Me 109 See Messerschmitt 109 Me Nam River See Chao Phraya River
mead Alcoholic beverage fermented from honey and water. It can be light or rich, sweet or dry, or even sparkling. Alcoholic drinks made from honey were common in ancient Scandinavia, Gaul, Teutonic Europe, and Greece; they were particularly common in northern Europe, where grape¬ vines do not flourish. By the 14th century, ale and sweetened wine were surpassing mead in popularity. Today mead is made as a sweet or dry wine of low alcoholic strength. Spiced mead is called metheglin.
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Mead, George Herbert (b. Feb. 27, 1863, South Hadley, Mass., U.S.—d. April 26, 1931, Chicago, Ill.) U.S. philosopher, sociologist, and social psychologist prominent in the development of pragmatism. He stud¬ ied at Oberlin College, graduated from Harvard University (B.A., 1888), and went on to study philosophy and psychology at the Universities of Leipzig and Berlin (1888-91). Mead then taught philosophy and psychol¬ ogy at the University of Michigan (1891-94) with John Dewey and Charles Horton Cooley. In 1894 he joined Dewey in moving to the University of Chicago and taught there the rest of his life. Mead’s focus was the rela¬ tionship between the self and society, particularly the emergence of the human self in the process of social interaction. His works include The Philosophy of the Present (1932) and Mind, Self, and Society (1934). See also INTERACTIONS.
Mead, Lake Reservoir of the Hoover Dam, on the Arizona-Nevada bor¬ der in the U.S. One of the largest man-made lakes in the world, it was formed by the damming of the Colorado River. Lake Mead is 115 mi (185 km) long and 1-10 mi (1.6-16 km) wide; it has a capacity of over 31 million acre ft (38 billion cubic m), with a surface area of 229 sq mi (593 sq km). It was named after Elwood Mead, commissioner of reclamation. Lake Mead National Recreation Area (established 1936) has an area of 2,338 sq mi (6,055 sq km) and extends 240 mi (386 km) along the river.
Mead, Margaret (b. Dec. 16, 1901, Philadelphia, Pa., U.S.—d. Nov. 15, 1978, New York, N.Y.) U.S. anthropologist. She studied under Franz Boas and Ruth Benedict at Columbia University and did fieldwork in Samoa before completing her Ph.D. (1929). The first and most famous of her 23 books, Coming of Age in Samoa (1928), presents evidence in support of cultural determinism with respect to the formation of personality or tem¬ perament. Her other books include Sex and Temperament in Three Primi¬ tive Societies (1935), Male and Female (1949), and Culture and Commitment (1970). Her theories caused later 20th-century anthropolo¬ gists to question both the accuracy of her observations and the soundness of her conclusions. In her later years she became a prominent voice on such wide-ranging issues as women’s rights and nuclear proliferation, and her great fame owed as much to the force of her personality and her out¬ spokenness as to the quality of her scientific work. She served in cura¬ torial positions at the American Museum of Natural History for over 50 years.
Meade, George G(ordon) (b. Dec. 31, 1815, Cadiz, Spain—d. Nov. 6, 1872, Philadelphia, Pa., U.S.) U.S. general in the American Civil War. He was the son of a U.S. naval agent in Spain. After graduating from West Point in 1835, he worked as a surveyor. He reentered the army in 1842 and in 1861 was commissioned brigadier general in the Pennsylvania volun¬ teers. He fought at Bull Run, Antietam, and Chancellorsville. Three days before the Battle of Gettysburg, he replaced Joseph Hooker as commander of the Army of the Potomac. At Gettysburg he repulsed the Confederate attack but was criticized for failing to pursue Robert E. Lee’s forces. From 1864 he was subordinate to Gen. Ulysses S. Grant, whom he served loy¬ ally. After the war he commanded several military departments.
meadowlark Any sharp-billed, plump songbird of the genus Sturnella (family Icteridae), 8-11 in. (20-28 cm) long. The two North American species are streaked brown above and have a yellow breast crossed by a black V; the short tail has distinctive white outer feathers. The eastern, or common, meadowlark ( S. magna), from eastern Canada to Brazil, has a simple four-note whistle; the western meadowlark ( S. neglecta ), from western Canada to Mexico, has an intricate fluting song. Meadowlarks eat insects in summer and seeds in fall and winter. Their nests are grass domes hidden in fields.
mealybug Any insect of the family Pseudococcidae (order Homoptera). Not a true bug, the mealybug is covered by a white sticky powder resembling cornmeal. The females, about 0.4 in. (1 cm) long, and “crawlers” (the active young) cluster along the veins and undersides of leaves, especially of citrus trees and potted plants; the males are active two-winged fliers. Common species are the citrus mealybug ( Pseudococ¬ cus citri) and the citrophilus mealybug (P gahani).
mean life In radioactivity, the average lifetime of all the nuclei of a par¬ ticular unstable atomic species. This time interval is the sum of the life¬ times of all the individual unstable nuclei in a sample, divided by the total number of unstable nuclei present. It is the reciprocal of the decay con¬ stant. For a given isotope, the mean life is always 1.443 times its half- life. For example, lead-209 decays to bismuth-209 with a half-life of 3.25 hours and a mean life of 4.69 hours.
mean, median, and mode In mathematics, the three principal ways of designating the average value of a list of numbers. The arithmetic mean is found by adding the numbers and dividing the sum by the number of numbers in the list. This is what is most often meant by an average. The median is the middle value in a list ordered from smallest to largest. The mode is the most frequently occurring value on the list. There are other types of means. A geometric mean is found by multiplying all values in a list and then taking the root of that product equal to the number of val¬ ues (e.g., the square root if there are two numbers). The geometric mean is typically used in cases of exponential growth or decline (see exponen¬ tial function). In statistics, the mean of a random variable is its expected value—i. e., the theoretical long-run arithmetic mean of the outcomes of repeated trials, such as a large number of tosses of a die.
mean-value theorems In mathematics, two theorems, one associ¬ ated with differential calculus and one with integral calculus. The first pro¬ poses that any differentiable function defined on an interval has a mean value, at which a tangent line is parallel to the line connecting the end¬ points of the function’s graph on that interval. For example, if a car cov¬ ers a mile from a dead stop in one minute, it must have been traveling exactly a mile a minute at some point along that mile. In integral calcu¬ lus, the mean value of a function on an interval is, in essence, the arith¬ metic mean (see mean, median and mode) of its values over the interval. Because the number of values is infinite, a true arithmetic mean is not possible. The theorem shows how to find the mean value using a definite integral. See also Rolle's theorem.
meander \me-'an-d9r\ Extreme U-bend in a stream, usually occurring in a series, that is caused by flow characteristics of the water. Mean¬ ders form in stream-deposited sedi¬ ments and may stack up upstream of an obstruction, resulting in a goose¬ neck or extremely bowed meander. A cutoff may form through the goose¬ neck and allow the former meander bend to be sealed off as an oxbow lake. Silt deposits may eventually fill the lake to form a marsh or a mean¬ der scar.
meaning In philosophy and lin¬ guistics, the sense of a linguistic expression, sometimes understood in contrast to its referent. For example, the expressions “the morning star” and “the evening star” have different meanings, though their referent (Venus) is the same. Some expres¬ sions have meanings but no referents (“the present king of France”) or ref¬ erents but no meanings (“that”). The literal or conventional meaning of an expression may differ from what a speaker of that expression means by uttering it on a particular occasion; this is the case with similes, statements uttered ironically, and statements that convey various “conversational implicatures,” as in the following examples: “She entered the house and shot him” implicates that she shot him in the house after she entered it, though this is not part of the sen¬ tence’s literal meaning; “John has three sons” implicates that John has no more than three sons, though again the sentence does not literally say this. Other non-literal aspects of meaning include the potential for carrying out various “speech acts” (see speech act theory); e.g., uttered in the appropri¬ ate circumstances, the sentence “I christen thee the Joseph Stalin ,” con¬ stitutes the act of naming a ship, and the sentence “I am cold” constitutes a request to close the window. See also pragmatics; semantics.