science newsletter: Science News SciGuru.com

Παρασκευή 1 Φεβρουαρίου 2013

Science News SciGuru.com

Owl Mystery Unraveled: Scientists Explain How Bird Can Rotate Its Head Without Cutting Off Blood Supply to Brain
An ideal material: Solving a mystery leads to the discovery of a true topological insulator
New geology study raises questions about long-held theories of human evolution
Scientists Uncover a Previously Unknown Mechanism of Memory Formation
Formula for a biologically effective perfume

Owl Mystery Unraveled: Scientists Explain How Bird Can Rotate Its Head Without Cutting Off Blood Supply to Brain

Posted: 31 Jan 2013 12:46 PM PST

Medical illustrators and neurological imaging experts at Johns Hopkins have figured out how night-hunting owls can almost fully rotate their heads - by as much as 270 degrees in either direction - without damaging the delicate blood vessels in their necks and heads, and without cutting off blood supply to their brains.

An ideal material: Solving a mystery leads to the discovery of a true topological insulator

Posted: 31 Jan 2013 09:22 AM PST

An old material gets a new name, and with it, topological insulators have another chance to shine. Samarium hexaboride (SmB6) has been around since the late 1960s--but understanding its low temperature behavior has remained a mystery until recently. Experimentalists have recently confirmed that this material is the first true 3D topological insulator—as originally predicted by JQI/CMTC theorists in 2010. Topological insulators have been discussed widely as a new area of material science, with the potential to study quantum Hall physics and exotic states such as Majorana fermions.

New geology study raises questions about long-held theories of human evolution

Posted: 31 Jan 2013 09:12 AM PST

While earlier studies on vegetation change through this period relied on the analysis of individual sites throughout the Rift Valley — offering narrow snapshots — Feakins took a look at the whole picture by using a sediment core taken in the Gulf of Aden, where winds funnel and deposit sediment from the entire region. She then cross-referenced her findings with Levin, who compiled data from ancient soil samples collected throughout eastern Africa.

Scientists Uncover a Previously Unknown Mechanism of Memory Formation

Posted: 31 Jan 2013 08:39 AM PST

It takes a lot to make a memory. New proteins have to be synthesized, neuron structures altered. While some of these memory-building mechanisms are known, many are not. Some recent studies have indicated that a unique group of molecules called microRNAs, known to control production of proteins in cells, may play a far more important role in memory formation than previously thought.

Formula for a biologically effective perfume

Posted: 31 Jan 2013 08:27 AM PST

Individual body odour plays an important role in partner selection. Humans, mice, fish and birds, and probably other vertebrates too, receive important information about a potential partner’s immune system from their body odour. A partner is chosen on the bases of whether he or she offers the optimum complement to the individual’s own immune genes. The aim is to pass on a wide variety of immune genes to the offspring so that they are resistant to a broad spectrum of pathogens.