- 行业: Printing & publishing
- Number of terms: 178089
- Number of blossaries: 0
- 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.
An acid which has an extremely great proton-donating ability. It has proved convenient to define a superacid somewhat arbitrarily as an acid, or more generally, an acid medium, which has a proton-donating ability equal to or greater than that of anhydrous (100%) sulfuric acid.
Industry:Science
An acidic, chainlike biological macromolecule consisting of multiply repeated units of phosphoric acid, sugar, and purine and pyrimidine bases. Nucleic acids as a class are involved in the preservation, replication, and expression of hereditary information in every living cell. There are two types: deoxyribonucleic acid (DNA) and ribonucleic acid (RNA).
Industry:Science
An acoustic device consisting of a rigid cavity with one or more small openings. When exposed to sound or vibration, a Helmholtz resonator responds most strongly near a characteristic resonance frequency governed by the dimensions of its cavity and openings. A common example is a bottle or jug that produces sound near its resonance frequency when air is blown over the neck's opening. The Helmholtz resonator is named after the physicist and physiologist Hermann von Helmholtz, who constructed spherical glass resonators with small openings at opposite ends to analyze the frequency content of sounds, including musical tones.
Industry:Science
A planning, scheduling, and control procedure based upon the use of time-oriented networks which reflect the interrelationships and dependencies among the project tasks (activities). The major objectives of PERT are to give management improved ability to develop a project plan and to properly allocate resources within overall program time and cost limitations, to control the time and cost performance of the project, and to replan when significant departures from budget occur.
Industry:Science
An acronym for radio detection and ranging, the original and basic function of radar. The name is applied to both the technique and the equipment used. Radar is a sensor; its purpose is to provide estimates of certain characteristics of its surroundings of interest to a user, commonly the presence, position, and motion of aircraft, ships, or other vehicles in its vicinity. In other uses, radars provide information about the Earth's surface (or that of other astronomical bodies) or about meteorological conditions. To provide the user with a full range of sensor capability, radars are often used in combinations or with other elements of the complete system.
Industry:Science
A highly sensitive magnetometer used to measure extremely weak magnetic fields. The device is designed based on superconducting loops containing Josephson junctions. The term actually refers to two different types of device, the dc SQUID and the rf SQUID.
Industry:Science
An act of destroying all forms of life on and in an object. A substance is sterile, from a microbiological point of view, when it is free of all living microorganisms. Sterilization is used principally to prevent spoilage of food and other substances and to prevent the transmission of diseases by destroying microbes that may cause them in humans and animals.
Industry:Science
An actively functioning endocrine gland, located in the brain, which secretes melatonin, is strongly regulated by light stimuli, and is an important component of the circadian timing system. The pineal gland or pineal body has the Latin name <i>epiphysis cerebri</i>. It is virtually ubiquitous throughout the vertebrate animal kingdom. In nonmammalian vertebrates (lampreys, fishes, amphibians, reptiles, birds), it functions as a photoreceptive third eye and an endocrine organ. In mammals, it serves as an endocrine organ that is regulated by light entering the body via the paired eyes. In all vertebrates, including humans, the pineal gland produces the hormone melatonin, with the highest synthesis and secretion occurring during the night. Despite extensive species variation in anatomy and physiology, the pineal gland generally serves as an essential component of the circadian system which allows animals to internally measure time and coordinate physiological time-keeping with the external environment.
Industry:Science
An acute contagious disease that is a consequence of infection with <i>Streptococcus pyogenes</i> (group A streptococci). It most often accompanies pharyngeal (throat) infections with this organism but is occasionally associated with wound infection or septicemia. Scarlet fever is characterized by the appearance, about 2 days after development of pharyngitis, of a red rash that blanches under pressure and has a sandpaper texture. Usually the rash appears first on the trunk and neck and spreads to the extremities. The rash fades after a week, with desquamation, or peeling, generally occurring during convalescence. Like streptococcal pharyngitis without such a rash, the disease is usually self-limiting, although severe forms are occasionally seen with high fever and systemic toxicity. Appropriate antibiotic therapy is recommended to prevent the onset in susceptible individuals of rheumatic fever and rheumatic heart disease.
Industry:Science
An acute contagious viral disease, characterized chiefly by enlargement of the parotid glands (parotitis). The virus, 175–200 nanometers in diameter, is a member of the <i>Paramyxovirus</i> genus in the family <i>Paramyxoviridae</i>. It will grow in monkeys, newborn hamsters, embryonated eggs, and tissue cultures.
Industry:Science
