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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 sinusoidal quantity having a frequency that is an integral multiple of the frequency of a periodic quantity to which it is related.
Industry:Science
A slow change in the direction of the axis of rotation of the Earth, and also a very small change in the orientation of the Earth's orbit around the Sun. Thus, both the celestial equator (the projection of the terrestrial equator onto the sky) and the ecliptic (the projection of the Earth's orbit onto the sky) move slowly in time, and, consequently, so do their intersections, the vernal and autumnal equinoxes.
Industry:Science
A slowly progressive diarrheal disease that causes major economic loss to the cattle industry; also known as paratuberculosis. It is caused by <i>Mycobacterium avium ss paratuberculosis (MAP)</i>, which produces chronic inflammation of the mucosa of the ileocecal valve and adjacent tissues of the gastrointestinal tract of cattle, sheep, goats, and wild ruminants. The organism has been isolated from 2–3% of the adult cows in the United States; in some exotic species (such as mouflon and mountain goats), more than 90% of the animals in a herd may be infected. Animals less than 2 months of age are most susceptible to infection. Therefore, eliminating or minimizing exposure of young animals to <i>MAP</i> is important in the control of Johne's disease. It is recommended that calves be removed from dams immediately after birth and fed colostrum from negative animals.
Industry:Science
A small and distinctive order of valvatacean Asteroidea with long, straight-sided arms and relatively small disks. The skeleton is differentiated into marginals, actinals, and abactinals, and there is a clear calycinal ring. Both supra- and inframarginals are present and are offset or alternate rather than vertically aligned as they are in other asteroids. Intermarginal ossicles are not present. On the oral surface the longest actinal row lies adjacent to the ambulacral groove. Digestive and reproductive organs are confined to the disk and most proximal parts of the arms and do not extend well into the arms as in other valvataceans. Dorsal longitudinal muscle bands lie free within the arms and are anchored into the body wall only at their distal and proximal ends.
Industry:Science
A small class of “arm”- and brachiole-bearing, stemmed echinoderms in the subphylum Crinozoa, based on five genera known from the Middle Ordo-vician to Late Silurian of Europe and North America. Coronoids have a crested theca or body with well-developed pentameral symmetry and plate arrangement very similar to that found in blastoids (see <b>illus.</b>). Skeletal plates include three basals (two large and one smaller), five radials extending up to form the crests and bearing central notches for the ambulacra, five small plates supporting the arms, and four regular deltoids plus two anal deltoids in the fifth position around the mouth. The mouth is central on top of the theca and has five ambulacral grooves radiating from it. A coiled arm is attached to a mounting plate at the end of each ambulacral groove; each arm has biserial plating with smaller biserial branches (= brachioles) on both sides. The projecting crests have internal canals that connected with the body cavity and apparently served as respiratory structures. A thin stem supported the theca above the sea floor, allowing coronoids to live as attached, low- to medium-level suspension feeders. Coronoids had previously been assigned to the blastoids, eocrinoids, or crinoids by different researchers, but they have been elevated in rank to a separate class. Coronoids appear to be most closely related to the Blastoidea and may have been the ancestors of this class.
Industry:Science
A small class of biflagellate unicellular algae (cryptomonads) in the chlorophyll <i>a–c</i> phyletic line (Chromophycota). In protozoological classification, these organisms constitute an order, Cryptomonadida, of the class Phytomastigophora. Cryptomonads are 4–80 micrometers long, ovoid or bean-shaped, and dorsoventrally flattened. The cell is bounded by a moderately flexible periplast comprising the plasmalemma and underlying rectangular or polygonal proteinaceous plates. A tubular invagination (gullet, groove, or furrow) traverses the ventral cytoplasm and opens just below the apex of the cell. A pair of subequal flagella, which are covered with hairs and small scales, arise from the center or apical end of the gullet.
Industry:Science
A small class of mostly motile, photosynthetic, unicellular algae in the chlorophyll <i>a</i>-<i>b</i> phyletic line (Chlorophycota). It is segregated from the Chlorophyceae primarily on the basis of ultrastructural characters, especially the possession of one or more layers of polysaccharide scales outside the plasmalemma. Prasinophytes are mainly members of the marine plankton, but they are also found in brackish- and fresh-water habitats. A few are benthic, with both coccoid and colonial forms known, while others live symbiotically within dinoflagellates, radiolarians, and turbellarian worms. Approximately 180 species are known in 13 genera.
Industry:Science
A small class of nonmotile, photosynthetic, unicellular algae, segregated from the class Xanthophyceae (Tribophyceae) on the basis of cytological, ultrastructural, and biochemical features of the vegetative cell and zoospore. Because of their lack of chlorophyll <i>b</i>, these organisms may be placed in the division Chromophycota, but their lack of chlorophyll <i>c</i>, in contrast to other chromophytes, supports recognition at a higher level (such as the division Eustigmatophyta). Only a dozen species in three genera are known. These live chiefly in fresh water, but also in marine habitats and in soil.
Industry:Science
A small class of poorly known biflagellate unicellular algae (raphidomonads) in the chlorophyll <i>a</i>–<i>c</i> phyletic line (Chromophycota). It is sometimes called Chloromonadophyceae, and its members called chloromonads, but this nomenclature is confusing because it calls to mind <i>Chloromonas</i>, a totally unrelated genus of green algae (Chlorophyceae). The alternative nomenclature used here is derived from <i>Raphidomonas</i>, a generic name within the class.
Industry:Science
A small class of primitive echinoderms (subphylum Echinozoa) known from the single species <i>Camptostroma roddyi</i> based on about 200 specimens from the Early Cambrian (<i>Bonnia-Olenellus</i> Zone) in southeastern Pennsylvania. <i>Camptostroma</i> was originally described as a hydrozoan or jellyfish, but it was recognized as an echinoderm and the new class Camptostromatoidea was set up for it. <i>Camptostroma</i> has been reinterpreted as an early edrioasteroid, and as a “stem echinoderm” ancestral to several other groups including edrioasteroids. Because of <i>Camptostroma</i>'s puzzling morphology, different reconstructions of it have been made (see <b>illus.</b>). It has a conical or domal theca or body with a nearly circular outline, divided into a pleated lower theca with larger and smaller overlapping plates, and a domed upper theca made up of large plates with pores on their margins surrounded by numerous smaller plates. The upper theca bears five straight to curved ambulacra protected by numerous cover plates and radiating from the central mouth, and a small anal pyramid at one edge. <i>Camptostroma</i> probably had the lower theca either embedded in the soft sediment or attached to objects lying on the sea floor, making it a stationary or attached, low-level suspension feeder using tube feet in the ambulacra to capture small food particles drifting by the theca. The unusual thecal plating is the main feature separating <i>Camptostroma</i> from later Edrioasteroidea, which it otherwise resembles, but this genus may also have been ancestral to other classes such as the Eocrinoidea.
Industry:Science
