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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 science of determining the polarization state of electromagnetic radiation (x-rays, light or radio waves). Radiation is said to be linearly polarized when the electric vector oscillates in only one plane. It is circularly polarized when the <i>x</i>-plane component of the electric vector oscillates 90° out of phase with the <i>y</i>-plane component. In experimental work, the polarization state is usually expressed in terms of the Stokes parameters <i>I</i> (the total intensity of the radiation), <i>Q</i> (the preference for light to be linearly polarized in the <i>x</i> plane or at 0° in the instrument reference system), <i>U</i> (the preference for linear polarization at 45°), and <i>V</i> (the preference for left-circular polarization). When <i>Q/I</i> = 1, for example, the radiation is 100% linearly polarized along an axis at 0°. Similarly, <i>V/I</i> = −1 means that the light is 100% right-circularly polarized.
Industry:Science
The presence of microorganisms in food is a natural and unavoidable occurrence. Cooking generally destroys most harmful bacteria, but undercooked foods, processed ready-to-eat foods, and minimally processed foods can contain harmful bacteria that are serious health threats. Meat, dairy, and poultry products are important reservoirs for many of the food-borne pathogens, including <i>Salmonella, Campylobacter, Listeria</i>, and <i>Escherichia coli</i> O157:H7. Animal by-products, such as feed supplements, may also transmit pathogens to food animals (for example, <i>Salmonella</i> and bovine spongiform encephalopathy). Seafood is another potential source of food-borne pathogens, such as <i>Vibrio, Listeria</i>, and Hepatitis A. Infectious doses of many of these pathogens are very low (~10 bacterial cells), increasing the vulnerability of the elderly, infants, and people with immunological deficiencies or organ transplants.
Industry:Science
The outermost of the several extraembryonic membranes in amniotes (reptiles, birds, and mammals) enclosing the embryo and all of its other membranes. The chorion, or serosa, is composed of an outer layer of ectodermal cells and an inner layer of mesodermal cells, collectively the somatopleure. Both layers are continuous with the corresponding tissue of the embryo. The chorion arises in conjunction with the amnion, another membrane that forms the outer limb of the somatopleure which folds up over the embryo in reptiles, birds, and some mammals. The chorion is separated from the amnion and yolk sac by a fluid-filled space, the extraembryonic coelom, or body cavity. In those mammals in which the amnion forms by a process of cavitation in a mass of cells, instead of by folding, the chorion forms directly from the trophoblastic capsule, the extraembryonic ectoderm, which becomes gradually underlain by extraembryonic mesoderm.
Industry:Science
The phylum Rotifera consists largely of free-living animals less than 1 mm long that are common in aquatic ecosystems throughout the world. Although most rotifers have fewer than 1000 cells, they have muscles, ganglia, sensory organs, structures for feeding and swimming, and digestive and secretory organs. Rotifers are characterized by a ciliated head structure, the corona, used for locomotion and food gathering, and a muscular pharynx, the mastax, used to process food. All rotifers have a syncytial epidermis with an intracytoplasmic lamina that is unique among metazoans. Rotifers employ a wide variety of reproductive modes: some species reproduce only sexually, some alternate between sexual and asexual reproduction, and others reproduce only asexually. The successful evolution of asexuality in rotifers renders them important model organisms in studying why sexual reproduction is the dominant form of reproduction in animals.
Industry:Science
The stratosphere is the layer of Earth's atmosphere at altitudes between 8 and 30 mi (13 and 50 km). It is a stable region with few clouds and no storms. While the stratosphere is important for the environment at the Earth's surface (it contains the ozone layer that protects us from harmful ultraviolet radiation), it has been thought to have little influence on weather and climate near the ground. The density of air decreases rapidly with altitude, so in order to conserve their total energy, disturbances must strengthen when they propagate upward through the atmosphere and weaken when they propagate downward. Upward influences, therefore, are stronger than downward ones. While there has been sporadic interest in the idea that winds and temperatures in the stratosphere might influence weather and climate, only in the past few years has this idea found enough observational support to merit serious attention from meteorologists.
Industry:Science
The liver provides a critical interface between body and food. Digestion facilitates absorption of nutrients and other substances into the blood. Unfortunately, some of these substances are potentially toxic and cannot be incorporated into cellular components or excreted from the organism without chemical modification. Blood from the intestine goes to the liver through the hepatic portal vein, carrying with it all absorbed food components. Toxic chemicals might be found in this mix, such as plant alkaloids (for example, mushroom toxins), drugs, or chemicals formed during food processing. Hepatic architecture is based on inflow and outflow of blood from the microanatomical units making up the whole organ, and known as lobules or acini, each about 4–5 mm in diameter. Areas around the points of entry of blood into each lobule are called periportal, whereas areas around the outflow of blood from each lobule are called pericentral.
Industry:Science
The requirement of high salt (NaCl) concentrations for growth of microorganisms. Microorganisms (mainly bacteria) can be classified by their physiological tolerance to salt. Most normal eubacteria, such as <i>Escherichia coli</i> and <i>Pseudomonas fluorescens</i>, and most fresh-water microorganisms, are nonhalophiles (best growth at less than 1.2% NaCl). Slight halophiles (1.2–3% NaCl) include many marine microorganisms. Moderate halophiles (3–15% NaCl) include <i>Vibrio costicola</i>, <i>Paracoccus halodenitrificans</i>, and many others. Borderline extreme halophiles (9–25% NaCl) include the photosynthetic bacterium <i>Ectothiorhodospira halophila</i>, the actinomycete <i>Actinopolyspora halophila</i>, and the halophylic archaebacteria <i>Halobacterium volcanii</i> and <i>H. mediterranei</i>. Extreme halophiles (require at least 10% NaCl; optima 15–30% NaCl) are <i>Halobacterium salinarium</i> and <i>Halococcus morrhuae</i>.
Industry:Science
The process whereby cells interact and attach to other cells or to inanimate surfaces. Cell adhesion is mediated by cell surface proteins and associated macromolecules. It forms the physical basis of multicellularity, morphogenesis and embryonic development, tissue integrity, host–pathogen interactions, immune system function, and the ecological integration of microbial communities. In addition to attaching cells to one another, cell adhesion systems act to coordinate a wide range of cellular behaviors. In animal cells, sites of adhesion serve to organize the system of intracellular protein filaments, known as the cytoskeleton, responsible for cell shape and movement. Adhesive interactions are critical for juxtacrine signaling, by which neighboring cells communicate. Juxtacrine signals regulate gene expression and cell behavior and determine whether a cell survives, divides, differentiates, or undergoes programmed cell death (apoptosis).
Industry:Science
The outermost of the four giant planets. Neptune is a near twin of Uranus in size, mass, and composition. Its discovery in 1846 within a degree from the theoretically predicted position was one of the great achievements of celestial mechanics. Difficulties in accounting for the observed motion of Uranus by means of perturbations by the other known planets led early in the nineteenth century to the suspicion that a new planet, beyond the orbit of Uranus, might be causing the deviation from the predicted path. The difficult problem of deriving the mass and orbital elements of the unknown planet was solved independently in 1845–1846, first by J. C. Adams in Cambridge, England, and then by U. J. Leverrier in Paris. Adams's result did not receive immediate attention, and so it was Leverrier's solution that led to the discovery of Neptune by J. G. Galle, in Berlin, who found the planet on September 23, 1846, only 55′ from its calculated position.
Industry:Science
The serologic reactions of the tissue and blood-cell antigens of most animals are normally characteristic of the species. Significant serologic cross reactions usually occur only with antisera to the corresponding antigens of closely related species. The numerous groups of heterophile antigens—of which the Forssman antigens are the best studied—constitute significant exceptions. Heterophile antigens link the species hog-ox-human (blood group A), cat-horse, and dog-hog-cat-human, while several heterophile groups link otherwise diverse microorganisms. Links between pneumococcus type XIV and the human blood groups are also known, as well as similarities between antigens in mammalian hearts and the cell walls of the group A hemolytic streptococcus—a bacterium that is a common cause of rheumatic fever in humans. The cross reactions between the <i>Proteus</i> bacillus and the <i>Rickettsiae</i> are important in the diagnosis of typhus fever.
Industry:Science
