- 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 process by which the cellular elements of the blood are formed. Blood contains many free-floating cells which are moved throughout the body within the blood vessels. The three main types of cells are the red cells (erythrocytes), which serve to carry oxygen, the white cells (leukocytes), which function in the prevention of and recovery from disease, and the thrombocytes, which function in blood clotting. In humans there is only one white cell in the blood for every 700 red cells.
Industry:Science
The process of causing a body to move by exerting a force against it. Propulsion is based on the reaction principle, stated qualitatively in Newton's third law, that for every action there is an equal and opposite reaction. A quantitative description of the propulsive force exerted on a body is given by Newton's second law, which states that the force applied to any body is equal to the rate of change of momentum of that body, and is exerted in the same direction as the momentum change.
Industry:Science
The mechanism by which cells in a multicellular organism become specialized to perform specific functions in a variety of tissues and organs. The life cycle of a higher organism begins with a unicellular stage, the fertilized egg, and becomes more complex as the individual grows and takes on its characteristic form. The life cycle of a unicellular organism permits temporary change in shape and chemical composition. Only a multicellular organism can afford irreversibly differentiated cells.
Industry:Science
The separation, extraction, and purification of alumina from ores, followed by the production of aluminum. Aluminum is the most abundant metallic element on the Earth and Moon but is never found free in nature. It makes up more than 8% of the solid portion of the Earth's surface. Seawater contains an average of only 0.5 ppm aluminum. The element is widely distributed in plants, where it may be present in significant concentrations, particularly in vegetation in marshy places and acid soils.
Industry:Science
The study of extrasolar planets has become one of the most active fields of research in astronomy since the discovery in 1995 of several giant planets orbiting nearby stars similar to the Sun. There have been many unexpected results, and the progress has been remarkable. More than 100 planets are now known, many of them in systems of two or more bodies orbiting the same star. In one case it has even been possible to detect the atmosphere of the planet as it transits between us and its star.
Industry:Science
The parallel of latitude about 23½° (23.45°) north of the Equator. The importance of this line lies in the fact that its degree of angle from the Equator is the same as the inclination of the Earth's axis from the vertical to the plane of the ecliptic. Because of this inclination of the axis and the revolution of the Earth in its orbit, the vertical overhead rays of the Sun may progress as far north as 23½°. At no place north of the Tropic of Cancer will the Sun, at noon, be 90° overhead.
Industry:Science
The plant <i>Manihot esculenta</i> (family Euphorbiaceae), also called manioc. It is one of the 10 most important food plants, and the most important starchy root or tuber of the tropics. It originated in Central or South America, possibly Brazil, and was domesticated and widely distributed well before the time of Columbus. Subsequent distribution has established cassava as a major crop in eastern and western Africa, in India, and in Indonesia. Brazil continues to be the largest producer.
Industry:Science
The name given by G. Cuvier in 1817 to an assemblage of echinoids in which the anus and periproct lie within the apical system. The test is globular and preponderantly radially symmetrical, and the ambulacral plates are commonly compound. The group included, in effect, all those echinoids which did not fall in the Irregularia. The Irregularia, however, were shown to be polyphyletic by J. Durham and R. Melville in 1957, and so neither the Irregularia nor the Regularia constitute valid taxa.
Industry:Science
The system of rocks deposited during the middle part of the Mesozoic Era, and encompassing an interval of time between about 200 and 142 million years ago, based on radiometric dating. It takes its name from the Jura Mountains of Switzerland. Its rich marine invertebrate faunas in western Europe have been the subject of intensive study since the pioneering days of geology in the early nineteenth century, and provided the basis for the fundamental stratigraphic concepts of stages and biozones.
Industry:Science
The study of the development or morphogenesis and growth of the invertebrates. The same general principles of development apply to the invertebrates as do to the vertebrates. Actually, much of the basic knowledge of embryology has been the result of studies on the invertebrates. A common phenomenon in the invertebrates is the release of a free and independent form, the larva, before development is completed. The larvae vary considerably and are characteristic of the different animal groups.
Industry:Science
