2009年9月23日星期三

NY researchers breeding rare native ladybugs

This June 18, 2009 photo provided by Cornell University shows a nine-spotted ladybug in a lab at Cornell in Ithaca, N.Y. A year after they launched a nationwide search for dwindling native ladybugs, New York researchers are breeding colonies of them from insects found by citizen scientists in Oregon and Colorado. Of particular interest are the nine-spotted, two-spotted and transverse ladybugs, three native species that have declined dramatically in the last decade. (AP Photo)

A year after they launched a nationwide search for dwindling native ladybugs, New York researchers are breeding colonies of them from insects found by citizen scientists in Oregon and Colorado.

John Losey, an entomologist at Cornell University, launched the Lost Ladybug Project last year to try to figure out why once-common native ladybug species had all but disappeared across the country. The project, funded by the National Science Foundation, recruits citizen scientists 鈥?especially children 鈥?to search for ladybugs and send photos of them to Losey and his colleagues.

Of particular interest are the nine-spotted, two-spotted and transverse ladybugs, three native species that have declined dramatically in the last decade, possibly because of the release of non-native species to control crop pests.

"Between 1999 and last year when we started the program, less than 10 individuals of the nine-spot were collected anywhere in the country," Losey said. "That used to be the most dominant species across the U.S. and Canada."

Hundreds of participants across the U.S. and Canada have sent in thousands of photos since the project launched. While some of the photos were of native species, most of the pictures showed the multicolored Asian ladybug and the European seven-spotted ladybug, which were introduced for agricultural pest control and have become widespread as the dominant species.

The big breakthrough came in June, when 6-year-old Alyson Yates and her mom, Kate, started sending in photos of nine-spotted ladybugs from their rural backyard in Lakeview, Ore., in the sagebrush desert east of the Cascades.

"It was really an amazing find," Losey said. "Usually, someone just finds one or two. Alyson and Kate sent in a couple one day, a few more three days later, a couple more a few days after that. It became apparent they had a population out there."

So Losey and a colleague boarded a plane with their collecting nets and came back to Ithaca with 13 nine-spotted and more than 30 transverse ladybugs.

"Aly was thrilled that people would come all the way from New York to go collecting in our yard," said Kate Yates, who got involved in the project when her daughter saw an ad in the National Wildlife Federation's Ranger Rick magazine for children. "She just had a wonderful time looking for ladybugs, and we were ecstatic when we found some of the nine-spots they were looking for."

The researchers got an overnight shipment of 13 more nine-spots from 40-year-old Sheena Beaverson of Champaign, Ill., who sent in more than 200 ladybug photos while she was staying in Boulder, Colo., for a month.

Searching for ladybugs was a lot like looking for seashells on the beach, said Beaverson, who works for the Illinois State Geological Survey. "At first you look at every single one; later on you start looking for something rare or something special."

Since they arrived at Cornell, the beetles have been busily reproducing inside gossamer net cages lined up in Losey's lab, gorging on juicy green pea aphids raised for them on fava bean plants in the university's greenhouse.

Losey plans to conduct a number of studies with the captive populations in hopes of learning why they declined in the wild.

"The leading theory is that the decline had something to do with ladybugs that were imported," Losey said. "That's mostly based on the timing of the decline, which coincides with the introduction of the seven-spot."

"It does do a lot of good in pest control," Losey said. "The question is whether it just replaced the existing ladybugs or added to the diversity."

The Asian multicolored ladybug, which was released by the U.S. Department of Agriculture in the 1970s and '80s to control scale insects on trees, didn't become widely established until after the natives declined, Losey said. The round Asian beetle is famous for swarming by the thousands on homes on warm autumn days.

"Some of the things we'll look at are, do the native species take longer to develop than the imported ones? Do they not eat as much? Are they more susceptible to parasitoids or pathogens? Did they interbreed and take on the appearance of the seven-spot?" Losey said.

Pest management based on natural predators requires knowledge of the life cycle and feeding habits of the predators.

"The different ladybug species forage different parts of the plant, different parts of the field, at different times of day, and seek different prey," Losey said. "If you want the most effective suppression of pests, you need a whole variety of ladybugs because then they work together and cover different parts of the environment."

Ladybugs eat a wide range of plant-damaging pests, including aphids, mealybugs, scale, and the eggs and young larvae of European corn borers and eastern tent caterpillars.

At some point, field studies will be conducted with the ladybugs being bred in Losey's lab. But it's not a captive breeding program aimed at re-establishing the natives in the wild, he said.

"It could evolve into one, but for now, we're just trying to determine why they declined and what the implications are."

(Agencies)

U.S. astronauts finish maintenance of space station

Astronaut Danny Olivas works outside the International Space Station during his spacewalk in this image from NASA TV September 5, 2009. Olivas and fellow spacewalker European Space Agency astronaut Christer Fuglesang are working to deploy a cargo attachment system and to replace a device designed to help the station determine its position relative to the Earth. (Reuters Photo)

European Space Agency astronaut Christer Fuglesang (L) and astronaut Danny Olivas (Top) work outside the International Space Station during their spacewalk in this image from NASA TV September 5, 2009. Olivas and Fuglesang are working to deploy a cargo attachment system and to replace a device designed to help the station determine its position relative to the Earth. (Reuters Photo)

European Space Agency astronaut Christer Fuglesang exits the airlock in this image from NASA TV September 5, 2009. Fuglesang and fellow spacewalker Danny Olivas scheduled extravehicular activities include the outfitting and maintenance of the International Space Station modules. (Reuters Photo)

European Space Agency astronaut Christer Fuglesang works outside the International Space Station's Qwest airlock in this image from NASA TV September 5, 2009. Fuglesang and fellow spacewalker Danny Olivas are working to deploy a cargo attachment system and to replace a device designed to help the station determine its position relative to the Earth. (Reuters Photo)

WASHINGTON, Sept. 5 (Xinhua) -- Two U.S. astronauts conducted a third and final space walk for shuttle Discovery's STS-128 mission on Saturday and finished outfitting and maintenance of International Space Station modules, NASA said.

According to NASA, Discovery's mission specialists Danny Olivasand Christer Fuglesang began the space walk at 4:39 p.m. EDT (2039 GMT), which lasted over seven hours.

The duo deployed a payload attachment system on the starboard truss and replaced a failed rate gyro assembly, which measures rates for any changes in the station's attitude, with a new one.

With that complete, they split up for the next tasks. Olivas installed a Global Positioning System antenna while Fuglesang replaced a remote power control module and installed an insulation sleeve on a cable inside the truss. Fuglesang followed that up with the installation of a second GPS antenna.

The two then reunited for the final task, routing 60-foot-long avionics systems cables along the station. The cables are being installed in preparation for the arrival of the Node 3 "Tranquility" in 2010.

Discovery lifts off midnight on August 28 from the Kennedy Space Center in Florida after two delays. Its 13-day flight is scheduled to end with a landing back in Florida on Thursday.

Discovery astronauts pack trash, surplus gear for returning home

BEIJING, Sept.7 (Xinhuanet) -- The shuttle Discovery astronauts have almost completed packing up a moving van for return to Earth on Thursday, according to media reports Monday.

The giant van will come back aboard Discovery filled with a ton of trash, surplus gear and completed science experiments after it finished the mission of transferring seven tons of space station supplies and equipment.

The astronauts took a half day off to relax and enjoyed the view on Sunday after a week of virtually nonstop work together.

Astronaut Danny Olivas, who went out on all three spacewalks, said he wanted to gaze out the window and snap some pictures.

"All in all, it's been a very successful mission," Olivas said in a TV interview. "Everybody here is in good spirits, and we are ready to finish up here and come home."

One of the returning spacemen, Timothy Kopra, has been on board the space station since mid-July. He said he'll miss the place, the people, the views, and the 16-daily sunrises and sunsets. But he's looking forward to seeing his wife and two children, "and getting back to life in general on the planet."

Two U.S. astronauts conducted a third and final space walk for shuttle Discovery's STS-128 mission on Saturday and finished outfitting and maintenance of International Space Station modules.

Discovery lifts off midnight on Aug. 28 from the Kennedy Space Center in Florida after two delays. Its 13-day flight is scheduled to end with a landing back in Florida.

(Agencies)

SAARC bio-technology training held in Nepal

KATHMANDU, Sept. 7 (Xinhua) -- A South Asian Association for Regional Cooperation (SAARC) level training began here in Nepali capital Kathmandu Valley on Sunday, local media reported on Monday.

The seven-day training was on use of bio-technology for the prevention of medium scale landslides.

According to Monday's the National News Agency RSS, the training were organized by the Khwopa Engineering College, Research and Development Committee.

There are 27 participants from SAARC countries and are being trained on methods applied to stop landslides in main highways of Nepal, said Convener and Assistant Principal of the College, Deepak Chaulagain.

He informed that experts from Nepal and India will impart training to the participants.

Vietnam to launch 2nd satellite in 2012

HANOI, Sept. 7 (Xinhua) -- Vietnam's Ministry of Information and Communication said that Vietnam expects to launch the second satellite in 2012, the local newspaper Vietnam Investment Review reported Monday.

The state-owned Vietnam Post and Telecommunication (VNPT) is the investor of the project of the second satellite, named Vinasat-2, with a total investment of about 350 million U.S. dollars.

VNPT is considering whether it will launch the satellite by itself or hire other company to do it, said the newspaper.

The second satellite project is to develop satellite facility of Vietnam to meet the growing demand of satellite-based information.

The first satellite of Vietnam, named Vinasat-1, was launched last year, with a total investment of 300 million U.S. dollars.

The Vinasat-1 is currently working at 70 percent of its capacity. It is expected to work at 100 percent of capacity in 2010 and regain investment within nine years.

Snow of Mt Kilimanjaro to disappear in coming decade

The aerial photo taken on Sept. 4, 2009 shows the snowless top of Mount Kilimanjaro. Some scientists warned that the snow caps and glaciers on Mount Kilimanjaro would disappear altogether between 2015 and 2020.(Xinhua/Xu Suhui)

The aerial photo taken on Sept. 4, 2009 shows the snowless top of Mount Kilimanjaro. Some scientists warned that the snow caps and glaciers on Mount Kilimanjaro would disappear altogether between 2015 and 2020.

Astronauts pack trash, surplus gear for ride home

This image provided by NASA shows a portion of the International Space Station photographed by a space walking astronaut during the STS-128 mission's second session of extravehicular activity Thursday Sept. 3, 2009 as construction and maintenance continue on the station. The blackness of space and Earth's horizon provide the backdrop for the scene.(Photo/AP)

CAPE CANAVERAL, Fla. 鈥?The astronauts aboard the linked space shuttle and space station are nearly finished packing up a moving van for return to Earth in a few days.

The Italian-built van 鈥?essentially a giant cylinder 鈥?flew up aboard Discovery with seven tons of space station supplies and equipment. It will come back filled with a ton of trash, surplus gear and completed science experiments.

The astronauts will place the van back aboard Discovery on Monday night, just in time for Tuesday's shuttle undocking.

On Sunday, the 13 space fliers got the night off after a week of virtually nonstop work together. Astronaut Danny Olivas, who went out on all three spacewalks, was looking forward to doing nothing for a change. He said he wanted to gaze out the window and snap some pictures.

"All in all, it's been a very successful mission," Olivas said in a TV interview. "Everybody here is in good spirits, and we are ready to finish up here and come home."

Olivas led the outdoor effort to furnish the international space station with a fresh tank of ammonia coolant and some new antennas and electronic units.

He and a colleague also routed 60 feet of electrical cable for a new room, Tranquility, that's due to arrive early next year. But one of eight cable connectors would not hook up late Saturday night, no matter how hard the spacewalkers tried, and the power jack was left dangling there with an insulating sleeve for protection.

Astronauts on a future shuttle mission will take a crack at fixing the balky connector or rerouting the power for the Tranquility chamber. Tranquility will house life-support systems as well as a lookout tower or cupola, and serve as living quarters.

Earlier this year, Comedy Central's Stephen Colbert campaigned for naming rights to the room and even won NASA's online vote. But the space agency went with Tranquility in honor of this summer's 40th anniversary of the first manned moon landing. It gave the TV comedian's name to a new treadmill that was sent up aboard Discovery.

One of the returning spacemen, Timothy Kopra, has been on board the space station since mid-July. He said he'll miss the place, the people, the views, and the 16-daily sunrises and sunsets. But he's looking forward to seeing his wife and two children, "and getting back to life in general on the planet."

Discovery is due back at Kennedy Space Center on Thursday.

(Agencies)

Great white sharks tagged for first time off Mass.

This image provided by the Massachusets State Division of Marine Fisheries shows a great white shark swimming in the waters near Cape Cod Mass. in Oct. 2004. (Photo/AP)

BOSTON 鈥?Massachusetts officials are using high-tech tags to track the movements of two great white sharks near Cape Cod 鈥?the first time the fearsome fish have ever been tagged in the Atlantic Ocean.

The electronic tag uses satellite technology to record the travels of the sharks, allowing scientists to better understand their migratory patterns.

The sharks were spotted Saturday by scientists investigating sightings off Monomoy Island in Chatham. Officials say a harpooner tagged them with help from a state shark expert.

Sharks are common in Cape waters during summer, though great white sharks are relatively rare around New England.

State officials have warned area swimmers to be on the lookout for sharks this weekend, and state environmental police are patrolling the area as a precaution.

(Agencies)

NY researchers give ladybugs a birds-and-bees talk

ITHACA, N.Y. 鈥?A year after they launched a nationwide search for dwindling native ladybugs, New York researchers are breeding colonies of them from insects found by citizen scientists in Oregon and Colorado.

Cornell University entomologist John Losey launched the Lost Ladybug Project to figure out why common native ladybug species had all but disappeared.

This summer, the researchers collected native nine-spotted and transversa ladybugs found by participants and started breeding them in the lab. They hope to shed light on why they've become so scarce.

The leading theory is that the decline was related to the release of non-native species for crop pest control decades ago. The European seven-spot and Asian multicolored ladybugs have become the dominant species.

(Agencies)

Astronauts work outside Int'l Space Station

Astronaut Danny Olivas works outside the International Space Station during his spacewalk in this image from NASA TV Sept. 5, 2009. Olivas and fellow spacewalker European Space Agency astronaut Christer Fuglesang are working to deploy a cargo attachment system and to replace a device designed to help the station determine its position relative to the Earth. (Reuters Photo)

European Space Agency astronaut Christer Fuglesang (L) and astronaut Danny Olivas (Top) work outside the International Space Station during their spacewalk in this image from NASA TV September 5, 2009. Olivas and Fuglesang are working to deploy a cargo attachment system and to replace a device designed to help the station determine its position relative to the Earth.(Reuters Photo)

European Space Agency astronaut Christer Fuglesang exits the airlock in this image from NASA TV September 5, 2009. Fuglesang and fellow spacewalker Danny Olivas scheduled extravehicular activities include the outfitting and maintenance of the International Space Station modules.(Reuters Photo)

European Space Agency astronaut Christer Fuglesang works outside the International Space Station's Qwest airlock in this image from NASA TV September 5, 2009. Fuglesang and fellow spacewalker Danny Olivas are working to deploy a cargo attachment system and to replace a device designed to help the station determine its position relative to the Earth.(Reuters Photo)

Astronaut Danny Olivas works outside the International Space Station during his spacewalk in this image from NASA TV Sept. 5, 2009.

Olivas and fellow spacewalker European Space Agency astronaut Christer Fuglesang are working to deploy a cargo attachment system and to replace a device designed to help the station determine its position relative to the Earth.

Large amphibious rescue aircraft on drawing board

WUHAN, Sept. 7 (Xinhua) -- China has begun work on building a large amphibious aircraft for fire fighting and rescue missions, an official from Aviation Industry Corporation of China (AVIC) confirmed Monday.

When completed, they will be the first aircraft of their type manufactured in China.

The start of research work was announced Saturday at AVIC' s China Special Aircraft Institute (also known as Institute 605 of AVIC) which is based in Jinmen City in central China's Hubei Province, said an official who requested anonymity.

Chen Zhengguo, the institute's designer in- chief for the research program, said the machine would be a four-engine propeller aircraft able to touch down on land and water. It would have a maximum take-off weight of 49 tonnes.

The aircraft would be able to touch down and glide to draw water for fire-fighting purposes, with a maximum water-carrying capacity of 12 tonnes, said Chen.

The machine will also be equipped with first aid equipment and would be able to provide a rescue service for up to 50 people a time.

Market research shows that demand for this type of aircraft in the domestic market would be 50 in the near future and rise to 150in the next 15 years.

The building schedule calls for the aircraft's first prototype to be ready for its maiden flight in 2013 and for it to obtain a civil aviation certificate from China's air authority the year after.

Russia to start construction on new space center in 2011

MOSCOW, Sept. 7 (Xinhua) -- Russia will begin to build a new space center in its far east in 2011, a government official said Monday.

The three-stage construction project for the new Vostochny station will be completed in 2018, said Army General Nikolai Abroskin, head of the Federal Service for the Production of Special Construction Work.

"In all, seven launch pads are to be built at the space center, including two for manned flights and two for space freighters," the RIA Novosti news agency quoted the official as saying.

Russia now uses two centers to launch carrier rockets and conduct ballistic missile tests: the Baikonur space center in Kazakhstan and the Plesetsk space center in northwest Russia.

Scientists discover giant rats, fanged frogs, grunting fish

BEIJING, September 7 (Xinhuanet) -- Scientists and filmmakers have discovered a new species of giant rat deep in the jungle of Papua New Guinea along with other other animals hitherto unseen.

The woolly rat, an over-sized vegetarian rodent, measures 82 cm long and weighs in at 1.5 Kg. Its size makes it amongst the largest species of rat known anywhere in the world.

The creature was discovered by an expedition team filming for BBC program Lost Land of the Volcano.

But the large rat is only one of dozens of new creatures found in the shadow of the Bosavi volcano. The team also found scores of strange spiders and around 20 species of insect.

"Highlights include a camouflaged gecko, a fanged frog and a fish called the Henamo Grunter, so named because it makes grunting noises from its swim bladder," Steve Greenwood, series producer for Lost Land of the Volcano, said. The fanged frog is only one of some 16 new frogs discovered.

The area in which the animals were found is particularly inaccessible and the team spent several weeks scaling the 2,800 meter summit with the help from local trackers.

(Agencies)

"Liposuction leftovers" easily converted to iPS cells, U.S. study shows

WASHINGTON, Sept. 8 (Xinhua) -- Globs of human fat removed during liposuction conceal versatile cells that are more quickly and easily coaxed to become induced pluripotent stem cells, or iPS cells, than are the skin cells most often used by researchers, according to a new study from Stanford's School of Medicine. The findings were published online Monday in the Proceedings of the National Academy of Sciences.

"We've identified a great natural resource," said Stanford surgery professor and co-author of the research, Michael Longaker, who has called the readily available liposuction leftovers "liquid gold." Reprogramming adult cells to function like embryonic stem cells is one way researchers hope to create patient-specific cell lines to regenerate tissue or to study specific diseases in the laboratory.

"Thirty to 40 percent of adults in this country are obese," agreed cardiologist Joseph Wu, the paper's senior author. "Not only can we start with a lot of cells, we can reprogram them much more efficiently. Fibroblasts, or skin cells, must be grown in the lab for three weeks or more before they can be reprogrammed. But these stem cells from fat are ready to go right away."

Longaker is the deputy director of Stanford's Stem Cell Biology and Regenerative Medicine Institute and director of children's surgical research at Lucile Packard Children's Hospital. Wu is an assistant professor of cardiology and radiology, and a member of Stanford's Cardiovascular Institute.

The fact that the cells can also be converted without the need for mouse-derived "feeder cells" may make them an ideal starting material for human therapies. Feeder cells are often used when growing human skin cells outside the body, but physicians worry that cross-species contamination could make them unsuitable for human use.

Even those of us who are not obese would probably be happy to part with a couple of pounds (or more) of flab. Nestled within this unwanted latticework of fat cells and collagen are multipotent cells called adipose, or fat, stem cells. Unlike highly specialized skin-cell fibroblasts, these cells in the fat have a relatively wide portfolio of differentiation options -- becoming fat, bone or muscle as needed. It's this pre-existing flexibility, the researchers believe, that gives these cell an edge over the skin cells.

"These cells are not as far along on the differentiation pathway, so they're easier to back up to an earlier state," said first author and postdoctoral scholar Ning Sun, who conducted the research in both Longaker's and Wu's laboratories. "They are more embryonic-like than fibroblasts, which take more effort to reprogram."

These reprogrammed iPS cells are usually created by expressing four genes, called Yamanaka factors, normally unexpressed (or expressed at very low levels) in adult cells.

Sun found that the fat stem cells actually express higher starting levels of two of the four reprogramming genes than do adult skin cells -- suggesting that these cells are already primed for change. When he added all four genes, about 0.01 percent of the skin-cell fibroblasts eventually became iPS cells but about 0.2 percent of the fat stem cells did so -- a 20-fold improvement inefficiency.

The new iPS cells passed the standard tests for pluripotency: They formed tumors called teratomas when injected into immunocompromised mice, and they could differentiate into cells from the three main tissue types in the body, including neurons, muscle and gut epithelium. The researchers are now investigating whether the gene expression profiles of the fat stem cells could be used to identify a subpopulation that could be reprogrammed even more efficiently.

"The idea of reprogramming a cell from your body to become anything your body needs is very exciting," said Longaker. "The field now needs to move forward in ways that the Food and Drug Administration would approve -- with cells that can be efficiently reprogrammed without the risk of cross-species contamination -- and Stanford is an ideal place for that to happen."

"Imagine if we could isolate fat cells from a patient with some type of congenital cardiac disease," said Wu. "We could then differentiate them into cardiac cells, study how they respond to different drugs or stimuli and see how they compare to normal cells. This would be a great advance."

Genomes reveal bacterial lifestyles: research

WASHINGTON, Sept. 7 (Xinhua) -- Sampling just a few genes can reveal not only the "lifestyle" of marine microbes but of their entire environments, new research suggests.

The finding means researchers may be able to predict the types of microbes that thrive in specific marine environments by sampling the genomes of just a few dominant species, according to research co-author Rick Cavicchioli of the University of New South Wales (UNSW). As well, it may reveal new insights into the impacts of climate change on biodiversity in the world's oceans. The findings are published Monday in the Proceedings of the National Academy of Sciences.

"It's a bit like using the DNA from a single hair at a crime scene to discover the identity of the perpetrator," says Professor Cavicchioli. "What we've learned here is that a few genes can tell us a much about the nature of the environment that species come from and what influences them to evolve in a specific way."

With other UNSW and U.S. colleagues, Professor Cavicchioli compared the genomes of two common ocean bacteria that employ different strategies for living: one lives in nutrient-rich waters and is fast to grow and replicate itself, and another lives in poor-nutrient waters, and grows more slowly.

The comparison revealed genetic differences that reflect the different lifestyles of the two species: the bacteria from the nutrient-rich waters have many selective transporter proteins to quickly absorb plentiful nutrients while those from nutrient-poor waters have a smaller number of highly efficient transporter proteins to extract what little nutrition is available.

Differences in other genes were also identified concerning nutrient and energy usage and resistance to infecting viruses, which reflect the bacteria's adaptations to their environment. Armed with such knowledge from a few key genes, it should be possible to predict what sort of environment an individual species evolved in, says Professor Cavicchioli. Better still, sampling the genomes of a small number of species should enable scientists to gain useful new insights into the dynamics of whole marine ecosystems.

"It's not practical to sample every species in a given area so the model we have described is useful for studying the collective genomes of whole marine microbial communities -- or metagenomes --to better understand how they have evolved in specific locations," he says.

"By analyzing and comparing the strategies of the dominant organisms we should have an idea of the carbon flux going through the environment which will allow us to monitor the health of the marine ecosystem, including the impact of global warming," he says." The analysis, for example, may help us predict how marine bacteria will respond to environmental changes caused by climate change, such as oceans becoming warmer or absorbing more carbon dioxide from the atmosphere and becoming more acidic."

Using their new technique to analyze 124 ocean bacteria, the researchers found that bacteria adapted to low nutrients outnumber bacteria adapted to high nutrients in worldwide samples of ocean water. This has led to an under-reporting on what is known about the biodiversity and the physiological properties of the more abundant bacteria -- and what secrets they may reveal about life on earth.

Infections may lead to faster memory loss in Alzheimer's disease: research

WASHINGTON, Sept. 7 (Xinhua) -- Getting a cold, stomach bug or other infection may lead to increased memory loss in people with Alzheimer's disease, according to research to be published Tuesday in Neurology, the medical journal of the American Academy of Neurology.

The study found that people who had respiratory, gastrointestinal or other infections or even bumps and bruises from a fall were more likely to have high blood levels of tumor necrosis factor-alpha, a protein involved in the inflammatory process, and were also more likely to experience memory loss or other types of cognitive decline than people who did not have infections and who had low levels of the protein.

The blood levels and cognitive abilities of 222 people with Alzheimer's disease with an average age of 83 were measured at the beginning of the study and three more times over six months. Caregivers were interviewed to determine whether the participants had experienced any infections or accidental injury that could lead to inflammation.

A total of 110 people experienced an infection or injury that led to inflammation during the study. Those people experienced memory loss that was at twice the rate of those who did not have infections or injuries.

People who had high levels of the protein in their blood at the beginning of the study, which may indicate chronic inflammation, had memory loss at four times the rate of those with low levels of the protein at the start of the study. Those who had high levels of the protein at the start of the study who also experienced acute infections during the study had memory loss at 10 times the rate of those who started with low levels and had no infections over the six-month period.

"One might guess that people with a more rapid rate of cognitive decline are more susceptible to infections or injury, but we found no evidence to suggest that people with more severe dementia were more likely to have infections or injuries at the beginning of the study," said study author Clive Holmes, of the University of Southampton in the United Kingdom.

"More research needs to be done to understand the role of tumor necrosis factor-alpha in the brain, but it's possible that finding a way to reduce those levels could be beneficial for people with Alzheimer's disease."

Researchers find first evidence of virus in malignant prostate cells

WASHINGTON, Sept. 7 (Xinhua) -- In a finding with potentially major implications for identifying a viral cause of prostate cancer, researchers at the University of Utah and Columbia University medical schools have reported that a type of virus known to cause leukemia and sarcomas in animals has been found for the first time in malignant human prostate cancer cells.

If further investigation proves the virus, XMRV (Xenotropic murine leukemia virus-related virus), causes prostate cancer in people, it would open opportunities for developing diagnostic tests, vaccines, and therapies for treating the cancer, according to the study published Monday online in the Proceedings of the National Academy of Sciences.

Prostate cancer is expected to strike nearly 200,000 U.S. males this year, making it the second most common form of cancer, outside of skin cancers, among men.

"We found that XMRV was present in 27 percent of prostate cancers we examined and that it was associated with more aggressive tumors," said Ila R. Singh, associate professor of pathology at University of Utah and the study's senior author. "We still don't know that this virus causes cancer in people, but that is an important question we're going to investigate."

Along with providing the first proof that XMRV is present in malignant cells, the study also confirmed that XMRV is a gamma retrovirus, a simple retrovirus first isolated from prostate cancers in 2006 by researchers at the University of California, San Francisco (UCSF), and the Cleveland Clinic.

Gamma retroviruses are known to cause cancer in animals, but have not been shown to do so in humans. The UCSF study did not examine benign (non-malignant) prostate tissues, so could not linkXMRV to prostate cancer. They also did not find the virus in malignant cells.

Singh and her fellow researchers examined more than 200 human prostate cancers, and compared them to more than 100 non-cancerous prostate tissues. They found 27 percent of the cancers contained XMRV, compared to only 6 percent of the benign tissues. The viral proteins were found almost exclusively in malignant prostatic cells, suggesting that XMRV infection may be directly linked to the formation of tumors.

Retroviruses insert a DNA copy of their genome into the chromosomes of the cells they infect. Such an insertion sometimes occurs adjacent to a gene that regulates cell growth, disrupting normal cell growth, resulting in more rapid proliferation of such a cell, which eventually develops into a cancer. This mechanism of carcinogenesis is followed by gammaretroviruses in general. Singh is currently examining if a similar mechanism might be involved with XMRV and prostate cancer.

In another important finding of the study, Singh and her colleagues also showed that susceptibility to XMRV infection is not enhanced by a genetic mutation, as was previously reported. IfXMRV were caused by the mutation, only the 10 percent of the population who carry the mutated gene would be at risk for infection with virus. But Singh found no connection between XMRV and the mutation, meaning the risk for infection may extend to the population at large.

While the study answers important questions about XMRV, it also raises a number of other questions, such as whether the virus infects women, is sexually transmitted, how prevalent it is in the general population, and whether it causes cancers in tissues other than the prostate.

"We have many questions right now," Singh said, "and we believe this merits further investigation."

Viruses have been shown to cause cancer of the cervix, connective tissues (sarcomas), immune system (lymphoma), and other organs. If the retrovirus is shown to cause prostate cancer, this could have important implications for preventing viral transmission and for developing vaccines to prevent XMRV infection in people.

Scientists make ICub robot capable of learning

Peter Ford Dominey, CNRS Director of Research, poses with ICub robot, a ybrid embodied cognitive system for a humanoid robot" about 1 metre (3.2 feet) high, at the INSERM institute in Bron, near Lyon, southeastern France, August 31, 2009. Six versions of ICub exist in laboratories across Europe, where scientists are painstakingly tweaking its electronic brain to make it capable of learning, just like a human child and hoping it will learn how to adapt its behaviour to changing circumstances, offering new insights into the development of human consciousness. Picture taken August 31, 2009.(Reuters Photo)

Peter Ford Dominey, CNRS Director of Research, makes a demonstration with ICub robot, a ybrid embodied cognitive system for a humanoid robot" about 1 metre (3.2 feet) high, at the INSERM institute in Bron, near Lyon, southeastern France, August 31, 2009. Six versions of ICub exist in laboratories across Europe, where scientists are painstakingly tweaking its electronic brain to make it capable of learning, just like a human child and hoping it will learn how to adapt its behaviour to changing circumstances, offering new insights into the development of human consciousness. Picture taken August 31, 2009.(Reuters Photo)

ICub robot, a ybrid embodied cognitive system for a humanoid robot" about 1 metre (3.2 feet) high, moves it arms and legs during a demonstration at the INSERM institute in Bron, near Lyon, southeastern France, August 31, 2009. Six versions of ICub exist in laboratories across Europe, where scientists are painstakingly tweaking its electronic brain to make it capable of learning, just like a human child and hoping it will learn how to adapt its behaviour to changing circumstances, offering new insights into the development of human consciousness. Picture taken August 31, 2009.(Reuters Photo)

ICub robot, a ybrid embodied cognitive system for a humanoid robot" about 1 metre (3.2 feet) high, makes a phone call during a demonstration at the INSERM institute in Bron, near Lyon, southeastern France, August 31, 2009. Six versions of ICub exist in laboratories across Europe, where scientists are painstakingly tweaking its electronic brain to make it capable of learning, just like a human child and hoping it will learn how to adapt its behaviour to changing circumstances, offering new insights into the development of human consciousness, no less. Picture taken August 31, 2009. (Reuters Photo)

Peter Ford Dominey, CNRS Director of Research, poses with ICub robot, a ybrid embodied cognitive system for a humanoid robot" about 1 metre (3.2 feet) high, at the INSERM institute in Bron, near Lyon, southeastern France, August 31, 2009.

In tiny 'Tuk,' they man climate's front line

This July 24, 1996 photo released by the Government of Northwest Territories shows the Canadian Arctic community of Tuktoyaktuk in the Northwest Territories, Canada. (Photo/AP)

TUKTOYAKTUK, Northwest Territories 鈥?Caught between rising seas and land melting beneath their mukluk-shod feet, the villagers of Tuktoyaktuk are doing what anyone would do on this windy Arctic coastline. They're building windmills.

That's wind-power turbines, to be exact 鈥?a token first try at "getting rid of this fossil fuel we're using," said Mayor Merven Gruben.

It's a token of irony, too: People little to blame, but feeling it most, are doing more to stop global warming than many of "you people in the south," as Gruben calls the rest of us who fill the skies with greenhouse gases.

They're feeling climate change not only in this lonely corner of northwest Canada, but in a wide circle at the top of the world, stretching from Alaska through the Siberian tundra, into northern Scandinavia and Greenland, and on to Canada's eastern Arctic islands, a circle of more than 300,000 indigenous people, including Gruben and the 800 other Inuvialuit, or Inuit, of the village they know as "Tuk."

Since 1970, temperatures have risen more than 2.5 C (4.5 F) in much of the Arctic, much faster than the global average. People in Tuk say winters are less numbing, with briefer spells of minus-40 C (minus-40 F) temperatures. They sense it in other ways, too, small and large.

"The mosquitoes got bigger," the mayor's aunt, Tootsie Lugt, 48, told a visitor to her children-filled house overlooking Tuk harbor.

Her father, one-time fur trapper Eddie Gruben, spoke of more outsized interlopers from the south.

"Them killer whales, first time people seen them here in the harbor, three or four of them this summer," said the 89-year-old patriarch of Tuk's biggest family and biggest business, a contracting firm.

Plants and animals are a tip-off everywhere. In northeast Canada, the Nunatsiaq News advised readers the red-breasted birds they spotted this spring were American robins.

But the change runs deeper as well, undermining ways of life.

The later fall freeze-up, earlier spring break-up and general weakening of sea ice make snowmobile travel more perilous. A trip to the next island can end in a fatal plunge through thin ice.

The unpredictable ice and weather combine with a changing animal world to make hunting and fishing more challenging, and to crimp the traditional diet of "niqituinnaq," "real food" 鈥?of caribou, seal and other meat staples.

The resilient Inuit 鈥?Eskimos 鈥?of the past simply moved on to better places. But since the mid-20th century these ex-nomads have been tied to settlements, with all the buildings, utilities, roads and trouble that represents in a warming world.

At Tuk's graveyard, for example, white crosses stand akilter where the permafrost has heaved and sunk below. "In another 20 years I'll be burying my relatives again," Gus Gruben, 45, the mayor's brother, said sadly as he surveyed the graves of forebears which will someday have to be moved.

Just meters (yards) away, the sound of Tuk eroding could be heard: The steel-gray Arctic Ocean crashed against a beach barrier of small boulders.

The hamlet of Tuktoyaktuk grew up in the 20th century on a spit of gravelly land hooking out into the Arctic's Beaufort Sea, at latitude 69 degrees north, 2,500 kilometers (1,500 miles) from the U.S. border, beyond the continent's treeline and amid a tundra landscape of numberless lakes framed by drier land overlaid with moss, lichens and shrubs.

Today's Tuk is a jumble of homely wood-frame houses, in white or pale blue or red, beneath power lines that sag alongside dirt roads leading to the peninsula's tip, "The Point," just past Our Lady of Grace church. The little chapel of peeling white paint and a doorway topped by the proud antlers of a long-ago caribou buck.

Like much of the western Arctic coast, the land here has been sinking for centuries, an aftereffect of the Ice Age. In recent memory, before stopgap barriers were built, the sea each year was taking away about a meter (3 feet) of Tuk's beach. Gus Gruben remembers waves spraying through classroom windows in the 1970s, before the school was moved from its spot near the graveyard.

Climate change now adds to the problem.

Much of the "land" is ice, great wedges of it stuck in the frozen soil of the permafrost. Rising temperatures mean thawing tundra, and that means sinking terrain, making Tuk even more vulnerable to the battering of the sea.

Steve Solomon, a government coastal geologist who has long studied Tuktoyaktuk's predicament, said the combination of land subsidence and seas rising from global warming add up to Tuk's "sinking" by 3 millimeters (an eighth of an inch) a year.

That translates into bigger numbers for shore erosion in key spots, like Tuktoyaktuk Island, whose 10-meter (30-foot) cliffs protect the harbor mouth.

"Tuktoyaktuk Island is completely unprotected, exposed," Solomon said from his Nova Scotia office. "It's eroding at 2 meters (yards) a year."

Warming ocean waters are undercutting the cliffs' permafrost base. Solomon believes that at current erosion rates 鈥?and they may worsen as warming does 鈥?the island will be reduced to a small shoal in 30 or 40 years, exposing the unprotected side of Tuk's populated peninsula to ocean waves.

The heart of town already must deal with permafrost melt, as houses on shallow supports shift and tilt on a slowly liquefying base.

"Every house has a problem eventually," said Merven Gruben. The mayor's brother Gus believes "someday we'll all have to move to Reindeer Point," a cluster of houses on higher ground 3 miles inland, begun in the 1990s. But Merven scoffs, "It's too far out. Siberia, they call it."

Reindeer Point resident Nellie Pokiak, 55, concedes people are relucant. "Tuk's population's growing," she said. "But it's hard to see them moving from their traditional fishing areas," old homes with small boats backing on the harbor. "That's where Tuk began."

Tuk has a problem, too, with what the mayor calls "our submersible roads," flooded by seawater more and more often when storms sweep in from the west. Villagers worry that the sea will soon flood a large old dump, filled with the U.S. military's trash when it operated a radar station here, and spread its contaminants on and off shore.

The gravel is washing away at The Point, meanwhile. At least 20 buildings are directly threatened by the shore erosion. And Tuk's vital truck link to the south, a 180-kilometer (110-mile) "ice road" marked out each winter over the frozen sea and up the frozen Mackenzie River, will have shorter safe-driving seasons.

Tuk's troubles are repeated in settlements across the Arctic. Some examples:

_On Alaska's Bering and Chukchi sea coasts, villages may have to be relocated. The U.S. Army and Marines are already helping the 350 people of one hamlet, Newtok, move to higher ground.

_Across the Bering Strait in east Siberia, thawing permafrost has damaged airport runways, cutting off communities from emergency medical evacuations, a representative of the indigenous Yukagir people told an Anchorage conference this May.

_In Pangnirtung, on Canada's Baffin Island, an unusual rush of meltwater this spring eroded the permafrost holding up two bridges, bringing them down.

The sturdy, trim great-grandfather Eddie Gruben remembered better, colder times, as he sat on his daughter's sofa, beneath an enlarged photo of himself a half-century ago, leading a dogsled team on a polar bear hunt.

"Even in the ocean today the ice isn't getting thick like it used to be," the old hunter said. "Thirty, 40 years ago, in June it was still solid ice. Now the first week in June there's no ice. It used to be a long winter."

His grandson the mayor hopes Tuk will sit tight for many more winters.

That's why he and the hamlet council agreed to the wind-power plan, a government project to test the technology in this harsh environment. Two to four turbines are expected to be operating by 2011, replacing perhaps 20 percent of Tuk's current diesel-generated power, as this little place does its part to reduce emissions blamed for global warming.

The pylons will pierce the Arctic skyline along with the automated radar tower the Americans left behind in 1994, after decades in which Tuktoyaktuk served as a link in the manned DEW 鈥?Distant Early Warning 鈥?line.

Now, rather than alert America to nuclear attack, Tuk may serve as an early warning post for a warming planet.

The 47-year-old mayor believes there's still time for "the people in the south" to take global action to stem the worst of warming. "I'm hopeful," Merven Gruben said. "I don't think it's too late."

Except, perhaps, for Tuk.

The community is gradually "moving south," he said, placing its newest structures farther from the worst erosion. "Eventually we have to move," said the bear hunter's grandson. "It's a losing battle."

(Agencies)

Astronauts pack Buzz Lightyear for ride home

In this image made from video provided by NASA, the space station's newest resident Nicole Scott holds a camera before the hatches between the orbiting shuttle and station close Monday Sept. 7, 2009. The shuttle will undock Tuesday.(Photo/AP)

CAPE CANAVERAL, Fla. 鈥?The astronauts aboard the orbiting shuttle and station packed up Buzz Lightyear on Monday for the ride home from "infinity and beyond."

The 12-inch action figure has been at the international space station for more than a year.

Mission Control asked Discovery's crew to do a final check to make certain Buzz was safely stowed on the shuttle, before the hatches between the linked spacecraft were sealed late Monday night. The shuttle will depart Tuesday.

NASA also was tracking another threatening piece of space junk, but did not think the orbiting outpost would have to steer clear.

The Buzz Lightyear toy kept a relatively low profile at the space station following its June 2008 arrival, but was pulled out for extensive filming over the past week. Some of the movie scenes: Buzz going to sleep with an astronaut who lets go, causing the doll to float away and hit a wall, and Buzz flying through a chamber followed by a real spaceman.

NASA said the video will be used in an educational outreach effort for children and have a "Toy Story" movie spin.

As for Buzz, a Walt Disney World spokesman said the toy will take part in "several debriefing sessions" and then a ticker tape parade with Apollo 11 moonwalker Buzz Aldrin at the beginning of October. The spokesman said Buzz has become "the longest serving astronaut in space."

Late Monday, the 13 human astronauts accomplished one last major job together before parting company.

A moving van holding a ton of trash and discarded equipment was moved back aboard Discovery, with the use of a hefty robot arm. The van was delivered by the shuttle, fully loaded with supplies, and moved onto the international space station one week ago.

The two crews 鈥?seven on the shuttle and six on the station 鈥?hugged and shook hands as they said goodbye. "Have a safe trip and have a safe landing, guys," said the station's skipper, Russian Gennady Padalka.

Meanwhile, the latest piece of menacing space debris is from a Chinese satellite blasted by a missile in a 2007 test. It was expected to fly near the space station early Wednesday.

Flight director Tony Ceccacci did not know the size of the fragment, but he noted that early projections put the closest approach at 15 miles. A massive piece of an old rocket passed less than a mile from the shuttle-station complex Friday, but required no dodging.

In a series of Labor Day interviews, shuttle astronaut Jose Hernandez said his presence in space "means hope for all our people that speak Spanish." He grew up in a migrant worker family from Mexico.

"If you work hard and study hard, any dream can be achieved," Hernandez said in Spanish, "and I am the proof of that because I started (with) very little means."

The space station's new resident, Nicole Stott, said she's looking forward to gazing down at her home state of Florida and the rest of the planet over the next three months. She took up a watercolor kit to paint what she sees.

She said the artwork might not be that good, "but it will certainly be fun for me to try."

Stott flew up on Discovery as the replacement for Timothy Kopra, who has been in orbit since mid-July. Kopra will return to Earth on Thursday, along with the six other shuttle astronauts and, of course, Buzz.

(Agencies)

Post-wildfire worries: floods, damaged ecosystem

LOS ANGELES 鈥?Southern California's huge wildfire has turned nearly a quarter of the 1,000-square-mile Angeles National Forest into a moonscape of barren mountains looming above thousands of homes that now face the threat of flash floods and mudslides.

Experts are already evaluating the extent of risk to lives and property as well as the impacts of the wildfire on a forest ecosystem that in some areas may not have burned in at least a century.

Sprawled across the San Gabriel Mountains, the Angeles is both a playground for millions in greater Los Angeles and a true wilderness ranging from arid desert to alpine forests and peaks topping 10,000 feet. Skiers dare its steeps in winter; bears wander out of its chaparral cloak in summer for dips in suburban pools.

The chief concern is the impact the 246-square-mile Station Fire is having on the watershed. Countless canyons, ravines and gullies funnel watercourses toward communities at the forest's edge.

The Los Angeles County Department of Public Works maintains a legendary flood-control system including 14 major dams, 500 miles of open storm channel and a nearly 3,000-mile network of underground storm drains capable of carrying storm water and debris through the metropolitan region to the ocean.

The system also includes basins 鈥?30 to 40 in the area impacted by the fire 鈥?that intercept debris-laden flows from the canyons and trap mud and vegetation before the water continues on.

"Our concerns are that we will have a larger quantity of debris than normal being captured by our flood control system and, primarily, that individual property owners may be impacted by mudslides or mudflows to their properties," said Mark Pestrella, public works deputy director.

An overall assessment to predict the water flow has already begun. The basins are being examined to determine how much they may need to be cleaned out to create capacity, and channels are being examined to make sure they are free of obstruction such as overgrowth, Pestrella said.

That work will be done by Oct. 15, which the department marks as the start of the storm season, he said.

Teams will also fan out to assess burned slopes to warn homeowners and determine if temporary structures need to be built.

In Big Tujunga Canyon, Joseph Stachura can already see the danger: The fire left boulders unsupported on a barren slope above his home.

"That's pretty scary," he said. "I'm going to have to send the wife and kids out again when it rains because there's a good chance this hillside is going to move."

Rocks have already fallen on forest roads.

Although the Station Fire is now the biggest in county history, each element of the flood-control system was engineered for its portion of the watershed and has been tested by previous fires, Pestrella said.

"The system is nearing 100 years old and it has quite a track record for performing during these kind of events," he said.

The biggest defense against disastrous flooding this winter may be the weather trend.

On June 30, most of southwestern California completed its fourth consecutive season of below-normal rainfall. Precipitation in downtown Los Angeles has been only 64 percent of normal in those years, according to the National Weather Service.

The region is in for more of the same, said Bill Patzert, the veteran Jet Propulsion Laboratory scientist who investigates how climate variation is linked to oceans, including the El Nino warming phenomenon that sometimes leads to dramatically heavy rains in California.

The current El Nino "is definitely wimping out on us," Patzert said.

"The dice are definitely loaded. When you have a weak El Nino or a disappearing El Nino, it's a below-normal rainfall year," he said.

Patzert cautioned that it doesn't take an El Nino to bring heavy rains and the full picture of the risk the region will face from winter rains won't be known until after the fall 鈥?the major fire season in Southern California. He is certain there's trouble enough already.

"Any kind of rain is going to be a mess," he said.

In the forest, the consequences of the fire range from loss of wildlife and habitat to an indefinite closure of a vast area used for hiking, fishing, hunting, mountain biking and even commuting.

For the thousands of hikers, much of the forest may no longer resemble the descriptions in "Trails of the Angeles," the bible for trekkers in the San Gabriels since the early 1970s.

"I think you have a hard time designing a more destructive fire from a hiker's standpoint," said Doug Christiansen, now co-author of the guide originated by John W. Robinson. "All that country that it took out contains some of the most heavily used ... and some of the oldest hiking trails on the mountain range."

Christiansen said he and his wife hiked in the Angeles a few days before the fire.

"I feel like that was probably my last glimpse of the mountain range as I knew it. It's going to be generations before it comes back," he said.

County health authorities, meanwhile, are warning people to keep themselves and pets away from any wildlife that may have been forced out of the forest.

There's no doubt the massive fire killed off "thousands and thousands" of animals, mostly small mammals that could not escape the flames, said Pepperdine University biologist Lee Kats, who has investigated the impact of wildfires on wildlife.

"We have some animals that don't have the best escape mechanism. While birds and larger animals can certainly flee, a lot of smaller ones can't," Kats said.

Of particular concern are rodents, reptiles and raccoons 鈥?animals that don't get a lot of attention, but play an important role in forest wildlife diversity.

Scientists say it is too early to know what kind of long-term damage the Station Fire wrought on the forest ecosystem. Chaparral generally is highly adapted to a fire-prone environment.

But researchers are concerned that if chaparral burns too often, invasive weeds and flammable grasses could crowd out native shrubs, transforming the landscape.

"If we end up with these areas burning again in a couple of years for whatever reason, then you can end up actually changing native vegetation to exotic vegetation," said Travis Longcore, research associate professor of geography at the University of Southern California.

Many ecosystems can bounce back from devastating fires as long as the blazes are not frequent.

"The reality is there have been fires in the past and there will be fires in the future. Unless you want to pave the mountain, we have to accept that fact," said Longcore, who is also the science director of the nonprofit Urban Wildlands Group.

Jon Keeley, a research ecologist with the U.S. Geological Survey's Western Ecological Research Center, said burned areas should sprout without trouble since they haven't faced repeated fires, and recovery is likely to be very quick.

"Next spring, assuming we get reasonable rain, most of those hills should be green with regrowth," Keeley said.

He said the forest will also see an increased diversity of native plants since many seeds lie dormant in the soil waiting for a fire to pass through in order to grow.

(Agencies)

New ISS crew takes final tests before flight

MOSCOW, Sept. 8 (Xinhua) -- The crew members of a new mission to the International Space Station (ISS) started their final tests at a space training center near Moscow Tuesday, news reports said.

During the two-day exams, Russian cosmonaut Maxim Surayev, U.S. astronaut Jeff Williams and their backup crew members will take tests on a ground simulator of the Russian segment of the ISS and on a Soyuz spacecraft simulator.

Canadian billionaire Guy Laliberte, founder and CEO of the world-renowned acrobatic group Cirque du Soleil, will join the mission as a space tourist if he passes the exams.

A special commission will announce the final list of the crew on Thursday.

The mission is scheduled to leave for the ISS in the Soyuz TMA-16 spacecraft on Sept. 30.

Turkey to launch first domestic earth observation satellite

ANKARA, Sept. 8 (Xinhua) -- Turkey plans to launch its first domestically-built earth observation satellite next year, the semi-official Anatolia news agency reported Tuesday.

The satellite, which is called Rasat with a high-resolution optical imaging system and new modules developed by Turkish engineers, will be the first earth observation satellite to be designed and manufactured in Turkey, said the report.

Images from Rasat are expected to be used for such purposes as mapping, disaster monitoring and urban planning, according to the report.

The satellite will be launched from an airlift base in southeast Russia, the report said.

Officials of the Space Technologies Research Institute of Turkey's Scientific and Technological Research Council and Russia's International Space Company Kosmotras inked a deal last month for the launch of the Turkish satellite, it said.

US firm wins huge solar power project in China

File photo of a Chinese man showing solar panels that supply power and hot water on the roof of his building in Shanghai. US energy giant First Solar on Tuesday won a deal to build the world's largest solar power plant in China, aimed at helping mitigate climate change concerns.(Photo/AFP)

WASHINGTON 鈥?US energy giant First Solar won a deal with China to build the world's largest solar power plant in the Mongolian desert which officials say could mitigate climate change concerns.

First Solar will construct the two-gigawatt plant in Ordos City, Inner Mongolia, under a memorandum of understanding (MOU) inked Tuesday with Chinese officials at the company's headquarters in Tempe, Arizona.

The solar facility is to be built in four phases over a decade and supply power to three million Chinese homes, the company said in a statement.

"We're proud to be announcing this precedent-setting project today," First Solar chief executive Mike Ahearn said in the statement.

The United States and China, he said, could work together to reduce the cost of solar electricity to "grid parity" -- where it is competitive with traditional energy sources -- and "create the blueprint for accelerated mass-scale deployment of solar power worldwide to mitigate climate change."

The financial terms of the deal were not disclosed but First Solar said that if a similar plant were to be built in the United States, the cost would be about five to six billion dollars.

"In China, due to lower labor costs and other factors, we expect the plant cost would likely be lower," Lisa Morse, First Solar spokeswoman.

"We are not speculating on what the actual cost of a plant might be in China since details of the project still have to be determined," she said.

China's chief legislator, Wu Bangguo, the second-most powerful leader in the ruling Communist Party after President Hu Jintao, witnessed the signing of the MOU.

Wu is expected to meet with US congressional leaders and officials in President Barack Obama's administration in Washington on a variety of energy, trade and business initiatives.

Wu and other Chinese officials discussed with First Solar executives the "significant potential" for the two nations to address global climate change through markets that took advantage of their solar resources, the US company said.

The MOU outlined a long-term "strategic partnership" between First Solar and Ordos City, where the US firm could consider establishing a solar panel manufacturing investment.

"Discussions with First Solar about building a factory in China demonstrate to investors in China that they can confidently invest in the most advanced technologies available," said Cao Zhichen, vice mayor of Ordos municipal government.

China has expressed plans to provide 10 percent of its energy from renewable resources by 2010 and 15 percent by 2020, including from wind, hydro, biomass and solar. Various state incentives are being introduced for such growth.

While current Chinese solar installations total about 90 megawatts, Beijing has boosted its previous solar capacity goal of 1.8 gigawatts by 2020 to two gigawatts by 2011, and 10-20 gigawatts by 2020, according to a statement issued in conjunction with the MOU signing.

The first phase of the Ordos solar power plant will be a 30-megawatt "demonstration" project that will see construction begin by June 1, 2010, officials said.

The second and third phases will be 100-megawatt and 870-megawatt projects, expected to be completed by the end of 2014, while the fourth phase will be a 1,000-megawatt facility tipped to be completed by end 2019.

(Agencies)

Space shuttle undocks from space station

In this image made from video provided by NASA astronaut John 'Danny' Olivas, STS-128 mission specialist, center left, shakes hands and thanks the commander of the space station Russia's Federal Space Agency cosmonaut Gennady Padalka before the hatches between the orbiting shuttle and station close Monday Sept. 7, 2009. The shuttle will undock Tuesday.(Photo/AP)

Space Shuttle Discovery Commander Rick Sturckow works in the Leonardo Multi-Purpose Logistics Module in this NASA handout photo taken September 6, 2009. (Xinhua/Reuters Photo)

Space Shuttle Discovery Commander Rick Sturckow (L), Nicole Stott, Expedition 20 flight engineer; and Tim Kopra, STS-128 mission specialist, pose for a photo on the middeck of the shuttle in this NASA handout photo taken September 6, 2009.(Xinhua/Reuters Photo)

CAPE CANAVERAL, Fla. 鈥?Space shuttle Discovery and its seven astronauts pulled away from the international space station on Tuesday and headed home, leaving tons of fresh supplies behind as well as a new face.

The shuttle is due back on Earth on Thursday.

"We're pretty fat with supplies now thanks to you," called out space station astronaut Michael Barratt. "God speed you on your way home."

Discovery undocked as the two spacecraft soared 220 miles above China. Pilot Kevin Ford guided the shuttle in a lap around the station, essentially for picture-taking. Barratt said he and his station crewmates were glued to the windows watching "that magnificent spaceship that just flew under us."

The shuttle astronauts quickly got started on an evening of surveying to check for any signs of micrometeorite damage and make sure their ship can return safely.

"The mission is far from complete for us, but we couldn't be more pleased with how it's gone," said LeRoy Cain, chairman of the mission management team.

Discovery's departure ended nearly nine days of linked flight in which more than 18,000 pounds of equipment and experiments were dropped off. Astronaut Nicole Stott took up residence aboard the space station, replacing Timothy Kopra, homeward bound after being off the planet for nearly two months.

Kopra should have stayed longer at the orbiting complex, but had his mission cut short by launch delays to his shuttle ride up. Tuesday marked his 55th day in space.

Despite his abbreviated stay, Kopra was eager to be reunited with his wife and two children, and said he was looking forward to a sip of beer.

Also returning aboard Discovery: Buzz Lightyear. The 12-inch action figure spent 15 months at the space station as part of a NASA educational program. The doll will take part in a tickertape parade at Walt Disney World early next month.

Another piece of pop culture, though, remained on board the space station: a treadmill named after Comedy Central's Stephen Colbert.

Colbert had campaigned for naming rights to a yet-to-be-launched space station room, but NASA went with Tranquility for that and the comedian had to settle for the exercise machine that flew up on Discovery. The $5 million treadmill won't be assembled until later this month.

Six astronauts stayed behind to continue their own lengthy missions. Stott, the newest station occupant, will remain on board until November.

Mission Control, meanwhile, determined that the space station will not need to move out of the way of a piece of space junk that will pass within roughly 45 miles early Wednesday. It's a fragment from a Chinese satellite that was blasted by a missile two years ago.

It won't be long before another spacecraft drops by. Japan's brand new cargo ship will be launched Thursday and hook up to the space station one week later. Then at the beginning of October, a Russian Soyuz spacecraft will arrive with a fresh station crew and a billionaire tourist, Cirque du Soleil founder Guy Laliberte.

The space station is now 84 percent complete with a mass of more than 710,000 pounds. Six shuttle flights remain to wrap up construction. Atlantis is up next in November with a load of big spare parts.

NASA hopes to finish the station and fly the shuttle for the last time by the end of 2010 or early 2011. The future of human spaceflight, however, is unclear. A White House panel of independent space experts said in a report Tuesday that NASA cannot afford to return astronauts to the moon by 2020 as envisioned.

(Agencies)

Yawning toons make an ape gape

This combo of handout pictures released by Japanese professor at the Primate Research Institute at Kyoto University, Tetsuro Matsuzawa, shows a chimpanzee yawning after being shown videos of other chimps yawning at a laboratory in Inuyama, Aichi Prefecture, in 2003. (Photo/AFP)

PARIS 鈥?Computer animations of yawning chimpanzees provoke the same irresistible grins in real chimps, according to an unusual study released Wednesday.

"Contagious yawning" is well known among humans, and earlier studies have shown that chimps are not immune to its suggestive influence either.

But the new research is the first to show that images seen on a monitor can provoke teeth-baring yawns in non-human primates too.

Matthew Campbell and colleagues of the Yerkes National Primate Research Center in Lawrenceville, Georgia divided 24 chimps ranging in age from nine to 43 years old into pairs.

Each pair was exposed to animated chimps in two short 3-D videos on a 48-centimetre (19-inch) screen. Only one of the videos showed the animals yawning.

The chimps may doing something deeper than simple imitation, for they may have an emotional tie with the cartoon character, the researchers believe.

"Contagious yawning is controlled by the same mechanism that makes emotions contagious," the study notes. "Our results strongly suggest an empathetic response to the animations."

The technique could provide an important tool for exploring animal behaviour and cognition, the study adds.

The study is published in a British scientific journal, Proceedings of the Royal Society B.

(Agencies)

World's first floating wind turbine opens in Norway

The world's first floating full-scale offshore wind turbine in the North Sea off the coast of Norway. Norwegian energy giant StatoilHydro said that the world's first floating full-scale offshore wind turbine has been inaugurated in the North Sea off the coast of Norway.(Photo/AFP)

OSLO 鈥?The world's first floating full-scale offshore wind turbine has been inaugurated in the North Sea off the coast of Norway, Norwegian energy giant StatoilHydro said Tuesday.

The turbine known as Hywind, which measures 65 metres (213 feet) tall and weighs 5,300 tonnes, lies some 10 kilometres (seven miles) off the island of Karmoey near the Scandinavian country's southwestern coastline, the company said.

It rests upon a floating stand that is anchored to the seabed by three cables. Water and rocks are placed inside the stand to provide balast.

StatoilHydro plans to test Hywind over the next two years before it looks to set up any more floating wind turbines with international partners.

StatoilHydro sees Japan, South Korea, California, the east coast of the United States and Spain as some of the potential markets to where this technology could be exported.

Hywind can be used in waters from 120 metres to 700 metres deep allowing it to be placed much further away from the shore than static wind turbines already in operation.

StatoilHydro's Anne Stroemmen Lycke told AFP that the floating turbine has "great advantages."

"It is not so easily seen from the coast, it can be placed in areas not used by others," she said.

"We could use such wind turbines in countries where coastal waters are very deep or where there is little space left for land-based turbines," Stroemmen Lycke added.

A total of 400 million kroner (46 million euros, 66 million dollars) has been invested in the 2.3-megawatt floating turbine, making it a far more expensive option than its fixed counterpart.

"Our goal is to bring down the price to the level of fixed wind turbines that are currently installed in waters some 60 metres deep," Stroemmen Lycke said.

France's Technip and Germany's Siemens both worked with the Norwegian energy giant on the Hywind project.

It is set to start producing electricity in the next few weeks, StatoilHydro said.

(Agencies)

Romania to launch its first space rocket in October

BUCHAREST, Sept. 9 (Xinhua) -- The Romanian Aeronautics and Cosmonautics Association (ARCA) announced on Wednesday that it will launch in October the country's first space rocket, in what is the final rehearsal for a 30 million dollar astronautic contest for landing a privately built spacecraft on the moon, initiated by the Google corporation.

The rocket dubbed Helen will be launched from a Black Sea platform and is a three-stage space rocket capable of reaching the outer space in suborbital flight, ARCA president Dumitru Popescu told a press conference.

During the Google Lunar X Prize Contest, it will reach the moon in three days, and during the Black Sea drill it is expected to reach cosmic space in two hours.

Navy watercraft will take to Black Sea high waters the launch set consisting of rocket Helen and the balloon that is to carry it to the upper atmosphere. The equipment will be unloaded from the ships onto the sea platform, where the balloon will be inflated and the rocket stages fueled with an ecological mix of hydrogen peroxide in a 70 percent concentration. The entire set has a launch weight of over 2,000 kilograms.

The rocket will be transported to the stratosphere at a 14,000-meter altitude by the world's largest solar balloon, made at ARCA.

Popescu explained that once the stratosphere is reached, the ignition of the first stage engine will be initiated and will be accelerated to a supersonic speed. When the fuel of the first stage runs out, the board computer will order the initiation of the second stage, followed by stage three. This third module actually propels the payload, consisting of the European Lunar Lander (ELL) pressurized capsule.

The capsule transports radio and satellite monitoring and telemetry equipment and cameras. It will be taken to the outer space by the third stage, followed by the procedure to re-enter the Earth atmosphere and the splash-down into the Black Sea by parachute deployment.

Meanwhile, the carrier balloon will start the descent procedure. All system elements will be tracked by radio telemetry and telecommunication satellites.

The designers of this experiment do not yet know the exact date for the rocket launch, which largely depends on weather conditions.

ARCA is a non-governmental organization, national leader in aero-spatial research, and a major competitor, starting 2002, in the most prestigious space competition awarded with the Ansari X Prize.

Founded in 2007, the Google Lunar X Prize competition is aimed at kicking off a rocket to the moon capable to successfully land a mobile spacecraft on the Earth's satellite, move it across 500 meters and beam home high-definition television views from the lunar surface.

U.S., Canada sign agreement on civil space co-op

WASHINGTON, Sept. 9 (Xinhua) -- NASA Administrator Charles Bolden and Canadian Space Agency President Steve MacLean signed a framework agreement Wednesday for cooperative activities in the exploration and use of outer space for peaceful purposes, NASA said.

The framework agreement is an important step in an evolving process toward a coordinated and comprehensive approach to exploration and use of outer space. It sets forth general terms and conditions that will be applied to future cooperative projects and facilitates expanded cooperation between the U.S. and Canada on a range of activities related to human spaceflight, exploration, space science and Earth science.

"NASA is very proud of its long and outstanding relationship with Canada, one that has been nurtured during the past four decades with increasing collaboration in a wide range of space science and exploration activities," NASA's Bolden said.

"As NASA continues to enhance the scientific observation of our planet and the solar system, we are looking to Canada and our other international partners to play key roles in our future exploration plans."

Commenting on the significance of the signing at Canadian Embassy in Washington D.C., MacLean said, "The United States has been a critical partner for Canada ever since the launch of the Alouette-1 satellite in 1962. From these early beginnings, we have worked together to forge a space alliance that has become a catalyst, driving generations of space expertise, innovation, science, and technological excellence through our participation in space projects that continue to serve the interests of both our nations."

Walruses congregate on Alaska shore as ice melts

In this undated photo provided by the U.S. Fish and Wildlife Service, walrus swim to shore on a beach in Alaska. Thousands of walrus are congregating on Alaska's northwest coast because of receding sea ice in the Arctic. (Photo/AP)

In this undated photo provided by the U.S. Fish and Wildlife Service, walrus congregate on a beach in Alaska. (Photo/AP)

ANCHORAGE, Alaska 鈥?Thousands of walruses are congregating on Alaska's northwest coast, a sign that their Arctic sea ice environment has been altered by climate change.

Chad Jay, a U.S. Geological Survey walrus researcher, said Wednesday that about 3,500 walruses were near Icy Cape on the Chukchi Sea, some 140 miles southwest of Barrow.

Animals the agency tagged with satellite transmitters also were detected on shore at Cape Lisburne about 150 miles farther down the coast.

Walruses for years came ashore intermittently during their fall southward migration but not so early and not in such numbers.

"This is actually all new," Jay said. "They did this in 2007, and it's a result of the sea ice retreating off the continental shelf."

Federal managers and researchers say walruses hauling out on shore could lead to deadly stampedes and too much pressure on prey within swimming range. Projections of continued sea ice loss means the phenomenon likely is not going away.

"It's more of the same," Jay said. "What we've been seeing over the past few years with reduced sea ice conditions, we might be seeing this more and more often, and it's probably not good for the walruses," he said.

Unlike many seals, walruses cannot swim indefinitely and must rest periodically between feeding forays. They rely on sea ice as a platform for foraging for clams in the shallow waters of the outer continental shelf. They can dive up to 630 feet for clams and other sea floor creatures but mostly feed in waters of less than 330 feet, Jay said. Beyond the continental shelf, water can reach depths of 10,000 feet or more.

An estimated 6,000 or more walruses congregated on Alaska's shore in the fall of 2007, taking scientists by surprise.

Herds were in the tens of thousands at some locations on the Russian side of the Chukchi Sea, with an estimated 40,000 animals at Point Shmidt. Russian biologists reported 3,000 to 4,000 walruses out of population of perhaps 200,000 died, mostly young animals crushed in stampedes.

Alaska herds did not experience that sort of mortality but scientists acknowledge a concern when the marine mammals are concentrated on a rocky shore rather than hundreds of miles of sea ice edge.

"They may have a much higher predation pressure on those nearshore areas when they're using those land haulouts than when they're using sea ice," Jay said.

The Center for Biological Diversity has petitioned to list the Pacific walrus as an endangered or threatened because of habitat loss due to warming. The U.S. Fish and Wildlife Service on Tuesday agreed to begin a detailed status review. A 60-day public comment period will precede an agency listing decision by October 2010. A final decision would be made by the Interior secretary by October 2011.

The agency is working with the Federal Aviation Administration to warn away pilots, who can cause stampedes, said walrus researcher Joel Garlich-Miller. So can polar bears or human hunters. There is no legal mechanism to keep hunters away, he said, but people have been letting the animals rest.

USGS researchers plan to head to the Chukchi coast next week to place satellite tags on up to 30 animals so their foraging habits can be studied, Jay said.

The 2007 herds prompted researchers to gear up for studies of the animals' new habits last year. However, remnant ice floating apart from the main pack ice kept walruses off shore, Jay said. Their reappearance put the research plans into motion.

"We're trying to get more information on how the walruses are responding to the loss of sea ice over the continental shelf, where do they go when they do come to shore like this, how far offshore are they foraging," he said.

On land, walruses have to swim out and return rather than diving vertically. That could lead to nutritional stress.

"We suspect that it's going to cost them more energy to do that than if they were able to stay on the sea ice," he said.

Jay has not heard reports of walrus congregating on Russian shores. One animal tagged on the U.S. side has hauled out there and herds likely are gathering, he said.

(Agencies)

Newly fixed Hubble's deep space photos again amaze

This undated handout image provided by NASA, released Wednesday, Sept. 9, 2009, taken by the refurbished Hubble Space Telescope, shows a clash among members of a famous galaxy quintet revealing an assortment of stars across a wide color range, from young, blue stars to aging, red stars.(Photo/AP)

This undated handout image provided by NASA, released Wednesday, Sept. 9, 2009, taken by the refurbished Hubble Space Telescope, shows stars bursting to life in the chaotic Carina Nebula.(Photo/AP)

This undated handout image provided by NASA, released Wednesday, Sept. 9, 2009, taken by the refurbished Hubble Space Telescope, shows a celestial object that looks like a delicate butterfly.(Photo/AP)

This undated handout image provided by NASA, released Wednesday, Sept. 9, 2009, taken by the refurbished Hubble Space Telescope, shows Barred Spiral Galaxy NGC 6217.(Photo/AP)

WASHINGTON 鈥?A refurbished Hubble Space Telescope is showing Earth the sharpest photos yet of cosmic beauty, complete with heavenly glows. NASA on Wednesday unveiled the first deep space photos taken by Hubble since its billion dollar repair mission last spring. That work included installing two new cameras, other science instruments and replacing broken parts.

"Hubble is back in action. Together, NASA and Hubble are opening new vistas on the universe," astronomer and frequent Hubble user Heidi Hammel said.

The 10 images of galaxies and nebulas 鈥?clouds of stellar gas and dust 鈥?are sharper than previous photos taken of the same places by Hubble before its fifth and final upgrade. Some have brilliant glows of light that give them halos that to some people can appear heavenly. And one of those resembles an eerie cosmic butterfly, but is really a stellar nursery or nebula not too far away

The butterfly photo shows details, such as gassy folds in what looks like butterfly wings, that the Hubble previously could not see, said Hubble senior scientist Dave Leckrone.

The glow in that photo and others is hot gas and dust pushed out from the stars, Leckrone said. In a way, it's like a lightbulb, with the star as the filament but the overall glow from the gas, he said.

The images, especially the butterfly, don't just show science, but can evoke a sense of spirituality, Leckrone said.

"What I see is the grandeur of creation, however it got there," Leckrone told The Associated Press.

The most stunning photos involve the cosmos at its most violent: the birth and death of stars.

One shows the stellar nursery Carina Nebula, about 7,500 light years away. A light year is nearly 6 trillion miles. The photo shows an eerie backlit reddish cloud being bombarded by radiation. When Hubble's new camera uses a different light spectrum, the cloud disappears and the infant stars appear. They are only about 100,000 years old with white jets shooting out.

Those jets are cosmic debris "being blasted out at very high velocity at what's going to be a planetary system," said University of Virginia astronomer Bob O'Connell.

Another image shows a compact cluster of thousands of stars 鈥?a field of white glimmering with dots of blazing hot blue stars and cooler red ones.

All but one of the Hubble photos are from inside the Milky Way galaxy. The exception caught five spiral galaxies in a single image.

Soon Hubble will turn its new cameras to the furthest edges of the universe and take photos from soon after the Big Bang.

"Our view of the universe and our place within it will never be the same," NASA Administrator Charles Bolden, who as an astronaut piloted the space shuttle that put Hubble in orbit 19 years ago.

Since the repairs, Leckrone said there has not been a single technical problem with Hubble, which was plagued by blurry images when it was first launched. The first photos from the repaired Hubble came earlier this summer, when the telescope took pictures of Jupiter when an asteroid or comet hit it. They were unscheduled quick black-and-white looks; the photos released Wednesday were planned, longer observations.

The astronauts who helped repair Hubble basked in the celebration of the new photos.

"The hair was standing up on the back of my neck to see the potential of this telescope," said John Grunsfeld.

Mike Massimino said his reaction on seeing the photos was: "Thank God, we didn't break it."

(Agencies)

Space shuttle and crew aim for Thursday landing

CAPE CANAVERAL, Fla. 鈥?Shuttle Discovery's astronauts aimed for a Thursday evening landing to wrap up their successful space station delivery mission, but late summer storms threatened to keep them up an extra day or two.

Mission Control said Wednesday that "the weather will pose a challenge" for bringing Discovery home. The forecast called for a chance of thunderstorms. Conditions were expected to worsen Friday and remain poor Saturday.

"The weather in Florida this time of year is always a little iffy," Discovery's commander, Rick Sturckow, said from orbit. "If things aren't good, the worst that can come out of it is that we have another day in space, which is a great deal."

In orbit since Aug. 29, Discovery has enough supplies to last until Sunday. If the shuttle cannot return to Florida on Thursday, NASA will consider landing it in California, but not until Friday at the earliest.

Astronaut Timothy Kopra is headed home after nearly two months at the international space station. He said the flight wasn't too long by any stretch. He should have spent an extra month at the outpost, but his ride up ended up being delayed because of shuttle problems.

Buzz Lightyear, by comparison, spent 15 months aboard the space station.

The 12-inch action figure rocketed into "infinity and beyond" aboard Discovery in May 2008. Once Walt Disney World gets the toy back, it will be feted at a tickertape parade early next month with Buzz Aldrin, the second man to walk on the moon.

Kopra assured a TV interviewer that Buzz is doing well after so long in space.

"He's very secure. He's in his spacesuit, and I'm quite confident that he'll have a very safe ride home. But we obviously cannot disclose his location upon the space shuttle," Kopra joked. He kept a serious face, but his crewmates chuckled.

Sturckow and his crew spent Wednesday checking their flight systems to make sure everything was in order for re-entry. While that was happening, a small object resembling a strip of cloth floated away from the left side of the shuttle, back along the payload bay.

Mission Control assured the astronauts that while no one could identify the piece, it was not part of the shuttle's thermal shielding and posed no safety concern for re-entry.

Columbia was destroyed during re-entry in 2003 because of a gashed wing. It wasn't until later that a space surveillance review discovered an object floating away from Columbia on flight day two; experts believe it was part of a wing panel.

NASA cleared Discovery for re-entry after reviewing all the laser images sent down by the astronauts Tuesday from a survey of the vulnerable wings and nose. No micrometeorite damage was found.

Thanks to restocking by Discovery, the space station now has enough food to last until February, as well as a spare air-cleanser and new treadmill. The exercise machine is named Colbert in honor of the TV comedian. More supplies will arrive on a Japanese vessel that's due to lift off Thursday, just before Discovery's scheduled 7:05 p.m. touchdown.

(Agencies)

Newly found stem cell causes prostate cancer

PARIS 鈥?Scientists in the United States, working with mice, have found a new type of stem cell in the prostate gland and shown that mutations in it can cause cancer, a study released Wednesday says.

The discovery boosts evidence that cancers can be caused by modifications in stem cells, the dynamic precursor cells that develop into and replenish the body's specific tissues, it says.

It also appears to resolve a mystery about the origin of prostate cancer, and could open new pathways for treatment of the deadly disease.

"This is a new stem cell in the prostate, and our research shows that it can serve as a cell of origin for prostate cancer," said Cory Abate-Shen, a professor at the Columbia University College of Physicians and Surgeons and New York and a co-author of the study.

Prostate cancer is the second most common cancer among men, claiming half a million lives each year worldwide, according to the World Health Organisation (WHO).

The new stem cell, known by the acronym of CARN, is found inside a type of tissue called the epithelium, which is also present in other parts of the body.

More specifically, they are located in a region called the luminal layer, where cancers of the prostate are known to occur.

But until now, the only stem cell found in the epithelium were in the so-called basal layer.

Hence the conundrum: if stem cells were implicated in the growth of cancerous tumours, as growing evidence suggests, how the cancer moved from one layer to the next remained unexplained.

To see if mutant versions of the newly-found cell can cause tumours, scientists deleted a cancer suppressor gene called Pten in laboratory mice.

"Pten is a very critical gene for cancer. It is a major tumour suppressor and is especially important for prostate cancer" in humans, Abate-Shen told AFP.

Male mice with the mutant version of the luminal stem cells all developed tumours, but "control" mice whose Pten gene had not been suppressed were all healthy.

The study, led by Abate-Shen's husband, Michael Shen, of Columbia Medical Center, is published in the British-based journal Nature.

The findings should help scientists better understand the link between stem and cancer cells, the authors said.

"Alterations in most cells in a tissue may not be a problem for carcinogenesis," or the rise of cancer, said Abate-Shen.

"But if those alterations occur in stem cells, then they give rise to tumours because those are the cells that proliferate and give rise to the rest of the cells."

The researchers cautioned against drawing hasty conclusions for humans on the basis of mouse models. It is unclear whether CARNs exist in the human prostate and if, so, whether they unleash cancer.

The next step is to compare normal and cancerous cases in mice, and then relate those findings to human cancer, said Abate-Shen.

The main function of the prostate gland is the secretion of a slightly alkaline fluid that helps semen neutralise the acidity of the vaginal tract, prolonging the lifespan of sperm as they seek an egg to fertilise.

(Agencies)

Canadian billionaire takes exam at Star City space centre

Canadian billionaire Guy Laliberte prepares for the exam, as part of the final stage of his training course, at the Star City space centre outside Moscow, September 9, 2009. The Canadian billionaire, who owns Cirque du Soleil, is set to become the world's seventh, and Canada's first space tourist slated to travel on a Russian Soyuz space craft to the International Space Station at the end of September. (AFP Photo)

Canadian billionaire Guy Laliberte poses for a picture before taking the exam, as part of the final stage of his training course, at the Star City space centre outside Moscow, September 9, 2009. Laliberte, who owns Cirque du Soleil, is on the countdown to become the world's seventh, and Canada's first space tourist slated to travel on a Russian Soyuz space craft to the International Space Station at the end of September. (Reuters Photo)

Canadian billionaire Guy Laliberte prepares for the exam, as part of the final stage of his training course, at the Star City space centre outside Moscow, September 9, 2009. The Canadian billionaire, who owns Cirque du Soleil, is set to become the world's seventh, and Canada's first space tourist slated to travel on a Russian Soyuz space craft to the International Space Station at the end of September.(Reuters Photo)

U.S. astronaut Jeffrey Williams (R), Canadian billionaire Guy Laliberte (L) and Russian cosmonaut Maxim Surayev pose for a picture in front of a landing capsule before taking an exam, as part of the final stage of their training course, at the Star City space centre outside Moscow, September 9, 2009.(Reuters Photo)

Canadian billionaire Guy Laliberte prepares for the exam, as part of the final stage of his training course, at the Star City space centre outside Moscow, September 9, 2009.