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  • experimental meteorology (science)

    Vincent Joseph Schaefer: …snow, initiating the science of experimental meteorology and weather control.

  • experimental method

    climate classification: Empirical classifications: Most empirical classifications are those that seek to group climates based on one or more aspects of the climate system. While many such phenomena have been used in this way, natural vegetation stands out as one of prime importance. The view held by…

  • experimental method

    Scientific method, mathematical and experimental technique employed in the sciences. More specifically, it is the technique used in the construction and testing of a scientific hypothesis. The process of observing, asking questions, and seeking answers through tests and experiments is not unique to

  • Experimental Novel, The (work by Zola)

    philosophy of art: Analysis of representation: …book Le Roman expérimental (1880; The Experimental Novel) and has been occasionally held (though not practiced) by painters reacting against Romanticism, such as the 19th-century French artist Gustave Courbet. Zola advocated a novel that resembled a scientific investigation into reality. Plot was to be of no importance, rather an aspect…

  • experimental petrology (geology)

    petrology: Petrology includes the subdisciplines of experimental petrology and petrography. Experimental petrology involves the laboratory synthesis of rocks for the purpose of ascertaining the physical and chemical conditions under which rock formation occurs. Petrography is the study of rocks in thin section by means of a petrographic microscope (i.e., an instrument…

  • Experimental Prototype Community of Tomorrow (theme park, Florida, United States)

    Epcot, theme park in the Walt Disney World Resort, near Orlando, Fla., that features many attractions centred on the advancement of technology. As Walt Disney initially imagined it, Epcot was to be a self-contained city that would incorporate the newest technologies. Following Disney’s death in

  • experimental psychology

    Experimental psychology, a method of studying psychological phenomena and processes. The experimental method in psychology attempts to account for the activities of animals (including humans) and the functional organization of mental processes by manipulating variables that may give rise to

  • Experimental Psychology (work by Titchener)

    Edward B. Titchener: …far the most important was Experimental Psychology, 4 vol. (1901–05), consisting of two student manuals and two teachers’ manuals. Designed to drill students in laboratory method, the manuals were patterned on those used in qualitative and quantitative experiments in chemistry.

  • experimental school

    education: Progressive education: …ideas into practice to establish experimental schools during the last decade of the 19th century and in the early 20th century. The principal experimental schools in America until 1914 were the University of Chicago Laboratory School, founded in 1896 and directed by John Dewey; the Francis W. Parker School, founded…

  • experimental science (science)

    Western philosophy: Robert Grosseteste and Roger Bacon: The term experimental science was popularized in the West through his writings. For him, human beings acquire knowledge through reasoning and experience, but without the latter there can be no certitude. Humans gain experience through the senses and also through an interior divine illumination that culminates in…

  • experimental taxonomy (botany)

    Frederic Edward Clements: …new lines of research, notably experimental taxonomy. For Clements, experimental taxonomy meant using transplant experiments and other ecological methods to investigate evolutionary processes and to improve the classification of plants. Together with American botanist Harvey Monroe Hall, Clements wrote an influential introduction to this interdisciplinary area of research, The Phylogenetic…

  • Experimental Theatre (Ghanaian theatrical group)

    Efua Sutherland: …Experimental Theatre, which became the Ghana Drama Studio, and directed the University of Ghana’s traveling theatre group. The Drama Studio produced a number of her plays, including the well-known Foriwa (1962), a play which stresses the alliance of new ways and old traditions, and Edufa (1967), based on Alcestis by…

  • experimental unit (statistics)

    statistics: Experimental design: …is referred to as an experimental unit, the response variable is the cholesterol level of the patient at the completion of the program, and the exercise program is the factor whose effect on cholesterol level is being investigated. Each of the three exercise programs is referred to as a treatment.

  • experimentalism (philosophy)

    Instrumentalism, in the philosophy of science, the view that the value of scientific concepts and theories is determined not by whether they are literally true or correspond to reality in some sense but by the extent to which they help to make accurate empirical predictions or to resolve conceptual

  • experimentation (science)

    biology: The history of biology: …test the hypotheses by appropriate experiments. The most original and inquiring mind is severely limited without the proper tools to conduct an investigation; conversely, the most-sophisticated technological equipment cannot of itself yield insights into any scientific process.

  • experimentation (art)

    Western literature: The 20th century: …difficult to judge, that radical experimentation characterized many fields of literature, and that traditional forms of writing were losing their definition and were tending to dissolve into one another. Novels might acquire many features of poetry or be transformed into a kind of heightened nonfictional reportage, while experimentation with typography…

  • Experiments and Observations on Electricity (work by Franklin)

    Benjamin Franklin: Achievement of security and fame (1726–53): …in an 86-page book titled Experiments and Observations on Electricity. In the 18th century the book went through five English editions, three in French, and one each in Italian and German.

  • Experiments Concerning Animal Gerneration (work by Harvey)

    William Harvey: Later life: …Exercitationes de Generatione Animalium (Exercises on the Generation of Animals), it is believed that Harvey attempted to take his own life with laudanum (an alcoholic tincture of opium). However, this attempt failed. On June 3, 1657, at the age of 79, he died of a stroke.

  • Experiments in Hearing (work by Békésy)

    acoustics: Modern advances: Békésy’s book Experiments in Hearing, published in 1960, is the magnum opus of the modern theory of the ear.

  • Experiments in Intergroup Discrimination (work by Tajfel)

    Henri Tajfel: Perceptual accentuation: …revealed in a 1970 paper, “Experiments in Intergroup Discrimination,” in which he explored the concept of social categorization (the classification of people as members of social groups) as a basis for intergroup discrimination (discrimination by members of one group against members of another group). In contrast to realistic group-conflict theory,…

  • Experiments on Mass Communication (work by Hovland)

    Carl I. Hovland: …work formed the basis for Experiments on Mass Communication (1949), with Arthur A. Lumsdaine and Fred D. Sheffield as coauthors.

  • Experiments Upon Magnesia Alba, Quicklime, and Some Other Alcaline Substances (work by Black)

    Joseph Black: Alkalinity research and fixed air: …paper of his career, “Experiments upon Magnesia Alba, Quicklime, and Some Other Alcaline Substances,” given to the Philosophical Society of Edinburgh in 1755. The earlier series of experiments for his thesis were conducted on magnesium salt and, for the first time, consisted of a planned cyclic series of quantitative…

  • Experiments with Plant Hybrids (article by Mendel)

    Gregor Mendel: Theoretical interpretation: His paper “Experiments on Plant Hybrids” was published in the society’s journal, Verhandlungen des naturforschenden Vereines in Brünn, the following year. It attracted little attention, although many libraries received it and reprints were sent out. The tendency of those who read it was to conclude that Mendel…

  • expert evidence (law)

    evidence: Expert evidence: Expert witnesses must have specialized knowledge, skill, or experience in the area of their testimony. For the most part, they do not testify concerning facts but draw inferences from them. With a few exceptions, they are treated in Anglo-American law as ordinary witnesses…

  • expert system (computer science)

    Expert system, a computer program that uses artificial-intelligence methods to solve problems within a specialized domain that ordinarily requires human expertise. The first expert system was developed in 1965 by Edward Feigenbaum and Joshua Lederberg of Stanford University in California, U.S.

  • expert thinking (psychology)

    thought: Expert thinking and novice thinking: Research by the American psychologists Herbert A. Simon, Robert Glaser, and Micheline Chi, among others, has shown that experts and novices think and solve problems in somewhat different ways. These differences explain why experts are more effective than novices in…

  • Experts for the Assessment of Overall Economic Trends, Board of (German economic group)

    Germany: Economy: The Board of Experts for the Assessment of Overall Economic Trends, established in 1963 and known as the “five wise men,” produces an evaluation of overall economic developments each year to assist in national economic decision making. Moreover, the federal government submits an annual economic report…

  • Experts, Assembly of (Iranian government)

    Iran: Deliberative bodies: The Assembly of Experts, a body of 83 clerics, was originally formed to draft the 1979 constitution. Since that time its sole function has been to select a new leader in the event of the death or incapacitation of the incumbent. If a suitable candidate is…

  • Experts, The (painting by Decamps)

    Alexandre Decamps: …of all his works is The Experts (c. 1837), a clever satire of the jury of the Académie des Beaux-Arts, which had rejected several of his earlier works.

  • expiation (penology)

    punishment: Retribution: …punishment is a kind of expiation: offenders should undergo punishment in their own interests to discharge their guilt and to make themselves acceptable to society again.

  • expiration (physiology)

    speech: Respiratory mechanisms: …inhalation (inspiration) and exhalation (expiration). Inspiration and expiration are equally long, equally deep, and transport the same amount of air during the same period of time, approximately half a litre (one pint) of air per breath at rest in most adults. Recordings (made with a device called a pneumograph)…

  • explanation (philosophy)

    Explanation, in philosophy, set of statements that makes intelligible the existence or occurrence of an object, event, or state of affairs. Among the most common forms of explanation are causal explanation (see causation); deductive-nomological explanation (see covering-law model), which involves

  • Explanation of the Effect of Lime upon Alkaline Salts, An (work by Black)

    Joseph Black: Industrial consultant: …concerning an industrial process, “An Explanation of the Effect of Lime upon Alkaline Salts,” which was published in Home’s Experiments on Bleaching (1771). Another approach to the bleaching problem was to look for a cheaper way of making potash. Cullen turned his mind to this and was rewarded by…

  • Explanation of the Grand Mystery of Godliness, An (work by More)

    Henry More: …views, most fully expressed in An Explanation of the Grand Mystery of Godliness (1660) and Divine Dialogues (1668), centred on his idea of reconciling Christian Platonism with 17th-century science. His ethical writings include Enchiridion Ethicum (1667); his work An Antidote against Atheism (1652) is curiously devoted, in large part, to…

  • Explanation, Act of (England [1665])

    Ireland: The Restoration period and the Jacobite war: The Act of Explanation (1665) obliged the Cromwellian settlers to surrender one-third of their grants and thus provided a reserve of land from which Roman Catholics were partially compensated for losses under the Commonwealth. This satisfied neither group. Catholics were prevented from residing in towns, and…

  • Explanatory Diagram on the Garland World System, An (work by ?isang)

    ?isang: …he wrote his major work, An Explanatory Diagram on the Garland World System, which elicited high acclaim from his master and is still read widely in the Buddhist circles of East Asia. On returning home in 671, he built, sponsored by King Munmu, the Pus?k Temple as the centre of…

  • explication de texte (literary criticism)

    Explication de texte, (French: “explanation of text”) a method of literary criticism involving a detailed examination of each part of a work, such as structure, style, and imagery, and an exposition of the relationship of these parts to each other and to the whole work. The method was originally

  • Explication des maximes des saints sur la vie intérieure (work by Fénelon)

    Fran?ois de Salignac de La Mothe-Fénelon: …Mme Guyon, Fénelon responded with Explication des maximes des saints sur la vie intérieure (1697; “Explanation of the Sayings of the Saints on the Interior Life”). Defending Mme Guyon’s integrity, Fénelon not only lost Bossuet’s friendship but also exposed himself to Bossuet’s public denunciation. As a result, Fénelon’s Maximes des…

  • explicit (publishing)

    Explicit, in bookmaking, a device added to the end of some manuscripts and incunabula by the author or scribe and providing such information as the title of the work and the name or initials of its author or scribe. Explicits were soon incorporated into or completely replaced by the colophon, which

  • explicit plea bargaining (law)

    plea bargaining: …formal agreements are termed “explicit plea bargains.” However, some plea bargains are called “implicit plea bargains” because they involve no guarantee of leniency. Explicit bargains are the more important of the two.

  • exploded lek (bird courtship)

    manakin: In others, called exploded leks, males are separated by much larger distances (sometimes up to several hundred metres), and females must wander from one male to another to choose their mates. Males that form exploded leks typically have extremely loud vocalizations that ring through the forest for hundreds…

  • exploitation (economics)

    class consciousness: …instance, the experience of economic exploitation can lead workers to recognize that they have a stake in each other’s well-being, and from there they will develop class consciousness and class solidarity. Mann’s focus was placed on consciousness itself and thus departed to some extent from Marx’s attempt to embed consciousness…

  • exploitation competition (biology)

    community ecology: Types of competition: …faster than their competitors (exploitation competition). Some plant species, for example, are able to extract water and nutrients from the soil faster than surrounding species. In other cases, the two species physically interfere with one another (interference competition) by aggressively attempting to exclude one another from particular habitats.

  • Exploits of the Turks (work by al-Jā?i?)

    al-Jā?i?: …by writing essays such as Manāqib at-turk (Eng. trans., “Exploits of the Turks,” in Journal of the Royal Asiatic Society, 1915), a discussion of the military qualities of the Turkish soldiers, on whom government policy depended.

  • Explorata (work by Jonson)

    dramatic literature: Western theory: … (1595) and Ben Jonson in Timber (1640) merely attacked contemporary stage practice. Jonson, in certain prefaces, however, also developed a tested theory of comic characterization (the “humours”) that was to affect English comedy for a hundred years. The best of Neoclassical criticism in English is John Dryden’s Of Dramatick Poesie,…

  • exploration
  • Exploration du Sahara: Les Touareg du nord (work by Duveyrier)

    Henri Duveyrier: …returning to France he published Exploration du Sahara: Les Touareg du nord (1864; “Exploration of the Sahara: The Tuareg of the North”).

  • Exploration of Cosmic Space by Means of Reaction Devices (work by Tsiolkovsky)

    Konstantin Tsiolkovsky: …serious work on astronautics, “Exploration of Cosmic Space by Means of Reaction Devices,” which dealt with theoretical problems of using rocket engines in space, including heat transfer, a navigating mechanism, heating resulting from air friction, and maintenance of fuel supply.

  • exploration, overseas

    European exploration, exploration of regions of Earth for scientific, commercial, religious, military, and other purposes by Europeans, beginning about the 4th century bce. The motives that spur human beings to examine their environment are many. Strong among them are the satisfaction of curiosity,

  • Explorations in South-West Africa (work by Baines)

    Thomas Baines: …his drawings and his book Explorations in South-West Africa (1864) were based. With his fame established, he opened a studio in London in 1865. Returning to Africa in 1868, he led an expedition to explore the goldfields of Matabeleland, where in 1870 he won a mining concession from the Ndebele…

  • Exploratorium (museum, San Francisco, California, United States)

    San Francisco: Cultural institutions: Housing the Exploratorium (a science museum), the palace is a giant Neoclassical rotunda, which was designed by the architect Bernard Maybeck and completely restored in the 1960s. The Walt Disney Family Museum, celebrating the life and work of the animation pioneer, producer, and showman, was opened in…

  • exploratory data analysis (statistics)

    statistics: Exploratory data analysis: Exploratory data analysis provides a variety of tools for quickly summarizing and gaining insight about a set of data. Two such methods are the five-number summary and the box plot. A five-number summary simply consists of the smallest data value, the first…

  • exploratory surgery

    Exploratory surgery, manual and instrumental means of investigating an area of the body suspected of disease when a specific diagnosis is not possible through noninvasive or simple biopsy techniques. If the lesion is in the abdomen, exploratory surgery involves a laparotomy, or incision into the

  • Explorer (satellites)

    Explorer, any of the largest series of unmanned U.S. spacecraft, consisting of 55 scientific satellites launched between 1958 and 1975. Explorer 1 (launched Jan. 31, 1958), the first space satellite orbited by the United States, discovered the innermost of the Van Allen radiation belts, two zones

  • Explorer (Internet browser)

    Internet Explorer (IE), World Wide Web (WWW) browser and set of technologies created by Microsoft Corporation, a leading American computer software company. After being launched in 1995, Internet Explorer became one of the most popular tools for accessing the Internet. There were 11 versions

  • Explorer II (balloon)

    balloon flight: Balloons reach the stratosphere: That balloon, the Explorer II, was seven times the size of Piccard’s, but still with very similar fabric. The stress in the skin of the giant balloon was formidable, resulting in repeated failures. On one occasion the crew, this time including Maj. William E. Kepner, barely escaped by…

  • Exploring for Plants (book by Fairchild)

    David Fairchild: >Exploring for Plants (1930), an account of the Allison Vincent Armour expeditions for the USDA, and the autobiographical The World Was My Garden (1938).

  • explosion (chemical reaction)

    blast injury: … such as that following an explosion. Blast injuries may be inflicted by such waves traveling in gases, liquids, or solids. The first is exemplified by the air blast caused by bomb explosions. Underwater blasts may originate from torpedoes, mines, and depth charges. Solid blast is the effect of a pressure…

  • explosion (phonetics)

    stop: …the hold (occlusion); and the release (explosion), or opening of the air passage again. A stop differs from a fricative (q.v.) in that, with a stop, occlusion is total, rather than partial. Occlusion may occur at various places in the vocal tract from the glottis to the lips; stops are…

  • explosion (geology)

    volcano: Explosions: Massive volcanic explosions are caused by the rapid expansion of gases, which in turn can be triggered by the sudden depressurization of a shallow hydrothermal system or gas-charged magma body or by the rapid mixing of magma with groundwater. The ash, cinders, hot fragments,…

  • explosion crater (geology)

    volcano: Other volcanic structures and features: …rock type, or genesis; and explosion crater, a large circular, elongate, or horseshoe-shaped excavation with ejected debris on its rim or flanks. A somma volcano, named for Mount Somma, a ridge on the slopes of Mount Vesuvius in Italy, is a caldera partially filled by a new central cone. In…

  • Explosion in a Cathedral (work by Carpentier)

    Alejo Carpentier: …Carpentier published another historical novel, El siglo de las luces (Explosion in a Cathedral), which chronicles the impact of the French Revolution on Caribbean countries. It was very successful and there were calls to award Carpentier a Nobel Prize, something that eluded him. In his final years Carpentier turned to…

  • explosion limit (chemistry)

    combustion: The chemical reactions: …or three pressures, called the explosion limits, may correspond to one temperature. The mechanism of the reaction determines the explosion limits: the reaction can proceed only when the steps in the sequence of reactions occur faster than the terminal steps. Thus, for combustion to be initiated with light or with…

  • explosion, chemical (chemistry)

    chain reaction: So-called branching chain reactions are a form of chain reaction in which the number of chain carriers increases in each propagation. As a result the reaction accelerates very rapidly, sometimes being completed in less than 1/1,000th of a second. This condition sometimes is referred to as…

  • explosive (chemical product)

    Explosive, any substance or device that can be made to produce a volume of rapidly expanding gas in an extremely brief period. There are three fundamental types: mechanical, nuclear, and chemical. A mechanical explosive is one that depends on a physical reaction, such as overloading a container

  • explosive bonding (construction)

    explosive: Explosive bonding: Explosives are sometimes used to bond various metals to each other. For example, when silver was removed from United States coinage, much of the so-called sandwich metal that replaced it was obtained by the explosive bonding of large slabs, which were then rolled…

  • explosive charge (ammunition)

    fuse: …is usually embedded in the explosive charge. Detonating cord, also called Cordeau and Primacord, is a hollow cord filled with an explosive material. It is fired by a detonator and is capable of initiating the detonation of certain other explosives at any number of points and in any desired pattern.

  • explosive cyclogenesis (meteorology)

    cyclogenesis: Rapid extratropical cyclone development, called explosive cyclogenesis, is often associated with major winter storms and occurs when surface pressure falls by more than about 24 millibars per day.

  • Explosive D (chemical compound)

    chemical industry: Nitric acid: Another explosive ingredient is ammonium picrate, derived from picric acid, the relationship of which appears more clearly in its systematic name, 2,4,6-trinitrophenol.

  • explosive grenade (military technology)

    grenade: …commonly used in wartime are explosive grenades, which usually consist of a core of TNT or some other high explosive encased in an iron jacket or container. Such grenades have a fuse that detonates the explosive either on impact or after a brief (usually four-second) time delay that is long…

  • explosive personality disorder (psychology)

    personality disorder: Persons with explosive personality disorder exhibit extreme emotional instability characterized by explosive outbursts of rage upon minor provocation. Persons with histrionic personality disorder persistently display overly dramatic, highly excitable, and intensely expressed behaviour (i.e., histrionics). Persons with dependent personality disorder lack energy and initiative and passively let…

  • explosive reactive armour

    tank: Armour: …use, on Israeli tanks, of explosive reactive armour, which consisted of a layer of explosive sandwiched between two relatively thin steel plates. Designed to explode outward and thus neutralize the explosive penetration of a shaped-charge warhead, reactive armour augmented any protection already provided by steel or composite armour.

  • explosive rivet (building technology)

    explosive: Explosive rivets: Blind rivets are needed when space limitations make conventional rivets impractical. One type of these is explosive; it has a hollow space in the shank containing a small charge of heat-sensitive chemicals. When a suitable amount of heat is applied to the head,…

  • explosive variable star (astronomy)

    star: Explosive variables: The evolution of a member of a close double-star system can be markedly affected by the presence of its companion. As the stars age, the more massive one swells up more quickly as it moves away from the main sequence. It becomes so…

  • explosive volcanism (geology)

    volcano: Explosions: Massive volcanic explosions are caused by the rapid expansion of gases, which in turn can be triggered by the sudden depressurization of a shallow hydrothermal system or gas-charged magma body or by the rapid mixing of magma with groundwater. The ash, cinders, hot fragments,…

  • explosive welding (metallurgy)

    welding: Explosive welding: Explosive welding takes place when two plates are impacted together under an explosive force at high velocity. The lower plate is laid on a firm surface, such as a heavier steel plate. The upper plate is placed carefully at an angle of approximately…

  • explosively formed projectile (military ordnance)

    improvised explosive device: Components: …some Shī?ite militia groups used explosively formed projectiles (EFPs)—an extremely lethal form of shaped charge supplied by Iran—to destroy even the most heavily armoured vehicles, such as M1 Abrams tanks.

  • EXPO (computer science)

    virtual museum: One of the first was EXPO, which originated in 1993 with an online guide to artifacts from the Vatican Library that were on display at the U.S. Library of Congress in Washington, D.C. EXPO has been maintained since then on servers outside of the Library of Congress network and has…

  • Expo ’70 (world’s fair, ōsaka, Japan)

    graphic design: Postwar graphic design in Japan: …proposal (1967) for the Japanese World Expo ’70 in ōsaka, for example, displays his ability to combine 20th-century Modernist formal experiments with a traditional Japanese sense of harmony.

  • Expo ’85 (world’s fair, Japan)

    graphic design: Postmodern graphic design: His poster proposal (1982) for Expo ’85, an international exposition of the dwelling and construction industry, turns the letters into structural forms pulled apart to reveal their inner structures. In this way, his experimentation with form fulfilled both an aesthetic and a commercial purpose: the deconstructed forms clearly make reference…

  • Expo 2010 (world’s fair, Shanghai, China)

    Expo Shanghai 2010, world exposition in Shanghai, China, that ran between May 1 and October 31, 2010. One of the largest world fairs or expositions ever mounted, it also was the most heavily attended of any such events. Shanghai was selected as the host city of the exposition in December 2002 by

  • Expo 67 (world’s fair, Montreal, Quebec, Canada)

    Expo 67, international exposition held in 1967 in Montréal, Québec, to celebrate Canada’s centennial. Senator Mark Drouin of Québec first developed the idea of a world exhibition in Montréal to serve as a focal point for Canada’s celebrations of its 100th birthday. Drouin and senator Sarto

  • Expo 86 (world’s fair, Vancouver, British Columbia, Canada)

    Vancouver: The contemporary city: …as the Canada Pavilion for Expo 86, a nearly six-month-long world’s fair that celebrated Vancouver’s centennial in 1986 and to which more than 22 million visits were made. Adjacent to the Vancouver Convention Centre (which opened vastly expanded facilities in April 2009), it juts out into Burrard Inlet and includes…

  • Expo Memorial Park (park, Japan)

    ōsaka-Kōbe metropolitan area: Cultural life: …held near Senri New Town; Expo Memorial Park now holds the National Museum of Ethnology, the National Museum of Art, and a recreation area. ōsaka is home to Kaiyukan Aquarium, Japan’s largest.

  • Expo Shanghai 2010 (world’s fair, Shanghai, China)

    Expo Shanghai 2010, world exposition in Shanghai, China, that ran between May 1 and October 31, 2010. One of the largest world fairs or expositions ever mounted, it also was the most heavily attended of any such events. Shanghai was selected as the host city of the exposition in December 2002 by

  • exponent (mathematics)

    arithmetic: Exponents: The fundamental laws of exponents follow easily from the definitions (see the Encyclop?dia Britannica, Inc.table), and other laws are immediate consequences of the fundamental ones.

  • exponential decay (physics)

    analysis: Exponential growth and decay: This solution represents exponential decay: in any fixed period of time, the same proportion of the substance decays. This property of radioactivity is reflected in the concept of the half-life of a given radioactive substance—that is, the time taken for half the material to decay.

  • exponential decay law (physics)

    radioactivity: Exponential-decay law: Radioactive decay occurs as a statistical exponential rate process. That is to say, the number of atoms likely to decay in a given infinitesimal time interval (dN/dt) is proportional to the number (N) of atoms present. The proportionality constant, symbolized by the Greek…

  • exponential distribution (mathematics)

    probability theory: Probability density functions: The exponential distribution arises naturally in the study of the Poisson distribution introduced in equation (13). If Tk denotes the time interval between the emission of the k ? 1st and kth particle, then T1, T2,… are independent random variables having an exponential distribution with parameter…

  • exponential function (mathematics)

    Exponential function, in mathematics, a relation of the form y = ax, with the independent variable x ranging over the entire real number line as the exponent of a positive number a. Probably the most important of the exponential functions is y = ex, sometimes written y = exp (x), in which e

  • exponential growth (statistics)

    population ecology: Exponential and geometric population growth: In an ideal environment, one that has no limiting factors, populations grow at a geometric rate or an exponential rate. Human populations, in which individuals live and reproduce for many years and in which reproduction is distributed throughout the year,…

  • exponential-time algorithm

    NP-complete problem: …hand, require times that are exponential functions of the problem size n. Polynomial-time algorithms are considered to be efficient, while exponential-time algorithms are considered inefficient, because the execution times of the latter grow much more rapidly as the problem size increases.

  • export (trade)

    acceptance: Acceptances are used in financing export and import operations and in some domestic transactions involving staple commodities.

  • export credit insurance

    insurance: Export credit insurance: A special form of credit insurance is available to exporters against losses from both commercial and political risks. In the United States, for example, export credit insurance is written through a consortium of insurance companies organized by the Foreign Credit Insurance Association…

  • export duty

    tariff: Export duties: Export duties are no longer used to a great extent, except to tax certain mineral, petroleum, and agricultural products. Several resource-rich countries depend upon export duties for much of their revenue. Export duties were common in the past, however, and were significant elements…

  • Export Fluctuations, Compensatory Financing of (international finance)

    commodity trade: Interests of the less-developed countries: Compensatory financing refers to international financial assistance to a country whose export earnings have suffered as a result of a decline in primary commodity prices. Such a system was instituted in 1963 by the International Monetary Fund (IMF). In 1969 the IMF also began making…

  • export foreland (geography)

    hinterland: An export foreland is the region to which the goods being shipped from the port are bound and an import foreland is the region from which goods being shipped to the port originate.

  • export hinterland (geography)

    hinterland: An export hinterland is the backcountry region from which the goods being shipped from the port originate and an import hinterland is the backcountry region for which the goods shipped to the port are destined. Export and import hinterlands have complementary forelands that lie on the…

  • export tax

    tariff: Export duties: Export duties are no longer used to a great extent, except to tax certain mineral, petroleum, and agricultural products. Several resource-rich countries depend upon export duties for much of their revenue. Export duties were common in the past, however, and were significant elements…

  • Export-Import Bank of China (bank, China)

    Djibouti: Transportation and telecommunications: Financed largely by the Export-Import Bank of China, the $3.4 billion project was completed in October 2016. Capable of accommodating freight trains at speeds of up to 75 miles (120 km) per hour and passenger trains at speeds of up to 100 miles (160 km) per hour, the electrified…

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