Democratic U.S. Sen. Mary Landrieu of Louisiana walks through the U.S. Capitol on Wednesday. Congress returned to work following last week's midterm elections break. Landrieu is locked in a runoff with Republican Rep. Bill Cassidy. Mark Wilson/Getty Images hide caption

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Beacon Power President and CEO Barry Brits, at the company's plant in Hazle Township, Pa. He says a loan from the Department of Energy made it possible for his company to develop its flywheel energy storage technology. Jeff Brady/NPR hide caption

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Few police departments have required officers to wear body cameras, but that's changing after the events in Ferguson, Mo., this summer. Jim Mone/AP hide caption

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Workers assemble Volkswagen Passat sedans at the German automaker's plant in Chattanooga, Tenn., on June 12, 2013. The automaker announced a new policy Wednesday that would allow interaction with labor unions at the plant. Erik Schelzig/AP hide caption

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This photo of Roy Middleton working underground at the Kentucky Darby mine now sits on the mantel in the Middleton home in Harlan County, Ky. He was killed after an explosion in 2006. Anna Boiko-Weyrauch/NPR/Original photo courtesy of the Middleton family hide caption

itoggle caption Anna Boiko-Weyrauch/NPR/Original photo courtesy of the Middleton family

Jay Ruskey grows coffee next to avocados on his farm, Good Land Organics, in Goleta, Calif. The two crops are often grown together in Central America, partly because they can share fertilizer and water. Lisa Morehouse/KQED hide caption

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Chinese President Xi Jinping and President Obama, seen here during a ceremony at the Great Hall of the People in Beijing, announced pledges to reduce greenhouse gases. HUANG JINGWEN/Xinhua /Landov hide caption

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Andy Warhol's Triple Elvis [Ferus Type] is set to be auctioned at Christie's, and expectations are high — but Warhol's estate won't see any of the money. Christie's Images LTD. 2014 hide caption

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An international tariff on high-tech goods could be rewritten, thanks to negotiations in China. Here, men use smartphones in Beijing last month, days after Apple released its iPhone 6 in the Chinese market. GREG BAKER/AFP/Getty Images hide caption

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A Malaysian flag sits on a table among other flags during a news conference at the Trans-Pacific Partnership Free Trade Agreement talks in July 2012 in San Diego. Nearly two and a half years later, the deal remains incomplete. Gregory Bull/AP hide caption

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