- 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.
A group of common ferromagnesian silicate minerals that occur as major or minor constituents in a wide variety of rocks. The crystal structure of the amphiboles is very flexible and, as a result, the amphiboles show a larger range of chemical composition than any other group of minerals. The structural and chemical complexity of the amphiboles reveals considerable information on the geological processes that have affected the rocks in which they occur.
Industry:Science
A group of composite materials consisting of an intimate mixture of ceramic and metallic components.
Industry:Science
A group of compounds derived from 2-methyl-1,4-naphthoquinone that prevent bleeding in mammals and birds. Vitamin K<sub>1</sub> (phylloquinone) is produced by green plants; a related form, vitamin K<sub>2</sub> (menaquinone), is produced by intestinal bacteria. Chemically synthesized forms include vitamin K<sub>1</sub>, K<sub>2</sub>, and menadione (vitamin K<sub>3</sub>). All of these compounds are fat-soluble liquids at room temperature that become biologically inactive when exposed to light or alkali.
Industry:Science
A group of deuterostome animals that includes the classes Enteropneusta, Pterobranchia, and Planctosphaeroidea. The last, a monospecific class, is represented by <i>Planctosphaera pelagica</i>, a planktonic larva that occupies low depths and resembles the larval tornaria of Enteropneusta.
Industry:Science
A group of diseases affecting joints or their component tissues. Several types of arthritis are recognized, and these can be divided into groups by their clinical course and pathologic appearance.
Industry:Science
A group of distinct genes that are expressed and regulated as a unit. Each operon is a DNA sequence that is composed of a tightly linked cluster of genes. At the 5′ end of the gene cluster is a promoter, the site at which RNA polymerase binds to begin transcription. RNA polymerase moves down the operon, catalyzing the synthesis of an RNA molecule with a sequence complementary to DNA. Some operons contain additional promoters between genes in the operon. Only genes on the 3′ sides of these promoters are transcribed from these internal sites.
Industry:Science
A group of distinct psychiatric disorders (including generalized anxiety disorder, panic disorder, obsessive-compulsive disorder, social anxiety disorder, and posttraumatic stress disorder) that are characterized by marked distress and impairment of functioning. Fear is an adaptive emotion that is seen in many animal species, while anxiety can be viewed as the subjective component of fear and, therefore, a normal emotion selected for by evolutionary processes. Anxiety disorders are among the most prevalent, disabling, and costly of psychiatric disorders. They are frequently underrecognized and undertreated. Fortunately, there is growing understanding of the mechanisms underlying these disorders, and a number of effective treatments are available.
Industry:Science
A group of drugs widely used for the suppression of anxiety, the induction of sleep, and the control of seizures. Some of them, when injected intravenously, produce a general anesthesia.
Industry:Science
A group of entoparasites considered to be a subclass or order of the Trematoda. They have strongly developed ventral holdfasts whose alveolations are taxonomically important. Two families, Aspidogastridae and Stichocotylidae, are recognized. Aspidogastridae, which are the commonest, occur in various cavities of mollusks and in digestive tracts of fishes and turtles. Development is usually direct, involving nonciliated juveniles and one host. Fishes and turtles probably acquire infestations of adult worms by ingesting parasitized mollusks. Elongate Stichocotylidae have a single row of alveoli and occur in the digestive tracts of skates. Juvenile <i>Stichocotyle nephrops</i> encyst in lobsters and develop to maturity after ingestion by skates, thus approaching the digeneid life cycle. Little is known of the physiology of aspidogastreids, but they appear less host-specific than other trematodes.
Industry:Science
A group of eukaryotic microorganisms traditionally classified as one of the five animal kingdoms. Although the name signifies primitive animals, some protozoa (phytoflagellates and slime molds) show enough plantlike characteristics to justify claims that they are plants. This apparent conflict may be reconciled to some extent by considering protozoa as descendants of microorganisms which preceded plants and animals. Such an assumption might account for <i>Euglena gracilis</i>, a green flagellate which can fix carbon dioxide (CO<sub>2</sub>) in light as algae do but, unlike algae, can also carry on a plantlike fixation in darkness. In addition, <i>E</i>. <i>gracilis</i> can fix carbon dioxide by pathways characteristic of animals. Inclusion of such metabolically unspecialized organisms, along with certain photoautotrophic chlorophyll-bearing species, might imply that the phylum is partly an arrangement for taxonomic convenience rather than a phylogenetically homogeneous group.
Industry:Science
