- 行业: Printing & publishing
- Number of terms: 178089
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- Company Profile:
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 Galileo program is a European-sponsored satellite navigation program that is to provide worldwide navigation and time services to a large variety of transportation, telecommunication, scientific, recreational, and other applications. Although Galileo is similar in many ways to the Global Positioning System (GPS) of the United States, it is primarily dedicated to civil users and plans to be independent of but interoperable with GPS. As Europe's largest collaborative project to date, Galileo promises to unite many European technical and management resources in the development of a significant satellite-based global navigation and timing system capability. It is expected to provide long-term economic and system performance benefits to Europe and to the world.
Industry:Science
The <i>Vela</i> defense satellites were launched in the 1960s to monitor a treaty that forbade nuclear explosions in space. The <i>Vela</i> satellites did not detect any nuclear explosions. However, a serendipitous by-product of this mission was the discovery of celestial gamma-ray bursts (GRBs): short and intense pulses of gamma rays arriving from random directions in the sky. Several times a day a cosmic explosion takes place somewhere in the universe, and its echoes reach us as a burst of gamma rays. The burst appears suddenly, lasts for a few seconds, and then fades and disappears forever. The lack, until recently, of any long-lasting counterparts to these short bursts hindered their study, making them one of the most puzzling phenomena in modern astronomy.
Industry:Science
The ability of a planetary atmosphere to inhibit heat loss from the planet's surface, thereby enhancing the surface warming that is produced by the absorption of solar radiation. For the greenhouse effect to work efficiently, the planet's atmosphere must be relatively transparent to sunlight at visible wavelengths so that significant amounts of solar radiation can penetrate to the ground. Also, the atmosphere must be opaque at thermal wavelengths to prevent thermal radiation emitted by the ground from escaping directly to space. The principle is similar to a thermal blanket, which also limits heat loss by conduction and convection. In recent decades the term has also become associated with the issues of global warming and climate change induced by human activity.
Industry:Science
The absorbing and anchoring organ of vascular plants. Roots are simple axial organs that produce lateral roots, and sometimes buds, but bear neither leaves nor flowers. Elongation occurs in the root tip, which is usually 0.004–0.04 in. (0.1–1.0 mm) in diameter and 0.4–4 in. (1–10 cm) long. The older portion of the root, behind the root tip, may thicken through cambial activity. Some roots, grass for example, scarcely thicken, but tree roots can become 4 in. (10 cm) or more in diameter near the stem. Roots may be very long. The longest maple (<i>Acer</i>) roots are usually as long as the tree is tall, but the majority of roots are only a few centimeters long. The longest roots may live for many years, while small roots may live for only a few weeks or months.
Industry:Science
The assemblies of switching and control devices provided so that any station in a communications system may be connected as desired with any other station. A telecommunications network consists of transmission systems, switching systems, and stations. Transmission systems carry messages from an originating station to one or more distant stations. They are engineered and installed in sufficient quantities to provide a quality of service commensurate with the cost and expected benefits. To enable the transmission facilities to be shared, stations are connected to and reached through switching system nodes that are part of most telecommunications networks. Switching systems act under built-in control to direct messages toward their ultimate destination or address.
Industry:Science
The creation of assemblies of nuclei whose spin axes are not oriented at random, and which are in a steady state that is not a state of thermal equilibrium. Under commonly occurring conditions, the spin axes of nuclei (with nonzero spin) are oriented at random; where this is not so, the nuclei are said to be polarized. Assemblies of polarized nuclei are not in a state of thermal equilibrium except under rather extreme conditions (for example, temperatures below 10 millikelvins or 0.02°F above absolute zero, and magnetic fields greater than several teslas), and schemes have been devised to produce polarized assemblies, in a steady state which is not a state of thermal equilibrium, under less extreme conditions. Such schemes constitute dynamic nuclear polarization.
Industry:Science
The determination of three parameters: the size of an air sample, its speed, and its direction of motion. Air movement or wind is a vector that is specified by speed and direction; meteorological convention indicates wind direction is the direction from which the wind blows (for example, a southeast wind blows toward the northwest). Anemometers measure wind speed, while wind vanes indicate direction. On average, the wind blows horizontally over flat terrain; however, gusts, thermals, cloud outflows, and many other conditions have associated with them significant short-term vertical wind components. While research wind instruments typically measure both horizontal and vertical air movement, operational and personal wind sensors measure only the horizontal component.
Industry:Science
Stromatolites are laminated sedimentary deposits created by benthic (bottom-dwelling) microbial organisms, primarily bacteria and cyanobacteria but also eukaryotic algae, capable of trapping, binding, and cementing sediment grains in thin layers. These kinds of organisms remain an important constituent in many marine communities, including reefs, but are easily overlooked because of their tiny size, unfamiliar morphology, uncertain taxonomic affinities, and obscurity in recrystallized or metazoan-dominated samples. Stromatolites first appeared on Earth 3.5 billion years ago and were the earliest ecosystems to evolve on the planet. Their abundance in the Precambrian geologic record indicates microorganisms were the only common forms of life for more than 3 billion years.
Industry:Science
The garden pepper, <i>Capsicum annuum</i> (family Solanaceae), is a warm-season crop originally domesticated in Mexico. It is usually grown as an annual, although in warm climates it may be perennial. This species includes all peppers grown in the United States except for the “Tabasco” pepper (<i>C</i>. <i>frutescens</i>), grown in Louisiana. Other cultivated species, <i>C</i>. <i>chinense</i>, <i>C</i>. <i>baccatum</i>, and <i>C</i>. <i>pubescens</i>, are grown primarily in South America. Some 10–12 strictly wild species also occur in South America. Peppers are grown worldwide, especially in the more tropical areas, where the pepper is an important condiment. <i>Piper nigrum</i>, the black pepper, a tropical climbing vine, is botanically unrelated to the common pepper.
Industry:Science
The correction of a cellular defect caused by mutations in a gene by the addition of the normal gene or its product (protein). In cell cultures, complementation can be accomplished by transfer of deoxyribonucleic acid (DNA) or messenger ribonucleic acid (mRNA) that encodes this protein. Another way to “complement” a cellular defect is by joining two chromosome sets in the same cell, each defective due to a different mutation but together able to correct the cellular defect. This principle is used in somatic cell hybridization (or cell fusion), in which cells are fused to generate hybrid cells that possess all chromosomes from both fusion partners. Such hybrids are usually viable and can be examined for the presence of the cellular deficiency via complementation analysis.
Industry:Science
