.... though all subsequent biological effects can be traced back to the interaction of radiation with atoms, there are two mechanisms by which radiation ultimately affects cells. These two mechanisms are commonly called direct and indirect effects. If radiation interacts with the atoms of the DNA molecule, or some other cellular component critical to the survival of the cell, it is referred to as a direct effect. Such interaction may affect the ability of the cell to reproduce and, thus, survive. If enough atoms are affected in such a way that the chromosomes do not replicate properly, or there is a significant alteration in the information carried by the DNA .....

.... the human genome project is well underway and ahead of schedule. With this new knowledge comes worries, for humans, however. What if the information stored in our genes was available to the public? Would insurance companies and employers base their selections on these traits? Also, with the total knowledge of every sequence of every amino acid chain in a person's genome, couldn't a laboratory perceivably reconstruct an exact copy of, or clone, that person? These are all issues that will have to be dealt with in the near future, but for now we need only concern ourselves with the objective observation of these proteins in our attempt to explain our ever mys .....

.... up like a rope tied in knots. He termed the strange nerve bundles neurofibrillary tangles. He also noted an unexpected accumulation of cellular debris around the affected nerves, which he termed senile plaques. In a medical journal article published in 1905, Alzheimer speculated that the nerve tangles and plaques were responsible for the women’s dementia. Alzheimer’s disease is a disorder marked by a gradual decline in brain function that gets worse with time. It used to be assumed that this change was a normal part of aging that we called senility. Some people develop this condition when they are as young as 40 years of age. However, the disease i .....

.... and cardiovascular diseases, and more ultimately with respect to human health as a whole. Emphasis is given to the structure of the different forms of and how this affects the physical and chemical properties of each type resulting in different advantages and disadvantages to human health. The way in which fibre helps prevent disease is also discussed extensively in order to prove that clinical nutritionists are right to encourage intake of in increased amounts with caution to the fact that overindulgence may cause adverse effects. Lastly the importance of high fibre foods in conjunction with a healthy lifestyle is presented as the 'formula' for a healthy b .....

.... and 400, it doesn't tell one that the 1975 census was 1500. Therefore saying that the Bali tiger, theCaspian tiger, the Javan tiger, the Manchurian tiger, and the Southwest Chinese tiger are now extinct doesn't give you aportrait of the process of extinction. The Javan tiger became extinct in the 1970's in a set aside special national park under full protection. Politicans and bureaucrats seem to be obsessed with numbers and not trends. Let me illustrate this with tigers. There are frequently requests as to the exact number of tigers, or a tiger subspecies left in the world. That tells you that there are people that care. But there are so little ti .....

.... its form in space is a gas). Hydrogen can do just about everything conventional fuels can do but better. Hydrogen can be "packaged" in several ways, as a fuel gas in a H2/02 powered engine or the newly devised solid state pellet of hydrogen isotopes that contains about the equivalent of 5000 cubic feet of hydrogen and is broken down and releases gas into the second chamber where it goes to the engine for use. There are many ways to get pure hydrogen out of many compounds using methods such as electrolysis and chemical reactions. One of the easiest ways is using a chemical reaction. Simple chemicals (aluminum,sodium hydroxide, and water) can be reacted in the .....

.... the sex chromosomes. The person with is a male who, because of this chromosome variation, has a hormone imbalance. While Dr. Harry Klinefelter accurately described this condition in 1942, it was not until 1956 that other researchers reported that many boys with this description had 47 chromosomes in each cell of their bodies instead of the usual number of 46. This extra sex (X) chromosome causes the distinctive make-up of these boys. All men have one X chromosome and one Y chromosome, but sometimes a variation will result in a male with an extra X. This is and is often written as 47,XXY. There are other, less common variations such as 48,XXYY; 48,XXXY; 49 .....

.... well as the lungs or gills of the early tetrapod fossils. This information is critical in understanding the history and the process of growth and change. It aids in learning about human evolution. Background: Tetrapods are creatures with four limbs, hips, shoulders, fingers, and toes, which developed sometime after lobe-finned fish, and before the first fully terrestrial vertebrates. The earliest tetrapod known is Acanthostega. It is also considered the most primitive tetrapod. It is very close to its fish ancestry, but still anatomically far from its terrestrial relatives. These creatures still lived in water, but they had a lot of the terrestrial tetrapod an .....