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Lorentz contraction

(Encyclopedia)Lorentz contraction lôrˈĕnts [key], in physics, contraction or foreshortening of a moving body in the direction of its motion, proposed by H. A. Lorentz on theoretical grounds and based on an earli...

barbiturate

(Encyclopedia)barbiturate bärbĭchˈərātˌ [key], any one of a group of drugs that act as depressants on the central nervous system. High doses depress both nerve and muscle activity and inhibit oxygen consumpti...

uncertainty principle

(Encyclopedia)uncertainty principle, physical principle, enunciated by Werner Heisenberg in 1927, that places an absolute, theoretical limit on the combined accuracy of certain pairs of simultaneous, related measur...

Lind, James

(Encyclopedia)Lind, James, 1716–94, English naval surgeon. Considered the founder of naval hygiene in England, Lind observed on a ten-week cruise (1746) that 80 seamen of 350 came down with scurvy. In his Treatis...

mezzotint

(Encyclopedia)mezzotint mĕtˈsətĭnt, mĕdˈzə–, mĕzˈə– [key] [Ital.,=halftint], method of copper or steel engraving in tone. A Dutch officer, Ludwig von Siegen, is given credit for the invention of mezzo...

John Paul I

(Encyclopedia)John Paul I, 1912–78, pope (1978), an Italian (b. Canale d'Agordo) named Albino Luciani; successor of Paul VI. Born into a poor, working-class family, he trained at local seminaries and at the Grego...

Mott, Sir Nevill

(Encyclopedia)Mott, Sir Nevill, 1905–96, British physicist. A professor at the Univ. of Bristol (1933–54) and the Univ. of Cambridge (1954–71), Mott won the Nobel Prize in Physics in 1977 for a lifetime of re...

Haldane, John Scott

(Encyclopedia)Haldane, John Scott, 1860–1936, British scientist, b. Edinburgh; father of John Burdon Sanderson Haldane. He made many important contributions to mine safety, investigating principally the action of...

Goyen, Jan Josephszoon van

(Encyclopedia)Goyen, Jan Josephszoon van yän yōˈzəfsōn vän gōˈyən [key], 1596–1656, Dutch landscape painter. He studied at Leiden and Haarlem. In 1631 he settled at The Hague. His typically Dutch landsca...

ground bass

(Encyclopedia)ground bass, melodic phrase used repeatedly as a bass line. In its earlier form, developed in the 13th and 14th cent., the ground or basso ostinato [Ital.,=obstinate] never varied in harmonization or ...