Polar bears were added to the threatened species list nearly three years ago when their icy habitat showed steady, precipitous decline because of a warming climate. But it appears the Arctic icons aren't necessarily doomed after all, according to results of a study published in this week's issue of the journal Nature. The findings indicate that there is no "tipping point" that would result in unstoppable loss of summer sea ice when greenhouse gas-driven warming rises above a certain threshold.

A small area deep in the brain called the perirhinal cortex is critical for forming unconscious conceptual memories, researchers at the UC Davis Center for Mind and Brain have found.

Scientists from all over the world are taking a second, more expansive, look at the car-sized asteroid that exploded over Sudan's Nubian Desert in 2008, with major implications for the meteorite's origin. In the first round of research, Carnegie Geophysical scientist Doug Rumble examined one fragment of the asteroid and determined that it fell into a very rare category called ureilites. Now Rumble has expanded his work to examine 11 meteorite fragments, focusing on the presence of oxygen isotopes.

Sea-ice habitats essential to polar bears would likely respond positively should more curbs be placed on global greenhouse gas emissions, according to a new modeling study published today in the journal, Nature. The study, led by the US Geological Survey, included university and other federal agency scientists.

A research team led by scientists at Brown University and the University of California, San Francisco, have associated a mutation found in many kinds of brain tumors with a molecular process that affects metabolism genes. The discovery may open the door to developing new treatments for the deadly cancers.

Body fat distribution does not play an important role in the incidence of every subtype of premenopausal breast cancer, but is associated with an increased risk for estrogen receptor-negative breast cancer, according to a study published Dec. 15 in the Journal of the National Cancer Institute.

America is winning a battle against heart disease and stroke mortality, but is still losing the war, according to the American Heart Association.

Scientists from deCODE genetics and academic colleagues today report the discovery of a set of single-letter variations in the sequence of the human genome (SNPs) that impact individual baseline levels of prostate specific antigen, or PSA. The analysis of four SNPs can be used to derive a personalized PSA threshold that more accurately identifies those men who are more likely to have a positive biopsy and for whom one should therefore be recommended.

Requiring a second exam on a person who is considered brain dead may be unnecessary, according to a study on the impact of a second brain death exam on organ donation rates. The research is published in the Dec. 15, 2010, online issue of Neurology, the medical journal of the American Academy of Neurology.

Not a happy holiday thought, but an important one: The number of babies who die of SIDS, or sudden infant death syndrome, surges by 33 percent on New Year's Day. The suspected reason? Alcohol consumption by caretakers the night before.

Brown University sociologist John Logan is among the first scholars to analyze new US census data on social, economic, housing and demographic factors for every community in the nation. His findings show that as diversity in the nation grows, progress toward integrating neighborhoods appears to have stopped.

Is red seaweed a viable future biofuel? Now that a University of Illinois metabolic engineer has developed a strain of yeast that can make short work of fermenting galactose, the answer is an unequivocal yes. Yong-Su Jin and his colleagues have recently identified three genes in Saccharomyces cerevisiae, the microbe most often used to ferment the sugars, whose overexpression increased galactose fermentation by 250 percent when compared to a control strain.

Research published this week in PLoS One provides insight for the conservation of small cetaceans by demonstrating that Franciscana dolphins accidentally entangled in fishing nets include genetic relatives, or mother-offspring pairs.

Absence makes your heart grow fonder, but close quarters may boost your career.According to new research by scientists at Harvard Medical School, the physical proximity of researchers, especially between the first and last author on published papers, strongly correlates with the impact of their work.

Through analyzing the locations of authors of academic papers, researchers have determined that physical proximity of collaborators, especially between the first and last author, correlates with how widely the paper is cited.