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allotropy

(Encyclopedia)allotropy əlŏˈtrəpē [key] [Gr.,=other form]. A chemical element is said to exhibit allotropy when it occurs in two or more forms in the same physical state; the forms are called allotropes. Allot...

Levitt, Michael

(Encyclopedia)Levitt, Michael, 1947–, British-Israeli-American biophysicist, b. South Africa, Ph.D. Cambridge, 1971. Levitt was a faculty member at Cambridge from 1974 to 1979 and at the Weizmann Institute in Isr...

Karplus, Martin

(Encyclopedia)Karplus, Martin, 1930–, Austrian-American theoretical chemist, b. Vienna, Ph.D. California Institute of Technology, 1953. He has been a professor at Harvard since 1967, studying the electronic struc...

Warshel, Arieh

(Encyclopedia)Warshel, Arieh, 1940–, Israeli-American chemist, b. Kibbutz Sde Nahum (in what is now Israel), Ph.D. Weizmann Institute, 1969. He has been a professor at the Univ. of Southern California since 1976....

e, in mathematics

(Encyclopedia)e, in mathematics, irrational number occurring widely in mathematics and science, approximately equal to the value 2.71828; it is the base of natural, or Naperian, logarithms. The number e is defined ...

Upanishads

(Encyclopedia)Upanishads o͞opănˈĭshădz [key], speculative and mystical scriptures of Hinduism, regarded as the wellspring of Hindu religious and speculative thought. The Upanishads, which form the last section...

pi

(Encyclopedia)pi, in mathematics, the ratio of the circumference of a circle to its diameter. The symbol for pi is π. The ratio is the same for all circles and is approximately 3.1416. It is of great importance in...

Richter scale

(Encyclopedia)Richter scale rĭkˈtər [key], measure of the magnitude of seismic waves from an earthquake. Devised in 1935 by the American seismologist Charles F. Richter (1900–1985) and technically known as the...

Höchst

(Encyclopedia)Höchst hökhst [key], industrial district of Frankfurt, in Hesse, central Germany. It is a leading center of the German chemical industry and was formerly the site of the I. G. Farben chemical and dy...

insecticides

(Encyclopedia)insecticides, chemical, biological, or other agents used to destroy insect pests; the term commonly refers to chemical agents only. The liabilities of chemical insecticides have encouraged interest ...