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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 celestial radio source producing intense short bursts of radio emission. Since their discovery in 1968, over 1750 pulsars have been found (as of October 2006), and it has become clear that 100,000 pulsars must exist in the Milky Way Galaxy—most of them too distant to be detected with existing radio telescopes.
Industry:Science
A cell's genome contains instructions required by that cell to function and exist. All organisms, whether single-celled or multicellular, require a complete set of instructions contained in the form of DNA for each cell to function properly. Thus, a cell faces two challenges: (1) it must replicate its entire genome; and (2) during cell division, it must ensure that each daughter cell receives one copy of the identical sister chromatids (duplicated DNA double helices), which were produced during replication. How the eukaryotic cell orchestrates DNA replication and how it ensures correct segregation of sister chromatids are fundamental questions in cell biology. Importantly, failure to accurately segregate chromosomes during cell division carries severe consequences for daughter cells, including aneuploidy (deviation from a normal chromosome number), which is a condition thought to contribute to the development of cancer. One cellular strategy that is essential for faithful chromosome segregation is sister chromatid cohesion.
Industry:Science
A cellular automaton is a hypothetical computer constructed of a regular array of cells that interact with neighboring cells according to a set of simple rules. Though conceptually simple, cellular automata can produce complex and surprising behavior. To computer scientists and mathematicians, cellular automata are of great interest from a theoretical perspective, forming one of the fundamental abstractions (along with Turing machines, finite-state automata, and so on) that are a basic model for all of computing. They are also an example of evolutionary computation, a set of computing techniques that are based on nature's laws of evolution and are important in the related field of artificial life, which involves interest in virtual (computer-based) life forms. To cellular automata hobbyists, they are a dynamic art form that often produces interesting results.
Industry:Science
A cellular constituent that is one of the building blocks of ribonucleic acids (RNA) and deoxyribonucleic acid (DNA). In biological systems, nucleotides are linked by enzymes in order to make long, chainlike polynucleotides of defined sequence. The order or sequence of the nucleotide units along a polynucleotide chain plays an important role in the storage and transfer of genetic information. Many nucleotides also perform other important functions in biological systems. Some, such as adenosine triphosphate (ATP), serve as energy sources that are used to fuel important biological reactions. Others, such as nicotinamide adenine dinucleotide (NAD) and coenzyme A (CoA), are important cofactors that are needed to complete a variety of enzymatic reactions. Cyclic nucleotides such as cyclic adenosine monophosphate (cAMP) are often used to regulate complex metabolic systems. Chemically modified nucleotides such as fluoro-deoxyridine monophosphate (Fl-dUMP) contain special chemical groups that are useful for inactivating the normal function of important enzymes. These and other such compounds are widely used as drugs and therapeutic agents to treat cancer and a variety of other serious illnesses.
Industry:Science
A centrifuge of high or low speed which provides convection-free conditions and which is used for quantitative measurement of sedimentation velocity or sedimentation equilibrium or for the separation of solutes in liquid solutions.
Industry:Science
A century and a half ago, in <i>On the Origin of Species</i> Charles Darwin presented the notion that animal evolution was governed by natural selection, by which fitness in the face of competition, predation, and environmental vicissitudes determined the continued survival of a species or its extinction. New species evolved when variations in morphology, reproductive success, or behavior led to improved adaptation in the struggle for existence and these new traits were passed on to offspring.
Industry:Science
A cereal grass plant (× <i>Triticosecale</i>) obtained from hybridization of wheat (<i>Triticum</i>) with rye (<i>Secale cereale</i>). It is a crop plant with a small-seeded cereal grain that is used for human food and livestock feed. Worldwide, triticale is slowly gaining importance as a cereal grain. In 1998 it was estimated that about 2.9 million hectares (7.2 million acres) were planted each year. The European continent dominates triticale production with 70% of the total area. Countries with the greatest production (more than 100,000 ha, or 247,000 acres) are Poland, Russia, Germany, France, Australia, Brazil, and the United States.
Industry:Science
A cereal grass plant whose seeds are useful to humans. It is grown in nearly all cultivated areas of the temperate parts of the world, and is an important crop in Europe, North and South America, North Africa, much of Asia, and Australia. Barley is the most dependable cereal crop where drought, summer frost, and alkali soils are encountered. In the United States, barley is grown to some extent in 49 states, with the most important production areas in North Dakota, Montana, and California. Principal uses of barley grain are as livestock feed, for the production of barley malt, and as human food. It is also used in some areas for hay and silage.
Industry:Science
A chamber at the oral end of the vertebrate alimentary canal, leading to the esophagus. Because of divergent specializations in the various classes of vertebrates, it cannot be described in general terms except at embryonic stages. In adult humans it is divided anteriorly by the soft palate into a nasopharynx and an oropharynx, lying behind the tongue but anterior to the epiglottis; there is also a retropharyngeal compartment, posterior to both epiglottis and soft palate. The nasopharynx receives the nasal passages and communicates with the two middle ears through auditory tubes. The retropharynx leads to the esophagus and to the larynx, and the paths of breathing and swallowing cross within it. In adult fishes, the pharynx is not segregated from the mouth cavity but is pierced by a number of paired gill slits.
Industry:Science
A chamber heated to high temperature by electricity. The furnace consists of a refractory shell to resist the high temperatures attained within the chamber and minimize the heat losses to the surrounding area, plus a power source and electrical circuit to provide the heat. The operating temperatures range from a few hundred degrees Celsius to the melting points of refractory metals. The heating mechanism may be resistance, induction, microwave, or an electric arc in the largest installations. Electric furnaces are used primarily in the metallurgical industries for heat-treating, melting, and smelting operations. Resistance furnaces are used for heat treating. Induction furnaces are used to melt relatively low-melting alloys for casting, while arc furnaces are used for melting and smelting applications. The range of furnace powers, sizes, and geometries varies immensely. Powers range from a few kilowatts to 100 megavolt-amperes in a single unit. The furnace volume may be less than a cubic meter to more than 300 m<sup>3</sup>. Both cylindrical and rectangular geometries are common.
Industry:Science
