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hypothalamus

(Encyclopedia)hypothalamus hīˌpəthălˈəməs [key], an important supervisory center in the brain, rich in ganglia, nerve fibers, and synaptic connections. It is composed of several sections called nuclei, each ...

sucker

(Encyclopedia)sucker, common name for members of the family Catostomidae, freshwater fish related to the minnows. Like minnows and the less closely related catfishes, the suckers possess an intricate set of bones f...

silicone

(Encyclopedia)silicone, polymer in which atoms of silicon and oxygen alternate in a chain; various organic radicals, such as the methyl group, CH3, are bound to the silicon atoms. Silicones, which are unusually sta...

sleep apnea

(Encyclopedia)sleep apnea, episodes of interrupted breathing during sleep. Obstructive sleep apnea is a common disorder in which relaxation of muscles in the throat repeatedly close off the airway during sleep; the...

smelt

(Encyclopedia)smelt, common name for a small, slender fish of the family Osmeridae. Most species are marine, but some ascend freshwater streams to spawn and others are landlocked in lakes. The rainbow or American s...

hydrogen

(Encyclopedia)hydrogen hīˈdrəjən [key] [Gr.,=water forming], gaseous chemical element; symbol H; at. no. 1; interval in which at. wt. ranges 1.00784–1.00811; m.p. −259.14℃; b.p. −252.87℃; density 0.08...

lutetium

(Encyclopedia)lutetium, formerly lutecium both: lo͞otēˈshēəm [key], metallic chemical element; symbol Lu; atomic number 71; at. wt. 174.9668; m.p. about 1,663℃; b.p. about 3,395℃; sp. gr. 9.835 at 25℃; v...

Nagasaki

(Encyclopedia)Nagasaki nägˌäsäˈkē [key], city (1990 pop. 444,599), capital of Nagasaki prefecture, W Kyushu, Japan, on Nagasaki Bay. It is one of Japan's leading ports. Shipbuilding is the chief industry; mac...

Townes, Charles Hard

(Encyclopedia)Townes, Charles Hard, 1915–2015, American physicist and educator, b. Greenville, S.C. He was educated at Furman Univ., Duke, and the California Institute of Technology (Ph.D., 1939), was on the tech...

horology

(Encyclopedia)horology hōrŏlˈəjē [key], science of measuring time and technology of constructing instruments for its measurement or recording. Early measurements of the passage of time were based on observatio...