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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 Arctic treeline is the biogeographic boundary between the boreal forest to the south, dominated by coniferous trees, and tundra vegetation to the north, dominated by small shrubs, herbaceous plants, nonvascular plants, and bare ground. The treeline stretches across North America from northern Alaska to the coast of Labrador, and across Eurasia from Scandinavia to the far east of Siberia. The geographic location of the arctic treeline zone is controlled by global climate patterns but also can influence global climate. For this reason, scientists study past changes in the Arctic treeline to understand the natural variability of climate, detect long-term changes in climate, and predict how future climate changes might affect the treeline.
Industry:Science
The bending of light, or other waves, into the region of the geometrical shadow of an obstacle. More exactly, diffraction refers to any redistribution in space of the intensity of waves that results from the presence of an object that causes variations of either the amplitude or phase of the waves. Most diffraction gratings cause a periodic modulation of the phase across the wavefront rather than a modulation of the amplitude. Although diffraction is an effect exhibited by all types of wave motion, this article will deal only with electromagnetic waves, especially those of visible light. Some important differences that occur with microwaves will also be mentioned. For discussion of the phenomenon as encountered in other types of waves
Industry:Science
The division of biological science concerned with the native or acquired response of complex living organisms to the intrusion of other organisms or foreign substances. The immune system allows the host organism to distinguish between self and nonself and to respond to a target (termed an antigen). An immunological response is specific and can be genetically determined or learned, that is, developed as a consequence of exposure. Examples of immune responses are neutralization of toxic protein molecules, killing of infecting microorganisms, rejection of foreign tissue grafts, and memory by the protective effects of vaccination. The last, discovered by E. Jenner toward the end of the eighteenth century, was the primary immunological finding.
Industry:Science
The fauna and flora of Madagascar, Africa's Great Red Island, can be described as fitting what botanist Quentin C. B. Cronk recently called the “diversity and stability paradox” of island biogeography. The diversity paradox is that, despite the existence of numerous unique island taxa (whose loss would drastically impact the taxonomic diversity of represented groups), the actual species diversity (or richness) of island biota is typically low in comparison with that of like-sized continental landmasses. The stability paradox is that, although island flora and fauna may appear to be stable (as many of the taxa are ancient in origin), they are highly susceptible to rapid change and decimation, particularly when subjected to human colonization.
Industry:Science
The cell wall is the layer of material secreted by the plant cell outside its plasma membrane. All plants have cell walls that are generally very similar in chemical composition, organization, and development. The walls of the Chlorophyta (green algae) show characteristics virtually identical to those of flowering plants, another indication that flowering plants are derived evolutionarily from this division of algae. The wall serves as the first point of entry of materials into cells, functions in the movement of water throughout the plant, and is one of the major mechanical strengthening factors. In addition, the wall must be sufficiently flexible and plastic to withstand mechanical stresses while still permitting the growth of the cell.
Industry:Science
The Cigar Lake deposit, in northern Saskatchewan, Canada, 660 km (410 mi) north of Saskatoon, contains approximately 350 million pounds (160 million kilograms) of triuranium octoxide (U<sub>3</sub>O<sub>8</sub>) reserves, with ore grades of about 20%. It is the second largest and richest uranium orebody in the world. A project was recently undertaken at Cigar Lake to develop an innovative nonentry method for mining and handling high-grade uranium ore. The process commenced at the proof-of-concept stage and ended with a full-scale industrial test. As a result, the jet-boring mining method will be used to extract the ore for the future Cigar Lake operation. The Cigar Lake project is now in the construction phase and could be operational in 2007.
Industry:Science
The increase in electrical conductivity caused by the excitation of additional free charge carriers by light of sufficiently high energy in semiconductors and insulators. Effectively a radiation-controlled electrical resistance, a photoconductor can be used for a variety of light- and particle-detection applications, as well as a light-controlled switch. Other major applications in which photoconductivity plays a central role are television cameras (vidicons), normal silver halide emulsion photography, and the very large field of electrophotographic reproduction. The phenomena related to photoconductivity have also played a large part in the understanding of electronic behavior and crystalline imperfections in a variety of different materials.
Industry:Science
The development of computational algorithms for the identification or extraction of structure from data. This is done in order to help reduce, model, understand, or analyze the data. Tasks supported by data mining include prediction, segmentation, dependency modeling, summarization, and change and deviation detection. Database systems have brought digital data capture and storage to the mainstream of data processing, leading to the creation of large data warehouses. These are databases whose primary purpose is to gain access to data for analysis and decision support. Traditional manual data analysis and exploration requires highly trained data analysts and is ineffective for high dimensionality (large numbers of variables) and massive data sets.
Industry:Science
The hereditary factors of behavior may be studied in animals and humans. Charles Darwin, who originated the theory that natural selection is the basis of biological evolution, was persuaded by Francis Galton that the principles of natural selection applied to behavior as well as physical characteristics. Members of a species vary in the expression of certain behaviors because of variations in their genes, and these behaviors have survival value in some environments. One example of such a behavior is curiosity—some organisms are more curious than others, and in some settings curiosity is advantageous for survival. Therefore, in those environments more of the organisms that express curiosity survive to reproduce than do those that lack this trait.
Industry:Science
The graphic portrayal of spatial distributions of vegetation, ecosystems, or their characteristics. Vegetation is one of the most conspicuous and characteristic features of the landscape and has long been a convenient way to distinguish different regions. Because vegetation provides the basic framework of terrestrial ecosystems, maps of ecosystems and biomes have been mainly vegetation maps. Resources generally must be inventoried and mapped before they can be well managed. Thus, as pressure on the Earth's natural resources grows and as natural ecosystems are increasingly disturbed, degraded, and in some cases replaced completely, the mapping of vegetation and ecosystems, at all scales and by various methods, has become more common and important.
Industry:Science
