- 行业: Printing & publishing
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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.
Recent research has produced a wealth of information on deoxyribonucleic acid sequences, their role in human disease, and their antimicrobial properties. This article discusses three aspects: (1) A new electrochemical technique has been developed for detecting DNA hybridization, determining DNA sequences, and identifying genes. (2) DNA helicase enzymes can mutate and lead to human disease. (3) A modified form of DNA that mimics transfer ribonucleic acid (tRNA) and can block tRNA binding has potential as a new type of antibiotic.
Industry:Science
Scientific satellites are used to gain basic knowledge. They may be satellites of Earth or of other planets or their moons. Satellites used to apply space knowledge and techniques to practical purposes are called applications satellites. Many spacecraft are used for multiple purposes, combining space exploration, science, and applications in various ways. Scientific satellites are often called research satellites, and applications satellites are commonly designated by the application field, for example, navigation satellites.
Industry:Science
Soil—the thin, unconsolidated, vertically differentiated portion of the Earth's surface—is ubiquitous and often ignored despite its many important environmental and life-sustaining functions. Soil is necessary for the production of food, feed, and fiber products, and supports buildings, roads, and playing fields. Soil helps to safely dispose of and process biological and industrial wastes, and it purifies and filters water that may enter drinking water supplies. Usually, soil performs more than one of these roles simultaneously.
Industry:Science
In split genes, a portion that is included in the ribonucleic acid (RNA) transcript of a gene and survives processing of the RNA in the cell nucleus to become part of a spliced messenger RNA (mRNA) or structural RNA in the cell cytoplasm. Split genes are those in which regions that are represented in mature mRNAs or structural RNAs (exons) are separated by regions that are transcribed along with exons in the primary RNA products of genes, but are removed from within the primary RNA molecule during RNA processing steps (introns).
Industry:Science
In the flowers of many plant species, pollen sacs contain tiny granules (mostly smaller than 4 micrometers) called orbicules, or Ubisch bodies, along with the pollen. The orbicules are sometimes in close contact with the pollen grains and can be dispersed into the atmosphere when the pollen is released from the flower's anthers. Although their function in the plant remains unknown, orbicules may prove useful as phylogenetic markers, and recent studies suggest that they may play a role in allergic reactions associated with pollen.
Industry:Science
Peroxynitrite chemistry, a century-old area of research, has experienced a renaissance with the annual number of publications on the subject increasing from only one in 1990 to nearly 200 in 1998–2000. This renewed interest was stimulated by the discovery of the biological roles of nitric oxide, distinguished by the 1998 Nobel prize, and the recognition that the conversion of nitric oxide into peroxynitrite may play a major role in human diseases associated with oxidative stress and in cellular defense against invading pathogens.
Industry:Science
Meteor storms are spectacular events which occur rarely—only a few were observed in the twentieth century. The problem of reliably predicting them has occupied solar system scientists since the unexpected and astonishing Leonid meteor display of 1833. Advances in understanding the phenomenon, with determinations of exactly when and from which parts of the world displays would be visible, allowed a number of storms to be widely observed recently in the years following the latest return of the Leonids' parent comet 55P/Tempel-Tuttle.
Industry:Science
In recent years motor racing has become one of the most popular of sports, attracting record numbers of followers. In some racing categories the vehicles resemble production sedans while in others they look more like fighter airplanes, and there is also a great variety of tracks that range from paved to unpaved and from straight to oval or regular road courses. In all forms of racing, however, aerodynamics eventually surfaced as a significant design parameter, and nowadays all race-car designs have some level of aerodynamic element.
Industry:Science
Inorganic, nonmetallic materials processed or consolidated at high temperature. This definition includes a wide range of materials known as advanced ceramics and is much broader than the common dictionary definition, which includes only pottery, tile, porcelain, and so forth. The classes of materials generally considered to be ceramics are oxides, nitrides, borides, carbides, silicides, and sulfides. Intermetallic compounds such as aluminides and beryllides are also considered ceramics, as are phosphides, antimonides, and arsenides.
Industry:Science
Light which has its electric vector oriented in a predictable fashion with respect to the propagation direction. In unpolarized light, the vector is oriented in a random, unpredictable fashion. Even in short time intervals, it appears to be oriented in all directions with equal probability. Most light sources seem to be partially polarized so that some fraction of the light is polarized and the remainder unpolarized. It is actually more difficult to produce a completely unpolarized beam of light than one which is completely polarized.
Industry:Science
