November 5, 2010, 7:55 AM CT
Polar bears can't eat geese into extinction
These are three polar bears near Hudson Bay.
Credit: R. F. Rockwell
As the Arctic warms, a new cache of resourcessnow goose eggsmay help sustain the polar bear population for the foreseeable future. In a newly released study published in an early online edition of
Oikos, scientists affiliated with the Museum show that even large numbers of hungry bears repeatedly raiding nests over a number of years would have a difficult time eliminating all of the geese because of a mismatch in the timing of bear arrival on shore and goose egg incubation.
"There have been statements in popular literature indicating that polar bears can extirpate snow geese quickly once they start to eat eggs," says Robert Rockwell, a research associate in the Division of Vertebrate Zoology at the Museum and a professor at the City University of New York. "However, there will always be the occasional mismatch in the overlap between the onshore arrival of bears and the incubation period of the geese. Even if the bears eat every egg during each year of complete 'match,' our model shows that periodic years of mismatch will provide windows of successful goose reproduction that will partially offset predation effects."
In the last few years, work along the Cape Churchill Peninsula of western Hudson Bay by Rockwell and his colleagues has suggested that polar bears are not as hamstrung by their environment as a number of biologists believe. One new nutritional option for polar bears is the bounty of goose eggs which had previously hatched into goslings that were gone by the time bears came ashore. In recent years, 'early' bears have left breaking sea ice to come ashore and consume eggs. In fact, the earlier the bears come ashore, the better: eggs are higher in nutrients when the embryo is younger.........
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November 3, 2010, 7:59 AM CT
A new protein critical for mitochondria
On the right side we can see aberrant fly and mitochondria when SLIMP is silenced.
A study by the team headed by Lluís Ribas de Pouplana, ICREA professor at the Institute for Research in Biomedicine (IRB Barcelona), has been chosen as "Paper of the week" in the recent issue of the Journal of Biological Chemistry, which is already available online. The article describes the discovery of a new protein in the fly Drosophila melanogaster (fruit fly) that is crucial for mitochondria. The removal of SLIMP in these flies leads to aberrant mitochondria and loss of metabolic capacity, thus causing death.
The study, whose first author is Tanit Guitart, a PhD student in Ribas' lab, has been recognised as "Paper of the week" award because of the "significance and global relevance" of the research performed. Furthermore, the editors have included it among the best studies that have appeared in the journal this year. Of the 6600 articles published, only between 50 and 100 receive the distinction of "Article of the week".
Result of animal evolution.
The SLIMP protein derives from a seryl-tRNA synthetase, universal enzymes that are crucial for the synthesis of new proteins. However, SLIMP has lost its original function and performs a different biological role, which remains to be determined. The scientists studied its possible implication in the regulation of mitochondrial division and the interaction with nucleic acids (DNA, RNA).........
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November 3, 2010, 7:32 AM CT
Getting Rid of Cattle Fever Ticks
ARS researchers have developed new cattle fever tick control measures including this one that automatically applies a pesticide-impregnated neckband to deer feeding at a bait station. Click the image for more information about it.
Researchers at the U.S. Department of Agriculture (USDA) have developed two strategies to ward off cattle fever ticks that are crossing the border from Mexico into the United States. These ticks transmit bovine babesiosis, usually known as Texas cattle fever, a deadly disease of cattle that's caused by singled-celled organisms.
Agricultural Research Service (ARS) researchers in Kerrville, Texas, are in the process of developing and testing new interventions to eliminate cattle fever ticks within U.S. borders and mitigate the impact on the livestock industry. ARS is USDA's principal intramural scientific research agency, and this research promotes the USDA priority of promoting international food security.
The increased spread of infestation is likely due, at least in part, to the increasing populations of white-tailed deer and other wild hoofed animals along the Texas-Mexico border. To control disease-carrying ticks on deer, ARS entomologist J. Mathews Pound and colleagues at the agency's Knipling-Bushland U.S. Livestock Insects Research Laboratory developed a device called the 4-Poster Deer Treatment Bait Station.
The bait station lures deer into a feeding apparatus that uses rollers to apply insecticide to the animal's head, ears and neck. As the deer grooms itself, it transfers the insecticide to other parts of its body, killing most of the ticks on the animal.........
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November 3, 2010, 7:30 AM CT
Vet med's big shift to more women
Veterinarian Carole Bolin prepares to inject a cow with the new vaccine for bovine leptospirosis.
Credit: Photo courtesy of Keith Weller. AVMA.
Women now dominate the field of veterinary medicine the result of a nearly 40-year trend that is likely to repeat itself in the fields of medicine and law.
That's the conclusion of a newly released study that found three factors that appear to be driving the change: the 1972 federal amendment that outlaws discrimination against female students; male applicants to graduate schools who appears to be deterred by a growing number of women enrolling; and the increasing number of women earning Bachelor's degrees in numbers that far exceed those of male graduates, says sociologist Anne E. Lincoln.
An assistant professor in the department of sociology at Southern Methodist University in Dallas, Lincoln is an expert on how occupations transition from being either male- or female-dominated.
Her study is the first of its kind to analyze the feminization of veterinary medicine from the perspective of examining the pool of applicant data to U.S. veterinary medical colleges from 1975 to 1995.
As of 2010, the veterinary profession is about 50 percent men and 50 percent women, as per the American Veterinary Medical Association, while enrollment in veterinary medical colleges is about 80 percent women.
Departure from convention; new methodology.........
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November 1, 2010, 7:57 AM CT
Shape Of Genome Important As Its Content?
three-dimensional structure of the fission yeast genome, S. pombe
If there is one thing that recent advances in genomics have revealed, it is that our genes are interrelated, "chattering" to each other across separate chromosomes and vast stretches of DNA. As per scientists at The Wistar Institute, a number of of these complex associations appears to be explained in part by the three-dimensional structure of the entire genome. A given cell's DNA spends most of its active lifetime in a tangled clump of chromosomes, which positions groups of related genes near to each other and exposes them to the cell's gene-controlling machinery. This structure, the scientists say, is not merely the shape of the genome, but also a key to how it works.
Their study, published online as a featured article in the journal Nucleic Acids Research, is the first to combine microscopy with advanced genomic sequencing techniques, enabling scientists to literally see gene interactions. It is also the first to determine the three-dimensional structure of the fission yeast genome, S. pombe. Applying this technique to the human genome may provide both researchers and physicians a whole new framework from which to better understand genes and disease, the scientists say.
"People are familiar with the X-shapes our chromosomes form during cell division, but what they may not realize is that DNA only spends a relatively small amount of time in that conformation," said Ken-ichi Noma, Ph.D., an assistant professor in Wistar's Gene Expression and Regulation program and senior author of the study. "Chromosomes spend the majority of their time clumped together in these large, non-random structures, and I believe these shapes reflect various nuclear processes such as transcription." .........
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October 22, 2010, 7:50 AM CT
Plants Cleaning up Air Pollution
Poplars, aspens, other trees provide extensive "ecosystem services."
Credit: USDA
Vegetation plays an unexpectedly large role in cleansing the atmosphere, a newly released study finds.
The research, led by researchers at the National Center for Atmospheric Research (NCAR) in Boulder, Colo., uses observations, gene expression studies, and computer modeling to show that deciduous plants absorb about a third more of a common class of air-polluting chemicals than previously thought.
The newly released study, results of which are being published this week in Science Express, was conducted with co-authors from the University of Northern Colorado and the University of Arizona. It was supported in part by the National Science Foundation (NSF), NCAR's sponsor.
"Plants clean our air to a greater extent than we had realized," says NCAR scientist Thomas Karl, the main author. "They actively consume certain types of air pollution".
The research team focused on a class of chemicals known as oxygenated volatile organic compounds (oVOCs), which can have long-term impacts on the environment and human health.
"The team has made significant progress in understanding the complex interactions between plants and the atmosphere," says Anne-Marie Schmoltner of NSF's Division of Atmospheric and Geospace Sciences, which funded the research.........
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October 22, 2010, 7:47 AM CT
High elk-use areas in western Oregon
A cow elk is shown participating in a grazing trial in the Northwest.
Credit: Rachel Cook
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.........
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October 22, 2010, 7:34 AM CT
Chupacabras monster is as much victim as villain
Scientists believe legendary chupacabras monsters are actually coyotes with severe cases of mange, like the animal pictured here.
Credit: Dan Pence
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.........
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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 stressTo 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.........
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October 20, 2010, 7:30 AM CT
Old bees' memory fades
Old bees have troubling finding their way to new homes, as learning behavior becomes inflexible with age.
Credit: Photo credit: Christofer Bang/ASU.
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.........
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