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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.
An outstanding problem in vertebrate paleobiology is the origin of vertebrates, which has been an issue for well over a hundred years. How are vertebrates related to invertebrates; what characteristics are specific to vertebrates in terms of their body plan; and what genetic innovations were necessary in order to develop these vertebrate-specific features remain questions. Answers are not likely to be found in the fossil record of early vertebrates, but require tools that have come into use only recently.
Industry:Science
Any two-terminal solid-state device in which the electric current <i>I</i> increases considerably faster than the voltage <i>V</i>. This nonlinear effect may occur over all, or only part, of the current-voltage characteristic. It is generally specified as <i>I</i>∝<i>V</i><sup><i>n</i></sup>, where <i>n</i> is a number ranging from 3 to 35 depending on the type of varistor. The main use of varistors is to protect electrical and electronic equipment against high-voltage surges by shunting them to ground.
Industry:Science
For thousands of years the oceans have provided humankind with food and trade routes, and more recently with petroleum and minerals to fuel society. Since the 1960s, there has been a dramatic change in the general view of the oceans and the human impact on their sustaining ecosystems. In past times, little regard was given to disposal of wastes from ships. As greater understanding of the marine environment developed, it became clear that human behavior must change to ensure the health of that environment.
Industry:Science
Beans, corn, rice, and other grains are excellent foods for insects. Stored-grain insects, such as weevils and moths, destroy billions of dollars of grain each year throughout the world. Moreover, foods prepared with insect-contaminated grain can have unpleasant flavors, be unhygienic, or even be inedible. On subsistence farms in Africa, weevily grain may be fed to the chickens or goats in the hope of rescuing a little value from it. Insect-damaged grain germinates less well and is more subject to disease.
Industry:Science
Diseases caused by mycobacteria, a diffuse group of acid-fast, rod-shaped bacteria in the genus <i>Mycobacterium</i>. Some mycobacteria are saprophytes, while others can cause disease in humans. The two most important species are <i>M. tuberculosis</i> (the cause of tuberculosis) and <i>M. leprae</i> (the cause of leprosy); other species have been called by several names, particularly the atypical mycobacteria or the nontuberculous mycobacteria. This article deals mainly with nontuberculous mycobacteria.
Industry:Science
Fleas, mites, mosquitoes, and other small-scale “living microsystems” have found an ecological niche that is in many ways unparalleled in nature. In the last few years, the convergence of a number of advances in micro-electro-mechanical-systems (MEMS) technology (including power generation, energy storage, communications, sensing, microfluidics, and subcomponent assembly) has opened the door to creating artificial autonomous microsystems that have many of the same capabilities of their living counterparts.
Industry:Science
Any machine that can accomplish its specific task in the presence of uncertainty and variability in its environment. The machine's ability to monitor its environment and then adjust its actions based on what it has sensed is a prerequisite for intelligence. The term intelligent machine is an anthropomorphism in that intelligence is defined by the criterion that the actions would appear intelligent if a person were to do it. A precise, unambiguous, and commonly held definition of intelligence does not exist.
Industry:Science
Banded iron formation (BIF) is a chemical sedimentary rock containing >15 wt% iron (Fe). Most commonly, Fe-rich layers alternate with chert, although they may also be interbedded with layers made up of carbonate or silicate minerals, or sulphidic shale. As the major source of iron ore, BIF is of crucial economic importance. Sedimentologic and geochemical investigations of BIF continue to yield significant insights into the chemistry of the Precambrian atmosphere-hydrosphere system and the evolution of life.
Industry:Science
Formulas in quantum mechanics for transitions between energy levels, in which the sum of the transition strengths is expressed in a simple form. Sum rules are used to describe the properties of many physical systems, including solids, atoms, atomic nuclei, and nuclear constituents such as protons and neutrons. The sum rules are derived from quite general principles, and are useful in situations where the behavior of individual energy levels is too complex to describe by a precise quantum-mechanical theory.
Industry:Science
Ebola viruses are a group of exotic viral agents that cause a severe hemorrhagic fever disease in humans and other primates. The four known subtypes or species of Ebola viruses are Zaire, Sudan, Reston, and Côte d'Ivoire (Ivory Coast), named for the geographic locations where these viruses were first determined to cause outbreaks of disease. Ebola viruses are very closely related to, but distinct from, Marburg viruses. Collectively, these pathogenic agents make up a family of viruses known as the Filoviridae.
Industry:Science
