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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.
Any colored, organic compound, usually called dye, used to stain tissues, cells, cell components, or cell contents. The dye may be natural or synthetic. The object stained is called the substrate. The small size and transparency of microorganisms make them difficult to see even with the aid of a high-power microscope. Staining facilitates the observation of a substrate by introducing differences in optical density or in light absorption between the substrate and its surround or between different parts of the same substrate. In electron microscopy, and sometimes in light microscopy (as in the silver impregnation technique of staining flagella or capsules), staining is accomplished by depositing on the substrate ultraphotoscopic particles of a metal such as chromium or gold (the so-called shadowing process); or staining is done by treating the substrate with solutions of metallic compounds such as uranyl acetate or phosphotungstic acid. This type of staining is not dealt with in this article.
Industry:Science
Any of a number of procedures for the fitting of a selected geometric model to a body of multivariate data. In the original form advanced by Warren S. Torgerson, multidimensional scaling dealt with judgments about stimuli, with its major aim being the derivation of psychological dimensions presumed to underlie the judgments, and the determination of scale values for stimuli along the derived dimensions. Classical multidimensional scaling was a significant methodological advance in the characterization of complex stimulus domains. If forced to rely exclusively on unidimensional scaling methods, a researcher could characterize a multidimensional stimulus domain only by first scaling the stimuli on individual dimensions and later assembling the scaled dimensions in a postulated model. Even then, the model would often be incomplete because of insufficient foresight in choice of dimensions, or inability to determine the relations between, and relative importance of, the chosen constituent dimensions.
Industry:Science
Chemical sensors are used in a large variety of applications where manual chemical analysis is at a disadvantage. Chemical analysis may be difficult to perform, for example, because the sample is too small, because the measurement results are needed immediately to close a feedback loop, or because the measurements have to be performed in remote locations. One way to construct a chemical sensor is by measurement of a material property that reversibly changes upon exposure to the chemical species of interest. The property must be easily measurable (in practice, only optical and electrical material properties seem to meet this criterion), and it must change considerably when the material is exposed to the target species, but it must not depend on exposure to any other species or on temperature (that is, it must not be cross-sensitive). Practical sensors meet only a relevant subset of these criteria; that is, they can be used over only a certain range of temperatures or in a certain concentration range.
Industry:Science
Flow of gases in which heat exchanges produce a significant effect on the flow. Traditionally, aerodynamics treats the flow of gases, usually air, in which the thermodynamic state is not far different from standard atmospheric conditions at sea level. In such a case the pressure, temperature, and density are related by the simple equation of state for a perfect gas; and the rest of the gas's properties, such as specific heat, viscosity, and thermal conductivity, are assumed constant. Because fluid properties of a gas depend upon its temperature and composition, analysis of flow systems in which temperatures are high or in which the composition of the gas varies (as it does at high velocities) requires simultaneous examination of thermal and dynamic phenomena. For instance, at hypersonic flight speed the characteristic temperature in the shock layer of a blunted body or in the boundary layer of a slender body is proportional to the square of the Mach number. These are aerothermodynamic phenomena.
Industry:Science
Herbicides are chemicals that kill plants, and selective herbicides are those that can kill certain plant species (weeds) while not injuring other plant species (crops). Since the introduction and commercialization of synthetic organic herbicides in the late 1940s, farmers have been increasingly reliant on herbicides for weed control. This is particularly true for agriculture in many developed countries, where there has also been a shift toward increased mechanization with larger machines and reduced tillage (less cultivation of the soil between plantings). Although herbicides have been widely used for only the past 60 years, societal changes have occurred in developed countries that would make it very difficult to return to previous weed control practices. These societal changes include a shift to fewer but larger farms with the simultaneous depopulation of rural areas, shortages of farm labor, and an increasing average wage paid to farm workers, which makes handweeding uneconomic in many instances.
Industry:Science
Glycoproteins, that is, proteins with covalently attached sugars, are important in a myriad of biological processes and materials, including the determination of blood type, the resilience of cartilage, and virus infection. Glycoproteins may remain within the cells in which they are produced, attach to the cell surface, or be secreted. They have a diverse range of functions, including intercellular recognition, modulation of biological activity, and alteration of protein stability. The understanding of glycoproteins has lagged behind the study of other biomolecules such as DNA and RNA due to difficulties in working with glycoproteins. Biological systems produce glycoproteins as heterogeneous mixtures, and this presents practical problems in the purification of glycoproteins and the characterization of their biological effects. Currently, much research is focused on developing methods for glycoprotein synthesis that would offer access to homogeneous glycoproteins for biological and biophysical studies.
Industry:Science
Assembling the universal Tree of Life is an ambitious project that intends to provide a framework for what scientists interpret as the genealogy of life on planet Earth. The branch of biology involved in this tree-building processs is called phylogenetics, and it combines efforts from all areas of organismal biology together with mathematics and computer science. Phylogeneticists reconstruct phylogenetic trees (hypothetical genealogies of organisms) which are primarily derived from analyses of morphological, anatomical, physiological, developmental, behavioral, and molecular attributes assembled in data matrices. Molecular attributes include primarily deoxyribonucleic acid (DNA) and ribonucleic acid (RNA) sequence data, but also include the structure of proteins or genomes. Although molecular sequence data are at the forefront of assembling the Tree of Life, more traditional morphological data are still important, especially for fossils and extinct or rare species, as these are the only data available.
Industry:Science
Construction of the physical components of the telephone system from the central office to the end user. The telephone system can be roughly divided into three major components: outside plant, switching equipment, and interoffice facilities. The outside plant can be thought of as the local cables that bring the phone service to the subscribers' premises. The switching equipment resides in a building called a central office and serves to route the call to the correct location. The interoffice facilities connect one central office to another. When a call is initiated, the outside plant carries the signal to the local central office. The switching equipment in the local central office then determines the location to which the call needs to be routed. The call is then routed over the interoffice facilities to the central office serving the person being called, where the switching equipment then connects the call to the local outside plant. This article describes the outside plant portion of the telephone system.
Industry:Science
Everyone experiences, at least on occasion, feelings of anxiety—for example, pangs of dread before giving a public speech, worries about relationships or success at work, or a swelling sensation of fear when walking down a dimly lit street. These common experiences, however, are qualitatively different from clinical anxiety disorders, which are more than just exaggerated manifestations of these common experiences. Rather, individuals with anxiety disorders are burdened frequently by invasive thoughts and overwhelming emotions that can come on without warning, cause severe personal distress, and interfere with an individual's day-to-day functioning and personal relationships. As many as 40 million adults in the United States suffer from clinical anxiety disorders, which fall primarily into six diagnostic categories: panic disorder (PD), generalized anxiety disorder (GAD), social phobia or social anxiety disorder (SAD), specific phobia, posttraumatic stress disorder (PTSD), and obsessive-compulsive disorder (OCD).
Industry:Science
Chromosome painting in its original sense (as applied to humans and other animals) is defined as the use of fluorescently labeled, chromosome-specific probes to visualize whole chromosomes or large-scale chromosome regions. Such probes are obtained from chromosomes or chromosome segments isolated either by flow sorting (separation of chromosomes in a suspension on the basis of their relative fluorescence using a flow cytometer/sorter) or microdissection isolation of deoxyribonucleic acid (DNA) from a particular chromosome type or its part using a fine microcapillary pipette. The isolated DNA probes are amplified by polymerase chain reaction (PCR), fluorescently labeled, and visualized on chromosome preparations on a microscopic slide. This technique is commonly known as fluorescence in situ hybridization (FISH), and it refers to the physical mapping of the recombination (hybridization) of fluorescently labeled DNA or ribonucleic acid (RNA) probes with complementary nucleic acid sequences in chromosomes or nuclei.
Industry:Science
