A French man holds a flare during a protest against the government's austerity measures on Tuesday in Lille, northern France. European governments are proposing austerity measures, but critics say there should also be a plan for economic growth. Philippe Huguen/AFP/Getty Images hide caption

This image, from a sensor at the particle accelerator at CERN, is an example of the data signature a Higgs particle might generate. Researchers will spend 2012 sifting through data in an attempt to find the Higgs. CERN hide caption

Staff Sgt. Joshua White (center), Command Sgt. Maj. John Troxell (left) and Brigade Sgt. Maj. Mike Boom (right) observe a joint patrol of U.S. Army and Afghan National Army soldiers and Afghan police in Paktika province, Afghanistan, on Oct. 3. The mountainous border between Afghanistan and Pakistan has become a new front line in the Afghan war. Matt Ford/AP hide caption

Srdja Popovic, who runs the Center for Applied Nonviolent Action and Strategies, speaks in Belgrade in February. He played a prominent role in ousting Serbia's dictator in 2000, and has worked with Arabs involved in uprisings in their countries during the past year. Darko Vojinovic/AP hide caption

Choreographer Bill T. Jones at an appearance earlier this year. Frederick M. Brown/Getty Images hide caption

Vice President Joe Biden is interviewed by NPR's Robert Siegel in the Secretary of War Suite of the Eisenhower Executive Office Building, Dec. 13. David Lienemann/The White House hide caption

A day after leaving Iraq last week, U.S. Army soldiers from the 1st Cavalry Division lined up their armored vehicles near Kuwait City, Kuwait. Armored equipment will not stay behind after troops leave Iraq, but other property may. Joe Raedle/Getty Images hide caption

Former Pennsylvania Sen. Rick Santorum speaks Tuesday at the Lincoln Cafe in Belle Plaine, Iowa. Among GOP candidates, Santorum had the state to himself on Tuesday. Chris Carlson/Associated Press hide caption

Savannah Davis, 16, of Lufkin, Texas, poses on the Wellspring campus. Travis Dove/for NPR hide caption