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Author Question: When considering a possible research problem, certain ideas may be taken for granted without ... (Read 26 times) |
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.
Many people have small pouches in their colons that bulge outward through weak spots. Each pouch is called a diverticulum. About 10% of Americans older than age 40 years have diverticulosis, which, when the pouches become infected or inflamed, is called diverticulitis. The main cause of diverticular disease is a low-fiber diet.
In 1835 it was discovered that a disease of silkworms known as muscardine could be transferred from one silkworm to another, and was caused by a fungus.
To prove that stomach ulcers were caused by bacteria and not by stress, a researcher consumed an entire laboratory beaker full of bacterial culture. After this, he did indeed develop stomach ulcers, and won the Nobel Prize for his discovery.
In 2012, nearly 24 milliion Americans, aged 12 and older, had abused an illicit drug, according to the National Institute on Drug Abuse (NIDA).