Vampire bats are common in Central and South America, where they feed on livestock and sometimes people. Michael & Patricia Fogden/Corbis hide caption

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Wanda Kaczynski and her son David Kaczynski (right background) are escorted to their car by defense lawyers after Unabomber Theodore Kaczynski pleaded guilty Jan. 22, 1998, in Sacramento, Calif. John G. Mabanglo/AFP/Getty Images hide caption

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The white arrows in these two tumor samples point to a subset of tumor cells that are in a resting state. Nature hide caption

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Contestants Marianne Baba (left), Lois Conway and Ruth Swenson stand next to plates of their X-Rays during a chiropractor-judged beauty contest. Wallace Kirkland/Time hide caption

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Health and Human Services Secretary Kathleen Sebelius joins Democratic senators at a news conference on Capitol Hill on Tuesday to announce new preventive health coverage for women that takes effect Wednesday. Win McNamee/Getty Images hide caption

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National Institute of Allergy and Infectious Diseases Director Dr. Anthony Fauci said a voluntary halt to bird flu research should stay in effect. Chip Somodevilla/Getty Images hide caption

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The Ebola virus causes a deadly form of hemorrhagic fever. Frederick Murphy/CDC hide caption

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Drivers under 25 are more likely to send text messages and make calls behind the wheel. They're also less able to handle distractions while driving. iStockphoto.com hide caption

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This photo provided by the U.S. Attorney's Office in New Hampshire shows David Kwiatkowski, a former lab technician at an Exeter, N.H., hospital. AP Photo/U.S. Attorney's Office hide caption

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CamelBak-brand water bottles on display at an outdoor supply store in Arcadia, Calif., in 2008. The company removed BPA from the plastic in its bottles. David McNew/Getty Images hide caption

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A government official in Bali, Indonesia, holds a chicken before administering an injection to cull it as a precautionary measure in April to prevent the spread of bird flu. Firdia Lisnawati/AP hide caption

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