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anticoagulant

(Encyclopedia)anticoagulant ănˌtēkōăgˈyələnt [key], any of several substances that inhibit blood clot formation (see blood clotting). Some anticoagulants, such as the coumarin derivatives bishydroxycoumarin...

Hay-Herrán Treaty

(Encyclopedia)Hay-Herrán Treaty hā-ĕränˈ [key], 1903, aborted agreement between the United States and Colombia providing for U.S. control of the prospective Panama Canal and for U.S. acquisition of a canal zon...

heartburn

(Encyclopedia)heartburn, burning sensation beneath the breastbone, also called pyrosis. Heartburn does not indicate heart malfunction but results from nervous tension or overindulgence in food or drink. The sensati...

Jefferson, Territory of

(Encyclopedia)Jefferson, Territory of, in U.S. history, region that roughly encompassed the present-day state of Colorado, although extending 2° farther south and 1° farther north, organized by its inhabitants (1...

plant breeding

(Encyclopedia)plant breeding, science of altering the genetic pattern of plants in order to increase their value. Increased crop yield is the primary aim of most plant-breeding programs; advantages of the hybrids a...

Prairie Pothole Region

(Encyclopedia)Prairie Pothole Region, large geographic area of central North America consisting of grass-covered wetlands. Stretching northwest from N Iowa through SW Minnesota, E South Dakota, E and N North Dakota...

Robert of Geneva

(Encyclopedia)Robert of Geneva, d. 1394, Genevan churchman, antipope (1378–94; see Schism, Great) with the name Clement VII. He was archbishop of Cambrai (1368) and was created (1371) a cardinal. He was subsequen...

Vallejo

(Encyclopedia)Vallejo vălāˈhō, –lāˈō, və– [key], city (1990 pop. 109,199), Solano co., W Calif., on San Pablo Bay at the mouth of the Napa River; inc. 1866. It is a port and a trade and processing cente...

airfoil

(Encyclopedia)airfoil, surface designed to develop a desired force by reaction with a fluid, especially air, that is flowing across the surface. For example, the fixed wing surfaces of an airplane produce lift, whi...

gunpowder

(Encyclopedia)gunpowder, explosive mixture; its most common formula, called “black powder,” is a combination of saltpeter, sulfur, and carbon in the form of charcoal. Historically, the relative amounts of the c...