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springtail

(Encyclopedia)springtail, common name for any of the minute, primitive six-legged arthropods of the order Collembola. The springtail is named for a springlike mechanism on the underside of the abdomen. When at rest...

electromagnetic radiation

(Encyclopedia)CE5 Electromagnetic spectrum electromagnetic radiation, energy radiated in the form of a wave as a result of the motion of electric charges. A moving charge gives rise to a magnetic field, and if ...

Weiss, Rainer

(Encyclopedia)Weiss, Rainer, 1932–, American physicist, b. Berlin, Germany, Ph.D. Massachusetts Institute of Technology, 1962. Weiss has been on the faculty of the Massachusetts Institute of Technology since 1964...

holography

(Encyclopedia)holography hŏlŏgˈrəfē, hō– [key], method of reproducing a three-dimensional image of an object by means of light wave patterns recorded on a photographic plate or film. Holography is sometimes...

Flamborough Head

(Encyclopedia)Flamborough Head flămˈbərə [key], chalk promontory, East Riding of Yorkshire, E England, N of Bridlington Bay. There is a lighthouse at the tip. Danes' Dyke (an ancient earthwork fortification) cr...

pulse, in anatomy

(Encyclopedia)pulse, alternate expansion and contraction of artery walls as heart action varies blood volume within the arteries. Artery walls are elastic. Hence they become distended by increased blood volume duri...

East River

(Encyclopedia)East River, tidal strait, 16 mi (26 km) long and 600–4,000 ft (183–1,219 m) wide, connecting Upper New York Bay and Long Island Sound, New York City, and separating the boroughs of Manhattan and t...

delta

(Encyclopedia)delta [from triangular shape of the Nile delta, like the Greek letter delta], a deposit of clay, silt, and sand formed at the mouth of a river where the stream loses velocity and drops part of its sed...

Moncton

(Encyclopedia)Moncton mŭngkˈtən [key], city (1991 pop. 57,010), SE N.B., Canada, on the Petitcodiac River. Although its rail repair yards were closed in 1988, it is an air and rail transportation center and a ro...

estuary

(Encyclopedia)estuary ĕsˈcho͝oĕrˌē [key], partially enclosed coastal body of water, having an open connection with the ocean, where freshwater from inland is mixed with saltwater from the sea. One type of est...