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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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 cross-sectional X-ray shows what's called a "sunken chest." The bright circle near the bottom is the spine; the gray blob on the right is the heart. Living LLC/Getty Images hide caption

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Dr. Lisa Sterman holds Truvada pills at her office in San Francisco. The drug was recently approved by the Food and Drug Administration to prevent infection in people at high risk of infection with HIV. The pill, already used to treat people with HIV, also helps reduce the odds they will spread the virus. Jeff Chiu/AP hide caption

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Pedestrians walk past a medical marijuana dispensary in the Echo Park area of Los Angeles Tuesday. The City Council voted that day to ban marijuana shops outright. Damian Dovarganes/AP hide caption

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Timothy Ray Brown, shown in May 2011 with his dog Jack in San Francisco, is the only man ever known to have been fully cured from AIDS. Brown is known as the "Berlin patient" because he had a bone marrow transplant in a German hospital five years ago. Eric Risberg/AP hide caption

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A mobile clinic set up to test students for HIV is parked near Madwaleni High School in Mtubatuba, KwaZulu-Natal, South Africa on March 8, 2011. Parts of the South African province have HIV rates that are more than twice the national average. Stephane de Sakutin/AFP/Getty Images hide caption

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Beth Israel Deaconess Medical Center has higher rates of readmissions for Medicare patients for some conditions. But its mortality rates for the same conditions is lower than at many hospitals. Beth Israel Deaconess Medical Center hide caption

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Chickens are under quarantine in Tepatitlan, Jalisco State, Mexico. The Mexican government declared a national animal health emergency July 2 in the face of an aggressive bird flu epidemic that has infected nearly 1.7 million poultry. Hector Guerrero/AFP/Getty Images hide caption

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HIV patient Darnell Hollie, 47, talks to her doctor Monica Gandhi (right) at San Francisco General Hospital. Her path from drug addict to model patient was "a lot of work, but if you want it, it's there for you," Hollie says. Richard Knox/NPR hide caption

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