March 5, 2008, 8:19 PM CT

Rats' Twitchy Whiskers In Action

Rats use their whiskers in a way that is closely correlation to the human sense of touch: Just as humans move their fingertips across a surface to perceive shapes and textures, rats twitch their whiskers to achieve the same goal. Now, in a finding that could help further understanding of perception across species, MIT neuroresearchers have used high-speed video to reveal rat whiskers in action and show the tiny movements that underlie the rat's perception of its tactile environment.

Rats rely on whiskers to find their way in the dark, and they devote large areas of their brains to decoding the incoming signals, explains Christopher Moore, a member of the McGovern Institute for Brain Research at MIT and senior author of a study in the February 28th issue of Neuron. Neuroresearchers interested in perception have studied the whisker system intensively, but the information conveyed to the brain by whisker motions has remained a mystery--until now.

"Now that we can see what the rat's whiskers are telling the brain, we can start to understand better how this amazing perceptual system works," says Moore, who is also an assistant professor in MIT's Department of Brain and Cognitive Sciences. "This understanding is relevant not only to the human sense of touch, but to all forms of perception, because every sensory organ is an interface between the mind and the external world"......... Posted by: Kelly      Read more         Source

March 4, 2008, 5:24 PM CT

National Zoo scimitar-horned oryx going into the wild

A male scimitar-horned oryx from the Smithsonians National Zoos Conservation and Research Center in Front Royal, Va., is playing an important role in ensuring the species does not vanish from the planet.

The oryx, along with eight others from American and European zoos, was sent to Tunisia in December 2007 for an eventual reintroduction into the wild, where they have been extinct since the late 1970s. Oryx are a type of desert antelope that are mostly white with reddish-brown necks and marks on the face and a long, dark, tufted tail. They stand up to 4 feet and 6 inches tall at the shoulder, and both male and female oryx have curved horns that grow to be several feet long.

Eventhough the animals have been returned to Tunisia, researchers cannot just simply release them into the wild. For now, the oryx are being kept in a 20,000-acre fenced area in the Dghoumes National Park. Within this protected zone, the five males and four females will reproduce and become acclimated to their arid surroundings. Once a sustainable population has been established, possibly a decade or so from now, the fences will come down.

Oryx were once common in the wild. As recently as 1900, there were as a number of as 1 million of them in North Africa. But their numbers began to dwindle as they were hunted, both for sport and food. To ensure that the same problems do not plague the oryx that are being reintroduced into the wild, the Tunisian government is planning conservation programs to educate local people about the importance of protecting the animals......... Posted by: Kelly      Read more         Source

March 3, 2008, 9:56 PM CT

Sleep patterns of Pigeons

In humans, as in all mammals, sleep consists of two phases: deep, dreamless slow-wave-sleep (SWS) alternates with dream phases, called Rapid Eye Movement (REM)-sleep. Although several studies suggest that information is processed and memories are consolidated during sleep, this remains a hotly debated topic in neurobiology. Comparative studies in birds may help to clarify the function of sleep by revealing overriding principles that would otherwise remain obscure if we only studied mammals. This is because birds are the only taxonomic group other than mammals to show both SWS and REM sleep. Interestingly, the independent evolution of similar sleep states in birds and mammals might be related to the fact that each group also independently evolved large brains capable of performing complex cognitive processes. In their actual study, researchers from the Max-Planck Institute of Ornithology in Seewiesen, Germany showed for the first time that birds compensate for sleep loss in a manner similar to humans (Journal of Sleep Research, Online-Publication February 27, 2008).

During SWS, the synchronous, slow oscillations of neurons are reflected in the EEG (Electroencephalogram), as large slow-waves with a frequency of less than 4 Hz, hence the name slow-wave sleep. The amount of slow-waves is positively correlated with the depth of sleep, and may reflect restorative processes occurring during sleep. Indeed, humans, and other mammals, recover from periods of sleep loss, primarily by increasing the amount of slow-waves, particularly during the first hours of SWS, in essence sleeping more intensely. Although birds also show SWS, it has been unclear whether they show a similar response to sleep loss. Dolores Martinez-Gonzalez and colleagues at the Max Planck Institute for Ornithology in Seewiesen found now, that birds - in this case pigeons - also do not simply shrug of sleep loss......... Posted by: Kelly      Read more         Source

March 3, 2008, 9:49 PM CT

Are wolves the pronghorn's best friend?

As western states debate removing the gray wolf from protection under the Endangered Species Act, a new study by the Wildlife Conservation Society cautions that doing so may result in an unintended decline in another species: the pronghorn, a uniquely North American animal that resembles an African antelope.

The study, appearing in the latest issue of the journal Ecology, says that fewer wolves mean more coyotes, which can prey heavily on pronghorn fawns if the delicate balance between predators and their prey is altered. As per the study, healthy wolf packs keep coyote numbers in check, while rarely feeding on pronghorn fawns themselves. As a result, fawns have higher survival rates when wolves are present in an ecosystem.

People tend to believe that more wolves always mean fewer prey, said WCS researcher Dr. Kim Berger, lead author of the study. But in this case, wolves are so much bigger than coyotes that it doesnt make sense for them to waste time searching for pronghorn fawns. It would be like trying to feed an entire family on a single Big Mac.

Over a three-year period, scientists radio-collared more than 100 fawns in wolf-free and wolf-abundant areas of Grand Teton National Park and monitored their survival throughout the summer. The results showed that only 10 percent of fawns survived in areas lacking wolves, but where coyote densities were higher. In areas where wolves were abundant, 34 percent of pronghorn fawns survived. Wolves reduce coyote numbers by killing them outright or by causing them to shift to safer areas of the Park not utilized by wolves......... Posted by: Kelly      Read more         Source

March 3, 2008, 9:21 PM CT

Low 2007 salmon returns along West Coast

NOAA researchers are reviewing unusual environmental conditions in the Pacific Ocean as the likely culprit for the dramatically low returns of Chinook and coho salmon to rivers and streams along the West Coast of the United States in 2007.

Scientists from NOAAs Northwest and Southwest Fisheries Science Centers are comparing data on the low food production of the California Current in 2005 that occurred when this years returning salmon would have been entering the ocean from their natal streams to feed and grow.

The cold waters of the California Current flow southward from the northern Pacific along the West Coast and are linked to upwelling, an ocean condition caused by winds that bring nutrients to the oceans surface and is the main source of nourishment for the oceans food web. In 2005 a southward shift in the jet stream, delayed favorable winds and upwelling for the California Current, which normally begins in spring. The winds instead arrived in mid-July, causing high surface water temperatures and very low nutrient production within the nearshore marine ecosystem.

We are not dismissing other potential causes for this years low salmon returns, said Usha Varanasi, NOAA Fisheries Service Science Center Director for the Northwest Region. But the widespread pattern of low returns along the West Coast for two species of salmon indicates an environmental anomaly occurred in the California Current in 2005......... Posted by: Kelly      Read more         Source

March 2, 2008, 9:01 PM CT

Darwin was wrong about the origins of chickens

A novel genetic study has revealed why chickens have yellow legs, demonstrating that though Charles Darwin was right about a number of things, his view on the origins of the chicken was not entirely correct. The study, published February 29 in the open-access journal PLoS Genetics, reveals the genetic basis for the appearance of yellow skin in billions of chickens raised worldwide.

Yellow-skinned chickens have a different version of a gene than their white-skinned cousins. Darwin believed that all chickens came from a wild species known as the red junglefowl. When the scientists looked for the yellow-skin gene in the red junglefowl, they only found the genetic variant that codes for white skin. More surprisingly, when they finally did find the yellow-skin version of the gene, it was present in a completely different wild species: the grey junglefowl.

Greger Larson, a Research Fellow at Uppsala University and at Durham University, UK said: Darwin recognized the importance of studying domestic animals as a model of evolution and this insight has proved enormously influential. The ironic thing is that he believed that dogs were hybrids of several wild ancestors but that chickens only had one, and he was wrong on both counts.

Yellow coloring comes from pigments found in feed called carotenoids. The gene in question codes for an enzyme that degrades carotenoids into a colorless form. White-skinned chickens express this enzyme in skin. In contrast, yellowskinned chickens do not express the enzyme in skin, allowing the carotenoids to accumulate and produce yellow coloring. Interestingly, the gene functions normally in other tissues and yellow-skinned chickens have no general defect in carotenoid metabolism......... Posted by: Kelly      Read more         Source

March 2, 2008, 8:58 PM CT

Zebrafish provide useful screening tool for genes

A small striped fish is helping researchers understand what makes people susceptible to a common form of hearing loss, although, in this case, its not the fishs ears that are of interest. As per a research findings reported in the Feb. 29 issue of the journal PLoS Genetics, scientists at the University of Washington have developed a research method that relies on a zebrafishs lateral linethe faint line running down each side of a fish that enables it to sense its surroundingsto quickly screen for genes and chemical compounds that protect against hearing loss from some medications. The study was funded in part by the National Institute on Deafness and Other Communication Disorders (NIDCD), one of the National Institutes of Health.

The fishs lateral line contains sensory cells that are functionally similar to those found in the inner ear, except these are on the surface of the fishs body, making them more easily accessible, said James F. Battey, Jr., M.D., Ph.D., director of the NIDCD. This means that researchers can very efficiently analyze the sensory structures under different conditions to find out what is likely to cause damage to these structures and, on the other hand, what can protect them from damage.

When people are exposed to some antibiotics and chemotherapy agents, the sensory structures in the inner ear, called hair cells, can be irreversibly damaged, resulting in hearing loss and balance problems. Such medications are called ototoxic. People vary widely in their susceptibility to these agents as well as to damage caused by other chemical agents, loud sounds and aging......... Posted by: Kelly      Read more         Source

March 2, 2008, 8:25 PM CT

Ski tourism stressing capercaillie

Ski tourism is raising stress levels among capercaillie, which could harm the birds fitness and ability to breed successfully, ecologists have found. Writing in the British Ecological Societys Journal of Applied Ecology, scientists warn that forests should be kept free from tourism infrastructure if they are inhabited by capercaillie - a species whose numbers are declining markedly across central Europe.

The study by ecologists from Switzerland, Gera number of and Austria used a new technique to assess the impact of ski tourism on capercaillie. Working in the Southern Black Forest in Gera number of, they collected the birds droppings before and after the start of the ski season, and analysed them for levels of the breakdown products of the stress hormone corticosterone. They observed that levels of the breakdown products of the stress hormone were significantly higher in birds living in areas with moderate or high levels of ski tourism.

One of the study's authors, Dr Lukas Jenni of the Swiss Ornithological Institute says: Ski tourism affects both habitat use and stress hormone levels in capercaillie, and this could adversely affect their body condition and overall fitness. Because of this, we recommend that managers keep forests inhabited by capercaillie free from tourism infrastructure and retain undisturbed forest patches within skiing areas......... Posted by: Kelly      Read more         Source

February 26, 2008, 5:38 PM CT

New Paradigm on Ecosystem Ecology

Predators have considerably more influence than plants over how an ecosystem functions, as per a Yale study published recently in Science.

Note: The Canadian Broadcasting Corporation (CBC) interviewed Oswald Schmitz for a story on this research. The interview is available on their site.

The findings, as per the author, Oswald Schmitz, Oastler Professor of Population and Community Ecology at the Yale School of Forestry & Environmental Studies, are a "revolutionary" shift in thinking on the subject. Ecosystem ecologists have long held that plants and their interaction with the soil determine the type and abundance of herbivores and carnivores in an ecosystem. Schmitz's paper, "Effects of Predator Hunting Mode on Grassland Ecosystem Function," shows that the opposite is true.

"Most ecosystem ecologists believe that the supply of nutrients in plants determines who can live up in higher trophic (feeding) levels," said Schmitz. "This study shows that it's the top trophic levels determining how the plants interact with the soil".

In a three-year-long experiment conducted in 14 enclosed cages at Yale-Myers Forest in northeastern Connecticut, Schmitz found that the jumping spider, known also by its Latin name Phidippus rimator, prowls its neighborhood, or ecosystem, and engages in random acts of violence against its plant-eating prey, the garden variety grasshopper (Melanopuls femurrubrum)......... Posted by: Kelly      Read more         Source

February 26, 2008, 5:33 PM CT

'Canaries in the Coal Mine' of Climate Change

As oceans warm and become more acidic, ocean creatures are undergoing severe stress and entire food webs are at risk.

The information was presented by researchers at a press briefing on February 17 at the annual meeting of the American Association for the Advancement of Science in Boston.

Gretchen Hofmann, associate professor of biology at the University of California, Santa Barbara, has just returned from a research mission to Antarctica where she collected pteropods, tiny marine snails the size of a lentil, that she refers to as the "potato chip" of the oceans because they are eaten widely by so a number of species. The National Science Foundation's Office of Polar Programs funded the expedition.

Pteropods are eaten by fish that are in turn consumed by other animals, such as penguins. As these small creatures are stressed by an increasingly acidic ocean, due to the build-up of carbon dioxide in the atmosphere, they are less able to cope with a warmer ocean.

"These animals are not charismatic but they are talking to us just as much as penguins or polar bears," said Hofmann. "They are harbingers of change. It's possible by 2050 they may not be able to make a shell anymore. If we lose these organisms, the impact on the food chain will be catastrophic"......... Posted by: Kelly      Read more         Source