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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.
Cosmic expansion is speeding up. In 1998, astronomers showed evidence from exploding stars that the expansion of the universe is not slowing down because of the gravity of matter in the universe. By observing the light from distant supernovae, astronomers can measure the distance to each explosion. By studying the redshift in the supernova's spectrum, they can measure the expansion of the universe since the light was emitted and, from a set of these measurements, can trace the history of cosmic expansion. Instead of seeing a slowing universe, as expected, observations indicate there is a component of the universe, called the dark energy, that makes cosmic expansion speed up. Dark energy comprises about two-thirds of the energy density of the universe. While it may be related to Albert Einstein's controversial cosmological constant, its true nature remains to be discovered by observation and thought.
Industry:Science
Atomic and electronic defects of various types in solids which produce optical absorption bands in otherwise transparent crystals such as the alkali halides, alkaline earth fluorides, or metal oxides. They are general phenomena found in a wide range of materials. Color centers are produced by gamma radiation or x-radiation, by addition of impurities or excess constituents, and sometimes through electrolysis. A well-known example is that of the <i>F</i>-center in alkali halides such as sodium chloride (NaCl). The designation <i>F</i>-center comes from the German word <i>Farbe</i>, which means color. <i>F</i>-centers in sodium chloride produce a band of optical absorption toward the blue end of the visible spectrum; thus the colored crystal appears yellow under transmitted light. On the other hand, potassium chloride (KCl) with <i>F</i>-centers appears magenta, and potassium bromide (KBr) appears blue.
Industry:Science
Autonomous underwater vehicles have been designed to make measurements, relay information, or perform tasks in a critical, inhospitable environment. Both large vehicles (transport-class platforms) and small vehicles (network-class platforms) have a role in exploring and working in the ocean. Historically, large vehicles have often been designed to address specific missions. Recently, small vehicles, enabled by advances in technology, are evolving more generically to address measurement of a variety of ocean state variables. Mapping ocean variability today and forecasting it tomorrow requires coupled modeling-sampling systems. In advanced nowcasting/forecasting systems, modeling and sampling are intimately linked by design. Sampling initializes a model which then produces three-dimensional fields used to guide further sampling. The feedback in this adaptive approach is tuned to minimize forecast error.
Industry:Science
Deoxyribonucleic acid is the genetic material which serves as the template or code for cellular processes in living organisms. DNA is transcribed into messenger ribonucleic acid (mRNA), which is then translated into amino acids, the subunits of the proteins required for life. DNA is constantly subjected to damage by both internal (endogenous) and external (exogenous) assaults. This damage can lead to blocks in transcription and replication or to permanent alterations in the genetic code, and can ultimately lead to disease and death of the organism. It has been reported that up to 90% of human cancers are associated with DNA damage. Because the survival of an organism depends upon precise transcription and replication of its genome, several mechanisms of DNA repair have evolved. In general, these repair systems are universal, correcting defects in the genomes of organisms as diverse as microbes and humans.
Industry:Science
At the turn of the twentieth century, Nikola Tesla devoted his extraordinary abilities to pioneering research on radio-frequency electromagnetism, with the ultimate goal of perfecting a system for delivering electric power wirelessly over continental distances. Although Tesla's dream was not fully realized, this work led directly to the development of the radio. In recent years, there has been a proliferation of portable electronic devices, most of which rely on modern developments of radio technology to transfer data wirelessly. These devices are frequently marketed as wireless, although the consumer must still plug them into a power outlet regularly, at least to recharge their batteries. A method for supplying energy without cables, particularly if the source of wireless power and the receiving object are separated by midrange distances of at least several feet, could make these devices completely wireless.
Industry:Science
Biologists have long commented on how the vertebrate skeleton appears to be designed in accordance with engineering principles. Bones and their associated soft tissues are adapted to transmit, resist, and take advantage of the many forces the skeleton experiences during normal function. How bones respond to forces, that is, how they are stressed and strained, is therefore linked to their function. A great deal of functional information can be gained from examining how a skeleton responds to stresses and strains; yet paleontologists are limited because fossil bones are petrified (and thus have different properties than biomaterials in living animals), and skulls in particular are complex shapes not applicable to straightforward mathematical analysis. Recently, however, biologists and paleontologists have begun to borrow from the sophisticated design toolkit of engineers in order to examine skeletal construction.
Industry:Science
Biomedical applications of micro-electro-mechanical systems, or BioMEMS, is an emerging field that uses techniques adapted from the microelectronics industry to create devices for sensing and manipulating biological material with a precision not previously possible. For example, microfabrication technology is being applied to create drug delivery systems that allow tight control over physical parameters such as fluid flow rates and pressure, enabling precise delivery of concentrated drug solutions in order to meet dosage specifications of drugs. By integrating microfabricated devices such as microneedles and micropumps, very tight control over injection flow rates at given drug concentrations can be achieved. Drug solutions may be administrated as needed by the patient. Thus, the drug concentration in the body may be controlled to achieve either a constant or time-varying drug concentration profile in the body.
Industry:Science
Cirrus are thin, wispy clouds that appear at high altitude and consist of ice crystals. At midlatitudes, clouds with base heights above about 6 km (20,000 ft) are designated as high clouds, a category that includes cirrus (Ci), cirrostratus (Cs), and cirrocumulus (Cc). Cirrus clouds are globally distributed at all latitudes over land or sea at any season of the year. They undergo continuous changes in area coverage, thickness, texture, and position. The most striking cirriform cloud features are produced by weather disturbances in midlatitudes. In the tropics, cirrus clouds are related to outflows from tower cumulus associated with the convective activity over the oceans. The global cirrus cover has been estimated to be about 20–25%, but recent analysis using the satellite infrared channels at the 15-micrometer carbon dioxide (CO<sub>2</sub>) band has shown that their occurrence is more than 70% over the tropics.
Industry:Science
Geometrical objects that are self-similar under a change of scale, for example, magnification. The concept is helpful in many disciplines to allow order to be perceived in apparent disorder. For instance, in the case of a river and its tributaries, every tributary has its own tributaries so that it has the same structural organization as the entire river except that it covers a smaller area. The branching of trees and their roots as well as that of blood vessels, nerves, and bronchioles in the human body follows the same pattern. Other examples include a landscape with peaks and valleys of all sizes, a coastline with its multitude of inlets and peninsulas, clouds, lightning, the mass distribution within a galaxy, the distribution of galaxies in the universe, and the structure of vortices in a turbulent flow. The rise and fall of economic indices has a self-similar structure when plotted as a function of time.
Industry:Science
Color vision is the ability to distinguish among light stimuli based solely on differences in their spectra, independent of brightness, polarization, or any other stimulus feature. To make such discriminations, at least two receptor classes with different sensitivity spectra must exist in the retina. In vertebrates, this generally means that two cone spectral classes are present. While invertebrate photoreceptors vary in their cellular structure, two or more types must nevertheless be present to provide color vision. Because color vision involves internal processing to distinguish among stimuli, it cannot be demonstrated by physiological means alone. The definitive proof that an animal possesses this ability requires rigorous behavioral testing to show that it can make the required discriminations. Often, this is difficult to do, so it is not always a simple matter to show that color vision is present in a given species.
Industry:Science
