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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 distribution of atmospheric pressure and mass such that the specific volume, or density, of air is a function of both pressure and temperature, but not either alone. When the field is baroclinic, solenoids are present, there is a gradient of air temperature on a surface of constant pressure, and there is a vertical shear of the geostrophic wind. Significant development of cyclonic and anticyclonic wind circulations typically occurs only in strongly baroclinic fields. Fronts represent baroclinic fields which are locally very intense.
Industry:Science
A distribution of atmospheric pressure and mass such that the specific volume, or density, of air is a function solely of pressure. When the field is barotropic, there are no solenoids, air temperature is constant on a surface of constant pressure, and there is no vertical shear of the geostrophic wind. Significant cyclonic and anticyclonic circulations typically do not develop in barotropic fields. Considerable success has been achieved, paradoxically, in prediction of the flow pattern at middle-tropospheric elevations by methods which are strictly applicable only to barotropic fields, despite the fact that the field in this region is definitely not barotropic. The subtropics, however, are to a large extent barotropic.
Industry:Science
A disturbance, produced by the acceleration or oscillation of an electric charge, which has the characteristic time and spatial relations associated with progressive wave motion. A system of electric and magnetic fields moves outward from a region where electric charges are accelerated, such as an oscillating circuit or the target of an x-ray tube. The wide wavelength range over which such waves are observed is shown by the electromagnetic spectrum. The term electric wave, or hertzian wave, is often applied to electromagnetic waves in the radar and radio range. Electromagnetic waves may be confined in tubes, such as wave guides, or guided by transmission lines. They were predicted by J. C. Maxwell in 1864 and verified experimentally by H. Hertz in 1887.
Industry:Science
A diurnal, thermally driven circulation in which a surface convergence zone often exists between airstreams having over-water versus over-land histories. The sea breeze is one of the most frequently occurring small-scale (mesoscale) weather systems. It results from the unequal sensible heat flux of the lower atmosphere over adjacent solar-heated land and water masses. Owing to the large thermal inertia of a water body, during daytime the air temperature changes little over the water while over land the air mass warms. Occurring during periods of fair skies and generally weak large-scale winds, the sea breeze is recognizable by a wind shift to onshore, generally several hours after sunrise. On many tropical coastlines the sea breeze is an almost daily occurrence. It also occurs with regularity during the warm season along midlatitude coastlines and even occasionally on Arctic shores. Especially during periods of very light winds, similar though sometimes weaker wind systems occur over the shores of larger lakes and even wide rivers and estuaries (lake breezes, river breezes). At night, colder air from the land often will move offshore as a land breeze. Typically the land breeze circulation is much weaker and shallower than its daytime counterpart.
Industry:Science
A diverse class of extinct, marine, stalked echinoderms whose stratigraphic range extends from the Late Cambrian (505 MA) through Upper Devonian (360 MA). The class is named for rhombus-shaped structures (rhombs) that circulated seawater or body fluids through the body for the respiratory extraction of dissolved oxygen. The main body, or theca, held the visceral mass and was attached to the seafloor by a short to long stem. Atop the theca were variously developed small appendages that were used for suspension feeding in slowly moving currents. This class is composed of three distantly related groups: Glyptocystitida, Hemicosmititida, and Caryocystitida (see <b>illustration</b>). A fourth group, Polycosmititida, is too poorly known to assign to Rhombifera with certainty.
Industry:Science
A diverse group of early jawed fishes from the Paleozoic Era, usually classified as a distinct class of vertebrates. Most acanthodians have tiny body scales with a cross section like that of an onion, the layers reflecting incremental scale growth. Most acanthodians have strong spines at the leading edges of all fins except for the caudal (tail) fin. Acanthodians mostly were small fishes with large mouths and large eyes, suggesting an active, predatory lifestyle feeding on small prey, including other fishes. The oldest well-preserved examples are of Early Silurian age, and the last surviving examples are of Early Permian age. Primitive forms tended to be from marine environments and to have stouter bodies, larger stouter fin spines, and larger numbers of paired spines in front of the pelvic fins. Later forms are found also in freshwater and estuarine habitats and had more slender bodies with fewer and more slender spines.
Industry:Science
A diverse order of land birds found mainly in the tropics. The interrelationships of several families have been disputed, with no resolution. The closest affinities of the coraciiforms may be with other land birds, such as the Piciformes and Passeriformes.
Industry:Science
A diverse phylum of aquatic animals that are characterized by the possession of (1) intrinsic nematocysts, (2) a single body space that opens to the external medium, (3) radial or biradial symmetry, (4) tissue level of organization, and (5) diploblastic structure. With few exceptions, a cnidarian also has tentacles surrounding the mouth (the opening of the body cavity to the exterior). Most definitions of the phylum include the feature metagenesis; however, although the life cycle of many cnidarians involves this alternation between an asexually reproducing polyp and a sexually reproducing medusa, this is not true of two entire classes (Anthozoa and Staurozoa) and of some members of class Hydrozoa. The name Coelenterata, which has been used for this phylum, is being supplanted because, as sometimes used, it included the sponges (Porifera) and comb jellies (Ctenophora), as well as the animals now called cnidarians.
Industry:Science
A diversified group of diapsid reptiles, comprising dinosaurs (and their descendants, birds), crocodylians, pterosaurs (flying reptiles), and various forms closely related to these groups. In the past, the primitive archosaurs from the Triassic Period were collectively referred to as Thecodontia, but this is an artificial grouping that is no longer accepted by specialists.
Industry:Science
A diversified group of materials-handling machines specialized in design and construction for handling unpackaged, divided materials.
Industry:Science
