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capital punishment

(Encyclopedia)capital punishment, imposition of a penalty of death by the state. Since the 1970s almost all capital sentences in the United States have been imposed for homicide. There has been intense debate reg...

Ciliophora

(Encyclopedia)Ciliophora sĭlˌē-ŏfˈərə [key], phylum in the kingdom Protista consisting of the ciliates, or ciliophores, complex freshwater or saltwater protozoans that swim by the coordinated beating of thei...

HIV

(Encyclopedia)HIV, human immunodeficiency virus, either of two closely related retroviruses that invade T-helper lymphocytes and are responsible for AIDS. There are two types of HIV: HIV-1 and HIV-2. HIV-1 is respo...

herpesvirus

(Encyclopedia)herpesvirus, any of the family (Herpesviridae) of common DNA-containing viruses, many of which are associated with human disease. See cytomegalovirus; Epstein-Barr virus; herpes simplex; herpes zoster...

Gilbert, Walter

(Encyclopedia)Gilbert, Walter, 1932–, American molecular biologist, b. Boston, Ph.D. Cambridge, 1957. In 1968 he became a professor of biophysics at Harvard, where he had taught since 1959. He helped formulate a ...

histology

(Encyclopedia)histology hĭstŏlˈəjē [key], study of the groups of specialized cells called tissues that are found in most multicellular plants and animals. Histologists study the organization of tissues at all ...

Temin, Howard Martin

(Encyclopedia)Temin, Howard Martin, 1934–94, American virologist, b. Philadelphia, Ph.D. California Institute of Technology, 1959. A professor at the Univ. of Wisconsin in Madison, Temin began his cancer research...

paramecium

(Encyclopedia)paramecium parəmēˈsĭəm [key], unicellular organism of the genus Paramecium, of the ciliate phylum Ciliophora found in freshwater throughout the world. Like other protozoans, paramecia, previously...

thymine

(Encyclopedia)thymine thīˈmēn [key], organic base of the pyrimidine family. Thymine was the first pyrimidine to be purified from a natural source, having been isolated from calf thymus and beef spleen in 1893–...

Kornberg, Roger David

(Encyclopedia)Kornberg, Roger David, 1947–, American biochemist, b. St. Louis, Mo., Ph.D. Stanford, 1972; son of Arthur Kornberg. Kornberg held academic posts at Cambridge (1972–76) and Harvard (1976–78) befo...