Despite popular perceptions that cheerleading is dangerous, it is relatively safe - but it's not perfect and when injuries do happen they tend to be severe.

A new movie is out this month on NFL concussions, and the doctor who is the subject of the piece says football for anyone under age 18 should be banned - but an upcoming white paper from the American Council on Science and Health notes that a ban may be too heavy-handed. Cheerleading also has a lot of head injuries and concussions are not the top injury in youth football.

Clouds can increase warming in the changing Arctic region more than scientists expected, by delivering an unexpected double-whammy to the climate system, according to a new study by researchers at NOAA, the University of Colorado Boulder and colleagues.

Many strokes that required immediate treatment in emergency rooms may have been preventable, but stroke prevention has not advanced the way therapy for acute stroke has. Stroke prevention has fallen by the wayside as stroke patient outcomes have improved but the close monitoring of blood pressure, cholesterol levels and cardiac conditions remain important, finds a paper in JAMA Neurology.

Using a prevention scale they developed for this study, University of California Irvine neurologist Dr. Mark Fisher and colleagues discovered that 76 percent of acute stroke patients exhibited some degree of stroke preventability, while 26 percent exhibited high preventability.

A pesticide called heptachlor epoxide and used in 1970s was found in milk at that time - and it being linked to Parkinson's disease now, in a paper in Neurology.

Syracuse Earth sciences professor Christopher Scholz and former Ph.D. student Robert Lyons have an unprecedented glimpse into the past of a lake with explosive biodiversity. Along with colleagues from six other universities, Scholz and Lyons have unearthed a 380-meter-deep time capsule from Lake Malawi.

Lyons says the core shows that "East African moisture history over the last 1.3 million years is a lot more complicated than was previously postulated."

It has long been suspected that sulfur emissions can brighten clouds. Water droplets tend to clump around particles of sulfuric acid, causing smaller droplets that form brighter, more reflective clouds.

But while humans have pumped sulfur into Earth's atmosphere since the Industrial Revolution, it's been hard to measure how this affects the clouds above. New University of Washington research uses a huge volcanic eruption in Iceland to measure the change.

The new study, to be published in Geophysical Research Letters, a journal of the American Geophysical Union, shows that sulfur emissions do indeed result in smaller cloud droplet size, leading to brighter clouds that reflect significantly more sunlight.