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, 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 but that can be upgraded with a later version of a program. EPROMs are erased with ultraviolet

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.

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, 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

Adhara, the 22nd brightest star in the sky and one of the 57 stars of celestial navigation. The Bayer designation of Adhara is Epsilon Canis Majoris. (Epsilon is the fifth letter of the Greek alphabet, but Adhara is actually the second brightest star in the constellation, after Sirius. German

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.

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…

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, 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, one of the five classic English horse races, along with the Saint Leger, the Oaks, the 1,000 Guineas, and the 2,000 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 1 2 -mile (about 2,400-metre) course at

Epsom Derby, one of the five classic English horse races, along with the Saint Leger, the Oaks, the 1,000 Guineas, and the 2,000 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 1 2 -mile (about 2,400-metre) course at

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

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, 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

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…

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…

Jeffrey Epstein was an American serial sex trafficker, pedophile, and financier. Through his successful financial career, Epstein became a multimillionaire and developed a social circle that included extremely wealthy individuals, prominent politicians, and even royalty. He was eventually accused

Sir Jacob Epstein was 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-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 (EBV) was first reported by British scientists M.A. Epstein,

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

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

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.

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

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,…

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…

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…

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…

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, 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

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.…

emotional intelligence, set of psychological faculties that enable individuals to perceive, understand, express, and control their emotions and to discern and respond appropriately to the emotions of others. Emotional intelligence facilitates thoughts and actions that take emotions into

quality of life: Applications: …of these measures is the EuroQol 5D (EQ-5D), which addresses five dimensions of health: mobility, self-care, usual activities, pain/discomfort, and anxiety/depression. The five dimensions are divided into sublevels of patient-perceived problems (e.g., “no problems,” “severe problems”), from which a health state (or health profile) can be generated. The values attached…

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

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…

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 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, 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 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, 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

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

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

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, 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, 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

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, 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

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…

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…

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

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

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

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

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

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).

Queen Latifah: …hoping to become superstars, and The Equalizer (2021– ), in which she starred as a former CIA agent who becomes a vigilante. She also was cast in the special The Little Mermaid Live! (2019), and she played Hattie McDaniel in the miniseries Hollywood (2020). During this time Queen Latifah continued…

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).

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.

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

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

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

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

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…

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

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 (about…

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,…

Sudan: Ismāʿīl 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…

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.…

mechanics: Spinning tops and gyroscopes: 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 Earth. When Earth is on the other side…

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

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

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…

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, 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 during

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, 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, 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

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

history of Equatorial Guinea, a survey of notable events and people in the history of Equatorial Guinea, from the 15th century ce to the present day. Equatorial Guinea is located on the Atlantic coast of western Africa. The country comprises Río Muni (also known as Continental 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

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…

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 rônier palms have been planted and food crops are cultivated. North of Abomey the vegetation is an…

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.

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…

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…

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 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, 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 were provided for by

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…

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

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…

spiral: The logarithmic, or equiangular, spiral 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…

Olaudah Equiano was an abolitionist and writer whose autobiography, The Interesting Narrative of the Life of Olaudah Equiano; or, Gustavus Vassa, the African, Written by Himself (1789), became the first internationally popular slave narrative. In it, Equiano expresses a strong abolitionist stance

horse: Evolution of the horse: …history of the horse family, Equidae, began during the Eocene Epoch, which lasted from about 56 million to 33.9 million years ago. During the early Eocene there appeared the first ancestral horse, a hoofed, browsing mammal designated correctly as Hyracotherium but more commonly called Eohippus, the “dawn horse.” Fossils of…

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…

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.

igneous rock: Fabric: Even-grained, or equigranular, rocks are characterized by essential minerals that all exhibit the same order of grain size, but this implied equality need not be taken too literally. For such rocks the combination terms panidiomorphic-granular, hypidiomorphic-granular, and allotriomorphic-granular are applied according to the occurrence of…

bridge: Stone arch bridges: ogival arch by concealing the angle at the crown and by starting the curves of the arches vertically in their springings from the piers. This elliptical shape of arch, in which the rise-to-span ratio was as low as 1:7, became known as basket-handled and has…