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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 geographic boundary or transition zone between two different groups of plant or animal distributions. The term has been used to denote transitions at different spatial scales or levels of analysis, and may refer to any one of several attributes of the organisms involved. For example, an ecotone could refer to physiognomy (roughly, the morphology or appearance of the relevant organisms), such as between the boreal forest and grassland biomes; or it could refer to composition, such as between oak-hickory and maple-basswood forest associations; or it could refer to both. Ecotones are generally distinguished from other geographic transitions of biota by their relative sharpness. The ecotone between boreal forest and prairie in central Saskatchewan occurs over a hundred kilometers or so, in contrast to the transition from tropical forest to savanna in South America or Africa that is associated with increasing aridity and is dispersed over hundreds of kilometers. The “tension zone” between broadleaf deciduous forests in south-cental Michigan and mixed forests to the north is similarly sharp. Ecotones are thought to reflect concentrated long-term gradients of one or more current environmental (rather than historical or human) factors. Though often climatic, these factors can also be due to substrate materials, such as glacial sediments or soils. Regardless of their specific environmental basis, most ecotones are thought to be relatively stable.
Industry:Science
A geographic designation that includes thousands of mainly small coral and volcanic islands scattered across the Pacific Ocean from Palau in the west to Easter Island in the east (see <b>illus.</b>). Island archipelagos off the coast of the Asian mainland, such as Japan, Philippines, and Indonesia, are not included even though they are located within the Pacific Basin. The large island constituting the mainland of Papua New Guinea and Irian Jaya is also excluded, along with the continent of Australia and the islands that make up Aotearoa or New Zealand. The latter, together with the Asian Pacific archipelagos, contain much larger landmasses, with a greater diversity of resources and ecosystems, than the oceanic islands, commonly labelled Melanesia, Micronesia, and Polynesia (see illus.).
Industry:Science
A geometric figure consisting of an ordered set of three or more (but a finite number of) points called vertices, each vertex connected by line segments called sides or edges to two other vertices. These two sides are said to be adjacent, and so are any two vertices that are end points of a side. The perimeter of the polygon is the sum of the lengths of the sides. The line segments that join two nonadjacent vertices of a polygon are called diagonals. A polygon is said to be directed, or oriented, if a preferred direction is assigned to each side so that at each vertex one of the adjacent sides is directed toward the vertex and the other away from it.
Industry:Science
A geometry that investigates those properties of figures that are unchanged (invariant) when the figures are projected from a point to a line or plane. Although isolated theorems appeared earlier, the first systematic treatment of the subject was given by the French army officer. J. V. Poncelet (1788–1867), who began his <i>Traité des propriétés projectives des figures</i> in 1812 while a prisoner of war in Russia.
Industry:Science
A gland which produces and liberates sebum, a mixture composed of fat, cellular debris, and keratin. When the gland arises in association with a hair follicle, it forms a thickened outpushing from the side of the developing follicle near the epidermis. Central cells in these sebaceous glands form oil droplets within the cytoplasm. These cells disintegrate to liberate the sebaceous substance and are therefore of the holocrine type. The Meibomian or tarsal glands, within the tarsus or supporting plate at the edge of the eyelids, are sebaceous and complex tubuloacinous structures. The numerous separate glands open along the entire edge of the upper and lower lids. Retained secretions of the tarsal glands produce a cyst termed a chalozion or Meibomian cyst.
Industry:Science
A glassy, solid-state device used to control the flow of electric current. Useful solid-state devices can be made from glassy as well as crystalline semiconductors. Crystals possess long-range order; that is, given the position of any particular atoms and the orientation of the neighboring atoms, the location of any other atom is known, no matter how far away from the atom under consideration. A glass is a special case of a noncrystalline class of materials, namely, amorphous solids. These do not exhibit long-range order, although they tend to have the same local structure (that is, short-range order) as the corresponding crystal. A glass is an amorphous solid that is formed by cooling rapidly from the liquid phase.
Industry:Science
A global ban on the explosive testing of nuclear devices is the motivation behind the Comprehensive Test Ban Treaty. The treaty is viewed by its advocates as a means to avoid nuclear warfare and to lessen international tensions generally. Practically speaking, it is assumed that any nation with access to plutonium can fabricate, without explosive testing, a nuclear weapon like that dropped on Nagasaki by the United States in 1945. A ban on explosive testing deters an emerging nuclear state from developing more sophisticated weapons that employ plutonium fission or thermonuclear fusion or that are sufficiently compact to deliver on a missile. For countries with nuclear arms, a ban on testing does not render their weapon stockpiles ineffective. Rather, the ban is intended to deter them from modernizing weapon design. The test ban treaty is only one tool available to the international community to deter the proliferation of nuclear weapons. Export controls on fissile materials and nuclear technology, safeguards for weapon stockpiles, and regulations on plutonium disposal from nuclear power plants are also necessary.
Industry:Science
A glycoprotein that is normally present in significant amounts only in the serum of the fetus. It is produced in the yolk sac, the liver, and other tissues of the gastrointestinal tract. Its role is unknown, but alpha fetoprotein may function as a carrier (or modulator of the concentration) of a small ligand, as an immunosuppressive, as a modulator of intracellular transport of unsaturated fatty acids, as a factor in estrogen transport, or as a means of binding retinoic acid.
Industry:Science
A graphic device that depicts tasks, machines, personnel, or whatever resources are required to accomplish a job on a calendar-oriented grid. Charts may be provided for various managerial levels and responsibilities, but detailed planning occurs at the lowest organizational level. Performance may be monitored and controlled throughout the organization.
Industry:Science
A graphical display depicting complex nonlinear relationships in electronic circuits. A typical use is to show voltage-current relationships in semiconductor devices. Device amplification capabilities, for example, are exhibited by a characteristic plot which traces output current versus output voltage with a third controlling variable as a parameter. This control variable could be the base current of a bipolar junction transistor (BJT) or the gate-to-source voltage of a metal-oxide-semiconductor (MOS) transistor.
Industry:Science
