Twelve healthy subjects in their 60s and 70s showed a different pattern of brain activations during thirst and satiation than did 10 healthy subjects in their 20s who drank the same amounts and underwent imaging with positron-emission tomography (PET). Dysfunction in activated neural regions could help explain why older adults show the dangerous tendency toward reduced drinking in response to dehydration.

San Antonio and Australian researchers reported the PET study of thirst in this week’s Proceedings of the National Academy of Sciences Online Early Edition.

The team has conducted a series of studies to catalog brain activations to basic physiologic necessities such as thirst, body temperature regulation, air hunger and pain relief.

Chemical engineering researchers at the University of Arkansas have investigated supercritical methanol as a method of converting chicken fat into biodiesel fuel. The new study also successfully converted tall oil fatty acid, a major by-product of the wood-pulping process, into biodiesel at a yield of greater than 90 percent, significantly advancing efforts to develop commercially viable fuel out of plentiful, accessible and low-cost feedstocks and other agricultural by-products.

“Major oil companies are already examining biodiesel as an alternative to petroleum,” said R.E. “Buddy” Babcock, professor of chemical engineering.

Mathematicians from the University of Exeter say they have solved the mystery of traffic jams by developing a model to show how major delays occur on our roads, with no apparent cause.

Many traffic jams leave drivers baffled as they finally reach the end of a delay only to find no visible cause for their delay. Now, a team of mathematicians state they have found the answer and published their findings in the journal Proceedings of the Royal Society.

The team developed a mathematical model to show the impact of unexpected events. Their model revealed that slowing down below a critical speed when reacting to such an event, a driver would force the car behind to slow down further and the next car back to reduce its speed further still.

A new study of twins indicates that the genetic foundation for the brain’s ability to recognize faces and places is much stronger than for other objects, such as words. The results, which appear in the December 19 issue of the Journal of Neuroscience, are some of the first evidence demonstrating the role of genetics in assigning these functions to specific regions of the brain.

“We are social animals who have specialized circuitry for faces and places,” says Arthur W. Toga, PhD, director of the Laboratory of NeuroImaging at UCLA School of Medicine. “Some people are better at recognizing faces and places, and this study provides evidence that it is partially determined by genetics.”

A research team at Maryland's A. James Clark School of Engineering comprised of Professor Christopher Davis, Research Scientist Igor Smolyaninov, and graduate student Yu-Ju Hung, has used plasmon technology to create the world's first invisibility cloak for visible light. The engineers have applied the same technology to build a revolutionary superlens microscope that allows scientists to see details of previously undetectable nanoscale objects.

Generally speaking, when we see an object, we see the visible light that strikes the object and is reflected. The Clark School team's invisibility cloak refracts (or bends) the light that strikes it, so that the light moves around and past the cloak, reflecting nothing, leaving the cloak and its contents "invisible."

Scientists long have focused on how climate and vegetation allowed human ancestors to evolve in Africa.