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Astigmatism is the most common vision problem. It may accompany nearsightedness or farsightedness. It is usually caused by an irregularly shaped cornea, but sometimes it is the result of an irregularly shaped lens. Either type can be corrected by eyeglasses, contact lenses, or refractive surgery.
About 80% of major fungal systemic infections are due to Candida albicans. Another form, Candida peritonitis, occurs most often in postoperative patients. A rare disease, Candida meningitis, may follow leukemia, kidney transplant, other immunosuppressed factors, or when suffering from Candida septicemia.
The Babylonians wrote numbers in a system that used 60 as the base value rather than the number 10. They did not have a symbol for "zero."
Many of the drugs used by neuroscientists are derived from toxic plants and venomous animals (such as snakes, spiders, snails, and puffer fish).
In the United States, there is a birth every 8 seconds, according to the U.S. Census Bureau's Population Clock.