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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 major body division of the vertebrate trunk lying posterior to the thorax; and in mammals, bounded anteriorly by the diaphragm and extending to the pelvis. The diaphragm, found only in mammals, separates the abdominal or peritoneal cavity from the pleural and pericardial cavities of the thorax. In all pulmonate vertebrates (possessing lungs or lunglike organs) other than mammals, the lungs lie in the same cavity with the abdominal viscera, and this cavity is known as the pleuroperitoneal cavity.
Industry:Science
A major community of plants and animals having similar life forms or morphological features and existing under similar environmental conditions. The biome, which may be used at the scale of entire continents, is the largest useful biological community unit. In Europe the equivalent term for biome is major life zone, and throughout the world, if only plants are considered, the term used is formation.
Industry:Science
A major constituent (10–47% dry weight) of the cell walls of brown algae. Extracted for its suspending, emulsifying, and gelling properties, it is one of three algal polysaccharides of major economic importance, the others being agar and carrageenan.
Industry:Science
A major constituent of the cell walls of certain red algae, especially members of the families Gelidiaceae and Gracilariaceae. Extracted for its gelling properties, it is one of three algal polysaccharides of major economic importance, the others being alginate and carrageenan.
Industry:Science
A major division of geologic time spanning from 2500 to 543 million years before present (Ma). The beginning of Proterozoic time is an arbitrary boundary that roughly coincides with the transition from a tectonic style dominated by extensive recycling of the Earth's continental crust to a style characterized by preservation of the crust as stable continental platforms. The end of the Proterozoic coincides with the Precambrian-Cambrian boundary, which is formally defined on the basis of the first appearance of diverse coelomate invertebrate animals. Proterozoic Earth history testifies to several remarkable biogeochemical events, including the formation and dispersal of the first supercontinent, the maturation of life and evolution of animals, the rise of atmospheric oxygen, and the decline of oceanic carbonate saturation (see <b>table</b>). Tremendous iron and lead-zinc mineral deposits occur in Proterozoic rocks, as do the first preserved accumulations of oil and gas.
Industry:Science
A major division of late Paleozoic time, considered either as an independent period or as the younger subperiod of the Carboniferous. In North America, the Pennsylvanian has been widely recognized as a geologic period and derives its name from a thick succession of mostly nonmarine, coal-bearing strata in Pennsylvania. Radiometric ages place the beginning of the period at approximately 320 million years ago and its end at about 290 million years ago. In northwestern Europe, strata of nearly equivalent age are commonly designated as Upper Carboniferous and in eastern Europe as Middle and Upper Carboniferous.
Industry:Science
A major division of the animal kingdom comprising all forms with a bilaterally symmetrical body plan (that is, their left and right sides are mirror images, or nearly so) and organ systems that develop from three tissue layers. The animal kingdom, Metazoa, is subdivided into about 30 major animal groups, or phyla, each constructed on a different architectural plan. Most of these phyla are grouped as the Bilateria, comprising a major early branch on the family tree of animals that may have originated nearly 600 million years ago. All bilaterians possess some features that are not perfectly symmetrical (for example, the human heart and liver), but all have descended from an essentially bilateral ancestor. The nonbilaterian phyla include sponges (which lack muscles and nerves), jellyfish, and sea anemones and their allies, which have quasiradial symmetry and organ systems that develop from only two tissue layers (see <b>illustration</b>).
Industry:Science
A major division of the animal kingdom comprising the phyla Hemichordata, Echinodermata, and Chordata. Hemichordata consists of acorn worms (Enteropneusta) and a group of small-bodied, tentaculate forms (Pterobranchia). Echinodermata contains the starfish, sea urchins, crinoids (sea lilies), and their allies. The phylum Chordata includes the Urochordata (sea squirts and larvaceans), Cephalochordata (<i>Branchiostoma</i>, the sand lancelet, formerly <i>Amphioxus</i>), and vertebrates (see <b>illustration</b>). At one time, up to 10 phyla were included in Deuterostomia on the basis of shared morphological and developmental features; however, comparison of deoxyribonucleic acid (DNA) sequences indicates that most of those phyla are more closely allied to other groups.
Industry:Science
A major division of time in geologic history, extending from about 540 to 250 million years ago (Ma). It is the earliest era in which significant numbers of shelly fossils are found, and Paleozoic strata were among the first to be studied in detail for their biostratigraphic significance. Western Europe, especially the British Isles, was the cradle of historical geology. Early work with rock strata and their fossils was strictly practical; the relative ages of rock units were essential for correlating scattered outcrops to search for natural resources—particularly coal—in the early part of the nineteenth century.
Industry:Science
A major division within the animal kingdom containing the majority of animal species and comprising the phyla Priapulida, Kinorhyncha, and Loricifera (no common names), Arthropoda (insects, crustaceans, spiders, etc.), Onychophora (velvet worms), Tardigrada (water bears), and Nematoda (roundworms). These forms include animals with disparate morphologies, but their close relationship is suggested by molecular DNA sequence comparisons—especially of both large and small subunit RNA molecules—and is consistent with myosin heavy-chain sequence comparisons and with a variety of uniquely shared genomic and morphological features. Ecdysozoans were named after their habit of molting (ecdysis), unique among invertebrates, and presumably all are descended from a common molting ancestor.
Industry:Science
