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Yar'Adua, Umaru Musa

(Encyclopedia)Yar'Adua, Umaru Musa o͞omäˈro͞o mo͞oˈsä yär ädo͞oˈä [key], 1951–2010, Nigerian politician, president of Nigeria (2007–10). Born into a family active in Nigerian political and military ...

tennessine

(Encyclopedia)tennessine tĕnˈəsēn [key], artificially produced radioactive chemical element; symbol Ts; at. no. 117; mass number of most stable isotope 294; m.p., b.p., sp. gr., and valence unknown. Tennessine ...

carboxyl group

(Encyclopedia)carboxyl group kärbŏkˈsĭl [key], in chemistry, functional group that consists of a carbon atom joined to an oxygen atom by a double bond and to a hydroxyl group, OH, by a single bond. Carboxylic a...

Carey, Peter

(Encyclopedia)Carey, Peter, 1943–, Australian novelist, b. near Melbourne. Carey's combination of science fiction and fantasy motifs with a realistic style, displayed in the short stories in The Fat Man in Histor...

livermorium

(Encyclopedia)livermorium, artificially produced radioactive chemical element; symbol Lv; at. no. 116; mass number of most stable isotope 292; m.p., b.p., sp. gr., and valence unknown. Situated in Group 16 of the p...

Merkel, Angela

(Encyclopedia)Merkel, Angela änˈgĕlä märˈkəl [key], 1954–, German politician, b. Hamburg as Angela Dorothea Kasner. The daughter of a Lutheran pastor, she grew up in what was then East Germany. She trained...

amino group

(Encyclopedia)amino group, in chemistry, functional group that consists of a nitrogen atom attached by single bonds to hydrogen atoms, alkyl groups, aryl groups, or a combination of these three. An organic compound...

equation

(Encyclopedia)equation, in mathematics, a statement, usually written in symbols, that states the equality of two quantities or algebraic expressions, e.g., x+3=5. The quantity x+3, to the left of the equals sign (=...

Comte, Auguste

(Encyclopedia)Comte, Auguste ōgüstˈ kôNt [key], 1798–1857, French philosopher, founder of the school of philosophy known as positivism, educated in Paris. From 1818 to 1824 he contributed to the publications ...

promethium

(Encyclopedia)promethium prōmēˈthēəm [key], artificially produced radioactive chemical element; symbol Pm; at. no. 61; mass no. of most stable isotope 145; m.p. 1,042℃; b.p. 3,000℃ (estimated); sp. gr. unk...