The cruise ship Carnival Magic floats behind a catamaran off Cozumel, Mexico on Oct. 17. The ship skipped a planned stop there Friday, the cruise line says, after Mexican authorities delayed granting permission to dock. Reuters/Landov hide caption

itoggle caption Reuters/Landov

Rocky Juarez of the U.S. gets punched in the face in July 2010 by Jorge Linares of Venezuela during their WBA Fedelatin lightweight title fight in Las Vegas. Some researchers believe the human face evolved to take punches — without, of course, the boxing gloves. Steve Marcus/Reuters/Corbis hide caption

itoggle caption Steve Marcus/Reuters/Corbis

Avian influenza, or bird flu, causes an infectious and contagious respiratory disease. In the lab, several scientists have made the H5N1 strain more contagious, a controversial line of research. James Cavallini/ScienceSource hide caption

itoggle caption James Cavallini/ScienceSource

One rationale for extending Medicaid coverage to more people is to help them get to a doctor or clinic before a minor illness becomes a medical emergency. iStockphoto hide caption

itoggle caption iStockphoto

Researchers say there's plenty the beef industry can do to use less land and water and emit fewer greenhouse gas emissions. But producers may need to charge a premium to make those changes. iStockphoto.com hide caption

itoggle caption iStockphoto.com

Corn farmer Jerry McCulley sprays the weedkiller glyphosate across his cornfield in Auburn, Ill., in 2010. An increasing number of weeds have now evolved resistance to the chemical. Seth Perlman/AP hide caption

itoggle caption Seth Perlman/AP

Isabella Beukes, of Santa Rosa, Calif., has been legally blind for more than 40 years. An experimental treatment derived from embryonic stem cells seems to have enabled her now to see not just color but also some shapes. Tim Hussin for NPR hide caption

itoggle caption Tim Hussin for NPR