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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.
Means for regulating the operation of a steam-generating unit to produce steam at the required temperature. The temperature of steam is affected by the change in the relative heat absorption as load varies, by changes in ash or slag deposits on the heat-absorbing surface, by changes in fuel, by changes in the proportioning of fuel and combustion air, or by changes in feedwater temperature. Low steam temperature lowers the efficiency of the thermal cycle. However, high steam temperature, which increases thermal efficiency, is restricted by the strength and durability of materials used in superheaters. Control of steam temperature is, therefore, a matter of primary concern in the design of modern steam-generating units.
Industry:Science
In recent years, the growing problem of antibiotic resistance has enabled diseases once on the verge of eradication, such as tuberculosis, to reemerge as major threats to human health. The resurgence of old diseases, as well as the appearance of new ones, has prompted scientists to examine closely the factors that enable pathogens (disease-causing organisms) to invade and persist in human populations. Together, the problems of emerging infectious diseases and antibiotic resistance have fueled the development of the field known as evolutionary epidemiology. Fundamental to this new discipline is the recognition that pathogens are themselves biological entities that evolve in response to the challenges of their environment.
Industry:Science
In the spring of 2006, the world watched in dismay as Barbaro, a promising young Thoroughbred racehorse, shattered his right hind leg at the start of the Preakness Stakes at the Pimlico Race Course in Maryland. After multiple operations on the fractured leg, Barbaro's many fractures eventually healed; however, along the way he developed laminitis, first in his left hindfoot and later in both front feet. This disease ultimately contributed to the loss of the 2006 Kentucky Derby champion because of the chronic pain and the poor prognosis for any reasonable quality of life. The silver lining in this sad tale is that more research funds are now being directed toward the prevention and treatment of laminitis than ever before.
Industry:Science
Restoration ecology is the investigation of ecological principles and field methodologies that increase the ability to successfully alter ecosystems for restoration. This process requires transforming an area into a precisely defined, indigenous historic ecosystem that replicates the structure, function, diversity, and dynamics of the ecosystem. It is practiced across a wide variety of natural communities (such as grasslands, forests, wetlands, lakes, and rivers), and is done for a number of purposes (such as detoxifying polluted lands, creating habitat for endangered species, and restoring natural beauty to parks for human enjoyment). Restoration is a challenging task, and to date, most restoration projects have failed.
Industry:Science
Rotation of the plane of polarization of a beam of linearly polarized light when the light passes through matter in the direction of the lines of force of an applied magnetic field. Discovered by M. Faraday in 1846, the effect is often called magnetic rotation. The magnitude α of the rotation depends on the strength of the magnetic field <i>H</i>, the nature of the transmitting substance, the frequency <i>v</i> of the light, the temperature, and other parameters. In general, α = <i>VxH</i>, where <i>x</i> is the length of the light path in the magnetized substance and <i>V</i> the so-called Verdet constant. The constant <i>V</i> is a property of the transmitting substance, its temperature, and the frequency of the light.
Industry:Science
One of a number of techniques used in the preparation of high-purity materials. The technique is capable of producing very low impurity levels, namely, parts per million or less in a wide range of materials, including metals, alloys, intermetallic compounds, semiconductors, and inorganic and organic chemical compounds. In principle, zone refining takes advantage of the fact that the solubility level of an impurity is different in the liquid and solid phases of the material being purified; it is therefore possible to segregate or redistribute an impurity within the material of interest. In practice, a narrow molten zone is moved slowly along the complete length of the specimen in order to effect the impurity segregation.
Industry:Science
On February 1, 2003, the space shuttle <i>Columbia</i> disintegrated over the southern United States during reentry. The Columbia Accident Investigation Board (CAIB) was formed and issued their report in August 2003. The report was organized into three sections: (1) “The Accident,” which summarized the shuttle program, the <i>Columbia</i>' final flight, and the accident's physical cause; (2) “Why the Accident Occurred,” which compared <i>Challenger</i> to <i>Columbia</i> with emphasis on organizational reasons for the accident; and (3) “A Look Ahead,” which looked at near-, mid-, and long-term implications of the accident for United State space flight. In each section, the report presented many findings and recommendations.
Industry:Science
Modulation in which the instantaneous angle varies in proportion to the modulating waveform. When used in an analog manner, it is referred to as either frequency modulation (FM) or phase modulation (PM), depending upon whether the instantaneous frequency or instantaneous phase varies with the modulation. When used in a digital modulation format, it is referred to as either frequency-shift keying (FSK) or phase-shift keying (PSK). Both FSK and PSK can be used with either a binary or an <i>M</i>-ary alphabet, where <i>M</i> is an integer greater than 2. Indeed, the most common forms of PSK correspond to an input alphabet size of either two or four; while for FSK alphabets of two, four, or eight, symbols are typically employed.
Industry:Science
One of the strongest of the hard fibers, commercially known as Manila hemp. Abaca is obtained from the leafstalks of a member of the banana family, <i>Musa textilis</i>. The plant resembles the fruiting banana, but is a bit shorter in stature, bears small inedible fruits, and has leaves that stand more erect than those of the banana and are slightly narrower, more pointed, and 5–7 ft (1.5–2 m) long. Relatives of abaca grow wild throughout Southeast Asia, but the plant was domesticated long ago in the southern Philippines. Experiments have succeeded in growing plants yielding fiber in a few other parts of the world, chiefly Middle America, but commercial production has come almost entirely from the Philippines and Borneo.
Industry:Science
In magnetic random access memories (MRAMs), submicrometer-size magnetic structures store digital information in their magnetic orientation. In the most common architecture, the stored information can be retrieved by sensing the electrical resistance difference that exists in the magnetic structures between the two possible magnetization directions, using an effect called giant magnetoresistance. As long as the bit is not rewritten, the information is maintained; hence MRAM is a nonvolatile memory. The most appealing characteristics of MRAM are its miniaturization to deep submicrometer memory bits, its unlimited read-write capability, and its fast access. MRAM circuits are expected to be available in consumer products by 2003.
Industry:Science
