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Author Topic: Recent Science News Stories and Science Articles  (Read 202380 times)


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" Prison calls on dog to sniff out illicit phones

Give the dog a phone: a sniffer dog has been put to work in British prisons with the specific brief of tracking down illicit mobile phones held by inmates.

Murphy, a 15-month-old English springer spaniel, has started work at Norwich Prison in eastern England and will be working at 12 other jails in the region.

Norwich Prison governor James Shanley says their biggest concern is to maintain public protection.

"And we do not want mobile phones to circumvent all the systems set up to provide this," he said.

"If somebody has access to a mobile phone in prison they could potentially contact witnesses, or they could use the phone as a means of escape by arranging for someone to meet them at a certain place.

"Phones can also be used to take photos and could identify staff or other visitors to the prison."

Mr Shanley says about 500 mobile phones have been found in the 12 prisons in the past year.

Murphy, who came from a rescue centre, is believed to be the first mobile phone sniffer dog in Britain's Prison Service. "



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" Cloning without stem cells works  

US scientists say stem cells are not necessary for cloning and other cells may even be better candidates.

The Pittsburgh University team created two baby mice from a fully matured blood cell that itself is incapable of making more of its own kind.

It had been thought only immature stem cells, which can become many types of other cell, were capable of doing this.

A UK expert said the Nature Genetics study disproved the idea that only immature cells were of use for cloning.

Alternative routes

Somatic cell nuclear transfer (SCNT) - the scientific term for cloning - is creating an embryo by taking the nucleus, which houses the genetic material of a cell, from one cell and putting it into an unfertilised egg that has had its own genetic material removed.

The resulting embryo is then an exact genetic copy of the cell from the animal or person that donated the nucleus.

Embryonic stem cells - derived from embryos that develop from eggs that have been fertilized
Adult stem cells - immature cells that have yet to fully develop, and found in tissue and organs

Stem cells are still at an early stage of development, and retain the potential to turn into many different types of cell that make up tissues and organs, which is why experts have heralded their promise for treating a variety of genetic diseases.

But experiments using adult stem cells taken from mature tissue to make early stage embryos have yielded disappointing results, with success rates of 1-5%.

Dr Tao Cheng and colleagues tested whether a fully matured type of white blood cell, called a granulocyte, could propagate early embryos.

Not only was this successful, the granulocyte was far better at this than its immature ancestor cells destined to become granulocytes. "
« Last Edit: 03/10/2006 16:18:04 by ROBERT »


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" Spider Silk Could Repair Human Ligaments
By Charles Q. Choi
Special to LiveScience
posted: 13 October 2006
10:29 am ET  

Spider web silk, the strongest natural fiber known, could possess untapped medical potential in artificial tendons or for regenerating ligaments, scientists now say.

A body of folklore dating back at least 2,000 years tells of the potential medical value of spider webs in fighting infections, stemming bleeding and healing wounds, explained molecular biologist Randolph Lewis at the University of Wyoming in Laramie. Spider webs have even found a place in Shakespeare's play "A Midsummer Night's Dream," where the character dubbed Bottom noted, "Good Master Cobweb: if I cut my finger, I shall make bold with you."

While research has found no evidence so far that spider webs can kill germs, Lewis explained, studies on animals have revealed that spider silk triggers little if any immune responses, which cause rejection of medical implants.

So his lab and others are spinning spider silks into fibers that they hope might be useful in medicine.

Lewis said researchers at Tufts University in Medford, Mass., have found that spider webs could be used as scaffolds for regenerating ligaments damaged in one of the world's most common knee injuries—ruptured anterior cruciate ligaments, or ACLs. "We're also looking at spider silk in artificial tendons," he said.

Scientists are also developing spider silk to make exceptionally fine sutures for stitching up surgeries or wounds to nerves or eyes, to potentially help them heal without scarring.

"Right now we haven't even optimized the silks we've produced yet, and we're in the ballpark of the material properties you'd want for artificial tendons and ligaments," Lewis told LiveScience.

To mass-produce spider silk, Lewis said "our lab is pursuing the production of spider silk in alfalfa." Other researchers are experimenting with producing spider silk proteins in goat milk. Scientists generate these proteins outside spiders by inserting the genes for them into target cells.

Lewis summed up current work in the latest issue of the journal Chemical Reviews. "


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" Doubt cast on lunar ice deposits  

By Paul Rincon
Science Reporter, BBC News, Wednesday, 18 October 2006.
Nasa hopes to return humans to the Moon by 2020
Hopes that the Moon's south pole has significant water ice deposits that could be used to set up a lunar base appear to be unfounded, a study says.

Hypothesised deposits of lunar water-ice have figured in Nasa's planning for future Moon landings.

This resource would be invaluable for supplying bases and making fuel for propelling spacecraft beyond the Moon.

The study in Nature journal suggests radar echoes thought to be from frozen water could be from rocky debris.

The simplest explanation is that we're looking at a signature due to [impact debris] from the crater and not some strange signature due to water ice

Jean-Luc Margot, Cornell University
The first evidence for water-ice deposits came from radar observations made by the US Moon orbiter Clementine, launched in 1994.

According to mission scientists, values for a radar signature called the "circular polarisation ratio (CPR)" indicated frozen water below the dust in craters near the lunar south pole that were shaded from the Sun.

The Clementine researchers also admitted that this radar signature could be created by echoes from rough terrain and walls of impact craters.

In the latest study, Donald Campbell of Cornell University in Ithaca, New York, and colleagues suggest the latter explanation is the more likely. "


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" Stem cell insulin offers hope to type 1 diabetics

28 October 2006

INSULIN-secreting cells have been created from human embryonic stem cells for the first time, raising hopes of a limitless supply of cells that could be transplanted into people with type 1 diabetes.

Emmanuel Baetge and his colleagues at Novocell in San Diego, California, used a cocktail of chemicals to coax the stem cells to form pancreatic cells (Nature Biotechnology, DOI: 10.1038/nbt1259). The cells produce as much insulin as normal pancreatic islet cells, but unlike adult islet cells, this doesn't appear to be regulated by sugar levels. Baetge is confident they can overcome this problem.

If they succeed, the company has also developed a way to coat the cells in a polymer called polyethylene glycol, which would prevent them from being rejected by the recipient's immune system, while allowing sugar, insulin and other signalling molecules to filter in and out. "



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Dolphin May Have 'Remains' of Legs

Possible Evidence Ocean Mammals Lived on Land
In this photo released by Taiji Whale Museum, divers hold a bottlenose dolphin which has an extra set of human palm-sized fins near its tail in Taiji, Wakayama prefecture (state) in western Japan, on Saturday November 4, 2006. Japanese researchers said Sunday that the could be the remains of back legs, providing further evidence that ocean-dwelling mammals once lived on land. (AP Photo/Taiji Whale Museum)


TOKYO Nov 6, 2006 (AP)— Japanese researchers said Sunday that a bottlenose dolphin captured last month has an extra set of fins that could be the remains of hind legs, a discovery that may provide further evidence that ocean-dwelling mammals once lived on land.

Fishermen captured the four-finned dolphin alive off the coast of Wakayama prefecture (state) in western Japan on Oct. 28, and alerted the nearby Taiji Whaling Museum, according to museum director Katsuki Hayashi.

Fossil remains show dolphins and whales were four-footed land animals about 50 million years ago and share the same common ancestor as hippos and deer. Scientists believe they later transitioned to an aquatic lifestyle and their hind limbs disappeared.

Whale and dolphin fetuses also show signs of hind protrusions but these generally disappear before birth.

Though odd-shaped protrusions have been found near the tails of dolphins and whales captured in the past, researchers say this was the first time one had been found with well-developed, symmetrical fins, Hayashi said.

"I believe the fins may be remains from the time when dolphins' ancient ancestors lived on land … this is an unprecedented discovery," Seiji Osumi, an adviser at Tokyo's Institute of Cetacean Research, said at a news conference televised Sunday.

The second set of fins much smaller than the dolphin's front fins are about the size of human hands and protrude from near the tail on the dolphin's underside. The dolphin measures 8.92 feet and is about five years old, according to the museum.

Hayashi said he could not tell from watching the dolphin swim in a musuem tank whether it used its back fins to maneuver.

A freak mutation may have caused the ancient trait to reassert itself, Osumi said. The dolphin will be kept at the Taiji museum to undergo X-ray and DNA tests, according to Hayashi.

"Dolphin with extra fins" sounds like a dish on a Japanese menu  :)
« Last Edit: 13/11/2006 16:45:35 by ROBERT »

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'Nymph of the sea' reveals remarkable brood

The scientists discovered the mother complete with her brood of some 20 eggs and 2 possible juveniles inside, together with other details of her soft part anatomy including legs and eyes.

The research team consisted of David Siveter from the University of Leicester, Derek Siveter from Oxford, Mark Sutton from Imperial College London and Derek Briggs from Yale.

The team has made a digital image of the fossil - an ostracod (a relative of the shrimps) - which is preserved exceptionally in volcanic ash rocks in Herefordshire. Their findings are published on line in the Proceedings of the Royal Society.

Professor David Siveter, of the Department of Geology at the University of Leicester, said : "Ostracods are common, pin-head sized crustaceans known from thousands of living species in garden ponds to oceans and from countless fossil shells up to 500 million years old; however, their fossilized soft-parts are exceedingly rare.

"Supposed examples of fossil invertebrate eggs are also few. The fossil we have found contains soft-part anatomy such as legs and eyes and also includes about twenty eggs, each about half a millimetre in size, and two possible juveniles.

"The fossil has been christened Nymphatelina gravida, meaning' a pregnant young woman of the sea'. This remarkable discovery provides an unequivocal and unique view of parental brood care in the invertebrate fossil record, it allows gender to be determined in an animal as old as the Silurian period of geological time, and indicates a remarkably conserved egg brooding reproductive strategy."


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Dad inspired 'Jurassic Park,' son inspires 'Jurassic Poop'
Book reveals how ancient poop has the inside scoop on US past

November 15th, 2006 -- Twenty-five years ago American entomologist George Poinar's work on ancient insects in amber inspired Michael Crichton's futuristic thriller Jurassic Park. Now son Hendrik Poinar's groundbreaking work has inspired the world's first book on the science of fossil feces, Jurassic Poop.

The new children's book by Canadian science writer Jacob Berkowitz reveals that America not only has the world's largest heap of ancient human leavings but that the study of coprolites, or fossil feces, is literally re-writing American history, including who attended the first Thanksgiving.

Developed completely from original scientific sources, Jurassic Poop is the first comprehensive book on coprolites, full of facts and stories that are intriguing to readers five to 100.

"When I saw my first coprolite ten years ago, I thought no way, how could something as soft as poop fossilize?," says Berkowitz. "But coprolites are found on every continent and from every geological time period. There's literally tons of fossil poop out there, and it's now recognized as priceless for helping scientists piece together the puzzle of ancient life."

Jurassic Poop profiles the work of Hendrik Poinar, a professor at McMaster University, in Hamilton, Canada. He was the first ever to extract DNA from ancient feces.

While his father's work in teasing DNA from insects in amber benefited from the revolutionary genetic technological advances of the 1980s -- particularly the invention of the polymerase chain reaction (PCR) to duplicate and thereby identify DNA fragments -- Hendrik's benefited from medical advances. The technique used to extract DNA from coprolites uses a chemical developed for the treatment of diabetes-related complications.

"After being pooh-poohed by scientists for decades, coprolites have now been shown to be the best source of ancient DNA, better than bones and teeth," says Berkowitz. Hendrik Poinar is now able to identify not only a pooper's gender, but also critical genetic information that will help to uncover the very origins of modern humans.

Berkowitz says coprolites even have something to say about one of the seminal stories in American history, the arrival of the Mayflower.

The official Mayflower record says that the only animals on board were two dogs. But in the mid-1990s an archaeological excavation of a 17th century Boston privy revealed another story. The Mayflower was infested with at least 20 types of Old World beetles, stow-aways who quickly called America home -- and do to this day.

Jurassic Poop also reveals that more than 1000 human coprolites have been collected from Hinds Cave in the Chihuahuan desert in southwest Texas, making the site the largest human coprolite cache ever found.

The fossilized specimens were deposited by ancient Americans over the course of about 8000 years. The book notes that these human remains are about 95-per cent fibre. That's about 15 times the amount of fibre the average American eats today. Hendrik Poinar is now collaborating with Vaughn Bryant of Texas A&M University to extract genetic information from the Hinds Cave coprolites.


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Volcanic blast likely killed and preserved juvenile fossil plesiosaur found in Antarctica
Skeleton to be unveiled at US museum December 13

Amid 70-mile-an-hour winds and freezing Antarctic conditions, an American-Argentine research team has recovered the well-preserved fossil skeleton of a juvenile plesiosaur--a marine reptile that swam the waters of the Southern Ocean roughly 70 million years ago.

The fossil remains represent one of the most-complete plesiosaur skeletons ever found and is thought to be the best-articulated fossil skeleton ever recovered from Antarctica. The creature would have inhabited Antarctic waters during a period when the Earth and oceans were far warmer than they are today.

James E. Martin, curator of vertebrate paleontology and coordinator of the paleontology program at the South Dakota School of Mines and Technology's Museum of Geology, announced today the plesiosaur bones will be unveiled at the museum on Dec.13, 2006.

The long-necked, diamond-finned plesiosaurs are probably most familiar as the legendary inhabitants of Scotland's Loch Ness, although scientific evidence indicates the marine carnivores have been extinct for millions of years. But when the creatures were alive, their paddle-like fins would have allowed them to "fly through the water" in a motion very similar to modern-day penguins.

Martin, an expert on fossil marine reptiles, co-led the 2005 expedition to Antarctica that recovered the plesiosaur. Judd Case, of Eastern Washington University, and Marcelo Reguero of the Museo de La Plata, Argentina, were also co- leaders.

The National Science Foundation (NSF) and the Instituto Antártico Argentino, directed by Sergio Marenssi, funded the expedition. The Argentine Air Force provided helicopter support.

NSF manages the U.S Antarctic Program, which coordinates all U.S. research on the southernmost continent. The White House has designated NSF as the lead federal agency for the International Polar Year, a 2-year global research campaign in the polar regions that begins in March 2007.

Preserved by a volcanic blast

After it was prepared in the United States, Martin said, the specimen was discovered tobe the 5-foot-long (1.5 meters) skeleton of a long-necked (elasmosaurid) plesiosaur. An adult specimen could reach over 32 feet (10 meters) in length. Most of the bones of the baby plesiosaur had not developed distinct ends due to the youth of the specimen, he said.

But the animal's stomach area was spectacularly preserved. Stomach ribs (gastralia) span the abdomen, and rather than being long, straight bones like those of most plesiosaurs, these are forked, sometimes into three prongs. Moreover, numerous small, rounded stomach stones (gastroliths) are concentrated within the abdominal cavity, indicating stomach stones were ingested even by juvenile plesiosaurs to help maintain buoyancy or to aid digestion.

The skeleton is nearly perfectly articulated as it would have been in life, but the skull has eroded away from the body. Extreme weather at the excavation site on Vega Island off the Antarctic Peninsula and lack of field time prevented further exploration for the eroded skull.

The researchers speculate volcanism similar to the massive eruption of Mt. St. Helens in Washington in 1980, may have caused the animal's death. Excavation turned up volcanic ash beds layered within the shallow marine sands at the site, and chunks of ash were found with plant material inside. That suggests a major blow-down of trees as was observed when Mt. St. Helens erupted. Either the blast or ash dumped into the ocean, the scientists say, may have caused the baby's demise. Moreover, silica released from the ash allowed spectacular preservation of the skeleton.

High winds, freezing water, hard work

As with the find of a new species of dinosaur Martin and Case made in Antarctica several years ago, the weather and the harsh Antarctic climate made collecting the plesiosaur specimen exceedingly difficult. Weeks of winds exceeding 70 miles an hour hindered the excavation. At the end of the work, icy temperatures turned water to slush before plaster could be mixed to encase the fossil for transportation. The ground was so frozen a digging tool snapped in half during the excavation. Finally, a jackhammer had to be carried up to the site in backpacks along with gasoline, plaster, and water.

The resulting package of plesiosaur remains encased in a protective plaster jacket was too large to carry, so the Argentine air force brought helicopters to the rescue. It took five men to lift the specimen into the chopper, which delivered the cargo to the tent camp on the shores of Herbert Sound. The specimen was later picked up by the Laurence M. Gould, an NSF-chartered research vessel.

At the Museum of Geology, the reptile was prepared by Michelle Pinsdorf and replicated by Shawna Johnson, both master's degree students of paleontology at the South Dakota School of Mines.

A prehistoric nursery

J. Foster Sawyer, of the South Dakota Geological Survey and the School of Mines, found the skeleton while working with Martin at an elevation of 650 feet (200 meters) on Vega Island. Sawyer found vertebrae exposed by wind from the ancient sandy seabed. The bones were embedded in rocks and associated with marine shellfish that suggest the area was a shallow-water marine environment roughly 70 million years ago. Two other partial plesiosaurs were also collected, as well as finds of very advanced shore birds.

Since 1998, expeditions by the American-Argentine team to the area--in part to compare the ancient climates of South Dakota and Antarctica--have secured numerous isolated elements of juvenile plesiosaurs and mosasaurs, a giant marine reptile that looked like an alligator with fins. Martin and his colleagues believe the site may have been a shallow-water area where marine reptiles had their young, and where the young remained until they were of sufficient size and ability to survive in open waters.

Whether plesiosaurs gave live birth has not been proved, but numerous bones and partial skeletons of larger plesiosaurs were found in the same area as the young. Given the long history of plesiosaurs, evolution would have had ample time for them to develop a form of live birth.

The juvenile plesiosaur appears to be related to one discovered in New Zealand in 1874. That plesiosaur was named Mauisaurus and is characterized by a rounded end of the major paddle bone. It was confined to the southern oceans where it existed more than 5 million years.



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Supercomputer studies Milky Way's halo of dark matter

Researchers at the University of California, Santa Cruz, have used NASA's most powerful supercomputer to run the largest simulation to date of the formation and evolution of the dark matter halo that envelopes the Milky Way galaxy. Their results show substructures within the halo in unprecedented detail, providing a valuable tool for understanding the evolutionary history of our galaxy.

Every galaxy is surrounded by a halo of mysterious dark matter that can only be detected indirectly by observing its gravitational effects. The invisible halo is much larger and more spherical than the luminous galaxy at its center. Recent computer simulations have shown that the halo is surprisingly clumpy, with relatively dense concentrations of dark matter in gravitationally bound 'subhalos' within the halo. The new study, which has been accepted for publication in the Astrophysical Journal, shows much more extensive substructure than any previous study.

"We find almost 10,000 subhalos, about one order of magnitude more than in any past simulations, and some of our subhalos exhibit 'subsubstructure.' This was expected theoretically, but we have shown it for the first time in a numerical simulation," said Piero Madau, professor of astronomy and astrophysics at UCSC and a coauthor of the paper.

Jurg Diemand, a Hubble postdoctoral fellow at UCSC and first author of the paper, said the new results exacerbate what is known as the "missing satellite problem." The problem is that the clumpiness of the normal matter in and around our galaxy--in the form of dwarf satellite galaxies--does not match the clumpiness of the dark matter seen in the simulation.

"Astronomers keep discovering new dwarf galaxies, but there are still only about 15 or so, compared to about 120 dark matter subhalos of comparable size in our simulation. So which ones host the dwarf galaxies, and why?" Diemand said.

Theoretical models in which star formation is restricted to certain types of dark matter halos--sufficiently massive or early-forming ones--may help to resolve the discrepancy, Madau said.

Although the nature of dark matter remains a mystery, it appears to account for about 82 percent of the matter in the universe. As a result, the evolution of structure in the universe has been driven by the gravitational interactions of dark matter. The "normal" matter that forms gas and stars has fallen into the "gravitational wells" created by clumps of dark matter, giving rise to galaxies in the centers of dark matter halos.

Initially, gravity acted on slight density fluctuations present shortly after the Big Bang to pull together the first clumps of dark matter. These grew into larger and larger clumps through the hierarchical merging of smaller progenitors. This is the process the UCSC researchers simulated on the Columbia supercomputer at the NASA Ames Research Center, one of the fastest computers in the world. The simulation took a couple of months to complete, running on 300 to 400 processors at a time for 320,000 "cpu-hours," Diemand said.

Coauthor Michael Kuhlen, who began working on the project as a graduate student at UCSC and is now at the Institute for Advanced Study in Princeton, said the researchers set the initial conditions based on the most recent results from the Wilkinson Microwave Anisotropy Probe (WMAP) experiment. Released in March, the new WMAP results provide the most detailed picture ever of the infant universe.

The simulation starts at about 50 million years after the Big Bang and calculates the interactions of 234 million particles of dark matter over 13.7 billion years of cosmological time to produce a halo on the same scale as the Milky Way's. The clumps within the halo are the remnants of mergers in which the cores of smaller halos survived as gravitationally bound subhalos orbiting within the larger host system.

The simulation produced five massive subhalos (each more than 30 million times the mass of the Sun) and many smaller ones within the inner 10 percent of the host halo. Yet only one known dwarf galaxy (Sagittarius) is that close to the center of the Milky Way, Diemand said.

"There are big clumps of dark matter in the same region where the disk of the Milky Way would be. So even in the local neighborhood of our solar system, the distribution of dark matter may be more complicated than we have assumed," he said.

Astronomers may be able to detect clumps of dark matter within the Milky Way's halo with future gamma-ray telescopes, but only if the dark matter consists of the types of particles that would give rise to gamma-ray emissions. Certain dark matter candidates--such as the neutralino, a theoretical particle predicted by supersymmetry theory--could annihilate (that is, be mutually destroyed) in collisions, generating new particles and emitting gamma rays.

"Existing gamma-ray telescopes have not detected dark matter annihilation, but upcoming experiments will be more sensitive, so there is some hope that individual subhalos may produce an observable signature," Kuhlen said.

In particular, astronomers look forward to interesting results from the Gamma Ray Large Area Space Telescope (GLAST), scheduled for launch in 2007, he said.

The simulation also provides a useful tool for observational astronomers studying the oldest stars in our galaxy by providing a link between current observations and earlier phases of galaxy formation, Diemand said.

"The first small galaxies formed very early, about 500 million years after the Big Bang, and there are still today stars in our galaxy that formed at this early time, like a fossil record of early star formation. Our simulation can provide the context for where those old stars came from and how they ended up in dwarf galaxies and in certain orbits in the stellar halo today," Diemand said.


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Nasa and Google reach for the stars

By Chris Nuttall in San Francisco

Published: December 19 2006 01:00 | Last updated: December 19 2006 01:00

Google is extending its reach to the stars in an agreement with Nasa that will allow it to present web visualisations of the US space agency’s data on the universe.

Nasa’s Ames Research Center in Silicon Valley on Monday announced a “Space Act Agreement” with Google that would include collaboration on large-scale data management and massively distributed computing as well as focusing on making the most useful of Nasa’s information available over the internet.

The agreement follows Google’s decision last year to build a 1m square foot campus in a science park linked to the research centre.

There are plans for real-time weather visualisation and forecasting, high-resolution 3-D maps of the moon and Mars and real-time tracking of the International Space Station and the space shuttle.

Google Earth, the software programme that maps the planet, will incorporate Nasa data into future releases.

“This agreement between Nasa and Google will soon allow every American to experience a virtual flight over the surface of the moon or through the canyons of Mars,” said Michael Griffin, Nasa administrator.

Chris Kemp, business development director at Ames, said Nasa had more information on the planet and universe than any other entity in history, but much of it was scattered and difficult to access.

“We are bringing together some of the best research scientists and engineers to form teams to make more of Nasa’s vast information accessible,” he said.

Sergey Brin and Larry Page, Google’s founders, are fascinated with space.

Mr Page is on the board of the X Prize Foundation, which uses competitions to foster breakthroughs in space.

Their Google Maps service includes charts of the moon and they have hired Vint Cerf, who has worked with Nasa on the concept of an interplanetary internet, as their Chief Internet Evangelist.

Copyright The Financial Times Limited 2006

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Tripoli Six Sentenced to Die
The Times     December 20, 2006

Gaddafi faces outrage as nurses on mercy mission are sentenced to die
Charles Bremner in Paris
# Six blamed for giving children HIV
# Second trial after seven years in jail

Five nurses who travelled to Libya to care for sick children were facing death by firing squad last night after being found guilty of deliberately infecting 426 young patients with HIV.

Their conviction, after seven years in jail and two trials, prompted an international outcry and raised the stakes for Colonel Muammar Gaddafi as he tries to regain favour with Europe and the US.

Legal appeals are expected to lead to fresh diplomatic negotiations aimed at a face-saving arrangement for the Libyan leader, who faces domestic pressure for vengeance against an alleged foreign plot to infect children with the virus.

The five Bulgarian women wept as Judge Mahmoud Haouissa pronounced the sentences at the end of a trial that was condemned by scientists, Western governments and human rights organisations.

Ashraf Alhajouj, a Palestinian doctor in his late thirties who received the same sentence, sat impassively behind the bars of the dock. “The verdict doesn’t change anything. We are still innocent,” he said.

The court also ordered the Libyan State to pay the families between $250,000 (£127,000) and $900,000 for each victim. The defendants’ lawyer said that they would appeal.

Aids experts and 114 Nobel prizewinners had called for the swift release of the medical workers. However, relatives of the infected children were delighted. Families celebrated by dancing outside the court. “We are happy,” said Subhy Abdullah, whose daughter Mona, 7, died of Aids contracted at al-Fateh Children’s Hospital in Benghazi.

The death of an eight-year-old boy this week brought to 53 the total of deaths in an epidemic that is seen in Benghazi as a plot to kill Muslims.

However, Ali al-Hasnawi, the Justice Minister, said that there could be “a complete revision of the case”, which had already been tried once before and rejected on appeal. Diplomats see the sentences as a prelude to new contacts between Colonel Gaddafi and Western governments who are keen to keep his country within their fold. Last year the European Union opened the way to a compromise over the affair with a Benghazi action plan. This sent European doctors to the Mediterranean city to provide training and advice in setting up an HIV treatment centre. Most of the surviving children are being treated in hospitals in France and Italy at Colonel Gaddafi’s expense.

The six were part of a larger group of volunteers who went to al-Fateh hospital in 1998. In that year 426 children were confirmed as being HIV-positive. The following year, 19 of the foreigners were arrested, but 13 were later released.

In May 2004 the remaining six — Christiana Valcheva, Dr Alhajouj, Snezhana Dimitrova, 54, Alia Cherveniashka, 51, Nasya Nenova, 40 and Valentina Siropoulo, 47 — were sentenced to death by firing squad for “undermining the security of the State”.

The court ignored testimony from Professor Luc Montagnier — the French doctor who was a co-discoverer of HIV — that the virus was active in the hospital before the nurses began their contracts there.

Colonel Gaddafi fomented anti-foreigner feeling, saying that the CIA or the Israeli Mossad had designed a strain of killer virus and given it to the medical staff to experiment on Libyan children. Now the colonel is seen by experts as using the Benghazi Six as a pawn in his discussions over oil, arms and aircraft, and Middle Eastern diplomacy. 

Twists and turns for the Benghazi Six

February 1999 19 Bulgarian health workers arrested on suspicion of spreading HIV

2000 Five Bulgarian nurses and two doctors — one Bulgarian, one Palestinian — go on trial

2001 Court calls for the death sentence

2002 Three of the accused retract confessions, saying they were given under duress

2003 French specialists testify that HIV was caused by poor hygiene

2004 Nurses and Palestinian doctor sentenced to death; Bulgarian doctor sentenced to four years in jail for currency smuggling. Bulgaria rejects Libyan offer to drop the case in exchange for $10 million for each infected child

2005 Ten Libyan officers accused of torturing the health workers acquitted

Source: agencies

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Researchers identify a 'heartbeat' in Earth's climate

A few years ago, an international team of researchers went to the middle of the Pacific Ocean and drilled down five kilometers below sea level in an effort to uncover secrets about the earth's climate history. They exceeded their expectations and have published their findings in the Dec. 22 edition of the journal Science.

The researchers' drilling produced pristine samples of marine microfossils, otherwise known as foraminifera. Analysis of the carbonate shells of these microfossils, which are between 23 million to 34 million years-old, has revealed that the Earth's climate and the formation and recession of glaciation events in the Earth's history have corresponded with variations in the earth's natural orbital patterns and carbon cycles.

The researchers were particularly interested in these microfossils because they came from the Oligocene epoch, a time in Earth's history known for falling temperatures.

"The continuity and length of the data series we gathered and analyzed allowed for unprecedented insights into the complex interactions between external climate forcing, the global carbon cycle and ice sheet oscillations," said Dr. Jens Herrle, co-author of the paper and a micropaleontology professor at the University of Alberta.

The authors also show how simple models of the global carbon cycle, coupled to orbital controls of global temperature and biological activity, are able to reproduce the important changes observed after the world entered an "ice-house" state about 34 million years ago.

In the early half of the 20th century, Serbian physicist Milutin Milankovitch first proposed that cyclical variations in the Earth-Sun geometry can alter the Earth's climate and these changes can be discovered in the Earth's geological archives, which is exactly what this research team, consisting of members from the United Kingdom, the U.S. and Canada, has done.

"This research is not only concerned with the climate many millions-of-years-ago. Researching and understanding 'extreme' climate events from the geological past allows us to better tune climate models to understand present and future events, and the response to major perturbations of Earth's climate and the global carbon cycle, Herrle added.


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Hubble's main camera stops working
Posted: January 29, 2007

A state-of-the-art camera aboard the Hubble Space Telescope has been knocked out of action by an electrical glitch, curtailing the flow of high-resolution imagery from the aging observatory until new instruments can be installed during a final shuttle servicing mission in 2008.

During that flight, a new camera and spectrograph will be installed, along with six new batteries and a suite of stabilizing gyroscopes that should extend Hubble's scientific life until at least 2013 and possibly longer.

But with the apparent demise of the Advanced Camera for Surveys, installed during the most recent shuttle visit in March 2002, the telescope's most spectacular visible-light images of deep space splendors will be on hold, a disappointment to astronomers around the world.

The camera was engineered to last at lest five years and "we always hope we will meet not only the design lifetime but we'll also get a bonus and that these instruments will live beyond that," Preston Burch, Hubble program manager at NASA's Goddard Space Flight Center in Greenbelt, Md., told reporters today. "So obviously we're disappointed."

Given the complexity of the five-spacewalk servicing mission planned for 2008, NASA is unlikely to add any additional repair work to the astronauts' flight plan.

"If you look at Servicing Mission 4 right now, it's very heavily subscribed," Burch said. "So something would need to come off the repair list (to address the ACS problem) and our preliminary discussions with knowledgeable scientists ... have indicated that's probably not a desirable thing to want to do.

"I wouldn't want to say it's totally impossible if we wanted to put this on a crash basis, but it would require considerable additional effort, time and money to do that. ... At first blush, this doesn't look very attractive."

But Burch said installation of the new Wide Field Camera 3 and the planned repair of a spectrographic instrument already aboard the space telescope will replace and extend the lost capability of the Advanced Camera for Surveys.

In the meantime, engineers are conducting a detailed technical review to make sure the electrical problems that hobbled ACS will not affect the Wide Field Camera 3 or the new Cosmic Origins Spectrograph scheduled for installation in 2008.

For redundancy, the ACS was built with dual power and data systems. On June 30, 2006, an electrical glitch knocked one electrical system, known as Side A, out of action.

The B channel failed Jan. 27, apparently because of an unrelated electrical issue. Pressure sensors detected a presumed puff of smoke when the electrical malfunction occurred and while engineers do not believe the telescope's optical system was contaminated, they do not know exactly what went wrong.

"It's sort of like 'CSI: Greenbelt,'" Burch said in a telephone interview. "We may never know."

Engineers may re-power the A side electronics to permit limited operations with one ACS sensor but this so-called "solar blind" channel is used primarily for low-resolution ultraviolet imaging. Barring a complex orbital repair job, high-resolution visible light pictures will no longer be possible with ACS.

Burch said the B-Side glitch is similar to an electrical problem that earlier affected the Space Telescope Imaging Spectrograph, an instrument shuttle astronauts hope to repair during the 2008 servicing mission.

The similarity in failure modes "is also giving us reason to want to bore into the circuit design and part selection and stuff like that to doubly insure we don't have some kind of latent defect waiting in the wings for COS and WFC-3."

During an earlier review, "we uncovered a lot of workmanship issues ... in the past year and those things have been addressed," Burch said. "It's entirely possible that what just occurred on ACS could very well be a workmanship kind of issue. We don't really know. ... We'll be boring into that very heavily to try to make sure the best we can that the COS and Wide Field 3 are the very best we can make them."

Engineers are hopeful no such problems will be found. With launch now less than two years away, Burch said, "if something like that surfaces, that would be a setback and put a lot of pressure on the program."

Hubble Servicing Mission No. 4 - SM-4 - will be flown aboard the shuttle Atlantis in September 2008. It is the only non-space station mission left on the shuttle manifest, a reflection of the high scientific priority attached to keeping the venerable observatory in operation.

Five back-to-back spacewalks will be required to install six new batteries, six new gyroscopes, the Wide Field Camera 3, the Cosmic Origins Spectrograph and a replacement fine guidance sensor to help the observatory find and track its targets.

The astronauts also will attempt to fix the broken Space Telescope Imaging Spectrograph, a complex task that will require the removal of 111 non-captive screws and the replacement of a power supply circuit board. It is considered the most challenging Hubble repair job since two spacewalking astronauts helped replace a power control unit in 2002.

In addition, Atlantis' crew will install a cooling system to lower the spectrometer's operating temperature, repair degraded thermal insulation and install a fixture that will permit the eventual attachment of a small rocket module to drop it safely out of orbit when it is no longer operational.

The Wide Field Camera 3, installed in place of the current Wide Field Planetary Camera 2, will provide high-resolution optical coverage from the near-infrared region of the spectrum to the ultraviolet.

The Cosmic Origins Spectrograph, sensitive to ultraviolet wavelengths, will take the place of a no-longer-used instrument known as COSTAR that once was used to correct for the spherical aberration of Hubble's primary mirror. All current Hubble instruments are equipped with their own corrective optics

If SM-4 is successful, engineers believe Hubble will remain scientifically productive at least through 2013, an additional five years beyond what could be expected based on the current health of its aging batteries and gyroscopes. With any luck at all, the telescope will still be operating when its replacement, the huge infrared-sensitive James Webb Space Telescope, is launched around 2013.

In the meantime, Hubble's two new science instruments will help the observatory address some of the most fundamental questions in astrophysics and cosmology, including the nature of the so-called dark energy believed to be accelerating the expansion of the universe, and the evolution of galaxies in the wake of the big bang.


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FSU anthropologist confirms 'Hobbit' indeed a separate species
Dean Falk led international team in brain analysis of ancient hominid

TALLAHASSEE, Fla. -- After the skeletal remains of an 18,000-year-old, Hobbit-sized human were discovered on the Indonesian island of Flores in 2003, some scientists thought that the specimen must have been a pygmy or a microcephalic — a human with an abnormally small skull.

Not so, said Dean Falk, a world-renowned paleoneurologist and chair of Florida State University's anthropology department, who along with an international team of experts created detailed maps of imprints left on the ancient hominid's braincase and concluded that the so-called Hobbit was actually a new species closely related to Homo sapiens.

Now after further study, Falk is absolutely convinced that her team was right and that the species cataloged as LB1, Homo floresiensis, is definitely not a human born with microcephalia — a somewhat rare pathological condition that still occurs today. Usually the result of a double-recessive gene, the condition is characterized by a small head and accompanied by some mental retardation.

"We have answered the people who contend that the Hobbit is a microcephalic," Falk said of her team's study of both normal and microcephalic human brains published in the Jan. 29 issue of the journal PNAS (Proceedings of the National Academy of Sciences of the United States).

The debate stemmed from the fact that archaeologists had found sophisticated tools and evidence of a fire near the remains of the 3-foot-tall adult female with a brain roughly one-third the size of a contemporary human.

"People refused to believe that someone with that small of a brain could make the tools. How could it be a sophisticated new species?"

But that's exactly what it is, according to Falk, whose team had previously created a "virtual endocast" from a three-dimensional computer model of the Hobbit's braincase, which reproduces the surface of the brain including its shape, grooves, vessels and sinuses. The endocasts revealed large parts of the frontal lobe and other anatomical features consistent with higher cognitive processes.

"LB1 has a highly evolved brain," she said. "It didn't get bigger, it got rewired and reorganized, and that's very interesting."

In this latest study, the researchers compared 3-D, computer-generated reconstructions of nine microcephalic modern human brains and 10 normal modern human brains. They found that certain shape features completely separate the two groups and that Hobbit classifies with normal humans rather than microcephalic humans in these features. In other ways, however, Hobbit's brain is unique, which is consistent with its attribution to a new species.

Comparison of two areas in the frontal lobe, the temporal lobe and the back of the brain show the Hobbit brain is nothing like a microcephalic's and is advanced in a way that is different from living humans. In fact, the LB1 brain was the "antithesis" of the microcephalic brain, according to Falk, a finding the researchers hope puts this part of the Hobbit controversy to rest.

It's time to move on to other important questions, Falk said, namely the origin of this species that co-existed at the same time that Homo sapiens was presumed to be the Earth's sole human inhabitant.

"It's the $64,000 question: Where did it come from?" she said. "Who did it descend from, who are its relatives, and what does it say about human evolution? That's the real excitement about this discovery."


Falk's co-authors on the PNAS paper, "Brain shape in human microcephalics and Homo floresiensis," are Charles Hildebolt, Kirk Smith and Fred Prior of the Washington University School of Medicine in St. Louis; M.J. Morwood of the University of New England in Australia; Thomas Sutikna, E. Wayhu Saptomo and Jatmiko of the Indonesian Centre for Archaeology in Indonesia; Herwig Imhof of the Medical University of Vienna, Austria; and Horst Seidler of the University of Vienna, Austria.


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Physicists find way to 'see' extra dimensions

MADISON - Peering backward in time to an instant after the big bang, physicists at the University of Wisconsin-Madison have devised an approach that may help unlock the hidden shapes of alternate dimensions of the universe.

A new study demonstrates that the shapes of extra dimensions can be "seen" by deciphering their influence on cosmic energy released by the violent birth of the universe 13 billion years ago. The method, published today (Feb. 2) in Physical Review Letters, provides evidence that physicists can use experimental data to discern the nature of these elusive dimensions - the existence of which is a critical but as yet unproven element of string theory, the leading contender for a unified "theory of everything."

Scientists developed string theory, which proposes that everything in the universe is made of tiny, vibrating strings of energy, to encompass the physical principles of all objects from immense galaxies to subatomic particles. Though currently the front-runner to explain the framework of the cosmos, the theory remains, to date, untested.

The mathematics of string theory suggests that the world we know is not complete. In addition to our four familiar dimensions - three-dimensional space and time - string theory predicts the existence of six extra spatial dimensions, "hidden" dimensions curled in tiny geometric shapes at every single point in our universe.

Don't worry if you can't picture a 10-dimensional world. Our minds are accustomed to only three spatial dimensions and lack a frame of reference for the other six, says UW-Madison physicist Gary Shiu, who led the new study. Though scientists use computers to visualize what these six-dimensional geometries could look like (see image), no one really knows for sure what shape they take.

The new Wisconsin work may provide a long-sought foundation for measuring this previously immeasurable aspect of string theory.

According to string theory mathematics, the extra dimensions could adopt any of tens of thousands of possible shapes, each shape theoretically corresponding to its own universe with its own set of physical laws.

For our universe, "Nature picked one - and we want to know what that one looks like," explains Henry Tye, a physicist at Cornell University who was not involved in the new research.

Shiu says the many-dimensional shapes are far too small to see or measure through any usual means of observation, which makes testing this crucial aspect of string theory very difficult. "You can theorize anything, but you have to be able to show it with experiments," he says. "Now the problem is, how do we test it?"

He and graduate student Bret Underwood turned to the sky for inspiration.

Their approach is based on the idea that the six tiny dimensions had their strongest influence on the universe when it itself was a tiny speck of highly compressed matter and energy - that is, in the instant just after the big bang.

"Our idea was to go back in time and see what happened back then," says Shiu. "Of course, we couldn't really go back in time."

Lacking the requisite time machine, they used the next-best thing: a map of cosmic energy released from the big bang. The energy, captured by satellites such as NASA's Wilkinson Microwave Anisotropy Probe (WMAP), has persisted virtually unchanged for the last 13 billion years, making the energy map basically "a snapshot of the baby universe," Shiu says. The WMAP experiment is the successor to NASA's Cosmic Background Explorer (COBE) project, which garnered the 2006 Nobel Prize in physics.

Just as a shadow can give an idea of the shape of an object, the pattern of cosmic energy in the sky can give an indication of the shape of the other six dimensions present, Shiu explains.

To learn how to read telltale signs of the six-dimensional geometry from the cosmic map, they worked backward. Starting with two different types of mathematically simple geometries, called warped throats, they calculated the predicted energy map that would be seen in the universe described by each shape. When they compared the two maps, they found small but significant differences between them.

Their results show that specific patterns of cosmic energy can hold clues to the geometry of the six-dimensional shape - the first type of observable data to demonstrate such promise, says Tye.

Though the current data are not precise enough to compare their findings to our universe, upcoming experiments such as the European Space Agency's Planck satellite should have the sensitivity to detect subtle variations between different geometries, Shiu says.

"Our results with simple, well-understood shapes give proof of concept that the geometry of hidden dimensions can be deciphered from the pattern of cosmic energy," he says. "This provides a rare opportunity in which string theory can be tested."

Technological improvements to capture more detailed cosmic maps should help narrow down the possibilities and may allow scientists to crack the code of the cosmic energy map - and inch closer to identifying the single geometry that fits our universe.

The implications of such a possibility are profound, says Tye. "If this shape can be measured, it would also tell us that string theory is correct."


The new work was funded by grants from the National Science Foundation, the U.S. Department of Energy, and the Research Corp.


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The first over-the-counter weight-loss pill won approval from US health officials on Wednesday,

 despite health concerns from consumer groups.

The drug orlistat – made by GlaxoSmithKline (GSK) and sold as Alli – reduces the amount of fat the body absorbs from food. It is a half-dose version of a prescription medicine called Xenical, sold by Roche.

The Food and Drug Administration (FDA) approved Alli for use by overweight adults and stressed the drug should be combined with a reduced-calorie, low-fat diet and exercise. "This drug is only going to be effective if used in conjunction with a weight-loss programme," said Charles Ganley, FDA's head of non-prescription drug products.

The drug's packaging will say that for every 5 pounds lost through diet, Alli can help a person drop 2 or 3 pounds more. According to Ganley, studies by GSK found 28% of Alli users lost 5% to 10% of their body weight over six months, compared to about 18% who took a placebo.

Alli works by reducing the amount of the fat that the body absorbs by about one-quarter. The undigested fat is eliminated through bowel movements, which can cause side effects such as gas, diarrhoea and an oily discharge.

Vitamin supplements
Eating a low-fat diet can reduce the side effects, GSK and the FDA said in a statement. Alli users were also advised to take a multivitamin at bedtime to make up for the possible loss of certain nutrients, the FDA added.

Alli is now the only non-prescription weight-loss remedy with FDA approval, although many companies sell over-the-counter supplements that claim weight-loss benefits.

Consumer group Public Citizen, which has urged a ban on prescription Xenical, said Alli should not have been approved because of precancerous colon lesions linked to the drug in animal studies. The group also described the drug's benefits as "marginal."

Alli will cost about $2 a day and be in stores by summer, said GSK’s Steven Burton. Glaxo previously estimated that five to six million Americans would buy Alli over the counter. Burton said the potential market was likely to be larger, but declined to give sales projections. news service
« Last Edit: 08/02/2007 18:44:04 by ukmicky »

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Narcolepsy hints at drug for insomniacs

Trouble sleeping? Insomniacs can take heart from a new drug that makes the brain enter a state similar to narcolepsy.

People with narcolepsy suddenly and unexpectedly fall asleep, probably because of defective orexin neurons in the hypothalamus. These normally release proteins called orexins that are needed to keep us awake.

Catherine Brisbare-Roch at Actelion Pharmaceuticals in Allschwil, Switzerland, and her colleagues have developed a drug that blocks orexin receptors, in turn reducing the neurons' firing rate. Preliminary studies suggest that the drug promotes sleepiness in rats, dogs and people (Nature Medicine, DOI: 10.1038/nm1544).

Unlike other sleeping pills, the drug also increases the time spent in REM sleep, when the brain is thought to organise memories, so it may not cause the forgetfulness and memory disruption linked to regular sleeping pill use

From issue 2589 of New Scientist magazine, 06 February 2007

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Excellent article..Thanks Michael

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LSU professor resolves Einstein's twin paradox

BATON ROUGE – Subhash Kak, Delaune Distinguished Professor of Electrical and Computer Engineering at LSU, recently resolved the twin paradox, known as one of the most enduring puzzles of modern-day physics.

First suggested by Albert Einstein more than 100 years ago, the paradox deals with the effects of time in the context of travel at near the speed of light. Einstein originally used the example of two clocks – one motionless, one in transit. He stated that, due to the laws of physics, clocks being transported near the speed of light would move more slowly than clocks that remained stationary. In more recent times, the paradox has been described using the analogy of twins. If one twin is placed on a space shuttle and travels near the speed of light while the remaining twin remains earthbound, the unmoved twin would have aged dramatically compared to his interstellar sibling, according to the paradox.

“If the twin aboard the spaceship went to the nearest star, which is 4.45 light years away at 86 percent of the speed of light, when he returned, he would have aged 5 years. But the earthbound twin would have aged more than 10 years!” said Kak.

The fact that time slows down on moving objects has been documented and verified over the years through repeated experimentation. But, in the previous scenario, the paradox is that the earthbound twin is the one who would be considered to be in motion – in relation to the sibling – and therefore should be the one aging more slowly. Einstein and other scientists have attempted to resolve this problem before, but none of the formulas they presented proved satisfactory.

Kak’s findings were published online in the International Journal of Theoretical Science, and will appear in the upcoming print version of the publication. “I solved the paradox by incorporating a new principle within the relativity framework that defines motion not in relation to individual objects, such as the two twins with respect to each other, but in relation to distant stars,” said Kak. Using probabilistic relationships, Kak’s solution assumes that the universe has the same general properties no matter where one might be within it.

The implications of this resolution will be widespread, generally enhancing the scientific community’s comprehension of relativity. It may eventually even have some impact on quantum communications and computers, potentially making it possible to design more efficient and reliable communication systems for space applications.


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Scientists elucidate the origin of the darkest galaxies in the universe

Ghostly galaxies composed almost entirely of dark matter speckle the universe. Unlike normal galaxies, these extreme systems contain very few stars and are almost devoid of gas. Most of the luminous matter, so common in most galaxies, has been stripped away, leaving behind a dark matter shadow. These intriguing galaxies-known as dwarf spheroidals-are so faint that, although researchers believe they exist throughout the universe, only those relatively close to Earth have ever been observed. And until recently, no scientific model proposed to unravel their origin could simultaneously explain their exceptional dark matter content and their penchant for existing only in close proximity to much larger galaxies.

Now, Stelios Kazantzidis, a researcher at Stanford University's Kavli Institute for Particle Astrophysics and Cosmology (KIPAC), in collaboration with Lucio Mayer of the Swiss Federal Institute of Technology in Zurich and the University of Zurich, Chiara Mastropietro of the University of Munich in Germany and James Wadsley of McMaster University in Canada, has developed an elegant explanation for how galaxies come to be dominated by dark matter. Kazantzidis, who completed part of the study as a fellow at the University of Chicago's Kavli Institute for Cosmological Physics, reports his findings in the Feb. 15 issue of Nature.

"These results are so exciting because they are based on a combination of physical effects that has never before been postulated," said Kazantzidis. "This is one step toward a more complete understanding of the formation of structure in the universe, which is one of the fundamental goals of astrophysics."

Using supercomputers to create novel simulations of galaxy formation, Kazantzidis and his collaborators found that a dark matter-dominated galaxy begins life as a normal system. But when it approaches a much more massive galaxy, it simultaneously encounters three environmental effects-"ram pressure," "tidal shocking" and the cosmic ultraviolet background-that transform it into a mere dark-matter shadow of its former self.

About 10 billion years ago, when the gas-rich progenitors of dark matter-dominated galaxies originally fell into the Milky Way, the universe was hot with a radiation called the cosmic ultraviolet background. As a small satellite galaxy traveled along its elliptical path around a more massive galaxy, called the host, this radiation made the gas within the smaller galaxy hotter. This state allowed ram pressure-a sort of "wind resistance" a galaxy feels as it speeds along its path-to strip away the gas within the satellite galaxy.

Simultaneously, as the satellite galaxy moved closer to the massive system, it encountered the overwhelming gravitational force of the much larger mass. This force wrenched luminous stars from the small galaxy. Over billions of years of evolution, the satellite passed by the massive galaxy several times as it traversed its orbital path. Each time its stars shook and the satellite lost some of them as a result of a mechanism called tidal shocking. These effects conspired to eventually strip away nearly all the luminous matter-gas and stars-and left behind only a dark-matter shadow of the original galaxy.

The dark matter, on the other hand, was nongaseous and therefore unaffected by the ram pressure force or the cosmic ultraviolet background, the scientists posit. It did experience tidal shocking, but this force alone was not strong enough to pull away a substantial amount of dark matter.

The numerical simulations conducted by Kazantzidis and his collaborators constitute the most extensive calculations ever performed on this topic, consuming up to two months of supercomputing time each at the University of Zurich, the Pittsburgh Supercomputing Center and elsewhere.

"Computer models of galaxy formation in the last decade or so have focused on modeling the properties of dark matter rather than those of the more familiar baryonic [luminous] matter," said co-author Mayer. "Instead, our work suggests that we cannot understand the origin of galaxies without modeling the detailed physics of baryonic matter, even in a dark matter-dominated universe."

The scientists say this new understanding of the origin of the darkest galaxies in the universe may soon lead to fundamental insights into the nature of dark matter.

"Elucidating the nature of dark matter is one of the grandest challenges of modern cosmology," said Kazantzidis. "In the next several years, numerous experiments will attempt to detect dark matter using dwarf spheroidal galaxies as targets." Kazantzidis' work will benefit these studies by offering a better explanation of the origin of ghostly galaxies.

Mystery of the missing satellites

Additionally, the work may help to explain a long-standing discrepancy between theory and observation. The leading modern cosmological model, Lambda Cold Dark Matter ((CDM), predicts that many more small galaxies surround massive galaxies like the Milky Way and Andromeda than are currently observed. This mismatch, which is often referred to as the "missing satellites problem," has been traditionally regarded as one of the toughest challenges to the (CDM paradigm. Kazantzidis' work suggests that the process by which small galaxies are stripped of their luminous matter is common, and implies that the "missing" galaxies could exist in the form of dark matter-dominated satellites.

"These galaxies could just be too dark to detect," he said. "But their possible existence will substantially alleviate the missing satellites problem with profound implications for the predictive power of the (CDM theory." Coincidentally, in the last few months, one of the most advanced observational programs ever undertaken, the Sloan Digital Sky Survey, has revealed in the vicinity of the Milky Way a number of what appear to be ultra-faint satellite galaxies. If this finding is confirmed by follow-up observations and analysis, these newly discovered systems would be explained by Kazantzidis' calculations and would contribute to solving the long-standing missing satellites problem, he says.



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Chimpanzees 'hunt using spears' 

Chimpanzees in Senegal have been observed making and using wooden spears to hunt other primates, according to a study in the journal Current Biology.
Researchers documented 22 cases of chimps fashioning tools to jab at smaller primates sheltering in cavities of hollow branches or tree trunks.

The report's authors, Jill Pruetz and Paco Bertolani, said the finding could have implications for human evolution. Chimps had not been previously observed hunting other animals with tools.

Pruetz and Bertolani made the discovery at their research site in Fongoli, Senegal, between March 2005 and July 2006.

I hope no-one tells Charlton Heston, he may shoot "the filthy apes".   ;D

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Study reveals leaks in Antarctic 'plumbing system'
Posted: February 24, 2007

WASHINGTON - Scientists using NASA satellites have discovered an extensive network of waterways beneath a fast-moving Antarctic ice stream that provide clues as to how "leaks" in the system impact sea level and the world's largest ice sheet. Antarctica holds about 90 percent of the world's ice and 70 percent of the world's reservoir of fresh water.

With data from NASA satellites, a team of scientists led by research geophysicist Helen Fricker of the Scripps Institution of Oceanography, La Jolla, Calif., detected for the first time the subtle rise and fall of the surface of fast-moving ice streams as the lakes and channels nearly a half-mile of solid ice below filled and emptied. Results were presented at the annual meeting of the American Association for the Advancement of Science (AAAS) in San Francisco. The study was published in the Feb. 16 issue of Science magazine.

"This exciting discovery of large lakes exchanging water under the ice sheet surface has radically altered our view of what is happening at the base of the ice sheet and how ice moves in that environment," said co-author Robert Bindschadler, chief scientist of the Laboratory for Hydrospheric and Biospheric Sciences at NASA's Goddard Space Flight Center, Greenbelt, Md.

"NASA's state-of-the-art satellite instruments are so sensitive we are able to capture an unprecedented three-dimensional look at the system beneath the thick ice sheet and measure from space changes of a mere 3 feet in its surface elevation. That is like seeing an elevation change in the thickness of a paperback book from an airplane flying at 35,000 feet."

The surface of the ice sheet appears stable to the naked eye, but because the base of an ice stream is warmer, water melts from the basal ice to flow, filling the system's "pipes" and lubricating flow of the overlying ice. This web of waterways acts as a vehicle for water to move and change its influence on the ice movement.

Moving back and forth through the system's "pipes" from one lake to another, the water stimulates the speed of the ice stream's flow a few feet per day, contributing to conditions that cause the ice sheet to either grow or decay. Movement in this system can influence sea level and ice melt worldwide.

"There's an urgency to learning more about ice sheets when you note that sea level rises and falls in direct response to changes in that ice," Fricker said. "With this in mind, NASA's ICESat, Aqua and other satellites are providing a vital public service."

In recent years, scientists have discovered more than 145 subglacial lakes, a smaller number of which composes this "plumbing system" in the Antarctic. Bindschadler and Fricker; Ted Scambos of the National Snow and Ice Data Center in Boulder, Colo.; and Laurence Padman of Earth and Space Research in Corvallis, Ore.; observed water discharging from these under-ice lakes into the ocean in coastal areas. Their research has delivered new insight into how much and how frequently these waterways "leak" water and how many connect to the ocean.

The study included observations of a subglacial lake the size of Lake Ontario buried under an active area of west Antarctica that feeds into the Ross Ice Shelf. The research team combined images from the Moderate Resolution Imaging Spectroradiometer (MODIS) instrument aboard NASA's Aqua satellite and data from the Geoscience Laser Altimeter System (GLAS) on NASA's Ice Cloud and Land Elevation Satellite (ICESat) to unveil a multi-dimensional view of changes in the elevation of the icy surface above the lake and surrounding areas during a three-year period. Those changes suggest the lake drained and that its water relocated elsewhere.

MODIS continuously takes measurements of broad-sweeping surface areas at three levels of detail, revealing the outline of under-ice lakes. ICESat's GLAS instrument uses laser altimetry technology to measure even the smallest of elevation changes in the landscape of an ice sheet. Together, data from both have been used to create a multi-year series of calibrated surface reflectance images, resulting in a new technique called satellite image differencing that emphasizes where surface slopes have changed.


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Detection of a colliding-wind beyond the Milky Way

Posted: February 25, 2007

Imagine two stars with winds so powerful that they eject an Earth's worth of material roughly once every month. Next, imagine those two winds colliding head-on. Such titanic collisions produce multimillion-degree gas, which radiates brilliantly in X-rays. Astronomers have conclusively identified the X-rays from about two-dozen of these systems in our Milky Way. But they have never seen one outside our galaxy - until now.

Thanks to the European Space Agency's XMM-Newton X-ray observatory, with help from NASA's Chandra X-ray Observatory, an international team led by Dr Yael Naze of the Universite de Liege in Belgium has found such a system in a nearby galaxy. This galaxy, the Small Magellanic Cloud, orbits the Milky Way and is located about 170 000 light-years from Earth.   

The binary system, known as HD 5980, contains two extremely massive stars, 'weighing' about 50 and 30 times the mass of the Sun. Each star radiates more than a million times as much light as the Sun, meaning they put out more light in one minute than our host star generates in an entire year.

The sheer photon pressure of this incredible outpouring of light blows off gas from each star in a supersonic 'wind'. These winds are so powerful that they carry away roughly an Earth mass each month, a rate 10 thousand million times greater than the solar wind, and at a speed 5 times faster than the solar wind itself.

HD 5980's two stars are separated by only about 90 million kilometres, roughly half Earth's average distance from the Sun. "These stars are so close to each other that if they were in our solar system they could fit inside the orbit of Venus," says Naze. As a result, the winds smash into each other with tremendous force, heating the gas and generating enormous numbers of X-rays.

"The system emits about 10 times more energy in X-rays alone than the Sun radiates over the entire spectrum," says team member Dr Michael F. Corcoran, a scientist with the Universities Space Research Association at NASA's Goddard Space Flight Center in Greenbelt, Maryland.

Using data from Chandra, the same team first reported HD 5980's highly energetic X-ray emission in 2002. But its origin was uncertain. Data taken from 2000 to 2005 with XMM-Newton shows that it is indeed produced by a wind collision.

The stars orbit each other every 20 days in a plane that is edge-on to Earth's line of sight, so the stars periodically eclipse each other. The wind collision is thus seen from different angles and through different amounts of material. XMM-Newton saw the X-ray emission rise and fall in a repeatable, predictable pattern.

"Similar X-ray variability from massive binaries inside the Milky Way have been detected, but this is the first indisputable evidence for the phenomenon outside our galaxy," says Naze. "This discovery highlights the great capabilities of modern X-ray observatories."

XMM-Newton has the largest mirrors of any X-ray observatory ever flown, and the sheer size of these mirrors allowed astronomers to monitor this distant system. HD 5980 itself is surrounded by hot interstellar material that creates a diffuse X-ray glow that makes the object difficult to study. "The Chandra data allowed us to pinpoint HD 5980 and resolve the system from the diffuse emission," says Corcoran.

HD 5980 is one of the Small Magellanic Cloud's brightest stars. Situated on the periphery of the star cluster NGC 346, the two stars are nearing the end of their lives and will eventually explode as supernovae. The more massive star, HD 5980A, is passing through a Luminous Blue Variable (LBV) phase - a short-lived, erratic stage that only the most massive stars go through. The most well-known LBV in our galaxy, Eta Carinae, produced a giant outburst that was recorded by astronomers in the 1840s. HD 5980A experienced a smaller-scale outburst that was seen in 1993-94. Its companion, HD 5980B, is an evolved Wolf-Rayet star that has already ejected much of its original envelope.

"It's interesting to be able to study an extragalactic colliding-wind binary like HD 5980 as if it were in our own galaxy", says Corcoran. "Colliding winds provide an important handle on how massive stars shed material. Being able to study them in external galaxies means we can study the effects of different compositions and environments on how these massive stars evolve. From the XMM-Newton data, we can study the delicate balance between the two winds, and determine the changing strength of the winds."

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New coating is virtual black hole for reflections

Nonreflecting material may help solar cells catch more of the sun's rays.

Researchers have created an anti-reflective coating that allows light to travel through it, but lets almost none bounce off its surface. At least 10 times more effective than the coating on sunglasses or computer monitors, the material, which is made of silica nanorods, may be used to channel light into solar cells or allow more photons to surge through the surface of a light-emitting diode (LED).

Publishing in the March 1, 2007, Nature Photonics, lead author Jong Kyu Kim and a team from Rensselaer Polytechnic Institute in Troy, N.Y., reveal how they crafted the coating, which reflects almost as little light as do molecules of air.

Guided by National Science Foundation-supported electrical engineer Fred Schubert, the researchers developed a process based on an already common method for depositing layers of silica, the building block of quartz, onto computer chips and other surfaces.

The method grows ranks of nanoscale rods that lie at the same angle. That degree of the angle is determined by temperature. Under a microscope, the films look like tiny slices of shag carpet.

By laying down multiple layers, each at a different angle, the researchers created thin films that are uniquely capable of controlling light. With the right layers in the right configuration, the researchers believe they can even create a film that will reflect no light at all.

One critical application for the material is in the development of next-generation solar cells. By preventing reflections, the coating would allow more light, and more wavelengths of light, to transmit through the protective finish on a solar cell surface and into the cell itself. Engineers may be able to use such a technique to boost the amount of energy a cell can collect, bypassing current efficiency limits.

Another application would involve coating LEDs to eliminate reflections that cut down the amount of light the LED can emit. The researchers hope the efficiency gains could allow the light sources to compete more effectively with fluorescent and incandescent bulbs. So, they will next focus their attention on solid state lighting.


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