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neuron

(Encyclopedia)neuron, specialized cell in animals that, as a unit of the nervous system, carries information by receiving and transmitting electrical impulses. ...

Philomena of Dacia, Peter

(Encyclopedia)Philomena of Dacia, Peter, or Peter Nightingale, fl. 1291–1303, Danish astronomer and mathematician. He taught at the Univ. of Bologna (1291–92) and in Paris, and was a canon of Roskilde Cathedral...

Ulugh-Beg

(Encyclopedia)Ulugh-Beg or Ulug-Beg both: o͞oˈlo͞og bĕg [key], 1394–1449, Timurid ruler and astronomer. The grandson of Timur (or Tamerlane), he succeeded to the Timurid domain in 1447. A patron of the arts a...

Barnard, Edward Emerson

(Encyclopedia)Barnard, Edward Emerson, 1857–1923, American astronomer, b. Nashville, Tenn., grad. Vanderbilt Univ., 1887. From 1887 to 1895 he was astronomer at Lick Observatory in California, and from 1895 he wa...

almanac

(Encyclopedia)almanac, originally, a calendar with notations of astronomical and other data. Almanacs have been known in simple form almost since the invention of writing, for they served to record religious feasts...

decibel

(Encyclopedia)decibel dĕsˈəbĕlˌ, –bəl [key], abbr. dB, unit used to measure the loudness of sound. It is one tenth of a bel (named for A. G. Bell), but the larger unit is rarely used. The decibel is a measu...

gauss

(Encyclopedia)gauss gous [key] [for C. F. Gauss], abbr. G, unit of magnetic flux density (see flux, magnetic) equal to 0.0001 (10−4) weber per square meter. Since this unit is derived from the cgs system of units...

yard

(Encyclopedia)yard, abbr. yd, basic unit of length in the customary system of English units of measurement; all other units in the English system, such as the inch, foot, rod, and mile, are derived from it. Since 1...

ecliptic coordinate system

(Encyclopedia)ecliptic coordinate system, an astronomical coordinate system in which the principal coordinate axis is the ecliptic, the apparent path of the sun through the heavens. The ecliptic poles are the two p...

Oort, Jan Hendrik

(Encyclopedia)Oort, Jan Hendrik ōrt [key], 1900–1992, Dutch astronomer. He confirmed (1927) Bertil Lindblad's theory of the Milky Way galaxy's rotation. In the 1950s he and his colleagues used radio astronomical...