A polar bear makes its way across the ice in Canada's Northwest Passage. Melting ice in the Arctic will make survival increasingly difficult for wildlife in the region. Jackie Northam/NPR hide caption

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A new study finds that when applying for scientific research grants from the National Institutes of Health, white researchers succeeded 25 percent of the time, while blacks about 15 percent of the time. Above, the Mark O. Hatfield Clinical Research Center at the NIH Campus in Bethesda, Md. NIH hide caption

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White pox disease on a frond of the endangered elkhorn coral on Carysfort Reef in the Florida Keys. The bacteria are overlying the coral tissue, exposing the coral's white limestone skeleton underneath. James W. Porter/University of Georgia hide caption

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The move by Micronesian islands to create a shark sanctuary two-thirds the size of the U.S. is the latest in a series of shark preservation areas aimed at reviving declining populations. Above, a group of hammerhead sharks swim in the Pacific Ocean off the coast of Malpelo in this undated photo. Yves Lefebre/AP hide caption

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Engineers at the Grand Gulf Nuclear Generating Station in Mississippi practice disaster and emergency situations in a mock-up control room. Every nuclear plant in the U.S. has control room simulators that are nearly exact replicas of the real facilities. Richard Harris/NPR hide caption

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Workers at the Fukushima Dai-ichi nuclear power plant spray a substance to help reduce dust on April 1. Experts say it's likely that workers at the plant could have reduced the severity of the accident if they had made different decisions during the crisis. TEPCO hide caption

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This March 24 aerial photo shows the extent of damage at the Fukushima Dai-ichi nuclear power plant in Japan. The 40-foot-tall tsunami destroyed the electrical and cooling systems, resulting in meltdowns at some of the reactors. Air Photo Service/AP hide caption

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The snowpack in the Rocky Mountains has been gradually thinning over the past century. Using tree ring measurements from subalpine larch trees like these in the Lake Chelan Wilderness in Washington state, researchers were able to put the Rocky Mountain data in long-term historical context. Jeremy S. Littell/UW Climate Impacts Group hide caption

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Shoppers crowd a narrow street outside Tsukiji market in Tokyo on Dec. 31, 2010. Japan has relatively tight social rules. And that makes sense, according to researchers. When people are squeezed together, they have an incentive to cooperate. Toru Yamanaka/AFP/Getty Images hide caption

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A worker checks the status of the water level at the Unit 1 reactor at the Fukushima Dai-ichi nuclear power plant in Japan on Tuesday. Japanese officials said the reactor doesn't appear to be holding water, which means its core probably sustained more damage than originally thought. TEPCO/AP hide caption

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