Work by Dr. Gershon and others has shown that serotonin is necessary for the repair of cells in the liver and lungs, and plays a role in normal heart development and bone-mass accumulation.

WSJ: A Gut Check for Many Ailments

The third mistake was that, because the workers were allowed to bypass the time-consuming mixing process in the tower, with its automatic controls for preventing such things happening, they were free to dump their material into a vessel that was not designed to prevent the accumulation of a critical mass sufficient to support a chain reaction.

ECONOMIST: All over in a flash

Scientists compare annual accumulation to the volume of ice lost to sea each year to calculate the ice sheet's overall mass balance and its contribution to sea level rise.

ENGADGET: NASA's GROVER eco-rover to examine Greenland's ice sheet (video)