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November 19, 2008, 8:34 PM CT

Angular observation of joints of geckos moving

Angular observation of joints of geckos moving
Scholars in the Institute of Bio-inspired Structure and Surface Engineering (IBSS), Nanjing University of Aeronautics and Astronautics (NUAA) used a three-dimensional locomotion video-recording and measuring system to observe and measure the angular rotation of joints in gecko's limbs when they were running on horizontal floor and climbing on vertical wall. This work helps us to understand gecko's locomotion from the view point of angle change of joints and to provide a direct reference to plan the gait of gecko-robots.

This research was published in Chinese Science Bulletin, Volume 53, Issue 22, 2008 and waccording toformed by Li Hongkai, Dai Zhendong, Shi Aiju, Zhang Hao, Sun Jiurong.

Geckos have excellent locomotion abilities to move on various surfaces. The ability is highly desired by the robot moving in unstructured environments, particularly legged robots. But the stability, agility, robustness, environmental adaptability, and energy efficiency of modern robots lag far behind that of correspondent animals. This research provides an insight into how geckos coordinate the joint angles on limbs and meet the requirements of moving on various surfaces.

The angular observation waccording toformed to describe the difference between the locomotion on horizontal and vertical surfaces. The data collected from huge video recording and long vapid processing reveal the spatio-temporal rotation trajectory, extrema, ranges of each joint in forelimb and hind limb, the phase diagram of limb angles. Results of the experiments provide a direct intuitionistic presentation about the gait of gecko moving on horizontal and vertical surfaces with different speed.........

Posted by: Kelly      Read more         Source


November 19, 2008, 7:39 PM CT

Worker ants of the world, unite! You have nothing to lose but your fertility

Worker ants of the world, unite!  You have nothing to lose but your fertility
The highly specialized worker castes in ants represent the pinnacle of social organization in the insect world. As in any society, however, ant colonies are filled with internal strife and conflict. So what binds them together? More than 150 years ago, Charles Darwin had an idea and now he's been proven right.

Evolutionary biologists at McGill University have discovered molecular signals that can maintain social harmony in ants by putting constraints on their fertility. Dr. Ehab Abouheif, of McGill's Department of Biology, and post-doctoral researcher, Dr. Abderrahman Khila, have discovered how evolution has tinkered with the genes of colonizing insects like ants to keep them from fighting amongst themselves over who gets to reproduce.

"We've discovered a really elegant developmental mechanism, which we call 'reproductive constraint,' that challenges the classic paradigm that behaviour, such as policing, is the only way to enforce harmony and squash selfish behaviour in ant societies," said Abouheif, McGill's Canada Research Chair in Evolutionary Developmental Biology.

Reproductive constraint comes into play in these ant societies when evolutionary forces begin to work in a group context rather than on individuals, the scientists said. The process can be seen in the differences between advanced ant species and their more primitive cousins. The study was reported in the Nov. 18 edition of the Proceedings of the National Academy of Sciences........

Posted by: Kelly      Read more         Source


November 14, 2008, 9:25 PM CT

DNA provides 'smoking gun' in the case of the missing songbirds

DNA provides 'smoking gun' in the case of the missing songbirds
Tom Eckert
A Townsend's warbler perched in an evergreen tree.

It sounds like a tale straight from "CSI": The bully invades a home and does away with the victim, then is ultimately found out with the help of DNA evidence.

Except in this instance the bully and the victim are two species of songbirds in northwest North America, and the DNA evidence shows conclusively that one species once occupied the range now dominated by the other.

The case started about 400,000 years ago when encroaching glaciers split a single warbler species into two separate groups that eventually became distinct species, with hermit warblers living in coastal areas from northern California to Alaska and Townsend's warblers living farther inland in Oregon, Washington, Idaho and Montana.

When the glaciers melted, the Townsend's warblers gradually expanded their range northward into British Columbia and Alaska before spilling over to the Pacific Coast into territory occupied by hermit warblers.

That's when things got tough for the hermit warblers, said Meade Krosby, a University of Washington doctoral student in biology who has found genetic evidence of the struggle between the two species. She cited prior studies showing Townsend's males with higher testosterone levels and superior fighting ability than hermit males.

"The Townsend's were brutes and they just smacked the hermit warblers out of the way," Krosby said.........

Posted by: Kelly      Read more         Source


November 14, 2008, 9:22 PM CT

Virunga Conflict Escalates, Gorillas at Risk

Virunga Conflict Escalates, Gorillas at Risk
Located in the Democratic Republic of Congo on the border with Rwanda and Uganda, Virunga National Park is home to more than half the world's 700 remaining mountain gorillas and the world's only golden monkey population.
© Martin Harvey / WWF-Canon
The ongoing conflict in the eastern Democratic Republic of Congo has recently intensified. As a result more than 50 Congolese park rangers fled to safety from Virunga National Park and more than one million people have been displaced. The rebels have advanced to just outside of Goma - the regional capital - threatening the stability of the entire country.

While prior fighting had taken place inside some sectors of Virunga National Park, and rebel control of the park included all of the habitats where mountain gorillas are found - this is the first time that the park's headquarters have been taken over and occupied by the troops. More than half of the world's 700 remaining mountain gorillas live inside the park, along with hundreds of bird and mammal species. Because rangers are unable to conduct patrols, the status of the park's gorillas is unknown.

"Armed conflicts are disastrous on a number of levels, including their impact on the environment. WWF urges all involved to remember that a healthy Virunga National Park is vital to its wildlife and the local community - particularly after the conflict when tourism can help speed the region's recovery," says Dr. Richard Carroll, managing director of WWF's Congo Basin program.

The unfolding humanitarian crisis is another threat to Virunga National Park. The displaced people urgently need basic supplies to survive - particularly firewood to cook meals and heat their temporary homes. WWF is partnering with the United Nations and other organizations to provide firewood from sustainable sources to alleviate pressure on Virunga National Park's forests. The park has yet to recover from the period during 1994-95, when hundreds of thousands of refugees fleeing Rwanda arrived in the region, with no alternatives but to destroy large sections of the park's forests. Also, without regular patrols by the park's rangers, bushmeat hunting and the illegal charcoal trade could thrive in the chaos.........

Posted by: Kelly      Read more         Source


November 14, 2008, 9:18 PM CT

Danger: Elephant Crossing

Danger: Elephant Crossing
Why didn't the forest elephant cross the road? It feared for its life, as per results of a new study by the Wildlife Conservation Society (WCS) and Save the Elephants.

The threat of encounters with poachers rises as new roadways are carved into wildlife habitat in Central Africa's Congo Basin. Because these highly intelligent animals now associate roads with danger, they are avoiding them at all costs.

The authors of the study tracked 28 forest elephants with GPS collars and observed that they have adopted a "siege mentality." Only one of the elephants crossed a road outside of a protected area. As it crossed, it traveled at 14 times its normal pace.

Forest elephants showed adverse reactions to roads even in the largest remaining wilderness areas in Central Africa. This is bad news for these endangered pachyderms, since a boom in road building is underway.

"Forest elephants are basically living in fear.....in prisons created by roads. They are roaming around the woods like frightened mice rather than tranquil, formidable giants of their forest realm," said Dr. Stephen Blake, the study's lead author. He added that starvation, disease, stress, infighting, and social disruption are likely to result.

Losing access to food and important mineral deposits may elicit aggressive and other negative behaviors among different social groups, which in turn can affect reproductive success. Other negative impacts include overgrazing of local vegetation and reduced seed dispersal by elephants, which is vital to helping regenerate forests.........

Posted by: Kelly      Read more         Source


November 14, 2008, 9:05 PM CT

Rare Cat Captured

Rare Cat Captured
Clay Miller (right) of WCS and John Lewis (left) of Wildlife Vets International listen to Alyona's heartbeat.
©Andrew Harrington
The world's rarest big cat recently emerged in the Russian Far East, proving this critically endangered leopard is still hanging tough. Scientists from the Wildlife Conservation Society (WCS) captured and released "Alyona," a female Far Eastern leopard, in Russia at the end of October. She is one of an estimated 25 to 40 of these big cats in existence.

The capture was made in Primorsky Krai along the Russia-China border. Researchers from the Russian Academy of Sciences Institute of Biology and Soils (IBS) were also on the scene. The team is working with Wildlife Vets International, National Cancer Institute, and the Zoological Society of London to evaluate the health and potential effects of inbreeding for this tiny population. Experts believe it contains no more than 10 to 15 females. Three leopards captured previously in 2006 and 2007 all exhibited significant heart murmurs, which may reflect inherited disorders.

Alyona was in good shape and weighed a healthy 85 pounds. A preliminary health analysis pegged her as 8-10 years old. After the physical exam, she was released.

To help increase genetic diversity in the Far Eastern leopard population, researchers are considering translocating leopards from other areas. A similar effort helped revive the Florida panther, when animals were relocated from Texas. Today, Florida panthers have risen from fewer than ten individuals to a population of approximately 100.........

Posted by: Kelly      Read more         Source


November 14, 2008, 8:55 PM CT

Insight into the evolution of parasitism

Insight into the evolution of parasitism
The nematode Pristionchus pacificus (left) and its host, the dung beetle (right).

Image: Jürgen Berger / Dan Bumbarger / Max Planck Institute for Developmental Biology
Researchers at the Max Planck Institute for Developmental Biology, together with American colleagues, have decoded the genome of the Pristionchus pacificus nematode, thereby gaining insight into the evolution of parasitism. In their work, which has been reported in the latest edition of Nature Genetics, the researchers from Professor Ralf J. Sommer's department in Tübingen have shown that the genome of the nematode consists of a surprisingly large number of genes, some of which have unexpected functions. These include many genes that are helpful in breaking down harmful substances and for survival in a strange habitat: the Pristionchus uses beetles as a hideout and means of transport, feeding on the fungi and bacteria that spread out on their carcasses once they have died. It thus provides the clue to understanding the complex interactions between host and parasite. (Nature Genetics, September 22, 2008).

With well over a million different species, nematodes are the largest group in the animal kingdom. The worms, commonly only just one millimetre in length, are found on all continents and in all ecosystems on Earth. Some, as parasites, are major pathogens to humans, animals and plants. Within the group of nematodes, at least seven forms of parasitism have developed independently from one another. One member of the nematode group has acquired a certain degree of fame: due to its humble lifestyle, small size and quick breeding pattern, the Caenorhabditis elegans is one of the most popular animals being used as a model in biologists' laboratories. It was the first multicellular animal whose genome was completely decoded in 1998.........

Posted by: Kelly      Read more         Source


November 14, 2008, 8:36 PM CT

Females compensate for unattractive partners

Females compensate for unattractive partners
The zebra finch forms long-term pair bonds. Female zebra finches pull out all the stops to compensate for the shortcomings of unattractive partners.

Image: Max Planck Institute for Ornithology
Attractive males promise quality offspring. Most female birds therefore invest a lot of energy in their attempts to breed with attractive partners. Not so the female zebra finch. If they have unattractive male partners, the females lay especially big eggs that contain a lot of nutrients. Because the finch pairs stay together for their entire lifespan, the female has no reason to save up resources for a subsequent and better partner. The low genetic quality of the male is compensated for by good egg quality, as discovered by the researchers at the Max Planck Institute for Ornithology in Seewiesen (Proceedings, 5 November 2008).

Female birds commonly breed several times over the course of their lives. At each breeding attempt they face the question as to what level of resources they should invest in the process. The genetic quality of their breeding partners plays an important role here as attractiveness is linked to the promise of healthy offspring. If the male bird is especially attractive, the females summon up a especially high level of energy for their breeding attempts. As a result, the eggs are relatively large or contain a especially high level of nutrients like carotenoids, for example.

However, as the researchers at the Max Planck Institute for Ornithology in Seewiesen have discovered, in the case of zebra finches, the opposite approach can also be advantageous. The explanation for this lies in the way in which zebra finches live together: the couples commonly remain together for their entire lifespan and are, therefore, monogamous. Thus, it does not pay for the females to economize with their resources as there is little likelihood that they will team up with a real "superman" for their next breeding attempt.........

Posted by: Kelly      Read more         Source


November 14, 2008, 8:15 PM CT

Singing in slow motion

Singing in slow motion
Photo courtesy / Michale Fee and Michael Long, MIT
As anyone who watched the Olympics can appreciate, timing matters when it comes to complex sequential actions. It can make a difference between a perfect handspring and a fall, for instance. But what controls that timing? MIT researchers are closing in on the brain regions responsible, thanks to some technical advances and some help from songbirds.

"All our movements, from talking and walking to acrobatics or piano playing, are sequential behaviors," explained Michale Fee, an investigator in the McGovern Institute for Brain Research at MIT and an associate professor in MIT's Department of Brain and Cognitive Sciences. "But we haven't had the necessary tools to understand how timing is generated within the brain."

Now Fee and his colleagues report in the Nov. 13 issue of Nature a new method for altering the speed of brain activity. And using that technique, "we think we have found the clock that controls the timing of the bird's song," Fee said.

The zebra finch's song is widely studied as a model for understanding how the brain produces complex behavior sequences. Each song lasts about one second, and contains multiple syllables in a highly stereotypic sequence. Two brain regions -- the High Vocal Center (HVC) and the robust nucleus of the arcopallium (RA) -- are known to be important for singing, because deactivating either region prevents song production. But uncovering the clock mechanism mandatory a more subtle method.........

Posted by: Kelly      Read more         Source


November 11, 2008, 9:35 PM CT

Stem Cells from Monkey Teeth Can Stimulate Growth

Stem Cells from Monkey Teeth Can Stimulate Growth
Scientists at the Yerkes National Primate Research Center, Emory University, have discovered dental pulp stem cells can stimulate growth and generation of several types of neural cells. Findings from this study, available in the recent issue of the journal Stem Cells, suggest dental pulp stem cells show promise for use in cell treatment and regenerative medicine, especially therapies linked to the central nervous system.

Dental stem cells are adult stem cells, one of the two major divisions of stem cell research. Adult stem cells have the ability to regenerate a number of different types of cells, promising great therapeutic potential, particularly for diseases such as Huntington's and Parkinson's. Already, dental pulp stem cells have been used for regeneration of dental and craniofacial cells.

Yerkes researcher Anthony Chan, DVM, PhD, and his team of scientists placed dental pulp stem cells from the tooth of a rhesus macaque into the hippocampal areas of mice. The dental pulp stem cells stimulated growth of new neural cells, and a number of of these formed neurons. "By showing dental pulp stem cells are capable of stimulating growth of neurons, our study demonstrates the specific therapeutic potential of dental pulp stem cells and the broader potential for adult stem cells," says Chan, who also is assistant professor of human genetics in Emory School of Medicine. Because dental pulp stem cells can be isolated from anyone at any age during a visit to the dentist, Chan is interested in the possibility of dental pulp stem cell banking. "Being able to use your own stem cells for treatment would greatly decrease the risk of cell rejection that we now experience in transplant medicine," says Chan.........

Posted by: Kelly      Read more         Source

   

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