- 行业: Printing & publishing
- Number of terms: 178089
- Number of blossaries: 0
- Company Profile:
McGraw Hill Financial, Inc. is an American publicly traded corporation headquartered in Rockefeller Center in New York City. Its primary areas of business are financial, publishing, and business services.
A record of earlier life buried in rock. Originally meaning any distinctive object that has been dug up (from Latin <i>fodio</i>, dig), the term “fossil” soon came to refer particularly to things resembling animals and plants. These objects were known before it was recognized that life on Earth has a long history. They were generally interpreted as having somehow grown in the rock or been placed there by a creator, or as being remains of organisms living somewhere else at the time in undiscovered seclusion.
Industry:Science
A rectifying semiconductor device which converts electrical energy into electromagnetic radiation. The wavelength of the emitted radiation ranges from the near-ultraviolet to the near-infrared, that is, from about 400 to over 1500 nanometers.
Industry:Science
A reduction in the total quantity of hemoglobin or of red blood cells (erythrocytes) in the circulation. Because it generally is impractical to measure the total quantity, measures of concentration are used instead. Hemoglobin is contained in red blood cells, which are suspended in plasma, the liquid component of blood. Therefore, concentration is affected not only by quantities of hemoglobin and red blood cells but also by plasma volume. Thus, the apparent anemia found in many women in the third trimester of pregnancy is not really anemia at all: the red cell mass is actually increased, but the plasma volume is expanded even more. In other words, hemodilution is present. Conversely, in dehydration and other circumstances of hemoconcentration, the plasma volume is reduced, thereby tending to mask anemia.
Industry:Science
A reference elevation of the sea surface from which vertical measurements are made, such as depths of the ocean and heights of the land. The intersection of the elevation of a tidal datum with the sloping shore forms a line used as a horizontal boundary. In turn, this line is also a reference from which horizontal measurements are made for the construction of additional coastal and marine boundaries.
Industry:Science
A refined petroleum fraction used as a fuel for heating and cooking, jet engines, lamps, and weed burning, and as a base for insecticides. Kerosine, known also as lamp oil, is recovered from crude oil by distillation. It boils in the approximate range of 350–550°F (180–290°C). Most marketed grades, however, have narrower boiling ranges. The specific gravity is about 0.8. Determined by the Abel tester, the flash point is not below 73°F (23°C), but usually a higher flash point is specified. Down to a temperature of −25°F (−32°C), kerosine remains in the liquid phase. Components are mainly paraffinic and naphthenic hydrocarbons which are in the C<sub>10</sub>–C<sub>14</sub> range. A low content of aromatics is desirable except when kerosine is used as tractor fuel.
Industry:Science
A region in a solid within which elementary atomic or molecular magnetic or electric moments are uniformly aligned.
Industry:Science
A region of darkness caused by the presence of an opaque object interposed between such a region and a source of light. A shadow can be totally dark only in that part called the umbra, in which all parts of the source are screened off. With a point source, the entire shadow consists of an umbra, since there can be no region in which only part of the source is eclipsed. If the source has an appreciable extent, however, there exists a transition surrounding the umbra, called the penumbra, which is illuminated by only part of the source. Depending on what fraction of the source is exposed, the illumination in the penumbra varies from zero at the edge of the full shadow to the maximum where the entire source is exposed. The edge of the umbra is not perfectly sharp, even with an ideal point source, because of the wave character of light.
Industry:Science
A relationship between two different species of organisms in which the larger, or host, organism transports a smaller organism, the guest. It is regarded as a type of commensalism in which the relationship is limited to transportation of the guest. The term is credited to P. Lesne following his observations on the biology of a small fly, <i>Limosina sacra</i>, which is transported by a scarabeid, one of the dung beetles, into its burrow. These burrows are suitable breeding sites for both animals.
Industry:Science
A relationship between two or more quantities which can be expressed in terms of linear algebraic, differential, or integral equations. A system in which all quantities (or variables) can be described in terms of such equations is said to be a linear system. By definition, linear systems satisfy the principle of superposition. By this principle, the response of a linear system to multiple inputs is given simply by the sum of the responses due to each individual input. In addition, if all inputs are multiplied by a common constant factor, the resulting response is multiplied by the same factor.
Industry:Science
