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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 small extinct order of the class Lycopsida that bridges the evolutionary gap between the primitive Zosterophyllopsida and relatively advanced Lycopsida; hence the asteroxylaleans are often termed prelycopsids. The best-known asteroxylalean species are of Early Devonian age, although similar forms survived to the Late Devonian. All possessed at least some hydrophytic features; together with a paucity of strengthening tissues, this characteristic suggests that they largely relied on hydrostatic pressure for structural support.
Industry:Science
A small fruit represented by about six species of the genus <i>Ribes</i> of the plant order Rosales. The gooseberry is a thorny, spreading bush which grows to a height of about 3 ft (0.9 m) and produces red, yellow, or green berries (see <b>illus.</b>). The most desirable hardier types in the United States are of American parentage, or are hybrids between American and European species. Commercial culture has declined and is limited to a few states, notably Oregon, Michigan, and Washington, but gooseberries are found in home gardens throughout most of the United States except the far South and Southwest.
Industry:Science
A small group of insects usually considered to constitute an order. They are commonly known as the sucking lice. All are parasites living in the covering hair of mammals. About 250 species are now known, and these comprise probably about half of the species in the world, but the group is known in detail to few persons.
Industry:Science
A small group of marine reptiles forming part of the Sauropterygia, known only from deposits of Triassic age in Europe, the Near East (Israel), North Africa (Tunisia), and China. The earliest occurrence of placodonts is in the uppermost Lower Triassic (upper Buntsandstein) of Upper Silesia (Poland); their latest occurrence is in the very late Triassic (Rhaetian) of the Southern Alps. Placodonts are reptiles with a grossly specialized dentition—flat-crowned teeth located in both the upper and lower jaws and on the palate—that functioned as a crushing device for hard-shelled invertebrate prey such as brachiopods, gastropods, clams, and cephalopods (see <b>illustration</b>).
Industry:Science
A small group of unsegmented, wormlike, marine animals once linked with the Sipuncula and Priapulida under the taxon Gephyrea. Since 1940, echiurans have been regarded as a separate phylum of the animal kingdom with affinities to the segmented annelid worms. They range from the tropical to the polar seas, burrowing in sea-floor sediments from the intertidal area to depths of 30,000 ft (9140 m).
Industry:Science
A small infectious agent that is unable to replicate outside a living animal cell. Unlike other intracellular obligatory parasites (for example, chlamydiae and rickettsiae), they contain only one kind of nucleic acid, either deoxyribonucleic acid (DNA) or ribonucleic acid (RNA), but not both. They do not replicate by binary fission. Instead, they divert the host cell's metabolism into synthesizing viral building blocks, which then self-assemble into new virus particles that are released into the environment. During the process of this synthesis, viruses utilize cellular metabolic energy, many cellular enzymes, and organelles which they themselves are unable to produce. For this reason they are incapable of sustaining an independent synthesis of their own components. Animal viruses are not susceptible to the action of antibiotics. The extracellular virus particle is called a virion, while the name virus is reserved for various phases of the intracellular development.
Industry:Science
A small order of aquatic birds that contains a single living family, the Gaviidae (loons), with five species restricted to the Northern Hemisphere, and a fossil family, the Colymboididae.
Industry:Science
A small order of aquatic birds that contains only a single living family, the Podicipedidae (grebes), with 20 species found throughout the world. They breed on freshwater, but some species winter along the coasts. Grebes have a number of convergent similarities with loons, but are not related to them or to the fossil hesperornithiforms. The close affinities of the grebes are still unresolved.
Industry:Science
A small order of birds containing only the family Coliidae with six species (the mousebirds) restricted to Africa. Mousebirds, or colies, are small, grayish to brownish, with a crest on the head and long tail (see <b>illustration</b>). The legs are short and the feet strong, with the four toes movable into many positions, from all four pointing forward to two reversed backward. Mousebirds perch, climb, crawl, and scramble agilely in bushes and trees. They are largely vegetarian but eat some insects. They are nonmigratory and gregarious, living in flocks and sleeping in clusters, but they are monogamous in loose colonies as breeders. The nest is an open cup in a tree or bush, and the two to four young remain in the nest, cared for by both adults until they can fly. The relationships of the mousebirds to other birds are obscure. Mousebirds have a surprisingly good fossil record from the Miocene of France and Germany, suggesting a wider distribution of this group.
Industry:Science
A small order of birds that contains a single family, the Opisthocomidae. Its one species, the hoatzin, is restricted to South America and has been frequently included in the Galliformes as a suborder; however, little evidence supports this conclusion. More recently, some researchers claimed that it was a typical member of the Cuculidae, the cuckoos, based only on evidence from deoxyribonucleic acid (DNA) hybridization studies. However, important differences in the morphology of the perching foot argue strongly against the inclusion of the hoatzin in Cuculidae. The hoatzin has an anisodactyl perching foot with three anterior toes and a well-developed hallux (first toe) that is completely different from the zygodactyl perching foot of the cuckoos (with the second and third toes anterior, and the fourth toe and hallux posterior). Selective demands for perching could not have resulted in the evolution of the anisodactyl foot of the hoatzin from the zygodactyl foot of the cuckoos. In the absence of definite evidence of its relationship to other avian orders, the Opisthocomiformes are best considered as a distinct order that evolved in South America since its isolation from the rest of Gondwanaland sometime in the late Mesozoic.
Industry:Science
