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Martin, Saint, c.316–397, bishop of Tours

(Encyclopedia)Martin, Saint, c.316–397, bishop of Tours. Born a heathen in Pannonia (in modern Hungary), the son of a soldier, he became a convert and refused to fight Christians. He went (c.360) to St. Hilary of...

life preserver

(Encyclopedia)life preserver, a personal flotation device (PFD) intended to keep the wearer afloat, particularly in case of shipwreck. A Type I PFD will keep even unconscious people afloat in a face–up position; ...

Kellogg, John Harvey

(Encyclopedia)Kellogg, John Harvey, 1852–1943, American physician, health-food advocate, and breakfast cereal developer, b. Tyrone, N.Y., grad. New York Univ. (M.D., 1875) and continued his medical studies in Eur...

Lehn, Jean-Marie

(Encyclopedia)Lehn, Jean-Marie zhäNˈ-märēˈ lĕN [key], 1939–, French chemist, Ph.D. Univ. of Strasbourg, 1963. A professor at Louis Pasteur Univ. (1970–78) and the Collège de France (1979–), Lehn did gr...

potentiometer

(Encyclopedia)potentiometer. 1 Manually adjustable, variable, electrical resistor. It has a resistance element that is attached to the circuit by three contacts, or terminals. The ends of the resistance element are...

phenylketonuria

(Encyclopedia)phenylketonuria fĕnˌəlkētˌəno͝orˈēə [key] (PKU), inherited metabolic disorder caused by a deficiency in a specific enzyme (phenylalanine hydroxylase). The absence of this enzyme, a recessive...

cataract

(Encyclopedia)cataract, in medicine, opacity of the lens of the eye, which impairs vision. In the young, cataracts are generally congenital or hereditary; later they are usually the result of degenerative changes b...

wind shear

(Encyclopedia)wind shear, a sudden, drastic change in wind direction or speed over a comparatively short distance. Most winds travel horizontally, as does most wind shear, but under certain conditions, including th...

Vazov, Ivan

(Encyclopedia)Vazov, Ivan ĭvänˈ väˈzôf [key], 1850–1921, Bulgarian poet, novelist, and playwright, the first professional man of letters in Bulgaria. His work was inspired by the political upheavals of the ...

waveguide

(Encyclopedia)waveguide, device that controls the propagation of an electromagnetic wave so that the wave is forced to follow a path defined by the physical structure of the guide. Waveguides, which are useful chie...