Columbia Encyclopedia

(Encyclopedia) Sudbury, city (1991 pop. 92,884), central Ont., Canada. It is the center of Canada's largest mining region, which produces much of the world's nickel and large quantities of copper, platinum, gold, si...

(Encyclopedia) photosynthesis fōˌtōsĭnˈthəsĭs [key], process in which green plants, algae, and cyanobacteria utilize the energy of sunlight to manufacture carbohydrates from carbon dioxide and water in the pr...

(Encyclopedia) Caltagirone kälˌtäjērôˈnā [key], city, SE Sicily, Italy. An agricultural and sulfur-mining center, ...

(Encyclopedia) selenium səlēˈnēəm [key], nonmetallic chemical element; symbol Se; at. no. 34; at. wt. 78.96; m.p. 217℃; b.p. about 685℃; sp. gr. 4.81 at 20℃; valence −2, +4, or +6. Selenium is directly ...

(Encyclopedia) pitchblende pĭchˈblĕndˌ [key], dark, lustrous, heavy mineral, a source of radium and uranium. Largely natural uranium oxides, triuranium octaoxide (U3O8) and uranium dioxide (UO2), it usually cont...

(Encyclopedia) Mieres mēāˈrĕs [key], city (1990 pop. 57,627), Oviedo prov., N Spain, in Asturias, on the Lena River. It is an important mining center for coal, sulfur, and cinnabar and has iron and steel plants....

(Encyclopedia) Turner Valley, village (1991 pop. 1,352), SW Alta., Canada, at the foot of the Rocky Mts., on the Sheep River, SW of Calgary. It is in the center of the Turner Valley oil and natural gas fields, opene...

(Encyclopedia) Bagnères-de-Luchon bänyĕrˌ-də-lüshôNˈ [key], town, Haute-Garonne dept., S France, at the foot of the Maladetta Mts. It is an important resort in the Pyrenees. Its warm sulfur springs have been...

(Encyclopedia) dandruff, excessive flaking of skin from the scalp, apparent as dry or greasy diffuse scaling with variable itching. It is the sign of a skin disease, such as seborrhea or a fungal infection. Treatmen...

(Encyclopedia) silicon, nonmetallic chemical element; symbol Si; at. no. 14; interval in which at. wt. ranges 28.084–28.086; m.p. 1,410℃; b.p. 2,355℃; sp. gr. 2.33 at 25℃; valence usually +4. Silicon is the ...