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Thursday, May 29, 2008

Strange Ring Found Circling Dead Star

ghostly ring extending seven light-years across around the corpse of a massive star This image shows a ghostly ring extending seven light-years across around the corpse of a massive star. Image credit: NASA/JPL-Caltech
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Pasadena, Calif. -- NASA's Spitzer Space Telescope has found a bizarre ring of material around the magnetic remains of a star that blasted to smithereens.

The stellar corpse, called SGR 1900+14, belongs to a class of objects known as magnetars. These are the cores of massive stars that blew up in supernova explosions, but unlike other dead stars, they slowly pulsate with X-rays and have tremendously strong magnetic fields.

"The universe is a big place and weird things can happen," said Stefanie Wachter of NASA's Spitzer Science Center at the California Institute of Technology, Pasadena, who found the ring serendipitously. "I was flipping through archived Spitzer data of the object, and that's when I noticed it was surrounded by a ring we'd never seen before." Wachter is lead author of a paper about the findings in this week's Nature. You can see the ring at http://www.nasa.gov/mission_pages/spitzer/multimedia/20080528.html .

Wachter and her colleagues think that the ring, which is unlike anything ever seen before, formed in 1998 when the magnetar erupted in a giant flare. They believe the crusty surface of the magnetar cracked, sending out a flare, or blast of energy, that excavated a nearby cloud of dust, leaving an outer, dusty ring. This ring is oblong, with dimensions of about seven by three light-years. It appears to be flat, or two-dimensional, but the scientists said they can't rule out the possibility of a three-dimensional shell.

"It's as if the magnetar became a huge flaming torch and obliterated the dust around it, creating a massive cavity," said Chryssa Kouveliotou, senior astrophysicist at NASA's Marshall Space Flight Center, Huntsville, Ala., and a co-author of the paper. "Then the stars nearby lit up a ring of fire around the dead star, marking it for eternity."

The discovery could help scientists figure out if a star's mass influences whether it becomes a magnetar when it dies. Though scientists know that stars above a certain mass will "go supernova," they do not know if mass plays a role in determining whether the star becomes a magnetar or a run-of-the-mill dead star. According to the science team, the ring demonstrates that SGR 1900+14 belongs to a nearby cluster of young, massive stars. By studying the masses of these nearby stars, the scientists might learn the approximate mass of the original star that exploded and became SGR 1900+14.

"The ring has to be lit up by something, otherwise Spitzer wouldn't have seen it," said Enrico Ramirez-Ruiz of the University of California, Santa Cruz. "The nearby massive stars are most likely what's heating the dust and lighting it up, and this means that the magnetar, which lies at the exact center of the ring, is associated with the massive star-forming region."

Rings and spheres are common in the universe. Young, hot stars blow bubbles in space, carving out dust into spherical shapes. When stars die in supernova explosions, their remains are blasted into space, forming short-lived beautiful orbs called supernova remnants. Rings can also form around exploded stars whose expanding shells of debris ram into pre-existing dust rings, causing the dust to glow, as is the case with the supernova remnant called 1987A.

But the ring around the magnetar SGR 1900+14 fits into none of these categories. For one thing, supernova remnants and the ring around 1987A cry out with X-rays and radio waves. The ring around SGR 1900+14 only glows at specific infrared wavelengths that Spitzer can see.

At first, the astronomers thought the ring must be what's called an infrared echo. These occur when an object sends out a blast wave that travels outward, heating up dust and causing it to glow with infrared light. But when they went back to observe SGR 1900+14 later, the ring didn't move outward as it should have if it were an infrared echo.

A closer analysis of the pictures later revealed that the ring is most likely a carved-out cavity in a dust cloud -- a phenomenon that must be somewhat rare in the universe since it had not been seen before. The scientists plan to look for more of these rings.

"This magnetar is still alive in many ways," said Ramirez-Ruiz. "It is interacting with its environment, making a big impact on the young star-forming region where it was born."

Other paper authors include V. Dwarkadas of the University of Chicago, Ill.; J. Granot of the University of Hertfordshire, England; S.K. Patel of the Optical Sciences Corporation, Huntsville, Ala.; and D. Figer of the Rochester Institute of Technology, N.Y. NASA's Jet Propulsion Laboratory, Pasadena, Calif., manages the Spitzer mission for NASA's Science Mission Directorate, Washington. Science operations are conducted at the Spitzer Science Center. Caltech manages JPL for NASA. Spitzer's infrared array camera, which made the observations, was built by NASA's Goddard Space Flight Center, Greenbelt, Md. Its principal investigator is Giovanni Fazio of the Harvard-Smithsonian Center for Astrophysics. For more information about Spitzer, visit http://www.spitzer.caltech.edu/spitzer and http://www.nasa.gov/spitzer .
Media contact: Whitney Clavin 818-354-4673
Jet Propulsion Laboratory, Pasadena, Calif.
whitney.b.clavin@jpl.nasa.gov

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Astronomy Picture of the Day

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

2008 May 29

A Fog Bow Over Ocean Beach
Credit & Copyright: Keith C. Langill (missionblvd.com)

Explanation: What is that white arch over the water? What is being seen is a fogbow, a reflection of sunlight by water drops similar to a rainbow but without the colors. The fog itself is not confined to an arch -- the fog is mostly transparent but relatively uniform. The fogbow shape is created by those drops with the best angle to divert sunlight to the observer. The fogbow's relative lack of colors are caused by the relatively smaller water drops. The drops active above are so small that the quantum mechanical wavelength of light becomes important and smears out colors that would be created by larger rainbow water drops acting like small prisms reflecting sunlight. The above striking image of a fogbow was taken last week with the Sun behind the photographer. The rocks in the foreground are part of Ocean Beach in California, USA.

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The starry-eyed visitor

In a scientific love story, the world's top telescope historian fulfills a lifelong dream to see the world's largest refracting telescope

Rolf Riekher, 86, a former German optical lens engineer, fulfilled a lifelong dream to see the University of Chicago's Yerkes Observatory 40" diameter telescope in Williams Bay, Wis., April 23, 2008. MORE PHOTOS>>> (Chicago Tribune photo by David Trotman-Wilkins / April 23, 2008)

WILLIAMS BAY, WIS.—Late one sunny afternoon in April, Kyle M. Cudworth, director of Yerkes Observatory complex, opened up the door leading into the main observatory.

Shuffling behind Cudworth, 86-year-old Rolf Riekher, a small, slightly stooped, white-haired man, smiled with unalloyed delight. His eyes darted around the circular room, a vast space—and then they fixed on the massive, dark metal pier at the room's center. Looking up, he saw it: a slender, gracefully canted 63-foot-long white tube.

Built in 1897, at the apex of the Victorian age, this mighty telescope was the international space station of its time. It remains the world's biggest refracting telescope.

It was an amalgam of the age's finest technologies—clockworks, electric motors, precision gears, cameras and perfectly ground lenses—exploring the universe more deeply than ever before. Still in use 111 years later, it remains awe-inspiring.

"I know it very well from pictures, but it is absolutely different to be here in its actual presence. It is incredibly impressive," said Riekher, the world's pre-eminent historian of telescopes.

Finally getting to see it fulfilled a lifelong dream.

What delayed the prominent telescope expert from seeing the important telescope was Riekher's unusual, isolated life and career in Germany under the Nazi and East German communist regimes.

In 1938, Riekher, at 16, left school and formal education behind in his hometown of Schwerin in Northern Germany. He apprenticed as a clerk in an optician's shop, where he learned the science of spectacles, binoculars and cameras that he sold.

Too sickly for military duty, at the end of World War II in 1945 he was still in Schwerin, a citizen of devastated communist East Germany. To survive, he built his own machines and began grinding spectacle lenses. He was so proficient that in 1951 the East German Academy of Science hired him as an optical engineer. For 36 years he led teams that won the world's first patents for transitional [no-line] bifocals, did early laser research and built Soviet satellite optics.

An amateur astronomer, as a labor of love Riekher wrote a history of telescopes, "Telescopes and Their Masters," published in 1957 in East Berlin. Never translated from German, copies of the book and its 1990 second edition eventually seeped outside East Germany, coming to be regarded as the best book on the subject ever written.

"It is the definitive volume on the subject. No one in the field of the history of astronomy could function without it," said Adler Planetarium technology historian Marvin Bolt, 45.

This year is the 400th anniversary of the invention of the telescope. The anniversary spurred Bolt and Skokie-born Michael Korey, 42, a museum conservator in Germany, to try to find a publisher for an English translation of "Telescopes and Their Masters." As part of that still-pending venture, they brought Riekher to Chicago.

That is how he, Bolt and Korey found themselves under Yerke's 90-foot domed observatory in April, getting the cook's tour of the place from Cudworth, a University of Chicago astronomer who still uses the telescope.

The place has the aura of a scene from a Jules Verne science fiction novel, a feeling reinforced when an aide to Cudworth climbed a stairway to the base of the dome to hit a button, and the dome viewing slit began to open with an unworldly creak. Below, at a control panel on the floor, Cudworth threw a switch and the dome itself chattered noisily as it revolved until the slit was in line with the telescope.

From its perch on the massive metal pier in the middle of the room, the telescope hung out of reach a good 25 feet above Cudworth and the others. The wooden floor they stood on, 75 feet across, is built like a doughnut around but not touching the pier.

Cudworth threw another switch and the entire 30,000-pound floor slowly rose until it was just 5 feet below the telescope eyepiece.

"It's still the biggest elevator in the world," Cudworth said of the floor. He reached for the telescope, easily pivoting the 12,000-pound tube into any position he wanted by hand, a show of remarkable 19th Century craftsmanship.

Long familiar with the telescope and its history, Riekher was transfixed, nonetheless.

"The technical construction of telescopes is what fascinates me," he said. "I always like to note how people tackled certain problems."

Two hours into the tour, Cudworth excused himself to go home for dinner, promising to return at 10 p.m. to assist Riekher in viewing the night sky with the telescope.

After Cudworth left, Riekher nimbly stepped through railings of a spiral stairway winding up one side of the pier and began climbing around.

"Don't you two follow me up here," Riekher admonished Korey and Bolt. "I've been on a lot of these things. ... You might get hurt."

He then spent an hour nimbly negotiating the tower.

Astronomers quit building big refracting telescopes once they reached the size of Yerkes', when they found they could more easily and cheaply build even bigger, more powerful reflecting telescopes using mirrors.

The Yerkes refractor continues to work perfectly, but its viewing in recent decades has been weakened by electric lights of surrounding towns.

The old historian didn't seem to mind. He saw, he said, what he came to see, "the culmination of a great era of technological development."

wmullen@tribune.com

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Astronomy Picture of the Day

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

2008 May 28

Dark Clouds of the Carina Nebula
Credit: NASA, ESA, N. Smith (U. California, Berkeley) et al., and The Hubble Heritage Team (STScI/AURA)

Explanation: What dark forms lurk in the mists of the Carina Nebula? These ominous figures are actually molecular clouds, knots of molecular gas and dust so thick they have become opaque. In comparison, however, these clouds are typically much less dense than Earth's atmosphere. Pictured above is part of the most detailed image of the Carina Nebula ever taken, a part where dark molecular clouds are particularly prominent. The entire Carina Nebula spans over 300 light years and lies about 7,500 light-years away in the constellation of Carina. NGC 3372, known as the Great Nebula in Carina, is home to massive stars and changing nebula. Eta Carinae, the most energetic star in the nebula, was one of the brightest stars in the sky in the 1830s, but then faded dramatically. Wide-field annotated and zoomable versions of the larger image composite are also available.

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Oldest vertebrate fish mother discovered

By Michael Perry

SYDNEY (Reuters) - Australian scientists unveiled on Thursday the fossilized remains of the oldest vertebrate mother ever discovered, a 375-million-year-old placoderm fish with embryo and umbilical cord attached.

The fossil, found in the Gogo area of northwest Australia, is proof that an ancient species had advanced reproductive biology, comparable to modern sharks and rays, said John Long, head of sciences at the Museum of Victoria in Melbourne.

"It is not only the first time ever that a fossil embryo has been found with an umbilical cord, but it is also the oldest known example of any creature giving birth to live young," Long told Reuters.

The placoderms, often referred to as "the dinosaurs of the seas", were the rulers of the world's lakes and seas for almost 70 million years. Most species of the armored fish were quite small but some reached over 20 feet in length.

Placoderms are from the late Devonian period when land animals evolved from fish.

"This discovery changes our understanding of the evolution of vertebrates," Long said.

"It will make us rethink the early evolution of vertebrate in terms of how reproduction has driven evolutionary events."

Long said little was known about how reproductive changes from spawning eggs to internal fertilization affected the evolution species.

The scientists have published their finding in the latest Nature journal (http://www.nature.com/nature).

"The new specimen, remarkably preserved in three dimensions, contains a single, intra-uterine embryo connected by a permineralized umbilical cord. An amorphous crystalline mass near the umbilical cord possibly represents the recrystallized yolk sac," wrote the scientists.

"Our new example extends the definite record of vertebrate viviparity (giving birth to live young) back by some 200 million years," the scientists wrote in the journal.

They said the new discovery points to internal fertilization and viviparity in vertebrates as originating earliest within placoderms.

The Australian scientists have named their 25-cm fossil, Materpiscis attenboroughi, in honor of Sir David Attenborough, who first drew attention to the Gogo fish sites in the 1979 series Life on Earth.

"The existence of the embryo and umbilical cord within the specimen provides scientists with the first ever example of internal fertilization, sex, confirming that some placoderms had remarkably advanced reproductive biology," said Long.

"This is the first bit of evidence on how a complete extinct class of animals may have reproduced."

The fossil will go on display in the foyer of Melbourne Museum from May 29.

(Editing by Valerie Lee)

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Diary from the eye of the storm

For the next week, the BBC's Simon Hancock will be chasing storms through Tornado Alley, an area of high tornado activity that runs through the centre of the US. He has joined a professional team which hunts out tornadoes using hi-tech gadgets.

DAY THREE: THE SOUND AND THE FURY

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Driving through the eye of a storm

It is not often a seasoned storm chaser will admit to being afraid, but today our tour director Brian Barnes did just that during our search for the all-important tornado.

The experience happened just inside the Texan border as we drove right through the middle of a severe storm.

Hail from tornado alley
Hail battered the van

Rain and hail battered the van, while visibility was reduced to just a couple of feet, with our driver Paul often having to turn into the wind in order to keep the vehicle on the road.

Brian may have been nervous, but he didn't show it. It was only after dinner later that evening that we realised how close we had come to being tipped over as a result of the cyclonic activity that you get in the middle of a severe thunderstorm.

As one of the tour quite rightly commented: "Ignorance is bliss!".

Earlier, we had come very close to seeing our first twister, with weather conditions almost perfect, until another storm cell bowled into the one we were watching and ruined the moment for us - Brian explained what was happening in the video below.

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Brian Barnes explains how a tornado could be about to form

Unfortunately, despite being subjected to the might of the storm, we were unable to catch a glimpse of that all elusive tornado.

Sunset in tornado alley
Sunsets are spectacular in Tornado Alley

We did however see some hail - while it was not quite of the calibre of the baseball-sized hail that can occur during storm season, it would still be pretty painful if it landed on your head!

One curious feature of Tornado Alley is that while the sky on one side of you may be sunny and clear, the other side could contain a cloud straight from a Stephen King horror novel.

This was perfectly illustrated at the end of the day as we stopped to survey the storm damage in an Oklahoma field that had been hit by a twister just minutes before we arrived.

Facing the van was an amazing red sunset, while behind was one of the most intense lightning storms I have ever seen.

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Storm lights Oklahoma sky

Three days down and no tornado yet but we do feel we are getting closer.

Maybe all we need is a little luck. Fingers crossed!

DAY TWO: A TERRIBLE BEAUTY

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Kit for storm chasing

Note to self - if you are going storm chasing it might be a wise idea to bring a rain coat!

Today was the first real day of our mission to capture a tornado.

In an effort to travel in the tour van with as little kit as possible we took only the bare essentials to ensure we wouldn't leave our fellow chasers trying to avoid sitting beside us.

Storm chasing van
So far, tornadoes has proven elusive, but the team have witnessed beautiful sunsets

We headed off at noon and tour director Brian informed us that we would hopefully get some action later in the day around the Kansas area.

Part of the fascination with tornado chasing is the fact that they can be small, isolated events in a big area.

And as with a safari, you need to know what signs to look for - they need several meteorological factors in place to feed their energy-loving needs.

Knowing how they work and having the equipment to spot these factors is vital. Before we left, Brian gave us a tour of his arsenal.

Beautiful sunsets, but no tornado

So we were off, and we perhaps naively expected to see something immediately.

Brian hovered over his console the whole time, checking the data and listening to the localised storm warnings on his ham radio, which spoke of golf ball- and baseball-sized hail.

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The team listened to warnings over the radio

After several hours of driving, we noticed a change in Brian's demeanour and an intense look of concentration on his face as he repeatedly scanned the skies - as well as his PCs.

He went very quiet.

We were in between two severe storms, and he thought there was a good chance of tornado development and didn't want to be taken by surprise.

He explained later that he was continually calculating escape routes in case the storm turned upon us. In the excitement of the moment it's easy to forget what you're dealing with.

Another reminder of our predicament came as our storm tracking took us through Greensburg, a town which was levelled by a ferocious tornado just last year.

Greenberg after tornado
Greensberg suffered enormous damage after being hit by tornado last year.

In the eerie light of the storm it looked like Armageddon.

But by the end of the day, while we'd seen amazing lightning formations, spectacular skies and a beautiful sunset - a tornado had proven elusive.

Tomorrow we depart early from our motel in Wichita to pick up the trail again. Here's to another wet and windy day!

DAY ONE: EXPECTATIONS AND NAGGING DOUBTS

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BBC weatherman Daniel Corbett explains how tornadoes form

My colleague Alan and I flew into Dallas. As we picked up our rental car a video of an enormous tornado ripping up the land was playing on the news.

This surely augured well for our storm chasing trip - though Alan pointed out that celebrating this with the rental car company might not be the best idea.

This year's tornado season in Tornado Alley has been much more active than usual, some say because of La Nina conditions.

Almost every day in this region there have been countless stories of destruction, near misses and lucky escapes caused by these powerful meteorological phenomena.

We're hoping to catch a bit of this action.

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This amateur footage shows that the tornado season is well under way (William Hark)

We arrive in Oklahoma City and meet up with our tour group.

The tour is being run by professional tornado chasers Violent Skies under the guidance of Brian Barnes. Brian's father was a storm chaser and now he works with a mix of hi-tech gadgetry and instinct built up over the years.

At our hotel base camp, Brian took us through some of the meteorological features that he uses to figure out just where the tornado might be.

Storm chasing briefing
The Violent Skies team explained the dangers of storm chasing

He explained that he gets up every hour during the night to check on just what the weather is up to, and warned us to be ready to leave at a moment's notice if he spotted a window of opportunity.

His briefing also left us in no doubt about the potential danger of storm chasing, a point echoed when we went to the bar later that night and again found wall-to-wall coverage of tornadoes on TV.

We also met some of the locals who couldn't believe that we were coming to chase tornadoes while they had spent their entire lives trying to get away from them.

I think it's fair to say they thought we were slightly odd in this respect.

While their comments and the amazing footage on the local news gave us hope that we might get to see the power of the storm, it also made us think twice about just what we had let ourselves in for.

Tomorrow the chase begins.

Animated guide: Tornadoes

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Women Have a Better Memory for Faces and Words

Do women remember better than men do? Research shows that females may have an advantage when it comes to episodic memory, a type of long-term memory based on personal experiences. A Swedish team of psychologists showed, for example, that women are better on average than men at remembering faces, particularly female faces. These findings may have an evolutionary explanation that is rooted in female-female competition, says David C. Geary, a psychologist at the University of Missouri–Columbia who was not involved with the study. “Women certainly fought and continue to fight over the best guys ... those with good genes and resources to invest in kids,” Geary says. Remembering details of personal experiences is important for monitoring and maneuvering relationships, including disrupting the social and romantic ties of other women who are competitors, he says. Previous studies have shown that women also have a superior memory for verbal information, which they may use to dissect a person’s underlying motives or intentions—a skill that, according to Geary, “seems to elude many men.”

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What Your Eyes Say About Your Mood

When compared with a neutral, unmodified face, left, a face with elevated eyebrows, center, was perceived as sad and tired. A face with lower eyebrows, right, was more often seen as angry or disgusted.

Has anyone ever told you that you looked sad or tired when you weren’t? If the problem isn’t your mood, it might be your face, according to a study in the medical journal Plastic and Reconstructive Surgery.

Yale University researchers set out to determine how facial features like eyebrow shape, eyelids and wrinkles affect facial expressions. They took a photo of a woman’s eyes and digitally altered it to change the eyebrow or lid shape or add wrinkles. After producing 16 different versions of the same face, they asked 20 study participants to rate, on a scale of 0 to 5, the presence of seven expressions or emotions: tiredness, happiness, surprise, anger, sadness, disgust and fear.

What was surprising about the study is that many of the pictures that mimicked various plastic surgery procedures, such as eyelid surgery or brow lifts, actually generated worse scores, with study participants rating those faces as looking angry or tired.

For instance, drooping of the upper eyelid was the biggest indicator of tiredness, but a picture that simulated a type of eyelid surgery — involving the removal of excess skin from the upper eyelid — made the woman look even more tired and sad, the study participants reported. Raising the upper eyelids produced an increase in the perception of surprise and fear.

“A significant number of plastic surgery patients opt for eyelid surgery, forehead lifts and face-lifts not only for rejuvenative reasons, but to change an unattractive facial expression as well,” said Dr. John A. Persing, one of the study authors. “Our findings indicate that moderation is best when removing excess skin in the upper eyelid. You do not want to create an overdone look that actually makes you look more tired.”

Eyebrows made a big difference in how people perceived the mood of the woman in the picture. When the brows were lowered or slanted toward the nose, or when forehead wrinkles were added, ratings of anger and disgust increased.

Also, raising the outer corner of the eyebrows produced an increase in the perception of surprise. Raising the inner corner of the eyebrows away from the nose was perceived as a sad facial expression.

According to the American Society of Plastic Surgeons, more than 241,000 eyelid surgeries, 43,000 forehead lifts and 118,400 face-lifts were performed in 2007. But the study shows that people contemplating eye surgery should talk to their doctor about how a procedure might affect their facial expressions. And some people might want to think twice about eliminating some sets of wrinkles. One digitally-altered picture added crows’ feet — tiny wrinkles around the eyes — and received high ratings for “happiness.'’

“The eyes and their related structures nonverbally communicate a wide range of expressions that are universal to all people,” Dr. Persing said. “Therefore facial expression should be a factor in how patients and their plastic surgeons select various rejuvenation procedures. As our findings show, even the slightest modification can elicit profound changes in how others perceive us.”

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Giant Flying Reptiles Preferred To Walk


A group of Quetzalcoatlus, another type of giant azhdarchid, strolling around a fern prairie eating baby dinosaurs for lunch. (Credit: Mark Witton)

New research into gigantic flying reptiles has found that they weren't all gull-like predators grabbing fish from the water but that some were strongly adapted for life on the ground.

Pterosaurs lived during the age of dinosaurs 230 to 65 million years ago. A new study by researchers at the University of Portsmouth on one particular type of pterosaur, the azhdarchids, claims they were more likely to stalk animals on foot than to fly.

Until now virtually all pterosaurs have been imagined by palaeontologists to have lived like modern seabirds: as gull- or pelican-like predators that flew over lakes and oceans, grabbing fish from the water. But a study of azhdarchid anatomy, footprints and the distribution of their fossils by Mark Witton and Dr Darren Naish shows that this stereotype does not apply to all flying reptiles and some were strongly adapted for terrestrial life.

Azhdarchids were probably better than any other ptersosaurs at walking because they had long limbs and skulls well suited for picking up small animals and other food from the ground.

Azhdarchids, named after the Uzbek word for 'dragon', were gigantic toothless pterosaurs. Azhdarchids include the largest of all pterosaurs: some had wingspans exceeding 10 metres and the biggest ones were as tall as a giraffe.

Dr Naish said: "Azhdarchids first became reasonably well known in the 1970s but how they lived has been the subject of much debate. Originally described as vulture-like scavengers, they were later suggested to be mud-probers (sticking their long bills into the ground in search of prey), and later still suggested to make a living by flying over the water's surface, grabbing fish.

"Other lifestyles have been suggested too. These lifestyles all seem radically divergent so Mark and I sat down and carefully examined the evidence and we argue that azhdarchids were specialised terrestrial stalkers. All the details of their anatomy, and the environment their fossils are found in, show that they made their living by walking around, reaching down to grab and pick up animals and other prey."

Animals like azhdarchids no longer exist but the closest analogues in the modern world are large ground-feeding birds like ground-hornbills and storks.

The researchers studied fossils in London, Portsmouth and Germany and compared the anatomy of azhdarchid with those of modern animals. This showed that azhdarchids were strikingly different from mud-probers and animals that grab prey from the water's surface while in flight.

Dr Naish said: "We also worked out the range of motion possible in the azhdarchid neck: this bizarrely stiff neck has previously been a problem for other ideas about azhdarchid lifestyle, but it fits with our model as all a terrestrial stalker needs to do its raise and lower its bill tip to the ground."

Other aspects of azhdarchid anatomy, such as their relatively small padded feet and long but weak jaws often pose problems in other proposed lifestyles but fit perfectly with the terrestrial stalker hypothesis. Mr Witton said: "The small feet of azhdarchids were no good for wading around lake margins or swimming should they land on water but are excellent for strutting around on land. As for what azhdarchids would eat, they'd have snapped up bite-size animals or even bits of fruit. But if your skull is over two metres in length then bite-size includes everything up to a dinosaur the size of a fox."

The researchers found that over 50 percent of azhdarchid fossils come from sediments that were laid down inland. Significantly, the only articulated azhdarchid fossils we have come from these inland sediments.

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Monkey's brain controls robot arm


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The monkeys were able to use the robot arm to feed themselves treats

Monkeys have been able to control robotic limbs using only their thoughts, scientists report.

The animals were able to feed themselves using prosthetic arms, which were controlled by brain activity.

Small probes, the width of a human hair, were inserted into the monkeys' primary motor cortex - the region of the brain that controls movement.

Writing in Nature journal, the authors said their work could eventually help amputees and people who are paralysed.

Lead researcher Dr Andrew Schwartz, who is based at the University of Pittsburgh School of Medicine, said: "We are beginning to understand how the brain works using brain-machine interface technology.

"The more we understand about the brain, the better we'll be able to treat a wide range of brain disorders, everything from Parkinson's disease and paralysis to, eventually, Alzheimer's disease and perhaps even mental illness."

natural movement

With the probes inserted into the monkeys' motor cortices, computer software was used to interpret the brain's electrical impulses and translate them into movement through the robotic arm.

This arm was jointed like a human arm and possessed a "gripper" that mimics a hand.

we've demonstrated a higher level of precision, skill and learning.
Dr Andrew Schwartz

After some training, two monkeys - who had had their own arms restrained - were able to use the prosthetic limbs to feed themselves with marshmallows and chunks of fruit.

The researchers said that the movements were fluid and natural.

The monkeys were able to use their brains to continuously change the speed and direction of the arm and the gripper, suggesting that the monkeys had come to regard the robotic arm as a part of their own bodies.

The success rate of the experiment was 61%.

Dr Schwarz said: "In our research, we've demonstrated a higher level of precision, skill and learning.

"The monkey learns by first observing the movement, which activates its brain cells as if it was doing it. It's a lot like sports training, where trainers have athletes first imagine that they are performing the movements they desire."

Complex brain

He said the research could eventually benefit the development of prosthetic limbs for people with spinal cord injuries or for amputees.

He said: "Our immediate goal is to make a prosthetic device for people with total paralysis."

"Ultimately, our goal is to better understand brain complexity."

Commenting on the paper, Professor Paul M Matthew from the Hammersmith Hospital, said: "The challenge of interfacing the billions of nerve cells in the brain that control the full range of limb movements directly with a mechanical prosthesis has seemed impossibly difficult.

"However, this important paper confirms that the brain controls movement just by planning where to go, rather than by directing individual muscles how to make the limb get there.

"The study shows that fewer than 100 tiny electrical signals generated in the specialised area known as the 'motor cortex' can command even complex arm and hand movements.

"This moves the day when patients disabled after spinal cord injuries or amputations can use brain-controlled bionic limbs from the realm of science fiction towards science fact."

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Tornado warnings: Too much of a good thing?

Unbeknownst to you, an F5 tornado -- the kind that can obliterate a house in a heartbeat -- is barreling directly toward yours: Would you prefer 60 seconds warning or 20 minutes?

Silly question, you say? Yet research by a pair of Texas economists suggests that your choice may not matter in survival terms (that you'd have 19 minutes more to worry with option two is indisputable). In fact, the study raises the question of whether that extra time might actually do more harm than good.

But they're economists.

More surprisingly, the chief technology officer for the country's most extensive severe weather warning network says he would "bet there is some truth to their study" -- up to a point, and with funnel cloud-sized caveats that we'll get to in a moment.

The discussion began last week with this headline -- Early Tornado Warnings Not Always Helpful -- that appeared on the Web site LiveScience.

The researchers analyzed data from more than 18,000 tornadoes in the United States between 1986 and 2002. Overall, they found that early warning is very helpful: On average it reduced expected injuries by about 32 percent.

But when the researchers examined data from the most severe cases - the 300 out of 18,000 tornadoes in which people died - the effects of advanced warning were less clear. Overall, when people were notified of a tornado up to about 15 minutes ahead of time, deaths decreased. However, lead times greater than 15 minutes seemed to increase fatalities compared with no warning.

What could possibly account for such a counter-intuitive outcome? The researchers acknowledge that their data is insufficient for firm conclusions, but here's what they suspect:

"The concern is that longer lead times would encourage dangerous behavior," said Kevin Simmons, an economist at Austin College in Texas. "There is anecdotal evidence that came out of the tornadoes in Oklahoma and Missouri last week. Out of the 23 fatalities, eight were people in cars. I don't know if those people were trying to outrun the storm, or if they just happened to be in their cars."

Being from Massachusetts, where tornadoes are rare, I can claim little first-hand knowledge of such situations (aside from that vacation scare in Minnesota where the family watched on TV as a tornado skittered by about a half-town away from our rental.)

But I know a guy who knows: Chris Sloop, CTO at Weatherbug, which operates a network of more than 8,000 tracking stations and 1,000 cameras in schools, public safety buildings and TV stations. I made Sloop's acquaintance in 2005 when he accused me of callous disregard for the health and well being of my fellow man after I wrote what struck me then as a rather sympathetic column about his company being at Interop. Since that dustup, we've become e-mail buddies.

Here's some of what Sloop had to say about the economists' research:

I bet there is some truth to their study. When people don't know what to do in a dangerous situation, many times they do the wrong thing.

I am surprised the authors didn't take that approach. It is almost like they are saying that advance warning is a bad thing, when in reality it is a GREAT thing; it's just that people are not well educated enough to know how to respond. Of course, in cases like the most severe tornados, there may not be much you can even do that will save your life.

Another factor to consider here is that technology has changed dramatically since the era of the data sample used by the economists: 1986 to 2002.

People have a cell phone with them now wherever they go. The alerts that people get now are very localized and direct. So, there is much less worry about the crying wolf syndrome where people just ignore warnings ... and with our system, people can be alerted to just knowing that severe weather conditions are heading their way. ... The key though, is education and preparation. You need to know exactly what you are going to do when faced with a dangerous situation.

Work and recreational habits have changed as well, he notes.

The final thing I would like to point out is that all of these articles always talk about NOAA Weather Radio and television/radio like they are the only ways to get weather warnings. Who watches TV any more? People are on computers more than TV; I know I am and that is why products such as WeatherBug Desktop or WeatherBug Alert are very important. Not to mention all the cell phone/SMS capabilities.

Coincidentally, as I started to write this post, I received an alert about potentially damaging thunderstorms with marble-sized hail moving through my area. No, it wasn't from TV, radio or Weatherbug, rather it came via old-fashioned e-mail from a friend who for years has provided the service as a hobby. It works ... but like I said earlier, we don't get the killer storms in these parts very often.

In the event our luck does run out, please put me down for as much warning as possible.

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Top 10 Ways to NOT Screw the Earth at Work

Single-sided printers are a major eco-office complaint.
Single-sided printers are a major eco-office complaint.
Photo: George Doyle / Getty Images

Sure, work might be the most boring part of your life — perhaps you routinely count the seconds until each workday is over and dread coming in the following day. But so long as you're there, why not do your best to not screw up the environment?

Here are 10 ways anyone can get started:

10. Use energy-efficient lighting

Replace incandescent light bulbs with compact fluorescent light (CFL) or light emitting diode (LED) bulbs. Both CFLs and LEDs give off less heat than incandescents, plus they last longer. Even Fidel has made sure every Cuban office is using more efficient lights. If you haven't already, it's time to make the switch!

9. Get rid of water bottles

We've known about it for years, but never done a thing. Millions of plastic water bottles are being thrown away daily, and removing them from the office will help! Try using tap water, refilling old bottles, or even buying a water purification device. You can also purchase reusable beverage containers such as Nalgene (soon to be bisphenol A free) or Sigg.

8. Advocate your company's switch to renewable energy sources

Over 70 percent of electricity in the United States is generated through the use of fossil fuels such as coal, oil and natural gas. Try being the voice that gets your company to switch to cleaner, renewable sources — talk to your boss, start a petition or, if need be, refuse to wear clothing at work until your company gets its act together.

You might lose your job in the process, but at least you'll make your point. For a practical guide on switching to green energy, check out the World Resources Institute's "Switching to Green: A renewable energy guide for office and retail companies."

7. Join a carpool

The average automobile burns over 12 liters of gasoline in just one hour. Whether you're going to the same office, or just the same neighborhood, carpooling makes a heck of a lot of sense. It's not only easy on the wallet (particularly in light of current insane gas prices), but will reduce harmful CO2 and fossil fuel emissions. Sites like erideshare.com are cool if you're looking for potential carpool companions.

6. Power off your computer

Instead of putting your computer in sleep mode when you leave for an extended period of time, go ahead and shut the puppy off. Believe it or not, powering off completely can save up to 10 times the energy. And if you want to be a hero (and potentially piss of your co-workers), make sure their computers are also turned off after they've gone home for the evening. A word to the wise, however: first make sure everything is saved.

5. Use a laptop

On average, a laptop uses 10% less energy than a standard PC. Plus, if you're accustomed to spending a long time in the bathroom (after lunch, for example) you can multitask by bringing in your laptop — just be sure you don't drop it in the toilet.

4. Keep a keg under your desk

Not sure how it helps the environment, but it sure would make work a lot more fun!

3. Recharge your batteries

Offices use tons of batteries to power things like calculators and hand-held massage devices (at least my office does). When possible, buy rechargeable batteries — so they can be used time and time again and ultimately, create less waste. According to rechargeable battery makers Uniross, rechargeable batteries have 32 times less impact on the environment and use less than 1/23rd the natural resources of their disposable counterparts.

2. Turn off the AC and wear lighter-weight fabrics

Although the thermostat is usually governed by committee, turning off the AC is a quick and easy way to reduce your carbon footprint in the office. If your co-workers aren't happy to accommodate by wearing lighter clothing, you can either a) insulate heat by drawing blinds and curtains (roughly 40% of unwanted heat comes through windows) or b) lay an old-fashioned guilt trip on them (e.g., "You're single-handedly killing Mother Nature, Sally! How do you sleep at night?!")

1. Use paper wisely

This is the big one. Start printing documents double-sided, save scrap paper to jot notes on, and of course, recycle whenever possible. On the more novel side of things, those offices that still use paper time cards (a huge waste of paper!) should consider going electronic with a company like T-sheets. As a general rule of thumb, if you can move paper correspondence online, then go for it.

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Can the ecohackers save us?

Many scientists now believe the Earth can be altered to tackle global warming. But are these geoengineers being overly optimistic? Danny Bradbury investigates

Pinatubo erupted on June 17, 1991. Photograph: Alberto Garcia/Corbis

It sounds like something from B-movie lore. Scientists working to avert global catastrophe invent a terrible technical instrument that could affect the fundamental way that the planet operates. The question is not whether they should use it, but whether they have a choice. In both academic and privately funded laboratories, such techniques are being considered, mostly in response to global warming. Geoengineering, or "ecohacking" - using science to change the environment on a vast scale - could become a reality faster than you think.

There are roughly 385 parts per million (ppm) of carbon in the atmosphere today, and that's making scientists already concerned about global warming unhappy. "I think it's a good goal to not go over 450ppm," says Alan Robock, a professor in the department of environmental sciences at Rutgers University. Many in his field consider that figure to be a tipping point, when global warming could run out of control. "The solution is mitigation," he warns.

But how to mitigate? Paul Crutzen doesn't think we're moving fast enough with reductions in carbon emissions. The professor emeritus at Utrecht University's Institute for Marine and Atmospheric Sciences became one of the most famous geoengineering advocates for his idea of copying the Pinatubo volcano.

Its 1991 eruption sent 10m tonnes of sulphur (which became sulphur dioxide) into the atmosphere, reducing the global temperature by 0.5C the next year. Crutzen suggested a project to produce a similar effect, using balloons or artillery shells to put 1.9m tonnes of sulphur into the atmosphere to cool the Earth.

He wasn't the first would-be ecohacker. As far back as the 1970s, Russian climatologist Mikhail Budyko suggested putting reflective aerosols in the atmosphere. "And the first time that a US president was informed that there might be a global warming problem from carbon dioxide was in 1965," says Ken Caldeira, a scientist at the Carnegie Institution's department of global ecology. "President Johnson's advisors gave him a report that suggested we might put reflective materials across the surface of the ocean." The idea was that these would reflect large amounts of sunlight back into space and mitigate the effects of global warming.

Even in the early 19th century, US meteorologist James Espy advocated burning huge areas of forest in the hope of making rain by affecting the thermal dynamics of the atmosphere, says meterological historian and professor of science, technology, and society at Colby College James R Fleming.

When leading US meterologist Harry Wexler predicted ecohacking in a 1962 lecture, the first weather satellite had been up for three years. "He pointed out that any intervention with the Earth's heat budget could cause a change in the downstream flow and the climactic systems and weather patterns," says Fleming. "He gave serious lectures about the possible inadvertent damage we might do."

As climate change becomes an increasing concern, geoengineering is making a comeback. Scientists are looking at the atmosphere, the ocean, the land and even space to create a variety of effects, including helping to reduce the effect of sunlight on the Earth and sequestering carbon.

Seeding the ocean

US firm Climos plans to seed the ocean with iron particles. This will encourage the development of phytoplankton, it says, which carry large amounts of carbon to the ocean floor when they die. The company hopes to turn a profit by selling carbon credits.

Others are hoping to achieve a similar effect by bringing things up from underneath the ocean, rather than dropping things in from the surface. Atmocean plans to put large tubes in the ocean which will move vertically with the waves, pumping cool water to the surface from 200 metres down, says chief executive Phil Kithil. This will bring more nutrients with it, encouraging the phytoplankton to grow, he hopes.

Kithil adds that there's another benefit: "You're also reducing hurricane intensity by cooling the upper ocean." He argues that deploying these pumps over a roughly 60 x 60km area at one every 500 metres would bring enough cool water to the surface to reduce the intensity of a hurricane or perhaps even divert it, but ultimately he thinks the tubes could cover 80% of the ocean's surface for CO2 sequestration purposes.

Peter Flynn has oceanographic ideas of his own. The professor of mechanical engineering at Canada's University of Alberta cites worries about the Gulf Stream, which cycles warm water from the south Atlantic to the north, and sends cooler water back again. Salty water in the north sinks to the ocean floor and keeps the cycle moving. Should melting fresh water from the Arctic north shut down the pump, the results could be catastrophic, and Europe could be plunged into an ice age. Flynn proposed re-icing the Arctic using 8,000 giant floating platforms that would draw salty water from the ocean and spray it on to winter ice, dramatically increasing its thickness. It would continue to do this in the summer, which would then melt the ice and send tonnes of salty water plunging into the Gulf Stream.

Looking to the stars

Roger Angel, director of the Centre for Astronomical Adaptive Optics at the University of Arizona, is looking to the stars rather than the sea. He wants to put a mesh of tiny light refractors into space to sit between the Earth and the sun. The material would bend some of the sun's rays away from the planet.

"It's probably the most expensive and the cleanest," says Angel, who would need 16 trillion gossamer-light spacecraft, each sitting about a kilometre apart. Roughly 5m tonnes of material would be shot into space by a large magnetic railgun seated at the top of a mountain near the equator. Other than the $1tn (£500bn) launch cost, the other downside would be the 30 years needed to get them up there.

One of the upsides of the project is that it is reversible. Control craft would be needed to keep the others in exact position (using energy harvested from the solar light that they would be diverting). The control craft could move the array of reflectors out of the earth's orbit. In theory, the solar rays that contribute to climate change could be dialed up and down. "But whose hand is on that knob?" asks Caldeira. Whoever controlled the technology would be in a position of significant power. Getting everyone in the world to agree on climactic issues was difficult enough in Kyoto. And things could get even stormier when climactic, technological, and political fronts collide.

"Let's say Europe and North America don't reduce their carbon emissions, and China has a decade-long drought," Caldeira says. "It could say, 'You guys wrecked our climate, and we're going to engineer our own climate to repair things'."

Complicated outcomes

One of the biggest worries for Robock is that such tinkering could produce complicated outcomes. For example, spraying sulphur into the atmosphere might reduce the sunlight by 2%, he argues, but what will it do to the rain? "You might reduce precipitation," he says. "Preliminary results from calculations suggest that the Asian monsoon would be affected, which provides food for billions in Asia."

Some would-be ecohackers such as Espy may have been over-optimistic, but most of today's geoengineers are more cautious in their studies. Flynn says that his system would only be useful if we reached a tipping point.

Angel proposes amortising the cost of his project over 50 years. "You could say that a minimum of 100 million people would have their way of life ruined," says Flynn, musing about a gulf-stream shutdown. The $50bn that he'd need to mitigate the problem seems like a drop in the ocean when you consider that the money currently spent on the wars in Afghanistan and Iraq would pay for it in just over three months.

But hopefully we're not in B-movie territory yet. "The simplest thing is to stop putting in the gases that cause the warming," says Robock. When it comes to preventing the conditions that might make governments take geoengineering projects seriously, we all have our hands on the climate dial.

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iPhone 2.0: Solar-Powered Mobility

How many solar watches would it take to power an iPhone?

Solar energy is far from a new idea, but Apple (nasdaq: AAPL - news - people ) may be taking the technology to new limits. Many questions have been raised about the possibility–or probability–of Apple using solar energy to power portable devices such as its popular iPhones. It recently became known that employees at the computer, phone and software company have filed a patent to place solar cells on portable devices. (See " Apple’s Solar Strategy")

It’s not a new technology. Rudimentary findings of the potential to harness the sun’s powerful rays for conversion into electricity were first reported in the mid-1800s. The “photovoltaic effect” was discovered by then 19-year-old French physicist Edmund Becquerel in 1839.

Pocket calculators and wristwatches that operate on solar energy have been on the market for many years and are widely used. In 1957, two Pennsylvania engineers marketed a solar powered radio that was smaller than today’s iPod. The technology has come a long way since then and Apple may be the next to capitalize on it.

The biggest difference between those technologies and the patent for which Apple filed is the amount of power consumed by the product, said Michael Filler, a Caltech postdoctoral scholar specializing in photovoltaics.

iPhones are remarkably advanced devices that are small but consume considerable amounts of power. According to Filler’s calculations, it would take 250,000 to 1 million solar-powered wrist watches to generate the energy needed to power one iPhone (and keep the watches ticking). In other words, “the rate of energy consumption of the iPhone is about 250,000 to 1 million times larger than a standard sports wrist watch.” Filler’s calculation is for power consumption rates when both are being used, and take into account that the watch is used 24/7 while the iPhone is used for periods of time and then stored.

Concerns exist over the application of solar energy in portable devices such as cell phones, which are typically stored in pockets or purses and therefore are not constantly exposed to light. Also, while silicon solar cells do not need direct sunlight to work, they will collect a lot less energy indoors or on a cloudy day. Still, Filler said that a solar-powered iPhone “seems reasonable enough.”

The most efficient solar cells on the market convert the sun’s energy into electricity at about 20% efficiency, Filler said. In an optimal use environment, say on a cloudless sunny day in the desert outside Las Vegas, an iPhone equipped with Apple’s potential new technology could generate around 1 watt of energy, Filler explained. “It’s not going to be able to power the entire device but could extend battery life.” Almost anything solar-powered would still need to have a battery to store the captured energy.

Filler also pointed out that there are solar cells that operate at closer to 40% efficiency rates, but they are so expensive that they are mainly used by NASA for spacecraft, satellites and other space-related applications.

According to Apple’s pending patent, devices would integrate the solar cells underneath the liquid crystal display, or LCD, screens. Sandwiching the solar cells inside the device would block some light out and knock down power conversion efficiency even further, Filler cautioned. The light-emitting diode, or LED, of devices like the iPhone are designed to reflect light outwards toward the user. Theoretically, Filler said, if some fraction of the LED were projected backwards into the system, embedded solar cells could capture some of that light as well.

Perhaps the most obvious obstacle Apple may face will be the potential limitation for a gadget meant to be so small to have a large enough surface area on which to embed the solar cells. “Apple has done such a superb job packing so much function into such a small package, that not much area is available to harvest sunlight, even if you were standing in the middle of the desert somewhere in Nevada,” Filler said.

Scott Bourne, executive producer of the Apple iPhone Show on iTunes said he would not expect to see the implementation of a product of this kind for at least five years, but said that it is exciting to consider that it could happen. “Cell phone battery power is always an issue for users who inevitably want longer-lasting power than they have,” he said.

An Apple spokesperson would not comment on anything beyond what was written in the patent.

Apple devotees will just have to wait and wonder. Or buy the company's anti-gravitational stock: Shares of Apple traded up $5.18, or 2.9%, to close at $186.35 in trading Tuesday.

Filler added that those in the photovoltaic field hope to see solar conversional devices in everything we own, including roof shingles, sign posts, clothing, etc. “We want to see solar go beyond major power generation. The iPhone is one example.”

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Wisconsin governor signs Great Lakes compact

(AP) -- Gov. Jim Doyle has signed legislation making Wisconsin the fifth state to approve an interstate compact aimed at protecting the Great Lakes.

"This historic accord means that we will be managing our Great Lakes water in a sustainable way that will protect one of the world's greatest natural resources," Doyle said during a windy ceremony Tuesday on the Lake Michigan shoreline.

The compact would ban most diversions of water from the lakes' basin. Cities that straddle the basin's border or lie within counties that straddle the border could apply for an exemption. But any Great Lakes governor could block an exemption as well as withdrawals from outside the basin.

The eight Great Lakes governors signed the compact in 2005 after four years of negotiations, but it must be approved by each of the states and ratified by Congress before it can become law.

Wisconsin, Illinois, Indiana, Minnesota and New York, have now approved the measure, as have the Canadian provinces of Quebec and Ontario. Michigan, Ohio and Pennsylvania have yet to do so.

The pact was motivated largely by fears that states such as Arizona and Nevada in the booming but arid Southwest will try tapping into the lakes, which hold 90 percent of the nation's fresh surface water.

"People are already looking enviously at this water," Doyle said. "The Great Lakes define this region, and their waters sustain our recreation, our way of life, and our economy."

The lakes generate $55 billion a year in tourism for the region and provide more than 11,000 jobs in Wisconsin's ports, Doyle said.

© 2008 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.

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