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toxoplasmosis

(Encyclopedia)toxoplasmosis, infection caused by Toxoplasma gondii, a single-celled parasitic microorganism that can infect most warm-blooded animals but reproduces only in animals of the cat family, who shed the p...

Poisson, Siméon Denis

(Encyclopedia)Poisson, Siméon Denis sēmāôNˈ dənēˈ pwäsôNˈ [key], 1781–1840, French mathematician and physicist. From 1802 he taught at the École polytechnique, Paris, and was also on the faculty of sc...

emphysema

(Encyclopedia)emphysema ĕmfĭsēˈmə [key], pathological or physiological enlargement or overdistention of the air sacs of the lungs. A major cause of pulmonary insufficiency in chronic cigarette smokers, emphyse...

stroboscope

(Encyclopedia)stroboscope strŏbˈəskōp [key], optical instrument for making a moving object appear to be slowed down or stationary. This effect is created by interrupting the observer's view so that the object i...

Heliopolis, ancient city, Egypt

(Encyclopedia)Heliopolis hēlēŏpˈəlĭs [key] [Gr.,=city of the sun], ancient city, N Egypt, in the Nile delta, 6 mi (10 km) below modern Cairo. It was noted as the center of sun worship, and its god Ra or Re wa...

blue shift

(Encyclopedia)blue shift or blueshift, in astronomy, the systematic displacement of individual lines in the spectrum of a celestial object toward the blue, or shorter wavelength, end of the visible spectrum. The am...

Bode, Johann Elert

(Encyclopedia)Bode, Johann Elert yōˈhän āˈlĕrt bōˈdə [key], 1747–1826, German astronomer. From 1772 to 1825 he was astronomer of the Academy of Science, Berlin, and from 1786, director of the Berlin Obse...

gas, fuel

(Encyclopedia)gas, fuel, gaseous substance that burns in air and releases enough heat to be useful as a fuel, while also remaining sufficiently stable at ordinary temperatures to permit long-term storage without de...

Sylvester II

(Encyclopedia)Sylvester II, c.945–1003, pope (999–1003), a Frenchman (b. Auvergne) named Gerbert; successor of Gregory V. In his youth he studied at Muslim schools in Spain and became learned in mathematics and...

Maclaurin, Colin

(Encyclopedia)Maclaurin, Colin məklôrˈĭn, –lärˈĭn [key], 1698–1746, Scottish mathematician and natural philosopher, one of the greatest mathematicians of his time. He was professor at Aberdeen and from 1...
 

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