.... resistance to corrosion, readiness to form alloys and chemical compounds, and ease of recycling. Its versatility, as well as its physical and chemical properties, accounted for its extensive use. Lead can be rolled into sheets which can be made into rods and pipes. It can also be molded into containers and mixed with other metallic elements. Lead was used in ancient times for making coinage, art objects and water pipes. One of the first known toxic substances, lead was used by the Romans for lining aqueducts and in glazes on containers used for food and wine storage; and it is suspected to have resulted in widespread lead poisoning. Membe .....

.... para la instalación de redes en sus computadoras, un proceso costoso y que lleva tiempo de realizar, convirtiéndose en mucho más difícil cuando las oficinas de la compañía se encuentran repartidas por todo del mundo. Incluso en las mejores condiciones, el compartir información entre programas, formatos de archivo y plataformas diferentes no es una tarea sencilla. Por medio de la misma tecnología que se aplica a Internet, las intranets solucionan este problema, consiguiendo que las comunicaciones y colaboraciones internas sean mucho más sencillas. Las intranets usan TCP/IP para transmitir información a través de la re .....

.... our past. These tangible remains help us understand other cultures, appreciate architecture and engineering, and learn about past accomplishments. Furthermore, they offer educational and recreational opportunities and provide links to our past. People have lived in North America for at least 12,000 years. Archaeologists and historians have divided this time span into prehistoric and historic periods. The prehistoric period extends from the earliest arrival of humans in North America to the coming of the European explorers. The historic period begins with the arrival of these explorers and continues up to the present. As you walk across .....

.... of the scarcity of alcohol. Prohibition was repealed after just thirteen years while the prohibition against marijuana lasted for more than seventy five years. This double standard may have resulted from the wishes of those in power. Alcohol prohibition struck directly at tens of millions of Americans of all ages, including many of societies most powerful members. Marijuana prohibition threatened far fewer Americans, and they had relatively little influence in the districts of power. Only the prohibition of marijuana, which some sixty million Americans have violated since 1965 has come close to approximating the prohibition experience, b .....

.... backbones.) These animals are further broken down into phylums and classes. ECHINODERMS Echinoderms are marine invertebrate animals of the phylum Echinodrmata, having external skeletons of calcareous plates just under the skin, no head, and a water vascular-system with tube feet. Echinoderms are radially symmetrical, lack specialized ecretory organs, and reproduce sexually. Echinoderms have the ability to regenerate lost or injured body parts. Starfish: Starfishes are free-living echinoderms that have a flat, star-shaped or pentagonal body, usually with a continuous disc that has five or more ray-like extensions called arms. Tube fe .....

.... the circulatory system, blood is pumped by the heart in a tube to the aorta, the head, and to other organs then enters the ostia openings along the sides of the tube back to the heart. The respiratory systems carries O2 to cells and takes away CO2 from cells through branching out to call cells of body. The nervous system consists of a brain receiving information from eyes, antennae, and controls the whole body and 2 nerve cords containing ganglia fused together to control activities of the segment without the help of the brain. insect muscular system is made up of a few thousand samll but string muscles allowing the insect to carry objects h .....

.... argue that we have entered post modernity or post Fordism, a new age technological revolution, which profoundly effects social structure and values. Some issues that will be addressed are: elimination of work in the traditional sense, longevity, early retirement, the elimination of cash, the restructuring of education, industry and a movement to global politics, economics and world government. In particular this paper will suggest that the Christian Judao work ethic with society’s goals of full employment in the traditional sense is no longer appropriate, necessary or even possible in the near future, and that the definition of work .....

.... public-policy and public-health problems worldwide. COSTS I think that the AIDS epidemic is having a profound impact on many aspects of medicine and health care. The U.S. Public Health Service estimates that in 1993, the lifetime cost of treating a person with AIDS from infection to death is approximately $119,000. Outpatient care, including medication, visits to doctors, home health aids, and long-term care, accounted for approximately 32 percent of the total cost. Persons exposed to may have difficulty in obtaining adequate health-insurance coverage. Yearly AZT expenses can average approximately $6,000, although in 1989 the drug's ma .....

.... drop 98%. In '74 the agency required drinking water to be physically and chemically treated. CFCs were banned in '78 and a nation-wide toxic waste site cleanup program was developed in 1980. The EPA then evacuated Times Beach, Montana for dangerous levels of dioxin in soil, which was then criticized for its heavyhandedness and arrogance. Charges of mismanagement and undue political influence caused the head of the EPA to resign in '83. "The deputy director resigns because of charges of making a 'hit list' of employees to be hired, fired, or promoted because of political leanings. The former head of the toxic waste cleanup is found g .....

.... able to develop the Proton Exchange Membrane (PEM) to produce nearly ten times as much energy, while being only a fraction of the size. How the PEM Works: A is an electrochemical device that produces electricity silently, without combustion. Hydrogen fuel, which is one of the most abundant chemicals in the universe, and oxygen from the air are electrochemically combined in the to produce electricity. Heat and pure water vapour are the only by-products of the . The Ballard Fuel Cell is made up of two electrodes, the anode and the cathode, separated by a polymer membrane electrolyte. Both the anode and the cathode are coated in a thin .....