- 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.
A group long recognized as an order of fossil plants (subdivision Psilopsida) collected in rocks of Late Silurian and Devonian age. It has been subdivided, on the basis of many data, into three categories whose descriptions include the chief kinds of plants formerly included in Psilophytales. Some authors will treat the three groups as classes under the division Rhyniophyta; others may prefer to consider them as three separate divisions of the subkingdom Embryobionta. They are given in this Encyclopedia as three classes of the division Rhyniophyta: Rhyniopsida, Zosterophyllopsida, and Trimerophytopsida.
Industry:Science
A group name for all clay minerals with an expanding structure, except vermiculite, and also a specific mineral name for the high alumina end member of the group.
Industry:Science
A group of 28 or more families of polychaete annelids in which the anterior, or cephalic, region is more or less completely concealed by overhanging peristomial structures, or the body is divided into an anterior thoracic and a posterior abdominal region; the pharynx or proboscis is usually soft and epithelial, lacking hard jaws or paragnaths.
Industry:Science
A group of 34 families of Polychaeta in which the anterior, or cephalic, region is more or less fully exposed and the body is often long, linear to short, and depressed. The segments of these worms are similar or change gradually. The pharynx is often heavily muscularized and eversible, and its inner walls are fortified with calcified or chitinized plates or jaws. Some families are benthic throughout their lives, others are entirely pelagic, and some have pelagic larval and reproductive stages and benthic trophic development. Errantia occur in all seas, at all depths, and in inland seas or lakes. They range in length from a few millimeters to 6 ft (2 m).
Industry:Science
A group of analytical techniques developed to continuously monitor physical or chemical changes of a sample which occur as the temperature of a sample is increased or decreased. Thermogravimetry, differential thermal analysis, and differential scanning calorimetry are the three principal thermoanalytical methods. Commercial instruments are available for all types of thermal analysis. Most instruments use modern computer technology to control the instrument while collecting and analyzing data.
Industry:Science
A group of antibiotics that are effective in eradicating streptococcal, pneumococcal, staphylococcal, <i>Klebsiella</i>, <i>Neisseria</i>, enteric gram-negative rod bacteria that produce pulmonary, skin and soft tissue, bone and joint, endocardial, surgical, urinary, and bacteremic infections. They have been used most often in a preventive or prophylactic fashion at the time of various surgical procedures. The pharmacology of the early cephalosporins was such that the agents had to be administered by vein in frequent intervals in serious infections. This problem was overcome since most of the newer agents have much longer half-lives. All the third-generation cephalosporins penetrate well into tissues, and antibacterially active levels in various body fluids (pleural, peritoneal, synovial, biliary) and tissues such as bone are excellent. The toxic potential of the agents, considering their broad antibacterial spectrum, has been minor. Toxicities which are seen are those of bleeding due to vitamin K depletion.
Industry:Science
A group of approximately 100 species of grass; more than 30 are represented in the United States. Tall fescue (<i>Festuca arundinacea</i>), a perennial cool-season plant introduced from Europe, occupies about 35×10<sup>6</sup> acres (15×10<sup>6</sup> hectares), primarily in the humid south-central region of the United States. It is popular because of its ease of establishment, vigor, wide range of adaptation, long grazing season, tolerance to abuse, sufferance of drought and poor soils, pest resistance, good seed production, and esthetic value when used for turf, ground cover, and conservation purposes. Its dominance of pastures and roadsides indicates that it fills an important ecological niche. It is used primarily as pasture and hay for beef cattle, with lesser use for dairy cows or replacement heifers, sheep, and horses. The leafy and vigorous plants can grow to 3–4 ft (0.9–1.2 m) if undisturbed; under grazing or clipping, they can form a dense sod when sufficient water and fertility are available.
Industry:Science
A group of branched, filamentous green algae, commonly known as the stoneworts, brittleworts, or muskgrasses, that occur mostly in fresh- or brackish-water habitats. They are important as significant components of the aquatic flora in some locales, providing food for waterfowl and protection for fish and other aquatic fauna; as excellent model systems for cell biological research; and as a unique group of green algae thought to be more closely related to the land plants.
Industry:Science
A group of chemical compounds in which all or a part of the molecular bonding is of the coordinate covalent type.
Industry:Science
A group of closely related polypyrrole compounds containing trivalent cobalt (see <b>illus.</b>); often called cobalamin. The vitamin is a dark-red crystalline compound; in aqueous solution and at room temperature it is most stable at pH 4–7.
Industry:Science
