.... so infinitesimal that billions could fit into a drop of water---or a drop of human blood. Viruses have the most exquisite ability to sense the right cell surfaces. They don't just cause diseases in people, they infect every form of life on earth. Some emerging viruses are very serious. Common examples are the viruses, B and C. The B pattern of illness was recognized at the end of the nineteenth century, yet the virus itself was not isolated until 1963. One hundred and seventy six million people are carrying the surface antigen of this one virus globally, and the infection causes a vast amount of illness and death, including most of the fatal .....

.... that they may be a separate species. The Borneo male has relatively large cheek pads, a tremendous laryngeal sac and a square shaped face. The Sumatran male has small pads and laryngeal sac, a ginger coloured moustache, a pronounced beard, and a diamond shaped face. Individuals can also be distinguished chromosomally, biochemically, and by their cranial characteristics. There is a great deal of individual variety in the orangutan. "Each orang-utan had a distinct personality and in dealing with such highly intelligent animals in captivity, the keeper's knowledge of the individual was probably more important than the knowledge of the overall beha .....

.... today and is a major cause for concern. The discovery of penicillin the 1940s proved to be the dawn of the antibiotic era. In less than two decades, major advancements had been made in the development of antibiotics. There were so many different antibiotics developed that doctors and scientists focused their attention on other problems plaguing the nation. Doctors prescribed antibiotics frequently, often when they were not even needed. According to a 1998 report by the Institute of Medicine, up to fifty percent of antibiotics are prescribed unnecessarily. This blatant overuse of antibiotics had a profound effect on the efficiency of the dru .....

.... composition of industries (for examples, Berman, Bound and Griliches, 1994). The results of these studies are consistent with those of the case studies and the hypotheses that the recent technological change has shifted the relative demand for skilled labor to the right. Changes in production techniques have widened across the country quickly, especially the multinational firms. Thus, if technological change is an important determinant of relative demand shifts, one would expect to observe patterns in other industrialized countries similar to those in the United States. Some of the recent studies report results for a variety of old industrial .....

.... hand, have relatively constant body temperatures. Their body temperature is independent of that of their external environment. Monkeys and walruses, for example, both have body temperatures of about 38„aC, despite living in very different habitats. However if body temperature rises above its optimum level (usually around 40„aC in mammals) then the enzyme rate inside the body will go into sharp decline. This is because enzymes are proteins, and become denatured. One of the first organs to be affected is the brain. Since the brain controls breathing and the circulation, the rise in body temperature disrupts the normal functioning of these importa .....

.... view had done something great without looking into the possibilities of where this would lead. I believe Djerassi, similar to most scientists of his day, was so entranced by the excitement of synthesizing his product and achieving his goal that he did not stop to think of the ramifications of his accomplishment. The ethical dilemma was not explored before hand, and this to me is the great tragedy of most scientific discovery, since I firmly believe each scientist is responsible for that which he creates. Djerassi does confront a few questions of ethics and morality after the fact. On page 61, in chapter 6, he reflects on the argument of the u .....

.... when, among other people, Timothy Leary became interested in VR. This has also worried some of the researchers who are trying to create very real applications for medical, space, physical, chemical, and entertainment uses among other things. In order to create this alternate reality, however, you need to find ways to create the illusion of reality with a piece of machinery known as the computer. This is done with several computer-user interfaces used to simulate the senses. Among these, are stereoscopic glasses to make the simulated world look real, a 3D auditory display to give depth to sound, sensor lined gloves to simulate tactile feedback, .....

.... of pressure, and they could easily then be turned back into gas. CFCs were completely inert and not poisonous to humans. They became ideal solvents for industrial solutions and hospital sterilants. Another use found for them was to blow liquid plastic into various kinds of foams. In the 1930's, household insecticides were bulky and hard to use, so CFCs were created because they could be kept in liquid form and in an only slightly pressurized can. Thus, in 1947, the spray can was born, selling millions of cans each year. Insecticides were only the first application for CFC spray cans. They soon employed a number of products from deodorant to .....

.... though, you could make it escape the planet's gravity entirely. It would keep on rising forever. The speed with which you need to throw the rock in order that it just barely escapes the planet's gravity is called the "escape velocity." As you would expect, the escape velocity depends on the mass of the planet: if the planet is extremely massive, then its gravity is very strong, and the escape velocity is high. A lighter planet would have a smaller escape velocity. The escape velocity also depends on how far you are from the planet's center: the closer you are, the higher the escape velocity . The Earth's escape velocity is 11.2 kilometers per s .....

.... infected with Hiv eventually develop symptoms that also may be caused by another, less serious conditions. Some symptoms include enlarged lymph glands, tiredness, fever, loss of weight, diarrhea, and night sweats. AIDS is caused by two viruses that belong to a group called retroviruses. The virus became known as HIV-1. In 1985, scientists in France identified another closely related virus that produces AIDS. This such virus became known as HIV-2 and occurs mainly just in Africa. The virus,HIV-1 is spread throughout the world . HIV infects certain white blood cells, including T-helper cells and macrophages, that play key roles in the f .....