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)