- 行业: Printing & publishing
- Number of terms: 178089
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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.
The big bang model of the universe makes a number of profound and testable predictions. In a uniformly expanding universe, galaxies would have been closer together in the past. Early in the universe, the density (and temperature) of matter would therefore have been very high. The discovery of the expansion of the universe by E. Hubble in 1929, the discovery of a (now) cool remnant cosmic background radiation by A. Penzias and R. W. Wilson in 1965, and the observed relative abundances of the lightest elements (notably, hydrogen and helium) provide compelling evidence in support of the big bang model.
Industry:Science
The brightest star in the northern sky, apparent magnitude −0.05, also known as α Boötis. It is a yellow giant star of spectral type K1.5, one of the nearest giants to the Earth at a distance of 11.25 parsecs (2.16 × 10<sup>14</sup> mi or 3.47 × 10<sup>14</sup> km). Unlike the Sun, which is currently converting hydrogen into helium in its core, Arcturus has already exhausted its central hydrogen and has evolved away from the main sequence. It is approximately 25 times larger in diameter than the Sun, and more than 100 times more luminous. Its effective temperature is estimated to be 7700°F (4300 K).
Industry:Science
The development and analysis of computational methods (and ultimately of program packages) for the minimization and the approximation of functions, and for the approximate solution of equations, such as linear or nonlinear (systems of) equations and differential or integral equations. Originally part of every mathematician's work, the subject is now often taught in computer science departments because of the tremendous impact which computers have had on its development. Research focuses mainly on the numerical solution of (nonlinear) partial differential equations and the minimization of functions.
Industry:Science
The “hygiene hypothesis,” sometimes referred to as the “old friends hypothesis,” is that humans have evolved with certain intestinal bacteria and worms whose presence can “train” the immune system not to overreact against harmless commensal organisms. As people have become more prosperous and are leading “healthier” lifestyles, these organisms have been lost from the intestines, and the immune system is losing its natural balance. This predicts a significant increase in immune diseases, both allergic and autoimmune, which in fact has been observed in the developed world over the last several decades.
Industry:Science
The formation of a new plant that is either an exact copy or recombination of the genetic makeup of its parents. There are three types of plant reproduction considered here: (1) vegetative reproduction, in which a vegetative organ forms a clone of the parent; (2) asexual reproduction, in which reproductive components undergo a nonsexual form of production of offspring without genetic rearrangement, also known as apomixis; and (3) sexual reproduction, in which meiosis (reduction division) leads to formation of male and female gametes that combine through syngamy (union of gametes) to produce offspring.
Industry:Science
Spatial layout is an integral part of the process of facilities planning. Facilities planning is concerned with how a specific activity can best be used to obtain a specific goal. One such activity is manufacturing, where the goal is the fabrication of a product. Facilities planning can be divided into a location component and a design component. The latter can be subdivided into systems design, spatial layout design, and material-handling design. Because of the complexity of the problem of facilities planning, each component is usually studied individually and then integrated into the complete system.
Industry:Science
The increase of air temperature with height; an atmospheric layer in which the upper portion is warmer than the lower. Such an increase is opposite, or inverse, to the usual decrease of temperature with height, or lapse rate, in the troposphere of about 3.3°F/1000 ft (6.5°C/km) and somewhat less on mountain slopes. However, above the tropopause, temperature increases with height throughout the stratosphere, decreases in the mesosphere, and increases again in the thermosphere. Thus inversion conditions prevail throughout much of the atmosphere much or all of the time, and are not unusual or abnormal.
Industry:Science
The accumulated body of scientific-technical writings published to serve the informational needs of, primarily, scientists, engineers, and research workers, and, to the extent that it can be understood, the general public. This vast literature is worldwide in origin, international in language, diverse in subject content, varied in form, uneven in quality, and expensive. An ever-increasing portion of it is being produced, stored, and retrieved or published electronically, and is being made available on film, tape, CD-ROM or magnetic disk, or through remote terminals as well as in print-on-paper format.
Industry:Science
The chemical reaction of hydrogen with another substance, generally an unsaturated organic compound, and usually under the influence of temperature, pressure, and catalysts. There are several types of hydrogenation reactions. They include (1) the addition of hydrogen to reactive molecules; (2) the incorporation of hydrogen accompanied by cleavage of the starting molecules (hydrogenolysis); and (3) reactions in which isomerization, cyclization, and so on, result. Other reactions that involve molecular hydrogen and catalysts are reductive amination (hydroammonolysis) and hydroformylation (oxo reaction).
Industry:Science
The first 3 billion years of evolution saw the origin of life itself, the diversification of bacterial lineages, the origin and diversification of eukaryotes, and the appearance of many lineages of multicelled life, including animals. This time span culminated in the Cambrian explosion of complex metazoan organisms, but the fuse to the explosion was lit well before the start of the Cambrian (about 540 million years ago). Coupled with these events were major geologic events, such as the origin of the Earth's atmosphere and the appearance of tectonic plates, that profoundly influenced the history of life.
Industry:Science
