos, Herz made contributions "to the theory of symmetric spaces, Lie groups and the heat kernel on these; among other things he succeeded in classifying all faithful representations of Lie groups by contact transformations of a compact manifold."
In 1978 he |
https://en.wikipedia.org/wiki/Microbial%20genetics | Microbial genetics is a subject area within microbiology and genetic engineering. Microbial genetics studies microorganisms for different purposes. The microorganisms that are observed are bacteria, and archaea. Some fungi and protozoa are also subjects used to study in this field. The studies of microorganisms involve studies of genotype and expression system. Genotypes are the inherited compositions of an organism. (Austin, "Genotype," n.d.) Genetic Engineering is a field of work and study within microbial genetics. The usage of recombinant DNA technology is a process of this work. The process involves creating recombinant DNA molecules through manipulating a DNA sequence. That DNA created is then in contact with a host organism. Cloning is also an example of genetic engineering.
Since the discovery of microorganisms by Robert Hooke and Antoni van Leeuwenhoek during the period 1665-1885 they have been used to study many processes and have had applications in various areas of study in genetics.
For example: Microorganisms' rapid growth rates and short generation times are used by scientists to study evolution. Robert Hooke and Antoni van Leeuwenhoek discoveries involved depictions, observations, and descriptions of microorganisms. Mucor is the microfungus that Hooke presented and gave a depiction of. His contribution being, Mucor as the first microorganism to be illustrated. Antoni van Leeuwenhoek’s contribution to the microscopic protozoa and microscopic bacteria yielded to scientific observations and descriptions. These contributions were accomplished by a simple microscope, which led to the understanding of microbes today and continues to progress scientists understanding.
Microbial genetics also has applications in being able to study processes and pathways that are similar to those found in humans such as drug metabolism.
Role in understanding evolution
Microbial genetics can focus on Charles Darwin's work and scientists have continued to study his work a |
https://en.wikipedia.org/wiki/Octav%20Onicescu | Octav Onicescu (; August 20, 1892 – August 19, 1983) was a Romanian mathematician and a member of the Romanian Academy. Together with his student, Gheorghe Mihoc, he is considered to be the founder of the Romanian school of probability theory and statistics.
Biography
He was born in Botoșani, the son of Vlad Onicescu, from Ștefănești, Botoșani County, and Ana, from Oniceni, Neamț County. He graduated from the Botoșani A. T. Laurian High School in 1911 with a perfect average grade of 10. That same year, he entered the University of Bucharest, from where he graduated with degrees in mathematics and philosophy in 1913. From 1914 to 1916 he was a mathematics teacher at the military gymnasium of Dealu Monastery, near Târgoviște. From 1916 to 1918 he fought in World War I.
In 1919, Onicescu went to study geometry at the University of Rome, under the guidance of Tullio Levi-Civita. He earned his PhD in June, 1920 for a thesis titled Sopra gli spazi einsteiniani a gruppi continui di transformazione ("On Einstein manifolds and groups of continuous transformations"). The thesis, which dealt with problems in differential geometry related to Albert Einstein's theory of relativity, was defended in front of a jury of 11 mathematicians, including Levi-Civita, Vito Volterra, and Guido Castelnuovo.
In the fall of 1920 he went to Paris, where he gave talks in Jacques Hadamard's seminar at the Collège de France. While in Paris, he organized a seminar with other Romanian mathematicians, including Petre Sergescu, Șerban Gheorghiu, Alexandru Pantazi, and Șerban Coculescu.
In 1922, he returned to Bucharest, where he embarked on a 40-year-long university career. In 1924, he started teaching the first college-level probability theory course in Romania. From 1928 on, he was professor at the Faculty of Sciences of the University of Bucharest, and was appointed full professor in 1931. In 1930, he organized the School of Statistics and established an Institute of Calculus, serving as its d |
https://en.wikipedia.org/wiki/Lamb%E2%80%93Oseen%20vortex | In fluid dynamics, the Lamb–Oseen vortex models a line vortex that decays due to viscosity. This vortex is named after Horace Lamb and Carl Wilhelm Oseen.
Mathematical description
Oseen looked for a solution for the Navier–Stokes equations in cylindrical coordinates with velocity components of the form
where is the circulation of the vortex core. Navier-Stokes equations lead to
which, subject to the conditions that it is regular at and becomes unity as , leads to
where is the kinematic viscosity of the fluid. At , we have a potential vortex with concentrated vorticity at the axis; and this vorticity diffuses away as time passes.
The only non-zero vorticity component is in the direction, given by
The pressure field simply ensures the vortex rotates in the circumferential direction, providing the centripetal force
where ρ is the constant density
Generalized Oseen vortex
The generalized Oseen vortex may obtained by looking for solutions of the form
that leads to the equation
Self-similar solution exists for the coordinate , provided , where is a constant, in which case . The solution for may be written according to Rott (1958) as
where is an arbitrary constant. For , the classical Lamb–Oseen vortex is recovered. The case corresponds to the axisymmetric stagnation point flow, where is a constant. When , , a Burgers vortex is a obtained. For arbitrary , the solution becomes , where is an arbitrary constant. As , Burgers vortex is recovered.
See also
The Rankine vortex and Kaufmann (Scully) vortex are common simplified approximations for a viscous vortex. |
https://en.wikipedia.org/wiki/Somatic%20marker%20hypothesis | The somatic marker hypothesis, formulated by Antonio Damasio and associated researchers, proposes that emotional processes guide (or bias) behavior, particularly decision-making.
"Somatic markers" are feelings in the body that are associated with emotions, such as the association of rapid heartbeat with anxiety or of nausea with disgust. According to the hypothesis, somatic markers strongly influence subsequent decision-making. Within the brain, somatic markers are thought to be processed in the ventromedial prefrontal cortex (vmPFC) and the amygdala. The hypothesis has been tested in experiments using the Iowa gambling task.
Background
In economic theory, human decision-making is often modeled as being devoid of emotions, involving only logical reasoning based on cost-benefit calculations. In contrast, the somatic marker hypothesis proposes that emotions play a critical role in the ability to make fast, rational decisions in complex and uncertain situations.
Patients with frontal lobe damage, such as Phineas Gage, provided the first evidence that the frontal lobes were associated with decision-making. Frontal lobe damage, particularly to the vmPFC, results in impaired abilities to organize and plan behavior and learn from previous mistakes, without affecting intellect in terms of working memory, attention, and language comprehension and expression.
vmPFC patients also have difficulty expressing and experiencing appropriate emotions. This led Antonio Damasio to hypothesize that decision-making deficits following vmPFC damage result from the inability to use emotions to help guide future behavior based on past experiences. Consequently, vmPFC damage forces those affected to rely on slow and laborious cost-benefit analyses for every given choice situation.
Antonio Damasio
Antonio Damasio () is a Portuguese-American neuroscientist. He is currently the David Dornsife Professor of Neuroscience, Psychology and Philosophy at the University of Southern California and |
https://en.wikipedia.org/wiki/The%20Journal%20of%20Molecular%20Diagnostics | The Journal of Molecular Diagnostics is a peer-reviewed medical journal covering research on molecular biological applications to diagnostics (molecular diagnostics). It is published by Elsevier on behalf of the American Society for Investigative Pathology and the Association for Molecular Pathology. The editor-in-chief is Ronald M. Przygodzki, MD (US Department of Veterans Affairs). The journal was established in 1999 as The American Journal of Pathology, Part B, with Nelson Fausto (University of Washington) as founding editor.
According to the Journal Citation Reports, the journal has a 2021 impact factor of 5.341.
Editors
The following persons have been editors-in-chief of the journal: |
https://en.wikipedia.org/wiki/Variegation | Variegation is the appearance of differently coloured zones in the leaves and sometimes the stems and fruit of plants. Species with variegated individuals are sometimes found in the understory of tropical rainforests, and this habitat is the source of a number of variegated houseplants. Variegation is caused by mutations that affect chlorophyll production or by viruses, such as mosaic viruses, which have been studied by scientists. The striking look of variegated plants is desired by many gardeners, and some have deliberately tried to induce it for aesthetic purposes. There are a number of gardening books about variegated plants, and some gardening societies specialize in them.
The term is also sometimes used to refer to colour zonation in flowers, minerals, and the skin, fur, feathers or scales of animals.
Causes
Chimeral
Plants that are chimeras contain tissues with more than one genotype. A variegated chimera contains some tissues that produce chlorophyll and other tissues which do not. Because the variegation is due to the presence of two kinds of plant tissue, propagating the plant must be by a vegetative method of propagation that preserves both types of tissue in relation to each other. Typically, stem cuttings, bud and stem grafting, and other propagation methods that results in growth from leaf axil buds will preserve variegation. Cuttings with complete variegation may be difficult, if not impossible, to propagate. Root cuttings will not usually preserve variegation, since the new stem tissue is derived from a particular tissue type within the root.
Some variegation is due to visual effects caused by reflection of light from the leaf surface. This can happen when an air layer is located just under the epidermis resulting in a white or silvery reflection. It is sometimes called blister variegation. Pilea cadierei (aluminum plant) is an example of a house plant that shows this effect. Leaves of most Cyclamen species show such patterned variegation, var |
https://en.wikipedia.org/wiki/Proof%20without%20words | In mathematics, a proof without words (or visual proof) is an illustration of an identity or mathematical statement which can be demonstrated as self-evident by a diagram without any accompanying explanatory text. Such proofs can be considered more elegant than formal or mathematically rigorous proofs due to their self-evident nature. When the diagram demonstrates a particular case of a general statement, to be a proof, it must be generalisable.
A proof without words is not the same as a mathematical proof, because it omits the details of the logical argument it illustrates. However, it can provide valuable intuitions to the viewer that can help them formulate or better understand a true proof.
Examples
Sum of odd numbers
The statement that the sum of all positive odd numbers up to 2n − 1 is a perfect square—more specifically, the perfect square n2—can be demonstrated by a proof without words.
In one corner of a grid, a single block represents 1, the first square. That can be wrapped on two sides by a strip of three blocks (the next odd number) to make a 2 × 2 block: 4, the second square. Adding a further five blocks makes a 3 × 3 block: 9, the third square. This process can be continued indefinitely.
Pythagorean theorem
The Pythagorean theorem that can be proven without words.
One method of doing so is to visualise a larger square of sides , with four right-angled triangles of sides , and in its corners, such that the space in the middle is a diagonal square with an area of . The four triangles can be rearranged within the larger square to split its unused space into two squares of and .
Jensen's inequality
Jensen's inequality can also be proven graphically. A dashed curve along the X axis is the hypothetical distribution of X, while a dashed curve along the Y axis is the corresponding distribution of Y values. The convex mapping Y(X) increasingly "stretches" the distribution for increasing values of X.
Usage
Mathematics Magazine and the College Math |
https://en.wikipedia.org/wiki/NDOR1 | NADPH-dependent diflavin oxidoreductase 1 is an enzyme that in humans is encoded by the NDOR1 gene. |
https://en.wikipedia.org/wiki/Thread%20safety | Thread safety is a computer programming concept applicable to multi-threaded code. Thread-safe code only manipulates shared data structures in a manner that ensures that all threads behave properly and fulfill their design specifications without unintended interaction. There are various strategies for making thread-safe data structures.
A program may execute code in several threads simultaneously in a shared address space where each of those threads has access to virtually all of the memory of every other thread. Thread safety is a property that allows code to run in multithreaded environments by re-establishing some of the correspondences between the actual flow of control and the text of the program, by means of synchronization.
Levels of thread safety
Software libraries can provide certain thread-safety guarantees. For example, concurrent reads might be guaranteed to be thread-safe, but concurrent writes might not be. Whether a program using such a library is thread-safe depends on whether it uses the library in a manner consistent with those guarantees.
Different vendors use slightly different terminology for thread-safety:
Thread safe: Implementation is guaranteed to be free of race conditions when accessed by multiple threads simultaneously.
Conditionally safe: Different threads can access different objects simultaneously, and access to shared data is protected from race conditions.
Not thread safe: Data structures should not be accessed simultaneously by different threads.
Thread safety guarantees usually also include design steps to prevent or limit the risk of different forms of deadlocks, as well as optimizations to maximize concurrent performance. However, deadlock-free guarantees cannot always be given, since deadlocks can be caused by callbacks and violation of architectural layering independent of the library itself.
Implementation approaches
Below we discuss two classes of approaches for avoiding race conditions to achieve thread-safety.
The fi |
https://en.wikipedia.org/wiki/Operant%20conditioning%20chamber | An operant conditioning chamber (also known as a Skinner box) is a laboratory apparatus used to study animal behavior. The operant conditioning chamber was created by B. F. Skinner while he was a graduate student at Harvard University. The chamber can be used to study both operant conditioning and classical conditioning.
Skinner created the operant conditioning chamber as a variation of the puzzle box originally created by Edward Thorndike. While Skinner's early studies were done using rats, he later moved on to study pigeons. The operant conditioning chamber may be used to observe or manipulate behaviour. An animal is placed in the box where it must learn to activate levers or respond to light or sound stimuli for reward. The reward may be food or the removal of noxious stimuli such as a loud alarm. The chamber is used to test specific hypotheses in a controlled setting.
Name
Skinner was noted to have expressed his distaste for becoming an eponym. It is believed that Clark Hull and his Yale students coined the expression "Skinner box". Skinner stated he did not use the term himself, and went so far as to ask Howard Hunt to use "lever box" instead of "Skinner box" in a published document.
History
In 1898, American psychologist, Edward Thorndike proposed the 'law of effect', which formed the basis of operant conditioning. Thorndike conducted experiments to discover how cats learn new behaviors. His work involved monitoring cats as they attempted to escape from puzzle boxes. The puzzle box trapped the animals until they moved a lever or performed an action which triggered their release. Thorndike ran several trials and recorded the time it took for them to perform the actions necessary to escape. He discovered that the cats seemed to learn from a trial-and-error process rather than insightful inspections of their environment. The animals learned that their actions led to an effect, the type of effect influenced whether the behavior would be repeated. Thorndike's |
https://en.wikipedia.org/wiki/SciDB | SciDB is a column-oriented database management system (DBMS) designed for multidimensional data management and analytics common to scientific, geospatial, financial, and industrial applications. It is developed by Paradigm4 and co-created by Michael Stonebraker.
History
Stonebraker claims that arrays are 100 times faster in SciDB than in a relational DBMS on a class of problems. It is swapping rows and columns for mathematical arrays that put fewer restrictions on the data and can work in any number of dimensions unlike the conventionally widely used relational database management system model, in which each relation supports only one dimension of records.
A 2011 conference presentation on SciDB promoted it as "not Hadoop".
Marilyn Matz became chief executive Paradigm4 in 2014.
See also
Comparison of object database management systems
Comparison of structured storage software |
https://en.wikipedia.org/wiki/Oncogenic%20retroviridae%20protein | Oncogenic retroviridae proteins are retroviral proteins that have the ability to transform cells. They can induce sarcomas, leukaemias, lymphomas, and mammary carcinomas. These include the gag-onc fusion protein, rex, tax, v-fms, ras, v-myc, v-src, v-akt, v-cbl, v-crk, v-maf, v-abl, v-erbA, v-erbB, v-fos, v-mos, v-myb, v-raf, v-rel, and v-sis. The "v" prefix indicates viral genes which once originated as similarly named genes of the host species, but have since been altered through independent evolution as retroviral components. Not all retroviral proteins are oncogenic. The phrase was introduced as a MeSH term in 1990, under which over 6000 primary scientific publications are indexed.
See also
Oncogenic |
https://en.wikipedia.org/wiki/Buffer%20overflow | In programming and information security, a buffer overflow or buffer overrun is an anomaly whereby a program writes data to a buffer beyond the buffer's allocated memory, overwriting adjacent memory locations.
Buffers are areas of memory set aside to hold data, often while moving it from one section of a program to another, or between programs. Buffer overflows can often be triggered by malformed inputs; if one assumes all inputs will be smaller than a certain size and the buffer is created to be that size, then an anomalous transaction that produces more data could cause it to write past the end of the buffer. If this overwrites adjacent data or executable code, this may result in erratic program behavior, including memory access errors, incorrect results, and crashes.
Exploiting the behavior of a buffer overflow is a well-known security exploit. On many systems, the memory layout of a program, or the system as a whole, is well defined. By sending in data designed to cause a buffer overflow, it is possible to write into areas known to hold executable code and replace it with malicious code, or to selectively overwrite data pertaining to the program's state, therefore causing behavior that was not intended by the original programmer. Buffers are widespread in operating system (OS) code, so it is possible to make attacks that perform privilege escalation and gain unlimited access to the computer's resources. The famed Morris worm in 1988 used this as one of its attack techniques.
Programming languages commonly associated with buffer overflows include C and C++, which provide no built-in protection against accessing or overwriting data in any part of memory and do not automatically check that data written to an array (the built-in buffer type) is within the boundaries of that array. Bounds checking can prevent buffer overflows, but requires additional code and processing time. Modern operating systems use a variety of techniques to combat malicious buffer overflows |
https://en.wikipedia.org/wiki/Surface%20metrology | Surface metrology is the measurement of small-scale features on surfaces, and is a branch of metrology. Surface primary form, surface fractality, and surface finish (including surface roughness) are the parameters most commonly associated with the field. It is important to many disciplines and is mostly known for the machining of precision parts and assemblies which contain mating surfaces or which must operate with high internal pressures.
Surface finish may be measured in two ways: contact and non-contact methods. Contact methods involve dragging a measurement stylus across the surface; these instruments are called profilometers. Non-contact methods include: interferometry, digital holography, confocal microscopy, focus variation, structured light, electrical capacitance, electron microscopy, photogrammetry and non-contact profilometers.
Overview
The most common method is to use a diamond stylus profilometer. The stylus is run perpendicular to the lay of the surface. The probe usually traces along a straight line on a flat surface or in a circular arc around a cylindrical surface. The length of the path that it traces is called the measurement length. The wavelength of the lowest frequency filter that will be used to analyze the data is usually defined as the sampling length. Most standards recommend that the measurement length should be at least seven times longer than the sampling length, and according to the Nyquist–Shannon sampling theorem it should be at least two times longer than the wavelength of interesting features. The assessment length or evaluation length is the length of data that will be used for analysis. Commonly one sampling length is discarded from each end of the measurement length. 3D measurements can be made with a profilometer by scanning over a 2D area on the surface.
The disadvantage of a profilometer is that it is not accurate when the size of the features of the surface are close to the same size as the stylus. Another disadvantage is |
https://en.wikipedia.org/wiki/Ventriculitis | Ventriculitis is the inflammation of the ventricles in the brain. The ventricles are responsible for containing and circulating cerebrospinal fluid throughout the brain. Ventriculitis is caused by infection of the ventricles, leading to swelling and inflammation. This is especially prevalent in patients with external ventricular drains and intraventricular stents. Ventriculitis can cause a wide variety of short-term symptoms and long-term side effects ranging from headaches and dizziness to unconsciousness and death if not treated early. It is treated with some appropriate combination of antibiotics in order to rid the patient of the underlying infection. Much of the current research involving ventriculitis focuses specifically around defining the disease and what causes it. This will allow for much more advancement in the subject. There is also a lot of attention being paid to possible treatments and prevention methods to help make this disease even less prevalent and dangerous.
Signs and symptoms
There is great deal of variety in the symptoms associated with ventriculitis. The symptoms vary based on a number of different factors including severity of inflammation, underlying cause, and the individual patient.
Patients often present with headaches, painful cranial pressure, and neck pain early in the progression of the disease. Patients with a more advanced infection have been known to complain of many neurological effects such as dizziness, vertigo, confusion, and slurred speech. Very advanced cases can lead to mental instability, nausea, vomiting, rigors, and temporary loss of consciousness. Many patients with ventriculitis also experience some degree of hydrocephalus, which is the buildup of cerebrospinal fluid due to the inability of the ventricles to reabsorb and correctly circulate the fluid. Brain abscess is another common disorder resulting from the inflammation. If left untreated, ventriculitis can lead to serious inhibition of mental function and even |
https://en.wikipedia.org/wiki/Cantharellus%20flavus | Cantharellus flavus is a species of fungus in the genus Cantharellus. Found in North America, it was described in 2013. |
https://en.wikipedia.org/wiki/Mitochondrial%20fusion | Mitochondria are dynamic organelles with the ability to fuse and divide (fission), forming constantly changing tubular networks in most eukaryotic cells. These mitochondrial dynamics, first observed over a hundred years ago are important for the health of the cell, and defects in dynamics lead to genetic disorders. Through fusion, mitochondria can overcome the dangerous consequences of genetic malfunction. The process of mitochondrial fusion involves a variety of proteins that assist the cell throughout the series of events that form this process.
Process overview
When cells experience metabolic or environmental stresses, mitochondrial fusion and fission work to maintain functional mitochondria. An increase in fusion activity leads to mitochondrial elongation, whereas an increase in fission activity results in mitochondrial fragmentation. The components of this process can influence programmed cell death and lead to neurodegenerative disorders such as Parkinson's disease. Such cell death can be caused by disruptions in the process of either fusion or fission.
The shapes of mitochondria in cells are continually changing via a combination of fission, fusion, and motility. Specifically, fusion assists in modifying stress by integrating the contents of slightly damaged mitochondria as a form of complementation. By enabling genetic complementation, fusion of the mitochondria allows for two mitochondrial genomes with different defects within the same organelle to individually encode what the other lacks. In doing so, these mitochondrial genomes generate all of the necessary components for a functional mitochondrion.
With mitochondrial fission
The combined effects of continuous fusion and fission give rise to mitochondrial networks. The mechanisms of mitochondrial fusion and fission are regulated by proteolysis and posttranslational modifications. The actions of fission, fusion and motility cause the shapes of these double membrane bound subcellular organelles we know |
https://en.wikipedia.org/wiki/Hard%20inheritance | Hard inheritance was a model of heredity that explicitly excludes any acquired characteristics, such as of Lamarckism. It is the exact opposite of soft inheritance, coined by Ernst Mayr to contrast ideas about inheritance.
Hard inheritance states that characteristics of an organism's offspring (passed on through DNA) will not be affected by the actions that the parental organism performs during its lifetime. For example: a medieval blacksmith who uses only his right arm to forge steel will not sire a son with a stronger right arm than left because the blacksmith's actions do not alter his genetic code. Inheritance due to usage and non-usage is excluded. Inheritance works as described in the modern synthesis of evolutionary biology.
The existence of inherited epigenetic variants has led to renewed interest in soft inheritance. |
https://en.wikipedia.org/wiki/Capital%20recovery%20factor | A capital recovery factor is the ratio of a constant annuity to the present value of receiving that annuity for a given length of time. Using an interest rate i, the capital recovery factor is:
where is the number of annuities received.
This is related to the annuity formula, which gives the present value in terms of the annuity, the interest rate, and the number of annuities.
If , the reduces to . Also, as , the .
Example
With an interest rate of i = 10%, and n = 10 years, the CRF = 0.163. This means that a loan of $1,000 at 10% interest will be paid back with 10 annual payments of $163.
Another reading that can be obtained is that the net present value of 10 annual payments of $163 at 10% discount rate is $1,000. |
https://en.wikipedia.org/wiki/Augmented%20learning | Augmented learning is an on-demand learning technique where the environment adapts to the learner. By providing remediation on-demand, learners can gain greater understanding of a topic while stimulating discovery and learning.
Technologies incorporating rich media and interaction have demonstrated the educational potential that scholars, teachers and students are embracing. Instead of focusing on memorization, the learner experiences an adaptive learning experience based upon the current context. The augmented content can be dynamically tailored to the learner's natural environment by displaying text, images, video or even playing audio (music or speech). This additional information is commonly shown in a pop-up window for computer-based environments.
Most implementations of augmented learning are forms of e-learning. In desktop computing environments, the learner receives supplemental, contextual information through an on-screen, pop-up window, toolbar or sidebar. As the user navigates a website, e-mail or document, the learner associates the supplemental information with the key text selected by a mouse, touch or other input device. In mobile environments, augmented learning has also been deployed on tablets and smartphones.
Augmented learning is often used by corporate learning and development providers to teach innovative thinking and leadership skills by emphasizing “learning-by-doing”. Participants are required to apply the skills gained from e-learning platforms to real life examples. Data is used to create a personalized learning program for each participant, providing supplemental information and remediation.
Augmented learning is closely related to augmented intelligence (intelligence amplification) and augmented reality. Augmented intelligence applies information processing capabilities to extend the processing capabilities of the human mind through distributed cognition. Augmented intelligence provides extra support for autonomous intelligence and h |
https://en.wikipedia.org/wiki/Veridicality | In linguistics, veridicality (from Latin "truthfully said") is a semantic or grammatical assertion of the truth of an utterance.
Definition
Merriam-Webster defines "veridical" as truthful, veracious and non illusory. It stems from the Latin "veridicus", composed of Latin verus, meaning "true", and dicere, which means "to say".
For example, the statement "Paul saw a snake" asserts the truthfulness of the claim, while "Paul did see a snake" is an even stronger assertion.
The formal definition of veridicality views the context as a propositional operator (Giannakidou 1998).
A propositional operator F is veridical iff Fp entails p, that is, Fp → p; otherwise F is nonveridical.
Additionally, a nonveridical operator F is antiveridical iff Fp entails not p, that is, Fp → ¬p.
For temporal and aspectual operators, the definition of veridicality is somewhat more complex:
For operators relative to instants of time: Let F be a temporal or aspectual operator, and t an instant of time.
F is veridical iff for Fp to be true at time t, p must be true at a (contextually relevant) time ≤ t; otherwise F is nonveridical.
A nonveridical operator F is antiveridical iff for Fp to be true at time t, ¬p must be true at a (contextually relevant) time ≤ t.
For operators relative to intervals of time: Let F be a temporal or aspectual operator, and t an interval of time.
F is veridical iff for Fp to be true of t, p must be true of all (contextually relevant) ⊆ t; otherwise F is nonveridical.
A nonveridical operator F is antiveridical iff for Fp to be true of t, ¬p must be true of all (contextually relevant) ⊆ t.
Nonveridical operators
Negation is veridical, though of opposite polarity, sometimes called antiveridical: "Paul didn't see a snake" asserts that the statement "Paul saw a snake" is false. In English, non-indicative moods or irrealis moods are frequently used in a nonveridical sense: "Paul may have seen a snake" and "Paul would have seen a snake" do not assert that P |
https://en.wikipedia.org/wiki/Phonological%20Awareness%20for%20Literacy | The Phonological Awareness for Literacy (PAL) Program (Burrows, Allison, Barnett, and Savina, 2007) is a commercial literacy therapy program for use by speech therapists designed to improve phonological awareness skills required for literacy in children aged 8 – 12. It aims to create and strengthen awareness of the relationship between phonological awareness skills to reading and writing.
Theoretical foundations
Adapted from Auditory Discrimination in Depth (Lindamood & Lindamood, 1975), which is now known as the Lindamood Phoneme Sequencing (LiPS) Program.
Intervention description
The PAL introduces identification, segmentation, blending and manipulation of speech sounds in syllables. It does not encourage reading using the whole-word approach instead teaching children to break written words up into individual graphemes and matching letters with their corresponding phonemes before reassembling the phonemes back into words to read.
Key skills taught
Developing an awareness of linguistic terms: Checks child's understanding of literacy terminology used and teaches the child how to talk about language (metalinguistic skills).
Sound–symbol association: Determines child's knowledge of how letters and sounds correspond, and that can be several representations of each sound.
Block representation of Consonant or vowel sequences: This component facilitates the child's ability to segment words into individual phonemes through developing auditory analysis skills. A single block represents an individual sound, and a row of blocks represent a string of sounds; so that the number of blocks directly correlates to the number of sounds in the sequence.
Block representation of syllables: Once the child understands that syllables consist of sounds, they then have to count the number of sounds, the order and distinguish between phonetic features. N.B. all block representation tasks deal only with non-words; this is to prevent the child from using pre-learned spelling pattern |
https://en.wikipedia.org/wiki/Oak%20Investment%20Partners | Oak Investment Partners is a private equity firm focusing on venture capital investments in companies developing communications systems, information technology, new Internet media, healthcare services and retail.
History
The firm, founded in 1978, is based in Greenwich, Connecticut, with offices in Norwalk, Connecticut, Minneapolis and Palo Alto, California. Since inception, Oak had invested in more than 480 companies and had raised more than $8.4 billion in investor commitments across 12 private equity funds. Ann Lamont is a founder and managing partner.
In May 2006, Oak raised its 12th fund, at $2.56 billion, reportedly the largest venture capital fund ever raised.
In 2015, Indian-born employee Iftikar Ahmed was sued by the U.S. Securities and Exchange Commission on suspicion of stealing US$65 million from the firm. Ahmed was believed to have fled to India. In August 2015, Fortune reported that Mr. Ahmed had been detained in an Indian prison from May 22 until July 23 and that his passport had been confiscated. |
https://en.wikipedia.org/wiki/Kouteck%C3%BD%E2%80%93Levich%20equation | The Koutecký–Levich equation models the measured electric current at an electrode from an electrochemical reaction in relation to the kinetic activity and the mass transport of reactants.
The Koutecký–Levich equation can be written as:
where
im is the measured current (A).
iK is the kinetic current (A) from the electrochemical reactions.
iMT is the mass transport current (A).
Note the similarity of this equation to the conductance of an electrical circuits in parallel.
The Koutecký–Levich equation is also commonly expressed as:
The kinetic current (iK) can be modeled by the Butler-Volmer Equation and is characterized by being potential dependent. On the other hand, the mass transport current (iMT) depends on the particular electrochemical setup and amount of stirring.
Koutecký–Levich plot
In the case a rotating disk electrode setup is used and the electrode is flat and smooth, the iMT can modeled using the Levich equation. Inserted in the Koutecký–Levich equation, we get:
where:
BL is the Levich Constant.
ω is the angular rotation rate of the electrode (rad/s)
From an experimental data set where the current is measured at different rotation rates, it is possible to extract the kinetic current from a so-called Koutecký–Levich plot. In a Koutecký–Levich plot the inverse measured current is plotted versus the inverse square root of the rotation rate. This will linearize the data set and the inverse of the kinetic current can be obtained by extrapolating the line to the ordinate. This y-intercept corresponds to taking the rotation rate up to infinity, where the reaction is not mass-transport limited. Koutecký–Levich analysis is therefore used to determine the kinetic constants of the reaction such as the kinetic constant and the symmetry factor . |
https://en.wikipedia.org/wiki/Plant%20development | Important structures in plant development are buds, shoots, roots, leaves, and flowers; plants produce these tissues and structures throughout their life from meristems located at the tips of organs, or between mature tissues. Thus, a living plant always has embryonic tissues. By contrast, an animal embryo will very early produce all of the body parts that it will ever have in its life. When the animal is born (or hatches from its egg), it has all its body parts and from that point will only grow larger and more mature. However, both plants and animals pass through a phylotypic stage that evolved independently and that causes a developmental constraint limiting morphological diversification.
According to plant physiologist A. Carl Leopold, the properties of organization seen in a plant are emergent properties which are more than the sum of the individual parts. "The assembly of these tissues and functions into an integrated multicellular organism yields not only the characteristics of the separate parts and processes but also quite a new set of characteristics which would not have been predictable on the basis of examination of the separate parts."
Growth
A vascular plant begins from a single celled zygote, formed by fertilisation of an egg cell by a sperm cell. From that point, it begins to divide to form a plant embryo through the process of embryogenesis. As this happens, the resulting cells will organize so that one end becomes the first root while the other end forms the tip of the shoot. In seed plants, the embryo will develop one or more "seed leaves" (cotyledons). By the end of embryogenesis, the young plant will have all the parts necessary to begin in its life.
Once the embryo germinates from its seed or parent plant, it begins to produce additional organs (leaves, stems, and roots) through the process of organogenesis. New roots grow from root meristems located at the tip of the root, and new stems and leaves grow from shoot meristems located at the |
https://en.wikipedia.org/wiki/Fedora%20Linux%20release%20history | Fedora Linux is a popular Linux distribution developed by the Fedora Project. Fedora attempts to maintain a six-month release schedule, offering new versions in May and November, although some releases have experienced minor delays.
Release history
Fedora Core 1
Fedora Core 1 was the first version of Fedora and was released on November 6, 2003. It was codenamed Yarrow. Fedora Core 1 was based on Red Hat Linux 9.
Some of the features in Fedora Core 1 included:
Version 2.4.19 of the Linux kernel;
Version 2.4 of the GNOME Desktop Environment (GNOME);
Version 3.1 of the K Desktop Environment (KDE).
Fedora Core 2
Fedora Core 2 was released on May 18, 2004, codenamed Tettnang.
Some of the new features in Fedora Core 2 included:
Version 2.6 of the Linux kernel;
Version 2.6 of the GNOME Desktop Environment (GNOME);
Version 3.2 of the K Desktop Environment (KDE);
Security-Enhanced Linux (SELinux);
New X.org.
SELinux was disabled by default due to concerns that it radically altered the way that Fedora Core ran. XFree86 was replaced by the newer X.org, a merger of the previous official X11R6 release, which additionally included a number of updates to Xrender, Xft, Xcursor, fontconfig libraries, and other significant improvements.
Fedora Core 3
Fedora Core 3 was released on November 8, 2004, codenamed Heidelberg.
Some of the new features in Fedora Core 3 included:
The Mozilla Firefox web browser;
Support for Indic scripts;
GNU GRUB boot loader;
Version 2.8 of the GNOME desktop environment (GNOME);
Version 3.3 of the K Desktop Environment (KDE);
New Fedora Extras repository;
SELinux enabled by default.
This release deprecated the LILO boot loader in favor of GNU GRUB. Security-Enhanced Linux (SELinux) now had a new targeted policy, which was less strict than the policy used in Fedora Core 2.
Fedora Core 4
Fedora Core 4 was released on June 13, 2005, with the codename Stentz. It shipped with Linux 2.6.11, KDE 3.4 and GNOME 2.10. This version introdu |
https://en.wikipedia.org/wiki/Dual%20bundle | In mathematics, the dual bundle is an operation on vector bundles extending the operation of duality for vector spaces.
Definition
The dual bundle of a vector bundle is the vector bundle whose fibers are the dual spaces to the fibers of .
Equivalently, can be defined as the Hom bundle that is, the vector bundle of morphisms from to the trivial line bundle
Constructions and examples
Given a local trivialization of with transition functions a local trivialization of is given by the same open cover of with transition functions (the inverse of the transpose). The dual bundle is then constructed using the fiber bundle construction theorem. As particular cases:
The dual bundle of an associated bundle is the bundle associated to the dual representation of the structure group.
The dual bundle of the tangent bundle of a differentiable manifold is its cotangent bundle.
Properties
If the base space is paracompact and Hausdorff then a real, finite-rank vector bundle and its dual are isomorphic as vector bundles. However, just as for vector spaces, there is no natural choice of isomorphism unless is equipped with an inner product.
This is not true in the case of complex vector bundles: for example, the tautological line bundle over the Riemann sphere is not isomorphic to its dual. The dual of a complex vector bundle is indeed isomorphic to the conjugate bundle but the choice of isomorphism is non-canonical unless is equipped with a hermitian product.
The Hom bundle of two vector bundles is canonically isomorphic to the tensor product bundle
Given a morphism of vector bundles over the same space, there is a morphism between their dual bundles (in the converse order), defined fibrewise as the transpose of each linear map Accordingly, the dual bundle operation defines a contravariant functor from the category of vector bundles and their morphisms to itself. |
https://en.wikipedia.org/wiki/Burkholderia%20virus%20phiE122 | Burkholderia virus phiE122 is a bacteriophage (a virus that infects bacteria) of the family Myoviridae, genus Tigrvirus. Its genetic structure corresponds to the class I of the Baltimore classification: dsDNA, being a DNA virus. |
https://en.wikipedia.org/wiki/Amplitude%20modulation%20signalling%20system | The amplitude modulation signalling system (AMSS or the AM signalling system) is a digital system for adding low bit rate information to an analogue amplitude modulated broadcast signal in the same manner as the Radio Data System (RDS) for frequency modulated (FM) broadcast signals.
This system has been standardized in March 2006 by ETSI (TS 102 386) as an extension to the Digital Radio Mondiale (DRM) system.
Broadcasting
AMSS data are broadcast from the following transmitters:
LW
RTL France: 234 kHz
SW
BBC World Service: 15.575 MHz
Formerly it was also used by:
MW
Truckradio 531 kHz
BBC World Service: 648 kHz
Deutschlandradio Kultur: 990 kHz
External links
ETSI TS 102 386 V1.2.1 (2006-03) directly from ETSI Publications Download Area (account or free registration required)
Radio technology
Broadcast engineering
2006 introductions
2006 establishments |
https://en.wikipedia.org/wiki/Object%20composition | In computer science, object composition and object aggregation are closely related ways to combine objects or data types into more complex ones. In conversation the distinction between composition and aggregation is often ignored. Common kinds of compositions are objects used in object-oriented programming, tagged unions, sets, sequences, and various graph structures. Object compositions relate to, but are not the same as, data structures.
Object composition refers to the logical or conceptual structure of the information, not the implementation or physical data structure used to represent it. For example, a sequence differs from a set because (among other things) the order of the composed items matters for the former but not the latter. Data structures such as arrays, linked lists, hash tables, and many others can be used to implement either of them. Perhaps confusingly, some of the same terms are used for both data structures and composites. For example, "binary tree" can refer to either: as a data structure it is a means of accessing a linear sequence of items, and the actual positions of items in the tree are irrelevant (the tree can be internally rearranged however one likes, without changing its meaning). However, as an object composition, the positions are relevant, and changing them would change the meaning (as for example in cladograms).
Programming technique
Object-oriented programming is based on objects to encapsulate data and behavior. It uses two main techniques for assembling and composing functionality into more complex ones, sub-typing and object composition. Object composition is about combining objects within compound objects, and at the same time, ensuring the encapsulation of each object by using their well-defined interface without visibility of their internals. In this regard, object composition differs from data structures, which do not enforce encapsulation.
Object composition may also be about a group of multiple related objects, s |
https://en.wikipedia.org/wiki/Duffing%20equation | The Duffing equation (or Duffing oscillator), named after Georg Duffing (1861–1944), is a non-linear second-order differential equation used to model certain damped and driven oscillators. The equation is given by
where the (unknown) function is the displacement at time , is the first derivative of with respect to time, i.e. velocity, and is the second time-derivative of i.e. acceleration. The numbers and are given constants.
The equation describes the motion of a damped oscillator with a more complex potential than in simple harmonic motion (which corresponds to the case ); in physical terms, it models, for example, an elastic pendulum whose spring's stiffness does not exactly obey Hooke's law.
The Duffing equation is an example of a dynamical system that exhibits chaotic behavior. Moreover, the Duffing system presents in the frequency response the jump resonance phenomenon that is a sort of frequency hysteresis behaviour.
Parameters
The parameters in the above equation are:
controls the amount of damping,
controls the linear stiffness,
controls the amount of non-linearity in the restoring force; if the Duffing equation describes a damped and driven simple harmonic oscillator,
is the amplitude of the periodic driving force; if the system is without a driving force, and
is the angular frequency of the periodic driving force.
The Duffing equation can be seen as describing the oscillations of a mass attached to a nonlinear spring and a linear damper. The restoring force provided by the nonlinear spring is then
When and the spring is called a hardening spring. Conversely, for it is a softening spring (still with ). Consequently, the adjectives hardening and softening are used with respect to the Duffing equation in general, dependent on the values of (and ).
The number of parameters in the Duffing equation can be reduced by two through scaling (in accord with the Buckingham π theorem), e.g. the excursion and time can be scaled as: and a |
https://en.wikipedia.org/wiki/SWIG | The Simplified Wrapper and Interface Generator (SWIG) is an open-source software tool used to connect computer programs or libraries written in C or C++ with scripting languages such as Lua, Perl, PHP, Python, R, Ruby, Tcl, and other languages like C#, Java, JavaScript, Go, D, OCaml, Octave, Scilab and Scheme. Output can also be in the form of XML.
Function
The aim is to allow the calling of native functions (that were written in C or C++) by other programming languages, passing complex data types to those functions, keeping memory from being inappropriately freed, inheriting object classes across languages, etc. The programmer writes an interface file containing a list of C/C++ functions to be made visible to an interpreter. SWIG will compile the interface file and generate code in regular C/C++ and the target programming language. SWIG will generate conversion code for functions with simple arguments; conversion code for complex types of arguments must be written by the programmer. The SWIG tool creates source code that provides the glue between C/C++ and the target language. Depending on the language, this glue comes in two forms:
a shared library that an extant interpreter can link to as some form of extension module, or
a shared library that can be linked to other programs compiled in the target language (for example, using Java Native Interface (JNI) in Java).
SWIG is not used for calling interpreted functions by native code; this must be done by the programmer manually.
Example
SWIG wraps simple C declarations by creating an interface that closely matches the way in which the declarations would be used in a C program. For example, consider the following interface file:
%module example
%inline %{
extern double sin(double x);
extern int strcmp(const char *, const char *);
extern int Foo;
%}
#define STATUS 50
#define VERSION "1.1"
In this file, there are two functions and , a global variable , and two constants and . When SWIG creates an extension module |
https://en.wikipedia.org/wiki/FarPoint%20Spread | FarPoint Spread is a suite of Microsoft Excel-compatible spreadsheet components available for .NET, COM, and Microsoft BizTalk Server. Software developers use the components to embed Microsoft Excel-compatible spreadsheet features into their applications, such as importing and exporting Microsoft Excel files, displaying, modifying, analyzing, and visualizing data. Spread components handle spreadsheet data at the cell, row, column, or worksheet level.
This article is about the last FarPoint edition of the Spread product line. Spread is now developed by GrapeCity, Inc. Since the acquisition, Spread for Biztalk Server has been removed from the product line and SpreadJS, a JavaScript version, has been added.
History
1991 Spread released as a DLL control as the initial product offering from FarPoint Technologies, Inc.
1990s
Spread VBX released.
Spread ActiveX released.
These components are now known as Spread COM.
2003 Spread for Windows Forms released as a completely new managed C# version prompted by the launch of Visual Studio .NET.
2003 Spread for Web Forms (now Spread for ASP.NET) released.
2006 Spread for BizTalk released.
2009 FarPoint Technologies acquired by GrapeCity.
Versions
Spread for Windows Forms: 5.0
Spread for Web Forms: 5.0
Spread COM: 8.0
Spread for BizTalk: 3.0
Spread for Windows Forms
FarPoint Spread for Windows Forms is a Microsoft Excel-compatible spreadsheet component for Windows Forms applications developed using Microsoft Visual Studio and the .NET Framework. Developers use it to add grids and spreadsheets to their applications, and to bind them to data sources. In version 4.0, new cell types were added to display barcodes and fractions, and exports for XML and PDF were added.
Spread for ASP.NET
FarPoint Spread for ASP.NET is a Microsoft Excel-compatible spreadsheet component for ASP.NET applications. Developers use it to add grids and spreadsheets to their applications,
Spread for COM
FarPoint Spread 8 COM allows COM an |
https://en.wikipedia.org/wiki/Shaker%20%28gene%29 | The shaker (Sh) gene, when mutated, causes a variety of atypical behaviors in the fruit fly, Drosophila melanogaster. Under ether anesthesia, the fly’s legs will shake (hence the name); even when the fly is unanaesthetized, it will exhibit aberrant movements. Sh-mutant flies have a shorter lifespan than regular flies; in their larvae, the repetitive firing of action potentials as well as prolonged exposure to neurotransmitters at neuromuscular junctions occurs.
In Drosophila, the shaker gene is located on the X chromosome. The closest human homolog is KCNA3.
Function
The Sh gene plays a part in the operation of potassium ion channels, which are integral membrane proteins and are essential to the correct functioning of the cell. A working shaker channel is voltage-dependent and has four subunits, which form a pore through which ions flow, carrying type-A potassium current (IA). A mutation in the Sh gene reduces the conductance of charge across the neuron since the channels do not work, causing the severe phenotypical aberrations mentioned above. These types of ion channels are responsible for the repolarization of the cell.
The shaker K channel is a homo tetrameric protein complex. When confronted with a stimulus, the tetramers undergo conformational changes; some of these changes are cooperative. The final step involved in the opening of the channel is highly synchronized.
Recently, the shaker gene has also been identified as a gene that helps determine an organism's amount of sleep. The phenotype of the flies that need less sleep is called minisleep (mns).
Blockers
The shaker K channel is affected by various toxins, which effectively slow the opening of the channel, or reversibly block its functioning.
Toxins that affect the shaker K channel include:
Agitoxin
Charybdotoxin
Iberiotoxin
Pandinotoxin
6-bromo-2-mercaptotryptamine (BrMT)
BrMT can be seen working in the K channel to prevent the early activation of the channel – before the cooperation h |
https://en.wikipedia.org/wiki/Circuit-level%20gateway | A circuit-level gateway is a type of firewall.
Circuit-level gateways work at the session layer of the OSI model, or as a "shim-layer" between the application layer and the transport layer of the TCP/IP stack. They monitor TCP handshaking between packets to determine whether a requested session is legitimate. Information passed to a remote computer through a circuit-level gateway appears to have originated from the gateway. Firewall traffic is cleaned based on particular session rules and may be controlled to acknowledged computers only. Circuit-level firewalls conceal the details of the protected network from the external traffic, which is helpful for interdicting access to impostors. Circuit-level gateways are relatively inexpensive and have the advantage of hiding information about the private network they protect. However, they do not filter individual packets.
See also
Application firewall
Application-level gateway firewall
Bastion host
Dual-homed
External links
http://netsecurity.about.com/cs/generalsecurity/g/def_circgw.htm
http://www.softheap.com/internet/circuit-level-gateway.html
http://www.pcstats.com/articleview.cfm?articleid=1450&page=5
Internet architecture
Network socket
Transmission Control Protocol |
https://en.wikipedia.org/wiki/Bryan%20Sykes | Bryan Clifford Sykes (9 September 1947 – 10 December 2020) was a British geneticist and science writer who was a Fellow of Wolfson College and Emeritus Professor of human genetics at the University of Oxford.
Sykes published the first report on retrieving DNA from ancient bone (Nature, 1989). He was involved in a number of high-profile cases dealing with ancient DNA, including that of Ötzi the Iceman. He also suggested a Florida accountant by the name of Tom Robinson was a direct descendant of Genghis Khan, a claim that was subsequently disproved.
Sykes is best known outside the community of geneticists for his two popular books on the investigation of human history and prehistory through studies of mitochondrial DNA.
Education
Sykes was educated at Eltham College, received his BSc from the University of Liverpool, his PhD from the University of Bristol, and his DSc from the University of Oxford.
Career
The Seven Daughters of Eve
In 2001 (Banta Press Hardback) Sykes published a book for the popular audience, The Seven Daughters of Eve, in which he explained how the dynamics of maternal mitochondrial DNA (mtDNA) inheritance leave their mark on the human population in the form of genetic clans sharing common maternal descent. He notes that the majority of Europeans can be classified in seven such clans, known scientifically as haplogroups, distinguishable by differences in their mtDNA that are unique to each group, with each clan descending from a separate prehistoric female-line ancestor. He referred to these seven 'clan mothers' as 'daughters of Eve', a reference to the mitochondrial Eve to whom the mtDNA of all modern humans traces. Based on the geographical and ethnological distribution of the modern descendants of each clan he assigned provisional homelands for the seven clan mothers, and used the degree to which each clan diverges to approximate the time period when the clan mother would have lived. He then uses these deductions to give 'biographies' |
https://en.wikipedia.org/wiki/Clerodendrum%20golden%20mosaic%20China%20virus | Clerodendrum golden mosaic China virus (ClGMCNV) is a bipartite Begomovirus isolated from flowering plants in the Clerodendrum genus. The virus causes yellow mosaic disease in various plant species, including Nicotiana, Petunia, Solanum, and Capsicum species. It is associated with a mosaic disease known as 'Dancing Flame'. |
https://en.wikipedia.org/wiki/Neil%20Trudinger | Neil Sidney Trudinger (born 20 June 1942) is an Australian mathematician, known particularly for his work in the field of nonlinear elliptic partial differential equations.
After completing his B.Sc at the University of New England (Australia) in 1962, he continued his graduate studies at Stanford University.
He was awarded a Ph.D in 1966 for his thesis "Quasilinear Elliptical Partial Differential Equations in n Variables".
After the award of his doctorate from Stanford University, Trudinger became a Courant Instructor at the Courant Institute of Mathematical Sciences of New York University during the academic year 1966–67. He then returned to Australia where he was appointed as a lecturer at Macquarie University in 1967. In 1970, he moved to University of Queensland where he was first appointed as a Reader, then as Professor. In 1973 he moved to the Australian National University. In 2016 he moved to the University of Wollongong, where he is currently appointed as a Distinguished Professor.
At the ANU Trudinger served as Head of the Department of Pure Mathematics, as Director of the Centre for Mathematical Analysis and as Director of the Centre for Mathematics and its Applications, before becoming Dean of the School of Mathematical Sciences in 1992. He currently coordinates ANU's Applied and Nonlinear Analysis program.
He is co-author, together with his thesis advisor, David Gilbarg, of the book Elliptic Partial Differential Equations of Second Order.
Honours
1978, elected as a fellow of the Australian Academy of Science.
1981, first recipient of the Australian Mathematical Society Medal.
1996, awarded the Hannan Medal of the Australian Academy of Science.
1997, elected as a Fellow of the Royal Society of London.
2008, awarded the Leroy P. Steele Prize for Mathematical Exposition by the American Mathematical Society.
2012, elected as a fellow of the American Mathematical Society.
2014, gave the Łojasiewicz Lecture (on the "Optimal Transportation in the 2 |
https://en.wikipedia.org/wiki/Radiation%20efficiency | In antenna theory, radiation efficiency is a measure of how well a radio antenna converts the radio-frequency power accepted at its terminals into radiated power. Likewise, in a receiving antenna it describes the proportion of the radio wave's power intercepted by the antenna which is actually delivered as an electrical signal. It is not to be confused with antenna efficiency, which applies to aperture antennas such as a parabolic reflector or phased array, or antenna/aperture illumination efficiency, which relates the maximum directivity of an antenna/aperture to its standard directivity.
Definition
Radiation efficiency is defined as "The ratio of the total power radiated by an antenna to the net power accepted by the antenna from the connected transmitter." It is sometimes expressed as a percentage (less than 100), and is frequency dependent. It can also be described in decibels. The gain of an antenna is the directivity multiplied by the radiation efficiency. Thus, we have
where is the gain of the antenna in a specified direction, is the radiation efficiency, and is the directivity of the antenna in the specified direction.
For wire antennas which have a defined radiation resistance the radiation efficiency is the ratio of the radiation resistance to the total resistance of the antenna including ground loss (see below) and conductor resistance. In practical cases the resistive loss in any tuning and/or matching network is often included, although network loss is strictly not a property of the antenna.
For other types of antenna the radiation efficiency is less easy to calculate and is usually determined by measurements.
Radiation efficiency of an antenna or antenna array having several ports
In the case of an antenna or antenna array having multiple ports, the radiation efficiency depends on the excitation. More precisely, the radiation efficiency depends on the relative phases and the relative amplitudes of the signals applied to the different ports |
https://en.wikipedia.org/wiki/Kerala%20school%20of%20astronomy%20and%20mathematics | The Kerala school of astronomy and mathematics or the Kerala school was a school of mathematics and astronomy founded by Madhava of Sangamagrama in Tirur, Malappuram, Kerala, India, which included among its members: Parameshvara, Neelakanta Somayaji, Jyeshtadeva, Achyuta Pisharati, Melpathur Narayana Bhattathiri and Achyuta Panikkar. The school flourished between the 14th and 16th centuries and its original discoveries seem to have ended with Narayana Bhattathiri (1559–1632). In attempting to solve astronomical problems, the Kerala school independently discovered a number of important mathematical concepts. Their most important results—series expansion for trigonometric functions—were described in Sanskrit verse in a book by Neelakanta called Tantrasangraha, and again in a commentary on this work, called Tantrasangraha-vakhya, of unknown authorship. The theorems were stated without proof, but proofs for the series for sine, cosine, and inverse tangent were provided a century later in the work Yuktibhasa (), written in Malayalam, by Jyesthadeva, and also in a commentary on Tantrasangraha.
Their work, completed two centuries before the invention of calculus in Europe, provided what is now considered the first example of a power series (apart from geometric series).
Background
Islamic scholars nearly developed a general formula for finding integrals of polynomials by 1000 AD —and evidently could find such a formula for any polynomial in which they were interested. But, it appears, they were not interested in any polynomial of degree higher than four, at least in any of the material that has come down to us. Indian scholars, on the other hand, were by the year 1600 able to use formula similar to ibn al-Haytham's sum formula for arbitrary integral powers in calculating power series for the functions in which they were interested. By the same time, they also knew how to calculate the differentials of these functions. So some of the basic ideas of calculus were know |
https://en.wikipedia.org/wiki/Puncheon%20%28unit%29 | The puncheon was a British unit for beer, wines and spirits. It was also an American unit of capacity for wine.
Definition
Historically, the puncheon has been defined somewhere between .
US unit of capacity for wine
The US puncheon for wine is defined as .
Conversion
1 puncheon = 70-120 gallons
1 puncheon = 0.318-0.546 m3 or 318 to 546 litres.
US unit of capacity for wine
1 puncheon = 4/3 Hogshead
1 puncheon = 84 gallons
1 puncheon = 0.317974589856 m3 or about 318 litres.
See also
English wine cask units |
https://en.wikipedia.org/wiki/Abrizio | Abrizio was a fabless semiconductor company which made switching fabric chip sets (integrated circuits for computer network switches). Their chip set, the TT1, was used by several large system development companies as the core switch fabric in their high value communication systems.
Founding
Abrizio was founded in 1997, by Professor Nick McKeown as a spinout of the Tiny-tera project at Stanford University. It received US$6M of funding from Benchmark Capital and Sequoia Capital.
Product and technology
The product name TT1 referred to "Tiny Tera" meaning a small, highly integrated semiconductor implementation of a terabit/s capacity switching fabric. The Stanford program demonstrated a scalable packet switch that had a terabit-per-second performance in CMOS. Abrizio was the first to introduce a more optimized Input-Buffered Output Queued Switch Fabrics, which addressed the memory efficiency issue of similar technologies. Its technology made better use of memory, making the TT1 a less expensive product. Abrizio's key technology was a sophisticated implementation of a Wavefront arbiter which allowed the switch to make complex arbitration decisions very quickly.
Senior leadership
In 1998, Anders Swahn, who had been executive vice president of sales and marketing at Allied-Telesyn Inc., joined Abrizio as chief executive. Abrizio's corporate colors were purple and yellow. The CEO of Abrizio was Anders Swahn. The CTO was McKeown who was taking a leave from his professorship at Stanford. Zubair Hussein was the V.P. of Engineering.
Acquisition
Abrizio was acquired on August 24, 1999, by PMC-Sierra for 4,352,000 shares of PMC-Sierra stock, worth at that time $400M. After the acquisition, the former Abrizio development team completed the TTx switch chip set. In the wake of the bursting of the telecom bubble, PMC-Sierra laid off most of the former Abrizio team in 2001. |
https://en.wikipedia.org/wiki/Glossary%20of%20beekeeping | This page is a glossary of beekeeping.
A
Africanized bee – a hybrid bee with characteristics unsuitable for beekeeping
Apiary – a yard where beehives are kept
Apicology – ecology of bees
Apiology – scientific study of bees
Apitherapy – a branch of alternative medicine that uses honey bee products including honey, pollen, propolis, royal jelly and bee venom.
B
Bee – a member of the order that includes ants and wasps
Bee anatomy (mouth)
Bee bread – the main source of food for most honey bees and their larvae
Beekeeper – also called apiarist or apiculturist, a person who cares for bees
Bee learning and communication
Bee museums
Bee sting
Bee venom therapy – also called apitherapy
Beehive – a housing for cavity-dwelling bees that allows inspection and honey removal
Beekeeping – bees are kept for their products (principally honey), and their utility in pollinating crops
Bees and toxic chemicals
Brood (honey bee) – the egg, larval, and pupal form of the bee and the comb in which they develop
Buckfast bee – a productive breed of bee suitable for damp and cloudy climes
C
Carniolan honey bee – a gentle bee good for variable nectar flow
Characteristics of common wasps and bees
Colony Collapse Disorder – malady of unknown cause characterized by disappearance of bees from hive
D
Deseret – the beehive and its symbolism to the Church of Jesus Christ of Latter-day Saints (Mormons)
Diseases of the honey bee
Drone bee – the male bee
Drone laying queen
H
Honey bee – all the species in the genus Apis
Honey bee life cycle – the physical stages in the development of a mature bee starting from the egg
I
Italian bee – the most well known honey bee subspecies
L
Laying worker bee – this worker will produce only drone bees
Langstroth hive – commonly seen in developed countries as stacks of white or muted colored boxes at the edges of fields and orchards
N
Northern Nectar Sources for Honey Bees – common names and descriptions of northern latitude necta |
https://en.wikipedia.org/wiki/Matrotrophy | Matrotrophy is a form of maternal care during organism development, associated with live birth (viviparity), in which the embryo of an animal or flowering plant is supplied with additional nutrition from the mother (e.g. through a placenta). This can be contrasted with lecithotrophy, in which the only source of nutrition for the embryo is yolk originally contained within its egg.
Vegetal matrotrophy
In plants, matrotrophy is considered a critical evolutionary development preceding the origin of embryophytes and therefore essential to the evolution of land plants. Matrotrophy is facilitated by cytological and ultrastructural modifications on one or both sides of the generational junction, a region called the placenta. Specialization of the placental cells pertains further to their cytological and ultrastructural characteristics: the cytoplasm is often dense and rich in lipids, the vacuole is typically reduced but large in Sphagnum, the endoplasmic reticulum extensive, mitochondria numerous and large, chloroplasts numerous, often less differentiated, rich in lipid-filled globuli and sometimes filled with starch.
Animal matrotrophy
While commonly associated with vertebrates and especially mammals, matrotrophy is found in 21 of 34 animal phyla, and is fairly common in 11 of those. It has arisen independently in more than 150 clades within Chordata and in more than 140 clades amongst invertebrates.
See also
Pregnancy (fish) |
https://en.wikipedia.org/wiki/Mazur%E2%80%93Ulam%20theorem | In mathematics, the Mazur–Ulam theorem states that if and are normed spaces over R and the mapping
is a surjective isometry, then is affine. It was proved by Stanisław Mazur and Stanisław Ulam in response to a question raised by Stefan Banach.
For strictly convex spaces the result is true, and easy, even for isometries which are not necessarily surjective. In this case, for any and in , and for any in , write
and denote the closed ball of radius around by . Then is the unique element of , so, since is injective, is the unique element of
and therefore is equal to . Therefore is an affine map. This argument fails in the general case, because in a normed space which is not strictly convex two tangent balls may meet in some flat convex region of their boundary, not just a single point.
See also
Aleksandrov–Rassias problem |
https://en.wikipedia.org/wiki/Mir-612%20microRNA%20precursor%20family | mir-612 microRNA is a short non-coding RNA molecule belonging both to the family of microRNAs and to that of small interfering RNAs (siRNAs). MicroRNAs function to regulate the expression levels of other genes by several mechanisms, whilst siRNAs are involved primarily with the RNA interference (RNAi) pathway. siRNAs have been linked through some members to the regulation of cancer cell growth, specifically in prostate adenocarcinoma.
miR-612 and p53
The microRNA miR-2185 has a strong inhibitory effect on the tumour suppressor protein p53, acting through targeting its 3'UTR. MiR-612 is of the same seed sequence as miR-2185 but, despite this, is yet to be identified as a p53 inhibitor.
See also
MicroRNA |
https://en.wikipedia.org/wiki/Riemann%E2%80%93Lebesgue%20lemma | In mathematics, the Riemann–Lebesgue lemma, named after Bernhard Riemann and Henri Lebesgue, states that the Fourier transform or Laplace transform of an L1 function vanishes at infinity. It is of importance in harmonic analysis and asymptotic analysis.
Statement
Let be an integrable function, i.e. is a measurable function such that
and let be the Fourier transform of , i.e.
Then vanishes at infinity: as .
Because the Fourier transform of an integrable function is continuous, the Fourier transform is a continuous function vanishing at infinity. If denotes the vector space of continuous functions vanishing at infinity, the Riemann–Lebesgue lemma may be formulated as follows: The Fourier transformation maps to .
Proof
We will focus on the one-dimensional case , the proof in higher dimensions is similar. First, suppose that is continuous and compactly supported. For , the substitution leads to
.
This gives a second formula for . Taking the mean of both formulas, we arrive at the following estimate:
.
Because is continuous, converges to as for all . Thus, converges to 0 as due to the dominated convergence theorem.
If is an arbitrary integrable function, it may be approximated in the norm by a compactly supported continuous function. For , pick a compactly supported continuous function such that . Then
Because this holds for any , it follows that as .
Other versions
The Riemann–Lebesgue lemma holds in a variety of other situations.
If , then the Riemann–Lebesgue lemma also holds for the Laplace transform of , that is,
as within the half-plane .
A version holds for Fourier series as well: if is an integrable function on a bounded interval, then the Fourier coefficients of tend to 0 as . This follows by extending by zero outside the interval, and then applying the version of the Riemann–Lebesgue lemma on the entire real line.
However, the Riemann–Lebesgue lemma does not hold for arbitrary distributions. For example, the Dirac delta |
https://en.wikipedia.org/wiki/Dialectica%20interpretation | In proof theory, the Dialectica interpretation is a proof interpretation of intuitionistic logic (Heyting arithmetic) into a finite type extension of primitive recursive arithmetic, the so-called System T. It was developed by Kurt Gödel to provide a consistency proof of arithmetic. The name of the interpretation comes from the journal Dialectica, where Gödel's paper was published in a 1958 special issue dedicated to Paul Bernays on his 70th birthday.
Motivation
Via the Gödel–Gentzen negative translation, the consistency of classical Peano arithmetic had already been reduced to the consistency of intuitionistic Heyting arithmetic. Gödel's motivation for developing the dialectica interpretation was to obtain a relative consistency proof for Heyting arithmetic (and hence for Peano arithmetic).
Intuitionistic logic
The interpretation has two components: a formula translation and a proof translation. The formula translation describes how each formula of Heyting arithmetic is mapped to a quantifier-free formula of the system T, where and are tuples of fresh variables (not appearing free in ). Intuitively, is interpreted as . The proof translation shows how a proof of has enough information to witness the interpretation of , i.e. the proof of can be converted into a closed term and a proof of in the system T.
Formula translation
The quantifier-free formula is defined inductively on the logical structure of as follows, where is an atomic formula:
Proof translation (soundness)
The formula interpretation is such that whenever is provable in Heyting arithmetic then there exists a sequence of closed terms such that is provable in the system T. The sequence of terms and the proof of are constructed from the given proof of in Heyting arithmetic. The construction of is quite straightforward, except for the contraction axiom which requires the assumption that quantifier-free formulas are decidable.
Characterisation principles
It has also been shown |
https://en.wikipedia.org/wiki/Probabilistic%20genotyping | Probabilistic genotyping is the use of statistical methods and mathematical algorithms in DNA Profiling. It may be used instead of manual methods in difficult situations, such as when a DNA sample is very small or includes a mixture of multiple individuals' DNA. Probabilistic genotyping, unlike traditional methods, avoids the need for subjective judgment. The reliability of the method has been questioned by some defense lawyers because the source code of some probabilistic genotyping programs is proprietary. |
https://en.wikipedia.org/wiki/Avionics%20software | Avionics software is embedded software with legally mandated safety and reliability concerns used in avionics. The main difference between avionic software and conventional embedded software is that the development process is required by law and is optimized for safety.
It is claimed that the process described below is only slightly slower and more costly (perhaps 15 percent) than the normal ad hoc processes used for commercial software. Since most software fails because of mistakes, eliminating the mistakes at the earliest possible step is also a relatively inexpensive and reliable way to produce software. In some projects however, mistakes in the specifications may not be detected until deployment. At that point, they can be very expensive to fix.
The basic idea of any software development model is that each step of the design process has outputs called "deliverables." If the deliverables are tested for correctness and fixed, then normal human mistakes can not easily grow into dangerous or expensive problems. Most manufacturers follow the waterfall model to coordinate the design product, but almost all explicitly permit earlier work to be revised. The result is more often closer to a spiral model.
For an overview of embedded software see embedded system and software development models. The rest of this article assumes familiarity with that information, and discusses differences between commercial embedded systems and commercial development models.
General overview
Since most avionics manufacturers see software as a way to add value without adding weight, the importance of embedded software in avionic systems is increasing.
Most modern commercial aircraft with auto-pilots use flight computers and so called flight management systems (FMS) that can fly the aircraft without the pilot's active intervention during certain phases of flight. Also under development or in production are unmanned vehicles: missiles and drones which can take off, cruise and land wi |
https://en.wikipedia.org/wiki/Object-capability%20model | The object-capability model is a computer security model. A capability describes a transferable right to perform one (or more) operations on a given object. It can be obtained by the following combination:
An unforgeable reference (in the sense of object references or protected pointers) that can be sent in messages.
A message that specifies the operation to be performed.
The security model relies on not being able to forge references.
Objects can interact only by sending messages on references.
A reference can be obtained by:
Initial conditions: In the initial state of the computational world being described, object A may already have a reference to object B.
Parenthood: If A creates B, at that moment A obtains the only reference to the newly created B.
Endowment: If A creates B, B is born with that subset of A's references with which A chose to endow it.
Introduction: If A has references to both B and C, A can send to B a message containing a reference to C. B can retain that reference for subsequent use.
In the object-capability model, all computation is performed following the above rules.
Advantages that motivate object-oriented programming, such as encapsulation or information hiding, modularity, and separation of concerns, correspond to security goals such as least privilege and privilege separation in capability-based programming.
The object-capability model was first proposed by Jack Dennis and Earl C. Van Horn in 1966.
Loopholes in object-oriented programming languages
Some object-based programming languages (e.g. JavaScript, Java, and C#) provide ways to access resources in other ways than according to the rules above including the following:
Direct assignment to the instance variables of an object in Java and C#.
Direct reflective inspection of the meta-data of an object in Java and C#.
The pervasive ability to import primitive modules, e.g. java.io.File that enable external effects.
Such use of undeniable authority violates the condition |
https://en.wikipedia.org/wiki/International%20Radon%20Project | The International Radon Project (IRP) is a World Health Organization initiative to reduce the lung cancer risk around the world.
The IRP released their guidance to member countries in September 2009.
Exposure to radon in the home and workplace is one of the main risks of ionizing radiation causing tens of thousands of deaths from lung cancer each year globally. In order to reduce this burden it is important that national authorities have methods and tools based on solid scientific evidence and sound public health policy. The public needs to be aware of radon risks and the means to reduce and prevent these.
In 1996, WHO published a report containing several conclusions and recommendations covering the scientific understanding of radon risk and the need for countries to take action in the areas of risk management and risk communication.
Recent findings from case-control studies on lung cancer and exposure to radon in homes completed in many countries allow for substantial improvement in risk estimates and for further consolidation of knowledge by pooling data from these studies. The consistency of the findings from the latest pooled analyses of case-control studies from Europe and North America as well as China provides a strong argument for an international initiative to reduce indoor radon risks.
To fulfill these goals, WHO has developed a program on public health aspects of radon exposure. This project enjoys high priority with WHO's Department of Public Health and Environment. The key elements of the International Radon Project include:
Estimation of the global burden of disease (GBD) associated with exposure to radon, based on the establishment of a global radon database
Provision of guidance on methods for radon measurements and mitigation
Developing evidence-based public health guidance for Member States to formulate policy and advocacy strategy including the establishment of radon action levels
Development of approaches for radon risk communication.
|
https://en.wikipedia.org/wiki/67th%20meridian%20east | The meridian 67° east of Greenwich is a line of longitude that extends from the North Pole across the Arctic Ocean, Asia, the Indian Ocean, the Southern Ocean, and Antarctica to the South Pole.
The 67th meridian east forms a great circle with the 113th meridian west.
From Pole to Pole
Starting at the North Pole and heading south to the South Pole, the 67th meridian east passes through:
{| class="wikitable plainrowheaders"
! scope="col" width="115" | Co-ordinates
! scope="col" | Country, territory or sea
! scope="col" | Notes
|-
| style="background:#b0e0e6;" |
! scope="row" style="background:#b0e0e6;" | Arctic Ocean
| style="background:#b0e0e6;" |
|-
| style="background:#b0e0e6;" |
! scope="row" style="background:#b0e0e6;" | Barents Sea
| style="background:#b0e0e6;" |
|-
|
! scope="row" |
| Severny Island, Novaya Zemlya, Arkhangelsk Oblast
|-
| style="background:#b0e0e6;" |
! scope="row" style="background:#b0e0e6;" | Kara Sea
| style="background:#b0e0e6;" |
|-
|
! scope="row" |
| Yamal Peninsula, Yamalo-Nenets Autonomous Okrug
|-
| style="background:#b0e0e6;" |
! scope="row" style="background:#b0e0e6;" | Kara Sea
| style="background:#b0e0e6;" |
|-
|
! scope="row" |
| Yamal Peninsula, Yamalo-Nenets Autonomous Okrug
|-
| style="background:#b0e0e6;" |
! scope="row" style="background:#b0e0e6;" | Kara Sea
| style="background:#b0e0e6;" | Baydaratskaya Bay
|-
|
! scope="row" |
| Yamalo-Nenetsia, Khantia-Mansia, Tyumen Oblast, Kurgan Oblast
|-
|
! scope="row" |
| North Kazakhstan Region, Akmola Region, Karaganda Region, Turkistan Region
|-
|
! scope="row" |
| Jizzax Region, Samarkand Region (passing through Samarkand), Qashqadaryo Region, Surxondaryo Region
|-
|
! scope="row" |
| Balkh Province, Samangan Province, Sar-e Pol Province, Bamyan Province, Daykundi Province, Ghazni Province, Uruzgan Province, Zabul Province, Kandahar Province
|-valign="top"
|
! scope="row" |
| Balochistan Sindh - passing through Karachi
|-
| style="background:#b0e0e6;" |
! |
https://en.wikipedia.org/wiki/Banna%27i | In Iranian architecture, banna'i (, "builder's technique" in Persian) is an architectural decorative art in which glazed tiles are alternated with plain bricks to create geometric patterns over the surface of a wall or to spell out sacred names or pious phrases. This technique originated in Syria and Iraq in the 8th century, and matured in the Seljuq and Timurid era, as it spread to Iran, Anatolia and Central Asia.
If the brickwork design is in relief then it is referred to as hazarbaf (, compound of hazar "thousand" and baf "weavings", referring to the woven appearance of the bricks).
History
The earliest surviving example of decorative brick work with colored bricks is found in the city gate of Raqqa (c. 772). The earliest known example of hazārbāf is found in the Ukhaydir Palace near Baghdad, built around 762. The technique appeared in Iran and central Asia more than a century later but with more sophisticated designs. The tomb of the Samanid ruler Ismā'īl (in Bukhara, Uzbekistan), had walls with protruding and recessed bricks that created a weaving pattern.
Islamic brickwork grew in sophistication of its techniques over the centuries. In the 11th century, the use of multiple brick sizes, and variation in the depth of the joint between bricks formed shadow that contrasted strongly with the horizontal lines of the brick rows (for example the Arslan Jadhib Mausoleum in the Sang-Bast complex). Rows of brick were set deep inside the face of the building and raised above it, to create positive and negative spaces (for example in the Damghan minaret and Pir-e Alamdar tower). The Chehel Dokhtaran minaret in Isfahan (built 1107-1108) is one of the earliest example of brick work with triangles, squares, octagons, cruciform designs (another example, minaret of Saveh, has raised brickwork in Kufic and Nashki script). The Gunbad-i Sorkh monument in Azerbaijan (built in 1147) was made of ten different types of carved bricks in its corner columns.
In the 12th century in A |
https://en.wikipedia.org/wiki/Krzysztof%20R.%20Apt | Krzysztof R. Apt (born 26 December 1949 in Katowice, Poland)
is a Polish computer scientist. He defended his PhD in mathematical logic in
Warsaw, Poland in 1974. His research interests include program correctness and semantics, use
of logic as a programming language, distributed computing, and game theory. Besides his own research, he has been heavily involved in service to
the computing community, notably by promoting the
use of logic in computer science (in particular by founding a new
journal) and by advocating open access to scientific literature.
Academic career
Apt has held various scientific positions in Poland, the Netherlands,
France, the U.S. (the William B. Blakemore II Professor, Computer
Science, UT Austin, 1987–1990), and Singapore (Visiting
Professor, Computer Science, NUS, 2002–2005).
Apt is a Fellow at CWI (National Research Institute for Mathematics and Computer Science)
in Amsterdam and Affiliated Professor at the University of Warsaw. Since 2014 he is also Professor Emeritus at the University of Amsterdam.
His research interests include program correctness and semantics, use
of logic as a programming language, distributed computing, and game theory. In particular, with coauthors he introduced the concept of
stratification in logic programming to provide a way to deal with
negation in logic and Datalog programs. His comprehensive survey of Hoare logic, written with
Ernst-Rüdiger Olderog, summarizes
the history of the subject since its inception in 1969.
Apt is a member of Academia Europaea, which serves as "a pan-European Academy of Sciences, Humanities and Letters"; membership is by invitation only and follows a rigorous peer review selection process.
He is the founder and first
Editor-in-Chief of the ACM Transactions on Computational Logic and
past president of the Association for Logic Programming (ALP). He is one of the three initiators of the Witold Lipski Prize for Young Researchers in Computer Science.
Apt has long been an active advoc |
https://en.wikipedia.org/wiki/Lise%20Meitner%20Distinguished%20Lecture | Lise Meitner Distinguished Lecture and Medal is a colloquium-style distinguished lecture that takes place at AlbaNova University Center in Stockholm on annual basis. The lecture commemorates Lise Meitner, who spent a substantial part of her career in Stockholm. AlbaNova University Center hosts physics departments of the Royal Institute of Technology, Stockholm University and Nordita.
The Lise Meitner Distinguished Lecture is sponsored by Royal Swedish Academy of Sciences through its Nobel Committee for Physics.
Past lectures
2015: Frank Wilczek (MIT)Physics in 100 years
2016: Bert Halperin (Harvard University)Defects with Character: Zero-Energy Majorana Modes in Condensed-Matter Systems
2017: Duncan Haldane (Princeton University)Topological Quantum Matter and Entanglement
2018: Lene Vestergaard Hau (Harvard University) The art of taming light
2019: Michael Berry (Bristol University) Geometric phases and the separation of the world
2020: Immanuel Bloch (Max-Planck-Institute of Quantum Optics, Garching)
2021: Pablo Jarillo-Herrero (MIT)
2022: Peter Shor (MIT)
See also
Lise Meitner Lectures
Meitner Medal
Oskar Klein Memorial Lecture
List of physics awards |
https://en.wikipedia.org/wiki/Micromagnetics | Micromagnetics is a field of physics dealing with the prediction of magnetic behaviors at sub-micrometer length scales. The length scales considered are large enough for the atomic structure of the material to be ignored (the continuum approximation), yet small enough to resolve magnetic structures such as domain walls or vortices.
Micromagnetics can deal with static equilibria, by minimizing the magnetic energy, and with dynamic behavior, by solving the time-dependent dynamical equation.
History
Micromagnetics as a field (i.e., that deals specifically with the behaviour of ferromagnetic materials at sub-micrometer length scales) was introduced in 1963 when William Fuller Brown Jr. published a paper on antiparallel domain wall structures. Until comparatively recently computational micromagnetics has been prohibitively expensive in terms of computational power, but smaller problems are now solvable on a modern desktop PC.
Static micromagnetics
The purpose of static micromagnetics is to solve for the spatial distribution of the magnetization M at equilibrium. In most cases, as the temperature is much lower than the Curie temperature of the material considered, the modulus |M| of the magnetization is assumed to be everywhere equal to the saturation magnetization Ms. The problem then consists in finding the spatial orientation of the magnetization, which is given by the magnetization direction vector m = M/Ms, also called reduced magnetization.
The static equilibria are found by minimizing the magnetic energy,
,
subject to the constraint |M|=Ms or |m|=1.
The contributions to this energy are the following:
Exchange energy
The exchange energy is a phenomenological continuum description of the quantum-mechanical exchange interaction. It is written as:
where A is the exchange constant; mx, my and mz are the components of m;
and the integral is performed over the volume of the sample.
The exchange energy tends to favor configurations where the magnetization varies |
https://en.wikipedia.org/wiki/Heterogeneous%20Element%20Processor | The Heterogeneous Element Processor (HEP) was introduced by Denelcor, Inc. in 1982. The HEP's architect was Burton Smith. The machine was designed to solve fluid dynamics problems for the Ballistic Research Laboratory. A HEP system, as the name implies, was pieced together from many heterogeneous components -- processors, data memory modules, and I/O modules. The components were connected via a switched network.
A single processor, called a PEM, in a HEP system (up to sixteen PEMs could be connected) was rather unconventional; via a "program status word (PSW) queue," up to fifty processes could be maintained in hardware at once. The largest system ever delivered had 4 PEMs. The eight-stage instruction pipeline allowed instructions from eight different processes to proceed at once. In fact, only one instruction from a given process was allowed to be present in the pipeline at any point in time. Therefore, the full processor throughput of 10 MIPS could only be achieved when eight or more processes were active; no single process could achieve throughput greater than 1.25 MIPS. This type of multithreading processing classifies the HEP as a barrel processor. The hardware implementation of the HEP PEM was emitter-coupled logic.
Processes were classified as either user-level or supervisor-level. User-level processes could create supervisor-level processes, which were used to manage user-level processes and perform I/O. Processes of the same class were required to be grouped into one of seven user tasks and seven supervisor tasks.
Each processor, in addition to the PSW queue and instruction pipeline, contained instruction memory, 2,048 64-bit general purpose registers and 4,096 constant registers. Constant registers were differentiated by the fact that only supervisor processes could modify their contents. The processors themselves contained no data memory; instead, data memory modules could be separately attached to the switched network.
The HEP memory consis |
https://en.wikipedia.org/wiki/Laminar%20flow%20cabinet | A laminar flow cabinet or tissue culture hood is a carefully enclosed bench designed to prevent contamination of semiconductor wafers, biological samples, or any particle sensitive materials. Air is drawn through a HEPA filter and blown in a very smooth, laminar flow towards the user. Due to the direction of air flow, the sample is protected from the user but the user is not protected from the sample. The cabinet is usually made of stainless steel with no gaps or joints where spores might collect.
Such hoods exist in both horizontal and vertical configurations, and there are many different types of cabinets with a variety of airflow patterns and acceptable uses.
Laminar flow cabinets may have a UV-C germicidal lamp to sterilize the interior and contents before usage to prevent contamination of the experiment. Germicidal lamps are usually kept on for fifteen minutes to sterilize the interior before the cabinet is used. The light must be switched off when the cabinet is being used, to limit exposure to skin and eyes as stray ultraviolet light emissions can cause cancer and cataracts.
See also
Asepsis
Biosafety cabinet
Fume hood |
https://en.wikipedia.org/wiki/MX1%20Ltd | MX1 was a global media services provider founded in July 2016 from a merger between digital media services companies, RR Media and SES Platform Services, and a wholly owned subsidiary of global satellite owner and operator, SES.
In September 2019, MX1 was merged into the SES Video division and the MX1 brand dropped. Broadcast and streamed content management, playout, distribution, and monetisation services from both MX1 and SES Video are now provided under the SES name.
Before merger with SES, MX1 claimed to manage more than 5 million media assets and every day to distribute more than 3,600 TV channels, manage the playout of over 525 channels, distribute content to more than 120 subscription VOD platforms, and deliver over 8,400 hours of online video streaming and more than 620 hours of premium sports and live events.
Services
MX1 video and media services are provided through a single hybrid, cloud and on-premises solution, called MX1 360, which enables video and media solutions including content and metadata management, archiving, localisation solutions, channel playout, VOD, online video (OTT) and content distribution. Services provided by MX1 include:
Content aggregation
Acquisition of content via satellite, fibre or IP with satellite downlinking services (for encryption, re-encryption and re-muxing into different platforms), fibre reception from any location, and IP reception via the public Internet. Live sports, news and entertainment production (including in-studio, outside broadcasting, and SNG) with mobile live streaming and video contribution.
Content management
Digital mastering including scanning, conversion, restoration, quality control and localisation/versioning. Content archiving including secure, cloud and on-premises digital storage, and disaster recovery services. Metadata packaging and platform validation to enhance content discovery, searchability and cataloguing. Playout preparation and delivery to any format.
Channel origination and playo |
https://en.wikipedia.org/wiki/Sensory-motor%20map | In robotics one often combines external sensory input and motor kinematics. A Sensory Motor-Map(SMM) is a map between the perception system of the robot and an action performed by the robot. The map gives the robot an understanding of how certain motor actions affect the perceived reality by relating the kinematics and dynamics used by the robot to achieve the external sensory input. |
https://en.wikipedia.org/wiki/HTTP%20message%20body | HTTP Message Body is the data bytes transmitted in an HTTP transaction message immediately following the headers if there are any (in the case of HTTP/0.9 no headers are transmitted).
HTTP message
The request/response message consists of the following:
Request line, such as GET /logo.gif HTTP/1.1 or Status line, such as HTTP/1.1 200 OK,
Headers
An empty line
Optional HTTP message body data
The request/status line and headers must all end with (that is, a carriage return followed by a line feed). The empty line must consist of only and no other whitespace.
The "optional HTTP message body data" is what this article defines.
Response example
This could be a response from the web server:
HTTP/1.1 200 OK
Date: Sun, 10 Oct 2010 23:26:07 GMT
Server: Apache/2.2.8 (Ubuntu) mod_ssl/2.2.8 OpenSSL/0.9.8g
Last-Modified: Sun, 26 Sep 2010 22:04:35 GMT
ETag: "45b6-834-49130cc1182c0"
Accept-Ranges: bytes
Content-Length: 12
Connection: close
Content-Type: text/html
Hello world!
The message body (or content) in this example is the text Hello world!.
See also
HTTP
HTTP compression
List of HTTP headers
List of HTTP status codes
Web cache
Application layer protocols
Hypertext Transfer Protocol
Internet protocols
Network protocols
World Wide Web Consortium standards |
https://en.wikipedia.org/wiki/Stationary%20state | A stationary state is a quantum state with all observables independent of time. It is an eigenvector of the energy operator (instead of a quantum superposition of different energies). It is also called energy eigenvector, energy eigenstate, energy eigenfunction, or energy eigenket. It is very similar to the concept of atomic orbital and molecular orbital in chemistry, with some slight differences explained below.
Introduction
A stationary state is called stationary because the system remains in the same state as time elapses, in every observable way. For a single-particle Hamiltonian, this means that the particle has a constant probability distribution for its position, its velocity, its spin, etc. (This is true assuming the particle's environment is also static, i.e. the Hamiltonian is unchanging in time.) The wavefunction itself is not stationary: It continually changes its overall complex phase factor, so as to form a standing wave. The oscillation frequency of the standing wave, times Planck's constant, is the energy of the state according to the Planck–Einstein relation.
Stationary states are quantum states that are solutions to the time-independent Schrödinger equation:
where
This is an eigenvalue equation: is a linear operator on a vector space, is an eigenvector of , and is its eigenvalue.
If a stationary state is plugged into the time-dependent Schrödinger equation, the result is
Assuming that is time-independent (unchanging in time), this equation holds for any time . Therefore, this is a differential equation describing how varies in time. Its solution is
Therefore, a stationary state is a standing wave that oscillates with an overall complex phase factor, and its oscillation angular frequency is equal to its energy divided by .
Stationary state properties
As shown above, a stationary state is not mathematically constant:
However, all observable properties of the state are in fact constant in time. For example, if represents a simple one |
https://en.wikipedia.org/wiki/NLTS%20conjecture | In quantum information theory, the no low-energy trivial state (NLTS) conjecture is a precursor to a quantum PCP theorem (qPCP) and posits the existence of families of Hamiltonians with all low-energy states of non-trivial complexity. An NLTS proof would be a consequence of one aspect of qPCP problems the inability to certify an approximation of local Hamiltonians via NP completeness. In other words, an NLTS proof would be one consequence of the QMA complexity of qPCP problems. On a high level, if proved, NLTS would be one property of the non-Newtonian complexity of quantum computation. NLTS and qPCP conjectures posit the near-infinite complexity involved in predicting the outcome of quantum systems with many interacting states. These calculations of complexity would have implications for quantum computing such as the stability of entangled states at higher temperatures, and the occurrence of entanglement in natural systems. There is currently a proof of NLTS conjecture published in preprint.
NLTS property
The NLTS property is the underlying set of constraints that forms the basis for the NLTS conjecture.
Definitions
Local hamiltonians
A k-local Hamiltonian (quantum mechanics) is a Hermitian matrix acting on n qubits which can be represented as the sum of Hamiltonian terms acting upon at most qubits each:
The general k-local Hamiltonian problem is, given a k-local Hamiltonian , to find the smallest eigenvalue of . is also called the ground-state energy of the Hamiltonian.
The family of local Hamiltonians thus arises out of the k-local problem. Kliesch states the following as a definition for local Hamiltonians in the context of NLTS:
Let I ⊂ N be an index set. A family of local Hamiltonians is a set of Hamiltonians {H(n)}, n ∈ I, where each H(n) is defined on n finite-dimensional subsystems (in the following taken to be qubits), that are of the form
where each Hm(n) acts non-trivially on O(1) qubits. Another constraint is the operator norm of Hm(n) |
https://en.wikipedia.org/wiki/Matrix%20t-distribution | In statistics, the matrix t-distribution (or matrix variate t-distribution) is the generalization of the multivariate t-distribution from vectors to matrices. The matrix t-distribution shares the same relationship with the multivariate t-distribution that the matrix normal distribution shares with the multivariate normal distribution. For example, the matrix t-distribution is the compound distribution that results from sampling from a matrix normal distribution having sampled the covariance matrix of the matrix normal from an inverse Wishart distribution.
In a Bayesian analysis of a multivariate linear regression model based on the matrix normal distribution, the matrix t-distribution is the posterior predictive distribution.
Definition
For a matrix t-distribution, the probability density function at the point of an space is
where the constant of integration K is given by
Here is the multivariate gamma function.
The characteristic function and various other properties can be derived from the generalized matrix t-distribution (see below).
Generalized matrix t-distribution
The generalized matrix t-distribution is a generalization of the matrix t-distribution with two parameters α and β in place of ν.
This reduces to the standard matrix t-distribution with
The generalized matrix t-distribution is the compound distribution that results from an infinite mixture of a matrix normal distribution with an inverse multivariate gamma distribution placed over either of its covariance matrices.
Properties
If then
The property above comes from Sylvester's determinant theorem:
If and and are nonsingular matrices then
The characteristic function is
where
and where is the type-two Bessel function of Herz of a matrix argument.
See also
Multivariate t-distribution
Matrix normal distribution
Notes
External links
A C++ library for random matrix generator
Random matrices
Multivariate continuous distributions |
https://en.wikipedia.org/wiki/Rechargeable%20battery | A rechargeable battery, storage battery, or secondary cell (formally a type of energy accumulator), is a type of electrical battery which can be charged, discharged into a load, and recharged many times, as opposed to a disposable or primary battery, which is supplied fully charged and discarded after use. It is composed of one or more electrochemical cells. The term "accumulator" is used as it accumulates and stores energy through a reversible electrochemical reaction. Rechargeable batteries are produced in many different shapes and sizes, ranging from button cells to megawatt systems connected to stabilize an electrical distribution network. Several different combinations of electrode materials and electrolytes are used, including lead–acid, zinc–air, nickel–cadmium (NiCd), nickel–metal hydride (NiMH), lithium-ion (Li-ion), lithium iron phosphate (LiFePO4), and lithium-ion polymer (Li-ion polymer).
Rechargeable batteries typically initially cost more than disposable batteries but have a much lower total cost of ownership and environmental impact, as they can be recharged inexpensively many times before they need replacing. Some rechargeable battery types are available in the same sizes and voltages as disposable types, and can be used interchangeably with them. Billions of dollars in research are being invested around the world for improving batteries and industry also focuses on building better batteries. Some characteristics of rechargeable battery are given below:
In rechargeable batteries, energy is induced by applying an external source to the chemical substances.
The chemical reaction that occurs in them is reversible.
Internal resistance is comparatively low.
They have a high self-discharge rate comparatively.
They have a bulky and complex design.
They have high resell value.
Applications
Devices which use rechargeable batteries include automobile starters, portable consumer devices, light vehicles (such as motorized wheelchairs, golf carts, e |
https://en.wikipedia.org/wiki/Cardiovascular%20fitness | Cardiovascular fitness refers a health-related component of physical fitness that is brought about by sustained physical activity. A person's ability to deliver oxygen to the working muscles is affected by many physiological parameters, including heart rate, stroke volume, cardiac output, and maximal oxygen consumption.
Understanding the relationship between cardiorespiratory fitness and other categories of conditioning requires a review of changes that occur with increased aerobic, or anaerobic capacity. As aerobic/anaerobic capacity increases, general metabolism rises, muscle metabolism is enhanced, haemoglobin rises, buffers in the bloodstream increase, venous return is improved, stroke volume is improved, and the blood bed becomes more able to adapt readily to varying demands. Each of these results of cardiovascular fitness/cardiorespiratory conditioning will have a direct positive effect on muscular endurance, and an indirect effect on strength and flexibility.
To facilitate optimal delivery of oxygen to the working muscles, an individual needs to train or participate in activities that will build up the energy stores needed for sport. This is referred to as metabolic training. Metabolic training is generally divided into two types: aerobic and anaerobic. A 2005 Cochrane review demonstrated that physical activity interventions are effective for increasing cardiovascular fitness.
Cardiovascular fitness is a measure of how well the heart, lungs, and blood vessels can transport oxygen to the muscles during exercise. It is an important component of overall fitness and has been linked to numerous health benefits, including a reduced risk of cardiovascular disease, improved cognitive function, and increased longevity. A study published in the American Journal of Epidemiology found that higher levels of cardiovascular fitness were associated with a lower risk of mortality from all causes, including cardiovascular disease and cancer.
A cardiovascular workout consi |
https://en.wikipedia.org/wiki/Penis%20fencing |
Penis fencing is a mating behavior engaged in by many species of flatworm, such as Pseudobiceros hancockanus. Species which engage in the practice are hermaphroditic; each individual has both egg-producing ovaries and sperm-producing testes.
The flatworms "fence" using extendable two-headed dagger-like stylets. These stylets are pointed (and in some species hooked) in order to pierce their mate's epidermis and inject sperm into the haemocoel in an act known as intradermal hypodermic insemination, or traumatic insemination. Pairs can either compete, with only one individual transferring sperm to the other, or the pair can transfer sperm bilaterally. Both forms of sperm transfer can occur in the same species, depending on various factors.
Unilateral sperm transfer
One organism will inseminate the other, with the inseminating individual acting as the "father". The sperm is absorbed through pores or sometimes wounds in the skin from the partner's stylet, causing fertilization in the other, who becomes the "mother". The battle may last for up to an hour in some species.
Parturition, while necessary for successful offspring production, requires a considerable parental investment in time and energy, and according to Bateman's principle, almost always burdens the "mother". Thus, from an optimality model it is usually preferable for an organism to inseminate than to be inseminated. However, in many species that engage in this form of copulatory competition, each "father" will continue to fence with other partners until it is inseminated. In Alderia modesta, individuals will store sperm from several "fencing matches" before laying their eggs, and smaller individuals will more often inseminate a larger partner, with larger individuals spending more energy on laying eggs when paired with a smaller partner on the occasion that they transfer sperm unilaterally.
In the absence of potential mates, some species such as Neobenedenia melleni are capable of reproducing thr |
https://en.wikipedia.org/wiki/Cassius%20Ionescu-Tulcea | Cassius Tocqueville Ionescu Tulcea (; October 14, 1923 – March 6, 2021) was a Romanian-American mathematician, specializing in probability theory, statistics and mathematical analysis.
Ionescu Tulcea was born in October 1923 in Bucharest. He received his diploma from the University of Bucharest in 1946; there he was an assistant professor from 1946 to 1950, a lecturer from 1950 to 1951, and an associate professor from 1952 to 1957. Additionally, from 1949 to 1957 he was a researcher at the Institute of Mathematics of the Romanian Academy. In 1957 he moved to the United States with his wife Alexandra Ionescu Tulcea (née Bagdasar), who had been his student. From 1957 to 1961 he worked as a research associate and visiting lecturer at Yale University. He received his doctorate from Yale in 1959 under the supervision of Einar Hille with thesis Semi-groups of Operators. Cassius Ionescu Tulcea was from 1959 to 1961 a visiting professor at Yale University, from 1961 to 1964 an associate professor at the University of Pennsylvania, and from 1964 to 1966 a full professor at the University of Illinois at Urbana–Champaign. He became in 1966 a full professor at Northwestern University and retired from there as professor emeritus.
His marriage to Alexandra Ionescu Tulcea lasted from 1956 to 1969 when they divorced. During their marriage, the two mathematicians wrote a number of papers together, as well as a well-regarded research monograph on lifting theory. John von Neumann initiated lifting theory in functional analysis with applications in probability theory. The Ionescu-Tulcea theorem, an important existence theorem for time-discrete stochastic processes, is named after Cassius Ionescu Tulcea (1949). He also did research on mathematical game theory and mathematical economics. He co-authored a book on casino gambling and several textbooks on mathematics; he also wrote a 1981 book on casino dice games and gambling systems and a 1982 book on casino blackjack.
In 1957 he was |
https://en.wikipedia.org/wiki/Coordinate%20time | In the theory of relativity, it is convenient to express results in terms of a spacetime coordinate system relative to an implied observer. In many (but not all) coordinate systems, an event is specified by one time coordinate and three spatial coordinates. The time specified by the time coordinate is referred to as coordinate time to distinguish it from proper time.
In the special case of an inertial observer in special relativity, by convention the coordinate time at an event is the same as the proper time measured by a clock that is at the same location as the event, that is stationary relative to the observer and that has been synchronised to the observer's clock using the Einstein synchronisation convention.
Coordinate time, proper time, and clock synchronization
A fuller explanation of the concept of coordinate time arises from its relations with proper time and with clock synchronization. Synchronization, along with the related concept of simultaneity, has to receive careful definition in the framework of general relativity theory, because many of the assumptions inherent in classical mechanics and classical accounts of space and time had to be removed. Specific clock synchronization procedures were defined by Einstein and give rise to a limited concept of simultaneity.
Two events are called simultaneous in a chosen reference frame if and only if the chosen coordinate time has the same value for both of them; and this condition allows for the physical possibility and likelihood that they will not be simultaneous from the standpoint of another reference frame.
But outside special relativity, the coordinate time is not a time that could be measured by a clock located at the place that nominally defines the reference frame, e.g. a clock located at the solar system barycenter would not measure the coordinate time of the barycentric reference frame, and a clock located at the geocenter would not measure the coordinate time of a geocentric reference fra |
https://en.wikipedia.org/wiki/Video%20game%20preservation | Video game preservation is a form of preservation applied to the video game industry that includes, but is not limited to, digital preservation. Such preservation efforts include archiving development source code and art assets, digital copies of video games, emulation of video game hardware, maintenance and preservation of specialized video game hardware such as arcade games and video game consoles, and digitization of print video game magazines and books prior to the Digital Revolution.
Importance of preservation
Besides retaining the ability to play games from the past, preservation of video games enables research on the history of video games as well as ways for developers to look at older games to build ideas from. There is also interest in the preservation of cancelled video games that were known to be in development, as coupled with the reasons for cancellation, they can provide an understanding of the technical and creative aspects, or lack thereof, at the time of the game's development.
Unlike some examples of other forms of media like books, art and photography, and film, which antedate the mid-20th century and which can be preserved in a variety of formats that are not prohibited by more-recent intellectual property (IP) laws, video games typically require specialized and/or proprietary computer hardware and software to read and execute game software. However, as technology advances, these older game systems become obsolete, no longer produced nor maintained to use for executing games. The media formats of the early days of computer gaming, relying on floppy discs and CD-ROMs, suffer from disc rot and degrade over time, making it difficult to recover information. Further, video games tend to rely on other resources like operating systems, network connectivity, and external servers outside control of users, and making sure these boundary aspects to a video game are preserved along with the game are also essential. B
According to a 2023 study by the Vide |
https://en.wikipedia.org/wiki/Digital%20loop%20carrier | A digital loop carrier (DLC) is a system which uses digital transmission to extend the range of the local loop farther than would be possible using only twisted pair copper wires. A DLC digitizes and multiplexes the individual signals carried by the local loops onto a single datastream on the DLC segment.
Reasons for using DLCs
Subscriber Loop Carrier systems address a number of problems:
Electrical constraints on long loops.
Insufficient available cable pairs.
Cable route congestion (inability to add cable due to lack of space, particularly in urban street, bridge, and building conduit)
Construction challenges (in areas of difficult terrain) when limited cable pairs are already available
Expense due to cable cost and the associated labour-intensive installation work (especially to solve the specific problems listed above)
Long loops, such as those terminating at more than 18,000 feet (5.49 kilometres) from the central office, pose
electrical challenges. When the subscriber goes off-hook, a cable pair behaves like a single loop
inductance coil with a -48 V dc potential and an Electric current of between 20–50 mA dc. Electric current values vary with cable length and gauge. A minimum current of around 20 mA dc is required to convey terminal signalling information to the network. There is also a minimum power level required to provide adequate volume for the voice signal. A variety of schemes were implemented before DLC technology to offset the impedance long loops offered to signalling and volume levels. They included the following:
Use heavy-gauge conductors – Up to 19 gauge (approximately the gauge of pencil lead), which is costly and bulky. The heavy-gauge cables yielded far fewer pairs per cable and led to early congestion in cable routes, especially in bridge crossings and other areas of limited space.
Increase battery voltage – This violation of operating standards could pose a safety hazard.
Add amplifiers to power the voice signal on long loops. This requi |
https://en.wikipedia.org/wiki/Slaframine | Slaframine is an bicyclic alkaloid mycotoxin that generally causes salivation (slobbers) in most animals. It is usually produced by the fungus Rhizoctonia leguminicola. It is a common fungal pathogen of red clover (Trifolium pratense) that causes black patch disease in the plant. Slaframine has the molecular formula C10H18N2O2. The different environmental condition promotes the growth of the Rhizoctonia leguminicola fungus. For example, wet and humid weather are the favorable environmental condition for the growth of the fungus and production of slaframine. Legume hays contaminated with slaframine causes slobber syndrome and the various animals are sensitive to its effects.
History
In the late 1940s and 1950s in Midwestern United States, various agricultural experiment stations revealed the outbreaks of salivation in the cattle. In 1956, the first case of fungal contamination of red clover with Rhizoctonia leguminicola was reported which was mainly associated with a pasture disease called black patch. This was so called because it derives its name from the appearance of affected areas in the field. Most of these cases were associated with the feeding of second-cutting red clover hay. Another serious outbreak of slobbers occurred in a herd of horses in the fall of 1979 near High Point, North Carolina. This was caused by a shipment of high-quality second-cutting red clover-orchard grass hay from a usual supplier in West Virginia. In 2010, the slaframine toxin, or "slobber toxin" was also observed in Central Kentucky because of the wet spring weather and abundant clover growth.
Metabolism
Liver is the major site of slaframine metabolism where it has been suggested that slaframine is metabolized in the liver by a microsomal flavoprotein oxidase to the active metabolite consisting of a quaternary nitrogen separated from an acetate ester by two carbon atoms.
It is apparent to reveal that the more direct access to hepatic tissues provided by the route of administration, |
https://en.wikipedia.org/wiki/Linear%20motion | Linear motion, also called rectilinear motion, is one-dimensional motion along a straight line, and can therefore be described mathematically using only one spatial dimension. The linear motion can be of two types: uniform linear motion, with constant velocity (zero acceleration); and non-uniform linear motion, with variable velocity (non-zero acceleration). The motion of a particle (a point-like object) along a line can be described by its position , which varies with (time). An example of linear motion is an athlete running a 100-meter dash along a straight track.
Linear motion is the most basic of all motion. According to Newton's first law of motion, objects that do not experience any net force will continue to move in a straight line with a constant velocity until they are subjected to a net force. Under everyday circumstances, external forces such as gravity and friction can cause an object to change the direction of its motion, so that its motion cannot be described as linear.
One may compare linear motion to general motion. In general motion, a particle's position and velocity are described by vectors, which have a magnitude and direction. In linear motion, the directions of all the vectors describing the system are equal and constant which means the objects move along the same axis and do not change direction. The analysis of such systems may therefore be simplified by neglecting the direction components of the vectors involved and dealing only with the magnitude.
Background
Displacement
The motion in which all the particles of a body move through the same distance in the same time is called translatory motion. There are two types of translatory motions: rectilinear motion; curvilinear motion. Since linear motion is a motion in a single dimension, the distance traveled by an object in particular direction is the same as displacement. The SI unit of displacement is the metre. If is the initial position of an object and is the final position, then mat |
https://en.wikipedia.org/wiki/List%20of%20refractive%20indices | Many materials have a well-characterized refractive index, but these indices often depend strongly upon the frequency of light, causing optical dispersion. Standard refractive index measurements are taken at the "yellow doublet" sodium D line, with a wavelength (λ) of 589 nanometers.
There are also weaker dependencies on temperature, pressure/stress, etc., as well on precise material compositions (presence of dopants, etc.); for many materials and typical conditions, however, these variations are at the percent level or less. Thus, it is especially important to cite the source for an index measurement if precision is required.
In general, an index of refraction is a complex number with both a real and imaginary part, where the latter indicates the strength of absorption loss at a particular wavelength—thus, the imaginary part is sometimes called the extinction coefficient . Such losses become particularly significant, for example, in metals at short (e.g. visible) wavelengths, and must be included in any description of the refractive index.
List
See also
Sellmeier equation
Corrective lens#Ophthalmic material property tables
Optical properties of water and ice |
https://en.wikipedia.org/wiki/Dan%20Archdeacon | Dan Steven Archdeacon (1954–2015) was an American graph theorist specializing in topological graph theory, who served for many years as a professor of mathematics and statistics at the University of Vermont.
Archdeacon was born on May 11, 1954, in Dayton, Ohio, and grew up in Centerville, Ohio.
He did his undergraduate studies at Earlham College, graduating in 1975.
He completed his Ph.D. in 1980 from Ohio State University, under the supervision of Henry Hatfield Glover, with a dissertation proving an analogue of Kuratowski's theorem for the projective plane. He took a position at the University of Vermont in 1982, joining fellow graph theorist and Ohio State graduate Jeff Dinitz, after previously working as an instructor at the University of Kansas.
He died of cancer on February 18, 2015, in Burlington, Vermont.
In 2003–2004, the University of Vermont named him as University Scholar.
A special issue of the Australasian Journal of Combinatorics was published in his honor in 2017. |
https://en.wikipedia.org/wiki/IMPLY%20gate | The IMPLY gate is a digital logic gate that implements a logical conditional.
Symbols
There are two symbols for IMPLY gates: the traditional symbol and the IEEE symbol. For more information see Logic gate symbols.
The logic symbol → can be used to denote IMPLY in algebraic expressions.
See also
NIMPLY gate
AND gate
NOT gate
NAND gate
NOR gate
XOR gate
XNOR gate
Boolean algebra (logic)
Logic gates
Logic gates |
https://en.wikipedia.org/wiki/Heat%20exchanger | A heat exchanger is a system used to transfer heat between a source and a working fluid. Heat exchangers are used in both cooling and heating processes. The fluids may be separated by a solid wall to prevent mixing or they may be in direct contact. They are widely used in space heating, refrigeration, air conditioning, power stations, chemical plants, petrochemical plants, petroleum refineries, natural-gas processing, and sewage treatment. The classic example of a heat exchanger is found in an internal combustion engine in which a circulating fluid known as engine coolant flows through radiator coils and air flows past the coils, which cools the coolant and heats the incoming air. Another example is the heat sink, which is a passive heat exchanger that transfers the heat generated by an electronic or a mechanical device to a fluid medium, often air or a liquid coolant.
Flow arrangement
There are three primary classifications of heat exchangers according to their flow arrangement. In parallel-flow heat exchangers, the two fluids enter the exchanger at the same end, and travel in parallel to one another to the other side. In counter-flow heat exchangers the fluids enter the exchanger from opposite ends. The counter current design is the most efficient, in that it can transfer the most heat from the heat (transfer) medium per unit mass due to the fact that the average temperature difference along any unit length is higher. See countercurrent exchange. In a cross-flow heat exchanger, the fluids travel roughly perpendicular to one another through the exchanger.
For efficiency, heat exchangers are designed to maximize the surface area of the wall between the two fluids, while minimizing resistance to fluid flow through the exchanger. The exchanger's performance can also be affected by the addition of fins or corrugations in one or both directions, which increase surface area and may channel fluid flow or induce turbulence.
The driving temperature across the heat trans |
https://en.wikipedia.org/wiki/Solar%20lamp | A solar lamp, also known as a solar light or solar lantern, is a lighting system composed of an LED lamp, solar panels, battery, charge controller and there may also be an inverter. The lamp operates on electricity from batteries, charged through the use of solar panel (solar photovoltaic panel)
Solar-powered household lighting can replace other light sources like candles or kerosene lamps. Solar lamps have a lower operating cost than kerosene lamps because renewable energy from the sun is free, unlike fuel. In addition, solar lamps produce no indoor air pollution unlike kerosene lamps. However, solar lamps generally have a higher initial cost, and are weather dependent.
Solar lamps for use in rural situations often have the capability of providing a supply of electricity for other devices, such as for charging cell phones. The costs of solar lamps have continued to fall in recent years as the components and lamps have been mass-produced in ever greater numbers.
History
Some solar photovoltaics use Monocrystalline silicon or poly-crystalline silicon panels, while newer technologies have used thin-film solar cells. Since modern solar cells were introduced in 1954 at Bell labs, advances in solar cell efficiency at converting light into electric power, and modern manufacturing techniques combined with efficiencies of scale have led to an international growth of photovoltaics.
The first solar light patent was filed by Maurice E Paradise in 1955
As of 2016, LED lamps use only about 10% of the energy an incandescent lamp requires. Efficiency in production of LED lamps has led to increased adoption as an alternative to older electric lightings
Components
The complete structure of a solar lamp is shown in Figure 1.
Solar panels
Most solar panels are made out of single crystalline silicon, a semiconductor material.
When light strikes a solar cell, an electric current is produced in the connected electric circuit. This is called the photoelectric effect. Photovol |
https://en.wikipedia.org/wiki/Connectedness%20locus | In one-dimensional complex dynamics, the connectedness locus of a parameterized family of one-variable holomorphic functions is a subset of the parameter space which consists of those parameters for which the corresponding Julia set is connected.
Examples
Without doubt, the most famous connectedness locus is the Mandelbrot set, which arises from the family of complex quadratic polynomials :
The connectedness loci of the higher-degree unicritical families,
(where ) are often called 'Multibrot sets'.
For these families, the bifurcation locus is the boundary of the connectedness locus. This is no longer true in settings, such as the full parameter space of cubic polynomials, where there is more than one free critical point. For these families, even maps with disconnected Julia sets may display nontrivial dynamics. Hence here the connectedness locus is generally of less interest.
External links
Complex analysis
Fractals |
https://en.wikipedia.org/wiki/Computational%20linguistics | Computational linguistics is an interdisciplinary field concerned with the computational modelling of natural language, as well as the study of appropriate computational approaches to linguistic questions. In general, computational linguistics draws upon linguistics, computer science, artificial intelligence, mathematics, logic, philosophy, cognitive science, cognitive psychology, psycholinguistics, anthropology and neuroscience, among others.
Since the 2020s, computational linguistics has become a near-synonym of either natural language processing or language technology, with deep learning approaches, such as large language models, outperforming the specific approaches previously used in the field.
Origins
The field overlapped with artificial intelligence since the efforts in the United States in the 1950s to use computers to automatically translate texts from foreign languages, particularly Russian scientific journals, into English. Since rule-based approaches were able to make arithmetic (systematic) calculations much faster and more accurately than humans, it was expected that lexicon, morphology, syntax and semantics can be learned using explicit rules, as well. After the failure of rule-based approaches, David Hays coined the term in order to distinguish the field from AI and co-founded both the Association for Computational Linguistics (ACL) and the International Committee on Computational Linguistics (ICCL) in the 1970s and 1980s. What started as an effort to translate between languages evolved into a much wider field of natural language processing.
Annotated corpora
In order to be able to meticulously study the English language, an annotated text corpus was much needed. The Penn Treebank was one of the most used corpora. It consisted of IBM computer manuals, transcribed telephone conversations, and other texts, together containing over 4.5 million words of American English, annotated using both part-of-speech tagging and syntactic bracketing.
Japanese |
https://en.wikipedia.org/wiki/Trellix | Trellix (formerly FireEye and McAfee Enterprise) is a privately held cybersecurity company that was founded in 2022. It has been involved in the detection and prevention of major cybersecurity attacks.
It provides hardware, software, and services to investigate cybersecurity attacks, protect against malicious software, and analyze IT security risks.
In March 2021, Symphony Technology Group (STG) announced its acquisition of McAfee Enterprise in an all-cash transaction for US$4.0 billion. STG completed the acquisition of McAfee’s Enterprise business in July 2021 with plans for re-branding. In June 2021, FireEye sold its name and products business to STG for $1.2bn. STG combined FireEye with its acquisition of McAfee's enterprise business to launch Trellix, an extended detection and response (XDR) company. Meanwhile, McAfee Enterprise's security service edge (SSE) business would operate as a separate company to be known as Skyhigh Security.
History
FireEye was founded in 2004 by Ashar Aziz, a former Sun Microsystems engineer. FireEye's first commercial product was not developed and sold until 2010. That same year, FireEye expanded into the Middle East. This was followed by the opening of new offices in the Asia Pacific in 2010, Europe in 2011 and Africa in 2013.
Initially, FireEye focused on developing virtual machines to download and test internet traffic before transferring it to a corporate or government network. The company diversified over time, in part through acquisitions.
In December 2012, founder Aziz stepped down as CEO and former McAfee CEO David DeWalt was appointed to the position. DeWalt was recruited to prepare the company for an initial public offering (IPO). The following year, FireEye raised an additional $50 million in venture capital, bringing its total funding to $85M. In late 2013, FireEye went public, raising $300M. FireEye remained public until 2021.
At the time, FireEye was growing rapidly. It had 175 employees in 2011, which grew to 900 |
https://en.wikipedia.org/wiki/Reversion%20%28software%20development%29 | In software development (and, by extension, in content-editing environments, especially wikis, that make use of the software development process of revision control), reversion or reverting is the abandonment of one or more recent changes in favor of a return to a previous version of the material at hand (typically software source code in the context of application development; HTML, CSS or script code in the context of web development; or content and formatting thereof in the context of wikis).
A revert may be done for a wide variety of reasons, including: fixing errors introduced by previous edits; restoring the material to a state that was not contentious until new disputes can be resolved; undoing scope creep; regression testing; and even petty malice, vandalistic intent, or personal unhappiness with the author of a previous change. While the is generally agreed to be a sound and sometimes necessary one, particular instantiations of its use may be at least as controversial as the changes being reverted.
See also
Revision control
Sandbox (computer security)
Software development process |
https://en.wikipedia.org/wiki/Nicaragua%20lunar%20sample%20displays | The Nicaraguan lunar sample displays are two commemorative plaques consisting of small fragments of Moon specimen brought back with the Apollo 11 and Apollo 17 Moon missions and given in the 1970s to the people of Nicaragua by United States President Richard Nixon as goodwill gifts.
Description
Apollo 11
Apollo 17
History
The Nicaragua Apollo 11 lunar plaque display was reported stolen, but was returned to Nicaragua in 2012.
See also
List of Apollo lunar sample displays |
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