Mexico's President Felipe Calderon (left) starts a wind turbine that will help power the United Nations Climate Change Conference in Cancun. Officials will spend the next two weeks debating how to mobilize money to cope with climate change as temperatures climb, ice melts and seas rise. Israel Leal/AP hide caption

itoggle caption Israel Leal/AP

The deep-water-research submarine Alvin is launched from Atlantis. Scientists are studying how ecosystems in the Gulf of Mexico may have been affected by the Deepwater Horizon oil spill. Richard Harris/NPR hide caption

itoggle caption Richard Harris/NPR

Megan Lindsey (right) and her friend Alexandria Bodfish at soccer camp at University of Notre Dame.  Megan, 14, suffered concussions twice this fall while playing soccer. Courtesy of Barbara Wirtz hide caption

itoggle caption Courtesy of Barbara Wirtz

Cycling has at least tripled over the past two decades in several big cities across the U.S., including Minneapolis, Chicago and San Francisco. Jonathan Steinberg hide caption

itoggle caption Jonathan Steinberg

A hybrid solarized gas turbine power station owned by AORA Solar, a new Israeli company pushing solar hybrid technology, sits in the southern Israeli kibbutz of Samar. David Buimovitch/AFP/Getty Images hide caption

itoggle caption David Buimovitch/AFP/Getty Images

Dr. Barry Gordon, a neurologist and an experimental psychologist at Johns Hopkins University in Baltimore, has been trying to help his son Alex find language. Alex, pictured here at 7 years was always non-verbal and diagnosed as autistic at age 4. Courtesy of the Gordon Family hide caption

itoggle caption Courtesy of the Gordon Family

Eat Up: Eating a large meal at the holidays won't have a big impact on your weight, says one physiologist. That's because your brain keeps a close watch on food intake and can tolerate the occasional big meal. It's slow, steady weight gain that's more problematic. iStockphoto.com hide caption

itoggle caption iStockphoto.com