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  • EPR thought experiment (physics)

    Albert Einstein: Increasing professional isolation and death: …quantum theory led to the EPR (Einstein-Podolsky-Rosen) thought experiment. According to quantum theory, under certain circumstances two electrons separated by huge distances would have their properties linked, as if by an umbilical cord. Under these circumstances, if the properties of the first electron were measured, the state of the second…

  • EPRDF (political party, Ethiopia)

    Abiy Ahmed: Entry into politics: …which was part of the Ethiopian People’s Revolutionary Democratic Front (EPRDF) ruling coalition. In the following years he would go on to earn a master’s degree in transformational leadership (2011) from the International Leadership Institute in Addis Ababa, in partnership with Greenwich University in London; a master’s in business administration…

  • EPROM (computer memory)

    EPROM, Form of computer memory that does not lose its content when the power supply is cut off and that can be erased and reused. EPROMs are generally employed for programs designed for repeated use (such as the BIOS) but that can be upgraded with a later version of the

  • EPRP (political organization, Ethiopia)

    Ethiopia: Socialist Ethiopia (1974–91): One of them, the Ethiopian People’s Revolutionary Party (EPRP), believed so strongly in civilian rule that it undertook urban guerrilla war against the military rulers, and anarchy ensued in the following years.

  • EPS (biochemistry)

    mental disorder: Antipsychotic agents: These symptoms, which are called extrapyramidal symptoms (EPS), resemble those of Parkinson disease and include tremor of the limbs, bradykinesia (slowness of movement with loss of facial expression, absence of arm-swinging during walking, and a general muscular rigidity), dystonia (sudden sustained contraction of muscle groups, causing abnormal postures),

  • Epsilon Aurigae (star system)

    Epsilon Aurigae, binary star system of about third magnitude having one of the longest orbital periods (27 years) among eclipsing binaries (see eclipsing variable star). It is located an estimated 2,000 light-years from Earth in the constellation Auriga. The primary star is a yellow-white star

  • Epsilon Eridani (star)

    star: Hertzsprung-Russell diagram: …orange K-type stars such as Epsilon Eridani and finally to M-type red dwarfs thousands of times fainter than the Sun. The sequence is continuous; the luminosities fall off smoothly with decreasing surface temperature; the masses and radii decrease but at a much slower rate; and the stellar densities gradually increase.

  • Epsilon Orionis (star)

    star: Classification of spectral types: …hot B-type stars, such as Epsilon Orionis, are characterized by lines of helium and of singly ionized oxygen, nitrogen, and neon. In very hot O-type stars, lines of ionized helium appear. Other prominent features include lines of doubly ionized nitrogen, oxygen, and carbon and of triply ionized silicon, all of…

  • Epsilon Sagittarii (star)

    Sagittarius: The brightest star is Kaus Australis (from the Arabic for “bow” and the Latin for “southern,” respectively; it is also called Epsilon Sagittarii), with a magnitude of 1.9. Many of the stars are arranged in the prominent asterism called the Teapot.

  • Epsom and Ewell (district, England, United Kingdom)

    Epsom and Ewell, borough (district), administrative and historic county of Surrey, England. It is located at the foot of the North Downs, on the southwestern periphery of Greater London. The borough comprises three main conurbations: Epsom, Ewell, and Stoneleigh. The town of Epsom is the

  • Epsom Derby (horse race)

    Derby, one of the five classic English horse races, along with the Saint Leger, the Oaks, the One Thousand Guineas, and the Two Thousand Guineas. With a field limited to three-year-old colts and fillies, the Derby is run on turf on the first Saturday in June over a 1 12-mile (about 2,400-metre)

  • Epsom Downs (racetrack, Surrey, England, United Kingdom)

    Derby: …12-mile (about 2,400-metre) course at Epsom Downs, Surrey, England.

  • Epsom salt (chemical compound)

    Epsom and Ewell: …mineral springs there (from which Epsom salts were named). Stoneleigh, which was developed from farm fields and woods in the 1930s, took its name from the Stone family, which had owned the land, and from a mansion that had been located on their property.

  • epsomite (mineral)

    Epsomite, a common sulfate mineral, hydrated magnesium sulfate (MgSO4·7H2O). Its deposits are formed by evaporation of mineral waters, as at Epsom, Surrey, Eng., where it was discovered in 1695. It also is found as crusts and efflorescences in coal or metal mines, in limestone caves, and in the

  • Epstein, Barbara Zimmerman (American editor and journalist)

    Barbara Zimmerman Epstein, American editor and journalist (born Aug. 30, 1928, Boston, Mass.—died June 16, 2006, New York, N.Y.), cofounded (1963) and coedited (with Robert Silvers) the New York Review of Books (NYRB), a biweekly that was launched when a publishing strike in New York interrupted t

  • Epstein, Brian (British businessman)

    the Beatles: In autumn 1961 Brian Epstein, a local Liverpool record store manager, saw the band and fell in love. Unshakably convinced of their commercial potential, Epstein became their manager and proceeded to bombard the major British music companies with letters and tape recordings of the band, finally winning a…

  • Epstein, Israel (Chinese author and journalist)

    Israel Epstein, Polish-born Chinese author and journalist (born April 20, 1915, Warsaw, Pol., Russian Empire—died May 26, 2005, Beijing, China), through prolific writings and his position as editor of the newsmagazine China Today, served as an ardent propagandist for Mao Zedong and Chinese c

  • Epstein, Jeffrey (American financier)

    Prince Andrew, duke of York: …controversy for his friendship with Jeffrey Epstein, an American financier who became a convicted sex offender in 2008 and was awaiting trial on sex trafficking charges when he committed suicide in August 2019. One woman claimed that in 2001, while underage, she was forced by Epstein to have sex with…

  • Epstein, Julius J. (American screenwriter)

    Julius J. Epstein, American screenwriter (born Aug. 22, 1909, New York, N.Y.—died Dec. 30, 2000, Los Angeles, Calif.), had a long career, most noted for the adaptation—in partnership with his twin brother, Philip, and others—of the unproduced play Everybody Comes to Rick’s that became the s

  • Epstein, Philip G. (American writer and producer)
  • Epstein, Sir Jacob (British sculptor)

    Sir Jacob Epstein, one of the leading portrait sculptors of the 20th century, whose work, though seldom innovative, was widely heralded for its perceptive depiction of the sitter’s character and its modeling technique. Epstein’s early ambition was to be a painter, and he spent his adolescence

  • Epstein, Theo (American baseball executive)

    Theo Epstein, In the early morning of November 3, Theo Epstein, the president of baseball operations for the Chicago Cubs, cemented his reputation as Major League Baseball’s curse breaker when his Cubs won the franchise’s first World Series title in 108 years. Remarkably, that was the second time

  • Epstein, Theo Nathaniel (American baseball executive)

    Theo Epstein, In the early morning of November 3, Theo Epstein, the president of baseball operations for the Chicago Cubs, cemented his reputation as Major League Baseball’s curse breaker when his Cubs won the franchise’s first World Series title in 108 years. Remarkably, that was the second time

  • Epstein–Barr virus (infectious agent)

    Epstein-Barr virus (EBV), virus of the Herpesviridae family that is the major cause of acute infectious mononucleosis, a common syndrome characterized by fever, sore throat, extreme fatigue, and swollen lymph glands. Epstein-Barr virus was first reported by British scientists M.A. Epstein, Y.M.

  • Eptatretidae (hagfish family)

    hagfish: …represented in every ocean, and Eptatretidae, represented everywhere but the North Atlantic.

  • Eptesicus (genus of mammals)

    Serotine, (genus Eptesicus), any of 23 species of vesper bats (family Vespertilionidae). Frequently, the name serotine is used for Old World members of the genus, and brown bat is used for New World

  • Eptesicus fuscus (mammal)

    brown bat: The big brown bat (E. fuscus) is a common North American species, and the serotine (E. serotinus) is a stoutly built Eurasian form.

  • Eptesicus serotinus (bat species)

    brown bat: …North American species, and the serotine (E. serotinus) is a stoutly built Eurasian form.

  • Eptesowe (ancient temples, Thebes, Greece)

    Karnak: …temples, called in ancient times Ipet-Isut, “Chosen of Places.” The ruins cover a considerable area and are still impressive, though nothing remains of the houses, palaces, and gardens that must have surrounded the temple precinct in ancient times. The most northerly temple is the Temple of Mont, the war god,…

  • EPU

    international payment and exchange: The Basel Group: …in their postwar reconstruction, a European Payments Union was established to facilitate multilateral trade and settlements in advance of the time when it might be possible to reestablish full multilateralism on a world scale. The war had left a jumble of trade restrictions that could not be quickly abolished. The…

  • epulones (Roman religious official)

    Roman religion: Priests: …of the other body, the epulones, supervised religious feasts. There were also fetiales, priestly officials who were concerned with various aspects of international relationships, such as treaties and declarations of war. Also six Vestal Virgins, chosen as young girls from the old patrician families, tended the shrine and fire of…

  • Epulu (river, Africa)

    Ituri Forest: Climate and drainage: …Nepoko in the north, the Epulu and Nduye in the centre, and the Ibina in the south. None of these rivers is navigable, even by pirogue, for more than a few miles. The streams are fed by rains that are highly variable from month to month and from year to…

  • Epworth (England, United Kingdom)

    Isle of Axholme: The chief settlement is Epworth, the birthplace of John and Charles Wesley, founders of Methodism, whose father was rector of the parish; the church survives, and the restored rectory is maintained as a museum.

  • epyllion (poetry)

    Epyllion, brief narrative poem in dactylic hexameter of ancient Greece, usually dealing with mythological and romantic themes. It is characterized by lively description, miniaturistic attitude, scholarly allusion, and an elevated tone similar to that of the elegy. Such poems were especially popular

  • Epytoma…in Almagestum Ptolomei (work by Regiomontanus)

    Regiomontanus: …household and completed Peuerbach’s half-finished Epitome (c. 1462; first printed in 1496 as Epytoma…in Almagestum Ptolomei). His demonstration of an alternative to Ptolemy’s models for the orbits of Mercury and Venus with respect to the Sun gave Nicolaus Copernicus (1473–1543) the geometric key to reorient planetary motions around the Sun.…

  • Equal (chemical compound)

    Aspartame, synthetic organic compound (a dipeptide) of phenylalanine and aspartic acid. It is 150–200 times as sweet as cane sugar and is used as a nonnutritive tabletop sweetener and in low-calorie prepared foods (brand names NutraSweet, Equal) but is not suitable for baking. Because of its

  • equal charge displacement hypothesis (physics)

    nuclear fission: Fission decay chains and charge distribution: …empirical observation is called the equal charge displacement (ECD) hypothesis, and it has been confirmed by several physical measurements. In the above example the ECD would predict the most probable charges at about rubidium-37 and cesium-55. A strong shell effect modifies the ECD expectations for fragments having 50 protons. The…

  • equal consideration of interests, principle of (philosophy)

    speciesism: …on what he calls the principle of equal consideration of interests (PEC). This is the claim that one should give equal weight in one’s moral decision making to the like interests of all those affected by one’s actions. According to Singer, the PEC expresses what most people now understand (or…

  • Equal Education Opportunity Act (United States [1974])
  • Equal Employment Opportunity Commission (United States government agency)

    Equal Employment Opportunity Commission (EEOC), government agency established on July 2, 1965, by Title VII of the Civil Rights Act of 1964 to “ensure equality of opportunity by vigorously enforcing federal legislation prohibiting discrimination in employment”—particularly discrimination on the

  • equal opportunity (political theory)

    Equal opportunity, in political theory, the idea that people ought to be able to compete on equal terms, or on a “level playing field,” for advantaged offices and positions. Proponents of equal opportunity believe that the principle is compatible with, and indeed may justify, inequalities of

  • Equal Pay Act (United States [1963])

    Equal Pay Act of 1963 (EPA), landmark U.S. legislation mandating equal pay for equal work, in a measure to end gender-based disparity. The National War Labor Board first advocated equal pay for equal work in 1942, and an equal pay act was proposed in 1945. Eighteen years later, on June 10, 1963,

  • equal protection (United States law)

    Equal protection, in United States law, the constitutional guarantee that no person or group will be denied the protection under the law that is enjoyed by similar persons or groups. In other words, persons similarly situated must be similarly treated. Equal protection is extended when the rules of

  • equal rights (human rights)

    Equality, Generally, an ideal of uniformity in treatment or status by those in a position to affect either. Acknowledgment of the right to equality often must be coerced from the advantaged by the disadvantaged. Equality of opportunity was the founding creed of U.S. society, but equality among all

  • Equal Rights Amendment (proposed United States legislation)

    Equal Rights Amendment (ERA), a proposed but unratified amendment to the U.S. Constitution that was designed mainly to invalidate many state and federal laws that discriminate against women; its central underlying principle was that sex should not determine the legal rights of men or women. The

  • Equal Rights Party (political party, United States)

    Victoria Woodhull: …for the presidency by the Equal Rights Party.

  • equal tax division (Japanese tax)

    Japan: Muromachi government structure: This was called the equal tax division, or hanzei. Many shugo succeeded to their domains by inheritance, and in cases such as that of the Yamana family a single shugo sometimes held a number of provinces. If the primary agent of the Kamakura bakufu had been the jitō, the…

  • equal temperament (music)

    Equal temperament, in music, a tuning system in which the octave is divided into 12 semitones of equal size. Because it enables keyboard instruments to play in all keys with minimal flaws in intonation, equal temperament replaced earlier tuning systems that were based on acoustically pure

  • equal-field system (Asian land system)

    Equal-field system, official institution of land distribution and tax collection in traditional China and Japan. The system originated in China in 485 ce by order of the emperor Xiaowendi of the Bei (Northern) Wei dynasty (386–534/535 ce). It provided for the assignment of agricultural lands to all

  • equal-loudness curve (measurement)

    sound: Dynamic range of the ear: …of equal-loudness curves, sometimes called Fletcher-Munson curves after the investigators, the Americans Harvey Fletcher and W.A. Munson, who first measured them. The curves show the varying absolute intensities of a pure tone that has the same loudness to the ear at various frequencies. The determination of each curve, labeled by…

  • equality (human rights)

    Equality, Generally, an ideal of uniformity in treatment or status by those in a position to affect either. Acknowledgment of the right to equality often must be coerced from the advantaged by the disadvantaged. Equality of opportunity was the founding creed of U.S. society, but equality among all

  • equality (mathematics)

    metalogic: Characterizations of the first-order logic: …F is a sentence containing equality, a sentence G can be adjoined to it that embodies the special properties of identity relevant to the sentence F. The conjunction of F and G can then be treated as a sentence not containing equality (i.e., “=” can be treated as an arbitrary…

  • equality before the law (political philosophy)

    rule of law: …notion is the idea of equality before the law, which holds that no “legal” person shall enjoy privileges that are not extended to all and that no person shall be immune from legal sanctions. In addition, the application and adjudication of legal rules by various governing officials are to be…

  • equality of opportunity (political theory)

    Equal opportunity, in political theory, the idea that people ought to be able to compete on equal terms, or on a “level playing field,” for advantaged offices and positions. Proponents of equal opportunity believe that the principle is compatible with, and indeed may justify, inequalities of

  • Equality State (state, United States)

    Wyoming, constituent state of the United States of America. Wyoming became the 44th state of the union on July 10, 1890. It ranks 10th among the 50 U.S. states in terms of total area. It shares boundaries with six other Great Plains and Mountain states: Montana to the north and northwest, South

  • Equality, Community of (Pennsylvania, United States)

    Harmony, borough (town), Butler county, western Pennsylvania, U.S., on Connoquenessing Creek, 25 miles (40 km) north of Pittsburgh. It is known as the first settlement in America of the Harmonist Society (Rappites) led by George Rapp, an immigrant from Württemberg, Germany, who held

  • equalization (electronics)

    sound recording: The phonograph disc: …reversed in a process called equalization, providing the listener with a linear and realistic sound.

  • equalization bias (electronics)

    sound recording: The audiotape: Known as equalization bias, this signal has the effect of linearizing an inherently nonlinear magnetic medium, largely eliminating distortion.

  • Equalizer 2, The (film by Fuqua [2018])

    Melissa Leo: …The Equalizer (2014) and its sequel (2018) as well as Oliver Stone’s Snowden (2016), a biopic about an American intelligence contractor who revealed secret information-gathering programs conducted by the National Security Agency (NSA).

  • Equalizer, The (film by Fuqua [2014])

    Melissa Leo: …films included the action thriller The Equalizer (2014) and its sequel (2018) as well as Oliver Stone’s Snowden (2016), a biopic about an American intelligence contractor who revealed secret information-gathering programs conducted by the National Security Agency (NSA).

  • Equals (film by Doremus [2015])

    Nicholas Hoult: …starred with Kristen Stewart in Equals, about a young couple who begin a furtive romance in a futuristic society in which the development of feelings signals deadly disease and banishment.

  • Equanil (drug)

    Meprobamate, drug used in the treatment of anxiety. A central nervous system depressant, meprobamate acts selectively upon the spinal cord and the higher centres in the brain. Physical dependence may be produced after utilization of high doses for prolonged periods. Possible side effects include

  • equant (astronomy)

    Ptolemaic system: …point that he called the equant. The centre of the deferent was located midway between the equant and the Earth, as can be seen in the figure.

  • equant point (astronomy)

    Ptolemaic system: …point that he called the equant. The centre of the deferent was located midway between the equant and the Earth, as can be seen in the figure.

  • equation (mathematics)

    Equation, Statement of equality between two expressions consisting of variables and/or numbers. In essence, equations are questions, and the development of mathematics has been driven by attempts to find answers to those questions in a systematic way. Equations vary in complexity from simple

  • equations, systems of (mathematics)

    elementary algebra: Solving systems of algebraic equations: An extension of the study of single equations involves multiple equations that are solved simultaneously—so-called systems of equations. For example, the intersection of two straight lines, ax + by = c and Ax + By = C, can be found algebraically…

  • equations, theory of (mathematics)

    East Asian mathematics: Square and cube roots: The theory of equations developed in China within that framework until the 13th century. The solution by radicals that Babylonian mathematicians had already explored has not been found in the Chinese texts that survive. However, the specific approach to equations that developed in China occurs from…

  • Equator (geography)

    Equator, great circle around the Earth that is everywhere equidistant from the geographic poles and lies in a plane perpendicular to the Earth’s axis. This geographic, or terrestrial, Equator divides the Earth into the Northern and Southern hemispheres and forms the imaginary reference line on the

  • equator, celestial (astronomy)

    Equator: celestial equator is the great circle in which the plane of the terrestrial Equator intersects the celestial sphere; it consequently is equidistant from the celestial poles. When the Sun lies in its plane, day and night are everywhere of equal length, a twice-per-year occurrence known…

  • equator, pluviometric (meteorology)

    Congo River: Climate: From the pluviometric equator (an imaginary east-west line indicating the region of heaviest rainfall), which is situated slightly to the north of the geographic equator, the amount of rainfall decreases regularly in proportion to latitude. The northernmost points of the basin, situated in the Central African Republic,…

  • Equatoria (historical region, Africa)

    Sudan: Ismā?īl Pasha and the growth of European influence: …establish Egyptian hegemony over the equatorial regions of central Africa and to curtail the slave trade on the upper Nile. Baker remained in equatorial Africa until 1873, where he established the Equatoria province as part of the Egyptian Sudan. He had extended Egyptian power and curbed the slave traders on…

  • equatorial air mass (meteorology)

    air mass: The continental Tropical (cT) air mass originates in arid or desert regions in the middle or lower latitudes, principally during the summer season. It is strongly heated in general, but its moisture content is so low that the intense dry convection normally fails to reach the condensation level.…

  • equatorial bulge (geophysics)

    mechanics: Spinning tops and gyroscopes: The Earth bulges slightly at the Equator. As indicated in Figure 25, the effect of the Sun’s gravity on the near bulge (larger than it is on the far bulge) results in a net torque about the centre of the Earth. When the Earth is on the…

  • equatorial calms (meteorology)

    Doldrums, equatorial regions of light ocean currents and winds within the intertropical convergence zone (ITCZ), a belt of converging winds and rising air encircling Earth near the Equator. The northeast and southeast trade winds meet there; this meeting causes air uplift and often produces

  • equatorial convergence zone (meteorology)

    Intertropical convergence zone (ITCZ), belt of converging trade winds and rising air that encircles the Earth near the Equator. The rising air produces high cloudiness, frequent thunderstorms, and heavy rainfall; the doldrums, oceanic regions of calm surface air, occur within the zone. The ITCZ

  • equatorial coordinate

    star: Basic measurements: …in the equatorial system (the coordinates of which are called right ascension [α, or RA] and declination [δ, or DEC] and are given for some epoch—for example, 1950.0 or, currently, 2000.0). Positions of fainter stars are measured by using electronic imaging devices (e.g., a charge-coupled device, or CCD) with respect…

  • equatorial coordinate system (astronomy)

    star: Basic measurements: …measured very accurately in the equatorial system (the coordinates of which are called right ascension [α, or RA] and declination [δ, or DEC] and are given for some epoch—for example, 1950.0 or, currently, 2000.0). Positions of fainter stars are measured by using electronic imaging devices (e.g., a charge-coupled device, or…

  • equatorial countercurrent (ocean current)

    Equatorial countercurrent, current phenomenon noted near the equator, an eastward flow of oceanic water in opposition to and flanked by the westward equatorial currents of the Atlantic, Pacific, and Indian oceans. Lying primarily between latitude 3° and 10° N, the countercurrents shift south

  • equatorial current (oceanography)

    Equatorial current, ocean current flowing westward near the equator, predominantly controlled by the winds. Characteristically, equatorial-current systems consist of two westward-flowing currents approximately 600 miles (1,000 km) wide (North and South equatorial currents) separated by an

  • equatorial front (meteorology)

    Equatorial front, zone near the Equator in which the trade winds of the two hemispheres meet. The designation (about 1933) of this zone as a front was inspired by the close resemblance of its wind and weather patterns to those found along fronts in middle latitudes. Typically, the passage of a

  • Equatorial Guinea

    Equatorial Guinea, country located on the west coast of Africa. It consists of Río Muni (also known as Continental Equatorial Guinea), on the continent, and five islands (known collectively as insular Equatorial Guinea): Bioko (formerly Fernando Po), Corisco, Great Elobey (Elobey Grande), Little

  • Equatorial Guinea, flag of

    national flag consisting of horizontal stripes of green, white, and red, with a blue triangle at the hoist and the national coat of arms in the centre. The width-to-length ratio of the flag is approximately 2 to 3.The coat of arms of Equatorial Guinea contains the silk-cotton tree, also known as

  • Equatorial Guinea, history of

    Equatorial Guinea: History: The island of Bioko (formerly Fernando Po) was sighted by the Portuguese explorer Fern?o do Pó, probably in 1472. At first it was called Formosa (“Beautiful”). Annobón was probably sighted by Ruy de Sequeira on a New Year’s Day (hence the name, which means…

  • Equatorial Guinea, Republic of

    Equatorial Guinea, country located on the west coast of Africa. It consists of Río Muni (also known as Continental Equatorial Guinea), on the continent, and five islands (known collectively as insular Equatorial Guinea): Bioko (formerly Fernando Po), Corisco, Great Elobey (Elobey Grande), Little

  • equatorial mounting (astronomy)

    telescope: Light gathering and resolution: …in use at observatories have equatorial mountings. The mounting describes the orientation of the physical bearings and structure that permits a telescope to be pointed at a celestial object for viewing. In the equatorial mounting, the polar axis of the telescope is constructed parallel to Earth’s axis. The polar axis…

  • equatorial rain forest (ecology)

    Benin: Plant and animal life: The original rain forest, which covered most of the southern part of the country, has now largely been cleared, except near the rivers. In its place, many oil palms and r?nier palms have been planted and food crops are cultivated. North of Abomey the vegetation is an…

  • equatorial substituent (chemistry)

    hydrocarbon: Cycloalkanes: …bonds are referred to as equatorial (e) because they lie in a region corresponding to the approximate “equator” of the molecule. The shortest distances between nonbonded atoms are those involving axial hydrogens on the same side of the molecule.

  • equatorial system (astronomy)

    star: Basic measurements: …measured very accurately in the equatorial system (the coordinates of which are called right ascension [α, or RA] and declination [δ, or DEC] and are given for some epoch—for example, 1950.0 or, currently, 2000.0). Positions of fainter stars are measured by using electronic imaging devices (e.g., a charge-coupled device, or…

  • equatorial trough (meteorology)

    atmosphere: Convection, circulation, and deflection of air: …in an area called the equatorial trough). As the diverted air in the troposphere moves toward the poles, it tends to retain the angular momentum of the near-equatorial region, which is large as a result of Earth’s rotation. As a result, the poleward-moving air is deflected toward the right in…

  • Equatorial Undercurrent (oceanography)

    ocean current: Equatorial currents: This is called the Equatorial Undercurrent. It attains speeds of more than 1 metre per second at a depth of nearly 100 metres. It is driven by higher sea level in the western margins of the tropical ocean, producing a pressure gradient, which in the absence of a horizontal…

  • equatorial-trough disturbance (meteorology)

    Equatorial front, zone near the Equator in which the trade winds of the two hemispheres meet. The designation (about 1933) of this zone as a front was inspired by the close resemblance of its wind and weather patterns to those found along fronts in middle latitudes. Typically, the passage of a

  • eques (ancient Roman history)

    Eques, (Latin: “horseman”) in ancient Rome, a knight, originally a member of the cavalry and later of a political and administrative class as well as of the equestrian order. In early Rome the equites were drawn from the senatorial class and were called equites equo publico (“horsemen whose mounts

  • equestrian act (circus)

    circus: Equestrian acts: Continuing traditions from the days of Astley, scenic riding remained extremely popular in the 19th century, before the purely acrobatic style supplanted it. In scenic riding the equestrian, appropriately costumed, acted out a pantomime on horseback. The greatest exponent of this artistic mode…

  • equestrianism

    Horsemanship, the art of riding, handling, and training horses. Good horsemanship requires that a rider control the animal’s direction, gait, and speed with maximum effectiveness and minimum efforts. Horsemanship evolved, of necessity, as the art of riding with maximum discernment and a minimum of

  • equi-tonal system (music)

    African music: Equi-tonal systems: Two varieties are found: (1) equi-pentatonic (for example, in southern Uganda) and (2) equi-heptatonic (for example, in the lower Zambezi valley and in eastern Angola). These tone systems, with either five or seven notes per octave, differ radically from the two Western equal-interval…

  • equiangular spiral (mathematics)

    spiral: The equiangular, or logarithmic, spiral (see figure) was discovered by the French scientist René Descartes in 1638. In 1692 the Swiss mathematician Jakob Bernoulli named it spira mirabilis (“miracle spiral”) for its mathematical properties; it is carved on his tomb. The general equation of the logarithmic spiral is…

  • Equiano, Olaudah (abolitionist and writer)

    Olaudah Equiano, self-proclaimed West African sold into slavery and later freed. His autobiography, The Interesting Narrative of the Life of Olaudah Equiano; or, Gustavus Vassa, the African, Written by Himself (1789), with its strong abolitionist stance and detailed description of life in Nigeria,

  • Equidae (mammal)

    Equine, one of the mammal family of Equidae (order Perissodactyla) that includes the modern horses, zebras, and asses, as well as more than 60 species known only from fossils. All six modern members of the family are placed in the genus Equus. Only the races of E. caballus (including the myriad

  • equidecomposable figure (geometry)

    number game: Geometric dissections: …to a comprehensive theory of equidecomposable figures that was outlined in detail about 1960, two polygons are said to be equidecomposable if it is possible to dissect, or decompose, one of them into a finite number of pieces that can then be rearranged to form the second polygon. Obviously, the…

  • equigeopotential surface (geophysics)

    ocean current: Pressure gradients: …along a horizontal plane or geopotential surface, a surface perpendicular to the direction of the gravity acceleration. Horizontal gradients of pressure, though much smaller than vertical changes in pressure, give rise to ocean currents.

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