Geologists have long thought that the rapid global cooling period nearly 13,000 years ago known as the Younger Dryas (Big Freeze) was triggered by the melting Laurentide ice sheet. But geological evidence for that theory has been lacking so far.

Now researchers writing in Nature say they have identified the mega-flood path across North America that channeled melt-water from the giant ice sheet into the oceans,  triggering the Younger Dryas cold snap.

Researchers from Uppsala and Stockholm Universities say that the hunter-gatherers who inhabited the southern coast of Scandinavia 4,000 years ago were lactose intolerant.

The conclusion suggests that today's Scandinavians are not descended from the Stone Age people in question but from a group that arrived later. Results of the research have been published in the journal BMC Evolutionary Biology.

"This group of hunter-gatherers differed significantly from modern Swedes in terms of the DNA sequence that we generally associate with a capacity to digest lactose into adulthood," says Anna Linderholm, formerly of the Archaeological Research Laboratory, Stockholm University.

Silicon is the basic material for most microprocessors and memory chips. But for a long time the electronics industry has been pursuing novel organic materials to create semiconductor products—materials that perhaps could not be packed as densely as state-of-the-art silicon chips, but that would require less power and cost less.

According to scientists at the National Institute of Standards and Technology (NIST), an organic semiconductor may be a viable candidate for creating large-area electronics, such as solar cells and displays that can be sprayed onto a surface as easily as paint.

How quickly the Andes Mountains reached their current height, an average elevation of 13,000 feet, has been a contentious debate in geological circles. Some researchers claim the mountains rose abruptly and others maintain that the uplift was a more gradual process.

Paleoclimatologists writing in Science suggests that the quick-rise view is based on misinterpreted evidence. What some geologists interpret as signs of an abrupt rise are actually indications of ancient climate change, the researchers say. The confusion results when ratios of oxygen's two main isotopes, oxygen-18 and oxygen-16, are used to estimate past elevation.

However cute they may be, fat babies are likely to develop motor skills slower than their thinner counterparts, says a study just published in the Journal of Pediatrics.

The findings are based on observations of 217 African-American first-time mothers who participated in the Infant Care, Feeding and Risk of Obesity Study. The project is examining – in a population at risk of obesity – how parenting and infant feeding styles relate to infant diet and the risk of babies becoming overweight.

Scientists have fine-tuned computer models that can indicate when forest "carbon sinks" actually become net carbon generators instead.

The effort, detailed in Global Change Biology, will help pinpoint the effectiveness of trees in offsetting carbon releases that contribute to higher atmospheric temperatures and global climate change.

Since U.S. forests absorb and store about 750 million metric tons of carbon dioxide each year, managing forest resources to optimize carbon sequestration is essential to mitigating the effects of climate change, the authors say.