President Obama hugs NASA astronaut Mark Kelly, husband of Rep. Gabrielle Giffords, during a ceremony last week in Tucson, Ariz. Jewel Samad/AFP/Getty Images hide caption

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Emergency personnel work on Jan 8 at the scene where Rep. Gabrielle Giffords, (D-AZ) and others were shot outside a Safeway grocery store in Tucson, Ariz. Nearly anyone at the scene that day will be at risk for post traumatic stress disorder, but it's difficult to predict who will be affected. Matt York/AP hide caption

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Pronghorn antelope cross a rural Wyoming road south of Rock Springs, near a Bureau of Land Management lease sale challenged by the Wyoming Wildlife Federation. Jeff Brady/NPR hide caption

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The drilling operation at the Doyon Rig 19 at the Conoco-Phillips Carbon location in the National Petroleum Reserve, Alaska. The federal government is working on a plan to guide future drilling in the reserve, but environmental groups want some of the reserve set aside as wilderness. Judy Patrick/AP hide caption

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Shell's Nanuq was built especially for oil spill response cleanup in the Arctic Ocean. It can store 12,000 barrels of recovered oil. The 300-foot vessel is docked at Dutch Harbor, Alaska, for the winter. Jeff Brady/NPR hide caption

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