This undated X-ray image from the Cleveland Clinic shows electrodes implanted in a patient's brain. The method, known as deep brain stimulation, has traditionally been used to treat diseases such as Parkinson's, but new research indicates it could be helpful for patients with obsessive-compulsive disorder. AP hide caption

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James Kennedy, an amateur collector, found this fossilized bone with a mammoth or mastodon engraving in Vero Beach, Fla. It has been identified as one of the oldest pieces of prehistoric art in the Western Hemisphere Chip Clark/Journal of Archaeological Science hide caption

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Bottles of antiretroviral drug Truvada, a medicine used in trials that showed a reduction in transmission of HIV between heterosexuals. Justin Sullivan/Getty Images hide caption

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Dr. Donald Brown, left, gives 14-year-old Kelly Kent a dose of Gardasil, a vaccine for the human papillomavirus in 2006. The group that advises the U.S. government on vaccination recommendations is now starting to take costs for vaccines like Gardasil into consideration as vaccine prices rise. Charles Rex Arbogast/AP hide caption

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