... be lifelong in all who become infected. People 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 macropha ...

... geothermal energy not only contributes to our energy supply, but also reduces energy demand (through the use of geothermal pumps to heat and cool buildings, reducing the need for natural gas and other nonrenewable resources). It is unfortunate that only a small part of our geothermal resources are being used today. Hot water, at temperatures between 300 and 700 degrees Fahrenheit, is brought from an underground reservoir to the surface and is converted to steam by using changes in pressure. The steam and liquid are separated, with the steam turning turbines (generating electricity) and the water is injected back into the reservoir to maintain the chamber's pr ...

... produced from automobile engines have greatly intensified the problem. Winds can carry the pollutants thousands of kilometers away from their source. The British government has recognized that sulfur emissions from power plants in the United Kingdom are contributing to acid deposition in Scandinavia. Canadian emissions contribute substantially to in the northeastern United States, for example, and much of the sulfur falling in eastern Canada is believed to originate in the United States. In 1986 the U.S. National Academy of Sciences acknowledged that from U.S. sources had become a serious problem in the eastern United States and Canada. Although the Canadian ...

... to support these claims of human and wildlife harm is largely from laboratory studies in which large doses are fed to test animals, usually rats or mice, and field studies of wildlife species that have been exposed to the chemicals mentioned above. In laboratory studies, high doses are required to give weak hormone activity. These doses are not likely to be encountered in the environment. However the process of bioaccumulation can result in top-level predators such as humans to have contaminants at levels many million times greater than the environmental background levels (Guilette 1994). In field studies, toxicity caused by endocrine disruption has been associ ...

... of the NH2 group and the acidic properties of the COOH group. The amine group (NH2) is Lewis base because it has a lone electron pair which makes it susceptible to a coordinate covalent bond with a hydrogen ion. Also, the carboxylic group is a Lewis acidic because it is able to donate a hydrogen ion (Kotz et al., 1996). Other forms of amino acids also exist. Amino acids may exists as acidic or basic salts. For example, if the glycine reacted with HCl, the resulting amino acid would be glycine hydrochloride (see fig. 2). Glycine hydrochloride is an example of an acidic salt form of the amino acid. Likewise, if NaOH were added, the resulting amino acid would ...

... due to the fact that “it directly examines the genetic information, DNA.” Furthermore, if there is a gene that influences an individual's sexual orientation, there is a great possibility of that trait being passed down from generation to generation. Experiments conducted led to the possible conclusion that the region Xq28 carries a gene influencing male sexual orientation. However, there are a few flaws to their interpretation of the results. Among them are stated in the article. A replication of the experiment is necessary, the separation of the particular gene has not been achieved, and the importance of the region has not yet been determined. Moreover, t ...

... warp and a white cotton filling (Groilers, 1996). The thermal underwear is duofold, with an outer layer made of 65% cotton, 25% wool, and 10% nylon, and an inner layer made of 100% cotton. It's the winter again and the weather is becoming colder. Each morning many people wonder what to wear to stay as warm as possible, but they aren't sure which material will keep them warmest. The experiment was chosen to see which clothing insulator retains the most heat. "Insulation is material that protects against heat, cold, electricity, or sound." (Science Encyclopedia, 1984). In this case the insulation will be protecting against a cold temperature. The hyp ...

... has been hiding for 50 years? The answer is Area 51. Area 51 was built in the 1950's by the CIA as a top secret area of defense. It was the testing grounds for such war planes as the Aurora Project, SK-71 Blackbird, and the F-117a Stealth fighter spy plane (Misage 15). According to many Americans, these are not the only flying machinery which exists in Area 51. On July 7, 1947, two ranchers in Roswell, New Mexico, observed something that would be the beginning of what might be one of mankind's most unexplained phenomenons in history. According to these ranchers, (who asked to be anonymous) a flying object came out of the South East and went flying into the Nor ...

... in London founded a century ago. Scientists have run thousands of experiments to learn if minds indeed have supernatural powers. Most tests investigated one of the three main "faculties": telepathy, clairvoyance and precognition, collectively called extrasensory perseption (ESP) by American psycologist J.B. Rhine. Dating from the early 1930s, Rhine's tests at Duke University at Durham, North Carolina, remain the most quoted examples of an expirimental blitzkreig on problems of parapsychology. Three years of Rhine's telepathy and clairvoyance testing averaged 7 successes out of every 25 people tested, 2 better than chance would have produced, an ...

... there are several different methods of birth control. The first that I am going to talk about is called the rhythm method. As its synonym implies, this method is based on the assumption that, for each women, there is a rhythmic pattern of menstruation and ovulation that can be identified by keeping a careful record of the dates of menstruation. A second assumption is that ovulation occurs 14 days before the onset of the next menstruation. The rhythm method is the most commonly used of the natural methods. To be used successfully a record should be kept for at least six menstrual cycles. The fertile period is then defined by a set of rules for example: The len ...