October 22, 2010, 7:47 AM CT

High elk-use areas in western Oregon

The availability of highly nutritious forage is one of four factors associated with the presence of elk populations in western Oregon and Washington, as per a modeling study recently completed by researchers from the U.S. Forest Service's Pacific Northwest (PNW) Research Station. Findings from the two-year study will be used to update land management planning for the ecologically and economically important ungulate in the region.

"Habitat models like the one we developed are critical to managing elk populations, especially since current management practices are based on decades-old research and are in the process of being updated to reflect new science," said Mary Rowland, a wildlife biologist at the station's La Grande Forestry and Range Sciences Laboratory and one of the study's principal investigators. "Findings from our modeling go a long way in explaining where in western Oregon and Washington elk populations are most likely to thrive."

Rowland and his colleagues used a nutrition model based on elk grazing trials that predicts dietary digestible energy (DDE), a variable that represents nutrition levels based on plant community types. The model was developed by John and Rachel Cook, biologists with the National Council for Air and Stream Improvement, and measures DDE during the summera crucial time for elk that ultimately impacts their survival and reproduction rates. The model can also be used to generate maps depicting areas of the landscape that offer the greatest nutritional resources and the effects of forest management on nutrition levels......... Posted by: Kelly      Read more         Source

October 22, 2010, 7:34 AM CT

Chupacabras monster is as much victim as villain

As Halloween approaches, tales of monsters and creepy crawlies abound. Among the most fearsome is the legendary beast known as the chupacabras.

But the real fiend is not the hairless, fanged animal purported to attack and drink the blood of livestock; it's a tiny, eight-legged creature that turns a healthy, wild animal into a chupacabras, says University of Michigan biologist Barry OConnor.

The existence of the chupacabras, also known as the goatsucker, was first surmised from livestock attacks in Puerto Rico, where dead sheep were discovered with puncture wounds, completely drained of blood. Similar reports began accumulating from other locations in Latin America and the U.S. Then came sightings of evil-looking animals, variously described as dog-like, rodent-like or reptile-like, with long snouts, large fangs, leathery or scaly greenish-gray skin and a nasty odor. Locals put two and two together and assumed the ugly varmints were responsible for the killings.

Researchers studied some of the chupacabras carcasses and concluded that the dreaded monsters actually were coyotes with extreme cases of mange-a skin condition caused by mites burrowing under the skin. OConnor, who studies the mites that cause mange, concurs and has an idea why the tiny assailants affect wild coyotes so severely, turning them into atrocities......... Posted by: Kelly      Read more         Source

October 20, 2010, 7:48 AM CT

Children's best friend

Dogs may not only be man's best friend, they may also have a special role in the lives of children with special needs. As per a new Universit de Montreal study, specifically trained service dogs can help reduce the anxiety and enhance the socialization skills of children with Autism Syndrome Disorders (ASDs). The findings published this year in Psychoneuroendocrinology appears to be a relatively simple solution to help affected children and their families cope with these challenging disorders.

"Our findings showed that the dogs had a clear impact on the children's stress hormone levels," says Sonia Lupien, senior researcher and a professor at the Universit de Montral Department of Psychiatry and Director of the Centre for Studies on Human Stress at Louis-H. Lafontaine Hospital, I have not seen such a dramatic effect before."

Cortisol the telltale indicator of stress

To detect stress-levels, Lupien and his colleagues measured the amount of cortisol present in the saliva of autistic children. Cortisol is a hormone that is produced by the body in response to stress. It peaks half-hour after waking up, known as the cortisol awakening response (CAR) and decreases throughout the day. Moreover, it is detectable in the saliva, which makes sampling its levels easy......... Posted by: Kelly      Read more         Source

October 20, 2010, 7:30 AM CT

Old bees' memory fades

A study published Oct. 19 in the open access journal Public Library of Science (PLoS) ONE, shows that not just human memories fade. Researchers from Arizona State University and the Norwegian University of Life Sciences examined how aging impacts the ability of honey bees to find their way home.

While bees are typically impressive navigators, able to wend their way home through complex landscapes after visits to flowers far removed from their nests, the study reveals that aging impairs the bees' ability to extinguish the memory of an unsuitable nest site even after the colony has settled in a new home.

Typically "from prior studies, we knew that old bees are characterized by poor learning when trained to floral odors in the laboratory," says Gro Amdam, an associate professor in the School of Life Sciences in ASU's College of Liberal Arts and Sciences. "So, we wanted to test whether aging also affects learning behavior that is important for a bee's survival in the wild."

A bee is very well-trained as a forager after three to four days of flight time, Amdam says. Whereas mature bees have piloted their way to and from the hive for five to 11 days and old bees have had more than two weeks of flight time.

To test how old bees adapt to a changed home location, scientists trained bees to a new nest box while their former nest was closed off. Groups composed of mature and old bees were given several days in which to learn the new home location and to extinguish the bees' memory of their unusable former nest box......... Posted by: Kelly      Read more         Source

October 20, 2010, 7:03 AM CT

Sensor derived from frogs

Princeton engineers have developed a sensor that may revolutionize how drugs and medical devices are tested for contamination, and in the process also help ensure the survival of two species of threatened animals.

To be fair, some of the credit goes to an African frog.

In the wild, the African clawed frog produces antibacterial peptides -- small chains of amino acids -- on its skin to protect it from infection. Princeton scientists have found a way to attach these peptides, which can be synthesized in the laboratory, to a small electronic chip that emits an electrical signal when exposed to harmful bacteria, including pathogenic E. coli and salmonella.

"It's a robust, simple platform," said Michael McAlpine, an assistant professor of mechanical and aerospace engineering and the lead researcher on the project. "We think these chips could replace the current method of testing medical devices and drugs".

A paper outlining their development of the sensor was published online October 18 in the Proceedings of the National Academy of Science The research was funded by the American Asthma Foundation and by the Air Force Office of Scientific Research.

The current testing method has a major drawback: It relies on the blood of the horseshoe crab, a species that is roughly 450 million years old. The horseshoe crab population has declined in recent years, and as a result, so too has the population of a bird that feasts on the crab......... Posted by: Kelly      Read more         Source

October 15, 2010, 6:38 AM CT

Humidity makes gecko feet stickier

Human adhesives are famed for their fallibility. Gooey glues soon lose their grip, are easily contaminated and leave residues behind. But not gecko feet. Geckos can cling on repeatedly to the smoothest surfaces thanks to the self-cleaning microscopic spatula-shaped hairs (setae) that coat the soles of their feet. Back in 2002, Kellar Autumn observed that these dry hairs are in such intimate contact with surfaces that the reptiles 'glue' themselves on by van der Waals forces with no need for fluid adhesives. More recent studies had suggested that geckos might benefit from additional adhesion in humid environments through capillary action provided by microscopic droplets of water sandwiched between setae and the surface. But Autumn wasn't so sure, so he and his lab at Lewis and Clark College and the University of Washington, USA, began testing gecko grip to find out how increasing humidity helps them hold tight Autumn publishes his team's discovery that humidity helps geckos grip tighter by softening the surface of their feet on 15 October 2010 in The Journal of Experimental Biology at http://jeb.biologists.org.

Knowing that geckos replace lost setae when they moult, Autumn, his postdoc Jonathan Puthoff, and Matt Wilkinson collected patches of the 'sticky' hairs from gecko feet and attached them to a mechanical testing device, known as 'Robotoe', that reproduces the way the reptile drags its foot as it contacts a surface. Dragging the setae across two surfaces (one that repelled water and another that attracted water) at different velocities and in environments ranging from 10% to 80% humidity, the team tested whether microscopic water bridges formed in high humidity were helping the geckos hang on. They reasoned that if the reptiles were using microscopic water bridges then the setae would bond more tightly to the surface that attracted water than the surface that repelled water. But when they measured the setae's adhesion and friction it was essentially the same on the two surfaces. And when the team compared the adhesion of setae that were moving too fast to form water bridges with that of slowly moving feet that could possibly form water bridges, there was no difference. The geckos were not supplementing their van der Waals attachment forces with capillary forces from water bridges. So how were they holding on tighter?........ Posted by: Kelly      Read more         Source

October 11, 2010, 7:57 AM CT

Plants kick-start evolutionary drama

An international team of scientists, exploiting pioneering techniques at Arizona State University, has taken a significant step toward unlocking the secrets of oxygenation of the Earth's oceans and atmosphere.

Evolution of the Earth's multitude of organisms is intimately associated with the rise of oxygen in the oceans and atmosphere. The new research indicates that the appearance of large predatory fish as well as vascular plants approximately 400 million years ago coincided with an increase in oxygen, to levels comparable to those we experience today. If so, then animals from before that time appeared and evolved under markedly lower oxygen conditions than previously thought.

The researchers, including collaborators from Harvard, Denmark, Sweden and the United Kingdom, made use of a method developed at ASU by Ariel Anbar, a professor in the department of chemistry and biochemistry and the School of Earth and Space Exploration in the College of Liberal Arts and Sciences, and his research group. The method can be used to estimate global oxygen levels in ancient oceans from the chemical composition of ancient seafloor sediments.

Their important findings are presented in a paper published in this week's online Early Edition of the Proceedings of the National Academy of Sciences (PNAS), titled "Devonian rise in atmospheric oxygen corcorrelation to radiations of terrestrial plants and large predatory fish"......... Posted by: Kelly      Read more         Source