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designer drug

(Encyclopedia)designer drug, chemical substance synthesized in a laboratory that is intended to have effects similar to those of a drug that is a controlled substance, such as methamphetamine, marijuana, LSD, or an...

school vouchers

(Encyclopedia)school vouchers, government grants aimed at improving education for the children of low-income families by providing school tuition that can be used at public or private schools. The idea behind schoo...

chorionic villus sampling

(Encyclopedia)chorionic villus sampling (CVS) or chorionic villus biopsy (CVB) kōrˌē-ŏnˈĭk, kôrˌ– [key], diagnostic procedure in which a sample of chorionic villi from the developing placenta is removed f...

programmed instruction

(Encyclopedia)programmed instruction, method of presenting new subject matter to students in a graded sequence of controlled steps. Students work through the programmed material by themselves at their own speed and...

Hubble Space Telescope

(Encyclopedia)Hubble Space Telescope (HST), the first large optical orbiting observatory. Built from 1978 to 1990 at a cost of $1.5 billion, the HST (named for astronomer E. P. Hubble) was expected to provide the c...

induction, in logic

(Encyclopedia)induction, in logic, a form of argument in which the premises give grounds for the conclusion but do not necessitate it. Induction is contrasted with deduction, in which true premises do necessitate t...

Agent Orange

(Encyclopedia)Agent Orange, herbicide used by U.S. forces during the Vietnam War to expose enemy guerrilla forces in forested areas. Agent Orange contains varying amounts of dioxin. Exposure to the defoliant has be...

Rotblat, Sir Joseph

(Encyclopedia)Rotblat, Sir Joseph, 1908–2005, British physicist and anti-nuclear weapons activist, b. Warsaw, Poland; grad. Free Univ. of Poland (M.A., 1932), Univ. of Warsaw (Ph.D., 1938), Univ. of Liverpool (Ph...

Grateful Dead, The

(Encyclopedia)Grateful Dead, The, American rock music group formed in 1965 by guitarists Jerry Garcia, 1942–95, and Bob Weir, 1947–, harmonica player Ron “Pigpen” McKernan, 1945–73, bassist Phil Lesh, 194...