- 行业: Printing & publishing
- Number of terms: 178089
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- Company Profile:
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.
Any one of the crystalline metal aluminosilicates belonging to a class of minerals known as zeolites. These minerals are found widely scattered in nature in relatively small quantities. Synthetic forms of the naturally occurring minerals, as well as many species having no known natural counterpart, have been prepared by a hydrothermal process. An important characteristic of the zeolites is their ability to undergo dehydration with little or no change in crystal structure. The dehydrated crystals are honeycombed with regularly spaced cavities interlaced by channels of molecular dimensions which offer a very high surface area for the adsorption of foreign molecules.
Industry:Science
For many years, scientists have imagined schemes for creating molecular electronic devices. In most instances, the intended capability of the molecular structure has been to switch an electron current on and off. Molecular building blocks, if linked together to form logic functions (AND, OR, NAND, and so on), would seem to lead to a computer of ultimate miniaturization. A simple estimate suggests it might be possible to make molecular-based computers about 1000 times smaller than silicon-based computers. Some key steps have recently been made toward achieving this goal. However, it is not yet known whether the molecular electronics scenario is ultimately reasonable.
Industry:Science
By definition, gambling is the process of placing something of value (usually money) at risk in the hope of gaining something of greater value. Excessive forms of gambling have been described as compulsive, problematic, or pathological, among other terms. Pathological gambling (PG) is the diagnostic term adopted by the American Psychiatric Association. Along with kleptomania, pyromania, intermittent explosive disorder (aggressive outbursts that can be violent or destructive and that are out of proportion to any possible provocation or stimulus), and trichotillomania (compulsive hair pulling), PG is classified as an “Impulse control disorder not elsewhere classified.”
Industry:Science
High blood pressure. The prevalence of this clinical disease in acculturated societies is sufficiently high to warrant its being referred to as a public health problem. Blood pressure is expressed in two numbers: the higher number is the systolic blood pressure, which is the pressure exerted by the blood against the walls of the blood vessels while the heart is contracting. The lower number is the diastolic blood pressure, which is the residual pressure that exists between heart contractions, or while the heart is relaxing. Normal blood pressure provides sufficient blood flow to the vital organs, including the brain, heart, kidneys, intestine, and skeletal muscle.
Industry:Science
Hypothetical objects with masses exceeding 60 solar masses, the mass of the largest known ordinary stars (1 solar mass equals 4.4 × 10<sup>30</sup> lbm or 2 × 10<sup>30</sup> kg). The term is most often used in connection with objects larger than 10<sup>4</sup> solar masses that might be the energy source in quasars and active galaxies. These objects not only are hypothetical but probably do not exist. However, their nonexistence is one of the major assumptions that makes the case for giant black holes, rather than supermassive stars, being the central engines of quasars. The description of supermassive stars presented here is based entirely on theoretical calculations.
Industry:Science
Capillary electrochromatography (CEC) is a separation technique that shares attributes of liquid chromatography and capillary zone electrophoresis. Currently developmental, it has promise for use in separations of multicomponent mixtures in complex matrices such as soils, ground and surface waters, food products, and biological samples. Like capillary zone electrophoresis (CZE), capillary electrochromatography is an efficient technique—that is, it produces a high number of theoretical plates per separation. Like high-performance liquid chromatography (HPLC), capillary electrochromatography is highly selective—it enables differential retention of one analyte over another.
Industry:Science
Cryptochrome is a blue/ultraviolet-A (UV-A) light receptor found in a wide range of organisms from bateria to humans. It was so named because the early studies of cryptochromes were largely done in cryptogamic (flowerless) plants, and because its molecular nature once remained cryptic. Cryptochromes are the only type of photoreceptor known to function in both the plant and animal kingdoms, mediating the influence of light on plant development and the biological clock in plants and animals. Cryptochromes are flavoproteins that share structural similarities with the photoactive deoxyribonucleic acid (DNA)–repairing enzyme DNA photolyase, but do not have photolyase activity.
Industry:Science
Conducting polymers have received much attention since the early 1980s. They have inherent electrical conductivity and are different from other polymeric materials, which are made conducting by blending polymers with carbon or metal powders. In particular, the demonstration that films of conducting polymers on electrodes can be switched electrochemically between the insulating and conductive state with a corresponding change in the electrical, optical, and chemical properties attracted the attention of investigators from various disciplines. The brief overview below presents selected examples to describe the structural characteristics and properties of conducting polymers.
Industry:Science
Earthquake early warning (EEW) is notification of an earthquake's occurrence in real time, that is, after the earthquake has begun. EEW was first successfully implemented in the UrEDAS (Urgent Earthquake Detection and Alarm System) system for Japan Railways in the 1980s. EEW has safely stopped high-speed trains in Japan and provided warnings in Mexico City. More recently, research has identified characteristics of the seismic P wave that permit warning from a single on-site detector. A fully functional EEW system requires not only seismological detectors and processing, but also decision-making and communications apparatus designed in accordance with social science findings.
Industry:Science
Geologic mapping is a highly interpretive, scientific process that can produce a range of map products for many different uses, including assessing ground-water quality and contamination risks; predicting earthquake, volcano, and landslide hazards; characterizing energy and mineral resources and their extraction costs; waste repository siting; land management and land-use planning; and general education. The value of geologic map information in public and private decision-making (such as for the siting of landfills and highways) has repeatedly been described anectodally, and has been demonstrated in benefit-cost analyses to reduce uncertainty and, by extension, potential costs.
Industry:Science
