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Comet Dust Tells Creation Story
Irene Klotz, Discovery News
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Dec. 14, 2006 — Comets may live most of their lives in the solar system's deep-freeze, but it wasn't always that way.

The results from the first mission to return a comet sample show that mixed in with the ice and interstellar dust grains that many scientists expected to find are particles forged in the nuclear fires of the inner solar nebula.

"We found that the comet is a real grab-bag of stuff that must have formed in many different environments, including very close to the sun," said Michael Zolensky, a NASA scientist at the Johnson Space Center in Houston and a co-author in a series of papers about the Stardust mission that appear in this week's Science.
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NASA dispatched a probe in 2004 that, two years later, flew by Comet Wild-2 to trap samples popping off the comet's core. The return capsule parachuted to Earth in January.

The Stardust science team invited experts from around the world to participate in the analysis, resulting in an early and thorough first look at what the comet samples contain.

The prevailing theory had been that comets were made of particles found in the outer regions of the solar system: ices, cold minerals, bits of matter from exploded stars.

Instead the searchers found particles that formed throughout the solar nebula, including the super-heated regions near the sun.

Stardust lead scientist Donald Brownlee, with the University of Washington, estimates about 10 percent of Comet Wild-2 contains material forged in the hottest parts of the solar system.


"We really didn't expect to find anything from the inner solar system. Instead, it showed up in the second particle we looked at," Brownlee said.

Another surprise was the lack of minerals showing interaction with water.

"Some people thought we'd see a lot of evidence for interaction with liquid water, which is important because the comet has all kinds of organics," Zolensky said. "If it spent some millions of years warm with liquid water inside and organics, there's a chance that organic reactions were going on in the comet."
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He added: "Some folks have even talked about viruses coming from comets. We saw zero evidence for that."

There were none from Comet Wild 2, anyway.

Though the bits of material retrieved from Comet Wild 2 are the only samples of their kind, other studies — such as the July 2005 Deep Impact mission, which remotely analyzed ejected material from Comet Tempel 1 — have turned up different results.

"All the comets we've visited so far all look different," Zolensky said. "It tells us they all have different histories."

Saturn Moon Probably Dry
Alicia Chang, Associated Press
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Dec. 14, 2006 —New research casts doubt on the existence of water near the surface of a tiny Saturn moon — a finding that, if confirmed, could set back the hunt for extraterrestrial life.

Earlier this year, the international Cassini spacecraft orbiting Saturn caused a stir when it spied what appeared to be Yellowstone-like geysers spouting from the south pole of Enceladus. Scientists speculated the eruptions were driven by shallow pools of water lurking just below the icy surface.

In an alternative view published in Friday's issue of the journal Science, other researchers propose that buried ice clathrates — not liquid water — are responsible for releasing the towering plumes through a sudden tectonic shift in the crust that causes cracks in the ice and gas to vent.
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The study doesn't address whether liquid might be present anywhere else on the moon, said lead author Susan Kieffer, a planetary scientist at the University of Illinois at Urbana-Champaign, who has studied geysers on Earth and on the moons of Jupiter and Neptune.

"We didn't go into this trying to disprove liquid water," said Kieffer, adding that in her model, "there is no liquid water required."

The alternative theory shows scientists still don't really know what causes plumes to rise from Enceladus and until that's sorted out, it's premature to send a spacecraft to search for extraterrestrial life, said Bruce Jakosky, an astrobiologist at the University of Colorado at Boulder.

Jakosky noted that if liquid water is not easily accessible on Enceladus, it doesn't bode well for life.

"This would mean that Enceladus would not be a viable place for life. It makes a big difference!" he wrote in an e-mail.


Cassini found the geysers were a mix of water vapor and ice particles containing significant amounts of carbon dioxide and trace amounts of methane. Kieffer said methane cannot completely dissolve in liquid water, but can exist in ice clathrates, lattice-like structures that trap water ice and organic particles.

Carolyn Porco, a Cassini scientist who first raised the idea of an underground water reservoir on Enceladus, said that while the new model sounds plausible, it doesn't rule out her own model or the possibility of water flowing further down.

She also said the new study shouldn't deter any future missions from probing whether microbial life can exist in such an environment.
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"There's reason to believe that there's enough warmth on Enceladus to support liquid water," Porco said.

Enceladus, at only 300 miles wide, was a virtual unknown until Cassini imaged the jets bubbling from a warm zone in its southern polar region. The discovery vaulted the tiny moon into an exclusive club of celestial bodies that might favor life. Scientists generally agree that Mars and Jupiter's icy moons might have — or once had — conditions conducive to life.

Chair Made From Recycled Hair
Jennifer Viegas, Discovery News
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Dec. 14, 2006 — Hair trimmings at barbershops and beauty salons are often swept up and discarded. But a former London hairdresser, who is now a researcher at London South Bank University, has found a use for the excess cuttings — a chair made out of human hair.

In the future, additional products, such as structural beams, shoes, clothing, mascara and boat parts, may also be made out of human hair, which is "a cut above" fiberglass and many other petroleum-based products, according to the chair's inventor, Ronald Thompson.
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"This free, sustainable and abundant resource can be molded into any shape and mixed with any matrix," said Thompson, who was an assistant hairdresser for famed stylists John Frieda and Nicky Clarke.

"It is versatile, waterproof, non-conductive, corrosion free, fire resistant, tough, strong, durable and is able to compete with products, such as medium-density fiberboard, fiberglass, polymers and aluminum," he added.

Thompson, who has styled the locks of many Miss World contestants, was inspired to recycle hair after working on the set of the film "Batman Begins." He stretched a piece of fiberglass, which snapped. He did the same thing to a strand of hair, which withstood far more stretching.

He learned that one strand of hair can support 8,750 times its own weight, a head of hair can support over 13 tons and that hair can double its own length before breaking.

Lab work led to a product called Pilius X, the structural basis for the chair and his other proposed inventions. It's a hair-based bio-polymer mixed with a recyclable bio-resin.

Like hair itself, Pilius X can be dyed to almost any color.

Thompson's furniture creation — the ergodynamic "Stiletto chair" — contains 4.5 pounds of human hair cuttings. Since the average haircut produces just 0.17 ounce of hair every 6 weeks, it would take an individual 46 years to have enough hair to make a single chair.

Still, the former stylist isn't short on materials.

"The average salon produces this amount of hair cuttings every two weeks," he explained. "Well over 220,000 tons are produced in the United Kingdom per year, while millions of tons are produced worldwide each year."


Julie Muir, president of the California Resource Recovery Association, a non-profit dedicated to promoting recycling projects, was surprised to learn of the chair. Muir commented "it's a great use for hair, which would probably otherwise wind up in a landfill where it would contribute to methane gas, a greenhouse gas linked to global warming."

Muir pointed out that others have found different uses for discarded hair, including some farmers who sprinkle it on the ground to scare away wild boars.

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"The hair retains its human scent, so that's probably what scares the boars," she told Discovery News.

Muir thinks the hair chair is a fun, but also important, idea.

"We need more creative solutions like this for waste problems," she said. "We'd like to see all organic materials out of landfills, and this is just one step toward that goal."

The human hair chair, which is coated with bronze, is priced at just over $15,000. Thompson may develop less expensive models, so the human hair chair could very well be on more holiday gift lists in the not-too-distant future.

U.S. Breast Cancer Rates Plummet
Marilynn Marchione, Associated Press
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Dec. 14, 2006 — In a startling turnaround, breast cancer rates in the United States dropped dramatically in 2003, and experts said they believe it is because many women stopped taking hormone pills.

The 7.2 percent decline came a year after a big federal study linked menopause hormones to a higher risk of breast cancer, heart disease and other problems. Within months, millions of women stopped taking estrogen and progestin pills.

A new analysis of federal cancer statistics, presented Thursday at a breast cancer conference in Texas, revealed the drop in tumors.
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About 200,000 cases of breast cancer had been expected in 2003; the drop means that about 14,000 fewer women actually were diagnosed with the disease.

Because breast cancer takes years to form, experts think that withdrawing hormones mostly caused small tumors that had been growing to stop or shrink, making them no longer detectable on mammograms. Whether this is true or will result in fewer cases over the long run will take more time to tell.

The next set of cancer statistics, for 2004, is due out in April.

Why do doctors think the 2003 drop is largely due to hormones?

Cases declined most among women 50 and older, with tumors whose growth is fueled by estrogen — the age group and type of cancer most affected by hormone use.

The drop also was seen in every single cancer registry that reports information to the federal government.

Researchers looked for a similar drop in other cancers, which could indicate something other than hormones was at work, "and we didn't see anything," said Kathy Cronin, a National Cancer Institute statistician who worked on the analysis.

When the 2003 numbers were first released a few months ago, they were grouped with 2001 and 2002 and portrayed as a leveling off of breast cancer after decades of steady rise. The big single-year drop was not pointed out because experts did not want to make too much of it without knowing whether the trend would continue.

However, Dr. Peter Ravdin, a breast cancer specialist at the University of Texas M.D. Anderson Cancer Center who led the new analysis, said the single year drop is important regardless, because it was so huge and came after years of steady increases.

"We don't know about whether or not it's going to be a trend but we know for this year it was a significant effect," he said.

Doctors estimate that half of women who were taking hormones stopped after July 2002, when the federal Women's Health Initiative study was halted because more women taking estrogen/progestin pills developed breast cancer or heart problems.

That led to new warning labels on the drugs and doctor groups urging women to use the lowest dose for the shortest time possible.

"The hypothesis is entirely plausible, that the discontinuation of hormone replacement therapy could be having an effect," said Dr. Michael Thun of the American Cancer Society.

New Breast Scan Doesn't Squeeze
Tracy Staedter, Discovery News
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Dec. 14, 2006 — Surely, every woman who has ever had her breasts squeezed between two plastic plates during a mammography has thought, "There's got to be a better way."

There just might be.

An ongoing study being conducted by physicians at the University of Rochester and the Elizabeth Wende Breast Clinic is showing promise for a new technology called Cone Beam Breast Computed Tomography.
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So far, the technique has produced breast images that are just as good as — and in some cases, better than —those taken with mammography with a similar X-ray dose but without the need for any uncomfortable squeezing.

And while it may not initially replace mammography altogether, it could add another layer of confidence to diagnosing suspicious abnormalities in the breast.

"We think at least 15 percent of cancers can't be diagnosed because they are hiding," said physician Avice O'Connell, director of women's imaging at the University of Rochester's Medical Center, co-author in the study.

That may be part of the reason why breast cancer remains the biggest cancer killer of women, after lung cancer, with 270,000 cases diagnosed and 40,000 deaths annually in the United States alone.

Finding diseased tissue is a challenge because each woman's breast differs in tissue composition. For example, cancer is somewhat easier to spot in breasts with lots of fatty tissue and more difficult to spot in breasts that have less fat and more of the fibrous glandular tissue that produces milk.

If a woman has a mammogram and the clinician spots something suspicious, the patient may be asked to undergo an ultrasound and then a biopsy.

In at least 75 to 80 percent of the cases, the suspicious masses turn out to be nothing to worry about, said Daniel Kopans, professor of radiology and director of breast imaging at the Massachusetts General Hospital in Boston. Kopans is not associated with the study.

On the other side of the coin, even the best mammographers under the best conditions will miss 15 percent of tumors, said O'Connell.

"It's like trying to find a snowman in a snowstorm," she said. "You can't see it until you come up close to it."

Cone Beam CT has the potential to significantly improve diagnosis.


Like conventional CT scans, the Cone Beam uses X-rays to produce three-dimensional images of muscles, organs, and other soft tissue. However, whereas conventional CT technology emits X-rays in a narrow beam, Cone Beam delivers them in a wide cone, scanning all of the tissue at once.

During the exam, the patient lies face down on a table and allows her breast to hang freely through a hole in the table. Below the table is the imager, a donut-shaped device that encircles the breast. The imager turns 360 degrees around the breast, snapping about 300 pictures in 10 seconds.

A software program analyses the digital data and produces a three-dimensional picture similar to that captured with an MRI.
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"The advantage of CT is that it's much higher resolution than MRI. The detail should be greater than anything else that we can do at this point," said Kopans.

The researchers are still in clinical trials, while the system awaits FDA approval. The start-up company, Koning Corporation in Rochester, New York has exclusive rights to marketing the imaging system.

Astronauts Struggle With Solar Array
Jean-Louis Santini, Associated Press
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Dec. 14, 2006 —The crews of the Discovery and the International Space Station grappled with a solar array that refused to fully retract, raising the possibility of an unscheduled fourth spacewalk.

For several tedious hours, astronauts painstakingly tried to fold up the six-year-old, 115-foot (35-meter) solar array on the ISS by remote control, but were unable to complete the job when the system jammed.

A refolding of the old array, which was used to generate electricity for the orbiting space station, is necessary to allow the new solar array to rotate to track the sun.
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"A map never goes back to the way you bought it, it just doesn't," said John Curry, flight director for the space station.

Astronauts on the space shuttle had three spacewalks scheduled during their 12-day mission that began Saturday. The first on Tuesday was used to attach a two-tonne truss segment on the ISS.

The second and third spacewalks, on Thursday and Saturday, will be used to rewire the ISS so a solar array installed in September can be switched on to provide additional power to the station.

NASA said a fourth spacewalk may be needed to manually fold the old array but that would not take place before the third scheduled spacewalk is over on Saturday.

It was unclear whether the additional spacewalk, should it be needed, would prolong the Discovery mission beyond its scheduled return date of Dec. 21.

The new array installed during the September mission of the space shuttle Atlantis will double the ISS's power supply.

It was expected to be activated on Wednesday after the older array had been retracted. The older array will eventually be moved to another spot on the ISS.

Although it has not been retracted to its ideal position, NASA said the older array has been foreshortened enough to allow the highly complex rewiring work to proceed as scheduled during the spacewalks on Thursday and Saturday.

Discovery mission specialist Robert Curbeam and Sweden's first astronaut Christer Fuglesang, of the European Space Agency, who performed the first space walk, were assigned Thursday's task.

The astronauts will reconfigure and rewire the electricity and climate control of the US-made portion of the ISS from its present, temporary set-up.

During the work, power to half of the ISS will be switched off.

On Saturday Curbeam and mission specialist Sunita Williams will install cameras outside the ISS expected to greatly facilitate future construction work.

A minor hiccup in the Discovery construction mission, apparently without serious consequences, happened during the first six-hour space walk, when Fuglesang lost an extender on a tool and it floated off in space.


The girder-like ISS is being assembled piece by piece. Construction resumed in September with the Atlantis mission, after a three-year hiatus following the 2003 Columbia disaster.

The Discovery mission is part of 14 shuttle flights NASA has planned over the next four years to finish the ISS by 2010, when the shuttle fleet, down to three vehicles, is to be retired.

Discovery blasted off late Saturday from Cape Canaveral, Florida — the first nighttime liftoff in four years. It docked on the station Monday and is to remain there eight days.
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National Aeronautics and Space Administration engineers said two preliminary inspections carried out after takeoff and shortly before Discovery docked with the ISS found no damage to the Discovery's heat shield during launch.

Such inspections on the shuttles have become routine since the Columbia tragedy.

Columbia's heat shield was pierced by foam insulation that peeled off its fuel tank during liftoff, causing the shuttle to disintegrate during its return to Earth in February 1, 2003, killing all seven astronauts on board.

Fur Color Linked to Dog Personality
Jennifer Viegas, Discovery News
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Dec. 13, 2006 — The color of a dog's fur may seem to be just a whim of nature and genetics that reveals little about the dog. But a new study claims that coat color for at least one breed, the English cocker spaniel, reflects a pooch's personality.

Prior research has suggested that fur color is also linked to behavior in labrador retrievers, while the type of fur — in this case, wiry or long — may indicate temperament in miniature dachshunds. Wiry-haired mini dachshunds are often more feisty than their mellower, long-haired cousins.
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The latest study, recently published in Applied Animal Behavior Science, determined that golden/red English cocker spaniels exhibit the most dominant and aggressive behavior. Black dogs in this breed were found to be the second most aggressive, while particolor (white with patches of color) were discovered to be more mild-mannered.

In labrador retrievers, the color rank from most to least aggressive was determined to be yellow, black and chocolate.

The behavior-fur color connection is likely due to related genetic coding that takes place during the pup's earliest life stages, according to lead author Joaqun Prez-Guisado.

"Maybe the link (to coat color) is due to the fact that the ectoderm (one of the three primary germ cell layers) is where the skin and central nervous system originate in the embryo," he told Discovery News.

Prez-Guisado, a researcher in the Department of Medicine and Animal Surgery at the University of Cordoba, Spain, and his colleagues measured levels of dominance and aggression in 51 seven-week-old English cocker spaniel puppies that were either full siblings or half siblings.

The tests looked at how quickly a person could capture a puppy's attention, how well puppies followed the individual, how the dogs behaved while restrained, how they exerted their social dominance and what they did when they were lifted off the floor.

In many cases, the golden-colored dogs resisted human contact and even tried to bite the tester, while the particolor pups often wagged their tails and seemed to enjoy the attention.

While genes control coat color and appear to predispose behavior in certain dogs, Prez-Guisado said that how dogs are raised plays the biggest role in behavior. He determined that environmental factors account for 80 percent of dominant, aggressive personalities while genes only influence 20 percent of dogs' demeanors.

"It is very important to give the dog an optimum and suitable environment in order to have a dog with a low dominance aggressive behavior level," he said. "For that reason, owners are primarily responsible for this undesirable dog behavior."

Fur Color Linked to Dog Personality
Jennifer Viegas, Discovery News
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Canine behaviorist and trainer Wendy Volhard and professional breeder Carolyn Sisson, who is president of the English Cocker Spaniel Club of San Diego, California, both told Discovery News they're not surprised by the findings. They said that coat color's link with behavior has been "a well-known, old wives' tale" for years.

Although they both think there is "some truth to the recent findings," Sisson believes a dog's genetic lineage, going back many generations, is a better indicator of temperament than color.
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Sisson explained that there are 29 recognized different coat colors for English cocker spaniels, and combinations other than golds mating with golds can result in a golden dog.

"It's the line breeding out of puppy mills in England that probably resulted in the dominant traits," Sisson said.

She added, "The very best and worst of my dogs have been spaniels. They seem to cover every behavioral extreme."

Prez-Guisado and his colleagues next plan to study the English springer spaniel and English cocker spaniel genomes to pinpoint common genes associated with so-called dog "rage" and coloration.

lying Mammals Lived With Dinos
Malcolm Ritter, Associated Press
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Dec. 13, 2006 — A new fossil discovery from China shows that a tiny squirrel-like creature glided through the air during the age of dinosaurs, more than 75 million years earlier than scientists had documented that ability in a mammal.

The creature might have even beaten birds into the air.

Like today's flying squirrels, it stretched a furry membrane between its limbs to provide an airfoil for gliding after it jumped from a tree. But it's not related to anything living today.
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Scientists don't know exactly when the animal lived. Its remains could be anywhere from 130 million to 164 million years old, said Jin Meng of the American Museum of Natural History. He and colleagues from Beijing report the discovery in Thursday's issue of the journal Nature.

So it's clearly older than the 51 million-year-old bat that used to be the oldest evidence of flying or gliding in a mammal. And it has a chance of preceding the earliest known bird, Archaeopteryx, which flew about 150 million years ago.

It is much younger than flying reptiles called pterosaurs, which are dated from 230 million years ago.

Still, added to a recent find in the same locale in northeastern China that revealed a semi-aquatic creature, the discovery shows that early mammals were a lot more varied than the land-loving creatures scientists have traditionally envisioned, Meng said.

He and colleagues dubbed the animal Volaticotherium antiquus, which is Latin and Greek for "ancient flying (or winged) beast."

   

They believe it was nocturnal, like other mammals of the time were thought to be, and like gliding mammals are today. It was the size of a flying squirrel or a bat — less than three ounces. Its stiff tail might have been longer than the trunk of its body.

The find includes not only bones, but also impressions left in rock that reveal the furry membrane the creature used for gliding. Its teeth show it ate mostly insects, researchers said. But it probably couldn't hunt insects while gliding because it was too clumsy a flier and couldn't stay airborne long enough, researchers said.

So why glide? It's hard to draw conclusions for this creature specifically, Meng said, but in general, scientists think that gliding is an energy-saving way to get from tree to tree, compared to repeatedly climbing up and down trunks. Gliding probably increased the foraging range of the creature and maybe helped it escape predators in the trees, he said.
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Larry Heaney, curator of mammals at the Field Museum in Chicago who has long studied gliding mammals, said the new creature "has taken the first step" toward powered flight like a bat exhibits.

But from its anatomy, "I would say this animal probably was not very far along the path to true flight," Heaney said. "It was not on the road to the kinds of modifications we see in bats that allow them to actually fly."

Meng said it's not clear whether descendants of the creature gained the ability to fly.