Alopecia areata is a type of hair loss that occurs when the immune system mistakenly attacks hair follicles, place where the hair growth begins. The damage to the follicle is usually not permanent. But the cause of the immune system attacks the follicles is unknown. Alopecia areata is most common in people younger than 20, but children and adults of any age may be affected. Women and men are affected equally. Alopecia areata usually begins when clumps of hair fall out, resulting in totally smooth, round hairless patches on the scalp. In some cases the hair may become thinner without noticeable patches of baldness, or it may grow and break off, leaving short stubs. In some rare cases, complete loss of scalp hair and body hair occurs. The hair loss often comes and goes but, hair will grow back over several months in one area but will fall out in another area. When alopecia areata results in patches of hair loss, the hair usually grows back in a few months. Although the new hair is usually the same color and texture as the rest of the hair, it sometimes is fine and white. About 10% of people with this condition may never regrow hair.
High-impact journals are those considered to be highly influential in their respective fields. The impact factor of journal provides quantitative assessment tool for grading, evaluating, sorting and comparing journals of similar kind. It reflects the average number of citations to recent articles published in science and social science journals in a particular year or period, and is frequently used as a proxy for the relative importance of a journal within its field. It is first devised by Eugene Garfield, the founder of the Institute for Scientific Information. The impact factor of a journal is evaluated by dividing the number of current year citations to the source items published in that journal during the previous two years.
Last date updated on June, 2014