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perturbation

(Encyclopedia)perturbation pŭrˌtərbāˈshən [key], in astronomy and physics, small force or other influence that modifies the otherwise simple motion of some object. The term is also used for the effect produce...

insider trading

(Encyclopedia)insider trading, stock market transactions made with knowledge of nonpublic information about corporate activity. In the United States, it has been illegal since 1934. The Securities and Exchange Comm...

Carroll, James

(Encyclopedia)Carroll, James, 1854–1907, American bacteriologist and army surgeon, b. Woolwich, England, M.D. Univ. of Maryland, 1891. He went to Canada at 15 and later joined the U.S. army. A member of the Yello...

Rankine temperature scale

(Encyclopedia)Rankine temperature scale, temperature scale having an absolute zero, below which temperatures do not exist, and using a degree of the same size as that used by the Fahrenheit temperature scale. Absol...

X ray

(Encyclopedia)CE5 Typical X-ray composite spectrum (intensity as a function of frequency) X ray, invisible, highly penetrating electromagnetic radiation of much shorter wavelength (higher frequency) than visibl...

complementarity principle

(Encyclopedia)complementarity principle, physical principle enunciated by Niels Bohr in 1928 stating that certain physical concepts are complementary. If two concepts are complementary, an experiment that clearly i...

gram-molecular weight

(Encyclopedia)gram-molecular weight, amount of a molecular substance whose weight, in grams, is numerically equal to the molecular weight of that substance. For example, one gram-molecular weight of molecular oxyge...

Kusch, Polykarp

(Encyclopedia)Kusch, Polykarp, 1911–93, American physicist, b. Blankenburg, Germany, Ph.D. Univ. of Illinois, 1936. Kusch was a researcher, professor, and administrator at Columbia from 1937 to 1972 and a profess...

Parisi, Giorgio

(Encyclopedia)Parisi, Giorgio, 1948–, Italian physicist, Ph.D. Sapienza University of Rome, 1970. Parisi is Professor of Theoretical Physics at Sapienza University....

Born, Max

(Encyclopedia)Born, Max, 1882–1970, British physicist, b. Germany, Ph.D. Univ. of Göttingen, 1907. He was head of the physics department at the Univ. of Göttingen from 1921 to 1933. When Nazi policies forced hi...