- 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.
Since life first appeared on Earth some 3500 million years ago, species have been evolving from one another to create the diversity that is seen today. An analogy between this branching pattern of evolution and the growth of a tree has been popular since the time of C. Darwin—thus the “tree of life” metaphor. Phylogeny is the study of how species are related to one another and involves reconstructing or mapping the historical pattern of branching that best explains the patterns of similarity among organisms.
Industry:Science
Radio-echo sounding (RES) is a technique used by glaciologists to measure the internal structure, ice thickness, and subice morphology of ice masses. It has been used extensively in Greenland and Antarctica to determine the volume of ice stored within large ice sheets, and in numerous locations to build an understanding of the sizes of smaller ice caps and glaciers. Such information has been central to quantifying the rise in global sea level that might occur through future climate warming and glacier melting.
Industry:Science
Laboratory-based arson investigation is usually limited to the chemical analysis of fire debris, which is used to support field investigators who determine whether a fire is intentional (arson) or accidental. A gap has existed between the field investigators, most of whom have practical experience but a limited understanding of scientific principles, and the scientists and engineers who perform laboratory experiments to verify the hypotheses of the field investigators. This gap, however, is gradually narrowing.
Industry:Science
In serology, the combination of a toxic antigen with its corresponding antitoxin. If the antitoxin is derived from any species other than the horse, precipitation occurs over a wide range of reactant ratios, as in other antigen-antibody reactions. With horse antitoxin, flocculation occurs only if toxin and antitoxin are near equivalence, a twofold excess of either reactant giving soluble complexes. In most instances, the reaction results in partial or complete neutralization of the toxic activity of the antigen.
Industry:Science
Mycorrhizal fungi are ecologically significant because they form symbiotic relationships in and on the roots of host plants. The host plant provides the fungus with a soluble carbon source, and the fungus provides the host plant with an increased capacity to absorb water and nutrients from the soil. Thus, both partners benefit from this relationship. It has been found that the majority of plants do have mycorrhizal fungi associated with them; some of these associations are very specific while others are very broad.
Industry:Science
Luminous intensity expressed in candelas. The term refers only to the intensity in a particular direction and by itself does not give an indication of the total light emitted. The candlepower in a given direction from a light source is equal to the illumination in footcandles falling on a surface normal to that direction, multiplied by the square of the distance from the light source in feet. The candlepower is also equal to the illumination of metercandles (lux) multiplied by the square of the distance in meters.
Industry:Science
Manipulating data in the form of an image through several possible techniques. An image is usually interpreted as a two-dimensional array of brightness values, and is most familiarly represented by such patterns as those of a photographic print, slide, television screen, or movie screen. An image can be processed optically, or digitally with a computer. This article focuses on digital processing of an image to perform one of five tasks: enhancement, restoration, compression, image fusion, or automated image analysis.
Industry:Science
Proteins are large organic molecules that are involved in all aspects of cell structure and function. Proteins are made up of polypeptide chains, each constructed from a basic set of 20 amino acids, covalently linked in specific sequences. Each amino acid is coded by three successive nucleotide residues in deoxyribonucleic acid (DNA); the sequence of amino acids in a polypeptide chain, which determines the structure and function of the protein molecule, is thus specified by a sequence of nucleotide residues in DNA.
Industry:Science
In mechanics, nutation is a bobbing motion that accompanies the precession of a spinning rigid body, such as a top. Astronomical nutation refers to irregularities in the precessional motion of rotating bodies. A well-studied example is the irregularities in the precessional motion of the equinoxes caused by the varying torque applied to the Earth by the Sun and Moon. Astronomical nutation should not be confused with nutation as defined in mechanics; the latter is present even if the source of the torques is unvarying.
Industry:Science
Paleopathology is the study of diseases and disease processes in ancient individuals and populations, both human and animal. Justification for the study of paleopathology is threefold: information on disease processes for any era contributes to the overall body of medical knowledge; information about diseases in ancient populations can help to elucidate historical and paleontological questions; and differences in lesions and incidence between ancient and modern populations can help answer questions of modern pathology.
Industry:Science
