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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 algorithms and computers utilized to steer a vehicle along a path. The types of vehicles include airplanes, rockets, missiles, ships, torpedoes, drones, and material transport vehicles within factories and so forth. The means of steering depend on the vehicle and can be the rudder, elevators, and other control surfaces on an airplane, the rudder on a ship, the control surfaces on a missile or on a torpedo, the gimbal angle of the motor on a rocket, and others. In every case the guidance system utilizes knowledge of the difference between where the vehicle should be and where it is. The difference between these two vectors is processed by the guidance algorithm. The output is a steering command intended to reduce the error between the desired and the actual paths.
Industry:Science
The ability of a population to persist and to avoid extinction. The viability of a population will increase or decrease in response to changes in the rates of birth, death, and growth of individuals. In natural populations, these rates are not stable, but undergo fluctuations due to external forces such as hurricanes and introduced species, and internal forces such as competition and genetic composition. Such factors can drive populations to extinction if they are severe or if several detrimental events occur before the population can recover. The concept of population viability gained importance with the National Forest Management Act of 1976, which charged the U.S. Forest Service with maintaining “viable populations” of all species of vertebrates found on its properties.
Industry:Science
The behavior of a quantum system whose classical motion could involve chaotic behavior is called quantum chaos. Chaos can arise in a classical system—a system of objects which are large compared to atomic scale—when the equations governing its behavior are nonlinear. Chaos in this classical sense generally cannot be found in a system fully described by quantum mechanics, since the Schrödinger equation, which describes quantum systems, is linear. The correspondence principle requires that a result obtained from quantum mechanics approach the classical result in the classical limit, that is, the limit of large size. The primary issues in quantum chaos in a three-body system are what are the signs of chaos, and how large the quantum system has to be to display chaotic behavior.
Industry:Science
The application of results of basic research and of engineering principles to the solution of practical fire protection problems, but entailing, in its own right, research into fire phenomena and fire experience to provide an improved level of understanding of the nature of unwanted fire and its threat to life and property. The defense against destructive fire has been largely empirical and improvisational; although this approach has been reasonably effective in the past, it has not kept pace with urbanized and industrialized life. However, an impressive array of scientific and engineering disciplines has been brought to bear on the complex practical problems of fire defense. This article reviews the current state of fire technology, principally as it applies to urban fires.
Industry:Science
The design and use of optical interferometers. Optical interferometers based on both two-beam interference and multiple-beam interference of light are extremely powerful tools for metrology and spectroscopy. A wide variety of measurements can be performed, ranging from determining the shape of a surface to an accuracy of less than a millionth of an inch (25 nanometers) to determining the separation, by millions of miles, of binary stars. In spectroscopy, interferometry can be used to determine the hyperfine structure of spectrum lines. By using lasers in classical interferometers as well as holographic interferometers and speckle interferometers, it is possible to perform deformation, vibration, and contour measurements of diffuse objects that could not previously be performed.
Industry:Science
2</span>, meaning that its spin angular momentum is 3/√<span style="border-top:1px solid black;">2</span><i>h</i>.">The intrinsic angular momentum of a particle. It is that part of the angular momentum of a particle which exists even when the particle is at rest, as distinguished from the orbital angular momentum. The total angular momentum of a particle is the sum of its spin and its orbital angular momentum resulting from its translational motion. The general properties of angular momentum in quantum mechanics imply that spin is quantized in half integral multiples of ℏ (<i>h</i>/2π, where <i>h</i> is Planck's constant); orbital angular momentum is restricted to half <i>even</i> integral multiples of ℏ. A particle is said to have spin 3/√<span style="border-top:1px solid black;">2</span>, meaning that its spin angular momentum is 3/√<span style="border-top:1px solid black;">2</span><i>h</i>.
Industry:Science
The alpha polymorph of calcium silicate (Ca<sub>2</sub>SiO<sub>4</sub>). Larnite is a mineral which crystallizes at high temperature. Its occurrences are practically confined to limestone or chalk zones in contact with semimolten balsalts. The presence of magnesium leads to the formation of other structurally related high-temperature minerals such as merwinite (Ca<sub>3</sub>Mg(SiO<sub>4</sub>)<sub>2</sub>), bredigite (Ca<sub>7</sub>Mg(SiO<sub>4</sub>)<sub>4</sub>), and alite (Ca<sub>3</sub>O(SiO<sub>4</sub>)). These phases are structurally very dense and have been postulated as possible components in the Earth's mantle. At least four polymorphs of Ca<sub>2</sub>SiO<sub>4</sub> are known, and a few others are stabilized by impurities. They often occur in silicate slags and clinkers.
Industry:Science
The emission of electrons from a metal or semiconductor into vacuum (or a dielectric) under the influence of a strong electric field. In field emission, electrons tunnel through a potential barrier, rather than escaping over it as in thermionic emission or photoemission. The effect is purely quantum-mechanical, with no classical analog. It occurs because the wave function of an electron does not vanish at the classical turning point, but decays exponentially into the barrier (where the electron's total energy is less than the potential energy). Thus there is a finite probability that the electron will be found on the outside of the barrier. This probability varies as <i>e</i><sup>-<i>cA</i><sup>1/2</sup></sup>, where <i>c</i> is a constant and <i>A</i> the area under the barrier.
Industry:Science
The asexual creation of a genetic copy, a capability possessed by plants but not by most animals. Thus, plants generate genetic copies spontaneously, and rooting “cuttings” is widely used by horticulturists to propagate millions of clones annually. In animals, only some lower invertebrates can be cloned by “cutting”; for example, earthworms when bisected will regenerate the missing half, resulting in two whole, genetically identical individuals. However, asexual reproduction and cloning do not normally occur in vertebrates except for the special case of identical twinning. This is despite the fact that individual cells, called blastomeres, within the very early embryo are totipotent; that is, each is capable, if evaluated on its own, of developing into a viable term pregnancy and infant.
Industry:Science
The burning of any substance, in gaseous, liquid, or solid form. In its broad definition, combustion includes fast exothermic chemical reactions, generally in the gas phase but not excluding the reaction of solid carbon with a gaseous oxidant. Flames represent combustion reactions that can propagate through space at subsonic velocity and are accompanied by the emission of light. The flame is the result of complex interactions of chemical and physical processes whose quantitative description must draw on a wide range of disciplines, such as chemistry, thermodynamics, fluid dynamics, and molecular physics. In the course of the chemical reaction, energy is released in the form of heat, and atoms and free radicals, all highly reactive intermediates of the combustion reactions, are generated.
Industry:Science
