- 行业: Printing & publishing
- Number of terms: 178089
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- 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.
An inborn error of metabolism in which affected individuals lack the liver enzyme phenylalanine hydroxylase (PAH), which is needed to metabolize phenylalanine, an amino acid essential for normal growth and development. If untreated, affected individuals may become severely mentally retarded, become microcephalic, have behavioral problems, develop epilepsy, or show other signs of neurological impairment. Phenylketonuria (PKU) is inherited as an autosomal recessive trait and is found in all ethnic groups but most frequently in individuals of northern European descent. Its incidence is about 1 per 14,000 births in the United States. Classically, persons with phenylketonuria exhibit blood phenylalanine concentrations of 20 mg/deciliter or more (normal concentrations are about 1–2 mg/dl), normal blood tyrosine levels, and excessive phenylalanine metabolites in the urine while on a normal diet. Phenylketonuria variants have blood phenylalanine concentrations of 10–20 mg/dl, but may not have phenylalanine metabolites in their urine unless they have ingested excessive amounts of protein.
Industry:Science
An incompletely known and poorly defined group of vascular plants whose geologic range extends from Upper Carboniferous to Triassic. Their taxonomic status and position in the plant kingdom are uncertain since morphological evidence (because of the paucity of the fossil record) does not make it possible to place the group confidently in any recognized major subdivision of the vascular plants. A rather heterogeneous assemblage of foliar and vegetative organs assignable to fairly well-defined genera have been placed in the group, thus somewhat forcing the concept that these parts constitute a natural order of vascular plants. Internal anatomy is unknown, with exception of the possible noeggerathialean genus <i>Sphenostrobus</i>. Noeggerathialean genera include <i>Noeggerathia, Noeggerathiostrobus, Tingia, Tingiostachya</i>, and <i>Discinites</i>. The reproductive organs are strobiloid, with whorled organization, and vary from homosporous to heterosporous. In <i>Discinites</i> the number of megaspores may range from 1 to 16 per sporangium. Foliar organs vary from nonarticulate and fernlike to anisophyllous four-ranked fronds. The Noeggerathiales have been proposed in the evolutionary scheme for vascular plants.
Industry:Science
An independent discipline applying the principles and methods of general microbiology to research in marine biology and biogeochemistry. Dealing, by definition, with organisms of microscopic dimensions, marine microbiology focuses primarily on prokaryotic organisms, mainly bacteria.
Industry:Science
An indicating instrument used in photography to determine lens aperture and shutter speed. An exposure meter may be used either in the darkroom to determine approximate printing time for a contact print or an enlargement or, more usually, with a camera to determine exposure of film.
Industry:Science
An individual animal or plant made up of cells derived from more than one zygote or otherwise genetically distinct.
Industry:Science
An induced state in which antigens originally regarded as foreign become regarded as self by the immune system. Tolerance can be induced (tolerization) in all of the cells of the immune system, including T cells (also known as T lymphocytes), the antibody-forming B cells (also known as B lymphocytes), and natural killer cells. Artificially induced immunological tolerance can be helpful in a number of clinical settings.
Industry:Science
An inductor that is used to prevent electric signals and energy from being transmitted along undesired paths or into inappropriate parts of an electric circuit or system. Power-supply chokes prevent alternating-current components, inherent to a power supply, from entering the electronic equipment. Radio-frequency chokes (RFCs) prevent radio-frequency signals from entering audio-frequency circuits. The printed circuit boards used in virtually all electronic equipment such as computers, television sets, and high-fidelity audio systems typically have one or more chokes. The purposes of these chokes are the (1) attenuation of spurious signals generated in the equipment itself so that these signals will not be transmitted to other parts of the circuit or beyond the overall system to other electronic devices; (2) prevention of undesired signals or electrical noise generated in other parts of the system from adversely affecting circuit performance; and (3) prevention of ripple from the power supply from degrading system behavior. Waveguide chokes keep microwave energy from being transmitted to the wrong part of a waveguide system.
Industry:Science
An industry, abbreviated CPI, in which the raw materials undergo chemical conversion during their processing into finished products, as well as (or instead of) the physical conversions common to industry in general. In the chemical process industry the products differ chemically from the raw materials as a result of undergoing one or more chemical reactions during the manufacturing process. The chemical process industries broadly include the traditional chemical industries, both organic and inorganic; the petroleum industry; the petrochemical industry, which produces the majority of plastics, synthetic fibers, and synthetic rubber from petroleum and natural-gas raw materials; and a series of allied industries in which chemical processing plays a substantial part. While the chemical process industries are primarily the realm of the chemical engineer and the chemist, they also involve a wide range of other scientific, engineering, and economic specialists.
Industry:Science
An infection by the plerocercoid, or sparganum, of certain species of the genus <i>Spirometra</i>. Members of this genus have a life cycle much like that of <i>Diphyllobothrium latum</i>. The adult normally occurs in the intestine of dogs and cats, the procercoid in copepods, and the plerocercoid in the musculature of frogs, snakes, or aquatic mammals, but not in fish. The whitish, unsegmented plerocercoid usually is an inch or so in length, but may reach a length of a foot or more. Humans may become infected accidentally by drinking water with infected copepods or by eating hosts containing plerocercoids. Since humans are not suitable hosts for the adult stage, the plerocercoids leave the gut and enter the musculature, body cavities, or other sites and remain as plerocercoids. In Eastern countries, freshly opened frogs are sometimes used as poultices on sores, particularly around the eyes, and if plerocercoids are present, they may invade the human tissues. Human sparganosis is rare in North America.
Industry:Science
An infection caused by anaerobic bacteria (organisms that are intolerant of oxygen). Most such infections are mixed, involving more than one anaerobe and often aerobic or facultative bacteria as well.
Industry:Science
