Nell GreenfieldboyceNell Greenfieldboyce is a NPR science correspondent.
Researchers at the U.S. Geological Survey National Wildlife Health Center in Madison, Wis., use eggs to see if the Asian strain of the H5N1 bird flu virus has entered the U.S. in this photo from 2006.
A health official culls chickens on a poultry farm in a village on the outskirts of Katmandu, Nepal. Chickens suspected of being infected with H5N1 bird flu were found in the area in October.
Prakash Mathema/AFP/Getty Images
A prefectural officer carries a chicken on a poultry farm on Oct. 15 on the outskirts of Kathmandu, Nepal, where chickens suspected of being infected with bird flu were found.
Prakash Mathema /AFP/Getty Images
Can You Tell Emotion From Faces Alone? A new study suggests that when people evaluated just facial expressions — without cues from the rest of the body — they couldn't tell if the face was showing a positive or negative emotion. Enlarge this photo to see the answers.
Hillel Aviezer/The Hebrew University of Jerusalem
William Beal, standing at center, started a long-term study on seed germination in 1879. He buried 20 bottles with seeds in them for later researchers to unearth and plant.
Michigan State University
When a case of the potentially lethal H5N1 bird flu was found in British poultry in 2007, Dutch farmers were told to keep their poultry away from wild birds by closing off outdoor areas with wire mesh.
Ed Oudenaarden/AFP/Getty Images