Tuesday, November 11, 2014

   Gastritis is the acute or chronic inflammation of the mucous membrane that lines the stomach. Gastritis is characterized by nausea, vomiting, and cramp like pain and often by loss of appetite.
   Acute gastritis is a common form of upset stomach. It is usually caused by the consumption of irritating foods or liquids, particularly alcohol. These substances produce a mild temporary inflammation that is cured by avoiding the offending substance and by eating bland foods. If the condition results from prolonged use of alcohol, it may be chronic, as well as acute, and abstinence from alcohol is necessary to effect a cure.
   Severe cases of acute gastritis may be caused by the swallowing of acids, lyes, or other poisons. If the condition is not promptly treated, death may result.
   Chronic irritation, which may develop from acute gastritis or other disturbances in the intestinal tract, can cause thickening of the stomach lining or partial destruction of the lining. Chronic gastritis may lead to ulceration and other disorders of the stomach.

What is a gene?

Monday, November 10, 2014

   A gene is one of the units that determine the characteristics an organism inherits from its ancestors. Such inherited characteristics include height and the color of the skin, eyes, and hair. Some traits, such as a person's ability to curl his tongue, are determined by a single gene, and others, such as skin color, are determined by a combination of genes.
   Every cell has thousands of genes. They are located on the chromosomes, which are small thread like structures in the nucleus, and each gene occupies a specific place on a chromosome. The number of genes and the way in which they are arranged on the chromosomes are always the same in every member of a species.
   Since chromosomes usually occur in pairs, genes also are paired. The genes that have a similar location on each chromosome in a pair are called alleles. Alleles influence the same hereditary trait, but they may have a different effect on it. For example, the gene that produces short plants is an allele of the gene that produces tall plants. Each time a cell divides, every one of its genes makes a copy of itself. Occasionally a gene is changed in some way so that it has a different effect on a trait. Such a change in a gene is called a mutation. The original gene and the altered gene are alleles.
   Genes are too tiny to be seen, but biochemical studies have shown that they consist of nucleic acids combined with protein. It is believed that they exert their influence through the enzymes in cells. Each gene probably controls the synthesis of a specific protein. The protein, in turn, acts as an enzyme that makes possible a particular reaction in the cell. The reaction may be concerned with protein synthesis, growth, pigment formation, or any other activity in the cell.

What is Geometry?

Sunday, November 9, 2014

   Geometry is the branch of mathematics concerned with the properties and relationships of points, lines, surfaces, solids, and angles. Geometry may be thought of as the science of space. Indeed, just as arithmetic is used to deal with experiences involving the counting process, so geometry is used to describe and relate experiences that involve space.
   The fundamental ideas of geometry are suggested by everyday experiences. Thus, the experience of where an object is leads to the idea of an exact, fixed location. This is the intuitive idea to which the term "point" refers. Many physical objects suggest the idea of a point. Examples include the corner of a block, the tip of a pencil, or a dot on a sheet of paper. Such things are called models or representations or pictures of points, although they show only approximately the idea in mind. Similarly, the set of points suggested by a tightly stretched string, the edge of a desk, or a flagpole is called a line segment. The physical objects that suggest line segments are called models, or representations, of segments. If a segment is extended indefinitely in one direction, it is called a ray, and if extended indefinitely in both directions, it is called a line. Similarly, the word "plane" is used to describe a flat surface like a floor, desktop, or chalkboard, but it is imagined as extending indefinitely in all directions. This means that a plane has no edges just as a line has no ends.
   The study of geometric figures that lie in one plane is often called plane geometry. The study of figures not all in one plane may be called solid geometry. Frequently, however, no distinction is made, and plane geometry and solid geometry are studied together as parts of the same course.

What is a depressant?

A depressant is a drug that reduces the activity of various body functions. Some depressants such as anesthetics, sedatives, antiepileptics, narcotics analgesics, and some muscle relaxants, slow nervous and muscular activity by acting on the central nervous system. Tranquilizers are depressants that affect only part of the nervous system. They induce relaxation without causing total depression.

Facts about birthstones

Facts about birthstones
Did you know? The current assignation of stones to months was established in 1912