A mouse's heart beats about the same number of times in its lifetime as an elephant's, but a mouse only lives for about a year while an elephant will live to be about 70.

Why do small plants and animals mature faster than large ones? Why has nature chosen such radically different forms as the loose-limbed beauty of a flowering tree and the fearful symmetry of a tiger? 

Does cortisol, the stress hormone, cause risk aversion and 'irrational pessimism' in bankers and fund managers during financial crises?

The authors of a paper in
Proceedings of the National Academy of Sciences
correlate the fact that traders exhibit risk averse behavior during periods of extreme market volatility – when a crashing market most needs them to take risks, according to academics not responsible for billions of dollars of someone else's money – and that this change in their appetite for risk may be "physiologically-driven", specifically by the body's response to cortisol. They suggest that stress could be an "under-appreciated" cause of market instability.

Older football veterans contend that modern equipment, and its ability to protect players from injury, ironically lead to more of it. Rugby players agree. 

They may be right. A new study finds that modern football helmets do little to protect against hits to the side of the head and the rotational force that is often a dangerous source of brain injury and encephalopathy. 

Policy makers are in constant discussion about a range of climate change mitigation possibilities and among the least understood are geoengineering methods.

The injection of sulfate particles into the atmosphere to reflect sunlight and curb the effects of global warming could pose a severe threat if not maintained indefinitely and also supported by strict reductions in greenhouse gas (GHG) emissions, write  University of Washington researchers in Environmental Research Letters.

If we want to see worldwide trends in public health, look to the South Pacific archipelago of Samoa and American Samoa.

About 75 percent of the U.S. territory's adult population is obese, the highest rate in the world. Rates of type 2 diabetes top 20 percent and a recent study found that the elevated obesity rates are now even present in newborns.

This obesity epidemic began there a few decades ago. Brown University epidemiologist Stephen McGarvey has investigated the obvious question: How did all this happen?

Tularemia, also called "rabbit fever",  is, unlike anthrax or smallpox, the bioweapon you are least likely to know about.

But it is common in the northeastern United States and because it has been weaponized in various parts of the world could be a significant risk to biosecurity.

At the Annual Biophysical Society Meeting in San Francisco, Geoffrey K. Feld, a Postdoctoral researcher in the Physical&Life Sciences Directorate at Lawrence Livermore National Laboratory (LLNL), described the team's work to uncover the secrets of the bacterium Francisella tularensis, which causes tularemia.