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tritium

(Encyclopedia)tritium trĭtˈēəm [key], radioactive isotope of hydrogen with mass number 3. The tritium nucleus, called a triton, contains one proton and two neutrons. It has a half-life of 12.5 years and decays ...

blood substitute

(Encyclopedia)blood substitute, substance that mimics the function of blood. Blood substitutes typically concentrate only on reproducing the function of hemoglobin, the molecule that carries oxygen through the body...

bluebird

(Encyclopedia)bluebird, common name for a North American migratory bird of the family Turdidae (thrush family). The eastern bluebird, Sialia sialis, is among the first spring arrivals in the North. It is about 7 in...

biennial

(Encyclopedia)biennial, plant requiring two years to complete its life cycle, as distinguished from an annual or a perennial. In the first year a biennial usually produces a rosette of leaves (e.g., the cabbage) an...

Raman effect

(Encyclopedia)Raman effect räˈmən [key], appearance of additional lines in the spectrum of monochromatic light that has been scattered by a transparent material medium. The effect was discovered by C. V. Raman i...

Schenck v. United States

(Encyclopedia)Schenck v. United States, case decided in 1919 by the U.S. Supreme Court. During World War I, Charles T. Schenck produced a pamphlet maintaining that the military draft was illegal, and was convicted ...

San Francisco Ballet

(Encyclopedia)San Francisco Ballet, America's first classical ballet company, est. 1933 as the San Francisco Opera Ballet by the dancer Adolph Bolm. Based at the War ...

Simon, Herbert Alexander

(Encyclopedia)Simon, Herbert Alexander, 1916–2001, American social scientist and economist, b. Milwaukee, grad. Univ. of Chicago (B.A., 1936, Ph.D., 1943). A professor of computer science and psychology at Carneg...

robbery

(Encyclopedia)robbery, in law, felonious taking of property from a person against his will by threatening or committing force or violence. The injury or threat may be directed against the person robbed, his propert...

free energy

(Encyclopedia)free energy or Gibbs free energy, quantity derived from the relationships between heat and work studied in thermodynamics and used as a measure of the relative stability of a physical or chemical syst...