- 行业: Printing & publishing
- Number of terms: 178089
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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.
The determination of a gas pressure that is less in magnitude than the pressure of the atmosphere. This low pressure can be expressed in terms of the height in millimeters of a column of mercury which the given pressure (vacuum) will support, referenced to zero pressure. The height of the column of mercury which the pressure will support may also be expressed in micrometers. The unit most commonly used is the torr, equal to 1 mm (0.03937 in.) of mercury (mmHg). Less common units of measurement are fractions of an atmosphere and direct measure of force per unit area. The unit of pressure in the International System (SI) is the pascal (Pa), equal to 1 newton per square meter (1 torr = 133.322 Pa).
Industry:Science
The different notations used to communicate algorithms to a computer. A computer executes a sequence of instructions (a program) in order to perform some task. In spite of much written about computers being electronic brains or having artificial intelligence, it is still necessary for humans to convey this sequence of instructions to the computer before the computer can perform the task. The set of instructions and the order in which they have to be performed is known as an algorithm. The result of expressing the algorithm in a programming language is called a program. The process of writing the algorithm using a programming language is called programming, and the person doing this is the programmer.
Industry:Science
The electrical transport properties of solids are strongly affected by disorder caused by the presence of impurities or imperfections in the crystal lattice. In 1958, in an article titled “Absence of diffusion in certain random lattices,” P. W. Anderson demonstrated that disorder can spatially localize the electron charge carriers; that is, they become unable to carry an electric current because of their quantum-mechanical wave character. He simultaneously formulated the problem of electron localization in a disordered metal, made the link between localization and electrical transport, and gave the first quantitative estimate of the critical disorder for the disorder-driven metal-insulator transition.
Industry:Science
The central region of an atom. Atoms are composed of negatively charged electrons, positively charged protons, and electrically neutral neutrons. The protons and neutrons (collectively known as nucleons) are located in a small central region known as the nucleus. The electrons move in orbits which are large in comparison with the dimensions of the nucleus itself. Protons and neutrons possess approximately equal masses, each roughly 1840 times that of an electron. The number of nucleons in a nucleus is given by the mass number <i>A</i> and the number of protons by the atomic number <i>Z</i>. Nuclear radii <i>r</i> are given approximately by <i>r</i> = 1.2 × 10<sup>-15</sup> m <i>A</i><sup>1/3</sup>.
Industry:Science
The discovery, development, and application of sustainable chemical reactions that create no waste or generate only benign wastes. The idea that toxic chemicals, once created, can be contained or prevented from entering the environment is unrealistic. Since some portion of the toxins will always enter the environment, whether through use, processing, disposal, or unforeseen circumstances such as accidents, terrorism, or natural disasters, green chemistry solutions are applied at the molecular level to avoid creating toxins in the first place. Using green chemistry to prevent pollution provides a more efficient approach to preserving human health and the environment than waste processing or remediation.
Industry:Science
The general circulation of the ocean. The term is usually understood to include large-scale, nearly steady features, such as the Gulf Stream, as well as current systems that change seasonally but are persistent from one year to the next, such as the Davidson Current, off the northwestern United States coast and the equatorial currents in the Indian Ocean. A great number of energetic motions have periods of a month or two and horizontal scales of a few hundred kilometers—a very low-frequency turbulence, collectively called eddies. Energetic motions are also concentrated near the local inertial period (24 h, at 30° latitude) and at the periods associated with tides (primarily diurnal and semidiurnal).
Industry:Science
Structural abnormalities of the body that develop during embryogenesis and the fetal period; also called birth defects. Children with significant birth defects need more medical care than other children do, require more frequent hospitalizations, need community support services, and often require special education programs. Among children, over half of all visits to subspecialty medical clinics and admissions to hospitals are for treatment of disorders resulting from errors in embryonic development, chromosomal abnormalities, and genetic and familial disorders. Two-thirds of the deaths of infants and children in pediatric hospitals in developed countries are caused by underlying congenital anomalies.
Industry:Science
The human lineage is unique in the animal world for having an adaptation that is based upon the complex use of tools and technology. The archeological record bears testament to the origins and development of technology through time in tandem with major changes in biological evolution. By definition, the archeological record starts as soon as we can identify intentionally or unintentionally modified materials (artifacts) made by humans or protohumans (early hominids) in the prehistoric record. Over the last century and a half, the dates for the origins of the earliest stone tools have been pushed further and further back, as fieldwork intensified in the Old World and dating techniques became more refined.
Industry:Science
The application to biological systems of the theory of encoding effects on signal transmission and communications efficiency. In everyday language, information is associated with knowledge, meaning (semantics), and the influence of information on behavior (pragmatics). Information theory considers information to be quantitative and capable of being expressed in binary digits, or bits. The measure of information is based on its structure or its representation, taking into account the statistical properties of its structure. Mathematical information theory was created to describe the transmission of information in telecommunications, but it has been widely applied also in mathematics, physics, and biology.
Industry:Science
The establishment of the temporal sequence of prehistoric events. During the nineteenth and early twentieth centuries archeologists devised a number of methods to construct a relative chronology for cultural remains. These included stratigraphy (correlation of layered sediments and rocks), seriation (ordering of materials based on changes in style), and cross-dating (using temporally diagnostic ceramic and stone tool types). Beginning in the early twentieth century, dating methods developed in the natural sciences began to be applied to archeological remains to provide absolute (that is, calendar) dates. These are sometimes called chronometric dating methods, and the more commonly used ones are described here.
Industry:Science
