radiation restricted area
51Europe, history of — Introduction history of European peoples and cultures from prehistoric times to the present. Europe is a more ambiguous term than most geographic expressions. Its etymology is doubtful, as is the physical extent of the area it designates.… …
52Bohr model — In atomic physics, the Bohr model created by Niels Bohr depicts the atom as a small, positively charged nucleus surrounded by electrons that travel in circular orbits around the nucleus mdash;similar in structure to the solar system, but with… …
53Ecology — For other uses, see Ecology (disambiguation). Ecology …
54Magnetic resonance imaging — MRI redirects here. For other meanings of MRI or Mri, see MRI (disambiguation). Magnetic resonance imaging Intervention Sagittal MR image of the knee ICD 10 PCS B?3?ZZZ …
55spectroscopy — spectroscopist /spek tros keuh pist/, n. /spek tros keuh pee, spek treuh skoh pee/, n. the science that deals with the use of the spectroscope and with spectrum analysis. [1865 70; SPECTRO + SCOPY] * * * Branch of analysis devoted to identifying… …
56United States — a republic in the N Western Hemisphere comprising 48 conterminous states, the District of Columbia, and Alaska in North America, and Hawaii in the N Pacific. 267,954,767; conterminous United States, 3,022,387 sq. mi. (7,827,982 sq. km); with… …
57Silurian Period — Interval of geologic time, 443–417 million years ago. The third period of the Paleozoic Era, the Silurian follows the Ordovician Period and precedes the Devonian. It marks the first appearance of land plants and jawed fishes. The continents were… …
58Business and Industry Review — ▪ 1999 Introduction Overview Annual Average Rates of Growth of Manufacturing Output, 1980 97, Table Pattern of Output, 1994 97, Table Index Numbers of Production, Employment, and Productivity in Manufacturing Industries, Table (For Annual… …
59boreal forest — ▪ northern forest Introduction also called taiga vegetation composed primarily of cone bearing, needle leaved, or scale leaved evergreen trees, found in regions that have long winters and moderate to high annual precipitation. The… …
60Chernobyl disaster — This article is about the 1986 nuclear plant accident in Ukraine. For other uses, see Chernobyl (disambiguation). Chernobyl disaster …
