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The first documented use of surgical anesthesia in the United States was in Connecticut in 1844.
For about 100 years, scientists thought that peptic ulcers were caused by stress, spicy food, and alcohol. Later, researchers added stomach acid to the list of causes and began treating ulcers with antacids. Now it is known that peptic ulcers are predominantly caused by Helicobacter pylori, a spiral-shaped bacterium that normally exist in the stomach.
Looking at the sun may not only cause headache and distort your vision temporarily, but it can also cause permanent eye damage. Any exposure to sunlight adds to the cumulative effects of ultraviolet (UV) radiation on your eyes. UV exposure has been linked to eye disorders such as macular degeneration, solar retinitis, and corneal dystrophies.
Always store hazardous household chemicals in their original containers out of reach of children. These include bleach, paint, strippers and products containing turpentine, garden chemicals, oven cleaners, fondue fuels, nail polish, and nail polish remover.
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."
![Model of a longitudinal study in which 983 students were surveyed in 1984 and then again in 1985, 19](https://biology-forums.com/gallery/47/medium_6_31_05_15_8_20_42_219721459.jpeg)
![Model of a sequential study in which two cohorts were followed beginning at age 20. One cohort was f](https://biology-forums.com/gallery/47/medium_6_31_05_15_8_20_42_21974458.jpeg)