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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.
Biofuel cells produce electrical energy from organic materials using electrochemical processes that are catalyzed by biological substances (enzymes or whole microbial cells). In contrast, regular fuel cells use inorganic catalysts (such as platinum) to enhance the electrochemical processes. Most organic substrates (reactants) undergo combustion with the evolution of energy. The biocatalyzed oxidation of organic substrates by oxygen or other oxidizers at two electrode interfaces provides a means for converting chemical energy to electrical energy.
Abundant organic raw materials, such as alcohols, organic acids, or sugars, can be used as substrates for the oxidation process. Molecular oxygen (O<sub>2</sub>) or hydrogen peroxide (H<sub>2</sub>O<sub>2</sub>) can act as the substrate for the reduction process. The organic materials are oxidized at the electrode, called the anode, generating electrons which go through the external electrical circuit to the electrode, called the cathode, where they are accepted by the oxidizer. This process generates the electrical power (voltage and current) released by the biofuel cell. In order to produce continuous electrical power, aqueous solutions containing the organic fuel and the oxidizer are pumped to the respective electrodes in the biofuel cell, where these electrochemical processes take place.
Industry:Science
Climate is an important influence on both the environment and society. Year-to-year climate variations are reflected in such things as the number and intensity of storms, the amount of water flowing in rivers, the extent and duration of snow cover, ocean-current-induced changes in sea level, and the intensity of waves that strike coastal regions and erode the shoreline. These factors in turn determine agricultural productivity, the occurrence of floods and droughts, the safety of communities, and the general productivity of society.
Science now suggests that human activities are causing the natural climate to change, mainly by inducing global warming and an associated intensification of the global hydrologic cycle. Although details are still emerging about the magnitude, regional pattern, and timing of the changes projected for this century, it is widely recognized that climate will be changing. Indeed, temperatures have already increased in many areas, Arctic sea ice is much thinner, continental snow cover is not lasting as long in the spring, and total precipitation is increasing, with more rainfall occurring in intense downpours. These changes also appear to be affecting the distribution of plants and wildlife. There is evidence of a longer growing season in northern areas, and of changing ranges for butterflies and other species.
Industry:Science
Distinctive associations of third-order, erosional landforms indented into second-order structural forms such as plains and plateaus. They are produced by aqueous dissolution, either acting alone or in conjunction with (and as the trigger for) other erosion processes. Karst is largely restricted to the most soluble rocks, which are salt (360,000 mg/liter), gypsum and anhydrite (2400 mg/liter), and limestone and dolostone (30–400 mg/liter). The numbers denote effective solubility in meteoric waters under standard conditions.
Being so soluble, salt is seen only in the driest places (for example, Death Valley, California), where it displays intensive dissolution topography. Surface gypsum karst is also comparatively rare in humid regions, but its dissolution at depth may produce widespread collapse and subsidence landforms (covered karst); it is often well developed in arid and semiarid areas such as the Pecos River valley of New Mexico. Pure limestones (CaCO<sub>3</sub>) are the principal karst rocks, hosting the greatest extent and variety of features. Dolostone (the double carbonate mineral, CaMg (CO<sub>3</sub>)<sub>2</sub>) is significantly less soluble: the type and scale of dissolutional forms developed in it is normally less than in limestone, giving rise to topographies that are transitional to fluvial (stream-derived) landscapes.
Industry:Science
Avian influenza or “bird flu” first made headlines in 1997, when the H5N1 virus caused an outbreak among poultry in Hong Kong. Within 3 days, Hong Kong's entire poultry population of 1.5 million birds was culled, and the outbreak was temporarily contained. The virus reappeared in Asia in December 2003. By 2004, several Southeast Asian countries were reporting outbreaks in poultry, and human cases were reported from Thailand and Vietnam.
Despite massive culling operations, the disease continued to spread and by July 2005 was reported in Siberia, Kazakhstan, Mongolia, and Croatia. The number of human cases also continued to rise. In addition, cases of fatal avian influenza were reported in civets, zoo leopards and tigers, and domestic cats—species that were not previously thought to be susceptible. In 2006, disease spread to several countries in Western Europe and appeared in Africa for the first time. The human case count has now exceeded 200 (as of September 2006), with mortality of approximately 50%.
The virus continues to mutate and evolve, and two distinct strains or clades have emerged—the original index strain that initiated the outbreak (Clade 1) and is circulating in Cambodia, Laos, Malaysia, Thailand, and Vietnam; and another strain (Clade 2) called the Indonesia strain that is circulating in Indonesia, China, Japan, and South Korea.
Industry:Science
Developmental dyslexia is characterized by unexpected difficulty in reading in children and adults who otherwise possess the intelligence and motivation considered necessary for accurate and fluent reading. Dyslexia is one of the most common problems affecting children and adults; in the United States, the prevalence of dyslexia is estimated to range from 5 to 17% of school-age children, with as many as 40% reading below grade level. It is the most common and most carefully studied of the learning disabilities, affecting at least 80% of all individuals identified as learning-disabled. Recent epidemiologic data indicate that, like hypertension and obesity, dyslexia fits a dimensional model—within the population, reading ability occurs along a continuum, with reading disability representing the tail of a normal distribution.
Good evidence based on sample surveys of randomly selected populations of children indicates that dyslexia affects boys and girls comparably. (The long-held belief that only boys suffer from dyslexia reflected bias in school-identified samples.) Dyslexia is a persistent, chronic condition that stays with the individual for a lifetime. It is both familial and heritable; about half of children who have a parent with dyslexia, as well as half of the siblings of dyslexics and half of the parents of dyslexics, may have the disorder.
Industry:Science
Deposits formed by rivers. An alluvial river is one which flows within its own fluvial sediments, as distinct from one that has incised into the underlying bedrock. A river accumulates deposits because its capacity to carry sediment has been exceeded, and some of the sediment load is deposited. Rivers tend toward a state of dynamic equilibrium, in which they adjust their slope in response to changes in discharge and sediment load. The result is a channel profile that is steep in its source areas but flattens out downstream, and is graded to a slope of zero where the river discharges into a lake or the sea.
Fluvial sedimentary accumulations range from temporary bars deposited on the insides of meander bends as a result of a loss of transport energy within a local eddy, to deposits tens to hundreds of meters thick formed within major valleys or on coastal plains as a result of the response of rivers to a long-term rise in base level or to the uplift of sediment source areas relative to the alluvial plain. Both these processes perturb the graded profile so that it tends to rise, creating space, or accommodation, for sediment. The same processes control the style of rivers and the range of deposits that are formed, so that a study of the deposits may enable the geologist to reconstruct the changes in controlling factors during the accumulation of the deposits.
Industry:Science
Any of six naturally occurring minerals characterized by being extremely fibrous (asbestiform), incombustible, and having high tensile strength. Historically they were utilized in commerce for fire protection; for fiber reinforcing material in tiles, plastics, and cements; for friction materials; and for thousands of other uses. Currently the vast majority of asbestos used worldwide is chrysotile type which is used for asbestos-cement production, while use continues to be strong only in friction products, coating and compounds, and roofing products.
Because of great concern over the health effects of asbestos, many countries have promulgated strict regulations or bans on its use. The six minerals designated as asbestos also occur in a nonfibrous form. In addition, there are many other minerals which occasionally occur naturally with a highly fibrous morphology similar to asbestos. These ambiguities generated a controversy over whether the mineralogical definition of asbestos fibers should be applied when doing health hazard evaluations for legal and regulatory purposes. The U.S. Occupational Safety and Health Administration (OSHA) has reviewed this matter and concluded that the medical and scientific information available does not support an expansion of the definition of asbestos to include minerals not mineralogically defined as asbestos in the regulations.
Industry:Science
For a manufacturing system to achieve its maximum performance, the operations of its subsystem, including machines and personnel, as well as the flow of parts and products, should be well coordinated; this requires proper scheduling of the operations and flows. For example, if many parts are waiting to be processed by a certain machine, a decision must be made as to which part should be processed next when the machine finishes the current processing (job dispatching problem).
When there are several machines capable of performing the same job, a machine must be selected for the task (machine selection problem). For a longer time scale, it is necessary to schedule when and how many of each product should be produced. The results of these decisions must satisfy certain production requirements. For example, the total time required to produce a certain number of products; the production delay from the due date (the time when each product should be completed); and the cost required for the personnel, machines, or inventory ideally should be minimized.
In the recent trend for designing more flexible manufacturing systems, more and more decision-making points are introduced in order to deal with the demands for producing a large variety of products in small amounts and in frequently changing environments, where the proper scheduling plays an even more essential role.
Industry:Science
Bone is formed by cells called osteoblasts, which arise from progenitor cells in a multistep process. At bone defect (injury) sites, osteoblast progenitors are recruited from thin cell layers surrounding the bone surface and tissue inside the bone (periosteum and bone marrow, respectively). That is, resected or injured bone sites induce the chemoattraction of multipotent progenitor cells that originally reside in the marrow or periosteum, and these cells become osteoblasts at the defect site through a series of controlled differentiation steps. These progenitor cells are referred to as stromal or mesenchymal stem cells (MSCs).
When metals or their alloys are implanted at bone defect sites, corrosion may inhibit the differentiation of MSCs around the implanted metals, resulting in encapsulation of the implants by scar tissue or a fibrous membrane, with the thickness of the membrane proportional to the degree of metallic corrosion. In contrast, when alumina (Al<sub>2</sub>O<sub>3</sub>) ceramics or titanium devices are implanted into bone defects, the MSCs around the ceramics can undergo osteogenic differentiation. This results in functional regeneration of the bone tissue around the materials with minimal scar tissue or fibrous membrane formation. Still, the interface between the bone and the implant is not strong, and will detach easily upon shear and load stress.
Industry:Science
Approaches to understanding the mechanical processes shaping river channels have historically been limited by the challenge of collecting data capable of delineating the complexity reflected in the fluid flow of water. At the same time, accurately capturing this complexity is critical for research in the fields of fluvial geomorphology, hydrology, and environmental engineering.
The study of fluid dynamics within the context of river environments reveals that fundamental properties, such as velocity, are highly variable over small spatial and temporal scales. The characteristics and behavior of flowing water determine how streams influence environments, such as the shape and structure of the channel, the erosive power exerted by the water, and the amount and character of the materials the river can transport. At watershed scales, time-averaged measurements of velocity in the downstream direction may provide reasonable estimates of reach-averaged stream power and the ability of the flowing water to perform mechanical work. However, where there is a need for higher-resolution measures of velocity and stream power to calculate bed shear stress or stream competence, define hydraulic microhabitat conditions, or generate deterministic models of stream channel adjustment, small-scale variations in the directionality and magnitude of flow vectors should be taken into account.
Industry:Science
