error In applied mathematics, the difference between a value and an estimate of that value. In statistics, a common example is the difference between the mean age of a given group of people (see mean, median, and mode) and that of a sample drawn from the group. In numerical analysis, an example of round-off error is the difference between the true value of Pl and commonly substituted expressions like 22 /i and shorter versions like 3.14159. Truncation error results from using only the first few terms of an infinite series. Relative error is the ratio of the size of an error to the size of the quantity measured, and percentage error is relative error expressed as a percent.
Erskine Vor-skonV (of Restormel), Thomas Erskine, 1 st Baron
(b. Jan. 10, 1750, Edinburgh, Scot.— -d. Nov. 17, 1823, Almondell, Lin¬ lithgowshire) Scottish lawyer. He was the youngest son of Henry David Erskine, 10th Earl of Buchan. After service in the British navy and army, he entered the law, and in 1778 he was called to the bar. His practice flourished after he won a seminal libel case, and he went on to make important contributions to the protection of personal liberties. His defense of politicians and reformers on charges of treason and related offenses, including an unsuccessful defense of Thomas Paine (1792), checked repres¬ sive measures taken by the British government in the aftermath of the French Revolution. He contributed to the law of criminal responsibility by defending, on the novel ground of insanity, a would-be assassin of George III. He served in Parliament (1783-84, 1790-1806) until elevated to the peerage (1806), and he was lord chancellor (1806-07) in William Grenville’s “ministry of all talents.” In 1820 he defended Queen Caro¬ line, whom George IV had brought to trial before the House of Lords for adultery in order to deprive her of her rights and title. Erskine’s court¬ room speeches are characterized by vigour, cogency, and lucidity and often by great literary merit.
Erte Ver-'ta\ orig. Romain de Tirtoff (b. Nov. 23,1892, St. Petersburg, Russia—d. April 21, 1990, Paris,
France) Russian-born French fashion illustrator and designer. In 1912 he arrived in Paris, where he worked briefly with the couturier Paul Poiret.
From 1916 to 1937 he published elegant, highly stylized illustrations depicting models in mannered poses against Art Deco interiors in Harp¬ er's Bazaar. He also designed theat¬ rical scenery and costumes for the Folies-Bergere in Paris (1919-30), and in the 1920s he costumed per¬ formers in U.S. musicals, most nota¬ bly the Ziegfeld Follies. His designs continue to be widely reproduced.
Ervin, Sam orig. Samuel James Ervin, Jr. (b. Sept. 27,
1896, Morganton, N.C., U.S.—d.
April 23, 1985, Winston-Salem,
N.C.) U.S. senator (1954-74). He served on the Supreme Court of North Carolina (1948-54) before being appointed to a vacant U.S.
Senate seat. An eloquent expert on the Constitution, he sat on the Sen¬ ate committee that censured Sen.
Joseph McCarthy, and he helped investigate labour racketeering. In the 1960s he led Southern filibusters
Afternoon dress of black and white satin designed by Erte for Harper's Bazaar 1924
against civil-rights legislation while simultaneously acting as a champion of civil liberties. As chairman of the special committee investigating the
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Erving ► Escher I 633
Watergate scandal, he became something of a folk hero for his unceas¬ ing pursuit of evidence in the face of White House claims of executive privilege. His earthy humour, distinctive accent, and unfailing charm con¬ tributed to his popularity.
Erving, Julius (Winfield) (b. Feb. 22, 1950, Roosevelt, N.Y., U.S.) U.S. basketball star. He played two years at the University of Massachu¬ setts before joining the professional American Basketball Association (ABA). At 6 ft 7 in. (2 m), “Doctor J” played forward for the Virginia Squires (1971-73) and the New York Nets (1973-76), whom he led to two ABA titles (1974, 1976). After the merger of the ABA and NBA, Erv¬ ing was traded to the Philadelphia 76ers (1977-87) and won a league title in 1983. He was known for swarming defense, imaginative drives to the basket, and climactic slam dunks.
erythema \,er-3- , the-m3\ Abnormal skin redness from increased blood flow, caused by dilation and irritation of surface capillaries. It has a variety of manifestations. In erythema multiforme, a symptom complex seen in several diseases, spots appear suddenly, often with a bull’s-eye pattern. It may become life-threatening in severe cases; in mild cases symptoms may recur. Hormone treatment may be effective. In erythema nodosum, a hypersensitivity reaction usually associated with strep infection (see strep¬ tococcus), drugs, or the disease sarcoidosis, painful red nodules appear in the deeper skin layer of the lower legs. They usually disappear over sev¬ eral weeks and do not recur. Another form of erythema is pellagra.
Erythrae \'er-9-,thre\ Ancient city of Lydia. Located on the Aegean coast opposite the island of Chios, it was one of the 12 Ionian Cities. The origi¬ nal site of the settlement is uncertain, but from the 4th century bc it was located at modern Ildir, where traces of the wall circuit, theatre, and cita¬ del are visible. It took various sides in 5th century bc Greek politics, came under Persian control, and was freed by Alexander the Great in 334 bc. A free city in the Roman province of Asia, it was noted for its wine and goats, as well as its prophetic Sibyls, Herophile and Athenais.
erythroblastosis fetalis Vi-.rith-ro-.blas-'to-sos-fi-'ta-losV or hemo¬ lytic disease of the newborn Anemia in an infant, caused when a pregnant woman produces antibodies to an antigen in her fetus’s red blood cells. An Rh-negative woman (see Rh blood-group system) with an Rh-positive fetus whose ABO blood group (see ABO blood-group system) matches hers is likely to have an immune reaction after the first such pregnancy, which sensitizes her when fetal red blood cells enter her blood¬ stream, usually during labour. If blood typing shows incompatibility, an anti-Rh antibody injection given to the mother after the birth can destroy the fetal red cells, thus preventing trouble in a future pregnancy. If amnio¬ centesis detects products of blood destruction, Rh-negative blood transfu¬ sions to the fetus before birth or exchange transfusion after it may save the baby’s life. ABO incompatibilities are more common but usually less severe.
erythrocyte \i-'rith-r9- 1 slt\ or red blood cell or red blood cor¬ puscle Blood cell that carries oxygen from the lungs to the body tissues. Hemoglobin gives the cell—and whole blood—its colour. Red cells are small, round, flexible, and concave on both sides and lack a nucleus. They develop continuously in bone marrow in several stages and are stored in the spleen. The mature form lives 100-120 days. Adult human blood has about 5.2 million red cells per cu mm. Some conditions change their shape (e.g., pernicious anemia, sickle-cell anemia) or number (e.g., anemia, poly¬ cythemia).
Erzberger \ , erts- 1 ber-gor\ / Matthias (b. Sept. 20,1875, Buttenhausen, Wtirttemberg, Ger.—d. Aug. 26, 1921, Black Forest, Baden) German poli¬ tician. Elected to the Reichstag in 1903, he became the leader of the left wing of the Centre Party. During World War I he was involved in the Reichstag resolution proposing a negotiated peace with no territorial gains. He headed the German delegation that signed the Armistice, and he advocated acceptance of the Treaty of Versailles. In 1919-20 he served as vice-chancellor and finance minister. As a supporter of the republican- democratic system, he became the victim of a slander campaign from the extreme right. He resigned his ministry and was later assassinated by nationalist partisans.