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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.
In a narrow sense, the electromagnetic radiation emitted by electrons when they pass through matter. Charged particles radiate when accelerated, and in this case the electric fields of the atomic nuclei provide the force which accelerates the electrons. The continuous spectrum of x-rays from an x-ray tube is that of the bremsstrahlung; in addition, there is a characteristic x-ray spectrum due to excitation of the target atoms by the incident electron beam. The major energy loss of high-energy (relativistic) electrons (energy greater than about 10 MeV, depending somewhat upon material) occurs from the emission of bremsstrahlung, and this is the major source of gamma rays in a high-energy cosmic-ray shower.
Industry:Science
Bursts of electromagnetic radiation of finite duration. Optical pulses are used to transmit information or to record the chronology of physical events. The simplest example is the photographic flash. This was probably first developed by early photographers who used flash powder that, when ignited, produced a short burst of intense light. This was followed by the flash lamp, in which a tube filled with an inert gas such as xenon is excited by a brief electrical pulse. A great advance in the creation of short optical pulses came with the invention of the laser. Lasers are now the most common and effective way of generating a variety of short optical pulses, of different durations, energies, and wavelengths.
Industry:Science
Any disorder of higher mental processes of such severity that judgments pertaining to the reality of external events are significantly impaired. A wide range of psychiatric, medical, and neurological conditions can bring about a psychotic state. They include schizophrenia, mania, depression, ingestion of drugs, withdrawal from drugs, liver or kidney failure, endocrine disorders, metabolic disorders, and Alzheimer's disease, epilepsy, and other neurologic dysfunctions. Not all psychotic states are caused by disease or drugs. The dreams of normal sleep are a form of psychosis; while dreaming, a reality can be seen and heard which, at the moment, is not known to be false but which is roused from upon awakening.
Industry:Science
Approximately 1 out of every 2000 infants is born profoundly deaf, and more than one-third of people born with normal hearing will have a significant hearing loss by their 60s. Hearing loss has a variety of causes, including trauma (such as a head injury), illness (such as rubella or meningitis), the environment (notably, long-term exposure to loud noise), drugs (including some powerful chemotherapy agents and certain antibiotics), genetics, or some combination of these factors. Genetic hearing loss has not been well understood until recently, when several of the responsible genes were identified. The hearing loss that results from inherited defects in these genes can be divided into syndromic and nonsyndromic.
Industry:Science
Computers that can speak and understand natural language have long appeared in science fiction. Endowing computers with linguistic capabilities in practice, however, has proven to be exceptionally difficult. Efforts to build automatic translation machines started in the early days of functional computers in the 1950s, and the complex problems thwarted researchers for decades. Recently, however, significant progress has been made, and while machines are far from fully understanding language, useful applications involving language are now possible. Linguistic capabilities can be expected to appear in a wide range of products and applications and to transform the way people think about and interact with computers.
Industry:Science
Chemotherapy is the use of chemicals to treat any disease, but the term has come to be applied most commonly to the use of drugs to treat cancer and that exhibit cytotoxic activity through inhibition of cell division. Recently, several other classes of drugs (biologicals) started to be used to treat cancer, often in conjunction with conventional chemotherapy. Cancer is an abnormal growth or proliferation of cells that tends to invade locally or spread to distant parts of the body. Several treatment modalities can be used for cancer. Surgery physically removes the abnormal growth, whereas radiation, immunotherapy, hormonal therapy, and chemotherapy are directed at killing or slowing the growth of cancerous cells.
Industry:Science
From molecular biology and chemistry to astronomy, earth sciences, and particle physics, modern experimental science relies increasingly on the acquisition, manipulation, and processing of large amounts of data, and the systematic orchestration of computationally intensive simulations and analyses. Much of the analysis is expensive in terms of the data processing and storage resources required, and it sometimes runs for weeks and needs careful monitoring. It is also laboriously repetitive as scientists explore different settings for their algorithms, data sets are continually updated from instruments, and new information prompts the whole “in silico” (computer-simulated) experiment to be rerun and cross-checked.
Industry:Science
Disorders of the kidney are classified by both their etiology and their anatomic location along the nephron. Disorders other than those arising from tumors become evident when the kidney is unable to regulate the volume and composition of the extracellular fluids, resulting in edema and hypertension. The clinical signs cannot identify the specific segment of the nephron that is affected, since overall renal function depends on each segment functioning in sequence. The failure of one part, therefore, affects the functioning of the whole unit and makes a precise diagnosis difficult without a kidney biopsy. Knowing the location and type of abnormality is important because it may determine the prognosis or therapy.
Industry:Science
Approximately 2.7 billion years ago, braided rivers transported mud and sand from the land of a small continent to the sea. The sand on the riverbanks and beaches contained pyrite crystals preserved in an atmosphere low in oxygen. The continent possessed no life form. However, the ocean teemed with single-celled organisms that floated close to the surface. In the shallows, microorganisms lived in matlike communities on the sea floor and grew layer by layer closer to the sunlight, forming domelike, finely laminated structures. Some of these stromatolites attained a height of several meters. Later, this continent, called the Pilbara, would collide with other plates of continental crust to form the Australian mainland.
Industry:Science
Human immunodeficiency virus (HIV) enters target cells by a process involving direct fusion between the virus and cell membranes. This process begins when the HIV envelope glycoprotein (Env) binds to CD4, the primary receptor on the target cell surface. It has long been recognized that CD4 alone is not sufficient to allow HIV entry; an additional “coreceptor” on the target cell is required. Evidence has suggested that the tropism of different HIV strains for infection of various target cell types (for example, T-cell lines, macrophages, primary T cells) results from the ability of the corresponding Envs to use distinct coreceptors, which in turn are differentially expressed on various CD4-positive target cell types.
Industry:Science
